Science.gov

Sample records for aircraft structural test

  1. Structural testing of concorde aircraft: Further report on United Kingdom tests

    NASA Technical Reports Server (NTRS)

    Harpur, N.

    1972-01-01

    A summary of tests conducted on the Concorde aircraft nacelle structure is presented. The tests were conducted as a part of the structural development and certification program. The nacelle structural specimens are described. The problems associated with the intake testing and engine-bay and nozzle testing are discussed.

  2. X-29A aircraft structural loads flight testing

    NASA Technical Reports Server (NTRS)

    Sims, Robert; Mccrosson, Paul; Ryan, Robert; Rivera, Joe

    1989-01-01

    The X-29A research and technology demonstrator aircraft has completed a highly successful multiphase flight test program. The primary research objective was to safely explore, evaluate, and validate a number of aerodynamic, structural, and flight control technologies, all highly integrated into the vehicle design. Most of these advanced technologies, particularly the forward-swept-wing platform, had a major impact on the structural design. Throughout the flight test program, structural loads clearance was an ongoing activity to provide a safe maneuvering envelope sufficient to accomplish the research objectives. An overview is presented of the technologies, flight test approach, key results, and lessons learned from the structural flight loads perspective. The overall design methodology was considered validated, but a number of structural load characteristics were either not adequately predicted or totally unanticipated prior to flight test. While conventional flight testing techniques were adequate to insure flight safety, advanced analysis tools played a key role in understanding some of the structural load characteristics, and in maximizing flight test productivity.

  3. Development of a biaxial test facility for structural evaluation of aircraft fuselage panels

    SciTech Connect

    Roach, D.; Walkington, P.; Rice, T.

    1998-03-01

    The number of commercial airframes exceeding twenty years of service continues to grow. An unavoidable by-product of aircraft use is that crack and corrosion flaws develop throughout the aircraft`s skin and substructure elements. Economic barriers to the purchase of new aircraft have created an aging aircraft fleet and placed even greater demands on efficient and safe repair methods. Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The composite doubler repair process produces both engineering and economic benefits. The FAA`s Airworthiness Assurance Center at Sandia National Labs completed a project to introduce composite doubler repair technology to the commercial aircraft industry. This paper focuses on a specialized structural test facility which was developed to evaluate the performance of composite doublers on actual aircraft structure. The facility can subject an aircraft fuselage section to a combined load environment of pressure (hoop stress) and axial, or longitudinal, stress. The tests simulate maximum cabin pressure loads and use a computerized feedback system to maintain the proper ratio between hoop and axial loads. Through the use of this full-scale test facility it was possible to: (1) assess general composite doubler response in representative flight load scenarios, and (2) verify the design and analysis approaches as applied to an L-1011 door corner repair.

  4. Creating a Test Validated Structural Dynamic Finite Element Model of the X-56A Aircraft

    NASA Technical Reports Server (NTRS)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the Multi Utility Technology Test-bed, X-56A aircraft, is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground vibration test-validated structural dynamic finite element model of the X-56A aircraft is created in this study. The structural dynamic finite element model of the X-56A aircraft is improved using a model tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, while other properties such as center of gravity location, total weight, and offdiagonal terms of the mass orthogonality matrix were used as constraints. The end result was a more improved and desirable structural dynamic finite element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  5. Creating a Test-Validated Finite-Element Model of the X-56A Aircraft Structure

    NASA Technical Reports Server (NTRS)

    Pak, Chan-Gi; Truong, Samson

    2014-01-01

    Small modeling errors in a finite-element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the X-56A Multi-Utility Technology Testbed aircraft is the flight demonstration of active flutter suppression and, therefore, in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground-vibration test-validated structural dynamic finite-element model of the X-56A aircraft is created in this study. The structural dynamic finite-element model of the X-56A aircraft is improved using a model-tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, whereas other properties such as c.g. location, total weight, and off-diagonal terms of the mass orthogonality matrix were used as constraints. The end result was an improved structural dynamic finite-element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  6. Structural dynamics research in a full-scale transport aircraft crash test

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr.; Hayduk, R. J.; Thomson, R. G.

    1986-01-01

    A remotely piloted air-to-ground crash test of a full-scale transport aircraft was conducted for the first time for two purposes: (1) to demonstrate performance of an antimisting fuel additive in suppressing fire in a crash environment, and (2) to obtain structural dynamics data under crash conditions for comparison with analytical predictions. The test, called the Controlled Impact Demonstration (CID), was sponsored by FAA and NASA with cooperation of industry, the Department of Defense, and the British and French governments. The test aircraft was a Boeing 720 jet transport. The aircraft impacted a dry lakebed at Edwards Air Force Base, CA. The purpose of this paper is to discuss the structural aspects of the CID. The fuselage section tests and the CID itself are described. Structural response data from these tests are presented and discussed. Nonlinear analytical modeling efforts are described, and comparisons between analytical results and experimental results are presented.

  7. Loading tests of a wing structure for a hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Fields, R. A.; Reardon, L. F.; Siegel, W. H.

    1980-01-01

    Room-temperature loading tests were conducted on a wing structure designed with a beaded panel concept for a Mach 8 hypersonic research airplane. Strain, stress, and deflection data were compared with the results of three finite-element structural analysis computer programs and with design data. The test program data were used to evaluate the structural concept and the methods of analysis used in the design. A force stiffness technique was utilized in conjunction with load conditions which produced various combinations of panel shear and compression loading to determine the failure envelope of the buckling critical beaded panels The force-stiffness data did not result in any predictions of buckling failure. It was, therefore, concluded that the panels were conservatively designed as a result of design constraints and assumptions of panel eccentricities. The analysis programs calculated strains and stresses competently. Comparisons between calculated and measured structural deflections showed good agreement. The test program offered a positive demonstration of the beaded panel concept subjected to room-temperature load conditions.

  8. Full-Scale Structural and NDI Validation Tests of Bonded Composite Doublers for Commercial Aircraft Applications

    SciTech Connect

    Roach, D.; Walkington, P.

    1999-02-01

    Composite doublers, or repair patches, provide an innovative repair technique which can enhance the way aircraft are maintained. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is possible to bond a single Boron-Epoxy composite doubler to the damaged structure. Most of the concerns surrounding composite doubler technology pertain to long-term survivability, especially in the presence of non-optimum installations, and the validation of appropriate inspection procedures. This report focuses on a series of full-scale structural and nondestructive inspection (NDI) tests that were conducted to investigate the performance of Boron-Epoxy composite doublers. Full-scale tests were conducted on fuselage panels cut from retired aircraft. These full-scale tests studied stress reductions, crack mitigation, and load transfer capabilities of composite doublers using simulated flight conditions of cabin pressure and axial stress. Also, structures which modeled key aspects of aircraft structure repairs were subjected to extreme tension, shear and bending loads to examine the composite laminate's resistance to disbond and delamination flaws. Several of the structures were loaded to failure in order to determine doubler design margins. Nondestructive inspections were conducted throughout the test series in order to validate appropriate techniques on actual aircraft structure. The test results showed that a properly designed and installed composite doubler is able to enhance fatigue life, transfer load away from damaged structure, and avoid the introduction of new stress risers (i.e. eliminate global reduction in the fatigue life of the structure). Comparisons with test data obtained prior to the doubler installation revealed that stresses in the parent material can be reduced 30%--60% through the use of the composite doubler. Tests to failure demonstrated that the bondline is able to transfer plastic strains into the doubler and that the

  9. Report on the test set-up for the structural testing of the Airmass Sunburst Ultralight Aircraft

    NASA Technical Reports Server (NTRS)

    Zimmerman, William; Smith, Howard W.

    1993-01-01

    This report reviews the test set-up and procedure for the structural testing of the Airmass Sunburst Ultralight Aircraft. In general aviation today, there is a growing need for more stringent design criteria for ultralight aircraft. Unlike most general aviation aircraft, the ultralight lacks sufficient design criteria and more importantly it lacks sufficient certification enforcement. The Airmass Sunburst ultralight that is currently being tested is responsible for over a dozen deaths. It is believed that had there been a more stringent criteria and certification process, this might have been prevented. Our attempt is to show that the failing loads of the aircraft in question are so far below that of the current design criteria, that the laws need to be changed.

  10. Analyses and tests of the B-1 aircraft structural mode control system

    NASA Technical Reports Server (NTRS)

    Wykes, J. H.; Byar, T. R.; Macmiller, C. J.; Greek, D. C.

    1980-01-01

    Analyses and flight tests of the B-1 structural mode control system (SMCS) are presented. Improvements in the total dynamic response of a flexible aircraft and the benefits to ride qualities, handling qualities, crew efficiency, and reduced dynamic loads on the primary structures, were investigated. The effectiveness and the performance of the SMCS, which uses small aerodynamic surfaces at the vehicle nose to provide damping to the structural modes, were evaluated.

  11. The Ultra Light Aircraft Testing

    NASA Technical Reports Server (NTRS)

    Smith, Howard W.

    1993-01-01

    The final report for grant NAG1-345 is presented. Recently, the bulk of the work that the grant has supported has been in the areas of ride quality and the structural analysis and testing of ultralight aircraft. The ride quality work ended in May 1989. Hence, the papers presented in this final report are concerned with ultralight aircraft.

  12. Dynamic structural aeroelastic stability testing of the XV-15 tilt rotor research aircraft

    NASA Technical Reports Server (NTRS)

    Schroers, L. G.

    1982-01-01

    For the past 20 years, a significant effort has been made to understand and predict the structural aeroelastic stability characteristics of the tilt rotor concept. Beginning with the rotor-pylon oscillation of the XV-3 aircraft, the problem was identified and then subjected to a series of theoretical studies, plus model and full-scale wind tunnel tests. From this data base, methods were developed to predict the structural aeroelastic stability characteristics of the XV-15 Tilt Rotor Research Aircraft. The predicted aeroelastic characteristics are examined in light of the major parameters effecting rotor-pylon-wing stability. Flight test techniques used to obtain XV-15 aeroelastic stability are described. Flight test results are summarized and compared to the predicted values. Wind tunnel results are compared to flight test results and correlated with predicted values.

  13. Critical joints in large composite primary aircraft structures. Volume 2: Technology demonstration test report

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints in composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of four large composite multirow bolted joint tests are presented. The tests were conducted to demonstrate the technology for critical joints in highly loaded composite structure and to verify the analytical methods that were developed throughout the program. The test consisted of a wing skin-stringer transition specimen representing a stringer runout and skin splice on the wing lower surface at the side of the fuselage attachment. All tests were static tension tests. The composite material was Toray T-300 fiber with Ciba-Geigy 914 resin in 10 mil tape form. The splice members were metallic, using combinations of aluminum and titanium. Discussions are given of the test article, instrumentation, test setup, test procedures, and test results for each of the four specimens. Some of the analytical predictions are also included.

  14. Critical Joints in Large Composite Primary Aircraft Structures. Volume 3: Ancillary Test Results

    NASA Technical Reports Server (NTRS)

    Bunin, Bruce L.; Sagui, R. L.

    1985-01-01

    A program was conducted to develop the technology for critical structural joints for composite wing structure that meets all the design requirements of a 1990 commercial transport aircraft. The results of a comprehensive ancillary test program are summarized, consisting of single-bolt composite joint specimens tested in a variety of configurations. These tests were conducted to characterize the strength and load deflection properties that are required for multirow joint analysis. The composite material was Toray 300 fiber and Ciba-Geigy 914 resin, in the form of 0.005 and 0.01 inch thick unidirectional tape. Tests were conducted in single and double shear for loaded and unloaded hole configurations under both tensile and compressive loading. Two different layup patterns were examined. All tests were conducted at room temperature. In addition, the results of NASA Standard Toughness Test (NASA RP 1092) are reported, which were conducted for several material systems.

  15. OVRhyp, Scramjet Test Aircraft

    NASA Technical Reports Server (NTRS)

    Aslan, J.; Bisard, T.; Dallinga, S.; Draper, K.; Hufford, G.; Peters, W.; Rogers, J.

    1990-01-01

    A preliminary design for an unmanned hypersonic research vehicle to test scramjet engines is presented. The aircraft will be launched from a carrier aircraft at an altitude of 40,000 feet at Mach 0.8. The vehicle will then accelerate to Mach 6 at an altitude of 100,000 feet. At this stage the prototype scramjet will be employed to accelerate the vehicle to Mach 10 and maintain Mach 10 flight for 2 minutes. The aircraft will then decelerate and safely land.

  16. Designing for aircraft structural crashworthiness

    NASA Technical Reports Server (NTRS)

    Thomson, R. G.; Caiafa, C.

    1981-01-01

    This report describes structural aviation crash dynamics research activities being conducted on general aviation aircraft and transport aircraft. The report includes experimental and analytical correlations of load-limiting subfloor and seat configurations tested dynamically in vertical drop tests and in a horizontal sled deceleration facility. Computer predictions using a finite-element nonlinear computer program, DYCAST, of the acceleration time-histories of these innovative seat and subfloor structures are presented. Proposed application of these computer techniques, and the nonlinear lumped mass computer program KRASH, to transport aircraft crash dynamics is discussed. A proposed FAA full-scale crash test of a fully instrumented radio controlled transport airplane is also described.

  17. Analysis and Testing of a Metallic Repair Applicable to Pressurized Composite Aircraft Structure

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Rouse, Marshall; Lovejoy, Andrew E.

    2014-01-01

    Development of repair technology is vital to the long-term application of new structural concepts on aircraft structure. The design, analysis, and testing of a repair concept applicable to a stiffened composite panel based on the Pultruded Rod Stitched Efficient Unitized Structure was recently completed. The damage scenario considered was a mid-bay to mid-bay saw-cut with a severed stiffener, flange, and skin. A bolted metallic repair was selected so that it could be easily applied in the operational environment. The present work describes results obtained from tension and pressure panel tests conducted to validate both the repair concept and finite element analysis techniques used in the design effort. Simulation and experimental strain and displacement results show good correlation, indicating that the finite element modeling techniques applied in the effort are an appropriate compromise between required fidelity and computational effort. Static tests under tension and pressure loadings proved that the proposed repair concept is capable of sustaining load levels that are higher than those resulting from the current working stress allowables. Furthermore, the pressure repair panel was subjected to 55,000 pressure load cycles to verify that the design can withstand a life cycle representative for a transport category aircraft. These findings enable upward revision of the stress allowables that had been kept at an overly-conservative level due to concerns associated with repairability of the panels. This conclusion enables more weight efficient structural designs utilizing the composite concept under investigation.

  18. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure . Part II; Severe Damage

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a finite element analysis and the testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part II of the paper considers the final test to failure of the test article in the presence of an intentionally inflicted severe discrete source damage under the wing up-bending loading condition. Finite element analysis results are compared with measurements acquired during the test and demonstrate that the hybrid wing body test article was able to redistribute and support the required design loads in a severely damaged condition.

  19. The Philosophy which underlies the structural tests of a supersonic transport aircraft with particular attention to the thermal cycle

    NASA Technical Reports Server (NTRS)

    Ripley, E. L.

    1972-01-01

    The information presented is based on data obtained from the Concorde. Much of this data also applies to other supersonic transport aircraft. The design and development of the Concorde is a joint effort of the British and French, and the structural test program is shared, as are all the other activities. Vast numbers of small specimens have been tested to determine the behavior of the materials used in the aircraft. Major components of the aircraft structure, totalling almost a complete aircraft, have been made and are being tested to help the constructors in each country in the design and development of the structure. Tests on two complete airframes will give information for the certification of the aircraft. A static test was conducted in France and a fatigue test in the United Kingdom. Fail-safe tests are being made to demonstrate the crack-propagation characteristics of the structure and its residual strength. Aspects of the structural test program are described in some detail, dealing particularly with the problems associated with the thermal cycle. The biggest of these problems is the setting up of the fatigue test on the complete airframe; therefore, this is covered more extensively with a discussion about how the test time can be shortened and with a description of the practical aspects of the test.

  20. Fuel containment and damage tolerance in large composite primary aircraft structures. Phase 2: Testing

    NASA Technical Reports Server (NTRS)

    Sandifer, J. P.; Denny, A.; Wood, M. A.

    1985-01-01

    Technical issues associated with fuel containment and damage tolerance of composite wing structures for transport aircraft were investigated. Material evaluation tests were conducted on two toughened resin composites: Celion/HX1504 and Celion/5245. These consisted of impact, tension, compression, edge delamination, and double cantilever beam tests. Another test series was conducted on graphite/epoxy box beams simulating a wing cover to spar cap joint configuration of a pressurized fuel tank. These tests evaluated the effectiveness of sealing methods with various fastener types and spacings under fatigue loading and with pressurized fuel. Another test series evaluated the ability of the selected coatings, film, and materials to prevent fuel leakage through 32-ply AS4/2220-1 laminates at various impact energy levels. To verify the structural integrity of the technology demonstration article structural details, tests were conducted on blade stiffened panels and sections. Compression tests were performed on undamaged and impacted stiffened AS4/2220-1 panels and smaller element tests to evaluate stiffener pull-off, side load and failsafe properties. Compression tests were also performed on panels subjected to Zone 2 lightning strikes. All of these data were integrated into a demonstration article representing a moderately loaded area of a transport wing. This test combined lightning strike, pressurized fuel, impact, impact repair, fatigue and residual strength.

  1. Structural integrity in aircraft.

    NASA Technical Reports Server (NTRS)

    Hardrath, H. F.

    1973-01-01

    The paper reviews briefly the current design philosophies for achieving long, efficient, and reliable service in aircraft structures. The strengths and weaknesses of these design philosophies and their demonstrated records of success are discussed. The state of the art has not been developed to the point where designing can be done without major test inspection and maintenance programs. A broad program of research is proposed through which a viable computerized design scheme will be provided during the next decade. The program will organize and correlate existing knowledge on fatigue and fracture behavior, identify gaps in this knowledge, and guide specific research to upgrade design capabilities.

  2. Composite structural materials. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1980-01-01

    The use of filamentary composite materials in the design and construction of primary aircraft structures is considered with emphasis on efforts to develop advanced technology in the areas of physical properties, structural concepts and analysis, manufacturing, and reliability and life prediction. The redesign of a main spar/rib region on the Boeing 727 elevator near its actuator attachment point is discussed. A composite fabrication and test facility is described as well as the use of minicomputers for computer aided design. Other topics covered include (1) advanced structural analysis methids for composites; (2) ultrasonic nondestructive testing of composite structures; (3) optimum combination of hardeners in the cure of epoxy; (4) fatigue in composite materials; (5) resin matrix characterization and properties; (6) postbuckling analysis of curved laminate composite panels; and (7) acoustic emission testing of composite tensile specimens.

  3. Aircraft Flutter Testing

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Wilmer Reed gained international recognition for his innovative research, contributions and patented ideas relating to flutter and aeroelasticity of aerospace vehicles at Langley Research Center. In the early 1980's, Reed retired from Langley and joined the engineering staff of Dynamic Engineering Inc. While at DEI, Reed conceived and patented the DEI Flutter Exciter, now used world-wide in flight flutter testing of new or modified aircraft designs. When activated, the DEI Flutter Exciter alternately deflects the airstream upward and downward in a rapid manner, creating a force similar to that produced by an oscillating trailing edge flap. The DEI Flutter Exciter is readily adaptable to a variety of aircraft.

  4. Creating a Test Validated Structural Dynamic Finite Element Model of the Multi-Utility Technology Test Bed Aircraft

    NASA Technical Reports Server (NTRS)

    Pak, Chan-Gi; Truong, Samson S.

    2014-01-01

    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of Multi Utility Technology Test Bed, X-56A, aircraft is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of X-56A. The ground vibration test validated structural dynamic finite element model of the X-56A is created in this study. The structural dynamic finite element model of the X-56A is improved using a model tuning tool. In this study, two different weight configurations of the X-56A have been improved in a single optimization run.

  5. Lightning protection guidelines and test data for adhesively bonded aircraft structures

    NASA Technical Reports Server (NTRS)

    Pryzby, J. E.; Plumer, J. A.

    1984-01-01

    The highly competitive marketplace and increasing cost of energy has motivated manufacturers of general aviation aircraft to utilize composite materials and metal-to-metal bonding in place of conventional fasteners and rivets to reduce weight, obtain smoother outside surfaces and reduce drag. The purpose of this program is protection of these new structures from hazardous lightning effects. The program began with a survey of advance-technology materials and fabrication methods under consideration for future designs. Sub-element specimens were subjected to simulated lightning voltages and currents. Measurements of bond line voltages, electrical sparking, and mechanical strength degradation were made to comprise a data base of electrical properties for new technology materials and basic structural configurations. The second hase of the program involved tests on full scale wing structures which contained integral fuel tanks and which were representative of examples of new technology structures and fuel systems. The purpose of these tests was to provide a comparison between full scale structural measurements and those obtained from the sub-element specimens.

  6. Composite structural materials. [aircraft applications

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberley, S. E.

    1981-01-01

    The development of composite materials for aircraft applications is addressed with specific consideration of physical properties, structural concepts and analysis, manufacturing, reliability, and life prediction. The design and flight testing of composite ultralight gliders is documented. Advances in computer aided design and methods for nondestructive testing are also discussed.

  7. Fuel containment and damage tolerance for large composite primary aircraft structures. Phase 1: Testing

    NASA Technical Reports Server (NTRS)

    Sandifer, J. P.

    1983-01-01

    Technical problems associated with fuel containment and damage tolerance of composite material wings for transport aircraft were identified. The major tasks are the following: (1) the preliminary design of damage tolerant wing surface using composite materials; (2) the evaluation of fuel sealing and lightning protection methods for a composite material wing; and (3) an experimental investigation of the damage tolerant characteristics of toughened resin graphite/epoxy materials. The test results, the test techniques, and the test data are presented.

  8. NDE: An effective approach to improved reliability and safety. A technology survey. [nondestructive testing of aircraft structures

    NASA Technical Reports Server (NTRS)

    Carpenter, J. L., Jr.; Stuhrke, W. F.

    1976-01-01

    Technical abstracts are presented for about 100 significant documents relating to nondestructive testing of aircraft structures or related structural testing and the reliability of the more commonly used evaluation methods. Particular attention is directed toward acoustic emission; liquid penetrant; magnetic particle; ultrasonics; eddy current; and radiography. The introduction of the report includes an overview of the state-of-the-art represented in the documents that have been abstracted.

  9. Full-scale testing and progressive damage modeling of sandwich composite aircraft fuselage structure

    NASA Astrophysics Data System (ADS)

    Leone, Frank A., Jr.

    A comprehensive experimental and computational investigation was conducted to characterize the fracture behavior and structural response of large sandwich composite aircraft fuselage panels containing artificial damage in the form of holes and notches. Full-scale tests were conducted where panels were subjected to quasi-static combined pressure, hoop, and axial loading up to failure. The panels were constructed using plain-weave carbon/epoxy prepreg face sheets and a Nomex honeycomb core. Panel deformation and notch tip damage development were monitored during the tests using several techniques, including optical observations, strain gages, digital image correlation (DIC), acoustic emission (AE), and frequency response (FR). Additional pretest and posttest inspections were performed via thermography, computer-aided tap tests, ultrasound, x-radiography, and scanning electron microscopy. The framework to simulate damage progression and to predict residual strength through use of the finite element (FE) method was developed. The DIC provided local and full-field strain fields corresponding to changes in the state-of-damage and identified the strain components driving damage progression. AE was monitored during loading of all panels and data analysis methodologies were developed to enable real-time determination of damage initiation, progression, and severity in large composite structures. The FR technique has been developed, evaluating its potential as a real-time nondestructive inspection technique applicable to large composite structures. Due to the large disparity in scale between the fuselage panels and the artificial damage, a global/local analysis was performed. The global FE models fully represented the specific geometries, composite lay-ups, and loading mechanisms of the full-scale tests. A progressive damage model was implemented in the local FE models, allowing the gradual failure of elements in the vicinity of the artificial damage. A set of modifications

  10. Testing a theory of aircraft noise annoyance: a structural equation analysis.

    PubMed

    Kroesen, Maarten; Molin, Eric J E; van Wee, Bert

    2008-06-01

    Previous research has stressed the relevance of nonacoustical factors in the perception of aircraft noise. However, it is largely empirically driven and lacks a sound theoretical basis. In this paper, a theoretical model which explains noise annoyance based on the psychological stress theory is empirically tested. The model is estimated by applying structural equation modeling based on data from residents living in the vicinity of Amsterdam Airport Schiphol in The Netherlands. The model provides a good model fit and indicates that concern about the negative health effects of noise and pollution, perceived disturbance, and perceived control and coping capacity are the most important variables that explain noise annoyance. Furthermore, the model provides evidence for the existence of two reciprocal relationships between (1) perceived disturbance and noise annoyance and (2) perceived control and coping capacity and noise annoyance. Lastly, the model yielded two unexpected results. Firstly, the variables noise sensitivity and fear related to the noise source were unable to explain additional variance in the endogenous variables of the model and were therefore excluded from the model. And secondly, the size of the total effect of noise exposure on noise annoyance was relatively small. The paper concludes with some recommended directions for further research. PMID:18537376

  11. Safe structures for future aircraft

    NASA Technical Reports Server (NTRS)

    Mccomb, H. G., Jr.

    1983-01-01

    The failure mechanisms, design lessons, and test equipment employed by NASA in establishing the airworthiness and crashworthiness of aircraft components for commercial applications are described. The composites test programs have progressed to medium primary structures such as stabilizers and a vertical fin. The failures encountered to date have been due to the nonyielding nature of composites, which do not diffuse loads like metals, and the presence of eccentricities, irregular shapes, stiffness changes, and discontinuities that cause tension and shear. Testing to failure, which always occurred in first tests before the design loads were reached, helped identify design changes and reinforcements that produced successful products. New materials and NDE techniques are identified, together with aircraft structural design changes that offer greater protection to the passengers, fuel antimisting agents, and landing gear systems.

  12. Dynamic response of aircraft structure

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The physical and mathematical problems associated with the response of elastic structures to random excitations such as occurs during buffeting and other transonic phenomena were discussed. The following subjects were covered: (1) general dynamic system consisting of the aircraft structure, the aerodynamic driving forces due to separated flow, and the aerodynamic forces due to aircraft structural motion, (2) structural and aerodynamic quantities of the dynamic system with special emphasis given to the description of the aerodynamic forces, and including a treatment of similarity laws, scaling effects, and wind tunnel testing, and (3) methods for data processing of fluctuating pressure recordings and techniques for response analysis for random excitation. A general buffeting flutter model, which takes into account the interactions between the separated and motion induced flows was presented. Relaxations of this model leading to the forced vibration model were explained.

  13. The Cleveland Aircraft Fire Tests

    NASA Technical Reports Server (NTRS)

    Brenneman, James J.; Heine, Donald A.

    1968-01-01

    On June 30 and July 1, 1966, tests were conducted to evaluate high expansion foam's ability to extend the time for which an aircraft passenger cabin environment would remain survivable during a post-crash fire. While some results tend to confirm those of similar tests, others may shed new light on the problem.

  14. Testing and Analysis of a Composite Non-Cylindrical Aircraft Fuselage Structure. Part 1; Ultimate Design Loads

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Jegley, Dawn C.; Lovejoy, Andrew E.; Rouse, Marshall; Wu, Hsi-Yung T.

    2016-01-01

    The Environmentally Responsible Aviation Project aimed to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration were not sufficient to achieve the desired metrics. One airframe concept identified by the project as having the potential to dramatically improve aircraft performance was a composite-based hybrid wing body configuration. Such a concept, however, presented inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses finite element analysis and testing of a large-scale hybrid wing body center section structure developed and constructed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. Part I of the paper considers the five most critical load conditions, which are internal pressure only and positive and negative g-loads with and without internal pressure. Analysis results are compared with measurements acquired during testing. Performance of the test article is found to be closely aligned with predictions and, consequently, able to support the hybrid wing body design loads in pristine and barely visible impact damage conditions.

  15. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two design techniques for linear flight test trajectory controllers (FTTCs) are described: Eigenstructure assignment and the minimum error excitation technique. The two techniques are used to design FTTCs for an F-15 aircraft model for eight different maneuvers at thirty different flight conditions. An evaluation of the FTTCs is presented.

  16. Aircraft structures research at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Duberg, John E

    1955-01-01

    A review is made of the test techniques that have been developed and used by the NACA for experimental research in aircraft structures at elevated temperatures. Some experimental results are presented. Remarks are included on the problem of model scaling for testing of structures at high temperatures. (author)

  17. Ground vibration test results for Drones for Aerodynamic and Structural Testing (DAST)/Aeroelastic Research Wing (ARW-1R) aircraft

    NASA Technical Reports Server (NTRS)

    Cox, T. H.; Gilyard, G. B.

    1986-01-01

    The drones for aerodynamic and structural testing (DAST) project was designed to control flutter actively at high subsonic speeds. Accurate knowledge of the structural model was critical for the successful design of the control system. A ground vibration test was conducted on the DAST vehicle to determine the structural model characteristics. This report presents and discusses the vibration and test equipment, the test setup and procedures, and the antisymmetric and symmetric mode shape results. The modal characteristics were subsequently used to update the structural model employed in the control law design process.

  18. Commercial transport aircraft composite structures

    NASA Technical Reports Server (NTRS)

    Mccarty, J. E.

    1983-01-01

    The role that analysis plays in the development, production, and substantiation of aircraft structures is discussed. The types, elements, and applications of failure that are used and needed; the current application of analysis methods to commercial aircraft advanced composite structures, along with a projection of future needs; and some personal thoughts on analysis development goals and the elements of an approach to analysis development are discussed.

  19. Advanced technology composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Ilcewicz, Larry B.; Walker, Thomas H.

    1991-01-01

    Work performed during the 25th month on NAS1-18889, Advanced Technology Composite Aircraft Structures, is summarized. The main objective of this program is to develop an integrated technology and demonstrate a confidence level that permits the cost- and weight-effective use of advanced composite materials in primary structures of future aircraft with the emphasis on pressurized fuselages. The period from 1-31 May 1991 is covered.

  20. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

  1. 14 CFR 21.127 - Tests: aircraft.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Tests: aircraft. 21.127 Section 21.127... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.127 Tests: aircraft. (a) Each person manufacturing aircraft under a type certificate must establish an approved production flight test procedure...

  2. 14 CFR 21.127 - Tests: aircraft.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Tests: aircraft. 21.127 Section 21.127... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.127 Tests: aircraft. (a) Each person manufacturing aircraft under a type certificate must establish an approved production flight test procedure...

  3. Full-scale flight tests of aircraft morphing structures using SMA actuators

    NASA Astrophysics Data System (ADS)

    Mabe, James H.; Calkins, Frederick T.; Ruggeri, Robert T.

    2007-04-01

    In August of 2005 The Boeing Company conducted a full-scale flight test utilizing Shape Memory Alloy (SMA) actuators to morph an engine's fan exhaust to correlate exhaust geometry with jet noise reduction. The test was conducted on a 777-300ER with GE-115B engines. The presence of chevrons, serrated aerodynamic surfaces mounted at the trailing edge of the thrust reverser, have been shown to greatly reduce jet noise by encouraging advantageous mixing of the free, and fan streams. The morphing, or Variable Geometry Chevrons (VGC), utilized compact, light weight, and robust SMA actuators to morph the chevron shape to optimize the noise reduction or meet acoustic test objectives. The VGC system was designed for two modes of operation. The entirely autonomous operation utilized changes in the ambient temperature from take-off to cruise to activate the chevron shape change. It required no internal heaters, wiring, control system, or sensing. By design this provided one tip immersion at the warmer take-off temperatures to reduce community noise and another during the cooler cruise state for more efficient engine operation, i.e. reduced specific fuel consumption. For the flight tests a powered mode was added where internal heaters were used to individually control the VGC temperatures. This enabled us to vary the immersions and test a variety of chevron configurations. The flight test demonstrated the value of SMA actuators to solve a real world aerospace problem, validated that the technology could be safely integrated into the airplane's structure and flight system, and represented a large step forward in the realization of SMA actuators for production applications. In this paper the authors describe the development of the actuator system, the steps required to integrate the morphing structure into the thrust reverser, and the analysis and testing that was required to gain approval for flight. Issues related to material strength, thermal environment, vibration

  4. Aircraft propeller induced structure-borne noise

    NASA Technical Reports Server (NTRS)

    Unruh, James F.

    1989-01-01

    A laboratory-based test apparatus employing components typical of aircraft construction was developed that would allow the study of structure-borne noise transmission due to propeller induced wake/vortex excitation of in-wake structural appendages. The test apparatus was employed to evaluate several aircraft installation effects (power plant placement, engine/nacelle mass loading, and wing/fuselage attachment methods) and several structural response modifications for structure-borne noise control (the use of wing blocking mass/fuel, wing damping treaments, and tuned mechanical dampers). Most important was the development of in-flight structure-borne noise transmission detection techniques using a combination of ground-based frequency response function testing and in-flight structural response measurement. Propeller wake/vortex excitation simulation techniques for improved ground-based testing were also developed to support the in-flight structure-borne noise transmission detection development.

  5. 14 CFR 21.127 - Tests: aircraft.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Tests: aircraft. 21.127 Section 21.127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate § 21.127 Tests: aircraft. (a) Each...

  6. 14 CFR 21.127 - Tests: aircraft.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tests: aircraft. 21.127 Section 21.127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT CERTIFICATION PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate Only § 21.127 Tests: aircraft. (a)...

  7. Carbon fiber counting. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Pride, R. A.

    1980-01-01

    A method was developed for characterizing the number and lengths of carbon fibers accidentally released by the burning of composite portions of civil aircraft structure in a jet fuel fire after an accident. Representative samplings of carbon fibers collected on transparent sticky film were counted from photographic enlargements with a computer aided technique which also provided fiber lengths.

  8. 14 CFR 21.127 - Tests: aircraft.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tests: aircraft. 21.127 Section 21.127... PROCEDURES FOR PRODUCTS AND PARTS Production Under Type Certificate Only § 21.127 Tests: aircraft. (a) Each... test procedure and flight check-off form, and in accordance with that form, flight test each...

  9. High altitude aircraft flight tests

    NASA Astrophysics Data System (ADS)

    Helmken, Henry; Emmons, Peter; Homeyer, David

    1996-03-01

    In order to make low earth orbit L-band propagation measurements and test new voice communication concepts, a payload was proposed and accepted for flight aboard the COMET (now METEOR) spacecraft. This Low Earth Orbiting EXperiment payload (LEOEX) was designed and developed by Motorola Inc. and sponsored by the Space Communications Technology Center (SCTC), a NASA Center for the Commercial Development of Space (CCDS) located at Florida Atlantic University. In order to verify the LEOEX payload for satellite operation and obtain some preliminary propagation data, a series of 9 high altitude aircraft (SR-71 and ER-2) flight tests were conducted. These flights took place during a period of 7 months, from October 1993 to April 1994. This paper will summarize the operation of the LEOEX payload and the particular configuration used for these flights. The series of flyby tests were very successful and demonstrated how bi-directional, Time Division Multiple Access (TDMA) voice communication will work in space-to-ground L-band channels. The flight tests also acquired propagation data which will be representative of L-band Low Earth Orbiting (LEO) communication systems. In addition to verifying the LEOEX system operation, it also uncovered and ultimately aided the resolution of several key technical issues associated with the payload.

  10. Structural Health Monitoring of AN Aircraft Joint

    NASA Astrophysics Data System (ADS)

    Mickens, T.; Schulz, M.; Sundaresan, M.; Ghoshal, A.; Naser, A. S.; Reichmeider, R.

    2003-03-01

    A major concern with ageing aircraft is the deterioration of structural components in the form of fatigue cracks at fastener holes, loose rivets and debonding of joints. These faults in conjunction with corrosion can lead to multiple-site damage and pose a hazard to flight. Developing a simple vibration-based method of damage detection for monitoring ageing structures is considered in this paper. The method is intended to detect damage during operation of the vehicle before the damage can propagate and cause catastrophic failure of aircraft components. It is typical that only a limited number of sensors could be used on the structure and damage can occur anywhere on the surface or inside the structure. The research performed was to investigate use of the chirp vibration responses of an aircraft wing tip to detect, locate and approximately quantify damage. The technique uses four piezoelectric patches alternatively as actuators and sensors to send and receive vibration diagnostic signals.Loosening of selected screws simulated damage to the wing tip. The results obtained from the testing led to the concept of a sensor tape to detect damage at joints in an aircraft structure.

  11. Aircraft empennage structural detail design

    NASA Technical Reports Server (NTRS)

    Meholic, Greg; Brown, Rhonda; Hall, Melissa; Harvey, Robert; Singer, Michael; Tella, Gustavo

    1993-01-01

    This project involved the detailed design of the aft fuselage and empennage structure, vertical stabilizer, rudder, horizontal stabilizer, and elevator for the Triton primary flight trainer. The main design goals under consideration were to illustrate the integration of the control systems devices used in the tail surfaces and their necessary structural supports as well as the elevator trim, navigational lighting system, electrical systems, tail-located ground tie, and fuselage/cabin interface structure. Accommodations for maintenance, lubrication, adjustment, and repairability were devised. Weight, fabrication, and (sub)assembly goals were addressed. All designs were in accordance with the FAR Part 23 stipulations for a normal category aircraft.

  12. Structural design of supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Fischler, J. E.

    1976-01-01

    The major efforts leading to an efficient structural design include: (1) the analysis methods used to improve the structural model optimization and compare the structural concepts, (2) the analysis and description of the fail-safe, crack growth, and residual strength studies and tests, (3) baseline structural trade studies to determine optimum structural weights including effects of geometry changes, strength, fail-safety, aeroelastics and flutter, 6AL-4V annealed titanium in structural efficiency after 70,000 hours at temperature, (5) the study of three structural models for aircraft at 2.0 Mach, 2.2 Mach, and 2.4 Mach cruise speeds, (6) the study of many structural concepts to determine their weight efficiencies; and (7) the determination of the requirements for large-scale structural development testing.

  13. Aircraft wing structure detail design

    NASA Technical Reports Server (NTRS)

    Sager, Garrett L.; Roberts, Ron; Mallon, Bob; Alameri, Mohamed; Steinbach, Bill

    1993-01-01

    The provisions of this project call for the design of the structure of the wing and carry-through structure for the Viper primary trainer, which is to be certified as a utility category trainer under FAR part 23. The specific items to be designed in this statement of work were Front Spar, Rear Spar, Aileron Structure, Wing Skin, and Fuselage Carry-through Structure. In the design of these parts, provisions for the fuel system, electrical system, and control routing were required. Also, the total weight of the entire wing planform could not exceed 216 lbs. Since this aircraft is to be used as a primary trainer, and the SOW requires a useful life of 107 cycles, it was decided that all of the principle stresses in the structural members would be kept below 10 ksi. The only drawback to this approach is a weight penalty.

  14. Impact analysis of composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Pifko, Allan B.; Kushner, Alan S.

    1993-01-01

    The impact analysis of composite aircraft structures is discussed. Topics discussed include: background remarks on aircraft crashworthiness; comments on modeling strategies for crashworthiness simulation; initial study of simulation of progressive failure of an aircraft component constructed of composite material; and research direction in composite characterization for impact analysis.

  15. Structural analysis of light aircraft using NASTRAN

    NASA Technical Reports Server (NTRS)

    Wilkinson, M. T.; Bruce, A. C.

    1973-01-01

    An application of NASTRAN to the structural analysis of light aircraft was conducted to determine the cost effectiveness. A model of the Baby Ace D model homebuilt aircraft was used. The NASTRAN model of the aircraft consists of 193 grid points connected by 352 structural members. All members are either rod or beam elements, including bending of unsymmetrical cross sections and torsion of noncircular cross sections. The aerodynamic loads applied to the aircraft were in accordance with FAA regulations governing the utility category aircraft.

  16. Fatigue experience from tests carried out with forged beam and frame structures in the development of the Saab aircraft Viggen

    NASA Technical Reports Server (NTRS)

    Larsson, S. E.

    1972-01-01

    A part of the lower side of the main wing at the joint of the main spar with the fuselage frame was investigated. This wing beam area was simulated by a test specimen consisting of a spar boom of AZ 74 forging (7075 aluminum alloy modified with 0.3 percent Ag) and a portion of a honeycomb sandwich panel attached to the boom flange with steel bolts. The cross section was reduced to half scale. However, the flange thickness, the panel height, and the bolt size were full scale. Further, left and right portions of the fuselage frame intended to carry over the bending moment of the main wing were tested. Each of these frame halves consisted of a forward and a rear forging (7079 aluminum alloy, overaged) connected by an outer and inner skin (Alclad 7075) creating a box beam. These test specimens were full scale and were constructed principally of ordinary aircraft components. The test load spectrum was common to both types of specimens with regard to percentage levels. It consisted of maneuver and gust loads, touchdown loads, and loads due to ground roughness. A load history of 200 hours of flight with 15,000 load cycles was punched on a tape. The loads were randomized in groups according to the flight-by-flight principle. The highest positive load level was 90 percent of limit load and the largest negative load was -27 percent. A total of 20 load levels were used. Both types of specimens were provided with strain gages and had a nominal stress of about 300 MN/sq m in some local areas. As a result of the tests, steps were taken to reduce the risk of fatigue damage in aircraft. Thus stress levels were lowered, radii were increased, and demands on surface finish were sharpened.

  17. Ryan Flexwing aircraft under test

    NASA Technical Reports Server (NTRS)

    1962-01-01

    A flexible wing aircraft built by Ryan, was flown in the Full Scale Tunnel. The researcher posing as the pilot is John W. Paulson, Assistant Head of the Full Scale Tunnel. Photograph published in Sixty Years of Aeronautical Research 1917-1977, by David A. Anderton - NASA publication (page 60).

  18. Structural-acoustic coupling in aircraft fuselage structures

    NASA Technical Reports Server (NTRS)

    Mathur, Gopal P.; Simpson, Myles A.

    1992-01-01

    Results of analytical and experimental investigations of structural-acoustic coupling phenomenon in an aircraft fuselage are described. The structural and acoustic cavity modes of DC-9 fuselage were determined using a finite element approach to vibration analysis. Predicted structural and acoustic dispersion curves were used to determine possible occurrences of structural-acoustic coupling for the fuselage. An aft section of DC-9 aircraft fuselage, housed in an anechoic chamber, was used for experimental investigations. The test fuselage was excited by a shaker and vibration response and interior sound field were measured using accelerometer and microphone arrays. The wavenumber-frequency structural and cavity response maps were generated from the measured data. Analysis and interpretation of the spatial plots and wavenumber maps provided the required information on modal characteristics, fuselage response and structural-acoustic coupling.

  19. Adhesion testing of aircraft tires

    NASA Technical Reports Server (NTRS)

    Bobo, S. N.

    1983-01-01

    Adhesion testing appeared to offer a less burdensome alternative to replace some of the dynamometer tests. Accordingly, test results and data were requested from retreaders who had used adhesion testing.

  20. Challenges for the aircraft structural integrity program

    NASA Technical Reports Server (NTRS)

    Lincoln, John W.

    1994-01-01

    Thirty-six years ago the United States Air Force established the USAF Aircraft Structural Integrity Program (ASIP) because flight safety had been degraded by fatigue failures of operational aircraft. This initial program evolved, but has been stable since the issuance of MIL-STD-1530A in 1975. Today, the program faces new challenges because of a need to maintain aircraft longer in an environment of reduced funding levels. Also, there is increased pressure to reduce cost of the acquisition of new aircraft. It is the purpose of this paper to discuss the challenges for the ASIP and identify the changes in the program that will meet these challenges in the future.

  1. Critical joints in large composite aircraft structure

    NASA Technical Reports Server (NTRS)

    Nelson, W. D.; Bunin, B. L.; Hart-Smith, L. J.

    1983-01-01

    A program was conducted at Douglas Aircraft Company to develop the technology for critical structural joints of composite wing structure that meets design requirements for a 1990 commercial transport aircraft. The prime objective of the program was to demonstrate the ability to reliably predict the strength of large bolted composite joints. Ancillary testing of 180 specimens generated data on strength and load-deflection characteristics which provided input to the joint analysis. Load-sharing between fasteners in multirow bolted joints was computed by the nonlinear analysis program A4EJ. This program was used to predict strengths of 20 additional large subcomponents representing strips from a wing root chordwise splice. In most cases, the predictions were accurate to within a few percent of the test results. In some cases, the observed mode of failure was different than anticipated. The highlight of the subcomponent testing was the consistent ability to achieve gross-section failure strains close to 0.005. That represents a considerable improvement over the state of the art.

  2. Pneumatic system structure for circulation control aircraft

    NASA Technical Reports Server (NTRS)

    Krauss, Timothy A. (Inventor); Roman, Stephan (Inventor); Beurer, Robert J. (Inventor)

    1986-01-01

    A plenum for a circulation control rotor aircraft which surrounds the rotor drive shaft (18) and is so constructed that the top (32), outer (38) and bottom (36) walls through compressed air is admitted are fixed to aircraft structure and the inner wall (34) through which air passes to rotor blades (14) rotates with the drive shaft and rotor blades.

  3. Aircraft Radiation Shield Experiments--Preflight Laboratory Testing

    NASA Technical Reports Server (NTRS)

    Singleterry, Robert C., Jr.; Shinn, Judy L.; Wilson, John W.; Maiden, Donald L.; Thibeault, Sheila A.; Badavi, Francis F.; Conroy, Thomas; Braby, Leslie

    1999-01-01

    In the past, measurements onboard a research Boeing 57F (RB57-F) aircraft have demonstrated that the neutron environment within the aircraft structure is greater than that in the local external environment. Recent studies onboard Boeing 737 commercial flights have demonstrated cabin variations in radiation exposure up to 30 percent. These prior results were the basis of the present study to quantify the potential effects of aircraft construction materials on the internal exposures of the crew and passengers. The present study constitutes preflight measurements using an unmoderated Cf-252 fission neutron source to quantify the effects of three current and potential aircraft materials (aluminum, titanium, and graphite-epoxy composite) on the fast neutron flux. Conclusions about the effectiveness of the three selected materials for radiation shielding must wait until testing in the atmosphere is complete; however, it is clear that for shielding low-energy neutrons, the composite material is an improved shielding material over aluminum or titanium.

  4. 14 CFR 91.1041 - Aircraft proving and validation tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Aircraft proving and validation tests. 91... Ownership Operations Program Management § 91.1041 Aircraft proving and validation tests. (a) No program manager may permit the operation of an aircraft, other than a turbojet aircraft, for which two pilots...

  5. Airvolt Aircraft Electric Propulsion Test Stand

    NASA Technical Reports Server (NTRS)

    Samuel, Aamod; Lin, Yohan

    2015-01-01

    Development of an electric propulsion test stand that collects high-fidelity data of motor, inverter, and battery system efficiencies; thermal dynamics; and acoustics independent of manufacturer reported values will improve understanding of electric propulsion systems to be used in future aircraft. A buildup approach to this development reveals new areas of research and best practices in testing, and attempts to establish a standard for testing these systems.

  6. Electronic materials testing in commercial aircraft engines

    NASA Astrophysics Data System (ADS)

    Brand, Dieter

    A device for the electronic testing of materials used in commercial aircraft engines is described. The instrument can be used for ferromagnetic, ferrimagnetic, and nonferromagnetic metallic materials, and it functions either optically or acoustically. The design of the device is described and technical data are given. The device operates under the principle of controlled self-inductivity. Its mode of operation is described.

  7. Smart structure application for the Challenger aircraft

    NASA Astrophysics Data System (ADS)

    Grenier, L.; Blaha, Franz A.

    1994-09-01

    The Challenger aircraft fleet of the Canadian Forces will fly demanding missions, requiring the implementation of a fatigue management program based on the monitoring of in-flight aircraft load conditions. Conventional sensing techniques experience problems arising from severe electromagnetic interference (EMI). This paper describes the development of an EMI- insensitive smart-structure sensing concept for loads monitoring. Fiber-optic strain sensors, incorporated at critical structural locations, are used to monitor the fatigue life of the aircraft wing, fuselage, and empennage. A fiber-optic accelerometer is also incorporated in the system. A long-term plan is presented for the development of an advanced smart-structure concept which can support the continuous monitoring of fatigue-prone components, and provide the aircraft with near real-time damage location and assessment.

  8. 14 CFR 121.163 - Aircraft proving tests.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Aircraft proving tests. 121.163 Section 121... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Aircraft Requirements § 121.163 Aircraft proving...) Alterations to the aircraft or its components that materially affect flight characteristics. (e)...

  9. 14 CFR 121.163 - Aircraft proving tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Aircraft proving tests. 121.163 Section 121... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Aircraft Requirements § 121.163 Aircraft proving...) Alterations to the aircraft or its components that materially affect flight characteristics. (e)...

  10. 14 CFR 121.163 - Aircraft proving tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Aircraft proving tests. 121.163 Section 121... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Aircraft Requirements § 121.163 Aircraft proving...) Alterations to the aircraft or its components that materially affect flight characteristics. (e)...

  11. 14 CFR 121.163 - Aircraft proving tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Aircraft proving tests. 121.163 Section 121... REQUIREMENTS: DOMESTIC, FLAG, AND SUPPLEMENTAL OPERATIONS Aircraft Requirements § 121.163 Aircraft proving...) Alterations to the aircraft or its components that materially affect flight characteristics. (e)...

  12. Uncertain structural dynamics of aircraft panels and fuzzy structures analysis

    NASA Astrophysics Data System (ADS)

    Sparrow, Victor W.; Buehrle, Ralph D.

    2002-11-01

    Aircraft fuselage panels, seemingly simple structures, are actually complex because of the uncertainty of the attachments of the frame stiffeners and longitudinal stringers. It is clearly important to understand the dynamics of these panels because of the subsequent radiation into the passenger cabin, even when complete information is not available for all portions of the finite-element model. Over the last few years a fuzzy structures analysis (FSA) approach has been undertaken at Penn State and NASA Langley to quantify the uncertainty in modeling aircraft panels. A new MSC.Nastran [MSC.Software Corp. (Santa Ana, CA)] Direct Matrix Abstraction Program (DMAP) code was written and tested [AIAA paper 2001-1320, 42nd AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conf., Seattle, WA, 16 April 2001] and was applied to simple fuselage panel models [J. Acoust. Soc. Am. 109, 2410(A) (2001)]. Recently the work has focused on understanding the dynamics of a realistic aluminum fuselage panel, typical of today's aircraft construction. This presentation will provide an overview of the research and recent results will be given for the fuselage panel. Comparison between experiments and the FSA results will be shown for different fuzzy input parameters. [Work supported by NASA Research Cooperative Agreement NCC-1-382.

  13. Plastics as structural materials for aircraft

    NASA Technical Reports Server (NTRS)

    Kline, G M

    1937-01-01

    The purpose here is to consider the mechanical characteristics of reinforced phenol-formaldehyde resin as related to its use as structural material for aircraft. Data and graphs that have appeared in the literature are reproduced to illustrate the comparative behavior of plastics and materials commonly used in aircraft construction. Materials are characterized as to density, static strength, modulus of elasticity, resistance to long-time loading, strength under repeated impact, energy absorption, corrosion resistance, and ease of fabrication.

  14. Self Healing Composite for Aircraft's Structural Application

    NASA Astrophysics Data System (ADS)

    Teoh, S. H.; Chia, H. Y.; Lee, M. S.; Nasyitah, A. J. N.; Luqman, H. B. S. M.; Nurhidayah, S.; Tan, Willy. C. K.

    When one cuts himself, it is amazing to watch how quickly the body acts to mend the wound. Immediately, the body works to pull the skin around the cut back together. The concept of repair by bleeding of enclosed functional agents serves as the biomimetic inspiration of synthetic self repair systems. Such synthetic self repair systems are based on advancement in polymeric materials; the process of human thrombosis is the inspiration for the application of self healing fibres within the composite materials. Results based on flexural 3 point bend test on the prepared samples have shown that the doubled layer healed hollow fibre laminate subjected to a healing regime of 3 weeks has a healed strength increase of 27% compared to the damaged baseline laminate. These results gave us confidence that there is a great potential to adopt such self healing mechanism on actual composite parts like in aircraft's composite structures.

  15. 14 CFR 135.145 - Aircraft proving and validation tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Aircraft proving and validation tests. 135... Aircraft and Equipment § 135.145 Aircraft proving and validation tests. (a) No certificate holder may...) Validation testing is required to determine that a certificate holder is capable of conducting...

  16. 14 CFR 135.145 - Aircraft proving and validation tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Aircraft proving and validation tests. 135... Aircraft and Equipment § 135.145 Aircraft proving and validation tests. (a) No certificate holder may...) Validation testing is required to determine that a certificate holder is capable of conducting...

  17. Quantitative thermal imaging of aircraft structures

    NASA Astrophysics Data System (ADS)

    Cramer, K. Elliott; Howell, Patricia A.; Syed, Hazari I.

    1995-03-01

    Aircraft structural integrity is a major concern for airlines and airframe manufacturers. To remain economically competitive, airlines are looking at ways to retire older aircraft, not when some fixed number of flight hours or cycles has been reached, but when true structural need dictates. This philosophy is known as `retirement for cause.' The need to extend the life of commercial aircraft has increased the desire to develop nondestructive evaluation (NDE) techniques capable of detecting critical flaws such as disbonding and corrosion. These subsurface flaws are of major concern in bonded lap joints. Disbonding in such a joint can provide an avenue for moisture to enter the structure leading to corrosion. Significant material loss due to corrosion can substantially reduce the structural strength, load bearing capacity and ultimately reduce the life of the structure. The National Aeronautics and Space Administration's Langley Research Center has developed a thermal NDE system designed for application to disbonding and corrosion detection in aircraft skins. By injecting a small amount of heat into the front surface of an aircraft skin, and recording the time history of the resulting surface temperature variations using an infrared camera, quantitative images of both bond integrity and material loss due to corrosion can be produced. This paper presents a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. The analysis techniques presented represent a significant improvement in the information available over conventional thermal imaging due to the inclusion of data from both the heating and cooling portion of the thermal cycle. Results of laboratory experiments on fabricated disbond and material loss samples are presented to determine the limitations of the system. Additionally, the results of actual aircraft inspections are shown, which help to establish the field applicability for this

  18. Improving transient analysis technology for aircraft structures

    NASA Technical Reports Server (NTRS)

    Melosh, R. J.; Chargin, Mladen

    1989-01-01

    Aircraft dynamic analyses are demanding of computer simulation capabilities. The modeling complexities of semi-monocoque construction, irregular geometry, high-performance materials, and high-accuracy analysis are present. At issue are the safety of the passengers and the integrity of the structure for a wide variety of flight-operating and emergency conditions. The technology which supports engineering of aircraft structures using computer simulation is examined. Available computer support is briefly described and improvement of accuracy and efficiency are recommended. Improved accuracy of simulation will lead to a more economical structure. Improved efficiency will result in lowering development time and expense.

  19. Active Suppression Of Vibrations On Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Maestrello, Lucio

    1995-01-01

    Method of active suppression of nonlinear and nonstationary vibrations developed to reduce sonic fatigue and interior noise in high-speed aircraft. Structure of aircraft exhibits periodic, chaotic, and random vibrations when forced by high-intensity sound from jet engines, shock waves, turbulence, and separated flows. Method of suppressing vibrations involves feedback control: Strain gauges or other sensors mounted in paths of propagation of vibrations on structure sense vibrations; outputs of sensors processed into control signal applied to actuator mounted on structure, inducing compensatory forces.

  20. Wind-tunnel tests of the XV-15 tilt rotor aircraft

    NASA Technical Reports Server (NTRS)

    Weiberg, J. A.; Maisel, M. D.

    1980-01-01

    The XV-15 aircraft was tested in the Ames 40 by 80 Foot Wind Tunnel for preliminary evaluation of aerodynamic and aeroelastic characteristics prior to flight. The tests were undertaken to investigate the aircraft performance, stability, control and structural loads for flight modes from helicopter through transition and airplane mode up to the tunnel capability of 170 knots. Results from these tests are presented.

  1. Adaptive structures for fixed and rotary wing aircraft

    NASA Astrophysics Data System (ADS)

    Martin, Willi; Jänker, Peter; Siemetzki, Markus; Lorkowski, Thomas; Grohmann, Boris; Maier, Rudolf; Maucher, Christoph; Klöppel, Valentin; Enenkl, Bernhard; Roth, Dieter; Hansen, Heinz

    2007-07-01

    Since more than 10 years EADS Innovation Works, which is the corporate research centre of EADS (European Aeronautic Defence and Space Company), is investigating smart materials and adaptive structures for aircraft in cooperation with EADS business units. Focus of research efforts are adaptive systems for shape control, noise reduction and vibration control of both fixed and rotary wing aircraft as well as for lift optimisation of fixed wing aircraft. Two outstanding adaptive systems which have been pushed ahead in cooperation with Airbus Germany and Eurocopter Germany are adaptive servo flaps for helicopter rotor blades and innovative high lift devices for fixed wing aircraft which both were tested in flight for the first time representing world premieres. In this paper various examples of adaptive systems are presented which were developed and realized by EADS in recent years.

  2. Structural weight analysis of hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Ardema, M. D.

    1972-01-01

    The weights of major structural components of hypersonic, liquid hydrogen fueled aircraft are estimated and discussed. The major components are the body structure, body thermal protection system tankage and wing structure. The method of estimating body structure weight is presented in detail while the weights of the other components are estimated by methods given in referenced papers. Two nominal vehicle concepts are considered. The advanced concept employs a wing-body configuration and hot structure with a nonintegral tank, while the potential concept employs an all body configuration and cold, integral pillow tankage structure. Characteristics of these two concepts are discussed and parametric data relating their weight fractions to variations in vehicle shape and size design criteria and mission requirements, and structural arrangement are presented. Although the potential concept is shown to have a weight advantage over the advanced, it involves more design uncertainties since it is farther removed in design from existing aircraft.

  3. The influence of optical properties of paints and coatings on the efficiency of infrared nondestructive testing applied to aluminum aircraft structures

    NASA Astrophysics Data System (ADS)

    Burleigh, D.; Vavilov, V. P.; Pawar, S. S.

    2016-07-01

    IR NDT (Infrared Nondestructive Testing) is a popular method for detecting defects in composite, ceramic, and metallic structures. The effectiveness of IR NDT depends on various thermal and optical properties of the material being tested. The thermal properties, including thermal conductivity, thermal diffusivity, specific heat and density are important and have been discussed extensively in many treatises on IR NDT. However the optical properties of the surface are equally important and while the thermal properties cannot be changed, sometimes the optical properties can be. Bare metal surfaces have high reflectivities and low emissivities, and as a result, they are generally not good candidates for IR NDT. Painted, coated, anodized, and oxidized metal surfaces can, in some cases, be successfully tested with IR NDT, but the effectiveness depends on the optical properties of the surface. It is well known by IR NDT practitioners that the easy solution to the testing of reflective materials is to paint the surface black. However, this is not always practical and it may not be permitted by the "owner" of the part. This paper demonstrates a process of analyzing the interaction of spectral curves that are relevant to the IR NDT process. This process can be used to evaluate the effectiveness of an IR NDT process for use on real parts with specific coatings and can help select a coating that may improve the effectiveness. This paper shows examples of optical properties for some typical paints and coatings that may be used on aluminum aircraft structures. It shows the spectrum of a generic incandescent radiant heat source and how the energy from this source is absorbed by several of these paints. Further, it shows the interaction between an IR camera detector response curve and the other curves. And finally, it shows how these three can be combined to produce an "IR NDT" efficiency rating for several examples.

  4. Fire containment tests of aircraft interior panels

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Parker, J. A.; Leon, H. A.; Williamson, R. B.; Hasegawa, H.; Fisher, F.; Draemel, R.; Marcussen, W. H.; Hilado, C. J.

    1976-01-01

    The paper describes an experimental program carried out to evaluate a possible method for testing the fire-containment qualities of aircraft interior panels. The experimental apparatus consisted of a burner that simulates various fire loads under different ventilation conditions in an enclosure of approximately the same size as an aircraft lavatory module. Two fire-containment tests are discussed in which two adjoining walls of the enclosure were made from state-of-the-art composite panels; rats were exposed to the combustion products in order to evaluate the toxic threat posed by those products. The results show that the burner can be employed to represent various fire-load conditions and that the methodology developed for fire containment can be useful in evaluating the fire resistance of composite panels before conducting large-scale tests. It is concluded that elements of the fire-containment criteria include the temperature rise on the backface of the panels as a function of time, the flame burn-through by either decomposition or severe distortion of the material, and the toxicity of the combustion gases evolved.

  5. Aircraft empennage structural detail design

    NASA Technical Reports Server (NTRS)

    Lesnewski, David; Snow, Russ M.; Combs, Lisa M.; Paufler, David; Schnieder, George; Athousake, Roxanne

    1993-01-01

    The purpose of this project is to provide an empennage structural assembly that will withstand the operational loads defined in FAR Part 23, as well as those specified in the statement of work, i.e. snow, rain, humidity, tiedown forces, etc. The goal is to provide a simple yet durable lightweight structure that will transfer the aerodynamic forces produced by the tail surfaces through the most efficient load path to the airframe. The structure should be simple and cost-effective to manufacture and repair. All structures meet or exceed loading and fatigue criteria. The structure provides for necessary stiffness and ease of maintenance.

  6. Analysis and design technology for high-speed aircraft structures

    NASA Technical Reports Server (NTRS)

    Starnes, James H., Jr.; Camarda, Charles J.

    1992-01-01

    Recent high-speed aircraft structures research activities at NASA Langley Research Center are described. The following topics are covered: the development of analytical and numerical solutions to global and local thermal and structural problems, experimental verification of analysis methods, identification of failure mechanisms, and the incorporation of analysis methods into design and optimization strategies. The paper describes recent NASA Langley advances in analysis and design methods, structural and thermal concepts, and test methods.

  7. Flight Test of ASAC Aircraft Interior Noise Control System

    NASA Technical Reports Server (NTRS)

    Palumbo, Dan; Cabell, Ran; Cline, John; Sullivan, Brenda

    1999-01-01

    A flight test is described in which an active structural/acoustic control system reduces turboprop induced interior noise on a Raytheon Aircraft Company 1900D airliner. Control inputs to 21 inertial force actuators were computed adaptively using a transform domain version of the multichannel filtered-X LMS algorithm to minimize the mean square response of 32 microphones. A combinatorial search algorithm was employed to optimize placement of the force actuators on the aircraft frame. Both single frequency and multi-frequency results are presented. Reductions of up to 15 dB were obtained at the blade passage frequency (BPF) during single frequency control tests. Simultaneous reductions of the BPF and next 2 harmonics of 10 dB, 2.5 dB and 3.0 dB, were obtained in a multi-frequency test.

  8. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    SciTech Connect

    Moore, D.G.; Jones, C.R.; Mihelic, J.E.; Barnes, J.D.

    1998-08-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft`s right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in-flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft`s right main wheel fairing. Inspection results and techniques developed to verify the aircraft`s structural integrity are discussed.

  9. The design and testing of subscale smart aircraft wing bolts

    NASA Astrophysics Data System (ADS)

    Vugampore, J. M. V.; Bemont, C.

    2012-07-01

    Presently costly periodic inspection is vital in guaranteeing the structural integrity of aircraft. This investigation assesses the potential for significantly reducing aircraft maintenance costs without modification of aircraft structures by implementing smart wing bolts, manufactured from TRIP steel, which can be monitored for damage in situ. TRIP steels undergo a transformation from paramagnetic austenite to ferromagnetic martensite during deformation. Subscale smart aircraft wing bolts were manufactured from hot rolled TRIP steel. These wing bolts were used to demonstrate that washers incorporating embedded inductance coils can be utilized to measure the martensitic transformation occurring in the TRIP steel during bolt deformation. Early in situ warning of a critical bolt stress level was thereby facilitated, potentially reducing the costly requirement for periodic wing bolt removal and inspection. The hot rolled TRIP steels that were utilized in these subscale bolts do not however exhibit the mechanical properties required of wing bolt material. Thus warm rolled TRIP steel alloys were also investigated. The mechanical properties of the best warm rolled TRIP steel alloy tested almost matched those of AISI 4340. The warm rolled alloys were also shown to exhibit transformation before yield, allowing for earlier warning when overload occurs. Further work will be required relating to fatigue crack detection, environmental temperature fluctuation and more thorough material characterization. However, present results show that in situ early detection of wing bolt overload is feasible via the use of high alloy warm rolled TRIP steel wing bolts in combination with inductive sensor embedded washers.

  10. Low-Cost Composite Materials and Structures for Aircraft Applications

    NASA Technical Reports Server (NTRS)

    Deo, Ravi B.; Starnes, James H., Jr.; Holzwarth, Richard C.

    2003-01-01

    A survey of current applications of composite materials and structures in military, transport and General Aviation aircraft is presented to assess the maturity of composites technology, and the payoffs realized. The results of the survey show that performance requirements and the potential to reduce life cycle costs for military aircraft and direct operating costs for transport aircraft are the main reasons for the selection of composite materials for current aircraft applications. Initial acquisition costs of composite airframe components are affected by high material costs and complex certification tests which appear to discourage the widespread use of composite materials for aircraft applications. Material suppliers have performed very well to date in developing resin matrix and fiber systems for improved mechanical, durability and damage tolerance performance. The next challenge for material suppliers is to reduce material costs and to develop materials that are suitable for simplified and inexpensive manufacturing processes. The focus of airframe manufacturers should be on the development of structural designs that reduce assembly costs by the use of large-scale integration of airframe components with unitized structures and manufacturing processes that minimize excessive manual labor.

  11. Soil analyses and evaluations at the impact dynamics research facility for two full-scale aircraft crash tests

    NASA Technical Reports Server (NTRS)

    Cheng, R. Y. K.

    1977-01-01

    The aircraft structural crash behavior and occupant survivability for aircraft crashes on a soil surface was studied. The results of placement, compaction, and maintenance of two soil test beds are presented. The crators formed by the aircraft after each test are described.

  12. 14 CFR 91.1041 - Aircraft proving and validation tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft proving and validation tests. 91... Ownership Operations Program Management § 91.1041 Aircraft proving and validation tests. (a) No program... tests. However, pilot flight training may be conducted during the proving tests. (d) Validation...

  13. 14 CFR 91.1041 - Aircraft proving and validation tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Aircraft proving and validation tests. 91... Ownership Operations Program Management § 91.1041 Aircraft proving and validation tests. (a) No program... tests. However, pilot flight training may be conducted during the proving tests. (d) Validation...

  14. Aircraft fuel tank slosh and vibration test

    NASA Astrophysics Data System (ADS)

    Zimmermann, H.

    1981-12-01

    A dynamic qualification test for a subsonic and a supersonic external drop tank for a European fighter is presented. The test rig and the specimens are described and the measuring results are discussed. It is shown that for the supersonic tank as well as for the subsonic tank a certain slosh angle an eigenfrequency of the rig increases the amplitudes at the excitation position and the accelerations on the tank. For the subsonic tank it seems that an eigenfrequency is excited for the nose down position of the tank. The qualification requirements are examined. It is proposed that instead of using an arbitrary vibration amplitude and frequency for excitation, frequency ranges and amplitudes which are averaged out of flight measurements at the tank attachment points on the aircraft be used and that the demand for a certain input amplitude at the top of the attachment bulkheads and an output amplitude at the bottom of the attachment bulkheads be deleted.

  15. Active Structural Control for Aircraft Efficiency with the X-56A Aircraft

    NASA Technical Reports Server (NTRS)

    Ouellette, Jeffrey

    2015-01-01

    The X-56A Multi-Utility Technology Testbed is an experimental aircraft designed to study active control of flexible structures. The vehicle is easily reconfigured to allow for testing of different configurations. The vehicle is being used to study new sensor, actuator, modeling and controls technologies. These new technologies will allow for lighter vehicles and new configurations that exceed the efficiency currently achievable. A description of the vehicle and the current research efforts that it enables are presented.

  16. Structural analysis at aircraft conceptual design stage

    NASA Astrophysics Data System (ADS)

    Mansouri, Reza

    In the past 50 years, computers have helped by augmenting human efforts with tremendous pace. The aircraft industry is not an exception. Aircraft industry is more than ever dependent on computing because of a high level of complexity and the increasing need for excellence to survive a highly competitive marketplace. Designers choose computers to perform almost every analysis task. But while doing so, existing effective, accurate and easy to use classical analytical methods are often forgotten, which can be very useful especially in the early phases of the aircraft design where concept generation and evaluation demands physical visibility of design parameters to make decisions [39, 2004]. Structural analysis methods have been used by human beings since the very early civilization. Centuries before computers were invented; the pyramids were designed and constructed by Egyptians around 2000 B.C, the Parthenon was built by the Greeks, around 240 B.C, Dujiangyan was built by the Chinese. Persepolis, Hagia Sophia, Taj Mahal, Eiffel tower are only few more examples of historical buildings, bridges and monuments that were constructed before we had any advancement made in computer aided engineering. Aircraft industry is no exception either. In the first half of the 20th century, engineers used classical method and designed civil transport aircraft such as Ford Tri Motor (1926), Lockheed Vega (1927), Lockheed 9 Orion (1931), Douglas DC-3 (1935), Douglas DC-4/C-54 Skymaster (1938), Boeing 307 (1938) and Boeing 314 Clipper (1939) and managed to become airborne without difficulty. Evidencing, while advanced numerical methods such as the finite element analysis is one of the most effective structural analysis methods; classical structural analysis methods can also be as useful especially during the early phase of a fixed wing aircraft design where major decisions are made and concept generation and evaluation demands physical visibility of design parameters to make decisions

  17. XV-15 Tiltrotor Aircraft: 1997 Acoustic Testing

    NASA Technical Reports Server (NTRS)

    Edwards, Bryan D.; Conner, David A.

    2003-01-01

    XV-15 acoustic test is discussed, and measured results are presented. The test was conducted by NASA Langley and Bell Helicopter Textron, Inc., during June - July 1997, at the BHTI test site near Waxahachie, Texas. This was the second in a series of three XV-15 tests to document the acoustic signature of the XV-15 tiltrotor aircraft for a variety of flight conditions and minimize the noise signature during approach. Tradeoffs between flight procedures and the measured noise are presented to illustrate the noise abatement flight procedures. The test objectives were to: (1) support operation of future tiltrotors by further developing and demonstrating low-noise flight profiles, while maintaining acceptable handling and ride qualities, and (2) refine approach profiles, selected from previous (1995) tiltrotor testing, to incorporate Instrument Flight Rules (IFR), handling qualities constraints, operations and tradeoffs with sound. Primary emphasis was given to the approach flight conditions where blade-vortex interaction (BVI) noise dominates, because this condition influences community noise impact more than any other. An understanding of this part of the noise generating process could guide the development of low noise flight operations and increase the tiltrotor's acceptance in the community.

  18. Measurement of surface scratches on aircraft structures

    NASA Astrophysics Data System (ADS)

    Sarr, Dennis P.

    1996-01-01

    In assuring the quality of aircraft, the skin quality must be free of surface imperfections. Surface imperfections such as scratches are unacceptable for cosmetic and structural reasons. Scratches beyond a certain depth are not repairable, resulting in costly replacement of an aircraft's part. Measurements of aircraft exterior surfaces require a ladder or cherry picker for positioning the inspector. Commercially-available computer vision systems are not portable, easy to use, or ergonomic. The machine vision system must be designed with these criteria in mind. The scratch measurement system (SMS) uses computer vision, digital signal processing, and automated inspection methods. The system is portable and battery powered. It is certified for measuring the depth and width of the anomaly. The SMS provides a comprehensive, analytical, and accurate reading. A hardcopy output provides a permanent record of the analysis. The graphical data shows the surface profile and provides substantial information of the surface anomaly. The factory and flight line use the SMS at different stages of aircraft production. Six systems have been built for use within Boeing. A patent was issued for the SMS in February 1994.

  19. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  20. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.

  1. High speed wind tunnel tests of the PTA aircraft. [Propfan Test Assessment Program

    NASA Technical Reports Server (NTRS)

    Aljabri, A. S.; Little, B. H., Jr.

    1986-01-01

    Propfans, advanced highly-loaded propellers, are proposed to power transport aircraft that cruise at high subsonic speeds, giving significant fuel savings over the equivalent turbofan-powered aircraft. NASA is currently sponsoring the Propfan Test Assessment Program (PTA) to provide basic data on the structural integrity and acoustic performance of the propfan. The program involves installation design, wind-tunnel tests, and flight tests of the Hamilton Standard SR-7 propfan in a wing-mount tractor installation on the Gulfstream II aircraft. This paper reports on the high-speed wind-tunnel tests and presents the computational aerodynamic methods that were employed in the analyses, design, and evaluation of the configuration. In spite of the complexity of the configuration, these methods provide aerodynamic predictions which are in excellent agreement with wind-tunnel data.

  2. Rotor systems research aircraft airplane configuration flight-test results

    NASA Technical Reports Server (NTRS)

    Painter, W. D.; Erickson, R. E.

    1984-01-01

    The rotor systems research aircraft (RSRA) has undergone ground and flight tests, primarily as a compound aircraft. The purpose was to train pilots and to check out and develop the design flight envelope. The preparation and flight test of the RSRA in the airplane, or fixed-wind, configuration are reviewed and the test results are discussed.

  3. NASA service experience with composite components. [for aircraft structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.; Chapman, A. J.

    1980-01-01

    NASA Langley has been active in sponsoring flight service programs with advanced composites during the past decade. A broad data base and confidence in the durability of composite structures are being developed. Flight service experience is reported for more than 140 composite aircraft components with up to 8 years service and almost two million successful component flight hours. Composite components are being evaluated on Boeing, Douglas, and Lockheed transport aircraft. Components are currently under development for service evaluation on Bell and Sikorsky helicopters. Design concepts and inspection and maintenance results are reported for components currently in service. Components under development in the NASA Aircraft Energy Efficiency (ACEE) program are discussed. Results of flight, outdoor ground, and controlled laboratory environmental tests on composite materials used in the flight service programs are also presented.

  4. Structural health management for aging aircraft

    NASA Astrophysics Data System (ADS)

    Ikegami, Roy; Haugse, Eric D.

    2001-06-01

    An effective structural health management (SHM) system can be a useful tool for making aircraft fleet management decisions ranging from individual aircraft maintenance scheduling and usage restrictions to fleet rotation strategies. This paper discusses the end-user requirements for the elements and architecture of an effective SHM system for application to both military and commercial aging aircraft fleets. The elements discussed include the sensor systems for monitoring and characterizing the health of the structure, data processing methods for interpreting sensor data and converting it into useable information, and automated methods for erroneous data detection, data archiving and information dissemination. Current and past SHM technology development/maturation efforts in these areas at the Boeing Company will be described. An evolutionary technology development strategy is developed in which the technologies needed will be matured, integrated into a vehicle health management system, and benefits established without requiring extensive changes to the end-user's existing operation and maintenance infrastructure. Issues regarding the end-user customer acceptance of SHM systems are discussed and summarized.

  5. Interior noise control ground test studies for advanced turboprop aircraft applications

    NASA Technical Reports Server (NTRS)

    Simpson, Myles A.; Cannon, Mark R.; Burge, Paul L.; Boyd, Robert P.

    1989-01-01

    The measurement and analysis procedures are documented, and the results of interior noise control ground tests conducted on a DC-9 aircraft test section are summarized. The objectives of these tests were to study the fuselage response characteristics of treated and untreated aircraft with aft-mount advanced turboprop engines and to analyze the effectiveness of selected noise control treatments in reducing passenger cabin noise on these aircraft. The results of fuselage structural mode surveys, cabin cavity surveys and sound intensity surveys are presented. The performance of various structural and cabin sidewall treatments is assessed, based on measurements of the resulting interior noise levels under simulated advanced turboprop excitation.

  6. Technology of civil usage of composites. [in commercial aircraft structures

    NASA Technical Reports Server (NTRS)

    Kemp, D. E.

    1977-01-01

    The paper deals with the use of advanced composites in structural components of commercial aircraft. The need for testing the response of a material system to service environment is discussed along with methods for evaluating design and manufacturing aspects of a built-up structure under environmental conditions and fail-safe (damage-tolerance) evaluation of structures. Crashworthiness aspects, the fire-hazard potential, and electrical damage of composite structures are considered. Practical operational experience with commercial aircraft is reviewed for boron/epoxy foreflaps, Kevlar/epoxy fillets and fairings, graphite/epoxy spoilers, graphite/polysulfone spoilers, graphite/epoxy floor posts, boron/aluminum aft pylon skin panels, graphite/epoxy engine nose cowl outer barrels, and graphite/epoxy upper aft rudder segments.

  7. Scatter factor and reliability of aircraft structures

    NASA Technical Reports Server (NTRS)

    Schueller, G. I.; Freudenthal, A. M.

    1972-01-01

    The concept of time to first failure is utilized to perform a parameter study of scatter factors of aircraft structures. The Weibull distribution is used for estimation of characteristic and certifiable lives. Scatter factors for various Weibull-shaped parameters, fleet sizes and level of reliabilities are calculated. It is concluded that the currently used range of scatter factors (2 through 4) is too narrow for the estimation of a safe life and that a safe and economical design for structural materials with shape parameters less than 2 does not seem feasible except for very small fleet sizes and low levels of reliability.

  8. Service evaluation of aircraft composite structural components

    NASA Technical Reports Server (NTRS)

    Brooks, W. A., Jr.; Dow, M. B.

    1973-01-01

    The advantages of the use of composite materials in structural applications have been identified in numerous engineering studies. Technology development programs are underway to correct known deficiencies and to provide needed improvements. However, in the final analysis, flight service programs are necessary to develop broader acceptance of, and confidence in, any new class of materials such as composites. Such flight programs, initiated by NASA Langley Research Center, are reviewed. These programs which include the selectively reinforced metal and the all-composite concepts applied to both secondary and primary aircraft structural components, are described and current status is indicated.

  9. 77 FR 14319 - Unmanned Aircraft System Test Sites

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-09

    ... can be found in the Federal Register published on April 11, 2000 (65 FR 19477-19478), as well as at... Federal Aviation Administration 14 CFR Part 91 Unmanned Aircraft System Test Sites AGENCY: Federal... test ranges/sites to integrate unmanned aircraft systems (UAS) into the National Airspace System...

  10. Flight test of ARINC 741 configuration low gain SATCOM system on Boeing 747-400 aircraft

    NASA Astrophysics Data System (ADS)

    Murphy, Timothy A.; Stapleton, Brian P.

    The Boeing company conducted a flight test of a SATCOM system similar to the ARINC 741 configuration on a production model 747-400. A flight plan was specifically designed to test the system over a wide variety of satellite elevations and aircraft attitudes as well as over land and sea. Interface bit errors, signal quality and aircraft position and navigational inputs were all recorded as a function of time. Special aircraft maneuvers were performed to demonstrate the potential for shadowing by aircraft structures. Both a compass rose test and the flight test indicated that shadowing from the tail is insignificant for the 747-400. However, satellite elevation angles below the aircraft horizon during banking maneuvers were shown to have a significant deleterious effect on SATCOM communications.

  11. Flight test of ARINC 741 configuration low gain SATCOM system on Boeing 747-400 aircraft

    NASA Technical Reports Server (NTRS)

    Murphy, Timothy A.; Stapleton, Brian P.

    1990-01-01

    The Boeing company conducted a flight test of a SATCOM system similar to the ARINC 741 configuration on a production model 747-400. A flight plan was specifically designed to test the system over a wide variety of satellite elevations and aircraft attitudes as well as over land and sea. Interface bit errors, signal quality and aircraft position and navigational inputs were all recorded as a function of time. Special aircraft maneuvers were performed to demonstrate the potential for shadowing by aircraft structures. Both a compass rose test and the flight test indicated that shadowing from the tail is insignificant for the 747-400. However, satellite elevation angles below the aircraft horizon during banking maneuvers were shown to have a significant deleterious effect on SATCOM communications.

  12. Structural properties of impact ices accreted on aircraft structures

    NASA Technical Reports Server (NTRS)

    Scavuzzo, R. J.; Chu, M. L.

    1987-01-01

    The structural properties of ice accretions formed on aircraft surfaces are studied. The overall objectives are to measure basic structural properties of impact ices and to develop finite element analytical procedures for use in the design of all deicing systems. The Icing Research Tunnel (IRT) was used to produce simulated natural ice accretion over a wide range of icing conditions. Two different test apparatus were used to measure each of the three basic mechanical properties: tensile, shear, and peeling. Data was obtained on both adhesive shear strength of impact ices and peeling forces for various icing conditions. The influences of various icing parameters such as tunnel air temperature and velocity, icing cloud drop size, material substrate, surface temperature at ice/material interface, and ice thickness were studied. A finite element analysis of the shear test apparatus was developed in order to gain more insight in the evaluation of the test data. A comparison with other investigators was made. The result shows that the adhesive shear strength of impact ice typically varies between 40 and 50 psi, with peak strength reaching 120 psi and is not dependent on the kind of substrate used, the thickness of accreted ice, and tunnel temperature below 4 C.

  13. Self Diagnostic Accelerometer Testing on the C-17 Aircraft

    NASA Technical Reports Server (NTRS)

    Tokars, Roger P.; Lekki, John D.

    2013-01-01

    The self diagnostic accelerometer (SDA) developed by the NASA Glenn Research Center was tested for the first time in an aircraft engine environment as part of the Vehicle Integrated Propulsion Research (VIPR) program. The VIPR program includes testing multiple critical flight sensor technologies. One such sensor, the accelerometer, measures vibrations to detect faults in the engine. In order to rely upon the accelerometer, the health of the accelerometer must be ensured. The SDA is a sensor system designed to actively determine the accelerometer structural health and attachment condition, in addition to vibration measurements. The SDA uses a signal conditioning unit that sends an electrical chirp to the accelerometer and recognizes changes in the response due to changes in the accelerometer health and attachment condition. To demonstrate the SDAs flight worthiness and robustness, multiple SDAs were mounted and tested on a C-17 aircraft engine. The engine test conditions varied from engine off, to idle, to maximum power. The SDA attachment conditions were varied from fully tight to loose. The newly developed SDA health algorithm described herein uses cross correlation pattern recognition to discriminate a healthy from a faulty SDA. The VIPR test results demonstrate for the first.

  14. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Jones, C. R.; Mihelic, J. E.; Barnes, J. D.

    1998-01-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft's right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in- flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft's right main wheel fairing. Inspection results and techniques developed to verify the aircraft's structural integrity are discussed.

  15. Nde of Bonded Aluminum Components on Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Barnard, Daniel J.; Hsu, David K.; Foreman, Cory; Wendt, Scott; Kreitinger, Nicholas A.; Steffes, Gary J.

    2008-02-01

    Bonded aluminum structures have been commonly used on aircraft for many years, and many of these applications include flight control surfaces. These bonded structures can be made up of aluminum face sheets adhesively bonded to a central honeycomb core, or they could also be composed of machined components that are bonded in a tongue-in-groove type manner called Grid-Lock. Nondestructive Inspection (NDI) methods of bonded aluminum structures usually involve the detection of skin-to-core disbonds, core buckling and damage caused by impacts. In the case of Grid-Lock, NDI techniques are focused on the detection of failures in the tongue-in-groove adhesive joint. Three nondestructive inspection methods were applied to honeycomb sandwich structures and Grid-Lock panels. The three methods were computer aided tap test (CATT), air-coupled ultrasonic testing (ACUT), and mechanical impedance analysis (MIA). The honeycomb structures tested consisted of structural panels and flight control surfaces from various aircraft. The Grid-Lock samples tested are laboratory specimens that simulate various defects. Experimental results and comparisons from each of these methods and samples will be presented.

  16. 14 CFR 21.128 - Tests: aircraft engines.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tests: aircraft engines. 21.128 Section 21... engines. (a) Each person manufacturing aircraft engines under a type certificate only shall subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to...

  17. 14 CFR 21.128 - Tests: aircraft engines.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Tests: aircraft engines. 21.128 Section 21... engines. (a) Each person manufacturing aircraft engines under a type certificate must subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to an...

  18. 14 CFR 21.128 - Tests: aircraft engines.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tests: aircraft engines. 21.128 Section 21... engines. (a) Each person manufacturing aircraft engines under a type certificate only shall subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to...

  19. Fracture control procedures for aircraft structural integrity

    NASA Technical Reports Server (NTRS)

    Wood, H. A.

    1972-01-01

    The application of applied fracture mechanics in the design, analysis, and qualification of aircraft structural systems are reviewed. Recent service experiences are cited. Current trends in high-strength materials application are reviewed with particular emphasis on the manner in which fracture toughness and structural efficiency may affect the material selection process. General fracture control procedures are reviewed in depth with specific reference to the impact of inspectability, structural arrangement, and material on proposed analysis requirements for safe crack growth. The relative impact on allowable design stress is indicated by example. Design criteria, material, and analysis requirements for implementation of fracture control procedures are reviewed together with limitations in current available data techniques. A summary of items which require further study and attention is presented.

  20. Design and flight test of the Propulsion Controlled Aircraft (PCA) flight control system on the NASA F-15 test aircraft

    NASA Technical Reports Server (NTRS)

    Wells, Edward A.; Urnes, James M., Sr.

    1994-01-01

    This report describes the design, development and flight testing of the Propulsion Controlled Aircraft (PCA) flight control system performed at McDonnell Douglas Aerospace (MDA), St. Louis, Missouri and at the NASA Dryden Flight Research Facility, Edwards Air Force Base, California. This research and development program was conducted by MDA and directed by NASA through the Dryden Flight Research Facility for the period beginning January 1991 and ending December 1993. A propulsion steering backup to the aircraft conventional flight control system has been developed and flight demonstrated on a NASA F-15 test aircraft. The Propulsion Controlled Aircraft (PCA) flight system utilizes collective and differential thrust changes to steer an aircraft that experiences partial or complete failure of the hydraulically actuated control surfaces. The PCA flight control research has shown that propulsion steering is a viable backup flight control mode and can assist the pilot in safe landing recovery of a fighter aircraft that has damage to or loss of the flight control surfaces. NASA, USAF and Navy evaluation test pilots stated that the F-15 PCA design provided the control necessary to land the aircraft. Moreover, the feasibility study showed that PCA technology can be directly applied to transport aircraft and provide a major improvement in the survivability of passengers and crew of controls damaged aircraft.

  1. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Astrophysics Data System (ADS)

    Ennix, Kimberly A.

    1994-02-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  2. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Technical Reports Server (NTRS)

    Ennix, Kimberly A.

    1993-01-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  3. Engine exhaust characteristics evaluation in support of aircraft acoustic testing

    NASA Technical Reports Server (NTRS)

    Ennix, Kimberly A.

    1994-01-01

    NASA Dryden Flight Research Facility and NASA Langley Research Center completed a joint acoustic flight test program. Test objectives were (1) to quantify and evaluate subsonic climb-to-cruise noise and (2) to obtain a quality noise database for use in validating the Aircraft Noise Prediction Program. These tests were conducted using aircraft with engines that represent the high nozzle pressure ratio of future transport designs. Test flights were completed at subsonic speeds that exceeded Mach 0.3 using F-18 and F-16XL aircraft. This paper describes the efforts of NASA Dryden Flight Research Facility in this flight test program. Topics discussed include the test aircraft, setup, and matrix. In addition, the engine modeling codes and nozzle exhaust characteristics are described.

  4. The potential of small unmanned aircraft systems and structure-from-motion for topographic surveys: A test of emerging integrated approaches at Cwm Idwal, North Wales

    NASA Astrophysics Data System (ADS)

    Tonkin, T. N.; Midgley, N. G.; Graham, D. J.; Labadz, J. C.

    2014-12-01

    Novel topographic survey methods that integrate both structure-from-motion (SfM) photogrammetry and small unmanned aircraft systems (sUAS) are a rapidly evolving investigative technique. Due to the diverse range of survey configurations available and the infancy of these new methods, further research is required. Here, the accuracy, precision and potential applications of this approach are investigated. A total of 543 images of the Cwm Idwal moraine-mound complex were captured from a light (< 5 kg) semi-autonomous multi-rotor unmanned aircraft system using a consumer-grade 18 MP compact digital camera. The images were used to produce a DSM (digital surface model) of the moraines. The DSM is in good agreement with 7761 total station survey points providing a total vertical RMSE value of 0.517 m and vertical RMSE values as low as 0.200 m for less densely vegetated areas of the DSM. High-precision topographic data can be acquired rapidly using this technique with the resulting DSMs and orthorectified aerial imagery at sub-decimetre resolutions. Positional errors on the total station dataset, vegetation and steep terrain are identified as the causes of vertical disagreement. Whilst this aerial survey approach is advocated for use in a range of geomorphological settings, care must be taken to ensure that adequate ground control is applied to give a high degree of accuracy.

  5. Aircraft fatigue failures and tasks of structural reliability analysis

    NASA Astrophysics Data System (ADS)

    Fujiwara, Genkichi

    The aircraft structural inspection pattern and the statistical method of the structural fatigue life prediction are presented. The problems of the aircraft structural life span and the evaluation of fatigue strength are discussed, such as out of plane bending and deformation, and multiple site damage (MSD). The crack data of Boeing 747 section 41 upper deck frame and stringer is listed.

  6. Overview of computational structural methods for modern military aircraft

    NASA Technical Reports Server (NTRS)

    Kudva, J. N.

    1992-01-01

    Computational structural methods are essential for designing modern military aircraft. This briefing deals with computational structural methods (CSM) currently used. First a brief summary of modern day aircraft structural design procedures is presented. Following this, several ongoing CSM related projects at Northrop are discussed. Finally, shortcomings in this area, future requirements, and summary remarks are given.

  7. Actively cooled plate fin sandwich structural panels for hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Smith, L. M.; Beuyukian, C. S.

    1979-01-01

    An unshielded actively cooled structural panel was designed for application to a hypersonic aircraft. The design was an all aluminum stringer-stiffened platefin sandwich structure which used a 60/40 mixture of ethylene glycol/water as the coolant. Eight small test specimens of the basic platefin sandwich concept and three fatigue specimens from critical areas of the panel design was fabricated and tested (at room temperature). A test panel representative of all features of the panel design was fabricated and tested to determine the combined thermal/mechanical performance and structural integrity of the system. The overall findings are that; (1) the stringer-stiffened platefin sandwich actively cooling concept results in a low mass design that is an excellent contender for application to a hypersonic vehicle, and (2) the fabrication processes are state of the art but new or modified facilities are required to support full scale panel fabrication.

  8. Aircraft structural health monitoring using on-board BOCDA system

    NASA Astrophysics Data System (ADS)

    Yari, Takashi; Nagai, Kanehiro; Ishioka, Masahito; Hotate, Kazuo; Koshioka, Yasuhiro

    2008-03-01

    We developed the on-board BOCDA system for airplane and verified the flight environmental stability and durability through environmental test. The on-board BOCDA system adopted the polarization diversity technique and temporal gating technique to improve robustness of the BOCDA system. We successfully measured distribution of fiber Brillouin gain spectrum over 500m measurement range with 50mm spatial resolution, 60Hz sampling rate and +/-13μ strain accuracy. Furthermore, we considered flight test to verify the validity of the BOCDA system. From these results, it was confirmed that BOCDA system has potential to be applied to an aircraft structure health monitoring system.

  9. Survey of aircraft subcritical flight flutter testing methods

    NASA Technical Reports Server (NTRS)

    Rosenbaum, R.

    1974-01-01

    The results of a survey of U. S., British and French subcritical aircraft flight flutter testing methods are presented and evaluation of the applicability of these methods to the testing of the space shuttle are discussed. Ten U. S. aircraft programs covering the large civil transport aircraft and a variety of military aircraft are reviewed. In addition, three major French and British programs are covered by the survey. The significant differences between the U. S., French and British practices in the areas of methods of excitation, data acquisition, transmission and analysis are reviewed. The effect of integrating the digital computer into the flight flutter test program is discussed. Significant saving in analysis and flight test time are shown to result from the use of special digital computer routines and digital filters.

  10. The Altitude Laboratory for the Test of Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Dickinson, H C; Boutell, H G

    1920-01-01

    Report presents descriptions, schematics, and photographs of the altitude laboratory for the testing of aircraft engines constructed at the Bureau of Standards for the National Advisory Committee for Aeronautics.

  11. Identification of Aircraft Tubing by Rockwell Test

    NASA Technical Reports Server (NTRS)

    Knerr, Horace C.

    1930-01-01

    Seamless steel tubing is today the principal material of construction for aircraft. The commercial grade of tubing containing about 0.10 to 0.20% carbon at first used is being superseded by two grades which are approved by the army and navy, and which are also becoming standard for commercial airplanes.

  12. Structural health monitoring and impact detection for primary aircraft structures

    NASA Astrophysics Data System (ADS)

    Kosters, Eric; van Els, Thomas J.

    2010-04-01

    The increasing use of thermoplastic carbon fiber-reinforced plastic (CFRP) materials in the aerospace industry for primary aircraft structures, such as wing leading-edge surfaces and fuselage sections, has led to rapid growth in the field of structural health monitoring (SHM). Impact, vibration, and load can all cause failure, such as delamination and matrix cracking, in composite materials. Moreover, the internal material damage can occur without being visible to the human eye, making inspection of and clear insight into structural integrity difficult using currently available evaluation methods. Here, we describe the detection of impact and its localization in materials and structures by high-speed interrogation of multiple-fiber Bragg grating (FBG) sensors mounted on a composite aircraft component.

  13. XV-15 Tiltrotor Aircraft: 1999 Acoustic Testing - Test Report

    NASA Technical Reports Server (NTRS)

    Edwards, Bryan D.; Conner, David A.

    2003-01-01

    An XV-15 acoustic test is discussed, and measured results are presented. The test was conducted by NASA Langley and Bell Helicopter Textron, Inc., during October 1999, at the BHTI test site near Waxahachie, Texas. As part of the NASA-sponsored Short Haul Civil Tiltrotor noise reduction initiative, this was the third in a series of three major XV-15 acoustic tests. Their purpose was to document the acoustic signature of the XV-15 tiltrotor aircraft for a variety of flight conditions and to minimize the noise signature during approach. Tradeoffs between flight procedures and the measured noise are presented to illustrate the noise abatement flight procedures. The test objectives were to support operation of future tiltrotors by further developing and demonstrating low-noise flight profiles, while maintaining acceptable handling and ride qualities, and refine approach profiles, selected from previous (1995 & 1997) tiltrotor testing, to incorporate Instrument Flight Rules (IFR), handling qualities constraints, operations and tradeoffs with sound. Primary emphasis was given to the approach flight conditions where blade-vortex interaction (BVI) noise dominates, because this condition influences community noise impact more than any other. An understanding of this part of the noise generating process could guide the development of low noise flight operations and increase the tiltrotor's acceptance in the community.

  14. Flight flutter testing of multi-jet aircraft

    NASA Technical Reports Server (NTRS)

    Bartley, J.

    1975-01-01

    Extensive flight flutter tests were conducted by BAC on B-52 and KC-135 prototype airplanes. The need for and importance of these flight flutter programs to Boeing airplane design are discussed. Basic concepts of flight flutter testing of multi-jet aircraft and analysis of the test data will be presented. Exciter equipment and instrumentation employed in these tests will be discussed.

  15. Finite Element Model Development and Validation for Aircraft Fuselage Structures

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Fleming, Gary A.; Pappa, Richard S.; Grosveld, Ferdinand W.

    2000-01-01

    The ability to extend the valid frequency range for finite element based structural dynamic predictions using detailed models of the structural components and attachment interfaces is examined for several stiffened aircraft fuselage structures. This extended dynamic prediction capability is needed for the integration of mid-frequency noise control technology. Beam, plate and solid element models of the stiffener components are evaluated. Attachment models between the stiffener and panel skin range from a line along the rivets of the physical structure to a constraint over the entire contact surface. The finite element models are validated using experimental modal analysis results. The increased frequency range results in a corresponding increase in the number of modes, modal density and spatial resolution requirements. In this study, conventional modal tests using accelerometers are complemented with Scanning Laser Doppler Velocimetry and Electro-Optic Holography measurements to further resolve the spatial response characteristics. Whenever possible, component and subassembly modal tests are used to validate the finite element models at lower levels of assembly. Normal mode predictions for different finite element representations of components and assemblies are compared with experimental results to assess the most accurate techniques for modeling aircraft fuselage type structures.

  16. Structure-borne noise estimates for the PTA aircraft

    NASA Technical Reports Server (NTRS)

    Unruh, James F.

    1990-01-01

    Estimates of the level of in-flight structure-borne noise transmission in the Propfan Test Assessment Aircraft were carried out for the first three blade passage frequencies. The procedure used combined the frequency response functions of wing strain to cabin sound pressure level (SPL) response obtained during ground test with in-flight measured wing strain response data. The estimated cabin average in-flight structure-borne noise levels varied from 64 to 84 dB, with an average level of 74 dB. The estimates showed little dependence on engine/propeller power, flight altitude, or flight Mach number. In general, the bare cabin noise levels decreased with increasing propeller tone, giving rise to a plausible structure-borne noise transmission problem at the higher blade passage tones. Without knowledge of the effects of a high insertion loss side wall treatment on structure-borne noise transmission, no quantitative conclusions could be made.

  17. Analysis and testing of aeroelastic model stability augmentation systems. [for supersonic transport aircraft wing and B-52 aircraft control system

    NASA Technical Reports Server (NTRS)

    Sevart, F. D.; Patel, S. M.

    1973-01-01

    Testing and evaluation of a stability augmentation system for aircraft flight control were performed. The flutter suppression system and synthesis conducted on a scale model of a supersonic wing for a transport aircraft are discussed. Mechanization and testing of the leading and trailing edge surface actuation systems are described. The ride control system analyses for a 375,000 pound gross weight B-52E aircraft are presented. Analyses of the B-52E aircraft maneuver load control system are included.

  18. Mechanical paint removal techniques for aircraft structures

    NASA Astrophysics Data System (ADS)

    Amro, J. P.

    1989-12-01

    Paint removal was studied by mechanical means, i.e., blasting, from aluminum structural aeronautical materials (2024-T3) and the changes on the surface morphology introduced by the paint removal process are examined. The principal experimental parameters are particle velocity, and particle angle of incidence. An ideal combination of these parameters could yield a stripped aircraft skin substrate with minimal or no damage. Three types of plastic particles were used are: Polyextra, Polyplus, and Type III. Scanning electron microscopy has shown that a potentially damaging surface morphology is formed on the surface of the structural material. Multiple microcracks or fissures generated by the stripping could reduce the life and/or change the engineering properties of the material. It as also found that aluminum material stripped using plastic media particles has a very rough surface that may affect the aerodynamic flow of an airplane. The number of microcracks and degree of surface roughness vary with the particle impact angle and velocity. To minimize or eliminate the damage done to the surface during the plastic particle stripping, it was necessary to change the blasting media to softer and smaller particles. Commercial wheat flour was selected for this purpose. With the substitution of these natural particles, the scanning electron microscopy observations of the stripped surface revealed no potential damage (microcracks or fissures) on the structural material, and the surface roughness was also reduced.

  19. Development of stitched/RTM primary structures for transport aircraft

    NASA Technical Reports Server (NTRS)

    Hawley, Arthur V.

    1993-01-01

    This report covers work accomplished in the Innovative Composite Aircraft Primary Structure (ICAPS) program. An account is given of the design criteria and philosophy that guides the development. Wing and fuselage components used as a baseline for development are described. The major thrust of the program is to achieve a major cost breakthrough through development of stitched dry preforms and resin transfer molding (RTM), and progress on these processes is reported. A full description is provided on the fabrication of the stitched RTM wing panels. Test data are presented.

  20. Fly-by-light aircraft closed loop test program

    NASA Astrophysics Data System (ADS)

    Halski, Don J.; Kessler, Bradley L.; Mattes, Robert E.; Wanamaker, Michael F.; Baumbick, Robert J.

    1995-05-01

    The Fly-by-Light Aircraft Closed-Loop Test (FACT) program is a flight test program sponsored by NASA-Lewis Research Center. The objectives of the FACT program are to demonstrate optical closed-loop control of flight critical and non-flight critical control surfaces and to demonstrate installation and maintenance aspects of fiber optics for application to commercial aircraft. This paper summarizes the FACT program optical maintenance, test architecture, and hardware developments to be flight tested on the NASA-Dryden F/A-18 Systems Research Aircraft (SRA). The modifications include replacing Fly-By-Wire (FBW) main ram feedback LVDT's with optic position sensors and an electro-optic decoder, and using electrical to optic converters and reverse for commands. The performance and handling qualities will be validated by laboratory, ground, and flight tests. The goal is to demonstrate system performance equivalent to the production system.

  1. Composite Structure Modeling and Analysis of Advanced Aircraft Fuselage Concepts

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivek; Sorokach, Michael R.

    2015-01-01

    NASA Environmentally Responsible Aviation (ERA) project and the Boeing Company are collabrating to advance the unitized damage arresting composite airframe technology with application to the Hybrid-Wing-Body (HWB) aircraft. The testing of a HWB fuselage section with Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) construction is presently being conducted at NASA Langley. Based on lessons learned from previous HWB structural design studies, improved finite-element models (FEM) of the HWB multi-bay and bulkhead assembly are developed to evaluate the performance of the PRSEUS construction. In order to assess the comparative weight reduction benefits of the PRSEUS technology, conventional cylindrical skin-stringer-frame models of a cylindrical and a double-bubble section fuselage concepts are developed. Stress analysis with design cabin-pressure load and scenario based case studies are conducted for design improvement in each case. Alternate analysis with stitched composite hat-stringers and C-frames are also presented, in addition to the foam-core sandwich frame and pultruded rod-stringer construction. The FEM structural stress, strain and weights are computed and compared for relative weight/strength benefit assessment. The structural analysis and specific weight comparison of these stitched composite advanced aircraft fuselage concepts demonstrated that the pressurized HWB fuselage section assembly can be structurally as efficient as the conventional cylindrical fuselage section with composite stringer-frame and PRSEUS construction, and significantly better than the conventional aluminum construction and the double-bubble section concept.

  2. Large Field Photogrammetry Techniques in Aircraft and Spacecraft Impact Testing

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2010-01-01

    The Landing and Impact Research Facility (LandIR) at NASA Langley Research Center is a 240 ft. high A-frame structure which is used for full-scale crash testing of aircraft and rotorcraft vehicles. Because the LandIR provides a unique capability to introduce impact velocities in the forward and vertical directions, it is also serving as the facility for landing tests on full-scale and sub-scale Orion spacecraft mass simulators. Recently, a three-dimensional photogrammetry system was acquired to assist with the gathering of vehicle flight data before, throughout and after the impact. This data provides the basis for the post-test analysis and data reduction. Experimental setups for pendulum swing tests on vehicles having both forward and vertical velocities can extend to 50 x 50 x 50 foot cubes, while weather, vehicle geometry, and other constraints make each experimental setup unique to each test. This paper will discuss the specific calibration techniques for large fields of views, camera and lens selection, data processing, as well as best practice techniques learned from using the large field of view photogrammetry on a multitude of crash and landing test scenarios unique to the LandIR.

  3. 76 FR 45011 - Control of Air Pollution From Aircraft and Aircraft Engines; Proposed Emission Standards and Test...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-27

    ... comment includes information claimed to be Confidential Business Information (CBI) or other information... Procedures for Aircraft;'' Final Rule, 38 FR 19088, July 17, 1973. \\12\\ U.S. EPA, ``Control of Air Pollution from Aircraft and Aircraft Engines; Emission Standards and Test Procedures;'' Final Rule, 62 FR...

  4. Engine-induced structural-borne noise in a general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.; Scheidt, D. C.; Pomerening, D. J.

    1979-01-01

    Structural borne interior noise in a single engine general aviation aircraft was studied to determine the importance of engine induced structural borne noise and to determine the necessary modeling requirements for the prediction of structural borne interior noise. Engine attached/detached ground test data show that engine induced structural borne noise is a primary interior noise source for the single engine test aircraft, cabin noise is highly influenced by responses at the propeller tone, and cabin acoustic resonances can influence overall noise levels. Results from structural and acoustic finite element coupled models of the test aircraft show that wall flexibility has a strong influence on fundamental cabin acoustic resonances, the lightweight fuselage structure has a high modal density, and finite element analysis procedures are appropriate for the prediction of structural borne noise.

  5. Effects of aircraft noise on flight and ground structures

    NASA Technical Reports Server (NTRS)

    Mixson, J. S.; Mayes, W. H.; Willis, C. M.

    1976-01-01

    Acoustic loads measured on jet-powered STOL configurations are presented for externally blown and upper surface blown flap models ranging in size from a small laboratory model up to a full-scale aircraft model. The implications of the measured loads for potential acoustic fatigue and cabin noise are discussed. Noise transmission characteristics of light aircraft structures are presented. The relative importance of noise transmission paths, such as fuselage sidewall and primary structure, is estimated. Acceleration responses of a historic building and a residential home are presented for flyover noise from subsonic and supersonic aircraft. Possible effects on occupant comfort are assessed. The results from these three examples show that aircraft noise can induce structural responses that are large enough to require consideration in the design or operation of the aircraft.

  6. Resin transfer molding for advanced composite primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Markus, Alan; Palmer, Ray

    1991-01-01

    Resin Transfer Molding (RTM) has been identified by Douglas Aircraft Company (DAC) and industry to be one of the promising processes being developed today which can break the cost barrier of implementing composite primary structures into a commercial aircraft production environment. The RTM process developments and scale-up plans Douglas Aircrart will be conducting under the NASA ACT contract are discussed.

  7. A flight test method for pilot/aircraft analysis

    NASA Technical Reports Server (NTRS)

    Koehler, R.; Buchacker, E.

    1986-01-01

    In high precision flight maneuvres a pilot is a part of a closed loop pilot/aircraft system. The assessment of the flying qualities is highly dependent on the closed loop characteristics related to precision maneuvres like approach, landing, air-to-air tracking, air-to-ground tracking, close formation flying and air-to air refueling of the receiver. The object of a research program at DFVLR is the final flight phase of an air to ground mission. In this flight phase the pilot has to align the aircraft with the target, correct small deviations from the target direction and keep the target in his sights for a specific time period. To investigate the dynamic behavior of the pilot-aircraft system a special ground attack flight test technique with a prolonged tracking maneuvres was developed. By changing the targets during the attack the pilot is forced to react continously on aiming errors in his sights. Thus the closed loop pilot/aircraft system is excited over a wide frequency range of interest, the pilot gets more information about mission oriented aircraft dynamics and suitable flight test data for a pilot/aircraft analysis can be generated.

  8. Application of fiber Bragg grating sensors in light aircraft: ground and flight test

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyuk; Shrestha, Pratik; Park, Yurim; Kim, Chun-Gon

    2014-05-01

    Fiber optic sensors are being spotlighted as the means to monitoring aircraft conditions due to their excellent characteristics. This paper presents an affordable structural health monitoring system based on a fiber Bragg grating sensor (FBG) for application in light aircrafts. A total of 24 FBG sensors were installed in the main wing of the test bed aircraft. In the ground test, the intactness of the installed sensors and device operability were confirmed. During the flight test, the strain and temperature responses of the wing structure were measured by the on-board low-speed FBG interrogator. The measured strains were successfully converted into the flight load history through the load calibration coefficient obtained from the ground calibration test.

  9. Simulation of Aircraft Engine Blade-Out Structural Dynamics. Revised

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Carney, Kelly; Gallardo, Vicente

    2001-01-01

    A primary concern of aircraft structure designers is the accurate simulation of the blade-out event and the subsequent windmilling of the engine. Reliable simulations of the blade-out event are required to insure structural integrity during flight as well as to guarantee successful blade-out certification testing. The system simulation includes the lost blade loadings and the interactions between the rotating turbomachinery and the remaining aircraft structural components. General-purpose finite element structural analysis codes such as MSC NASTRAN are typically used and special provisions are made to include transient effects from the blade loss and rotational effects resulting from the engine's turbomachinery. The present study provides the equations of motion for rotordynamic response including the effect of spooldown speed and rotor unbalance and examines the effects of these terms on a cantilevered rotor. The effect of spooldown speed is found to be greater with increasing spooldown rate. The parametric term resulting from the mass unbalance has a more significant effect on the rotordynamic response than does the spooldown term. The parametric term affects both the peak amplitudes as well as the resonant frequencies of the rotor.

  10. Simulation of Aircraft Engine Blade-Out Structural Dynamics

    NASA Technical Reports Server (NTRS)

    Lawrence, Charles; Carney, Kelly; Gallardo, Vicente

    2001-01-01

    A primary concern of aircraft structure designers is the accurate simulation of the blade-out event and the subsequent windmilling of the engine. Reliable simulations of the blade-out event are required to insure structural integrity during flight as well as to guarantee successful blade-out certification testing. The system simulation includes the lost blade loadings and the interactions between the rotating turbomachinery and the remaining aircraft structural components. General-purpose finite element structural analysis codes such as MSC NASTRAN are typically used and special provisions are made to include transient effects from the blade loss and rotational effects resulting from the engine's turbomachinery. The present study provides the equations of motion for rotordynamic response including the effect of spooldown speed and rotor unbalance and examines the effects of these terms on a cantilevered rotor. The effect of spooldown speed is found to be greater with increasing spooldown rate. The parametric term resulting from the mass unbalance has a more significant effect on the rotordynamic response than does the spooldown term. The parametric term affects both the peak amplitudes as well as the resonant frequencies of the rotor.

  11. Program for establishing long-time flight service performance of composite materials in the center wing structure of C-130 aircraft. Phase 4: Ground/flight acceptance tests

    NASA Technical Reports Server (NTRS)

    Harvill, W. E.; Kizer, J. A.

    1976-01-01

    The advantageous structural uses of advanced filamentary composites are demonstrated by design, fabrication, and test of three boron-epoxy reinforced C-130 center wing boxes. The advanced development work necessary to support detailed design of a composite reinforced C-130 center wing box was conducted. Activities included the development of a basis for structural design, selection and verification of materials and processes, manufacturing and tooling development, and fabrication and test of full-scale portions of the center wing box. Detailed design drawings, and necessary analytical structural substantiation including static strength, fatigue endurance, flutter, and weight analyses are considered. Some additional component testing was conducted to verify the design for panel buckling, and to evaluate specific local design areas. Development of the cool tool restraint concept was completed, and bonding capabilities were evaluated using full-length skin panel and stringer specimens.

  12. Flight Testing the Rotor Systems Research Aircraft (RSRA)

    NASA Technical Reports Server (NTRS)

    Hall, G. W.; Merrill, R. K.

    1983-01-01

    In the late 1960s, efforts to advance the state-of-the-art in rotor systems technology indicated a significant gap existed between our ability to accurately predict the characteristics of a complex rotor system and the results obtained through flight verification. Even full scale wind tunnel efforts proved inaccurate because of the complex nature of a rotating, maneuvering rotor system. The key element missing, which prevented significant advances, was our inability to precisely measure the exact rotor state as a function of time and flight condition. Two Rotor Research Aircraft (RSRA) were designed as pure research aircraft and dedicated rotor test vehicles whose function is to fill the gap between theory, wind tunnel testing, and flight verification. The two aircraft, the development of the piloting techniques required to safely fly the compound helicopter, the government flight testing accomplished to date, and proposed future research programs.

  13. Crack Turning in Integrally Stiffened Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Pettit, Richard Glen

    2000-01-01

    Current emphasis in the aircraft industry toward reducing manufacturing cost has created a renewed interest in integrally stiffened structures. Crack turning has been identified as an approach to improve the damage tolerance and fail-safety of this class of structures. A desired behavior is for skin cracks to turn before reaching a stiffener, instead of growing straight through. A crack in a pressurized fuselage encounters high T-stress as it nears the stiffener--a condition favorable to crack turning. Also, the tear resistance of aluminum alloys typically varies with crack orientation, a form of anisotropy that can influence the crack path. The present work addresses these issues with a study of crack turning in two-dimensions, including the effects of both T-stress and fracture anisotropy. Both effects are shown to have relation to the process zone size, an interaction that is central to this study. Following an introduction to the problem, the T-stress effect is studied for a slightly curved semi-infinite crack with a cohesive process zone, yielding a closed form expression for the future crack path in an infinite medium. For a given initial crack tip curvature and tensile T-stress, the crack path instability is found to increase with process zone size. Fracture orthotropy is treated using a simple function to interpolate between the two principal fracture resistance values in two-dimensions. An extension to three-dimensions interpolates between the six principal values of fracture resistance. Also discussed is the transition between mode I and mode II fracture in metals. For isotropic materials, there is evidence that the crack seeks out a direction of either local symmetry (pure mode I) or local asymmetry (pure mode II) growth. For orthotropic materials the favored states are not pure modal, and have mode mixity that is a function of crack orientation.

  14. Performance analysis of bonded composite doublers on aircraft structures

    SciTech Connect

    Roach, D.

    1995-08-01

    Researchers contend that composite repairs (or structural reinforcement doublers) offer numerous advantages over metallic patches including corrosion resistance, light weight, high strength, elimination of rivets, and time savings in installation. Their use in commercial aviation has been stifled by uncertainties surrounding their application, subsequent inspection and long-term endurance. The process of repairing or reinforcing airplane structures is time consuming and the design is dependent upon an accompanying stress and fatigue analysis. A repair that is too stiff may result in a loss of fatigue life, continued growth of the crack being repaired, and the initiation of a new flaw in the undesirable high stress field around the patch. Uncertainties in load spectrums used to design repairs exacerbates these problems as does the use of rivets to apply conventional doublers. Many of these repair or structural reinforcement difficulties can be addressed through the use of composite doublers. Primary among unknown entities are the effects of non-optimum installations and the certification of adequate inspection procedures. This paper presents on overview of a program intended to introduce composite doubler technology to the US commercial aircraft fleet. In this project, a specific composite application has been chosen on an L-1011 aircraft in order to focus the tasks on application and operation issues. Through the use of laboratory test structures and flight demonstrations on an in-service L-1011 airplane, this study is investigating composite doubler design, fabrication, installation, structural integrity, and non-destructive evaluation. In addition to providing an overview of the L-1011 project, this paper focuses on a series of fatigue and strength tests which have been conducted in order to study the damage tolerance of composite doublers. Test results to-date are presented.

  15. Flight Test Safety Considerations for Airborne Science Aircraft

    NASA Technical Reports Server (NTRS)

    Reynolds, Randolph S.

    1997-01-01

    Most of the scientific community that require scientific data or scientific measurements from aircraft do not understand the full implications of putting certain equipment on board high performance aircraft. It is the duty of the NASA Flight Operations personnel to ensure that all Principal Investigators who are given space on NASA flight research aircraft, comply with stringent safety requirements. The attitude of the experienced Flight operations personnel given this duty has been and remains one of insuring that the PI's experiment is allowed to be placed on the aircraft (facility) and can be operated in a manner that will obtain the expected data. This is sometimes a challenge. The success that NASA has in this regard is due to the fact that it is its own authority under public law, to certify its aircraft as airworthy. Airworthiness, fitness for flight, is a complex issue which pulls together all aspects of configuration management, engineering, quality, and flight safety. It is often the case at each NASA Center that is conducting airborne research, that unique solutions to some challenging safety issues are required. These solutions permit NASA to do things that would not be permitted by the Department of Transportation. This paper will use examples of various flight research configurations to show the necessity of a disciplined process leading up to flight test and mission implementation. All new configurations required engineering flight test but many, as noted in this paper, require that the modifications be flight tested to insure that they do not negatively impact on any part of the aircraft operational profiles. The success of these processes has been demonstrated over many years and NASA has accommodated experimental packages that cannot be flown on any other aircraft.

  16. Structural risk assessment and aircraft fleet maintenance

    NASA Technical Reports Server (NTRS)

    Smith, Herb, Jr.; Saff, C. R.; Christian, Tom F.

    1990-01-01

    In the present analysis, deterministic flaw growth analysis is used to project the failure distributions from inspection data. Inspection data is reported for each critical point in the aircraft. The data will indicate either a crack of a specific size or no crack. The crack length may be either less than, equal to, or greater than critical size for that location. Non-critical length cracks are projected to failure using the crack growth characteristics for that location to find the life when it will be at critical length. Greater-than-critical length cracks are projected back to determine the life at failure, that is, when it was at critical length. The same process is used as in the case of a non-critical crack except that the projection goes the other direction. These points, along with the critical length cracks are used to determine the failure distribution. To be able to use data from different aircraft to build a common failure distribution, a consistent life variable must be used. Aircraft life varies with the severity of the usage; therefore the number of flight hours for a particular aircraft must be modified by its usage factor to obtain a normalized life which can be compared with that from other aircraft.

  17. Variable Geometry Aircraft Pylon Structure and Related Operation Techniques

    NASA Technical Reports Server (NTRS)

    Shah, Parthiv N. (Inventor)

    2014-01-01

    An aircraft control structure can be utilized for purposes of drag management, noise control, or aircraft flight maneuvering. The control structure includes a high pressure engine nozzle, such as a bypass nozzle or a core nozzle of a turbofan engine. The nozzle exhausts a high pressure fluid stream, which can be swirled using a deployable swirl vane architecture. The control structure also includes a variable geometry pylon configured to be coupled between the nozzle and the aircraft. The variable geometry pylon has a moveable pylon section that can be deployed into a deflected state to maintain or alter a swirling fluid stream (when the swirl vane architecture is deployed) for drag management purposes, or to assist in the performance of aircraft flight maneuvers.

  18. Ames T-3 fire test facility - Aircraft crash fire simulation

    NASA Technical Reports Server (NTRS)

    Fish, R. H.

    1976-01-01

    There is a need to characterize the thermal response of materials exposed to aircraft fuel fires. Large scale open fire tests are costly and pollute the local environment. This paper describes the construction and operation of a subscale fire test that simulates the heat flux levels and thermochemistry of typical open pool fires. It has been termed the Ames T-3 Test and has been used extensively by NASA since 1969 to observe the behavior of materials exposed to JP-4 fuel fires.

  19. 14 CFR 121.163 - Aircraft proving tests.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Aircraft proving tests. 121.163 Section 121.163 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS...

  20. 78 FR 68360 - Unmanned Aircraft System Test Site Program

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-14

    ... comments published in the Federal Register on February 22, 2013 (78 FR 12259), Docket No. FAA-2013-0061... (78 FR 18932), Docket No. FAA-2013-0061- 0050. In addition, this document publishes the FAA's Final... Federal Aviation Administration 14 CFR Part 91 Unmanned Aircraft System Test Site Program AGENCY:...

  1. 14 CFR 21.128 - Tests: aircraft engines.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... engines. (a) Each person manufacturing aircraft engines under a type certificate must subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to an acceptable...) The test runs required by paragraph (a) of this section may be made with the engine...

  2. 14 CFR 21.128 - Tests: aircraft engines.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... engines. (a) Each person manufacturing aircraft engines under a type certificate must subject each engine (except rocket engines for which the manufacturer must establish a sampling technique) to an acceptable...) The test runs required by paragraph (a) of this section may be made with the engine...

  3. Structural dynamics and vibrations of damped, aircraft-type structures

    NASA Technical Reports Server (NTRS)

    Young, Maurice I.

    1992-01-01

    Engineering preliminary design methods for approximating and predicting the effects of viscous or equivalent viscous-type damping treatments on the free and forced vibration of lightly damped aircraft-type structures are developed. Similar developments are presented for dynamic hysteresis viscoelastic-type damping treatments. It is shown by both engineering analysis and numerical illustrations that the intermodal coupling of the undamped modes arising from the introduction of damping may be neglected in applying these preliminary design methods, except when dissimilar modes of these lightly damped, complex aircraft-type structures have identical or nearly identical natural frequencies. In such cases, it is shown that a relatively simple, additional interaction calculation between pairs of modes exhibiting this 'modal response' phenomenon suffices in the prediction of interacting modal damping fractions. The accuracy of the methods is shown to be very good to excellent, depending on the normal natural frequency separation of the system modes, thereby permitting a relatively simple preliminary design approach. This approach is shown to be a natural precursor to elaborate finite element, digital computer design computations in evaluating the type, quantity, and location of damping treatment.

  4. Column and Plate Compressive Strengths of Aircraft Structural Martials Extruded 0-1HTA Magnesium Alloy

    NASA Technical Reports Server (NTRS)

    Heimerl, George J; Niles, Donald E

    1947-01-01

    Column and plate compressive strengths of extruded 0-1HTA magnesium alloy were determined both within and beyond the elastic range from tests of flat end H-section columns and from local instability tests of H-, Z-, and channel section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.

  5. Column and Plate Compressive Strengths of Aircraft Structural Materials: Extruded 24S-T Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Heimerl, George J.; Roy, J Albert

    1945-01-01

    Column and plate compressive strengths of extruded 24S-T aluminum alloy were determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-,and channel-section columns. These tests are part of an extensive research investigation to provide data on the' structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures.

  6. Advanced organic composite materials for aircraft structures: Future program

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Revolutionary advances in structural materials have been responsible for revolutionary changes in all fields of engineering. These advances have had and are still having a significant impact on aircraft design and performance. Composites are engineered materials. Their properties are tailored through the use of a mix or blend of different constituents to maximize selected properties of strength and/or stiffness at reduced weights. More than 20 years have passed since the potentials of filamentary composite materials were identified. During the 1970s much lower cost carbon filaments became a reality and gradually designers turned from boron to carbon composites. Despite progress in this field, filamentary composites still have significant unfulfilled potential for increasing aircraft productivity; the rendering of advanced organic composite materials into production aircraft structures was disappointingly slow. Why this is and research and technology development actions that will assist in accelerating the application of advanced organic composites to production aircraft is discussed.

  7. Experimental Photogrammetric Techniques Used on Five Full-Scale Aircraft Crash Tests

    NASA Technical Reports Server (NTRS)

    Littell, Justin D.

    2016-01-01

    Between 2013 and 2015, full-scale crash tests were conducted on five aircraft at the Landing and Impact Research Facility (LandIR) at NASA Langley Research Center (LaRC). Two tests were conducted on CH-46E airframes as part of the Transport Rotorcraft Airframe Crash Testbed (TRACT) project, and three tests were conduced on Cessna 172 aircraft as part of the Emergency Locator Transmitter Survivability and Reliability (ELTSAR) project. Each test served to evaluate a variety of crashworthy systems including: seats, occupants, restraints, composite energy absorbing structures, and Emergency Locator Transmitters. As part of each test, the aircraft were outfitted with a variety of internal and external cameras that were focused on unique aspects of the crash event. A subset of three camera was solely used in the acquisition of photogrammetric test data. Examples of this data range from simple two-dimensional marker tracking for the determination of aircraft impact conditions to entire full-scale airframe deformation to markerless tracking of Anthropomorphic Test Devices (ATDs, a.k.a. crash test dummies) during the crash event. This report describes and discusses the techniques used and implications resulting from the photogrammetric data acquired from each of the five tests.

  8. Composite structural materials. [fiber reinforced composites for aircraft structures

    NASA Technical Reports Server (NTRS)

    Ansell, G. S.; Loewy, R. G.; Wiberly, S. E.

    1981-01-01

    Physical properties of fiber reinforced composites; structural concepts and analysis; manufacturing; reliability; and life prediction are subjects of research conducted to determine the long term integrity of composite aircraft structures under conditions pertinent to service use. Progress is reported in (1) characterizing homogeneity in composite materials; (2) developing methods for analyzing composite materials; (3) studying fatigue in composite materials; (4) determining the temperature and moisture effects on the mechanical properties of laminates; (5) numerically analyzing moisture effects; (6) numerically analyzing the micromechanics of composite fracture; (7) constructing the 727 elevator attachment rib; (8) developing the L-1011 engine drag strut (CAPCOMP 2 program); (9) analyzing mechanical joints in composites; (10) developing computer software; and (11) processing science and technology, with emphasis on the sailplane project.

  9. Aircraft seat cushion materials tests. [flammability

    NASA Technical Reports Server (NTRS)

    Bricker, R. W.

    1975-01-01

    Five component level flammability tests were conducted in a 400 cubic foot chamber to determine the products of combustion and relative destruction of coated (with fire-retardants) and uncoated polyurethane foams during exposure of the foams to a large flaming ignition source for five minutes. The test results indicate that the improved state-of-the-art polyurethane foams without the added fire retardant and coating treatments were not significantly better than untreated older less fire-resistant polyurethane foams. however, by treating and coating the state-of-the-art foams, the production of toxic gases was delayed and the destruction of the foam limited.

  10. Flight testing the Rotor Systems Research Aircraft (RSRA)

    NASA Technical Reports Server (NTRS)

    Merrill, R. K.; Hall, G. W.

    1982-01-01

    The Rotor Systems Research Aircraft (RSRA) is a dedicated rotor test vehicle whose function is to fill the gap between theory, wind tunnel tests and flight verification data. Its flight test envelope has been designed to encompass the expected envelopes of future rotor systems under all flight conditions. The test configurations of the RSRA include pure helicopter and compound (winged helicopter) modes. In addition, should it become necessary to jettison an unstable rotor system in flight, the RSRA may be flown as a fixed wing aircraft. The heart of the RSRA's electronic flight control system is the TDY-43 computer, which can be programmed in numerous ways to change stability and control or force feel system gains. Computer programming changes allow the RSRA to be used as a five-degree-of-freedom inflight simulator for studying the handling qualities of research rotors.

  11. Electron beam welding of aircraft structures. [joining of titanium alloy wing structures on F-14 aircraft

    NASA Technical Reports Server (NTRS)

    Witt, R. H.

    1972-01-01

    Requirements for advanced aircraft have led to more extensive use of titanium alloys and the resultant search for joining processes which can produce lightweight, high strength airframe structures efficiently. As a result, electron beam welding has been investigated. The following F-14A components are now being EB welded in production and are mainly annealed Ti-6Al-4V except for the upper wing cover which is annealed Ti-6Al-6V-2Sn: F-14A wing center section box, and F-14A lower and upper wing covers joined to wing pivot fitting assemblies. Criteria for selection of welding processes, the EB welding facility, development work on EB welding titanium alloys, and F-14A production and sliding seal electron beam welding are reported.

  12. Integrated Control with Structural Feedback to Enable Lightweight Aircraft

    NASA Technical Reports Server (NTRS)

    Taylor, Brian R.

    2011-01-01

    This presentation for the Fundamental Aeronautics Program Technical Conference covers the benefits of active structural control, related research areas, and focuses on the use of optimal control allocation for the prevention of critical loads. Active control of lightweight structures has the potential to reduce aircraft weight and fuel burn. Sensor, control law, materials, control effector, and system level research will be necessary to enable active control of lightweight structures. Optimal control allocation with structural feedback has been shown in simulation to be feasible in preventing critical loads and is one example of a control law to enable future lightweight aircraft.

  13. Measurement and analysis of aircraft and vehicle LRCS in outfield test

    NASA Astrophysics Data System (ADS)

    Cao, Chang-Qing; Zeng, Xiao-dong; Fan, Zhao-jin; Feng, Zhe-jun; Lai, Zhi

    2015-04-01

    The measurement of aircraft and vehicle Laser Radar Cross Section (LRCS) is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering. A brief introduction of the measuring theory of the laser scattering from the full-scale aircraft and vehicle targets is presented in this paper. By analyzing the measuring condition in outfield test, the laser systems and test steps are designed for full-scale aircraft and vehicle LRCS and verified by the experiment in laboratory. The processing data error 7% below is obtained of the laser radar cross section by using Gaussian compensation and elimination of sky background for original test data. The study of measurement and analysis proves that the proposed method is effective and correct to get laser radar cross section data in outfield test. The objectives of this study were: (1) to develop structural concepts for different LRCS fuselage configurations constructed of conventional materials; (2) to compare these findings with those of aircrafts or vehicles; (3) to assess the application of advanced materials for each configuration; (4) to conduct an analytical investigation of the aerodynamic loads, vertical drag and mission performance of different LRCS configurations; and (5) to compare these findings with those of the aircrafts or vehicles.

  14. Structural Integrity Evaluation of the Lear Fan 2100 Aircraft

    NASA Technical Reports Server (NTRS)

    Kan, H. P.; Dyer, T. A.

    1996-01-01

    An in-situ nondestructive inspection was conducted to detect manufacturing and assembly induced defects in the upper two wing surfaces (skin s) and upper fuselage skin of the Lear Fan 2100 aircraft E009. The effects of the defects, detected during the inspection, on the integrity of the structure was analytically evaluated. A systematic evaluation was also conducted to determine the damage tolerance capability of the upper wing skin against impact threats and assembly induced damage. The upper wing skin was divided into small regions for damage tolerance evaluations. Structural reliability, margin of safety, allowable strains, and allowable damage size were computed. The results indicated that the impact damage threat imposed on composite military aircraft structures is too severe for the Lear Fan 2100 upper wing skin. However, the structural integrity is not significantly degraded by the assembly induced damage for properly assembled structures, such as the E009 aircraft.

  15. Distortion of conformal antennas on aircraft structures

    NASA Astrophysics Data System (ADS)

    Schippers, Harmen; van Tongeren, Hans; Verpoorte, Jaco; Vos, Guus

    2001-08-01

    Conformal antennas on aircraft allow the use of non-conventional antenna locations such as the skin of the aircraft. However, when antennas are installed at these locations they are subject to steady and unsteady aerodynamic loads. The inertial forces and these aerodynamic loads will cause deformations and vibrations of the total antenna surface. The effect of these distortions on antenna performance will be most significant on highly directional antennas. The aim of the present paper is to describe technology development for estimating the effects of surface distortion on antenna performance. The technology is applied to a Side-Looking Airborne Radar (SLAR) antenna on a reconnaissance pod mounted on a fighter type aircraft. This generic SLAR antenna is a phased array antenna covering two faces of the pod: one part on the vertical side face and one part on the lower face of the pod. Radiation patterns are computed for distorted antenna surfaces. The computational model for the determination of the disturbed radiation pattern is based on geometrical parameterisation of the Stratton-Chu integral equations.

  16. Aircraft Cargo Compartment Fire Test Simulation Program

    NASA Technical Reports Server (NTRS)

    Blumke, R. E.

    1977-01-01

    The objective of the test was to assess fire containment and fire extinguishment in the cargo by reducing the ventilation through the cargo compartment. Parameters which were measured included ignition time, burnthrough time, and physical damage to the cargo liner, composition of selected combustible gases, temperature-time histories, heat flux, and detector response. The ignitor load was made of a typical cargo consisting of filled cardboard cartons occupying 50% of the compartment volume.

  17. Wireless microsensors for health monitoring of aircraft structures

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.

    2003-01-01

    The integration of MEMS, IDTs (interdigital transducers) and required microelectronics and conformal antennas to realize programmable, robust and low cost passive microsensors suitable for many military structures and systems including aircraft, missiles and munitions is presented in this paper. The technology is currently being applied to the structural health monitoring of critical aircraft components. The approach integrates acoustic emission, strain gauges, MEMS accelerometers, gyroscopes and vibration monitoring devices with signal processing electronics to provide real-time indicators of incipient failure of aircraft components with a known history of catastrophic failure due to fracture. Recently a combination of the need for safety in the air and the desire to control costs is encouraging the use of in-flight monitoring of aircraft components and systems using light-weight, wireless and cost effective microsensors and MEMS. An in-situ Aircraft structural health monitoring (ASHM) system, with sensors embedded in the composite structure or surface-mounted on the structure, would permit the timely detection of damage in aircraft. Micromachining offers the potential for fabricating a range of microsensors and MEMS for structural applications including load, vibration and acoustics characterization and monitoring. Such microsensors are extremely small; they can be embedded into structural materials, can be mass-produced and are therefore potentially cheap. Additionally a range of sensor types can be integrated onto a single chip with built-in electronics and ASIC (Application Specific Integrated Circuit), providing a low power Microsystems. The smart sensors are being developed using the standard microelectronics and micromachining in conjunction with novel Penn State smart electronics or wireless communication systems suitable for condition monitoring of aircraft structures in-flight. A hybrid accelerometer and gyroscope in a single chip suitable for inertial

  18. Titanium honeycomb structure. [for supersonic aircraft wing structure

    NASA Technical Reports Server (NTRS)

    Davis, R. A.; Elrod, S. D.; Lovell, D. T.

    1972-01-01

    A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.

  19. Flight testing a highly flexible aircraft - Case study on the MIT Light Eagle

    NASA Technical Reports Server (NTRS)

    Zerweckh, S. H.; Von Flotow, A. H.; Murray, J. E.

    1988-01-01

    This paper describes the techniques developed for a flight test program of a human powered aircraft, the application of these techniques in the winter of 1987/88 and the results of the flight testing. A system of sensors, signal conditioning and data recording equipment was developed and installed in the aircraft. Flight test maneuvers which do not exceed the aircraft's limited capability were developed and refined in an iterative sequence of test flights. The test procedures were adjusted to yield maximum data quality from the point of view of estimating lateral and longitudinal stability derivatives. Structural flexibility and unsteady aerodynamics are modeled in an ad hoc manner, capturing the effects observed during the test flights. A model with flexibility-extended equations of motion is presented. Results of maneuvers that were flown are compared with the predictions of that model and analyzed. Finally the results of the flight test program are examined critically, especially with respect to future applications, and suggestions are made in order to improve maneuvers for parameter estimation of very flexible aircraft.

  20. LFC leading edge glove flight: Aircraft modification design, test article development and systems integration

    NASA Technical Reports Server (NTRS)

    Etchberger, F. R.

    1983-01-01

    Reduction of skin friction drag by suction of boundary layer air to maintain laminar flow has been known since Prandtl's published work in 1904. The dramatic increases in fuel costs and the potential for periods of limited fuel availability provided the impetus to explore technologies to reduce transport aircraft fuel consumption. NASA sponsored the Aircraft Energy Efficiency (ACEE) program in 1976 to develop technologies to improve fuel efficiency. This report documents the Lockheed-Georgia Company accomplishments in designing and fabricating a leading-edge flight test article incorporating boundary layer suction slots to be flown by NASA on their modified JetStar aircraft. Lockheed-Georgia Company performed as the integration contractor to design the JetStar aircraft modification to accept both a Lockheed and a McDonnell Douglas flight test article. McDonnell Douglas uses a porous skin concept. The report describes aerodynamic analyses, fabrication techniques, JetStar modifications, instrumentation requirements, and structural analyses and testing for the Lockheed test article. NASA will flight test the two LFC leading-edge test articles in a simulated commercial environment over a 6 to 8 month period in 1984. The objective of the flight test program is to evaluate the effectiveness of LFC leading-edge systems in reducing skin friction drag and consequently improving fuel efficiency.

  1. Development of pressure containment and damage tolerance technology for composite fuselage structures in large transport aircraft

    NASA Technical Reports Server (NTRS)

    Smith, P. J.; Thomson, L. W.; Wilson, R. D.

    1986-01-01

    NASA sponsored composites research and development programs were set in place to develop the critical engineering technologies in large transport aircraft structures. This NASA-Boeing program focused on the critical issues of damage tolerance and pressure containment generic to the fuselage structure of large pressurized aircraft. Skin-stringer and honeycomb sandwich composite fuselage shell designs were evaluated to resolve these issues. Analyses were developed to model the structural response of the fuselage shell designs, and a development test program evaluated the selected design configurations to appropriate load conditions.

  2. Development of thermoplastic composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Renieri, Michael P.; Burpo, Steven J.; Roundy, Lance M.; Todd, Stephanie A.; Kim, H. J.

    1992-01-01

    Efforts focused on the use of thermoplastic composite materials in the development of structural details associated with an advanced fighter fuselage section with applicability to transport design. In support of these designs, mechanics developments were conducted in two areas. First, a dissipative strain energy approach to material characterization and failure prediction, developed at the Naval Research Laboratory, was evaluated as a design/analysis tool. Second, a finite element formulation for thick composites was developed and incorporated into a lug analysis method which incorporates pin bending effects. Manufacturing concepts were developed for an upper fuel cell cover. A detailed trade study produced two promising concepts: fiber placement and single-step diaphragm forming. Based on the innovative design/manufacturing concepts for the fuselage section primary structure, elements were designed, fabricated, and structurally tested. These elements focused on key issues such as thick composite lugs and low cost forming of fastenerless, stiffener/moldine concepts. Manufacturing techniques included autoclave consolidation, single diaphragm consolidation (SDCC) and roll-forming.

  3. Advances in Fatigue and Fracture Mechanics Analyses for Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.

    1999-01-01

    This paper reviews some of the advances that have been made in stress analyses of cracked aircraft components, in the understanding of the fatigue and fatigue-crack growth process, and in the prediction of residual strength of complex aircraft structures with widespread fatigue damage. Finite-element analyses of cracked structures are now used to determine accurate stress-intensity factors for cracks at structural details. Observations of small-crack behavior at open and rivet-loaded holes and the development of small-crack theory has lead to the prediction of stress-life behavior for components with stress concentrations under aircraft spectrum loading. Fatigue-crack growth under simulated aircraft spectra can now be predicted with the crack-closure concept. Residual strength of cracked panels with severe out-of-plane deformations (buckling) in the presence of stiffeners and multiple-site damage can be predicted with advanced elastic-plastic finite-element analyses and the critical crack-tip-opening angle (CTOA) fracture criterion. These advances are helping to assure continued safety of aircraft structures.

  4. 77 FR 65823 - Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-31

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 87 RIN 2060-AO70 Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures Correction In rule document 2012-13828 appearing on pages...

  5. Advanced methods of structural and trajectory analysis for transport aircraft

    NASA Technical Reports Server (NTRS)

    Ardema, Mark D.

    1995-01-01

    This report summarizes the efforts in two areas: (1) development of advanced methods of structural weight estimation, and (2) development of advanced methods of trajectory optimization. The majority of the effort was spent in the structural weight area. A draft of 'Analytical Fuselage and Wing Weight Estimation of Transport Aircraft', resulting from this research, is included as an appendix.

  6. Fabrication and evaluation of advanced titanium structural panels for supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Payne, L.

    1977-01-01

    Flightworthy primary structural panels were designed, fabricated, and tested to investigate two advanced fabrication methods for titanium alloys. Skin-stringer panels fabricated using the weldbraze process, and honeycomb-core sandwich panels fabricated using a diffusion bonding process, were designed to replace an existing integrally stiffened shear panel on the upper wing surface of the NASA YF-12 research aircraft. The investigation included ground testing and Mach 3 flight testing of full-scale panels, and laboratory testing of representative structural element specimens. Test results obtained on full-scale panels and structural element specimens indicate that both of the fabrication methods investigated are suitable for primary structural applications on future civil and military supersonic cruise aircraft.

  7. The SR-71 Test Bed Aircraft: A Facility for High-Speed Flight Research

    NASA Technical Reports Server (NTRS)

    Corda, Stephen; Moes, Timothy R.; Mizukami, Masashi; Hass, Neal E.; Jones, Daniel; Monaghan, Richard C.; Ray, Ronald J.; Jarvis, Michele L.; Palumbo, Nathan

    2000-01-01

    The SR-71 test bed aircraft is shown to be a unique platform to flight-test large experiments to supersonic Mach numbers. The test bed hardware mounted on the SR-71 upper fuselage is described. This test bed hardware is composed of a fairing structure called the "canoe" and a large "reflection plane" flat plate for mounting experiments. Total experiment weights, including the canoe and reflection plane, as heavy as 14,500 lb can be mounted on the aircraft and flight-tested to speeds as fast as Mach 3.2 and altitudes as high as 80,000 ft. A brief description of the SR-71 aircraft is given, including details of the structural modifications to the fuselage, modifications to the J58 engines to provide increased thrust, and the addition of a research instrumentation system. Information is presented based on flight data that describes the SR-71 test bed aerodynamics, stability and control, structural and thermal loads, the canoe internal environment, and reflection plane flow quality. Guidelines for designing SR-71 test bed experiments are also provided.

  8. En route noise: NASA propfan test aircraft (calculated source noise

    NASA Technical Reports Server (NTRS)

    Rickley, E. J.

    1990-01-01

    The second phase of a joint National Aeronautics and Space Administration (NASA) and Federal Aviation Administration (FAA) program to study the high-altitude, low-frequency acoustic noise propagation characteristics of the Advanced Turboprop (propfan) Aircraft was conducted on April 3-13, 1989 at the White Sands Missile Range (WSMR), New Mexico. The first phase was conducted on October 26-31, 1987 in Huntsville, Alabama. NASA (Lewis) measured the source noise of the test aircraft during both phases while NASA (Langley) measured surface noise only during the second phase. FAA/NASA designed a program to obtain noise level data from the propfan test bed aircraft, both in the near field and at ground level, during simulated en route flights (35,000 and 20,000 feet ASL), and to test low frequency atmospheric absorption algorithms and prediction technology to provide insight into the necessity for regulatory measures. The curves of calculated source noise versus emission angle are based on a second order best-fit curve of the peak envelope of the adjusted ground data. Centerline and sideline derived source noise levels are shown to be in good agreement. A comparison of the Alabama chase plane source data and the calculated source noise at centerline for both the Alabama and New Mexico data shows good agreement for the 35,000 and the 20,000 feet (ASL) overflights. With the availability of the New Mexico in-flight data, further in depth comparisons will be made.

  9. A unique facility for V/STOL aircraft hover testing

    NASA Technical Reports Server (NTRS)

    Culpepper, R. G.; Murphy, R. D.

    1979-01-01

    The paper discusses the Navy's XFV-12A tethered hover testing capabilities utilizing NASA's Impact Dynamic Research Facility (IDRF) at Langley. The facility allows for both static and dynamic tethered hover test operations to be undertaken with safety. The installation which consists of the 'Z' system (tether), restraint system, static tiedowns and the control room and console, is presented in detail. Among the capabilities demonstrated were the ability to recover the aircraft anytime during a test, to rapidly and safely define control limits, and to provide a realistic environment for pilot training and proficiency in VTOL flight.

  10. Structural Acoustic Characteristics of Aircraft and Active Control of Interior Noise

    NASA Technical Reports Server (NTRS)

    Fuller, C. R.

    1998-01-01

    The reduction of aircraft cabin sound levels to acceptable values still remains a topic of much research. The use of conventional passive approaches has been extensively studied and implemented. However performance limits of these techniques have been reached. In this project, new techniques for understanding the structural acoustic behavior of aircraft fuselages and the use of this knowledge in developing advanced new control approaches are investigated. A central feature of the project is the Aircraft Fuselage Test Facility at Va Tech which is based around a full scale Cessna Citation III fuselage. The work is divided into two main parts; the first part investigates the use of an inverse technique for identifying dominant fuselage vibrations. The second part studies the development and implementation of active and active-passive techniques for controlling aircraft interior noise.

  11. Probing Aircraft Flight Test Hazard Mitigation for the Alternative Fuel Effects on Contrails & Cruise Emissions (ACCESS) Research Team

    NASA Technical Reports Server (NTRS)

    Kelly, Michael J.

    2013-01-01

    The Alternative Fuel Effects on Contrails & Cruise Emissions (ACCESS) Project Integration Manager requested in July 2012 that the NASA Engineering and Safety Center (NESC) form a team to independently assess aircraft structural failure hazards associated with the ACCESS experiment and to identify potential flight test hazard mitigations to ensure flight safety. The ACCESS Project Integration Manager subsequently requested that the assessment scope be focused predominantly on structural failure risks to the aircraft empennage raft empennage.

  12. Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyuk; Park, Yurim; Kim, Yoon-Young; Shrestha, Pratik; Kim, Chun-Gon

    2015-10-01

    This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.

  13. Design and evaluation of a wireless sensor network based aircraft strength testing system.

    PubMed

    Wu, Jian; Yuan, Shenfang; Zhou, Genyuan; Ji, Sai; Wang, Zilong; Wang, Yang

    2009-01-01

    The verification of aerospace structures, including full-scale fatigue and static test programs, is essential for structure strength design and evaluation. However, the current overall ground strength testing systems employ a large number of wires for communication among sensors and data acquisition facilities. The centralized data processing makes test programs lack efficiency and intelligence. Wireless sensor network (WSN) technology might be expected to address the limitations of cable-based aeronautical ground testing systems. This paper presents a wireless sensor network based aircraft strength testing (AST) system design and its evaluation on a real aircraft specimen. In this paper, a miniature, high-precision, and shock-proof wireless sensor node is designed for multi-channel strain gauge signal conditioning and monitoring. A cluster-star network topology protocol and application layer interface are designed in detail. To verify the functionality of the designed wireless sensor network for strength testing capability, a multi-point WSN based AST system is developed for static testing of a real aircraft undercarriage. Based on the designed wireless sensor nodes, the wireless sensor network is deployed to gather, process, and transmit strain gauge signals and monitor results under different static test loads. This paper shows the efficiency of the wireless sensor network based AST system, compared to a conventional AST system. PMID:22408521

  14. Analytical and experimental investigation of aircraft metal structures reinforced with filamentary composites. Phase 3: Major component development

    NASA Technical Reports Server (NTRS)

    Bryson, L. L.; Mccarty, J. E.

    1973-01-01

    Analytical and experimental investigations, performed to establish the feasibility of reinforcing metal aircraft structures with advanced filamentary composites, are reported. Aluminum-boron-epoxy and titanium-boron-epoxy were used in the design and manufacture of three major structural components. The components were representative of subsonic aircraft fuselage and window belt panels and supersonic aircraft compression panels. Both unidirectional and multidirectional reinforcement concepts were employed. Blade penetration, axial compression, and inplane shear tests were conducted. Composite reinforced structural components designed to realistic airframe structural criteria demonstrated the potential for significant weight savings while maintaining strength, stability, and damage containment properties of all metal components designed to meet the same criteria.

  15. Crash Simulation of a Vertical Drop Test of a Commuter-Class Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-ft/s (9.14-m/s) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kg) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial code for performing explicit transient dynamic simulations. Predictions of structural deformation and selected time-history responses were generated. The simulation was successfully validated through extensive test-analysis correlation.

  16. Advanced textile applications for primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Jackson, Anthony C.; Barrie, Ronald E.; Shah, Bharat M.; Shukla, Jay G.

    1992-01-01

    Advanced composite primary structural concepts were evaluated for low cost, damage tolerant structures. Development of advanced textile preforms for fuselage structural applications with resin transfer molding and powder epoxy materials are now under development.

  17. Advanced textile applications for primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Jackson, Anthony C.; Barrie, Ronald E.; Shah, Bharat M.; Shukla, Jay G.

    1992-01-01

    Advanced composite primary structural concepts have been evaluated for low cost, damage tolerant structures. Development of advanced textile preforms for fuselage structural applications with resin transfer molding and powder epoxy material is now under development.

  18. Rotor systems research aircraft risk-reduction shake test

    NASA Technical Reports Server (NTRS)

    Wellman, J. Brent

    1990-01-01

    A shake test and an extensive analysis of results were performed to evaluate the possibility of and the method for dynamically calibrating the Rotor Systems Research Aircraft (RSRA). The RSRA airframe was subjected to known vibratory loads in several degrees of freedom and the responses of many aircraft transducers were recorded. Analysis of the transducer responses using the technique of dynamic force determination showed that the RSRA, when used as a dynamic measurement system, could predict, a posteriori, an excitation force in a single axis to an accuracy of about 5 percent and sometimes better. As the analysis was broadened to include multiple degrees of freedom for the excitation force, the predictive ability of the measurement system degraded to about 20 percent, with the error occasionally reaching 100 percent. The poor performance of the measurement system is explained by the nonlinear response of the RSRA to vibratory forces and the inadequacy of the particular method used in accounting for this nonlinearity.

  19. Structural Configuration Systems Analysis for Advanced Aircraft Fuselage Concepts

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, Vivek; Welstead, Jason R.; Quinlan, Jesse R.; Guynn, Mark D.

    2016-01-01

    Structural configuration analysis of an advanced aircraft fuselage concept is investigated. This concept is characterized by a double-bubble section fuselage with rear mounted engines. Based on lessons learned from structural systems analysis of unconventional aircraft, high-fidelity finite-element models (FEM) are developed for evaluating structural performance of three double-bubble section configurations. Structural sizing and stress analysis are applied for design improvement and weight reduction. Among the three double-bubble configurations, the double-D cross-section fuselage design was found to have a relatively lower structural weight. The structural FEM weights of these three double-bubble fuselage section concepts are also compared with several cylindrical fuselage models. Since these fuselage concepts are different in size, shape and material, the fuselage structural FEM weights are normalized by the corresponding passenger floor area for a relative comparison. This structural systems analysis indicates that an advanced composite double-D section fuselage may have a relative structural weight ratio advantage over a conventional aluminum fuselage. Ten commercial and conceptual aircraft fuselage structural weight estimates, which are empirically derived from the corresponding maximum takeoff gross weight, are also presented and compared with the FEM- based estimates for possible correlation. A conceptual full vehicle FEM model with a double-D fuselage is also developed for preliminary structural analysis and weight estimation.

  20. Flight test results for the Daedalus and Light Eagle human powered aircraft

    NASA Technical Reports Server (NTRS)

    Sullivan, R. Bryan; Zerweckh, Siegfried H.

    1988-01-01

    The results of the flight test program of the Daedalus and Light Eagle human powered aircraft in the winter of 1987/88 are given. The results from experiments exploring the Light Eagle's rigid body and structural dynamics are presented. The interactions of these dynamics with the autopilot design are investigated. Estimates of the power required to fly the Daedalus aircraft are detailed. The system of sensors, signal conditioning boards, and data acquisition equipment used to record the flight data is also described. In order to investigate the dynamics of the aircraft, flight test maneuvers were developed to yield maximum data quality from the point of view of estimating lateral and longitudinal stability derivatives. From this data, structural flexibility and unsteady aerodynamics have been modeled in an ad hoc manner and are used to augment the equations of motion with flexibility effects. Results of maneuvers that were flown are compared with the predictions from the flexibility model. To extend the ad hoc flexibility model, a fully flexible aeroelastic model has been developed. The model is unusual in the approximate equality of many structural natural frequencies and the importance of unsteady aerodynamic effects. the Gossamer Albatross. It is hypothesized that this inverse ground effect is caused by turbulence in the Earth's boundary layer. The diameters of the largest boundary layer eddies (which represent most of the turbulent kinetic energy) are proportional to altitude; thus, closer to the ground, the energy in the boundary layer becomes concentrated in eddies of smaller and smaller diameter. Eventually the eddies become sufficiently small (approximately 0.5 cm) that they trip the laminar boundary layer on the wing. As a result, a greater percentage of the wing area is covered with turbulent flow. Consequently the aircraft's drag and the pow er required both increase as the aircraft flies closer to the ground. The results of the flight test program are

  1. A study on the utilization of advanced composites in commercial aircraft wing structure

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composite materials in the wing structure of future production aircraft. The study accomplished the following: (1) definition of acceptance factors, (2) identification of technology issues, (3) evaluation of six candidate wing structures, (4) evaluation of five program options, (5) definition of a composite wing technology development plan, (6) identification of full-scale tests, (7) estimation of program costs for the total development plan, (8) forecast of future utilization of composites in commercial transport aircraft and (9) identification of critical technologies for timely program planning.

  2. Full-scale aircraft cabin flammability tests of improved fire-resistant materials, test series 2

    NASA Technical Reports Server (NTRS)

    Stuckey, R. N.; Bricker, R. W.; Kuminecz, J. F.; Supkis, D. E.

    1976-01-01

    Full-scale aircraft flammability tests in which the effectiveness of new fire-resistant materials was evaluated by comparing their burning characteristics with those of other fire-resistant aircraft materials were described. New-fire-resistant materials that are more economical and better suited for aircraft use than the previously tested fire-resistant materials were tested. The fuel ignition source for one test was JP-4; a smokeless fuel was used for the other test. Test objectives, methods, materials, and results are presented and discussed. The results indicate that, similar to the fire-resistant materials tested previously, the new materials decompose rather than ignite and do not support fire propagation. Furthermore, the new materials did not produce a flash fire.

  3. Comparison of Requirements for Composite Structures for Aircraft and Space Applications

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Elliot, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

    2010-01-01

    In this report, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from aircraft and other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

  4. Test-Analysis Correlation of a Crash Simulation of a Vertical Drop Test of a Commuter-Category Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-feet per second (9.14-meters per second) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kilograms) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, simulated engines and fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial finite element code for performing explicit transient dynamic simulations. Analytical predictions of structural deformation and selected time-history responses were correlated with experimental data from the drop test to validate the simulation.

  5. Autonomous Flight Safety System September 27, 2005, Aircraft Test

    NASA Technical Reports Server (NTRS)

    Simpson, James C.

    2005-01-01

    This report describes the first aircraft test of the Autonomous Flight Safety System (AFSS). The test was conducted on September 27, 2005, near Kennedy Space Center (KSC) using a privately-owned single-engine plane and evaluated the performance of several basic flight safety rules using real-time data onboard a moving aerial vehicle. This test follows the first road test of AFSS conducted in February 2005 at KSC. AFSS is a joint KSC and Wallops Flight Facility (WEF) project that is in its third phase of development. AFSS is an independent subsystem intended for use with Expendable Launch Vehicles that uses tracking data from redundant onboard sensors to autonomously make flight termination decisions using software-based rules implemented on redundant flight processors. The goals of this project are to increase capabilities by allowing launches from locations that do not have or cannot afford extensive ground-based range safety assets, to decrease range costs, and to decrease reaction time for special situations. The mission rules are configured for each operation by the responsible Range Safety authorities and can be loosely categorized in four major categories: Parameter Threshold Violations, Physical Boundary Violations present position and instantaneous impact point (TIP), Gate Rules static and dynamic, and a Green-Time Rule. Examples of each of these rules were evaluated during this aircraft test.

  6. Experimental Validation: Subscale Aircraft Ground Facilities and Integrated Test Capability

    NASA Technical Reports Server (NTRS)

    Bailey, Roger M.; Hostetler, Robert W., Jr.; Barnes, Kevin N.; Belcastro, Celeste M.; Belcastro, Christine M.

    2005-01-01

    Experimental testing is an important aspect of validating complex integrated safety critical aircraft technologies. The Airborne Subscale Transport Aircraft Research (AirSTAR) Testbed is being developed at NASA Langley to validate technologies under conditions that cannot be flight validated with full-scale vehicles. The AirSTAR capability comprises a series of flying sub-scale models, associated ground-support equipment, and a base research station at NASA Langley. The subscale model capability utilizes a generic 5.5% scaled transport class vehicle known as the Generic Transport Model (GTM). The AirSTAR Ground Facilities encompass the hardware and software infrastructure necessary to provide comprehensive support services for the GTM testbed. The ground facilities support remote piloting of the GTM aircraft, and include all subsystems required for data/video telemetry, experimental flight control algorithm implementation and evaluation, GTM simulation, data recording/archiving, and audio communications. The ground facilities include a self-contained, motorized vehicle serving as a mobile research command/operations center, capable of deployment to remote sites when conducting GTM flight experiments. The ground facilities also include a laboratory based at NASA LaRC providing near identical capabilities as the mobile command/operations center, as well as the capability to receive data/video/audio from, and send data/audio to the mobile command/operations center during GTM flight experiments.

  7. Alternative aircraft loading index for pavement structural analysis

    SciTech Connect

    Loizos, A.; Charonitis, G.

    1999-05-01

    The most common practical way to simplify the structural analysis of airfield pavements is the use of equivalent single wheel load models instead of the actual gear of the aircrafts. As the accuracy and reliability of these models strongly affects the design and evaluation of airfield pavements, there is considerable need to investigate both system approaches. The first one, which uses a constant value for the pressure while the radius is variable, is currently under use by the aircraft classification number-pavement classification number method of the International Civil Aviation Organization, but despite this fact it proved to be inadequate to express the aircraft loading in many situations. On the contrary, according to this study, the second model, which has a constant value for the radius while the pressure varies, is more reliable, and it can be an interesting alternative. Thus, based on this model, an aircraft loading index is introduced, which aims to be a simple and reliable factor for expressing the severity of the loading of the aircrafts and a utility for several matters related to the airfield pavement applications.

  8. Design and test of aircraft engine isolators for reduced interior noise

    NASA Technical Reports Server (NTRS)

    Unruh, J. F.; Scheidt, D. C.

    1982-01-01

    Improved engine vibration isolation was proposed to be the most weight and cost efficient retrofit structure-borne noise control measure for single engine general aviation aircraft. A study was carried out the objectives: (1) to develop an engine isolator design specification for reduced interior noise transmission, (2) select/design candidate isolators to meet a 15 dB noise reduction design goal, and (3) carry out a proof of concept evaluation test. Analytical model of the engine, vibration isolators and engine mount structure were coupled to an empirical model of the fuselage for noise transmission evaluation. The model was used to develop engine isolator dynamic properties design specification for reduced noise transmission. Candidate isolators ere chosen from available product literature and retrofit to a test aircraft. A laboratory based test procedure was then developed to simulate engine induced noise transmission in the aircraft for a proof of concept evaluation test. Three candidate isolator configurations were evaluated for reduced structure-borne noise transmission relative to the original equipment isolators.

  9. Wind tunnel and flight test of the XV-15 Tilt Rotor Research Aircraft

    NASA Technical Reports Server (NTRS)

    Marr, R. L.; Blackman, S.; Weiberg, J. A.; Schroers, L. G.

    1979-01-01

    The XV-15 Tilt Rotor Research Aircraft Project involves design, fabrication, and flight testing of two aircraft. This program is currently in the test phase for concept evaluation and substantiation of design. As part of this evaluation, one of the aircraft was tested in the NASA-Ames 40- by 80-foot wind tunnel. The status of testing to date and some of the results of the wind tunnel and flight tests are presented.

  10. Optical Fiber Sensors for Aircraft Structural Health Monitoring.

    PubMed

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-01-01

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel. PMID:26134107

  11. Optical Fiber Sensors for Aircraft Structural Health Monitoring

    PubMed Central

    García, Iker; Zubia, Joseba; Durana, Gaizka; Aldabaldetreku, Gotzon; Illarramendi, María Asunción; Villatoro, Joel

    2015-01-01

    Aircraft structures require periodic and scheduled inspection and maintenance operations due to their special operating conditions and the principles of design employed to develop them. Therefore, structural health monitoring has a great potential to reduce the costs related to these operations. Optical fiber sensors applied to the monitoring of aircraft structures provide some advantages over traditional sensors. Several practical applications for structures and engines we have been working on are reported in this article. Fiber Bragg gratings have been analyzed in detail, because they have proved to constitute the most promising technology in this field, and two different alternatives for strain measurements are also described. With regard to engine condition evaluation, we present some results obtained with a reflected intensity-modulated optical fiber sensor for tip clearance and tip timing measurements in a turbine assembled in a wind tunnel. PMID:26134107

  12. Aircraft ground vibration testing at the NASA Dryden Flight Research Facility, 1993

    NASA Technical Reports Server (NTRS)

    Kehoe, Michael W.; Freudinger, Lawrence C.

    1994-01-01

    The NASA Dryden Flight Research Facility performs ground vibration testing to assess the structural characteristics of new and modified research vehicles. This paper updates the research activities, techniques used, and experiences in applying this technology to aircraft since 1987. Test equipment, data analysis methods, and test procedures used for typical test programs are discussed. The data presented illustrate the use of modal test and analysis in flight research programs for a variety of aircraft. This includes a technique to acquire control surface free-play measurements on the X-31 airplane more efficiently, and to assess the effects of structural modifications on the modal characteristics of an F-18 aircraft. In addition, the status and results from current research activities are presented. These data show the effectiveness of the discrete modal filter as a preprocessor to uncouple response measurements into simple single-degree-of-freedom responses, a database for the comparison of different excitation methods on a JetStar airplane, and the effect of heating on modal frequency and damping.

  13. Review of measurement and testing problems. [of aircraft emissions

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Good instrumentation was required to obtain reliable and repeatable baseline data. Problems that were encountered in developing such a total system were: (1) accurate airflow measurement, (2) precise fuel flow measurement, and (3) the instrumentation used for pollutant measurement was susceptible to frequent malfunctions. Span gas quality had a significant effect on emissions test results. The Spindt method was used in the piston aircraft emissions program. The Spindt method provided a comparative computational procedure for fuel/air ratio based on measured emissions concentrations.

  14. Electrical short circuit and current overload tests on aircraft wiring

    NASA Technical Reports Server (NTRS)

    Cahill, Patricia

    1995-01-01

    The findings of electrical short circuit and current overload tests performed on commercial aircraft wiring are presented. A series of bench-scale tests were conducted to evaluate circuit breaker response to overcurrent and to determine if the wire showed any visible signs of thermal degradation due to overcurrent. Three types of wire used in commercial aircraft were evaluated: MIL-W-22759/34 (150 C rated), MIL-W-81381/12 (200 C rated), and BMS 1360 (260 C rated). A second series of tests evaluated circuit breaker response to short circuits and ticking faults. These tests were also meant to determine if the three test wires behaved differently under these conditions and if a short circuit or ticking fault could start a fire. It is concluded that circuit breakers provided reliable overcurrent protection. Circuit breakers may not protect wire from ticking faults but can protect wire from direct shorts. These tests indicated that the appearance of a wire subjected to a current that totally degrades the insulation looks identical to a wire subjected to a fire; however the 'fire exposed' conductor was more brittle than the conductor degraded by overcurrent. Preliminary testing indicates that direct short circuits are not likely to start a fire. Preliminary testing indicated that direct short circuits do not erode insulation and conductor to the extent that ticking faults did. Circuit breakers may not safeguard against the ignition of flammable materials by ticking faults. The flammability of materials near ticking faults is far more important than the rating of the wire insulation material.

  15. Design considerations for composite fuselage structure of commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Davis, G. W.; Sakata, I. F.

    1981-01-01

    The structural, manufacturing, and service and environmental considerations that could impact the design of composite fuselage structure for commercial transport aircraft application were explored. The severity of these considerations was assessed and the principal design drivers delineated. Technical issues and potential problem areas which must be resolved before sufficient confidence is established to commit to composite materials were defined. The key issues considered are: definition of composite fuselage design specifications, damage tolerance, and crashworthiness.

  16. Hybrid Wing Body Aircraft Acoustic Test Preparations and Facility Upgrades

    NASA Technical Reports Server (NTRS)

    Heath, Stephanie L.; Brooks, Thomas F.; Hutcheson, Florence V.; Doty, Michael J.; Haskin, Henry H.; Spalt, Taylor B.; Bahr, Christopher J.; Burley, Casey L.; Bartram, Scott M.; Humphreys, William M.; Lunsford, Charles B.; Popenack, Thomas G.; Colbert, Scott E.; Hoad, Danny; Becker, Lawrence; Stead, Dan; Kuchta, Dennis; Yeh, Les

    2013-01-01

    NASA is investigating the potential of acoustic shielding as a means to reduce the noise footprint at airport communities. A subsonic transport aircraft and Langley's 14- by 22-foot Subsonic Wind Tunnel were chosen to test the proposed "low noise" technology. The present experiment studies the basic components of propulsion-airframe shielding in a representative flow regime. To this end, a 5.8-percent scale hybrid wing body model was built with dual state-of-the-art engine noise simulators. The results will provide benchmark shielding data and key hybrid wing body aircraft noise data. The test matrix for the experiment contains both aerodynamic and acoustic test configurations, broadband turbomachinery and hot jet engine noise simulators, and various airframe configurations which include landing gear, cruise and drooped wing leading edges, trailing edge elevons and vertical tail options. To aid in this study, two major facility upgrades have occurred. First, a propane delivery system has been installed to provide the acoustic characteristics with realistic temperature conditions for a hot gas engine; and second, a traversing microphone array and side towers have been added to gain full spectral and directivity noise characteristics.

  17. Flight Test Results on the Stability and Control of the F-15B Quiet Spike Aircraft

    NASA Technical Reports Server (NTRS)

    Moua, Cheng; McWherter, Shaun H.; Cox, Timothy H.; Gera, Joseph

    2007-01-01

    The Quiet Spike (QS) flight research program was an aerodynamic and structural proof-of-concept of a telescoping sonic-boom suppressing nose boom on an F-15 B aircraft. The program goal was to collect flight data for model validation up to 1.8 Mach. The primary test philosophy was maintaining safety of flight. In the area of stability and controls the primary concerns were to assess the potential destabilizing effect of the spike on the stability, controllability, and handling qualities of the aircraft and to ensure adequate stability margins across the entire QS flight envelop. This paper reports on the stability and control methods used for flight envelope clearance and flight test results of the F-15B Quiet Spike. Also discussed are the flight test approach, the criteria to proceed to the next flight condition, brief pilot commentary on typical piloting tasks, approach and landing, and refueling task, and air data sensitivity to the flight control system.

  18. Peripheral vision horizon display testing in RF-4C aircraft

    NASA Technical Reports Server (NTRS)

    Hammond, L. B., Jr.

    1984-01-01

    A test program to assess the capability of the peripheral vision horizon display (PVHD) to provide peripheral attitude cues to the pilot is described. The system was installed in the rear cockpit of a RF-4C aircraft, selected because its poor instrument crosscheck conditions. The PVHD test plan was designed to assess three primary areas: (1) ability of the system to reduce spatial disorientation; (2) ability of the system to aid the pilot in recovering from unusual attitudes; and (3) improvement in pilot performance during instrument landing system (ILS) approaches. Results of preliminary test flights are summarized. The major problem areas concern the distinction of the display itself and the capability of the display to provide pitch motion cues.

  19. Environmental assessment, aircraft chemical warfare survivability test program, Naval Air Warfare Center, Aircraft Division, Patuxent River, Maryland

    SciTech Connect

    1992-02-01

    The proposed project, the Aircraft Chemical Warfare Survivability Test Program at Patuxent River Naval Air Station, involves the testing and development of aircraft systems and operating procedures for use in an environment contaminated with chemical/biological warfare agents. The tests will be performed in accordance with a directive from the chief of Naval Operations to obtain and maintain the capability to operate in a chemically-contaminated environment. These tests will be performed under outdoor, warm-weather conditions on a dredge disposal area and adjacent runways to simulate the conditions under which a real-life threat would be encountered.

  20. Development of advanced structural analysis methodologies for predicting widespread fatigue damage in aircraft structures

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Starnes, James H., Jr.; Newman, James C., Jr.

    1995-01-01

    NASA is developing a 'tool box' that includes a number of advanced structural analysis computer codes which, taken together, represent the comprehensive fracture mechanics capability required to predict the onset of widespread fatigue damage. These structural analysis tools have complementary and specialized capabilities ranging from a finite-element-based stress-analysis code for two- and three-dimensional built-up structures with cracks to a fatigue and fracture analysis code that uses stress-intensity factors and material-property data found in 'look-up' tables or from equations. NASA is conducting critical experiments necessary to verify the predictive capabilities of the codes, and these tests represent a first step in the technology-validation and industry-acceptance processes. NASA has established cooperative programs with aircraft manufacturers to facilitate the comprehensive transfer of this technology by making these advanced structural analysis codes available to industry.

  1. Design, ancillary testing, analysis and fabrication data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1982-01-01

    Results of tests conducted to demonstrate that composite structures save weight, possess long term durability, and can be fabricated at costs competitive with conventional metal structures are presented with focus on the use of graphite-epoxy in the design of a stabilizer for the Boeing 737 aircraft. Component definition, materials evaluation, material design properties, and structural elements tests are discussed. Fabrication development, as well as structural repair and inspection are also examined.

  2. Finite Element Model Development For Aircraft Fuselage Structures

    NASA Technical Reports Server (NTRS)

    Buehrle, Ralph D.; Fleming, Gary A.; Pappa, Richard S.; Grosveld, Ferdinand W.

    2000-01-01

    The ability to extend the valid frequency range for finite element based structural dynamic predictions using detailed models of the structural components and attachment interfaces is examined for several stiffened aircraft fuselage structures. This extended dynamic prediction capability is needed for the integration of mid-frequency noise control technology. Beam, plate and solid element models of the stiffener components are evaluated. Attachment models between the stiffener and panel skin range from a line along the rivets of the physical structure to a constraint over the entire contact surface. The finite element models are validated using experimental modal analysis results.

  3. Mechanical paint removal techniques for aircraft structures

    NASA Astrophysics Data System (ADS)

    Amro, Joe P.; Talia, Jorge E.

    1990-05-01

    Paint removal by mechanical means, i.e., blasting, from aluminum structural aeronautical materials (2024-T3) was examined alone with the changes on the surface morphology introduced by the paint removal process. Three types of plastic particles were used in this research: Polyextra, Polyplus, and Type III. Scanning electron microscopy has shown that a potentially damaging surface morphology is formed on the surface of the structural material. Multiple microcracks or fissures generated by the stripping could reduce the life and/or change the engineering properties of the material. It was also found that aluminum material stripped using plastic media particles has a very rough surface that may affect the aerodynamic flow of an airplane. The number of microcracks and degree of surface roughness vary with the particle impact angle and velocity. To minimize or eliminate the damage done to the surface during the plastic particle stripping, it was necessary to change the blasting media to softer and smaller particles. Commercial wheat flour was selected for this purpose. With the substitution of these natural particles, the scanning electron microscopy observations of the stripped surface revealed no potential damage (microcracks or fissures) on the structural material, and the surface roughness was also reduced.

  4. PTA test bed aircraft engine inlet model test report, revised

    NASA Technical Reports Server (NTRS)

    Hancock, J. P.

    1985-01-01

    The inlet duct test for the Propfan Testbed Assessment (PTA) program was completed in November 1984. The basic test duct was designed using the Lockheed QUADPAN computational code. Test objectives were to experimentally evaluate, modify as required, and eventually verify satisfactory performance as well as duct/engine compatibility. Measured total pressure recovery for the basic duct was 0.993 with no swirl and 0.989 for inflow with a 30 degree simulated swirl angle. This compared to a predicted recovery of 0.979 with no swirl. Measured circumferential distortion with swirl, based on a least-square curve fit of the data, was 0.204 compared to a maximum allowable value of 0.550. Other measured distortion parameters did as well or better relative to their respective maximum allowable values. The basic duct configuration with no refinements is recommended for the PTA inlet as a minimum cost installation.

  5. Laser beam welding of high stressed, complex aircraft structural parts

    NASA Astrophysics Data System (ADS)

    Mueller-Hummel, Peter; Ferstl, Stefan; Sengotta, Marcus; Lang, Roland

    2003-03-01

    Laser beam welding of primary aircraft structures manufactured from aluminum alloys is considered to have a great potential in cost saving. In order to evaluate this advantage, a technology program has been adopted at EADS, Military Aircraft. The goal was to manufacture air intake shells for the Eurofighter in a cost efficient way. Stretch formed skins and machined stiffeners are joined together with laser beam welding. The baseline for a comparison in terms of cost and weight was the conventional process based on stretch forming of thick plates and subsequent milling. The major tasks of the program have been the optimization of the twin focus laser beam welding process and the proof of the structural integrity including weld strength evaluation.

  6. Status of Advanced Stitched Unitized Composite Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.; Velicki, Alex

    2013-01-01

    NASA has created the Environmentally Responsible Aviation (ERA) Project to explore and document the feasibility, benefits and technical risk of advanced vehicle configurations and enabling technologies that will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations that have higher lift-to-drag ratios, reduced drag, and lower community noise levels. The primary structural concept being developed under the ERA project in the Airframe Technology element is the Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept. This paper describes how researchers at NASA and The Boeing Company are working together to develop fundamental PRSEUS technologies that could someday be implemented on a transport size aircraft with high aspect ratio wings or unconventional shapes such as a hybrid wing body airplane design.

  7. Lamb Wave Based Structural Health Monitoring of Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Pereira da Silva, Carlos Manuel Baptista

    Structural Health Monitoring (SHM) through adequate damage detection and prediction of the remaining useful life of structures is a major area of interest in the aerospace community, where the growing maintenance costs can reduce the operational life of flight vehicles. The objective of a SHM system with an advanced diagnostic capability is to gradually replace current schedule-based maintenance tasks, where components are inspected following a pre-established number of cycles using condition-based maintenance, or are maintained prior to attaining an insufficient remaining useful life, based on specified confidence bounds. The research challenge is to obtain a reliable method for determining damage existence and respective location during its initial growth state as a component of an early warning system. In this thesis, an SHM system based on Lamb waves is proposed. A damage detection algorithm based on the comparison between the damaged structural state and a reference state has been developed. The detection algorithm, based on discrete signals correlation, was tested and improved by incorporating statistical methods and domain division techniques. Two SHM system architectures, namely the sensor network and phased array system were designed, implemented and tested. A visualization method based on the superposition of solutions obtained from a test set was implemented. Tests executed with multiple damage, representing surface and through-the-thickness holes and cracks were performed. The proposed SHM systems using Lamb waves were able to reliably detect holes of 1 mm holes in aluminum and 1.5 mm in composite plates with great confidence.

  8. Feedback Linearized Aircraft Control Using Dynamic Cell Structure

    NASA Technical Reports Server (NTRS)

    Jorgensen, C. C.

    1998-01-01

    A Dynamic Cell Structure (DCS ) Neural Network was developed which learns a topology representing network (TRN) of F-15 aircraft aerodynamic stability and control derivatives. The network is combined with a feedback linearized tracking controller to produce a robust control architecture capable of handling multiple accident and off-nominal flight scenarios. This paper describes network and its performance for accident scenarios including differential stabilator lock, soft sensor failure, control, stability derivative variation, and turbulence.

  9. Development of Textile Reinforced Composites for Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. Benson

    1998-01-01

    NASA has been a leader in development of composite materials for aircraft applications during the past 25 years. In the early 1980's NASA and others conducted research to improve damage tolerance of composite structures through the use of toughened resins but these resins were not cost-effective. The aircraft industry wanted affordable, robust structures that could withstand the rigors of flight service with minimal damage. The cost and damage tolerance barriers of conventional laminated composites led NASA to focus on new concepts in composites which would incorporate the automated manufacturing methods of the textiles industry and which would incorporate through-the-thickness reinforcements. The NASA Advanced Composites Technology (ACT) Program provided the resources to extensively investigate the application of textile processes to next generation aircraft wing and fuselage structures. This paper discusses advanced textile material forms that have been developed, innovative machine concepts and key technology advancements required for future application of textile reinforced composites in commercial transport aircraft. Multiaxial warp knitting, triaxial braiding and through-the-thickness stitching are the three textile processes that have surfaced as the most promising for further development. Textile reinforced composite structural elements that have been developed in the NASA ACT Program are discussed. Included are braided fuselage frames and window-belt reinforcements, woven/stitched lower fuselage side panels, stitched multiaxial warp knit wing skins, and braided wing stiffeners. In addition, low-cost processing concepts such as resin transfer molding (RTM), resin film infusion (RFI), and vacuum-assisted resin transfer molding (VARTM) are discussed. Process modeling concepts to predict resin flow and cure in textile preforms are also discussed.

  10. Overview Of Structural Behavior and Occupant Responses from Crash Test of a Composite Airplane

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Carden, Huey D.

    1995-01-01

    As part of NASA's composite structures crash dynamics research, a general aviation aircraft with composite wing, fuselage and empennage (but with metal subfloor structure) was crash tested at the NASA Langley Research Center Impact Research Facility. The test was conducted to determine composite aircraft structural behavior for crash loading conditions and to provide a baseline for a similar aircraft test with a modified subfloor. Structural integrity and cabin volume were maintained. Lumbar loads for dummy occupants in energy absorbing seats wer substantially lower than those in standard aircraft seats; however, loads in the standard seats were much higher that those recorded under similar conditions for an all-metallic aircraft.

  11. Life determination of riveted aircraft structure by holographic NDE

    NASA Astrophysics Data System (ADS)

    Baird, John P.; Heslehurst, Rikard B.; Williamson, Hugh M.; Clark, Robert K.; Hollamby, Derek

    1996-11-01

    In a project funded by the Federal Aviation Administration's (FAA) Aging Aircraft Program, a Portable Holographic Inspection System (PHITS) has been further developed. The technique involves taking a double exposure white light reflection hologram of aircraft structures. Each exposure is taken at a slightly different load state, and the resulting interferogram shows the deformations that occur between the two load states. Results showed that the rivets in a simple lap joint, designed to simulate the longitudinal lap splice on a Boeing 737, behaved in two distinct and easily recognizable modes. The first mode occurred at low loads and was an indication that friction forces between the two sheets of the lap joint dominated the load transfer mechanism. Indications were that the second mode related to higher loads for which the friction forces played a much lesser role. The load at which the changeover begins to occur has been called the critical load. Preliminary experiments showed that structures with a high value of critical load had a fatigue life of order ten times that of a normally fastened splice. Critical load can be readily determined in the field using the PHITS system. Research designed to establish the relationship between fatigue life and critical load is continuing. An understanding of that relationship could lead to a technique capable of fatigue life determination in typical aircraft structures.

  12. Impact Analyses and Tests of Metal Cask Considering Aircraft Engine Crash - 12308

    SciTech Connect

    Lee, Sanghoon; Choi, Woo-Seok; Kim, Ki-Young; Jeon, Je-Eon; Seo, Ki-Seog

    2012-07-01

    The structural integrity of a dual purpose metal cask currently under development by the Korea Radioactive Waste Management Cooperation (KRMC) is evaluated through analyses and tests under a high-speed missile impact considering the targeted aircraft crash conditions. The impact conditions were carefully chosen through a survey on accident cases and recommendations from the literature. The missile impact velocity was set at 150 m/s, and two impact orientations were considered. A simplified missile simulating a commercial aircraft engine is designed from an impact load history curve provided in the literature. In the analyses, the focus is on the evaluation of the containment boundary integrity of the metal cask. The analyses results are compared with the results of tests using a 1/3 scale model. The results show very good agreements, and the procedure and methodology adopted in the structural analyses are validated. While the integrity of the cask is maintained in one evaluation where the missile impacts the top side of the free standing cask, the containment boundary is breached in another case in which the missile impacts the center of the cask lid in a perpendicular orientation. A safety assessment using a numerical simulation of an aircraft engine crash into spent nuclear fuel storage systems is performed. A commercially available explicit finite element code is utilized for the dynamic simulation, and the strain rate effect is included in the modeling of the materials used in the target system and missile. The simulation results show very good agreement with the test results. It is noted that this is the first test considering an aircraft crash in Korea. (authors)

  13. Aircraft fiber optic structural health monitoring

    NASA Astrophysics Data System (ADS)

    Mrad, Nezih

    2012-06-01

    Structural Health Monitoring (SHM) is a sought after concept that is expected to advance military maintenance programs, increase platform operational safety and reduce its life cycle cost. Such concept is further considered to constitute a major building block of any Integrated Health Management (IHM) capability. Since 65% to 80% of military assets' Life Cycle Cost (LCC) is devoted to operations and support (O&S), the aerospace industry and military sectors continue to look for opportunities to exploit SHM systems, capability and tools. Over the past several years, countless SHM concepts and technologies have emerged. Among those, fiber optic based systems were identified of significant potential. This paper introduces the elements of an SHM system and investigates key issues impeding the commercial implementation of fiber optic based SHM capability. In particular, this paper presents an experimental study of short gauge, intrinsic, spectrometric-based in-fiber Bragg grating sensors, for potential use as a component of an SHM system. Fiber optic Bragg grating sensors are evaluated against resistance strain gauges for strain monitoring, sensitivity, accuracy, reliability, and fatigue durability. Strain field disturbance is also investigated by "embedding" the sensors under a photoelastic coating in order to illustrate sensor intrusiveness in an embedded configuration.

  14. Load test set-up for the Airmass Sunburst Ultra-Light Aircraft

    NASA Technical Reports Server (NTRS)

    Krug, Daniel W.; Smith, Howard W.

    1993-01-01

    The purpose of this project was to set up, instrument, and test a Sunburst Ultra-Light aircraft. The intentions of the project were that the aircraft would need to be suspended from the test stand, leveled in the stand, the strain gauges tested and wired to the test equipment, and finally, the aircraft would be destroyed to obtain the failing loads. All jobs were completed, except for the destruction of the aircraft. This notebook shows the group's progress as these tasks were completed, and the following section attempts to explain the photographs in the notebook.

  15. Structural analysis of ultra-high speed aircraft structural components

    NASA Technical Reports Server (NTRS)

    Lenzen, K. H.; Siegel, W. H.

    1977-01-01

    The buckling characteristics of a hypersonic beaded skin panel were investigated under pure compression with boundary conditions similar to those found in a wing mounted condition. The primary phases of analysis reported include: (1) experimental testing of the panel to failure; (2) finite element structural analysis of the beaded panel with the computer program NASTRAN; and (3) summary of the semiclassical buckling equations for the beaded panel under purely compressive loads. A comparison of each of the analysis methods is also included.

  16. Development of Stitched Composite Structure for Advanced Aircraft

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn; Przekop, Adam; Rouse, Marshall; Lovejoy, Andrew; Velicki, Alex; Linton, Kim; Wu, Hsi-Yung; Baraja, Jaime; Thrash, Patrick; Hoffman, Krishna

    2015-01-01

    NASA has created the Environmentally Responsible Aviation Project to develop technologies which will reduce the impact of aviation on the environment. A critical aspect of this pursuit is the development of a lighter, more robust airframe that will enable the introduction of unconventional aircraft configurations. NASA and The Boeing Company are working together to develop a structural concept that is lightweight and an advancement beyond state-of-the-art composites. The Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) is an integrally stiffened panel design where elements are stitched together and designed to maintain residual load-carrying capabilities under a variety of damage scenarios. With the PRSEUS concept, through-the-thickness stitches are applied through dry fabric prior to resin infusion, and replace fasteners throughout each integral panel. Through-the-thickness reinforcement at discontinuities, such as along flange edges, has been shown to suppress delamination and turn cracks, which expands the design space and leads to lighter designs. The pultruded rod provides stiffening away from the more vulnerable skin surface and improves bending stiffness. A series of building blocks were evaluated to explore the fundamental assumptions related to the capability and advantages of PRSEUS panels. These building blocks addressed tension, compression, and pressure loading conditions. The emphasis of the development work has been to assess the loading capability, damage arrestment features, repairability, post-buckling behavior, and response of PRSEUS flat panels to out-of plane pressure loading. The results of this building-block program from coupons through an 80%-scale pressure box have demonstrated the viability of a PRSEUS center body for the Hybrid Wing Body (HWB) transport aircraft. This development program shows that the PRSEUS benefits are also applicable to traditional tube-andwing aircraft, those of advanced configurations, and other

  17. 77 FR 36341 - Control of Air Pollution From Aircraft and Aircraft Engines; Emission Standards and Test Procedures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ...). \\17\\ U.S. EPA, ``Emission Standards and Test Procedures for Aircraft;'' Final Rule, 38 FR 19088, July... Standards and Test Procedures;'' Final Rule, 62 FR 25356, May 8, 1997. While ICAO's standards were not... pollution which may reasonably be anticipated to endanger public health or welfare was so limited, See 62...

  18. Self Diagnostic Accelerometer Ground Testing on a C-17 Aircraft Engine

    NASA Technical Reports Server (NTRS)

    Tokars, Roger P.; Lekki, John D.

    2013-01-01

    The self diagnostic accelerometer (SDA) developed by the NASA Glenn Research Center was tested for the first time in an aircraft engine environment as part of the Vehicle Integrated Propulsion Research (VIPR) program. The VIPR program includes testing multiple critical flight sensor technologies. One such sensor, the accelerometer, measures vibrations to detect faults in the engine. In order to rely upon the accelerometer, the health of the accelerometer must be ensured. Sensor system malfunction is a significant contributor to propulsion in flight shutdowns (IFSD) which can lead to aircraft accidents when the issue is compounded with an inappropriate crew response. The development of the SDA is important for both reducing the IFSD rate, and hence reducing the rate at which this component failure type can put an aircraft in jeopardy, and also as a critical enabling technology for future automated malfunction diagnostic systems. The SDA is a sensor system designed to actively determine the accelerometer structural health and attachment condition, in addition to making vibration measurements. The SDA uses a signal conditioning unit that sends an electrical chirp to the accelerometer and recognizes changes in the response due to changes in the accelerometer health and attachment condition. In an effort toward demonstrating the SDAs flight worthiness and robustness, multiple SDAs were mounted and tested on a C-17 aircraft engine. The engine test conditions varied from engine off, to idle, to maximum power. The two SDA attachment conditions used were fully tight and loose. The newly developed SDA health algorithm described herein uses cross correlation pattern recognition to discriminate a healthy from a faulty SDA. The VIPR test results demonstrate for the first time the robustness of the SDA in an engine environment characterized by high vibration levels.

  19. Self diagnostic accelerometer ground testing on a C-17 aircraft engine

    NASA Astrophysics Data System (ADS)

    Tokars, Roger P.; Lekki, John D.

    The self diagnostic accelerometer (SDA) developed by the NASA Glenn Research Center was tested for the first time in an aircraft engine environment as part of the Vehicle Integrated Propulsion Research (VIPR) program. The VIPR program includes testing multiple critical flight sensor technologies. One such sensor, the accelerometer, measures vibrations to detect faults in the engine. In order to rely upon the accelerometer, the health of the accelerometer must be ensured. Sensor system malfunction is a significant contributor to propulsion in flight shutdowns (IFSD) which can lead to aircraft accidents when the issue is compounded with an inappropriate crew response. The development of the SDA is important for both reducing the IFSD rate, and hence reducing the rate at which this component failure type can put an aircraft in jeopardy, and also as a critical enabling technology for future automated malfunction diagnostic systems. The SDA is a sensor system designed to actively determine the accelerometer structural health and attachment condition, in addition to making vibration measurements. The SDA uses a signal conditioning unit that sends an electrical chirp to the accelerometer and recognizes changes in the response due to changes in the accelerometer health and attachment condition. In an effort toward demonstrating the SDA's flight worthiness and robustness, multiple SDAs were mounted and tested on a C-17 aircraft engine. The engine test conditions varied from engine off, to idle, to maximum power. The two SDA attachment conditions used were fully tight and loose. The newly developed SDA health algorithm described herein uses cross correlation pattern recognition to discriminate a healthy from a faulty SDA. The VIPR test results demonstrate for the first time the robustness of the SDA in an engine environment characterized by high vibration levels.

  20. Rolling flow wind tunnel tests of F-18 aircraft

    NASA Technical Reports Server (NTRS)

    Lutze, F. H.

    1980-01-01

    The lateral directional characteristics of an F-18 aircraft was investigated. Aerodynamic derivatives associated with pure roll rate, or the 'p' derivatives were obtained. The model is described and the procedures used to obtain and correct the data, and a graphical presentation of the results are presented. These results include graphs of the lateral directional static stability derivatives versus angle of attack, and the lateral directional force and moment coefficients versus nondimensional roll rate. Results are presented for several configurations including complete, complete without vertical tails, complete without horizontal tails, fuselage wing and fuselage alone. Each of these configuations was tested with and without wing leading edge extensions. The basic control surfaces were deflected and the results were investigated.

  1. Specification and testing for power by wire aircraft

    NASA Technical Reports Server (NTRS)

    Hansen, Irving G.; Kenney, Barbara H.

    1993-01-01

    A power by wire aircraft is one in which all active functions other than propulsion are implemented electrically. Other nomenclature are 'all electric airplane,' or 'more electric airplane.' What is involved is the task of developing and certifying electrical equipment to replace existing hydraulics and pneumatics. When such functions, however, are primary flight controls which are implemented electrically, new requirements are imposed that were not anticipated by existing power system designs. Standards of particular impact are the requirements of ultra-high reliability, high peak transient bi-directional power flow, and immunity to electromagnetic interference and lightning. Not only must the electromagnetic immunity of the total system be verifiable, but box level tests and meaningful system models must be established to allow system evaluation. This paper discusses some of the problems, the system modifications involved, and early results in establishing wiring harness and interface susceptibility requirements.

  2. Specification and testing for power by wire aircraft

    NASA Astrophysics Data System (ADS)

    Hansen, Irving G.; Kenney, Barbara H.

    1993-08-01

    A power by wire aircraft is one in which all active functions other than propulsion are implemented electrically. Other nomenclature are 'all electric airplane,' or 'more electric airplane.' What is involved is the task of developing and certifying electrical equipment to replace existing hydraulics and pneumatics. When such functions, however, are primary flight controls which are implemented electrically, new requirements are imposed that were not anticipated by existing power system designs. Standards of particular impact are the requirements of ultra-high reliability, high peak transient bi-directional power flow, and immunity to electromagnetic interference and lightning. Not only must the electromagnetic immunity of the total system be verifiable, but box level tests and meaningful system models must be established to allow system evaluation. This paper discusses some of the problems, the system modifications involved, and early results in establishing wiring harness and interface susceptibility requirements.

  3. Autonomous earth feature classification - Shuttle and aircraft flight test results

    NASA Technical Reports Server (NTRS)

    Sivertson, W. E., Jr.; Wilson, R. G.; Bullock, G. F.

    1983-01-01

    The Feature Identification and Location Experiment (FILE) flown on the Shuttle STS-2 mission November 12-14, 1981, tested a technique for autonomous real-time classification of selected earth features, i.e., water; bare land; vegetation; and clouds, snow, and ice. A second instrument, designed for aircraft flights, flew over regions of the west and east coasts of the United States and across the country. In each instrument, two bore-sighted CCD cameras image earth scenes in two spectral bands. Each camera includes a 100-element by 100-element detector array, and classification circuits. A simple algorithm and logic circuit provides classification decisions within a few microseconds. The experiment records the number of picture elements (pixels) representing each feature and the reflected solar radiation for each band. After flight, pixel-by-pixel classification images are constructed and compared with 70-mm color photographs taken simultaneously with the CCD-camera data.

  4. Curved flow wind tunnnel test of F-18 aircraft

    NASA Technical Reports Server (NTRS)

    Lutze, F. H.

    1980-01-01

    The curved flow capability of a stability wind tunnel was used to investigate the lateral directional characteristics of an F-18 aircraft. The model is described and the procedures used to obtain and correct the data and a graphical presentation of the results are presented. The results include graphs of lateral directional derivatives versus sideslip or static plots, the lateral directional static stability derivatives versus angle of attack, and finally the lateral directional derivatives versus nondimensional yaw rate for different angles of attack and sideslip. Results are presented for several configurations including complete, complete without vertical tails, complete without horizontal tails, fuselage wing and fuselage alone. Each of these were tested with and without wing leading edge extensions.

  5. Direct Adaptive Aircraft Control Using Dynamic Cell Structure Neural Networks

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C.

    1997-01-01

    A Dynamic Cell Structure (DCS) Neural Network was developed which learns topology representing networks (TRNS) of F-15 aircraft aerodynamic stability and control derivatives. The network is integrated into a direct adaptive tracking controller. The combination produces a robust adaptive architecture capable of handling multiple accident and off- nominal flight scenarios. This paper describes the DCS network and modifications to the parameter estimation procedure. The work represents one step towards an integrated real-time reconfiguration control architecture for rapid prototyping of new aircraft designs. Performance was evaluated using three off-line benchmarks and on-line nonlinear Virtual Reality simulation. Flight control was evaluated under scenarios including differential stabilator lock, soft sensor failure, control and stability derivative variations, and air turbulence.

  6. Fuzzy Structures Analysis of Aircraft Panels in NASTRAN

    NASA Technical Reports Server (NTRS)

    Sparrow, Victor W.; Buehrle, Ralph D.

    2001-01-01

    This paper concerns an application of the fuzzy structures analysis (FSA) procedures of Soize to prototypical aerospace panels in MSC/NASTRAN, a large commercial finite element program. A brief introduction to the FSA procedures is first provided. The implementation of the FSA methods is then disclosed, and the method is validated by comparison to published results for the forced vibrations of a fuzzy beam. The results of the new implementation show excellent agreement to the benchmark results. The ongoing effort at NASA Langley and Penn State to apply these fuzzy structures analysis procedures to real aircraft panels is then described.

  7. Aircraft fatigue and crack growth considering loads by structural component

    NASA Technical Reports Server (NTRS)

    Yost, J. D.

    1994-01-01

    The indisputable 1968 C-130 fatigue/crack growth data is reviewed to obtain additional useful information on fatigue and crack growth. The proven Load Environment Model concept derived empirically from F-105D multichannel recorder data is refined to a simpler method by going from 8 to 5 variables in the spectra without a decrease in accuracy. This approach provides the true fatigue/crack growth and load environment by structural component for both fatigue and strength design. Methods are presented for defining fatigue scatter and damage at crack initiation. These design tools and criteria may be used for both metal and composite aircraft structure.

  8. Aircraft landing dynamics facility carriage weld test program

    NASA Technical Reports Server (NTRS)

    Lawson, A. G.

    1984-01-01

    A welded tubular structure constructed of low alloy high strength quenched and tempered steel was tested. The consistency of the mechanical strengths and chemical composition and the degree of difficulty of obtaining full strength welds with these steels is characterized. The results of constructing and testing two typical connections which are used in the structure design are reported.

  9. On structural health monitoring of aircraft adhesively bonded repairs

    NASA Astrophysics Data System (ADS)

    Pavlopoulou, Sofia

    The recent interest in life extension of ageing aircraft and the need to address the repair challenges in the new age composite ones, led to the investigation of new repair methodologies such as adhesively bonded repair patches. The present thesis focuses on structural health monitoring aspects of the repairs, evaluating their performance with guided ultrasonic waves aiming to develop a monitoring strategy which would eliminate unscheduled maintenance and unnecessary inspection costs. To address the complex nature of the wave propagation phenomena, a finite element based model identified the existing challenges by exploring the interaction of the excitation waves with different levels of damage. The damage sensitivity of the first anti-symmetric mode was numerically investigated. An external bonded patch and a scarf repair, were further tested in static and dynamic loadings, and their performance was monitored with Lamb waves, excited by surface-bonded piezoelectric transducers.. The response was processed by means of advanced pattern recognition and data dimension reduction techniques such as novelty detection and principal component analysis. An optimisation of these tools enabled an accurate damage detection under complex conditions. The phenomena of mode isolation and precise arrival time determination under a noisy environment and the problem of inadequate training data were investigated and solved through appropriate transducer arrangements and advanced signal processing respectively. The applicability of the established techniques was demonstrated on an aluminium repaired helicopter tail stabilizer. Each case study utilised alternative non-destructive techniques for validation such as 3D digital image correlation, X-ray radiography and thermography. Finally a feature selection strategy was developed through the analysis of the instantaneous properties of guided waves for damage detection purposes..

  10. A fuselage/tank structure study for actively cooled hypersonic cruise vehicles, summary. [aircraft design of aircraft fuel systems

    NASA Technical Reports Server (NTRS)

    Pirrello, C. J.; Baker, A. H.; Stone, J. E.

    1976-01-01

    A detailed analytical study was made to investigate the effects of fuselage cross section (circular and elliptical) and the structural arrangement (integral and nonintegral tanks) on aircraft performance. The vehicle was a 200 passenger, liquid hydrogen fueled Mach 6 transport designed to meet a range goal of 9.26 Mn (5000 NM). A variety of trade studies were conducted in the area of configuration arrangement, structural design, and active cooling design in order to maximize the performance of each of three point design aircraft: (1) circular wing-body with nonintegral tanks, (2) circular wing-body with integral tanks and (3) elliptical blended wing-body with integral tanks. Aircraft range and weight were used as the basis for comparison. The resulting design and performance characteristics show that the blended body integral tank aircraft weights the least and has the greatest range capability, however, producibility and maintainability factors favor nonintegral tank concepts.

  11. NASA Boeing 737 Aircraft Test Results from 1996 Joint Winter Runway Friction Measurement Program

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1996-01-01

    A description of the joint test program objectives and scope is given together with the performance capability of the NASA Langley B-737 instrumented aircraft. The B-737 test run matrix conducted during the first 8 months of this 5-year program is discussed with a description of the different runway conditions evaluated. Some preliminary test results are discussed concerning the Electronic Recording Decelerometer (ERD) readings and a comparison of B-737 aircraft braking performance for different winter runway conditions. Detailed aircraft parameter time history records, analysis of ground vehicle friction measurements and harmonization with aircraft braking performance, assessment of induced aircraft contaminant drag, and evaluation of the effects of other factors on aircraft/ground vehicle friction performance will be documented in a NASA Technical Report which is being prepared for publication next year.

  12. Buffet induced structural/flight-control system interaction of the X-29A aircraft

    NASA Technical Reports Server (NTRS)

    Voracek, David F.; Clarke, Robert

    1991-01-01

    High-alpha flight creates unique aerodynamic phenomena which increase the level of structural mode excitation; in conjunction with high-gain digital control systems, this structural response may result in an aeroservoelastic interaction. One such interaction has been observed during high-alpha flight testing of the X-29A. Data are presented which demonstrate the enhanced modal power in this aircraft's structural accelerometers, the feedback sensors, and the command signals as a function of alpha value. The structural interaction is traced from the aerodynamic buffet to the flight-control surfaces.

  13. A new role for structures technology in aircraft configuration development

    NASA Technical Reports Server (NTRS)

    Nisbet, J. W.; Hoy, J. M.

    1976-01-01

    It is pointed out that decisions made during configuration development determine nearly 60% of the total program cost. The key to the new Structures Technology role considered is the development of integrated computer systems for structural design and analysis. Such systems make it possible to include structural sizing within the scope of preliminary configuration development. Analysis models are discussed, taking into account approaches used to determine the structural weight of an aircraft in the preliminary design stage, a finite element representation for a supersonic arrow wing transport, and the aerodynamic model. Attention is given to automated design considerations and a study which was conducted to reduce the aerodynamic drag of a supersonic transport by blending the structure of the wing and fuselage.

  14. Forced Oscillation Wind Tunnel Testing for FASER Flight Research Aircraft

    NASA Technical Reports Server (NTRS)

    Hoe, Garrison; Owens, Donald B.; Denham, Casey

    2012-01-01

    As unmanned air vehicles (UAVs) continue to expand their flight envelopes into areas of high angular rate and high angle of attack, modeling the complex unsteady aerodynamics for simulation in these regimes has become more difficult using traditional methods. The goal of this experiment was to improve the current six degree-of-freedom aerodynamic model of a small UAV by replacing the analytically derived damping derivatives with experimentally derived values. The UAV is named the Free-flying Aircraft for Sub-scale Experimental Research, FASER, and was tested in the NASA Langley Research Center 12- Foot Low-Speed Tunnel. The forced oscillation wind tunnel test technique was used to measure damping in the roll and yaw axes. By imparting a variety of sinusoidal motions, the effects of non-dimensional angular rate and reduced frequency were examined over a large range of angle of attack and side-slip combinations. Tests were performed at angles of attack from -5 to 40 degrees, sideslip angles of -30 to 30 degrees, oscillation amplitudes from 5 to 30 degrees, and reduced frequencies from 0.010 to 0.133. Additionally, the effect of aileron or elevator deflection on the damping coefficients was examined. Comparisons are made of two different data reduction methods used to obtain the damping derivatives. The results show that the damping derivatives are mainly a function of angle of attack and have dependence on the non-dimensional rate and reduced frequency only in the stall/post-stall regime

  15. Evaluation of bonded boron/epoxy doublers for commercial aircraft aluminum structures

    NASA Technical Reports Server (NTRS)

    Belason, Bruce; Rutherford, Paul; Miller, Matthew; Raj, Shreeram

    1994-01-01

    An 18 month laboratory test and stress analysis program was conducted to evaluate bonded boron/epoxy doublers for repairing cracks on aluminum aircraft structures. The objective was to obtain a core body of substantiating data which will support approval for use on commercial transports of a technology that is being widely used by the military. The data showed that the doublers had excellent performance.

  16. Comparison of Requirements for Composite Structures for Aircraft and Space Applications

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Elliott, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

    2010-01-01

    In this paper, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry, and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

  17. SR-71A in Flight with Test Fixture Mounted Atop the Aft Section of the Aircraft

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This close-up, head-on view of NASA's SR-71A Blackbird in flight shows the aircraft with an experimental test fixture mounted on the back of the airplane. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet video camera

  18. PASS: A computer program for Preliminary Aircraft Structural Synthesis

    NASA Technical Reports Server (NTRS)

    Johnson, E. H.

    1977-01-01

    A computer code for Preliminary Aircraft Structural Synthesis provides rapid and accurate analysis for aircraft structures that can be adequately modeled by beam finite elements. The philosophy used in developing the program was to provide a basic framework that can be used for structural synthesis. It is anticipated that a user will need to add detail to this framework in order to perform his specific task. With this philosophy in mind, the program was written so that it is easily divided into segments, thereby making it readily adaptable. The theoretical portion of this manual describes the basic structure of the program and details the development of the unique beam element that is used. The present capability of the algorithm is stated and suggestions are made regarding enhancements to this capability. User information is also given that provides an overview of the program's construction, identifies the required inputs, describes the program output, provides some comments on the program use, and exhibits results for a simple example.

  19. Equivalent plate modeling for conceptual design of aircraft wing structures

    NASA Technical Reports Server (NTRS)

    Giles, Gary L.

    1995-01-01

    This paper describes an analysis method that generates conceptual-level design data for aircraft wing structures. A key requirement is that this data must be produced in a timely manner so that is can be used effectively by multidisciplinary synthesis codes for performing systems studies. Such a capability is being developed by enhancing an equivalent plate structural analysis computer code to provide a more comprehensive, robust and user-friendly analysis tool. The paper focuses on recent enhancements to the Equivalent Laminated Plate Solution (ELAPS) analysis code that significantly expands the modeling capability and improves the accuracy of results. Modeling additions include use of out-of-plane plate segments for representing winglets and advanced wing concepts such as C-wings along with a new capability for modeling the internal rib and spar structure. The accuracy of calculated results is improved by including transverse shear effects in the formulation and by using multiple sets of assumed displacement functions in the analysis. Typical results are presented to demonstrate these new features. Example configurations include a C-wing transport aircraft, a representative fighter wing and a blended-wing-body transport. These applications are intended to demonstrate and quantify the benefits of using equivalent plate modeling of wing structures during conceptual design.

  20. Resin transfer molding of textile preforms for aircraft structural applications

    NASA Technical Reports Server (NTRS)

    Hasko, Gregory H.; Dexter, H. Benson; Weideman, Mark H.

    1992-01-01

    The NASA LaRC is conducting and supporting research to develop cost-effective fabrication methods that are applicable to primary composite aircraft structures. One of the most promising fabrication methods that has evolved is resin transfer molding (RTM) of dry textile material forms. RTM has been used for many years for secondary structures, but has received increased emphasis because it is an excellent method for applying resin to damage-tolerant textile preforms at low cost. Textile preforms based on processes such as weaving, braiding, knitting, stitching, and combinations of these have been shown to offer significant improvements in damage tolerance compared to laminated tape composites. The use of low-cost resins combined with textile preforms could provide a major breakthrough in achieving cost-effective composite aircraft structures. RTM uses resin in its lowest cost form, and storage and spoilage costs are minimal. Near net shape textile preforms are expected to be cost-effective because automated machines can be used to produce the preforms, post-cure operations such as machining and fastening are minimized, and material scrap rate may be reduced in comparison with traditional prepreg molding. The purpose of this paper is to discuss experimental and analytical techniques that are under development at NASA Langley to aid the engineer in developing RTM processes for airframe structural elements. Included are experimental techniques to characterize preform and resin behavior and analytical methods that were developed to predict resin flow and cure kinetics.

  1. Design, Fabrication, and Testing of Composite Energy-Absorbing Keel Beams for General Aviation Type Aircraft

    NASA Technical Reports Server (NTRS)

    Kellas, Sotiris; Knight, Norman F., Jr.

    2002-01-01

    A lightweight energy-absorbing keel-beam concept was developed and retrofitted in a general aviation type aircraft to improve crashworthiness performance. The energy-absorbing beam consisted of a foam-filled cellular structure with glass fiber and hybrid glass/kevlar cell walls. Design, analysis, fabrication and testing of the keel beams prior to installation and subsequent full-scale crash testing of the aircraft are described. Factors such as material and fabrication constraints, damage tolerance, crush stress/strain response, seat-rail loading, and post crush integrity, which influenced the course of the design process are also presented. A theory similar to the one often used for ductile metal box structures was employed with appropriate modifications to estimate the sustained crush loads for the beams. This, analytical tool, coupled with dynamic finite element simulation using MSC.Dytran were the prime design and analysis tools. The validity of the theory as a reliable design tool was examined against test data from static crush tests of beam sections while the overall performance of the energy-absorbing subfloor was assessed through dynamic testing of 24 in long subfloor assemblies.

  2. Analysis and testing of stability augmentation systems. [for supersonic transport aircraft wing and B-52 aircraft control system

    NASA Technical Reports Server (NTRS)

    Sevart, F. D.; Patel, S. M.; Wattman, W. J.

    1972-01-01

    Testing and evaluation of stability augmentation systems for aircraft flight control were conducted. The flutter suppression system analysis of a scale supersonic transport wing model is described. Mechanization of the flutter suppression system is reported. The ride control synthesis for the B-52 aeroelastic model is discussed. Model analyses were conducted using equations of motion generated from generalized mass and stiffness data.

  3. Smart aircraft composite structures with embedded small-diameter optical fiber sensors

    NASA Astrophysics Data System (ADS)

    Takeda, Nobuo; Minakuchi, Shu

    2012-02-01

    This talk describes the embedded optical fiber sensor systems for smart aircraft composite structures. First, a summary of the current Japanese national project on structural integrity diagnosis of aircraft composite structures is described with special emphasis on the use of embedded small-diameter optical fiber sensors including FBG sensors. Then, some examples of life-cycle monitoring of aircraft composite structures are presented using embedded small-diameter optical fiber sensors for low-cost and reliable manufacturing merits.

  4. Buffet induced structural/flight-control system interaction of the X-29A aircraft

    NASA Technical Reports Server (NTRS)

    Voracek, David F.; Clarke, Robert

    1991-01-01

    High angle-of-attack flight regime research is currently being conducted for modern fighter aircraft at the NASA Ames Research Center's Dryden Flight Research Facility. This flight regime provides enhanced maneuverability to fighter pilots in combat situations. Flight research data are being acquired to compare and validate advanced computational fluid dynamic solutions and wind-tunnel models. High angle-of-attack flight creates unique aerodynamic phenomena including wing rock and buffet on the airframe. These phenomena increase the level of excitation of the structural modes, especially on the vertical and horizontal stabilizers. With high gain digital flight-control systems, this structural response may result in an aeroservoelastic interaction. A structural interaction on the X-29A aircraft was observed during high angle-of-attack flight testing. The roll and yaw rate gyros sensed the aircraft's structural modes at 11, 13, and 16 Hz. The rate gyro output signals were then amplified through the flight-control laws and sent as commands to the flaperons and rudder. The flight data indicated that as the angle of attack increased, the amplitude of the buffet on the vertical stabilizer increased, which resulted in more excitation to the structural modes. The flight-control system sensors and command signals showed this increase in modal power at the structural frequencies up to a 30 degree angle-of-attack. Beyond a 30 degree angle-of-attack, the vertical stabilizer response, the feedback sensor amplitude, and control surface command signal amplitude remained relatively constant. Data are presented that show the increased modal power in the aircraft structural accelerometers, the feedback sensors, and the command signals as a function of angle of attack. This structural interaction is traced from the aerodynamic buffet to the flight-control surfaces.

  5. Advances in experimental mechanics for advanced aircraft structures

    NASA Astrophysics Data System (ADS)

    O'Brien, Eddie W.

    1997-03-01

    The industrial requirement for higher efficiency, lean performance, airframe structures to form the basis of more cost effective Commercial Aircraft has encouraged developments in all aspects of aeronautical design and manufacture. Until recently the main emphasis has been in the area of computer and numerical analysis, however new developments in experimental mechanics are emerging as very powerful tools for use in the validation of numerical analyses and for primary stress analysis data. The developments described have been forced by economic drivers that address more efficient analysis techniques with respect to cost, specific weight and expended time for analysis.

  6. Laser Welding of Large Scale Stainless Steel Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Reitemeyer, D.; Schultz, V.; Syassen, F.; Seefeld, T.; Vollertsen, F.

    In this paper a welding process for large scale stainless steel structures is presented. The process was developed according to the requirements of an aircraft application. Therefore, stringers are welded on a skin sheet in a t-joint configuration. The 0.6 mm thickness parts are welded with a thin disc laser, seam length up to 1920 mm are demonstrated. The welding process causes angular distortions of the skin sheet which are compensated by a subsequent laser straightening process. Based on a model straightening process parameters matching the induced welding distortion are predicted. The process combination is successfully applied to stringer stiffened specimens.

  7. RSRA vertical drag test report. [rotor systems research aircraft

    NASA Technical Reports Server (NTRS)

    Flemming, R. J.

    1981-01-01

    The Rotor Systems Research Aircraft (RSRA), because of its ability to measure rotor loads, was used to conduct an experiment to determine vertical drag, tail rotor blockage, and thrust augmentation as affected by ground clearance and flight velocity. The RSRA was flown in the helicopter configuration at speeds from 0 to 15 knots for wheel heights from 5 to 150 feet, and to 60 knots out of ground effect. The vertical drag trends in hover, predicted by theory and shown in model tests, were generally confirmed. The OGE hover vertical drag is 4.0 percent, 1.1 percent greater than predicted. The vertical drag decreases rapidly as wheel height is reduced, and is zero at a wheel height of 6 feet. The vertical drag also decreases with forward speed, approaching zero at sixty knots. The test data show the effect of wheel height and forward speed on thrust, gross weight capability, and power, and provide the relationships for power and collective pitch at constant gross weight required for the simulation of helicopter takeoffs and landings.

  8. Development and testing of improved polyimide actuator rod seals at higher temperatures for use in advanced aircraft hydraulic systems

    NASA Technical Reports Server (NTRS)

    Robinson, E. D.; Waterman, A. W.; Nelson, W. G.

    1972-01-01

    Polyimide second stage rod seals were evaluated to determine their suitability for application in advanced aircraft systems. The configurations of the seals are described. The conditions of the life cycle tests are provided. It was determined that external rod seal leakage was within prescribed limits and that the seals showed no signs of structural degradation.

  9. Damage criticality and inspection concerns of composite-metallic aircraft structures under blunt impact

    NASA Astrophysics Data System (ADS)

    Zou, D.; Haack, C.; Bishop, P.; Bezabeh, A.

    2015-04-01

    Composite aircraft structures such as fuselage and wings are subject to impact from many sources. Ground service equipment (GSE) vehicles are regarded as realistic sources of blunt impact damage, where the protective soft rubber is used. With the use of composite materials, blunt impact damage is of special interest, since potential significant structural damage may be barely visible or invisible on the structure's outer surface. Such impact can result in local or non-local damage, in terms of internal delamination in skin, interfacial delamination between stiffeners and skin, and fracture of internal reinforced component such as stringers and frames. The consequences of these events result in aircraft damage, delays, and financial cost to the industry. Therefore, it is necessary to understand the criticality of damage under this impact and provide reliable recommendations for safety and inspection technologies. This investigation concerns a composite-metallic 4-hat-stiffened and 5-frame panel, designed to represent a fuselage structure panel generic to the new generation of composite aircraft. The test fixtures were developed based on the correlation between finite element analyses of the panel model and the barrel model. Three static tests at certain amount of impact energy were performed, in order to improve the understanding of the influence of the variation in shear ties, and the added rotational stiffness. The results of this research demonstrated low velocity high mass impacts on composite aircraft fuselages beyond 82.1 kN of impact load, which may cause extensive internal structural damage without clear visual detectability on the external skin surface.

  10. Laboratory test and acoustic analysis of cabin treatment for propfan test assessment aircraft

    NASA Technical Reports Server (NTRS)

    Kuntz, H. L.; Gatineau, R. J.

    1991-01-01

    An aircraft cabin acoustic enclosure, built in support of the Propfan Test Assessment (PTA) program, is described. Helmholtz resonators were attached to the cabin trim panels to increase the sidewall transmission loss (TL). Resonators (448) were located between the trim panels and fuselage shell. In addition, 152 resonators were placed between the enclosure and aircraft floors. The 600 resonators were each tuned to a 235 Hz resonance frequency. After flight testing on the PTA aircraft, the enclosure was tested in the Kelly Johnson R and D Center Acoustics Lab. Laboratory noise reduction (NR) test results are discussed. The enclosure was placed in a Gulfstream 2 fuselage section. Broadband (138 dB overall SPL) and tonal (149 dB overall SPL) excitations were used in the lab. Tonal excitation simulated the propfan flight test excitation. The fundamental tone was stepped in 2 Hz intervals from 225 through 245 Hz. The resonators increase the NR of the cabin walls around the resonance frequency of the resonator array. The effects of flanking, sidewall absorption, cabin adsorption, resonator loading of trim panels, and panel vibrations are presented. Increases in NR of up to 11 dB were measured.

  11. Durability of commercial aircraft and helicopter composite structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1982-01-01

    The development of advanced composite technology during the past decade is discussed. Both secondary and primary components fabricated with boron, graphite, and Kevlar composites are evaluated. Included are spoilers, rudders, and fairings on commercial transports, boron/epoxy reinforced wing structure on C-130 military transports, and doors, fairings, tail rotors, vertical fins, and horizontal stabilizers on commercial helicopters. The development of composite structures resulted in advances in design and manufacturing technology for secondary and primary composite structures for commercial transports. Design concepts and inspection and maintenance results for the components in service are reported. The flight, outdoor ground, and controlled laboratory environmental effects on composites were also determined. Effects of moisture absorption, ultraviolet radiation, aircraft fuels and fluids, and sustained tensile stress are included. Critical parameters affecting the long term durability of composite materials are identified.

  12. Sonic environment of aircraft structure immersed in a supersonic jet flow stream

    NASA Technical Reports Server (NTRS)

    Guinn, W. A.; Balena, F. J.; Soovere, J.

    1976-01-01

    Test methods for determining the sonic environment of aircraft structure that is immersed in the flow stream of a high velocity jet or that is subjected to the noise field surrounding the jet, were investigated. Sonic environment test data measured on a SCAT 15-F model in the flow field of Mach 1.5 and 2.5 jets were processed. Narrow band, lateral cross correlation and noise contour plots are presented. Data acquisition and reduction methods are depicted. A computer program for scaling the model data is given that accounts for model size, jet velocity, transducer size, and jet density. Comparisons of scaled model data and full size aircraft data are made for the L-1011, S-3A, and a V/STOL lower surface blowing concept. Sonic environment predictions are made for an engine-over-the-wing SST configuration.

  13. Deflection-Based Aircraft Structural Loads Estimation with Comparison to Flight

    NASA Technical Reports Server (NTRS)

    Lizotte, Andrew M.; Lokos, William A.

    2005-01-01

    Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. With a reliable strain and structural deformation measurement system this technique was examined. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.

  14. Deflection-Based Structural Loads Estimation From the Active Aeroelastic Wing F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lizotte, Andrew M.; Lokos, William A.

    2005-01-01

    Traditional techniques in structural load measurement entail the correlation of a known load with strain-gage output from the individual components of a structure or machine. The use of strain gages has proved successful and is considered the standard approach for load measurement. However, remotely measuring aerodynamic loads using deflection measurement systems to determine aeroelastic deformation as a substitute to strain gages may yield lower testing costs while improving aircraft performance through reduced instrumentation weight. This technique was examined using a reliable strain and structural deformation measurement system. The objective of this study was to explore the utility of a deflection-based load estimation, using the active aeroelastic wing F/A-18 aircraft. Calibration data from ground tests performed on the aircraft were used to derive left wing-root and wing-fold bending-moment and torque load equations based on strain gages, however, for this study, point deflections were used to derive deflection-based load equations. Comparisons between the strain-gage and deflection-based methods are presented. Flight data from the phase-1 active aeroelastic wing flight program were used to validate the deflection-based load estimation method. Flight validation revealed a strong bending-moment correlation and slightly weaker torque correlation. Development of current techniques, and future studies are discussed.

  15. Comparison of structural response and fatigue endurance of aircraft flap-like box structures subjected to acoustic loading.

    PubMed

    Xiao, Y; White, R G; Aglietti, G S

    2005-05-01

    The results of an extensive test program to characterize the behavior of typical aircraft structures under acoustic loading and to establish their fatigue endurance are presented. The structures tested were the three flap-like box-type of structures. Each structure consisted of one flat (bottom) and one curved (top) stiffener stiffened skin panel, front, and rear spars, and ribs that divided the structures into three bays. The three structures, constructed from three different materials (aircraft standard aluminum alloy, Carbon Fibre Reinforced Plastic, and a Glass Fibre Metal Laminate, i.e., GLARE) had the same size and configuration, with only minor differences due to the use of different materials. A first set of acoustic tests with excitations of intensity ranging from 140 to 160 dB were carried out to obtain detailed data on the dynamic response of the three structures. The FE analysis of the structures is also briefly described and the results compared with the experimental data. The fatigue endurance of the structures was then determined using random acoustic excitation with an overall sound pressure level of 161 dB, and details of crack propagation are reported. PMID:15957753

  16. Recent NASA progress in composites. [application to spacecraft and aircraft structures

    NASA Technical Reports Server (NTRS)

    Heldenfels, R. R.

    1975-01-01

    The application of composites in aerospace vehicle structures is reviewed. Research and technology program results and specific applications to space vehicles, aircraft engines, and aircraft and helicopter structures are discussed in detail. Particular emphasis is given to flight service evaluation programs that are or will be accumulating substantial experience with secondary and primary structural components on military and commercial aircraft to increase confidence in their use.

  17. Design-Oriented Analysis of Aircraft Fuselage Structures

    NASA Technical Reports Server (NTRS)

    Giles, Gary L.

    1998-01-01

    A design-oriented analysis capability for aircraft fuselage structures that utilizes equivalent plate methodology is described. This new capability is implemented as an addition to the existing wing analysis procedure in the Equivalent Laminated Plate Solution (ELAPS) computer code. The wing and fuselage analyses are combined to model entire airframes. The paper focuses on the fuselage model definition, the associated analytical formulation and the approach used to couple the wing and fuselage analyses. The modeling approach used to minimize the amount of preparation of input data by the user and to facilitate the making of design changes is described. The fuselage analysis is based on ring and shell equations but the procedure is formulated to be analogous to that used for plates in order to take advantage of the existing code in ELAPS. Connector springs are used to couple the wing and fuselage models. Typical fuselage analysis results are presented for two analytical models. Results for a ring-stiffened cylinder model are compared with results from conventional finite-element analyses to assess the accuracy of this new analysis capability. The connection of plate and ring segments is demonstrated using a second model that is representative of the wing structure for a channel-wing aircraft configuration.

  18. Dynamic ground effects flight test of an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Corda, Stephen; Stephenson, Mark T.; Burcham, Frank W.; Curry, Robert E.

    1994-01-01

    Flight tests to determine the changes in the aerodynamic characteristics of an F-15 aircraft caused by dynamic ground effects are described. Data were obtained for low and high sink rates between 0.7 and 6.5 ft/sec and at two landing approach speeds and flap settings: 150 kn with the flaps down and 170 kn with the flaps up. Simple correlation curves are given for the change in aerodynamic coefficients because of ground effects as a function of sink rate. Ground effects generally caused an increase in the lift, drag, and nose-down pitching movement coefficients. The change in the lift coefficient increased from approximately 0.05 at the high-sink rate to approximately 0.10 at the low-sink rate. The change in the drag coefficient increased from approximately 0 to 0.03 over this decreasing sink rate range. No significant difference because of the approach configuration was evident for lift and drag; however, a significant difference in pitching movement was observed for the two approach speeds and flap settings. For the 170 kn with the flaps up configuration, the change in the nose-down pitching movement increased from approximately -0.008 to -0.016. For the 150 kn with the flaps down configuration, the change was approximately -0.008 to -0.038.

  19. Strain Gage Loads Calibration Testing with Airbag Support for the Gulfstream III SubsoniC Research Aircraft Testbed (SCRAT)

    NASA Technical Reports Server (NTRS)

    Lokos, William; Miller, Eric; Hudson, Larry; Holguin, Andrew; Neufeld, David; Haraguchi, Ronnie

    2015-01-01

    This paper describes the design and conduct of the strain gage load calibration ground test of the SubsoniC Research Aircraft Testbed, Gulfstream III aircraft, and the subsequent data analysis and its results. The goal of this effort was to create and validate multi-gage load equations for shear force, bending moment, and torque for two wing measurement stations. For some of the testing the aircraft was supported by three air bags in order to isolate the wing structure from extraneous load inputs through the main landing gear. Thirty-two strain gage bridges were installed on the left wing. Hydraulic loads were applied to the wing lower surface through a total of 16 load zones. Some dead weight load cases were applied to the upper wing surface using shot bags. Maximum applied loads reached 54,000 pounds.

  20. Strain Gage Loads Calibration Testing with Airbag Support for the Gulfstream III SubsoniC Research Aircraft Testbed (SCRAT)

    NASA Technical Reports Server (NTRS)

    Lokos, William A.; Miller, Eric J.; Hudson, Larry D.; Holguin, Andrew C.; Neufeld, David C.; Haraguchi, Ronnie

    2015-01-01

    This paper describes the design and conduct of the strain-gage load calibration ground test of the SubsoniC Research Aircraft Testbed, Gulfstream III aircraft, and the subsequent data analysis and results. The goal of this effort was to create and validate multi-gage load equations for shear force, bending moment, and torque for two wing measurement stations. For some of the testing the aircraft was supported by three airbags in order to isolate the wing structure from extraneous load inputs through the main landing gear. Thirty-two strain gage bridges were installed on the left wing. Hydraulic loads were applied to the wing lower surface through a total of 16 load zones. Some dead-weight load cases were applied to the upper wing surface using shot bags. Maximum applied loads reached 54,000 lb. Twenty-six load cases were applied with the aircraft resting on its landing gear, and 16 load cases were performed with the aircraft supported by the nose gear and three airbags around the center of gravity. Maximum wing tip deflection reached 17 inches. An assortment of 2, 3, 4, and 5 strain-gage load equations were derived and evaluated against independent check cases. The better load equations had root mean square errors less than 1 percent. Test techniques and lessons learned are discussed.

  1. Highly Maneuverable Aircraft Technology (HiMAT) flight-flutter test program

    NASA Technical Reports Server (NTRS)

    Kehoe, M. W.

    1984-01-01

    The highly maneuverable aircraft technology (HiMAT) vehicle was evaluated in a joint NASA and Air Force flight test program. The HiMAT vehicle is a remotely piloted research vehicle. Its design incorporates the use of advanced composite materials in the wings, and canards for aeroelastic tailoring. A flight-flutter test program was conducted to clear a sufficient flight envelope to allow for performance, stability and control, and loads testing. Testing was accomplished with and without flight control-surface dampers. Flutter clearance of the vehicle indicated satisfactory damping and damping trends for the structural modes of the HiMAT vehicle. The data presented include frequency and damping plotted as a function of Mach number.

  2. Testing of aircraft passenger seat cushion materials. Full scale, test description and results, volume 1

    NASA Technical Reports Server (NTRS)

    Schutter, K. J.; Gaume, J. G.; Duskin, F. E.

    1981-01-01

    Eight different seat cushion configurations were subjected to full-scale burn tests. Each cushion configuration was tested twice for a total of sixteen tests. Two different fire sources were used. They consisted of one liter of Jet A fuel for eight tests and a radiant energy source with propane flame for eight tests. Both fire sources were ignited by a propane flame. During each test, data were recorded for smoke density, cushion temperatures, radiant heat flux, animal response to combustion products, rate of weight loss of test specimens, cabin temperature, and for the type and content of gas within the cabin atmosphere. When compared to existing passenger aircraft seat cushions, the test specimens incorporating a fire barrier and those fabricated from advanced materials, using improved construction methods, exhibited significantly greater fire resistance.

  3. A fuselage/tank structure study for actively cooled hypersonic cruise vehicles: Aircraft design evaluation

    NASA Technical Reports Server (NTRS)

    Nobe, T.

    1975-01-01

    The effects of fuselage cross sections and structural members on the performance of hypersonic cruise aircraft are evaluated. Representative fuselage/tank area structure was analyzed for strength, stability, fatigue and fracture mechanics. Various thermodynamic and structural tradeoffs were conducted to refine the conceptual designs with the primary objective of minimizing weight and maximizing aircraft range.

  4. Flow-Field Survey in the Test Region of the SR-71 Aircraft Test Bed Configuration

    NASA Technical Reports Server (NTRS)

    Mizukami, Masashi; Jones, Daniel; Weinstock, Vladimir D.

    2000-01-01

    A flat plate and faired pod have been mounted on a NASA SR-71A aircraft for use as a supersonic flight experiment test bed. A test article can be placed on the flat plate; the pod can contain supporting systems. A series of test flights has been conducted to validate this test bed configuration. Flight speeds to a maximum of Mach 3.0 have been attained. Steady-state sideslip maneuvers to a maximum of 2 deg have been conducted, and the flow field in the test region has been surveyed. Two total-pressure rakes, each with two flow-angle probes, have been placed in the expected vicinity of an experiment. Static-pressure measurements have been made on the flat plate. At subsonic and low supersonic speeds with no sideslip, the flow in the surveyed region is quite uniform. During sideslip maneuvers, localized flow distortions impinge on the test region. Aircraft sideslip does not produce a uniform sidewash over the test region. At speeds faster than Mach 1.5, variable-pressure distortions were observed in the test region. Boundary-layer thickness on the flat plate at the rake was less than 2.1 in. For future experiments, a more focused and detailed flow-field survey than this one would be desirable.

  5. NACA Conference on Aircraft Loads, Structures, and Flutter

    NASA Technical Reports Server (NTRS)

    1957-01-01

    This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results. The papers in this document are in the same form in which they were presented at the Conference in order to facilitate their prompt distribution. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee?s more complete and formal reports. Accordingly, if information from this document is utilized it is requested that this document not be listed as a reference. Individual reports dealing with most of the information presented at the Conference will subsequently be published by NACA and will therefore be suitable as reference material.

  6. Mobile HTS SQUID System for Nondestructive Evaluation of Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Krause, Hans-Joachim; Hohmann, Rainer; Grueneklee, Michael; Zhang, Yi; Braginski, Alex I.

    1997-03-01

    For the detection of deep-lying flaws in aircraft structures, a mobile eddy-current system is being developed in conjunction with a high-temperature superconductor (Yba_2Cu_3O_7) thin-film HTS SQUID gradiometer. The challenge is to operate the SQUID sensor during movement in strong ambient fields, independent of orientation. A planar rf double hole gradiometer with a gradient sensitivity of 500 fT/(cm √Hz) was designed for that purpose. Two different cooling concepts were successfully implemented: the SQUID operation in the vacuum region of a lightweight nitrogen cryostat, constructed for operation in any orientation, and the use of a commercial Joule-Thomson cryocooler for liquid-nitrogen-free SQUID cooling. With a SQUID integration scheme using a sapphire cold finger, motion-related additional noise is nearly eliminated. Using a system equipped with a differential eddy current excitation, two-dimensional scans were performed to find fatigue cracks and corrosion pits hidden below several layers of aluminum. For demonstration in the Lufthansa maintenance facility at Frankfurt Airport, the system was used to detect flaws in aircraft wheels. Work in progress includes developing longer base gradiometers for detection of deep flaws.

  7. Smart structural fasteners for the aircraft and construction industries

    NASA Astrophysics Data System (ADS)

    Thompson, Larry D.; Westermo, Bruce D.; Crum, Duane B.; Law, Will; Trombi, Robert; Waldbusser, Raymond

    1999-06-01

    This paper discusses research and development efforts directed at producing a passive, smart bolt for infrastructure applications. The smart bolts are fabricated from high-strength TRIP (Transformation Induced Plasticity) Steels. TRIP steels gradually transform from a non-magnetic, austenitic parent phase to a ferromagnetic, martensitic product phase. The stress-assisted (elastic range) and strain-induced (plastic range) phase transitions that inherently occur in the material provide a magnetic signature by which the damage state of the bolt can be determined. The irreversible nature of the phase transformations means that the bolt can passively retain peak strain (i.e., peak damage information) for later interrogation. Several different smart bolt design concepts were considered and evaluated. Design modeling and smart bolt optimization were achieved with the aid of a series of Pro/Engineer solid model renderings and a Pro/Mechanica finite element model analysis. The smart bolt was developed for high-tension fastener applications in the USAF C-130 Hercules cargo aircraft. Alloy design efforts, testing, and evaluation data are presented and discussed. Full-scale, smart aircraft bolt manufacturing is discussed and field application scheduling/evaluation plans are outlined. Extension of the smart bolt technology for construction industry applications is discussed.

  8. Missile airframe simulation testbed: MANPADS (MAST-M) for test and evaluation of aircraft survivability equipment

    NASA Astrophysics Data System (ADS)

    Clements, Jim; Robinson, Richard; Bunt, Leslie; Robinson, Joe

    2011-06-01

    A number of techniques have been utilized to evaluate the performance of Aircraft Survivability Equipment (ASE) against threat Man-Portable Air Defense Systems (MANPADS). These techniques include flying actual threat MANPADS against stationary ASE with simulated aircraft signatures, testing installed ASE systems against simulated threat signatures, and laboratory hardware-in-the-loop (HWIL) testing with simulated aircraft and simulated missile signatures. All of these tests lack the realism of evaluating installed ASE against in-flight MANPADS on a terminal homing intercept path toward the actual ASE equipped aircraft. This limitation is due primarily to the current inability to perform non-destructive MANPADS/Aircraft flight testing. The U.S. Army Aviation and Missile Research and Development and Engineering Center (AMRDEC) is working to overcome this limitation with the development of a recoverable surrogate MANPADS missile system capable of engaging aircraft equipped with ASE while guaranteeing collision avoidance with the test aircraft. Under its Missile Airframe Simulation Testbed - MANPADS (MAST-M) program, the AMRDEC is developing a surrogate missile system which will utilize actual threat MANPADS seeker/guidance sections to control the flight of a surrogate missile which will perform a collision avoidance and recovery maneuver prior to intercept to insure non-destructive test and evaluation of the ASE and reuse of the MANPADS seeker/guidance section. The remainder of this paper provides an overview of this development program and intended use.

  9. Data acquisition/reduction system for flight testing general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Rummer, D. I.; Mosser, M. A.; Renz, R. R. L.

    1982-01-01

    The development of a data acquisition/reduction system for use in the flight testing of general aviation aircraft is described. Design objectives for the system are adequate accuracy, ease of installation and removal from aircraft, simplicity of operation, and low cost. A 16-channel working system has been constructed, and tested in the collection of flight test data from a Cessna 172 aircraft, which uses as the basis of its design an AIM65 microcomputer. Data is reduced with a MINC minicomputer system. Attention is given to the onboard installation of computer, battery and transducer modules incorporated by the system.

  10. Reproducibility of structural strength and stiffness for graphite-epoxy aircraft spoilers

    NASA Technical Reports Server (NTRS)

    Howell, W. E.; Reese, C. D.

    1978-01-01

    Structural strength reproducibility of graphite epoxy composite spoilers for the Boeing 737 aircraft was evaluated by statically loading fifteen spoilers to failure at conditions simulating aerodynamic loads. Spoiler strength and stiffness data were statistically modeled using a two parameter Weibull distribution function. Shape parameter values calculated for the composite spoiler strength and stiffness were within the range of corresponding shape parameter values calculated for material property data of composite laminates. This agreement showed that reproducibility of full scale component structural properties was within the reproducibility range of data from material property tests.

  11. On-Line Mu Method for Robust Flutter Prediction in Expanding a Safe Flight Envelope for an Aircraft Model Under Flight Test

    NASA Technical Reports Server (NTRS)

    Lind, Richard C. (Inventor); Brenner, Martin J.

    2001-01-01

    A structured singular value (mu) analysis method of computing flutter margins has robust stability of a linear aeroelastic model with uncertainty operators (Delta). Flight data is used to update the uncertainty operators to accurately account for errors in the computed model and the observed range of aircraft dynamics of the aircraft under test caused by time-varying aircraft parameters, nonlinearities, and flight anomalies, such as test nonrepeatability. This mu-based approach computes predict flutter margins that are worst case with respect to the modeling uncertainty for use in determining when the aircraft is approaching a flutter condition and defining an expanded safe flight envelope for the aircraft that is accepted with more confidence than traditional methods that do not update the analysis algorithm with flight data by introducing mu as a flutter margin parameter that presents several advantages over tracking damping trends as a measure of a tendency to instability from available flight data.

  12. Aircraft structural health monitoring system development: overview of the Air Force/Navy smart metallic structures program

    NASA Astrophysics Data System (ADS)

    Van Way, Craig B.; Kudva, Jayanth N.; Schoess, Jeffrey N.; Zeigler, Michael L.; Alper, James M.

    1995-05-01

    Significant progress in fulfilling the current joint Air Force/Navy `Smart Metallic Structures (SMS)' program primary objective, to demonstrate a viable structural health monitoring system (SHMS) for a large structural aircraft component, is presented. Structural health monitoring and its relation to current Force Management (FM) and Aircraft Structural Integrity Program (ASIP) procedures are first reviewed together with a brief status overview of the relevant sensor technologies (e.g. AE, fiber-optic, corrosion, etc.). Key features of the SHMS architecture are described for the selected F/A-18 bulkhead and T-38 wing spar structural demonstration articles, highlighting sensors, processors, data busses, hardware, and software. Results from acoustic monitoring of the program sub-element structural tests are presented in some detail along with a status review of the SHMS multiplex bus component hardware and software. Finally, structural requirements for an SHMS meeting minimum ASIP guidelines for damage detection are discussed along with foals for future testing and development of the SHMS under the SMS program.

  13. Damage detection in aircraft structures using dynamically measured static flexibility matrices

    SciTech Connect

    Robinson, N.A.; Peterson, L.D.; James, G.H.; Doebling, S.W.

    1996-02-01

    Two methods for detecting the location of structural damage in an aircraft fuselage using modal test data are presented. Both methods use the dynamically measured static flexibility matrix, which is assembled from a combination of measured modal vectors, frequencies, and driving point residual flexibilities. As a consequence, neither method requires a mode-to-mode correlation, and both avoid tedious modal discrimination and selection. The first method detects damage as a softening in the point flexibility components, which are the diagonal entries in the flexibility matrix. The second method detects damage from the disassembled elemental stiffnesses as determined using a presumed connectivity. Vibration data from a laser vibrometer is used to measure the modal mechanics of a DC9 aircraft fuselage before and after induced weakening in a longitudinal stringer. Both methods are shown to detect the location of the damage, primarily because the normal stiffness of the reinforced shell of the fuselage is localized to a few square centimeters.

  14. Follow on Research for Multi-Utility Technology Test Bed Aircraft at NASA Dryden Flight Research Center (FY13 Progress Report)

    NASA Technical Reports Server (NTRS)

    Pak, Chan-Gi

    2013-01-01

    Modern aircraft employ a significant fraction of their weight in composite materials to reduce weight and improve performance. Aircraft aeroservoelastic models are typically characterized by significant levels of model parameter uncertainty due to the composite manufacturing process. Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of Multi Utility Technology Test-bed (MUTT) aircraft is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of MUTT aircraft. The ground vibration test-validated structural dynamic finite element model of the MUTT aircraft is created in this study. The structural dynamic finite element model of MUTT aircraft is improved using the in-house Multi-disciplinary Design, Analysis, and Optimization tool. In this study, two different weight configurations of MUTT aircraft have been improved simultaneously in a single model tuning procedure.

  15. A Study of Vehicle Structural Layouts in Post-WWII Aircraft

    NASA Technical Reports Server (NTRS)

    Sensmeier, Mark D.; Samareh, Jamshid A.

    2004-01-01

    In this paper, results of a study of structural layouts of post-WWII aircraft are presented. This study was undertaken to provide the background information necessary to determine typical layouts, design practices, and industry trends in aircraft structural design. Design decisions are often predicated not on performance-related criteria, but rather on such factors as manufacturability, maintenance access, and of course cost. For this reason, a thorough understanding of current best practices in the industry is required as an input for the design optimization process. To determine these best practices and industry trends, a large number of aircraft structural cutaway illustrations were analyzed for five different aircraft categories (commercial transport jets, business jets, combat jet aircraft, single engine propeller aircraft, and twin-engine propeller aircraft). Several aspects of wing design and fuselage design characteristics are presented here for the commercial transport and combat aircraft categories. A great deal of commonality was observed for transport structure designs over a range of eras and manufacturers. A much higher degree of variability in structural designs was observed for the combat aircraft, though some discernable trends were observed as well.

  16. Yawed-Rolling Tire Mechanical Properties Testing of the Navy T-45 Aircraft Tires

    NASA Technical Reports Server (NTRS)

    Daugherty, Robert H.

    2000-01-01

    The T-45 Goshawk is a United States Navy Jet aircraft used primarily as a trainer. The aircraft design makes use of "off the shelf" hardware as much as possible and was found to have unusual directional control issues during around operations. The aircraft was involved in numerous pilot-induced-oscillation incidents as well as observed to have unusual directional control reactions to failed main gear tires, a condition that is normally handled relatively easily by conventional aircraft steering control techniques. The behavior of the aircraft's tires had previously been modeled in simulators as a result of approximations provided in 40-year-old reference publications. Since knowledge of the true tire cornering and braking behavior is essential to modeling, understanding, and fixing directional control problems, the United States Navy requested assistance from the NASA Langley Research Center's (LARC) Aircraft Landing Dynamics Facility (ALDF) to define the yawed-rolling mechanical properties of the T-45 aircraft tires. The purpose of this report is to document the results of testing the subject tires at the NASA LaRC ALDF in September 1998. Brief descriptions of the Instrumented Tire Test Vehicle (ITTV) are included to familiarize the reader with the ITTV capabilities, data acquisition system, test and measurement techniques, data accuracy, and analysis and presentation of the testing results.

  17. Computerized structural mechanics for 1990's: Advanced aircraft needs

    NASA Technical Reports Server (NTRS)

    Viswanathan, A. V.; Backman, B. F.

    1989-01-01

    The needs for computerized structural mechanics (CSM) as seen from the standpoint of the aircraft industry are discussed. These needs are projected into the 1990's with special focus on the new advanced materials. Preliminary design/analysis, research, and detail design/analysis are identified as major areas. The role of local/global analyses in these different areas is discussed. The lessons learned in the past are used as a basis for the design of a CSM framework that could modify and consolidate existing technology and include future developments in a rational and useful way. A philosophy is stated, and a set of analyses needs driven by the emerging advanced composites is enumerated. The roles of NASA, the universities, and the industry are identified. Finally, a set of rational research targets is recommended based on both the new types of computers and the increased complexity the industry faces. Computerized structural mechanics should be more than new methods in structural mechanics and numerical analyses. It should be a set of engineering applications software products that combines innovations in structural mechanics, numerical analysis, data processing, search and display features, and recent hardware advances and is organized in a framework that directly supports the design process.

  18. 78 FR 18932 - Public Meeting: Unmanned Aircraft Systems Test Site Program; Privacy Approach

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-28

    ... the Federal Register on February 22, 2013 (78 FR 12259), Docket No. FAA-2013-0061. In that document... operation of unmanned aircraft systems within the test site program (78 FR 12259). The proposed...

  19. Fuel containment, lightning protection and damage tolerance in large composite primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Griffin, Charles F.; James, Arthur M.

    1985-01-01

    The damage-tolerance characteristics of high strain-to-failure graphite fibers and toughened resins were evaluated. Test results show that conventional fuel tank sealing techniques are applicable to composite structures. Techniques were developed to prevent fuel leaks due to low-energy impact damage. For wing panels subjected to swept stroke lightning strikes, a surface protection of graphite/aluminum wire fabric and a fastener treatment proved effective in eliminating internal sparking and reducing structural damage. The technology features developed were incorporated and demonstrated in a test panel designed to meet the strength, stiffness, and damage tolerance requirements of a large commercial transport aircraft. The panel test results exceeded design requirements for all test conditions. Wing surfaces constructed with composites offer large weight savings if design allowable strains for compression can be increased from current levels.

  20. Aircraft Structural Mass Property Prediction Using Conceptual-Level Structural Analysis

    NASA Technical Reports Server (NTRS)

    Sexstone, Matthew G.

    1998-01-01

    This paper describes a methodology that extends the use of the Equivalent LAminated Plate Solution (ELAPS) structural analysis code from conceptual-level aircraft structural analysis to conceptual-level aircraft mass property analysis. Mass property analysis in aircraft structures has historically depended upon parametric weight equations at the conceptual design level and Finite Element Analysis (FEA) at the detailed design level. ELAPS allows for the modeling of detailed geometry, metallic and composite materials, and non-structural mass coupled with analytical structural sizing to produce high-fidelity mass property analyses representing fully configured vehicles early in the design process. This capability is especially valuable for unusual configuration and advanced concept development where existing parametric weight equations are inapplicable and FEA is too time consuming for conceptual design. This paper contrasts the use of ELAPS relative to empirical weight equations and FEA. ELAPS modeling techniques are described and the ELAPS-based mass property analysis process is detailed. Examples of mass property stochastic calculations produced during a recent systems study are provided. This study involved the analysis of three remotely piloted aircraft required to carry scientific payloads to very high altitudes at subsonic speeds. Due to the extreme nature of this high-altitude flight regime, few existing vehicle designs are available for use in performance and weight prediction. ELAPS was employed within a concurrent engineering analysis process that simultaneously produces aerodynamic, structural, and static aeroelastic results for input to aircraft performance analyses. The ELAPS models produced for each concept were also used to provide stochastic analyses of wing structural mass properties. The results of this effort indicate that ELAPS is an efficient means to conduct multidisciplinary trade studies at the conceptual design level.

  1. Aircraft Structural Mass Property Prediction Using Conceptual-Level Structural Analysis

    NASA Technical Reports Server (NTRS)

    Sexstone, Matthew G.

    1998-01-01

    This paper describes a methodology that extends the use of the Equivalent LAminated Plate Solution (ELAPS) structural analysis code from conceptual-level aircraft structural analysis to conceptual-level aircraft mass property analysis. Mass property analysis in aircraft structures has historically depended upon parametric weight equations at the conceptual design level and Finite Element Analysis (FEA) at the detailed design level ELAPS allows for the modeling of detailed geometry, metallic and composite materials, and non-structural mass coupled with analytical structural sizing to produce high-fidelity mass property analyses representing fully configured vehicles early in the design process. This capability is especially valuable for unusual configuration and advanced concept development where existing parametric weight equations are inapplicable and FEA is too time consuming for conceptual design. This paper contrasts the use of ELAPS relative to empirical weight equations and FEA. ELAPS modeling techniques are described and the ELAPS-based mass property analysis process is detailed Examples of mass property stochastic calculations produced during a recent systems study are provided This study involved the analysis of three remotely piloted aircraft required to carry scientific payloads to very high altitudes at subsonic speeds. Due to the extreme nature of this high-altitude flight regime,few existing vehicle designs are available for use in performance and weight prediction. ELAPS was employed within a concurrent engineering analysis process that simultaneously produces aerodynamic, structural, and static aeroelastic results for input to aircraft performance analyses. The ELAPS models produced for each concept were also used to provide stochastic analyses of wing structural mass properties. The results of this effort indicate that ELAPS is an efficient means to conduct multidisciplinary trade studies at the conceptual design level.

  2. En route noise of turboprop aircraft and their acceptability: Report of tests

    NASA Technical Reports Server (NTRS)

    Held, Wolf

    1990-01-01

    The development of propfan-powered aircraft has been observed with great interest. It is obvious that during cruising flight, the aircraft powerplant (propellers) cause a noise clearly perceivable on the ground. It is the audible frequency spectrum of the propfan powerplants relative to the high tip speeds that presents the problem. A flight test was conducted on 30 April, 1989 at the Frankfurt Airport. Results of the test flight are present.

  3. A Large Hemi-Anechoic Enclosure for Community-Compatible Aeroacoustic Testing of Aircraft Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Cooper, Beth A.

    1993-01-01

    A large hemi-anechoic (absorptive walls and acoustically hard floor) noise control enclosure has been erected around a complex of test stands at the NASA Lewis Research Center in Cleveland, Ohio. This new state-of-the-art Aeroacoustic Propulsion Laboratory (APL) provides an all-weather, semisecure test environment while limiting noise to acceptable levels in surrounding residential neighborhoods. The 39.6 m (130 ft) diameter geodesic dome structure houses the new Nozzle Aeroacoustic Test Rig (NATR), an ejector-powered M = 0.3 free jet facility for acoustic testing of supersonic aircraft exhaust nozzles and turbomachinery. A multi-axis, force-measuring Powered Lift Facility (PLF) stand for testing of Short Takeoff Vertical Landing (STOVL) vehicles is also located within the dome. The design of the Aeroacoustic Propulsion Laboratory efficiently accomodates the research functions of two separate test rigs, one of which (NATR) requires a specialized environment for taking acoustic measurements. Absorptive fiberglass wedge treatment on the interior surface of the dome provides a hemi-anechoic interior environment for obtaining the accurate acoustic measurements required to meet research program goals. The APL is the first known geodesic dome structure to incorporate transmission-loss properties as well as interior absorption into a free-standing, community-compatible, hemi-anechoic test facility.

  4. Consolidation of graphite thermoplastic textile preforms for primary aircraft structure

    NASA Technical Reports Server (NTRS)

    Suarez, J.; Mahon, J.

    1991-01-01

    The use of innovative cost effective material forms and processes is being considered for fabrication of future primary aircraft structures. Processes that have been identified as meeting these goals are textile preforms that use resin transfer molding (RTM) and consolidation forming. The Novel Composites for Wing and Fuselage Applications (NCWFA) program has as its objective the integration of innovative design concepts with cost effective fabrication processes to develop damage-tolerant structures that can perform at a design ultimate strain level of 6000 micro-inch/inch. In this on-going effort, design trade studies were conducted to arrive at advanced wing designs that integrate new material forms with innovative structural concepts and cost effective fabrication methods. The focus has been on minimizing part count (mechanical fasteners, clips, number of stiffeners, etc.), by using cost effective textile reinforcement concepts that provide improved damage tolerance and out-of-plane load capability, low-cost resin transfer molding processing, and thermoplastic forming concepts. The fabrication of representative Y spars by consolidation methods will be described. The Y spars were fabricated using AS4 (6K)/PEEK 150g commingled angle interlock 0/90-degree woven preforms with +45-degree commingled plies stitched using high strength Toray carbon thread and processed by autoclave consolidation.

  5. Structural Optimization Methodology for Rotating Disks of Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Armand, Sasan C.

    1995-01-01

    In support of the preliminary evaluation of various engine technologies, a methodology has been developed for structurally designing the rotating disks of an aircraft engine. The structural design methodology, along with a previously derived methodology for predicting low-cycle fatigue life, was implemented in a computer program. An interface computer program was also developed that gathers the required data from a flowpath analysis program (WATE) being used at NASA Lewis. The computer program developed for this study requires minimum interaction with the user, thus allowing engineers with varying backgrounds in aeropropulsion to successfully execute it. The stress analysis portion of the methodology and the computer program were verified by employing the finite element analysis method. The 10th- stage, high-pressure-compressor disk of the Energy Efficient Engine Program (E3) engine was used to verify the stress analysis; the differences between the stresses and displacements obtained from the computer program developed for this study and from the finite element analysis were all below 3 percent for the problem solved. The computer program developed for this study was employed to structurally optimize the rotating disks of the E3 high-pressure compressor. The rotating disks designed by the computer program in this study were approximately 26 percent lighter than calculated from the E3 drawings. The methodology is presented herein.

  6. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    PubMed

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  7. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    PubMed Central

    Di Sante, Raffaella

    2015-01-01

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques. PMID:26263987

  8. Simulation of an Impact Test of the All-Composite Lear Fan Aircraft

    NASA Technical Reports Server (NTRS)

    Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

    2002-01-01

    An MSC.Dytran model of an all-composite Lear Fan aircraft fuselage was developed to simulate an impact test conducted at the NASA Langley Research Center Impact Dynamics Research Facility (IDRF). The test was the second of two Lear Fan impact tests. The purpose of the second test was to evaluate the performance of retrofitted composite energy-absorbing floor beams. A computerized photogrammetric survey was performed to provide airframe geometric coordinates, and over 5000 points were processed and imported into MSC.Patran via an IGES file. MSC.Patran was then used to develop the curves and surfaces and to mesh the finite element model. A model of the energy-absorbing floor beams was developed separately and then integrated into the Lear Fan model. Structural responses of components such as the wings were compared with experimental data or previously published analytical data wherever possible. Comparisons with experimental results were used to guide structural model modifications to improve the simulation performance. This process was based largely on qualitative (video and still camera images and post-test inspections) rather than quantitative results due to the relatively few accelerometers attached to the structure.

  9. Development and testing of the Perseus proof-of-concept aircraft. Final report

    SciTech Connect

    Langford, J.S.

    1993-02-26

    Many areas of global climate change research could benefit from a flexible, affordable, and near-term platform that could provide in situ measurements in the upper troposphere and lower stratosphere. To provide such a capability, the Perseus unmanned science research aircraft was proposed in 1989. As a first step toward the development of Perseus, a proof-of-concept (POC) demonstrator was constructed and tested during 1990 and 1991. The POC was a full scale Perseus airframe intended to validate the structural, aerodynamic, and flight control technologies for the Perseus within a total budget of about $1.5 million. Advanced propulsion systems needed for the operational Perseus were not covered in the POC program due to funding limitations. This report documents the design, development, and testing of the Perseus POC.

  10. Structural efficiency study of graphite-epoxy aircraft rib structures

    NASA Technical Reports Server (NTRS)

    Swanson, Gary D.; Gurdal, Zafer; Starnes, James H., Jr.

    1988-01-01

    Attention is given to the structural efficiencies obtainable with optimally designed graphite/epoxy wing rib panel configurations that are potentially economically manufacturable. Some ribs are commonly used as fuel cell closeout panels, and are accordingly subjected to out-of-plane pressure loads in addition to the in-plane axial compressive and shear loads resulting from the wing loading. The present minimum-weight panel designs satisfy buckling and strength constraints for wing rib panels subjected to a wide range of combined load conditions.

  11. Orbiter/shuttle carrier aircraft separation: Wind tunnel, simulation, and flight test overview and results

    NASA Technical Reports Server (NTRS)

    Homan, D. J.; Denison, D. E.; Elchert, K. C.

    1980-01-01

    A summary of the approach and landing test phase of the space shuttle program is given from the orbiter/shuttle carrier aircraft separation point of view. The data and analyses used during the wind tunnel testing, simulation, and flight test phases in preparation for the orbiter approach and landing tests are reported.

  12. Analysis of interior noise ground and flight test data for advanced turboprop aircraft applications

    NASA Technical Reports Server (NTRS)

    Simpson, M. A.; Tran, B. N.

    1991-01-01

    Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight tests with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine.

  13. Study of improved modeling and solution procedures for nonlinear analysis. [aircraft-like structures

    NASA Technical Reports Server (NTRS)

    Kamat, M. P.

    1979-01-01

    An evaluation of the ACTION computer code on an aircraft like structure is presented. This computer program proved adequate in predicting gross response parameters in structures which undergo severe localized cross sectional deformations.

  14. Full-scale testing, production and cost analysis data for the advanced composite stabilizer for Boeing 737 aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parsons, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1983-01-01

    The full scale ground test, ground vibration test, and flight tests conducted to demonstrate a composite structure stabilizer for the Boeing 737 aircraft and obtain FAA certification are described. Detail tools, assembly tools, and overall production are discussed. Cost analyses aspects covered include production costs, composite material usage factors, and cost comparisons.

  15. Qualification needs for advanced integrated aircraft

    NASA Technical Reports Server (NTRS)

    Mackall, D. A.

    1985-01-01

    In an effort to achieve maximum aircraft performance, designers are integrating aircraft systems. The characteristics of aerodynamics, vehicle structure, and propulsion systems are being integrated and controlled through embedded, often flight critical, electronic systems. The qualification needs for such highly integrated aircraft systems are addressed. Based on flight experience with research aircraft, a set of test capabilities is described which allows for complete and efficient qualification of advanced integrated aircraft.

  16. Impact Testing of Composites for Aircraft Engine Fan Cases

    NASA Technical Reports Server (NTRS)

    Roberts, Gary D.; Revilock, Duane M.; Binienda, Wieslaw K.; Nie, Walter Z.; Mackenzie, S. Ben; Todd, Kevin B.

    2001-01-01

    Before composite materials can be considered for use in the fan case of a commercial jet engine, the performance of a composite structure under blade-out loads needs to be demonstrated. The objective of this program is to develop an efficient test and analysis method for evaluating potential composite case concepts. Ballistic impact tests were performed on laminated glass/epoxy composites in order to identify potential failure modes and to provide data for analysis. Flat 7x7 in. panels were impacted with cylindrical titanium projectiles, and 15 in. diameter half-rings were impacted with wedge-shaped titanium projectiles. Composite failure involved local fiber fracture as well as tearing and delamination on a larger scale. A 36 in. diameter full-ring subcomponent was proposed for larger scale testing. Explicit, transient, finite element analyses were used to evaluate impact dynamics and subsequent global deformation for the proposed full-ring subcomponent test. Analyses on half-ring and quarter ring configurations indicated that less expensive smaller scale tests could be used to screen potential composite concepts when evaluation of local impact damage is the primary concern.

  17. Flight test evaluation of a method to determine the level flight performance propeller-driven aircraft

    NASA Technical Reports Server (NTRS)

    Cross, E. J., Jr.

    1976-01-01

    A procedure is developed for deriving the level flight drag and propulsive efficiency of propeller-driven aircraft. This is a method in which the overall drag of the aircraft is expressed in terms of the measured increment of power required to overcome a corresponding known increment of drag. The aircraft is flown in unaccelerated, straight and level flight, and thus includes the effects of the propeller drag and slipstream. Propeller efficiency and airplane drag are computed on the basis of data obtained during flight test and do not rely on the analytical calculations of inadequate theory.

  18. Development of control laws for a flight test maneuver autopilot for an F-15 aircraft

    NASA Technical Reports Server (NTRS)

    Alag, G. S.; Duke, E. L.

    1985-01-01

    An autopilot can be used to provide precise control to meet the demanding requirements of flight research maneuvers with high-performance aircraft. The development of control laws within the context of flight test maneuver requirements is discussed. The control laws are developed using eigensystem assignment and command generator tracking. The eigenvalues and eigenvectors are chosen to provide the necessary handling qualities, while the command generator tracking enables the tracking of a specified state during the maneuver. The effectiveness of the control laws is illustrated by their application to an F-15 aircraft to ensure acceptable aircraft performance during a maneuver.

  19. A study on the utilization of advanced composites in commercial aircraft wing structure: Executive summary

    NASA Technical Reports Server (NTRS)

    Watts, D. J.

    1978-01-01

    The overall wing study objectives are to study and plan the effort by commercial transport aircraft manufacturers to accomplish the transition from current conventional materials and practices to extensive use of advanced composites in wings of aircraft that will enter service in the 1985-1990 time period. Specific wing study objectives are to define the technology and data needed to support an aircraft manufacturer's commitment to utilize composites primary wing structure in future production aircraft and to develop plans for a composite wing technology program which will provide the needed technology and data.

  20. In-flight acoustic testing techniques using the YO-3A Acoustic Research Aircraft

    NASA Technical Reports Server (NTRS)

    Cross, J. L.; Watts, M. E.

    1984-01-01

    This report discusses the flight testing techniques and equipment employed during air-to-air acoustic testing of helicopters at Ames Research Center. The in flight measurement technique used enables acoustic data to be obtained without the limitations of anechoic chambers or the multitude of variables encountered in ground based flyover testing. The air-to-air testing is made possible by the NASA YO-3A Acoustic Research Aircraft. This "Quiet Aircraft' is an acoustically instrumented version of a quiet observation aircraft manufactured for the military. To date, tests with the following aircraft have been conducted: YO-3A background noise; Hughes 500D; Hughes AH-64; Bell AH-1S; Bell AH-1G. Several system upgrades are being designed and implemented to improve the quality of data. This report will discuss not only the equipment involved and aircraft tested, but also the techniques used in these tests. In particular, formation flying position locations, and the test matrices will be discussed. Examples of data taken will also be presented.

  1. Test of prototype liquid-water-content meter for aircraft use

    NASA Technical Reports Server (NTRS)

    Gerber, Hermann E.

    1993-01-01

    This report describes the effort undertaken to meet the objectives of National Science Foundation Grant ATM-9207345 titled 'Test of Prototype Liquid-Water-Content Meter for Aircraft Use.' Three activities were proposed for testing the new aircraft instrument, PVM-100A: (1) Calibrate the PVM-100A in a facility where the liquid-water-content (LWC) channel, and the integrated surface area channel (PSA) could be compared to standard means for LWC and PSA measurements. Scaling constant for the channels were to be determined in this facility. The fog/wind tunnel at ECN, Petten, The Netherlands was judged the most suitable facility for this effort. (2) Expose the PVM-100A to high wind speeds similar to those expected on research aircraft, and test the anti-icing heaters on the PVM-100A under typical icing conditions expected in atmospheric clouds. The high-speed icing tunnel at NRC, Ottawa, Canada was to be utilized. (3) Operate the PVM-100A on an aircraft during cloud penetrations to determine its stability and practicality for such measurements. The C-131A aircraft of the University of Washington was the aircraft of opportunity for these-tests, which were to be conducted during the 4-week Atlantic Stratocumulus Transition Experiment (ASTEX) in June of 1992.

  2. Impact dynamics research facility for full-scale aircraft crash testing

    NASA Technical Reports Server (NTRS)

    Vaughan, V. L. J.; Alfaro-Bou, E.

    1976-01-01

    An impact dynamics research facility (IDRF) was developed to crash test full-scale general aviation aircraft under free-flight test conditions. The aircraft are crashed into the impact surface as free bodies; a pendulum swing method is used to obtain desired flight paths and velocities. Flight paths up to -60 deg and aircraft velocities along the flight paths up to about 27.0 m/s can be obtained with a combination of swing-cable lengths and release heights made available by a large gantry. Seven twin engine, 2721-kg aircraft were successfully crash tested at the facility, and all systems functioned properly. Acquisition of data from signals generated by accelerometers on board the aircraft and from external and onboard camera coverage was successful in spite of the amount of damage which occurred during each crash. Test parameters at the IDRF are controllable with flight path angles accurate within 8 percent, aircraft velocity accurate within 6 percent, pitch angles accurate to 4.25 deg, and roll and yaw angles acceptable under wind velocities up to 4.5 m/s.

  3. Crack propagation monitoring in a full-scale aircraft fatigue test based on guided wave-Gaussian mixture model

    NASA Astrophysics Data System (ADS)

    Qiu, Lei; Yuan, Shenfang; Bao, Qiao; Mei, Hanfei; Ren, Yuanqiang

    2016-05-01

    For aerospace application of structural health monitoring (SHM) technology, the problem of reliable damage monitoring under time-varying conditions must be addressed and the SHM technology has to be fully validated on real aircraft structures under realistic load conditions on ground before it can reach the status of flight test. In this paper, the guided wave (GW) based SHM method is applied to a full-scale aircraft fatigue test which is one of the most similar test status to the flight test. To deal with the time-varying problem, a GW-Gaussian mixture model (GW-GMM) is proposed. The probability characteristic of GW features, which is introduced by time-varying conditions is modeled by GW-GMM. The weak cumulative variation trend of the crack propagation, which is mixed in time-varying influence can be tracked by the GW-GMM migration during on-line damage monitoring process. A best match based Kullback–Leibler divergence is proposed to measure the GW-GMM migration degree to reveal the crack propagation. The method is validated in the full-scale aircraft fatigue test. The validation results indicate that the reliable crack propagation monitoring of the left landing gear spar and the right wing panel under realistic load conditions are achieved.

  4. Full-scale flammability test data for validation of aircraft fire mathematical models

    NASA Technical Reports Server (NTRS)

    Kuminecz, J. F.; Bricker, R. W.

    1982-01-01

    Twenty-five large scale aircraft flammability tests were conducted in a Boeing 737 fuselage at the NASA Johnson Space Center (JSC). The objective of this test program was to provide a data base on the propagation of large scale aircraft fires to support the validation of aircraft fire mathematical models. Variables in the test program included cabin volume, amount of fuel, fuel pan area, fire location, airflow rate, and cabin materials. A number of tests were conducted with jet A-1 fuel only, while others were conducted with various Boeing 747 type cabin materials. These included urethane foam seats, passenger service units, stowage bins, and wall and ceiling panels. Two tests were also included using special urethane foam and polyimide foam seats. Tests were conducted with each cabin material individually, with various combinations of these materials, and finally, with all materials in the cabin. The data include information obtained from approximately 160 locations inside the fuselage.

  5. Microsensors and MEMS for health monitoring of composite and aircraft structures in flight

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Varadan, Vasundara V.

    1999-07-01

    Microsensors and Microelectromechanical Systems (MEMS) are currently being applied to the structural health monitoring of critical aircraft components. The approach integrates acoustic emission, strain gauges, MEMS accelerometers and vibration monitoring devices with signal processing electronics to provide real-time indicators of incipient failure of aircraft components with a known history of catastrophic failure due to fracture.

  6. Development of fiber optic sensors for advanced aircraft testing and control

    NASA Astrophysics Data System (ADS)

    Meller, Scott A.; Jones, Mark E.; Wavering, Thomas A.; Kozikowski, Carrie L.; Murphy, Kent A.

    1999-02-01

    Optical fiber sensors, because of the small size, low weight, extremely high information carrying capability, immunity to electromagnetic interference, and large operational temperature range, provide numerous advantages over conventional electrically based sensors. This paper presents preliminary results from optical fiber sensor design for monitoring acceleration on aircraft. Flight testing of the final accelerometer design will be conducted on the F-18 Systems Research Aircraft at NASA Dryden Flight Research Center in Edwards, CA.

  7. Flight test techniques for validating simulated nuclear electromagnetic pulse aircraft responses

    NASA Technical Reports Server (NTRS)

    Winebarger, R. M.; Neely, W. R., Jr.

    1984-01-01

    An attempt has been made to determine the effects of nuclear EM pulses (NEMPs) on aircraft systems, using a highly instrumented NASA F-106B to document the simulated NEMP environment at the Kirtland Air Force Base's Vertically Polarized Dipole test facility. Several test positions were selected so that aircraft orientation relative to the test facility would be the same in flight as when on the stationary dielectric stand, in order to validate the dielectric stand's use in flight configuration simulations. Attention is given to the flight test portions of the documentation program.

  8. Development and flight test of an experimental maneuver autopilot for a highly maneuverable aircraft

    NASA Technical Reports Server (NTRS)

    Duke, Eugene L.; Jones, Frank P.; Roncoli, Ralph B.

    1986-01-01

    This report presents the development of an experimental flight test maneuver autopilot (FTMAP) for a highly maneuverable aircraft. The essence of this technique is the application of an autopilot to provide precise control during required flight test maneuvers. This newly developed flight test technique is being applied at the Dryden Flight Research Facility of NASA Ames Research Center. The FTMAP is designed to increase the quantity and quality of data obtained in test flight. The technique was developed and demonstrated on the highly maneuverable aircraft technology (HiMAT) vehicle. This report describes the HiMAT vehicle systems, maneuver requirements, FTMAP development process, and flight results.

  9. Application of supersonic particle deposition to enhance the structural integrity of aircraft structures

    NASA Astrophysics Data System (ADS)

    Matthews, N.; Jones, R.; Sih, G. C.

    2014-01-01

    Aircraft metal components and structures are susceptible to environmental degradation throughout their original design life and in many cases their extended lives. This paper summarizes the results of an experimental program to evaluate the ability of Supersonic Particle Deposition (SPD), also known as cold spray, to extend the limit of validity (LOV) of aircraft structural components and to restore the structural integrity of corroded panels. In this study [LU1]the potential for the SPD to seal the mechanically fastened joints and for this seal to remain intact even in the presence of multi-site damage (MSD) has been evaluated. By sealing the joint the onset of corrosion damage in the joint can be significantly retarded, possibly even eliminated, thereby dramatically extending the LOV of mechanically fastened joints. The study also shows that SPD can dramatically increase the damage tolerance of badly corroded wing skins.

  10. Rotary Balance Wind Tunnel Testing for the FASER Flight Research Aircraft

    NASA Technical Reports Server (NTRS)

    Denham, Casey; Owens, D. Bruce

    2016-01-01

    Flight dynamics research was conducted to collect and analyze rotary balance wind tunnel test data in order to improve the aerodynamic simulation and modeling of a low-cost small unmanned aircraft called FASER (Free-flying Aircraft for Sub-scale Experimental Research). The impetus for using FASER was to provide risk and cost reduction for flight testing of more expensive aircraft and assist in the improvement of wind tunnel and flight test techniques, and control laws. The FASER research aircraft has the benefit of allowing wind tunnel and flight tests to be conducted on the same model, improving correlation between wind tunnel, flight, and simulation data. Prior wind tunnel tests include a static force and moment test, including power effects, and a roll and yaw damping forced oscillation test. Rotary balance testing allows for the calculation of aircraft rotary derivatives and the prediction of steady-state spins. The rotary balance wind tunnel test was conducted in the NASA Langley Research Center (LaRC) 20-Foot Vertical Spin Tunnel (VST). Rotary balance testing includes runs for a set of given angular rotation rates at a range of angles of attack and sideslip angles in order to fully characterize the aircraft rotary dynamics. Tests were performed at angles of attack from 0 to 50 degrees, sideslip angles of -5 to 10 degrees, and non-dimensional spin rates from -0.5 to 0.5. The effects of pro-spin elevator and rudder deflection and pro- and anti-spin elevator, rudder, and aileron deflection were examined. The data are presented to illustrate the functional dependence of the forces and moments on angle of attack, sideslip angle, and angular rate for the rotary contributions to the forces and moments. Further investigation is necessary to fully characterize the control effectors. The data were also used with a steady state spin prediction tool that did not predict an equilibrium spin mode.

  11. Comparison of model and flight test data for an augmented jet flap STOL research aircraft

    NASA Technical Reports Server (NTRS)

    Cook, W. L.; Whittley, D. C.

    1975-01-01

    Aerodynamic design data for the Augmented Jet Flap STOL Research Aircraft or commonly known as the Augmentor-Wing Jet-STOL Research Aircraft was based on results of tests carried out on a large scale research model in the NASA Ames 40- by 80-Foot Wind Tunnel. Since the model differs in some respects from the aircraft, precise correlation between tunnel and flight test is not expected, however the major areas of confidence derived from the wind tunnel tests are delineated, and for the most part, tunnel results compare favorably with flight experience. In some areas the model tests were known to be nonrepresentative so that a degree of uncertainty remained: these areas of greater uncertainty are identified, and discussed in the light of subsequent flight tests.

  12. Validation of Methodology for Estimating Aircraft Unsteady Aerodynamic Parameters from Dynamic Wind Tunnel Tests

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.; Klein, Vladislav

    2003-01-01

    A basic problem in flight dynamics is the mathematical formulation of the aerodynamic model for aircraft. This study is part of an ongoing effort at NASA Langley to develop a more general formulation of the aerodynamic model for aircraft that includes nonlinear unsteady aerodynamics and to develop appropriate test techniques that facilitate identification of these models. A methodology for modeling and testing using wide-band inputs to estimate the unsteady form of the aircraft aerodynamic model was developed previously but advanced test facilities were not available at that time to allow complete validation of the methodology. The new model formulation retained the conventional static and rotary dynamic terms but replaced conventional acceleration terms with more general indicial functions. In this study advanced testing techniques were utilized to validate the new methodology for modeling. Results of static, conventional forced oscillation, wide-band forced oscillation, oscillatory coning, and ramp tests are presented.

  13. Aircraft Integration and Flight Testing of 4STAR

    SciTech Connect

    Flynn, CJ; Kassianov, E; Russell, P; Redemann, J; Dunagan, S; Holben, B

    2012-10-12

    Under funding from the U.S. Dept. of Energy, in conjunction with a funded NASA 2008 ROSES proposal, with internal support from Battelle Pacific Northwest Division (PNWD), and in collaboration with NASA Ames Research Center, we successfully integrated the Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR-Air) instrument for flight operation aboard Battelle’s G-1 aircraft and conducted a series of airborne and ground-based intensive measurement campaigns (hereafter referred to as “intensives”) for the purpose of maturing the initial 4STAR-Ground prototype to a flight-ready science-ready configuration.

  14. Wind-tunnel testing of VTOL and STOL aircraft

    NASA Technical Reports Server (NTRS)

    Heyson, H. H.

    1978-01-01

    The basic concepts of wind-tunnel boundary interference are discussed and the development of the theory for VTOL-STOL aircraft is described. Features affecting the wall interference, such as wake roll-up, configuration differences, recirculation limits, and interference nonuniformity, are discussed. The effects of the level of correction on allowable model size are shown to be amenable to generalized presentation. Finally, experimental confirmation of wind-tunnel interference theory is presented for jet-flap, rotor, and fan-in-wing models.

  15. Advanced composite structural concepts and material technologies for primary aircraft structures

    NASA Technical Reports Server (NTRS)

    Jackson, Anthony

    1991-01-01

    Structural weight savings using advanced composites have been demonstrated for many years. Most military aircraft today use these materials extensively and Europe has taken the lead in their use in commercial aircraft primary structures. A major inhibiter to the use of advanced composites in the United States is cost. Material costs are high and will remain high relative to aluminum. The key therefore lies in the significant reduction in fabrication and assembly costs. The largest cost in most structures today is assembly. As part of the NASA Advanced Composite Technology Program, Lockheed Aeronautical Systems Company has a contract to explore and develop advanced structural and manufacturing concepts using advanced composites for transport aircraft. Wing and fuselage concepts and related trade studies are discussed. These concepts are intended to lower cost and weight through the use of innovative material forms, processes, structural configurations and minimization of parts. The approach to the trade studies and the downselect to the primary wing and fuselage concepts is detailed. The expectations for the development of these concepts is reviewed.

  16. Metal aircraft structural elements reinforced with graphite filamentary composites

    NASA Technical Reports Server (NTRS)

    Berg, K. R.; Ramsey, J.

    1972-01-01

    Strain compatibility equations are used to evaluate the thermal stresses existing when unidirectional graphite composites are bonded to aluminum structures. Based on thermal stresses and optimum placement of the composite, skin-stringer aluminum panels are optimized for minimum weight compression panels with selective composite reinforcement. Composite reinforced skin-stringer panels are thermal cycled to determine the effect of thermal fatigue on structural integrity. Both cycled and uncycled panels are tested in compression and tension. Test results are correlated with predicted loads. Use of filamentary graphite composites is an efficient method of reinforcing metal structures, but care must be taken to minimize thermal stresses.

  17. Subsonic Ultra Green Aircraft Research: Phase II- Volume III-Truss Braced Wing Aeroelastic Test Report

    NASA Technical Reports Server (NTRS)

    Bradley, Marty K.; Allen, Timothy J.; Droney, Christopher

    2014-01-01

    This Test Report summarizes the Truss Braced Wing (TBW) Aeroelastic Test (Task 3.1) work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team, which includes the time period of February 2012 through June 2014. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, Virginia Tech, and NextGen Aeronautics. The model was fabricated by NextGen Aeronautics and designed to meet dynamically scaled requirements from the sized full scale TBW FEM. The test of the dynamically scaled SUGAR TBW half model was broken up into open loop testing in December 2013 and closed loop testing from January 2014 to April 2014. Results showed the flutter mechanism to primarily be a coalescence of 2nd bending mode and 1st torsion mode around 10 Hz, as predicted by analysis. Results also showed significant change in flutter speed as angle of attack was varied. This nonlinear behavior can be explained by including preload and large displacement changes to the structural stiffness and mass matrices in the flutter analysis. Control laws derived from both test system ID and FEM19 state space models were successful in suppressing flutter. The control laws were robust and suppressed flutter for a variety of Mach, dynamic pressures, and angle of attacks investigated.

  18. New nondestructive techniques for the detection and quantification of corrosion in aircraft structures

    NASA Technical Reports Server (NTRS)

    Winfree, W. P.; Cramer, K. E.; Johnston, P. H.; Namkung, M.

    1995-01-01

    An overview is presented of several techniques under development at NASA Langley Research Center for detection and quantification of corrosion in aircraft structures. The techniques have been developed as part of the NASA Airframe Structural Integrity Program. The techniques focus on the detection of subsurface corrosion in thin laminated structures. Results are presented on specimens with both manufactured defects, for calibration of the techniques, and on specimens removed from aircraft.

  19. Development of aircraft brake materials. [evaluation of metal and ceramic materials in sliding tests simulation of aircraft braking

    NASA Technical Reports Server (NTRS)

    Ho, T. L.; Peterson, M. B.

    1974-01-01

    The requirements of brake materials were outlined and a survey made to select materials to meet the needs of high temperature brakes. A number of metals and ceramic materials were selected and evaluated in sliding tests which simulated aircraft braking. Nickel, molybdenum tungsten, Zr02, high temperature cements and carbons were tested. Additives were then incorporated into these materials to optimize their wear or strength behavior with particular emphasis on nickel and molybdenum base materials and a high temperature potassium silicate cement. Optimum materials were developed which improved wear behavior over conventional brake materials in the simulated test. The best materials are a nickel, aluminum oxide, lead tungstate composition containing graphite or molybdenum disulphite; a molybdenum base material containing LPA100 (an intermetallic compound of cobalt, molybdenum, and silicon); and a carbon material (P5).

  20. Large space structures testing

    NASA Technical Reports Server (NTRS)

    Waites, Henry; Worley, H. Eugene

    1987-01-01

    There is considerable interest in the development of testing concepts and facilities that accurately simulate the pathologies believed to exist in future spacecraft. Both the Government and Industry have participated in the development of facilites over the past several years. The progress and problems associated with the development of the Large Space Structure Test Facility at the Marshall Flight Center are presented. This facility was in existence for a number of years and its utilization has run the gamut from total in-house involvement, third party contractor testing, to the mutual participation of other Government Agencies in joint endeavors.

  1. Real-time aircraft structural damage identification with flight condition variations

    NASA Astrophysics Data System (ADS)

    Lew, Jiann-Shiun; Loh, Chin-Hsiung

    2012-04-01

    This paper presents a real-time structural damage identification method for aircraft with flight condition variations. The proposed approach begins by identifying the dynamic models under various test conditions from time-domain input/output data. A singular value decomposition technique is then used to characterize and quantify the parameter uncertainties from the identified models. The uncertainty coordinates, corresponding to the identified principal directions, of the identified models are computed, and the residual errors between the identified uncertainty coordinates and the estimated uncertainty coordinates of the health structure are used to identify damage status. A correlation approach is applied to identify damage type and intensity, based on the difference between the identified parameters and the estimated parameters of the healthy structure. The proposed approach is demonstrated by application to the Benchmark Active Controls Technology (BACT) wind-tunnel model.

  2. Experimental and Numerical Investigation of Wide Area Blunt Impact Damage to Composite Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Chen, Zhi Ming

    Due to their high performance and weight efficiency, carbon fiber composites are increasingly being used in aircraft primary structure applications. Exposed composite structures (e.g., fuselage lower body) are susceptible accidental impacts by ground service equipment (GSE). The very high mass (over 10,000 kg) of GSE impact can involve high energy (over 1000 J) and thus can induce significant internal damage. Furthermore, the large contact area potentially involved with GSE impact can create significant internal delamination and fiber failure without leaving exterior-visible signs that any damage has occurred. The objectives of the research described herein are to: (1) conduct experimental investigation into the composite aircraft damage caused by GSE impact, (2) examine the small-scale failure modes in focused, element-level studies, (3) establish a finite element modeling methodology involving detailed simulation capability that is validated via small-scale tests, and (4) apply these modeling capabilities to accurately predict full-scale structural behavior without adjustment (e.g., tuning) of modeling input parameters.

  3. NDE of hidden flaws in aging aircraft structures using obliquely backscattered ultrasonic signals (OBUS)

    NASA Astrophysics Data System (ADS)

    Bar-Cohen, Yoseph; Mal, Ajit K.; Lasser, Marvin E.

    1999-01-01

    Corrosion is a relatively slow material degradation process to which metallic structures of aircraft are subjected during service and it can appear in many forms. Generally, corrosion protection for preventing or inhibiting the formation and growth of corrosion damage on aircraft structures is well-established technology. Unfortunately, despite preventive measures, corrosion does occur and its probability of formation significantly increases as structures age. Corrosion detection and characterization at the initiation stages, while hidden under paint or in concealed areas, still poses a challenge to inspection science and technology. Corrosion damage is costly and it carries the risk of loss of life as well as hardware in case of catastrophic failure. The authors are investigating the application of obliquely backscattered ultrasonic signals (OBUS) as a means of detecting and characterizing corrosion under paint in metallic panels. OBUS were measured using oblique insonification and were used to produce C-scan images of corrosion damage located on both top and bottom faces of test panels through the paint. A combination of OBUS data and a sensor-array real-time imaging (SARTI) system is being developed for field applications. SARTI uses CCD to display ultrasonic data nd the integrated system has the potential to reduce the need for paint stripping prior to inspection. The main features of the combined OBUS and SARTI are described in this paper.

  4. Optimization applications in aircraft engine design and test

    NASA Technical Reports Server (NTRS)

    Pratt, T. K.

    1984-01-01

    Starting with the NASA-sponsored STAEBL program, optimization methods based primarily upon the versatile program COPES/CONMIN were introduced over the past few years to a broad spectrum of engineering problems in structural optimization, engine design, engine test, and more recently, manufacturing processes. By automating design and testing processes, many repetitive and costly trade-off studies have been replaced by optimization procedures. Rather than taking engineers and designers out of the loop, optimization has, in fact, put them more in control by providing sophisticated search techniques. The ultimate decision whether to accept or reject an optimal feasible design still rests with the analyst. Feedback obtained from this decision process has been invaluable since it can be incorporated into the optimization procedure to make it more intelligent. On several occasions, optimization procedures have produced novel designs, such as the nonsymmetric placement of rotor case stiffener rings, not anticipated by engineering designers. In another case, a particularly difficult resonance contraint could not be satisfied using hand iterations for a compressor blade, when the STAEBL program was applied to the problem, a feasible solution was obtained in just two iterations.

  5. Interactive computer graphics system for structural sizing and analysis of aircraft structures

    NASA Technical Reports Server (NTRS)

    Bendavid, D.; Pipano, A.; Raibstein, A.; Somekh, E.

    1975-01-01

    A computerized system for preliminary sizing and analysis of aircraft wing and fuselage structures was described. The system is based upon repeated application of analytical program modules, which are interactively interfaced and sequence-controlled during the iterative design process with the aid of design-oriented graphics software modules. The entire process is initiated and controlled via low-cost interactive graphics terminals driven by a remote computer in a time-sharing mode.

  6. Dynamic stability testing of aircraft - Needs versus capabilities

    NASA Technical Reports Server (NTRS)

    Orlik-Rueckemann, K. J.

    1973-01-01

    Highlights of a recent survey of the future needs for dynamic stability information for such aerospace vehicles as the Space Shuttle and advanced high-performance military aircraft, indicating the importance of obtaining this information for high-angle-of-attack high-Reynolds-number conditions. A review of the wind-tunnel capabilities in North America for measuring dynamic stability derivatives reveals an almost total lack of such capabilities for Mach numbers above 0.1 at angles of attack higher than 25 deg. In addition, capabilities to obtain certain new cross-coupling derivatives and information on effects of the coning motion are almost completely lacking. Recommendations are made regarding equipment that should be constructed to remedy this situation.

  7. Relative toxicity testing of spacecraft materials. 2: Aircraft materials

    NASA Technical Reports Server (NTRS)

    Lawrence, W. H.

    1980-01-01

    The relative toxicity of thermodegradation (pyrolysis/combustion) products of aircraft materials was studied. Two approaches were taken to assess the biological activity of the pyrolysis/combustion products of these materials: (1) determine the acute lethality to rats from inhalation of these pyrolysates and (2) examine the tendency for sublethal exposure to the pyrolysates to disrupt behavioral (shock avoidance) performance of exposed rats. The ralative importance of lethality vs. behavioral effects in selection of a material may be dictated by whether or not individuals potentially exposed to such products, would have an opportunity to escape if they were behaviorally capable of doing so. If so, the second parameter would assume greater importance, but if not the first parameter may be of much greater importance in selecting materials.

  8. Aircraft control surface failure detection and isolation using the OSGLR test. [orthogonal series generalized likelihood ratio

    NASA Technical Reports Server (NTRS)

    Bonnice, W. F.; Motyka, P.; Wagner, E.; Hall, S. R.

    1986-01-01

    The performance of the orthogonal series generalized likelihood ratio (OSGLR) test in detecting and isolating commercial aircraft control surface and actuator failures is evaluated. A modification to incorporate age-weighting which significantly reduces the sensitivity of the algorithm to modeling errors is presented. The steady-state implementation of the algorithm based on a single linear model valid for a cruise flight condition is tested using a nonlinear aircraft simulation. A number of off-nominal no-failure flight conditions including maneuvers, nonzero flap deflections, different turbulence levels and steady winds were tested. Based on the no-failure decision functions produced by off-nominal flight conditions, the failure detection and isolation performance at the nominal flight condition was determined. The extension of the algorithm to a wider flight envelope by scheduling on dynamic pressure and flap deflection is examined. Based on this testing, the OSGLR algorithm should be capable of detecting control surface failures that would affect the safe operation of a commercial aircraft. Isolation may be difficult if there are several surfaces which produce similar effects on the aircraft. Extending the algorithm over the entire operating envelope of a commercial aircraft appears feasible.

  9. Real-time flight test analysis and display techniques for the X-29A aircraft

    NASA Technical Reports Server (NTRS)

    Hicks, John W.; Petersen, Kevin L.

    1988-01-01

    The X-29A advanced technology demonstrator flight envelope expansion program and the subsequent flight research phase gave impetus to the development of several innovative real-time analysis and display techniques. These new techniques produced significant improvements in flight test productivity, flight research capabilities, and flight safety. These techniques include real-time measurement and display of in-flight structural loads, dynamic structural mode frequency and damping, flight control system dynamic stability and control response, aeroperformance drag polars, and aircraft specific excess power. Several of these analysis techniques also provided for direct comparisons of flight-measured results with analytical predictions. The aeroperformance technique was made possible by the concurrent development of a new simplified in-flight net thrust computation method. To achieve these levels of on-line flight test analysis, integration of ground and airborne systems was required. The capability of NASA Ames Research Center, Dryden Flight Research Facility's Western Aeronautical Test Range was a key factor in enabling implementation of these methods.

  10. Service evaluation of aluminum-brazed titanium (ABTi). [aircraft structures

    NASA Technical Reports Server (NTRS)

    Elrod, S. D.

    1981-01-01

    Long term creep-rupture, flight service and jet engine exhaust tests on aluminum-brazed titanium (ABTi), originally initiated under the DOT/SST follow-on program, were completed. These tests included exposure to natural airline service environments for up to 6 years. The results showed that ABTi has adequate corrosion resistance for long time commercial airplane structural applications. Special precautions are required for those sandwich structures designed for sound attenuation that utilize perforated skins. ABTi was also shown to have usable creep-rupture strength and to be metallurgically stable at temperatures up to 425 C (800 F).

  11. Proceedings of the Symposium on Welding, Bonding, and Fastening. [production engineering for aircraft and spacecraft structures

    NASA Technical Reports Server (NTRS)

    Stein, B. A. (Compiler); Buckley, J. D. (Compiler)

    1972-01-01

    Various technological processes to achieve lightweight reliable joining systems for structural elements of aircraft and spacecraft are considered. Joining methods, combinations of them, and nondestructive evaluation and quality assurance are emphasized.

  12. Distributed ice accretion sensor for smart aircraft structures

    NASA Technical Reports Server (NTRS)

    Gerardi, J. J.; Hickman, G. A.

    1989-01-01

    A distributed ice accretion sensor is presented, based on the concept of smart structures. Ice accretion is determined using spectral techniques to process signals from piezoelectric sensors integral to the airfoil skin. Frequency shifts in the leading edge structural skin modes are correlated to ice thickness. It is suggested that this method may be used to detect ice over large areas with minimal hardware. Results are presented from preliminary tests to measure simulated ice growth.

  13. Aeroelasticity of Axially Loaded Aerodynamic Structures for Truss-Braced Wing Aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, Nhan; Ting, Eric; Lebofsky, Sonia

    2015-01-01

    This paper presents an aeroelastic finite-element formulation for axially loaded aerodynamic structures. The presence of axial loading causes the bending and torsional sitffnesses to change. For aircraft with axially loaded structures such as the truss-braced wing aircraft, the aeroelastic behaviors of such structures are nonlinear and depend on the aerodynamic loading exerted on these structures. Under axial strain, a tensile force is created which can influence the stiffness of the overall aircraft structure. This tension stiffening is a geometric nonlinear effect that needs to be captured in aeroelastic analyses to better understand the behaviors of these types of aircraft structures. A frequency analysis of a rotating blade structure is performed to demonstrate the analytical method. A flutter analysis of a truss-braced wing aircraft is performed to analyze the effect of geometric nonlinear effect of tension stiffening on the flutter speed. The results show that the geometric nonlinear tension stiffening effect can have a significant impact on the flutter speed prediction. In general, increased wing loading results in an increase in the flutter speed. The study illustrates the importance of accounting for the geometric nonlinear tension stiffening effect in analyzing the truss-braced wing aircraft.

  14. Applications of structural optimization methods to fixed-wing aircraft and spacecraft in the 1980s

    NASA Technical Reports Server (NTRS)

    Miura, Hirokazu; Neill, Douglas J.

    1992-01-01

    This report is the summary of a technical survey on the applications of structural optimization in the U.S. aerospace industry through the 1980s. Since applications to rotary wing aircraft will be covered by other literature, applications to fixed-wing aircraft and spacecraft were considered. It became clear that very significant progress has been made during this decade, indicating this technology is about to become one of the practical tools in computer aided structural design.

  15. Full-scale aircraft cabin flammability tests of improved fire-resistant materials

    NASA Technical Reports Server (NTRS)

    Stuckey, R. N.; Surpkis, D. E.; Price, L. J.

    1974-01-01

    Full-scale aircraft cabin flammability tests to evaluate the effectiveness of new fire-resistant materials by comparing their burning characteristics with those of older aircraft materials are described. Three tests were conducted and are detailed. Test 1, using pre-1968 materials, was run to correlate the procedures and to compare the results with previous tests by other organizations. Test 2 included newer, improved fire-resistant materials. Test 3 was essentially a duplicate of test 2, but a smokeless fuel was used. Test objectives, methods, materials, and results are presented and discussed. Results indicate that the pre-1968 materials ignited easily, allowed the fire to spread, produced large amounts of smoke and toxic combustion products, and resulted in a flash fire and major fire damage. The newer fire-resistant materials did not allow the fire to spread. Furthermore, they produced less, lower concentrations of toxic combustion products, and lower temperatures. The newer materials did not produce a flash fire.

  16. Preliminary tests of vulnerability of typical aircraft electronics to lightning-induced voltages

    NASA Technical Reports Server (NTRS)

    Plumer, J. A.; Walko, L. C.

    1974-01-01

    Tests made on two pieces of typical aircraft electronics equipment to ascertain their vulnerability to simulated lightning-induced transient voltages representative of those which might occur in flight when the aircraft is struck by lightning were conducted. The test results demonstrated that such equipment can be interfered with or damaged by transient voltages as low as 21 volts peak. Greater voltages can cause failure of semiconductor components within the equipment. The results emphasize a need for establishment of coordinated system susceptibility and component vulnerability criteria to achieve lightning protection of aerospace electrical and electronic systems.

  17. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    NASA Technical Reports Server (NTRS)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  18. DCS-Neural-Network Program for Aircraft Control and Testing

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C.

    2006-01-01

    A computer program implements a dynamic-cell-structure (DCS) artificial neural network that can perform such tasks as learning selected aerodynamic characteristics of an airplane from wind-tunnel test data and computing real-time stability and control derivatives of the airplane for use in feedback linearized control. A DCS neural network is one of several types of neural networks that can incorporate additional nodes in order to rapidly learn increasingly complex relationships between inputs and outputs. In the DCS neural network implemented by the present program, the insertion of nodes is based on accumulated error. A competitive Hebbian learning rule (a supervised-learning rule in which connection weights are adjusted to minimize differences between actual and desired outputs for training examples) is used. A Kohonen-style learning rule (derived from a relatively simple training algorithm, implements a Delaunay triangulation layout of neurons) is used to adjust node positions during training. Neighborhood topology determines which nodes are used to estimate new values. The network learns, starting with two nodes, and adds new nodes sequentially in locations chosen to maximize reductions in global error. At any given time during learning, the error becomes homogeneously distributed over all nodes.

  19. Piloted Simulation Assessment of the Impact of Flexible Structures on Handling Qualities of Generic Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Stringer, Mary T.; Cowen, Brandon; Hoffler, Keith D.; Couch, Jesse C.; Ogburn, Marilyn E.; Diebler, Corey G.

    2013-01-01

    The NASA Langley Research Center Cockpit Motion Facility (CMF) was used to conduct a piloted simulation assessment of the impact of flexible structures on flying qualities. The CMF was used because of its relatively high bandwidth, six degree-of-freedom motion capability. Previous studies assessed and attempted to mitigate the effects of multiple dynamic aeroservoelastic modes (DASE). Those results indicated problems existed, but the specific cause and effect was difficult to ascertain. The goal of this study was to identify specific DASE frequencies, damping ratios, and gains that cause degradation in handling qualities. A generic aircraft simulation was developed and designed to have Cooper-Harper Level 1 handling qualities when flown without DASE models. A test matrix of thirty-six DASE modes was implemented. The modes had frequencies ranging from 1 to 3.5 Hz and were applied to each axis independently. Each mode consisted of a single axis, frequency, damping, and gain, and was evaluated individually by six subject pilots with test pilot backgrounds. Analysis completed to date suggests that a number of the DASE models evaluated degrade the handling qualities of this class of aircraft to an uncontrollable condition.

  20. Concepts for improving the damage tolerance of composite compression panels. [aircraft structures

    NASA Technical Reports Server (NTRS)

    Rhodes, M. D.; Williams, J. G.

    1984-01-01

    The residual strength of specimens with damage and the sensitivity to damage while subjected to an applied inplane compression load were determined for flatplate specimens and blade-stiffened panels. The results suggest that matrix materials that fail by delamination have the lowest damage tolerance capability. Alternate matrix materials or laminates which are transversely reinforced suppress the delamination mode of failure and change the failure mode to transverse shear crippling which occurs at a higher strain value. Several damage-tolerant blade-stiffened panel design concepts are evaluated. Structural efficiency studies conducted show only small mass penalties may result from incorporating these damage-tolerant features in panel design. The implication of test results on the design of aircraft structures was examined with respect to FAR requirements.

  1. Instrumentation and data acquisition for full-scale aircraft crash testing

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Fasanella, Edwin L.

    1993-01-01

    The Landing and Impact Dynamics Branch of the NASA Langley Research Center has been conducting full-scale aircraft crash tests since the 1970s. Using a pendulum method, aircraft are suspended by cables from a 240-ft high gantry and swung into the impact surface at various attitudes and velocities. Instrumentation for these tests include on-board high-speed cameras, strain gages, load cells, displacement transducers, and accelerometers. Transducers in the aircraft are hard-wired through a long umbilical cable to the data acquisition room. Up to 96 channels of data can be collected at a typical rate of 4000 samples per second. Data acquisition using an FM multiplexed analog system and a high-speed personal computer based digital system is described.

  2. An investigation of scale model testing of VTOL aircraft in hover

    NASA Technical Reports Server (NTRS)

    Hill, W. G., Jr.; Jenkins, R. C.; Dudley, M. R.

    1982-01-01

    Utilizing the unique opportunity created by full scale hover testing of the twin-jet Grumman Design 698 VTOL aircraft in the NASA-Ames Hover Facility, a series of experiments was conducted to evaluate the effectivness of scale model testing in predicting full scale behavior. Interference forces were found to be sensitive to aircraft lower surface geometry, but when the geometry was modeled accurately the small scale results matched full scale forces guite well. The interference forces were found to be insensitive to core nozzle temperature and fan nozzle pressure ratio. The results clearly demonstrate that small scale models can be reliably utilized for aircraft and technology development when the appropriate sensitivities are recognized.

  3. Air Force use of civil airworthiness criteria for testing and acceptance of military derivative transport aircraft

    SciTech Connect

    Marx, R.I.; Chapman, D.M.; Langley, M.J.; Fouts, R.S.

    1990-01-01

    A review of commercial aircraft programs and the use of FAA certification criteria in the acquisition of off-the-shelf transport aircraft by the USAF to fulfill its airlift requirements is presented. In addition, major differences between military and commercial test programs and acquisition are cited to illustrate the principal benefits to the Air Force of this method. Significantly reduced acquisition time, and reduced ground and flight testing and development costs are shown as benefits of this process. The unique aspects of certification of military derivatives, recent initiatives to codify the processes, and the impacts on changes required in the manner in which the USAF currently contracts for aircraft are discussed. 20 refs.

  4. X-36 Tailless Fighter Agility Research Aircraft on lakebed during high-speed taxi tests

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA/McDonnell Douglas Corporation (MDC) X-36 Tailless Fighter Agility Research Aircraft undergoes high-speed taxi tests on Rogers Dry Lake at NASA Dryden Flight Research Center, Edwards, California, on October 17, 1996. The aircraft was tested at speeds up to 85 knots. Normal takeoff speed would be 110 knots. More taxi and radio frequency tests were slated before it's first flight would be made. This took place on May 17, 1997. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems

  5. Durability and damage tolerance of Large Composite Primary Aircraft Structure (LCPAS)

    NASA Technical Reports Server (NTRS)

    Mccarty, John E.; Roeseler, William G.

    1984-01-01

    Analysis and testing addressing the key technology areas of durability and damage tolerance were completed for wing surface panels. The wing of a fuel-efficient, 200-passenger commercial transport airplane for 1990 delivery was sized using graphite-epoxy materials. Coupons of various layups used in the wing sizing were tested in tension, compression, and spectrum fatigue with typical fastener penetrations. The compression strength after barely visible impact damage was determined from coupon and structural element tests. One current material system and one toughened system were evaluated by coupon testing. The results of the coupon and element tests were used to design three distinctly different compression panels meeting the strength, stiffness, and damage-tolerance requirements of the upper wing panels. These three concepts were tested with various amounts of damage ranging from barely visible impact to through-penetration. The results of this program provide the key technology data required to assess the durability and damage-tolerance capability or advanced composites for use in commercial aircraft wing panel structure.

  6. Current and Future Research in Active Control of Lightweight, Flexible Structures Using the X-56 Aircraft

    NASA Technical Reports Server (NTRS)

    Ryan, John J.; Bosworth, John T.; Burken, John J.; Suh, Peter M.

    2014-01-01

    The X-56 Multi-Utility Technology Testbed aircraft system is a versatile experimental research flight platform. The system was primarily designed to investigate active control of lightweight flexible structures, but is reconfigurable and capable of hosting a wide breadth of research. Current research includes flight experimentation of a Lockheed Martin designed active control flutter suppression system. Future research plans continue experimentation with alternative control systems, explore the use of novel sensor systems, and experiments with the use of novel control effectors. This paper describes the aircraft system, current research efforts designed around the system, and future planned research efforts that will be hosted on the aircraft system.

  7. Flight testing the fixed-wing configuration of the Rotor Systems Research Aircraft (RSRA)

    NASA Technical Reports Server (NTRS)

    Hall, G. W.; Morris, P. M.

    1985-01-01

    The Rotor Systems Research Aircraft (RSRA) is a unique research aircraft designed to flight test advanced helicopter rotor system. Its principal flight test configuration is as a compound helicopter. The fixed wing configuration of the RSRA was primarily considered an energy fly-home mode in the event it became necessary to sever an unstable rotor system in flight. While it had always been planned to flight test the fixed wing configuration, the selection of the RSRA as the flight test bed for the X-wing rotor accelerated this schedule. This paper discusses the build-up to, and the test of, the RSRA fixed wing configuration. It is written primarily from the test pilot's perspective.

  8. CV-990 Landing Systems Research Aircraft (LSRA) during final Space Shuttle tire test

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A Convair 990 (CV-990) was used as a Landing Systems Research Aircraft (LSRA) at NASA's Dryden Flight Research Center, Edwards, California, to test space shuttle landing gear and braking systems as part of NASA's effort to upgrade and improve space shuttle capabilities. The first flight at Dryden of the CV-990 with shuttle test components occurred in April 1993, and tests continued into August 1995, when this photo shows a test of the shuttle tires. The purpose of this series of tests was to determine the performance parameters and failure limits of the tires. This particular landing was on the dry lakebed at Edwards, but other tests occurred on the main runway there. The CV-990, built in 1962 by the Convair Division of General Dynamics Corp., Ft. Worth, Texas, served as a research aircraft at Ames Research Center, Moffett Field, California, before it came to Dryden.

  9. YF-12 Lockalloy ventral fin program, volume 1. [design analysis, fabrication, and manufacturing of aircraft structures using aluminum and beryllium alloys for the lockheed YF-12 aircraft

    NASA Technical Reports Server (NTRS)

    Duba, R. J.; Haramis, A. C.; Marks, R. F.; Payne, L.; Sessing, R. C.

    1976-01-01

    Results are presented of the YF-12 Lockalloy Ventral Fin Program which was carried out by Lockheed Aircraft Corporation - Advanced Development Projects for the joint NASA/USAF YF-12 Project. The primary purpose of the program was to redesign and fabricate the ventral fin of the YF-12 research airplane (to reduce flutter) using Lockalloy, and alloy of beryllium and aluminum, as a major structural material. A secondary purpose, was to make a material characterization study (thermodynamic properties, corrosion; fatigue tests, mechanical properties) of Lockalloy to validate the design of the ventral fin and expand the existing data base on this material. All significant information pertinent to the design and fabrication of the ventral fin is covered. Emphasis throughout is given to Lockalloy fabrication and machining techniques and attendant personnel safety precautions. Costs are also examined. Photographs of tested alloy specimens are shown along with the test equipment used.

  10. X-36 Tailless Fighter Agility Research Aircraft on lakebed during high-speed taxi tests

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA/McDonnell Douglas Corporation (MDC) X-36 Tailless Fighter Agility Research Aircraft undergoes high-speed taxi tests on Rogers Dry Lake at NASA Dryden Flight Research Center, Edwards, California, on October 17, 1996. The aircraft was tested at speeds up to 85 knots. Normal takeoff speed would be 110 knots. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems and the risks associated with their inability to deal with unknown or unforeseen phenomena in flight. Fully fueled the X

  11. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure

    NASA Technical Reports Server (NTRS)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter

    2014-01-01

    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  12. NASA Hybrid Wing Aircraft Aeroacoustic Test Documentation Report

    NASA Technical Reports Server (NTRS)

    Heath, Stephanie L.; Brooks, Thomas F.; Hutcheson, Florence V.; Doty, Michael J.; Bahr, Christopher J.; Hoad, Danny; Becker, Lawrence; Humphreys, William M.; Burley, Casey L.; Stead, Dan; Pope, Dennis S.; Spalt, Taylor B.; Kuchta, Dennis H.; Plassman, Gerald E.; Moen, Jaye A.

    2016-01-01

    This report summarizes results of the Hybrid Wing Body (HWB) N2A-EXTE model aeroacoustic test. The N2A-EXTE model was tested in the NASA Langley 14- by 22-Foot Subsonic Tunnel (14x22 Tunnel) from September 12, 2012 until January 28, 2013 and was designated as test T598. This document contains the following main sections: Section 1 - Introduction, Section 2 - Main Personnel, Section 3 - Test Equipment, Section 4 - Data Acquisition Systems, Section 5 - Instrumentation and Calibration, Section 6 - Test Matrix, Section 7 - Data Processing, and Section 8 - Summary. Due to the amount of material to be documented, this HWB test documentation report does not cover analysis of acquired data, which is to be presented separately by the principal investigators. Also, no attempt was made to include preliminary risk reduction tests (such as Broadband Engine Noise Simulator and Compact Jet Engine Simulator characterization tests, shielding measurement technique studies, and speaker calibration method studies), which were performed in support of this HWB test. Separate reports containing these preliminary tests are referenced where applicable.

  13. Proceedings of the FAA-NASA Symposium on the Continued Airworthiness of Aircraft Structures. Volume 1

    NASA Technical Reports Server (NTRS)

    Bigelow, Catherine A. (Compiler)

    1997-01-01

    This publication contains the fifty-two technical papers presented at the FAA-NASA Symposium on the Continued Airworthiness of Aircraft Structures. The symposium, hosted by the FAA Center of Excellence for Computational Modeling of Aircraft Structures at Georgia Institute of Technology, was held to disseminate information on recent developments in advanced technologies to extend the life of high-time aircraft and design longer-life aircraft. Affiliations of the participants included 33% from government agencies and laboratories, 19% from academia, and 48% from industry; in all 240 people were in attendance. Technical papers were selected for presentation at the symposium, after a review of extended abstracts received by the Organizing Committee from a general call for papers.

  14. Proceedings of the FAA-NASA Symposium on the Continued Airworthiness of Aircraft Structures. Volume 2

    NASA Technical Reports Server (NTRS)

    Bigelow, Catherine A. (Compiler)

    1997-01-01

    This publication contains the fifty-two technical papers presented at the FAA-NASA Symposium on the Continued Airworthiness of Aircraft Structures. The symposium, hosted by the FAA Center of Excellence for Computational Modeling of Aircraft Structures at Georgia Institute of Technology, was held to disseminate information on recent developments in advanced technologies to extend the life of high-time aircraft and design longer-life aircraft. Affiliations of the participants included 33% from government agencies and laboratories, 19% from academia, and 48% from industry; in all 240 people were in attendance. Technical papers were selected for presentation at the symposium, after a review of extended abstracts received by the Organizing Committee from a general call for papers.

  15. NASA rotor system research aircraft flight-test data report: Helicopter and compound configuration

    NASA Technical Reports Server (NTRS)

    Erickson, R. E.; Kufeld, R. M.; Cross, J. L.; Hodge, R. W.; Ericson, W. F.; Carter, R. D. G.

    1984-01-01

    The flight test activities of the Rotor System Research Aircraft (RSRA), NASA 740, from June 30, 1981 to August 5, 1982 are reported. Tests were conducted in both the helicopter and compound configurations. Compound tests reconfirmed the Sikorsky flight envelope except that main rotor blade bending loads reached endurance at a speed about 10 knots lower than previously. Wing incidence changes were made from 0 to 10 deg.

  16. Evaluation of new spectral bands for multi-spectral imaging: SMIRR aircraft test results

    USGS Publications Warehouse

    Goetz, Alexander F.H.; Rowan, Lawrence C.

    1980-01-01

    A 10-channel radiometer called the Shuttle Multispectral Infrared Radiometer (SMIRR) is scheduled to take data from orbit on the second shuttle orbital light test. As part of the instrument test sequence, a series of aircraft flights was carried out over 10 test areas in Utah and Nevada. Apart from vegetation, the materials exposed at the surface were volcanic sequences ranging from tuffs to basalts, areas of hydrothermally altered volcanic rocks, sedimentary sequences of sandstone and carbonate rocks, and alluvial cover.

  17. Real-time testing of titanium sheet and extrusion coupon specimens subjected to Mach 2.7 supersonic cruise aircraft wing stresses and temperatures

    NASA Technical Reports Server (NTRS)

    Lunde, T.

    1977-01-01

    The accuracy of three accelerated flight-by-flight test methods for material selection, and fatigue substantiation of supersonic cruise aircraft structure was studied. The real time stresses and temperatures applied to the specimens were representative of the service conditions in the lower surface of a Mach 2.7 supersonic cruise aircraft wing root structure. Each real time flight lasted about 65 minutes, including about one hour at (500 F) in the cruise condition. Center notched coupon specimens from six titanium materials were tested: mill-annealed, duplex-annealed, and triplex-annealed Ti-8Al-1Mo-1V sheets; mill-annealed Ti-8Al-1Mo-1V extrusion; mill-annealed Ti-6Al-4V sheet; and solution-treated and aged Ti-6Al-4V extrusion. For duplex-annealed Ti-8Al-1Mo-1V sheet, specimens with single spotweld were also tested. The test results were studied in conjunction with other related data from the literature for: material selection, structural fabrication, fatigue resistance of supersonic cruise aircraft structure, and fatigue test acceleration procedures for supersonic cruise aircraft.

  18. CID-720 aircraft Langley Research Center preflight hardware tests: Development, flight acceptance and qualification

    NASA Technical Reports Server (NTRS)

    Pride, J. D.

    1986-01-01

    The testing conducted on LaRC-developed hardware for the controlled impact demonstration transport aircraft is discussed. To properly develop flight qualified crash systems, two environments were considered: the aircraft flight environment with the focus on vibration and temperature effects, and the crash environment with the long pulse shock effects. Also with the large quantity of fuel in the wing tanks the possibility of fire was considered to be a threat to data retrieval and thus fire tests were included in the development test process. The aircraft test successfully demonstrated the performance of the LaRC developed heat shields. Good telemetered data (S-band) was received during the impact and slide-out phase, and even after the aircraft came to rest. The two onboard DAS tape recorders were protected from the intense fire and high quality tape data was recovered. The complete photographic system performed as planned throughout the 40.0 sec of film supply. The four photo power distribution pallets remained in good condition and all ten onboard 16 mm high speed (400 frames/sec) cameras produced good film data.

  19. Design study of test models of maneuvering aircraft configurations for the National Transonic Facility (NTF)

    NASA Technical Reports Server (NTRS)

    Griffin, S. A.; Madsen, A. P.; Mcclain, A. A.

    1984-01-01

    The feasibility of designing advanced technology, highly maneuverable, fighter aircraft models to achieve full scale Reynolds number in the National Transonic Facility (NTF) is examined. Each of the selected configurations are tested for aeroelastic effects through the use of force and pressure data. A review of materials and material processes is also included.

  20. A unique facility for V/STOL aircraft hover testing. [Langley Impact Dynamics Research Facility

    NASA Technical Reports Server (NTRS)

    Culpepper, R. G.; Murphy, R. D.; Gillespie, E. A.; Lane, A. G.

    1979-01-01

    The Langley Impact Dynamics Research Facility (IDRF) was modified to obtain static force and moment data and to allow assessment of aircraft handling qualities during dynamic tethered hover flight. Test probe procedures were also established. Static lift and control measurements obtained are presented along with results of limited dynamic tethered hover flight.

  1. Description and Laboratory Tests of a Roots Type Aircraft Engine Supercharger

    NASA Technical Reports Server (NTRS)

    Ware, Marsden

    1926-01-01

    This report describes a roots type aircraft engine supercharger and presents the results of some tests made with it at the Langley Field Laboratories of the National Advisory Committee for Aeronautics. The supercharger used in these tests was constructed largely of aluminum, weighed 88 pounds and was arranged to be operated from the rear of a standard aircraft engine at a speed of 1 1/2 engine crankshaft speed. The rotors of the supercharger were cycloidal in form and were 11 inches long and 9 1/2 inches in diameter. The displacement of the supercharger was 0.51 cubic feet of air per revolution of the rotors. The supercharger was tested in the laboratory, independently and in combination with a Liberty-12 aircraft engine, under simulated altitude pressure conditions in order to obtain information on its operation and performance. From these tests it seems evident that the Roots blower compares favorably with other compressor types used as aircraft engine superchargers and that it has several features that make it particularly attractive for such use.

  2. Role of structural noise in aircraft pressure cockpit from vibration action of new-generation engines

    NASA Astrophysics Data System (ADS)

    Baklanov, V. S.

    2016-07-01

    The evolution of new-generation aircraft engines is transitioning from a bypass ratio of 4-6 to an increased ratio of 8-12. This is leading to substantial broadening of the vibration spectrum of engines with a shift to the low-frequency range due to decreased rotation speed of the fan rotor, in turn requiring new solutions to decrease structural noise from engine vibrations to ensure comfort in the cockpits and cabins of aircraft.

  3. Changes in structural health monitoring system capability due to aircraft environmental factors

    NASA Astrophysics Data System (ADS)

    Kuhn, Jeffrey D.

    Structural Health Monitoring (SHM) promises to decrease the maintenance cost and increase the availability of aging aircraft fleets by fundamentally changing the way structural inspections are performed. But this promise can only be realized through the consistent and predictable performance of a SHM system throughout the entire remaining life of an aircraft. In a sensor-based SHM system, sensor signal changes are analyzed and interpreted to identify structural flaws. But aircraft environmental factors such as temperature fluctuations, cyclic strain and exposure to various aircraft fluids also have the potential to change SHM sensor signals, raising questions about long term SHM system capability. This research begins by analyzing the current USAF inspection paradigm, known aircraft environmental factors, representative structural inspection locations for the F-15 and C-130, and current SHM technologies. A design of experiments approach is used to build and execute an experiment to determine the effect of one aircraft environmental factor (cyclic strain) on a common SHM technology (PZT-based sensors). Analysis of the experimental results shows the sensors to be significantly affected by cyclic strain, and that the effects can be estimated using a power equation model. A "probability of detection (POD) degradation model" is then developed by extending existing nondestructive evaluation (NDE) POD analysis techniques. This model demonstrates how changes in sensor performance due to an aircraft environmental factor can be used to estimate the change in overall performance of the SHM system. This POD degradation model provides a common framework to predict changes in SHM system performance over the remaining life of an aircraft. An example combining the experimental results with an existing SHM POD analysis shows how the POD degradation model can be applied to current SHM research.

  4. Crash Testing and Simulation of a Cessna 172 Aircraft: Pitch Down Impact Onto Soft Soil

    NASA Technical Reports Server (NTRS)

    Fasanella, Edwin L.; Jackson, Karen E.

    2016-01-01

    During the summer of 2015, NASA Langley Research Center conducted three full-scale crash tests of Cessna 172 (C-172) aircraft at the NASA Langley Landing and Impact Research (LandIR) Facility. The first test represented a flare-to-stall emergency or hard landing onto a rigid surface. The second test, which is the focus of this paper, represented a controlled-flight-into-terrain (CFIT) with a nose-down pitch attitude of the aircraft, which impacted onto soft soil. The third test, also conducted onto soil, represented a CFIT with a nose-up pitch attitude of the aircraft, which resulted in a tail strike condition. These three crash tests were performed for the purpose of evaluating the performance of Emergency Locator Transmitters (ELTs) and to generate impact test data for model validation. LS-DYNA finite element models were generated to simulate the three test conditions. This paper describes the model development and presents test-analysis comparisons of acceleration and velocity time-histories, as well as a comparison of the time sequence of events for Test 2 onto soft soil.

  5. New airfoil sections for general aviation aircraft. [cruising and flap development tests

    NASA Technical Reports Server (NTRS)

    Wentz, W. H., Jr.

    1973-01-01

    A program has been undertaken to develop new airfoil sections suitable for general aviation aircraft, utilizing theoretical and experimental advanced technology developed in recent years primarily for subsonic jet transport and military aircraft. The airfoil development program is one component of the Advanced Technology Light Twin program sponsored by NASA Langley Research Center. Two-dimensional tests of a new airfoil have demonstrated high cruising performance over a fairly wide C sub 1 range, and a C sub 1 max value of 3.69 with Fowler flap and no leading-edge devices. Experimental and theoretical development of additional configurations is under way.

  6. Application of fiber-reinforced bismaleimide materials to aircraft nacelle structures

    NASA Technical Reports Server (NTRS)

    Peros, Vasilios; Ruth, John; Trawinski, David

    1992-01-01

    Existing aircraft engine nacelle structures employ advanced composite materials to reduce weight and thereby increase overall performance. Use of advanced composite materials on existing aircraft nacelle structures includes fiber-reinforced epoxy structures and has typically been limited to regions furthest away from the hot engine core. Portions of the nacelle structure that are closer to the engine require materials with a higher temperature capability. In these portions, existing nacelle structures employ aluminum sandwich construction and skin/stringer construction. The aluminum structure is composed of many detail parts and assemblies and is usually protected by some form of ablative, insulator, or metallic thermal shield. A one-piece composite inner cowl for a new-generation engine nacelle structure has been designed using fiber-reinforced bismaleimide (BMI) materials and honeycomb core in a sandwich construction. The new composite design has many advantages over the existing aluminum structure. Multiple details were integrated into the one-piece composite design, thereby significantly reducing the number of detail parts and fasteners. The use of lightweight materials and the reduction of the number of joints result in a significant weight reduction over the aluminum design; manufacturing labor and the overall number of tools required have also been reduced. Several significant technical issues were addressed in the development of a BMI composite design. Technical evaluation of the available BMI systems led to the selection of a toughened BMI material which was resistant to microcracking under thermal cyclic loading and enhanced the damage tolerance of the structure. Technical evaluation of the degradation of BMI materials in contact with aluminum and other metals validated methods for isolation of the various materials. Graphite-reinforced BMI in contact with aluminum and some steels was found to degrade in salt spray testing. Isolation techniques such as

  7. Static noise tests on augmentor wing jet STOL research aircraft (C8A Buffalo)

    NASA Technical Reports Server (NTRS)

    Marrs, C. C.; Harkonen, D. L.; Okeefe, J. V.

    1974-01-01

    Results are presented for full scale ground static acoustic tests of over-area conical nozzles and a lobe nozzle installed on the Augmentor Wing Jet STOL Research Aircraft, a modified C8A Buffalo. The noise levels and spectrums of the test nozzles are compared against those of the standard conical nozzle now in use on the aircraft. Acoustic evaluations at 152 m (500 ft), 304 m (1000 ft), and 1216 m (4000 ft) are made at various engine power settings with the emphasis on approach and takeoff power. Appendix A contains the test log and propulsion calculations. Appendix B gives the original test plan, which was closely adhered to during the test. Appendix C describes the acoustic data recording and reduction systems, with calibration details.

  8. Active and passive structural design concepts for improved empennage effectiveness of aircraft

    NASA Astrophysics Data System (ADS)

    Weiss, Franz; Schweiger, Johannes; Simpson, John; Kullrich, Thomas

    2000-06-01

    Active structures concepts for the design of aircraft have been investigated for several years. Concerning static aeroelastic applications, all concepts known to the authors are trying to improve the design of aircraft wings. In the case of wings however, the design space for active structures concepts is limited by a multitude of functional requirements. Empennage surfaces on the other hand only have to meet two basic requirements: sufficient stability and maneuverability for the longitudinal and lateral motion of the aircraft. In the case of vertical tails, the aerodynamic effectiveness for the side force and for the rudder yawing moment are usually reduced by the flexibility of the structure. This causes a weight increase for the structure, which is especially unpleasant for tail surfaces because of the rearward shift of the center of gravity. Today, multidisciplinary structural optimization methods can be used to minimize the weight penalty for static aeroelastic effectiveness requirements. But an amount of penalty still remains. A smart solution for additional weight savings, if possible below the conventional basic strength design of the structure, would therefore be very welcome for any new aircraft design. The paper will describe a new design approach for vertical tails. The concept is based on a smart system for the attachment of the complete tail surface to the fuselage. If properly designed, the variable stiffness of this system will provide improved aerodynamic effectiveness of the tail at any flight condition compared to the rigid aircraft. In a first step, the structure for the vertical tail of a fighter aircraft is designed for static strength and buckling stability by means of a structural optimization program, which is based on finite element methods. The impacts of static aeroelastic effectiveness and flutter stability criteria on the structural design are shown. A modified structural model is then used to incorporate the active system for the

  9. Standard test method for corrosion of low-embrittling cadmium plate by aircraft maintenance chemicals. ASTM standard

    SciTech Connect

    1989-02-01

    This test method is under the jurisdiction of ASTM Committee F-7 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.07 on Qualification Testing of Aircraft Cleaning Materials. Current edition approved Nov. 17, 1988. Published February 1989 and reapproved 1998.

  10. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    NASA Astrophysics Data System (ADS)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  11. Structural testing for static failure, flutter and other scary things

    NASA Technical Reports Server (NTRS)

    Ricketts, R. H.

    1983-01-01

    Ground test and flight test methods are described that may be used to highlight potential structural problems that occur on aircraft. Primary interest is focused on light-weight general aviation airplanes. The structural problems described include static strength failure, aileron reversal, static divergence, and flutter. An example of each of the problems is discussed to illustrate how the data acquired during the tests may be used to predict the occurrence of the structural problem. While some rules of thumb for the prediction of structural problems are given the report is not intended to be used explicitly as a structural analysis handbook.

  12. Robust Damage-Mitigating Control of Aircraft for High Performance and Structural Durability

    NASA Technical Reports Server (NTRS)

    Caplin, Jeffrey; Ray, Asok; Joshi, Suresh M.

    1999-01-01

    This paper presents the concept and a design methodology for robust damage-mitigating control (DMC) of aircraft. The goal of DMC is to simultaneously achieve high performance and structural durability. The controller design procedure involves consideration of damage at critical points of the structure, as well as the performance requirements of the aircraft. An aeroelastic model of the wings has been formulated and is incorporated into a nonlinear rigid-body model of aircraft flight-dynamics. Robust damage-mitigating controllers are then designed using the H(infinity)-based structured singular value (mu) synthesis method based on a linearized model of the aircraft. In addition to penalizing the error between the ideal performance and the actual performance of the aircraft, frequency-dependent weights are placed on the strain amplitude at the root of each wing. Using each controller in turn, the control system is put through an identical sequence of maneuvers, and the resulting (varying amplitude cyclic) stress profiles are analyzed using a fatigue crack growth model that incorporates the effects of stress overload. Comparisons are made to determine the impact of different weights on the resulting fatigue crack damage in the wings. The results of simulation experiments show significant savings in fatigue life of the wings while retaining the dynamic performance of the aircraft.

  13. Vibration attenuation of aircraft structures utilizing active materials

    NASA Astrophysics Data System (ADS)

    Agnes, Gregory S.; Whitehouse, Stephen R.; Mackaman, John R.

    1993-09-01

    The need for active vibration control for airborne laser systems was demonstrated during the late 1970s by the Airborne Laser Laboratory. Other possible applications include sonic fatigue alleviation, reduction of buffet induced fatigue, vibration control for embedded antennae, and active aeroelastic control. The purpose of this paper is to present an overview of active vibration control technology and its application to aircraft. Classification of classic aircraft vibration problems and currently available solutions are used to provide a framework for the study. Current solutions are classified as being either passive or active and by the methodology (modal modification or addition) used to reduce vibration. Possible applications for this technology in aircraft vibration control are presented within this framework to demonstrate the increased versatility active materials technologies provide the designer. An in- depth study of an active pylon to reduce wing/store vibration is presented as an example. Finally, perceived gaps in the existing technology base are identified and both on-going and future research plans in these areas are discussed.

  14. A smart composite patch for the repair of aircraft structures

    NASA Astrophysics Data System (ADS)

    Wakha, Kelah; Samuel, Paul; Pines, Darryll J.

    2005-05-01

    Recent interest in bonded composite patch repair technology for aerospace systems is because this method can be carried out at a reduced cost and time and can easily be applied to complex geometric structures. This paper details the development of a dual stiffness/energy sensor for monitoring the integrity of a composite patch used to repair an aluminum structural component. The smart sensor has the ability to predict the elastic field of a given host structure based on the strain state of two sub-sensors integrated into the structure. The present study shows the possibility of using the sensor to deduce the local instantaneous host stiffness. Damaged structures are characterized by a reduction in their elastic stiffness that evolve from microstructural defects. A local smart sensor can be developed to sense the local average properties on a host. In this paper, sensors are attached to a structure and a modified Eshelby's equivalent inclusion method is used to derive the elastic properties of the host. An analytical derivation and a sensitivity analysis for the quasistatic application is given in a papers by Majed, Dasgupta, Kelah and Pines. A summary of the derivation of the dynamic Eshelby tensor is presented. This is of importance because damage detection in structures undergoing vibratory and other motions present a greater challenge than those in quasistatic motion. An in-situ health monitoring active sensor system for a real structure (an aluminum plate with an attached repair patch) under close-to real lifecycle loading conditions is developed. The detection of the onset of any damage to the structure as well as the repair patch and the subsequent monitoring of the growth of this damage constitute important goals of the system. Both experimental and finite element methods were applied. Experimental results are presented for tests of the aluminum plate with the repair patch under monotonic quasi-static and dynamic loading vibratory conditions. In summary, the

  15. Simplified Aerodynamic and Structural Modeling for Oblique All-Wing Aircraft. Phase 2: Structures

    NASA Technical Reports Server (NTRS)

    Kroo, Ilan (Principal Investigator)

    1994-01-01

    Any aircraft preliminary design study requires a structural model of the proposed configuration. The model must be capable of estimating the structural weight of a given configuration, and of predicting the deflections which will result from foreseen flight and ground loads. The present work develops such a model for the proposed Oblique All Wing airplane. The model is based on preliminary structural work done by Jack Williams and Peter Rudolph at Mdng, and is encoded in a FORTRAN program. As a stand-alone application, the program can calculate the weight CG location, and several types of structural deflections; used in conjunction with an aerodynamics model, the program can be used for mission analysis or sizing studies.

  16. Probing Aircraft Flight Test Hazard Mitigation for the Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) Research Team . Volume 2; Appendices

    NASA Technical Reports Server (NTRS)

    Kelly, Michael J.

    2013-01-01

    The Alternative Fuel Effects on Contrails and Cruise Emissions (ACCESS) Project Integration Manager requested in July 2012 that the NASA Engineering and Safety Center (NESC) form a team to independently assess aircraft structural failure hazards associated with the ACCESS experiment and to identify potential flight test hazard mitigations to ensure flight safety. The ACCESS Project Integration Manager subsequently requested that the assessment scope be focused predominantly on structural failure risks to the aircraft empennage (horizontal and vertical tail). This report contains the Appendices to Volume I.

  17. Application of variable structure system theory to aircraft flight control. [AV-8A and the Augmentor Wing Jet STOL Research Aircraft

    NASA Technical Reports Server (NTRS)

    Calise, A. J.; Kadushin, I.; Kramer, F.

    1981-01-01

    The current status of research on the application of variable structure system (VSS) theory to design aircraft flight control systems is summarized. Two aircraft types are currently being investigated: the Augmentor Wing Jet STOL Research Aircraft (AWJSRA), and AV-8A Harrier. The AWJSRA design considers automatic control of longitudinal dynamics during the landing phase. The main task for the AWJSRA is to design an automatic landing system that captures and tracks a localizer beam. The control task for the AV-8A is to track velocity commands in a hovering flight configuration. Much effort was devoted to developing computer programs that are needed to carry out VSS design in a multivariable frame work, and in becoming familiar with the dynamics and control problems associated with the aircraft types under investigation. Numerous VSS design schemes were explored, particularly for the AWJSRA. The approaches that appear best suited for these aircraft types are presented. Examples are given of the numerical results currently being generated.

  18. Advanced composites structural concepts and materials technologies for primary aircraft structures: Design/manufacturing concept assessment

    NASA Technical Reports Server (NTRS)

    Chu, Robert L.; Bayha, Tom D.; Davis, HU; Ingram, J. ED; Shukla, Jay G.

    1992-01-01

    Composite Wing and Fuselage Structural Design/Manufacturing Concepts have been developed and evaluated. Trade studies were performed to determine how well the concepts satisfy the program goals of 25 percent cost savings, 40 percent weight savings with aircraft resizing, and 50 percent part count reduction as compared to the aluminum Lockheed L-1011 baseline. The concepts developed using emerging technologies such as large scale resin transfer molding (RTM), automatic tow placed (ATP), braiding, out-of-autoclave and automated manufacturing processes for both thermoset and thermoplastic materials were evaluated for possible application in the design concepts. Trade studies were used to determine which concepts carry into the detailed design development subtask.

  19. Advanced Technology Blade testing on the XV-15 Tilt Rotor Research Aircraft

    NASA Technical Reports Server (NTRS)

    Wellman, Brent

    1992-01-01

    The XV-15 Tilt Rotor Research Aircraft has just completed the first series of flight tests with the Advanced Technology Blade (ATB) rotor system. The ATB are designed specifically for flight research and provide the ability to alter blade sweep and tip shape. A number of problems were encountered from first installation through envelope expansion to airplane mode flight that required innovative solutions to establish a suitable flight envelope. Prior to operation, the blade retention hardware had to be requalified to a higher rated centrifugal load, because the blade weight was higher than expected. Early flights in the helicopter mode revealed unacceptably high vibratory control system loads which required a temporary modification of the rotor controls to achieve higher speed flight and conversion to airplane mode. The airspeed in airplane mode was limited, however, because of large static control loads. Furthermore, analyses based on refined ATB blade mass and inertia properties indicated a previously unknown high-speed blade mode instability, also requiring airplane-mode maximum airspeed to be restricted. Most recently, a structural failure of an ATB cuff (root fairing) assembly retention structure required a redesign of the assembly. All problems have been addressed and satisfactory solutions have been found to allow continued productive flight research of the emerging tilt rotor concept.

  20. Evaluation of modal-based damage detection techniques for composite aircraft sandwich structures

    NASA Astrophysics Data System (ADS)

    Oliver, J. A.; Kosmatka, J. B.

    2005-05-01

    Composite sandwich structures are important as structural components in modern lightweight aircraft, but are susceptible to catastrophic failure without obvious forewarning. Internal damage, such as disbonding between skin and core, is detrimental to the structures' strength and integrity and thus must be detected before reaching critical levels. However, highly directional low density cores, such as Nomex honeycomb, make the task of damage detection and health monitoring difficult. One possible method for detecting damage in composite sandwich structures, which seems to have received very little research attention, is analysis of global modal parameters. This study will investigate the viability of modal analysis techniques for detecting skin-core disbonds in carbon fiber-Nomex honeycomb sandwich panels through laboratory testing. A series of carbon fiber prepreg and Nomex honeycomb sandwich panels-representative of structural components used in lightweight composite airframes-were fabricated by means of autoclave co-cure. All panels were of equal dimensions and two were made with predetermined sizes of disbonded areas, created by substituting areas of Teflon release film in place of epoxy film adhesive during the cure. A laser vibrometer was used to capture frequency response functions (FRF) of all panels, and then real and imaginary FRFs at different locations on each plate and operating shapes for each plate were compared. Preliminary results suggest that vibration-based techniques hold promise for damage detection of composite sandwich structures.

  1. Optical Autocovariance Wind Lidar (OAWL): aircraft test-flight history and current plans

    NASA Astrophysics Data System (ADS)

    Tucker, Sara C.; Weimer, Carl; Adkins, Mike; Delker, Tom; Gleeson, David; Kaptchen, Paul; Good, Bill; Kaplan, Mike; Applegate, Jeff; Taudien, Glenn

    2015-09-01

    To address mission risk and cost limitations the US has faced in putting a much needed Doppler wind lidar into space, Ball Aerospace and Technologies Corp, with support from NASA's Earth Science Technology Office (ESTO), has developed the Optical Autocovariance Wind Lidar (OAWL), designed to measure winds from aerosol backscatter at the 355 nm or 532 nm wavelengths. Preliminary proof of concept hardware efforts started at Ball back in 2004. From 2008 to 2012, under an ESTO-funded Instrument Incubator Program, Ball incorporated the Optical Autocovariance (OA) interferometer receiver into a prototype breadboard lidar system by adding a laser, telescope, and COTS-based data system for operation at the 355 nm wavelength. In 2011, the prototype system underwent ground-based validation testing, and three months later, after hardware and software modifications to ensure autonomous operation and aircraft safety, it was flown on the NASA WB-57 aircraft. The history of the 2011 test flights are reviewed, including efforts to get the system qualified for aircraft flights, modifications made during the flight test period, and the final flight data results. We also present lessons learned and plans for the new, robust, two-wavelength, aircraft system with flight demonstrations planned for Spring 2016.

  2. Crashworthiness of light aircraft fuselage structures: A numerical and experimental investigation

    NASA Technical Reports Server (NTRS)

    Nanyaro, A. P.; Tennyson, R. C.; Hansen, J. S.

    1984-01-01

    The dynamic behavior of aircraft fuselage structures subject to various impact conditions was investigated. An analytical model was developed based on a self-consistent finite element (CFE) formulation utilizing shell, curved beam, and stringer type elements. Equations of motion were formulated and linearized (i.e., for small displacements), although material nonlinearity was retained to treat local plastic deformation. The equations were solved using the implicit Newmark-Beta method with a frontal solver routine. Stiffened aluminum fuselage models were also tested in free flight using the UTIAS pendulum crash test facility. Data were obtained on dynamic strains, g-loads, and transient deformations (using high speed photography in the latter case) during the impact process. Correlations between tests and predicted results are presented, together with computer graphics, based on the CFE model. These results include level and oblique angle impacts as well as the free-flight crash test. Comparisons with a hybrid, lumped mass finite element computer model demonstrate that the CFE formulation provides the test overall agreement with impact test data for comparable computing costs.

  3. A Study of the Utilization of Advanced Composites in Fuselage Structures of Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Watts, D. J.; Sumida, P. T.; Bunin, B. L.; Janicki, G. S.; Walker, J. V.; Fox, B. R.

    1985-01-01

    A study was conducted to define the technology and data needed to support the introduction of advanced composites in the future production of fuselage structure in large transport aircraft. Fuselage structures of six candidate airplanes were evaluated for the baseline component. The MD-100 was selected on the basis of its representation of 1990s fuselage structure, an available data base, its impact on the schedule and cost of the development program, and its availability and suitability for flight service evaluation. Acceptance criteria were defined, technology issues were identified, and a composite fuselage technology development plan, including full-scale tests, was identified. The plan was based on composite materials to be available in the mid to late 1980s. Program resources required to develop composite fuselage technology are estimated at a rough order of magnitude to be 877 man-years exclusive of the bird strike and impact dynamic test components. A conceptual composite fuselage was designed, retaining the basic MD-100 structural arrangement for doors, windows, wing, wheel wells, cockpit enclosure, major bulkheads, etc., resulting in a 32 percent weight savings.

  4. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Vlahopoulos, Nickolas; Schiller, Noah H.

    2011-01-01

    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  5. Evaluation of Braided Stiffener Concepts for Transport Aircraft Wing Structure Applications

    NASA Technical Reports Server (NTRS)

    Deaton, Jerry W.; Dexter, H. Benson (Editor); Markus, Alan; Rohwer, Kim

    1995-01-01

    Braided composite materials have potential for application in aircraft structures. Stiffeners, wing spars, floor beams, and fuselage frames are examples where braided composites could find application if cost effective processing and damage requirements are met. Braiding is an automated process for obtaining near-net shape preforms for fabrication of components for structural applications. Previous test results on braided composite materials obtained at NASA Langley indicate that damage tolerance requirements can be met for some applications. In addition, the braiding industry is taking steps to increase the material through-put to be more competitive with other preform fabrication processes. Data are presented on the compressive behavior of three braided stiffener preform fabric constructions as determined from individual stiffener crippling test and three stiffener wide panel tests. Stiffener and panel fabrication are described and compression data presented for specimens tested with and without impact damage. In addition, data are also presented on the compressive behavior of the stitched stiffener preform construction currently being used by McDonnell Douglas Aerospace in the NASA ACT wing development program.

  6. Effect of temperature on composite sandwich structures subjected to low velocity impact. [aircraft construction materials

    NASA Technical Reports Server (NTRS)

    Sharma, A. V.

    1980-01-01

    The effect of low velocity projectile impact on sandwich-type structural components was investigated. The materials used in the fabrication of the impact surface were graphite-, Kevlar-, and boron-fibers with appropriate epoxy matrices. The testing of the specimens was performed at moderately low- and high-temperatures as well as at room temperature to assess the impact-initiated strength degradation of the laminates. Eleven laminates with different stacking sequences, orientations, and thicknesses were tested. The low energy projectile impact is considered to simulate the damage caused by runway debris, the dropping of the hand tools during servicing, etc., on the secondary aircraft structures fabricated with the composite materials. The results show the preload and the impact energy combinations necessary to cause catastrophic failure in the laminates tested. A set of faired curves indicating the failure thresholds is shown separately for the tension-and compression-loaded laminates. The specific-strengths and -modulii for the various laminates tested are also given.

  7. Results of Tests on Radiators for Aircraft Engines

    NASA Technical Reports Server (NTRS)

    Dickinson, H C; James, W S; Kleinschmidt, R V

    1920-01-01

    Part 1 is to present the results of tests on 56 types of core in a form convenient for use in the study of the performance of and possible improvements in existing designs. Working rules are given by which the data contained in the report may be used, and the most obvious conclusions as to the behavior of cores are summarized. Part 2 presents the results of tests made to determine the pressure necessary to produce water flows up to 50 gallons per minute through an 8-inch square section of radiator core. These data are of special value in evaluating the hydraulic head against which the circulating pump is required to operate.

  8. Structural health monitoring methodology for aircraft condition-based maintenance

    NASA Astrophysics Data System (ADS)

    Saniger, Jordi; Reithler, Livier; Guedra-Degeorges, Didier; Takeda, Nobuo; Dupuis, Jean Pierre

    2001-06-01

    Reducing maintenance costs while keeping a constant level of safety is a major issue for Air Forces and airlines. The long term perspective is to implement condition based maintenance to guarantee a constant safety level while decreasing maintenance costs. On this purpose, the development of a generalized Structural Health Monitoring System (SHMS) is needed. The objective of such a system is to localize the damages and to assess their severity, with enough accuracy to allow low cost corrective actions. The present paper describes a SHMS based on acoustic emission technology. This choice was driven by its reliability and wide use in the aerospace industry. The described SHMS uses a new learning methodology which relies on the generation of artificial acoustic emission events on the structure and an acoustic emission sensor network. The calibrated acoustic emission events picked up by the sensors constitute the knowledge set that the system relies on. With this methodology, the anisotropy of composite structures is taken into account, thus avoiding the major cause of errors of classical localization methods. Moreover, it is adaptive to different structures as it does not rely on any particular model but on measured data. The acquired data is processed and the event's location and corrected amplitude are computed. The methodology has been demonstrated and experimental tests on elementary samples presented a degree of accuracy of 1cm.

  9. Flight parameters monitoring system for tracking structural integrity of rotary-wing aircraft

    NASA Technical Reports Server (NTRS)

    Mohammadi, Jamshid; Olkiewicz, Craig

    1994-01-01

    Recent developments in advanced monitoring systems used in conjunction with tracking structural integrity of rotary-wing aircraft are explained. The paper describes: (1) an overview of rotary-wing aircraft flight parameters that are critical to the aircraft loading conditions and each parameter's specific requirements in terms of data collection and processing; (2) description of the monitoring system and its functions used in a survey of rotary-wing aircraft; and (3) description of the method of analysis used for the data. The paper presents a newly-developed method in compiling flight data. The method utilizes the maneuver sequence of events in several pre-identified flight conditions to describe various flight parameters at three specific weight ranges.

  10. Parameter estimation techniques and application in aircraft flight testing

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Technical papers presented at the symposium by selected representatives from industry, universities, and various Air Force, Navy, and NASA installations are given. The topics covered include the newest developments in identification techniques, the most recent flight-test experience, and the projected potential for the near future.

  11. Missile and aircraft field test data acquired with the rapid optical beam steering (ROBS) sensor system

    NASA Astrophysics Data System (ADS)

    MacDonald, Bruce; Dunn, Murray; Herr, David W.; Hyman, Howard; Leslie, Daniel H.; Lovern, Michael G.

    1997-08-01

    The ROBS instrument has recently acquired unique imagery of a missile intercepting an airborne drone target. We present a summary of that mission. We also present imagery of three airborne targets collected while the ROBS instrument simultaneously tracked all three aircraft. The recent test data highlights the capability of the ROBS instrument for autonomous acquisition, tracking, and imaging of multiple targets under field test conditions. We also describe improvements to the optical system currently underway.

  12. An artificial intelligence-based structural health monitoring system for aging aircraft

    NASA Technical Reports Server (NTRS)

    Grady, Joseph E.; Tang, Stanley S.; Chen, K. L.

    1993-01-01

    To reduce operating expenses, airlines are now using the existing fleets of commercial aircraft well beyond their originally anticipated service lives. The repair and maintenance of these 'aging aircraft' has therefore become a critical safety issue, both to the airlines and the Federal Aviation Administration. This paper presents the results of an innovative research program to develop a structural monitoring system that will be used to evaluate the integrity of in-service aerospace structural components. Currently in the final phase of its development, this monitoring system will indicate when repair or maintenance of a damaged structural component is necessary.

  13. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 2: Sections 7 through 11

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The materials and advanced producibility methods that offer potential structural mass savings in the design of the primary structure for a supersonic cruise aircraft are identified and reported. A summary of the materials and fabrication techniques selected for this analytical effort is presented. Both metallic and composite material systems were selected for application to a near-term start-of-design technology aircraft. Selective reinforcement of the basic metallic structure was considered as the appropriate level of composite application for the near-term design.

  14. Crash Testing and Simulation of a Cessna 172 Aircraft: Hard Landing Onto Concrete

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2016-01-01

    A full-scale crash test of a Cessna 172 aircraft was conducted at the Landing and Impact Research Facility at NASA Langley Research Center during the summer of 2015. The purpose of the test was to evaluate the performance of Emergency Locator Transmitters (ELTs) that were mounted at various locations in the aircraft and to generate impact test data for model validation. A finite element model of the aircraft was developed for execution in LSDYNA to simulate the test. Measured impact conditions were 722.4-in/s forward velocity and 276-in/s vertical velocity with a 1.5deg pitch (nose up) attitude. These conditions were intended to represent a survivable hard landing. The impact surface was concrete. During the test, the nose gear tire impacted the concrete, followed closely by impact of the main gear tires. The main landing gear spread outward, as the nose gear stroked vertically. The only fuselage contact with the impact surface was a slight impact of the rearmost portion of the lower tail. Thus, capturing the behavior of the nose and main landing gear was essential to accurately predict the response. This paper describes the model development and presents test-analysis comparisons in three categories: inertial properties, time sequence of events, and acceleration and velocity time-histories.

  15. NASA Langley Distributed Propulsion VTOL Tilt-Wing Aircraft Testing, Modeling, Simulation, Control, and Flight Test Development

    NASA Technical Reports Server (NTRS)

    Rothhaar, Paul M.; Murphy, Patrick C.; Bacon, Barton J.; Gregory, Irene M.; Grauer, Jared A.; Busan, Ronald C.; Croom, Mark A.

    2014-01-01

    Control of complex Vertical Take-Off and Landing (VTOL) aircraft traversing from hovering to wing born flight mode and back poses notoriously difficult modeling, simulation, control, and flight-testing challenges. This paper provides an overview of the techniques and advances required to develop the GL-10 tilt-wing, tilt-tail, long endurance, VTOL aircraft control system. The GL-10 prototype's unusual and complex configuration requires application of state-of-the-art techniques and some significant advances in wind tunnel infrastructure automation, efficient Design Of Experiments (DOE) tunnel test techniques, modeling, multi-body equations of motion, multi-body actuator models, simulation, control algorithm design, and flight test avionics, testing, and analysis. The following compendium surveys key disciplines required to develop an effective control system for this challenging vehicle in this on-going effort.

  16. Advances in Fatigue and Fracture Mechanics Analyses for Metallic Aircraft Structures

    NASA Technical Reports Server (NTRS)

    Newman, J. C., Jr.

    2000-01-01

    This paper reviews some of the advances that have been made in stress analyses of cracked aircraft components, in the understanding of the fatigue and fatigue-crack growth process, and in the prediction of residual strength of complex aircraft structures with widespread fatigue damage. Finite-element analyses of cracked metallic structures are now used to determine accurate stress-intensity factors for cracks at structural details. Observations of small-crack behavior at open and rivet-loaded holes and the development of small-crack theory has lead to the prediction of stress-life behavior for components with stress concentrations under aircraft spectrum loading. Fatigue-crack growth under simulated aircraft spectra can now be predicted with the crack-closure concept. Residual strength of cracked panels with severe out-of-plane deformations (buckling) in the presence of stiffeners and multiple-site damage can be predicted with advanced elastic-plastic finite-element analyses and the critical crack-tip-opening angle (CTOA) fracture criterion. These advances are helping to assure continued safety of aircraft structures.

  17. Subscale Flight Testing for Aircraft Loss of Control: Accomplishments and Future Directions

    NASA Technical Reports Server (NTRS)

    Cox, David E.; Cunningham, Kevin; Jordan, Thomas L.

    2012-01-01

    Subscale flight-testing provides a means to validate both dynamic models and mitigation technologies in the high-risk flight conditions associated with aircraft loss of control. The Airborne Subscale Transport Aircraft Research (AirSTAR) facility was designed to be a flexible and efficient research facility to address this type of flight-testing. Over the last several years (2009-2011) it has been used to perform 58 research flights with an unmanned, remotely-piloted, dynamically-scaled airplane. This paper will present an overview of the facility and its architecture and summarize the experimental data collected. All flights to date have been conducted within visual range of a safety observer. Current plans for the facility include expanding the test volume to altitudes and distances well beyond visual range. The architecture and instrumentation changes associated with this upgrade will also be presented.

  18. MODE: Structural Test Article (STA)

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Masters, Brett

    1992-01-01

    Viewgraphs on the Middeck 0-gravity Dynamics Experiment (MODE): Structural Test Article (STA) are presented. Topics covered include: MODE: structural test article motivation; hardware; sensors and actuators; experimental support module; data; preliminary results; supporting analysis program; and modeling approach.

  19. Hypersonic airframe structures: Technology needs and flight test requirements

    NASA Technical Reports Server (NTRS)

    Stone, J. E.; Koch, L. C.

    1979-01-01

    Hypersonic vehicles, that may be produced by the year 2000, were identified. Candidate thermal/structural concepts that merit consideration for these vehicles were described. The current status of analytical methods, materials, manufacturing techniques, and conceptual developments pertaining to these concepts were reviewed. Guidelines establishing meaningful technology goals were defined and twenty-eight specific technology needs were identified. The extent to which these technology needs can be satisfied, using existing capabilities and facilities without the benefit of a hypersonic research aircraft, was assessed. The role that a research aircraft can fill in advancing this technology was discussed and a flight test program was outlined. Research aircraft thermal/structural design philosophy was also discussed. Programs, integrating technology advancements with the projected vehicle needs, were presented. Program options were provided to reflect various scheduling and cost possibilities.

  20. The optimization of aircraft seat cushion fire-blocking layers. Full Scale: Test description and results

    NASA Technical Reports Server (NTRS)

    Schutter, K. J.; Duskin, F. E.

    1982-01-01

    Full-scale burn tests were conducted on thirteen different seat cushion configurations in a cabin fire simulator. The fire source used was a quartz lamp radiant energy panel with a propane pilot flame. During each test, data were recorded for cushion temperatures, radiant heat flux, rate of weight loss of test specimens, and cabin temperatures. When compared to existing passenger aircraft seat cushions, the test specimens incorporating a fire barrier and those fabricated from advance materials, using improved construction methods, exhibited significantly greater fire resistance.

  1. Reliability analysis applied to structural tests

    NASA Technical Reports Server (NTRS)

    Diamond, P.; Payne, A. O.

    1972-01-01

    The application of reliability theory to predict, from structural fatigue test data, the risk of failure of a structure under service conditions because its load-carrying capability is progressively reduced by the extension of a fatigue crack, is considered. The procedure is applicable to both safe-life and fail-safe structures and, for a prescribed safety level, it will enable an inspection procedure to be planned or, if inspection is not feasible, it will evaluate the life to replacement. The theory has been further developed to cope with the case of structures with initial cracks, such as can occur in modern high-strength materials which are susceptible to the formation of small flaws during the production process. The method has been applied to a structure of high-strength steel and the results are compared with those obtained by the current life estimation procedures. This has shown that the conventional methods can be unconservative in certain cases, depending on the characteristics of the structure and the design operating conditions. The suitability of the probabilistic approach to the interpretation of the results from full-scale fatigue testing of aircraft structures is discussed and the assumptions involved are examined.

  2. Selected topics from the structural acoustics program for the B-1 aircraft

    NASA Technical Reports Server (NTRS)

    Belcher, P. M.

    1979-01-01

    The major elements of the structural acoustics program for the B-1 aircraft are considered. Acoustic pressures measured at 280 sites on the surface of the vehicle were used to develop pressure models for a resizing of airframe components for aircraft No. 4 (A/C4). Acoustical fatigue design data for two dynamically complex structural configurations were acquired in laboratory programs, the conceptions for and executions of which detailed significant departures from the conventional. Design requirements for mechanical fasteners for configurations other than these two made use of analytical extensions of regrettably limited available information.

  3. High heat flux actively cooled honeycomb sandwich structural panel for a hypersonic aircraft

    NASA Technical Reports Server (NTRS)

    Koch, L. C.; Pagel, L. L.

    1978-01-01

    The results of a program to design and fabricate an unshielded actively cooled structural panel for a hypersonic aircraft are presented. The design is an all-aluminum honeycomb sandwich with embedded cooling passages soldered to the inside of the outer moldline skin. The overall finding is that an actively cooled structure appears feasible for application on a hypersonic aircraft, but the fabrication process is complex and some material and manufacturing technology developments are required. Results from the program are summarized and supporting details are presented.

  4. Certification of Discontinuous Composite Material Forms for Aircraft Structures

    NASA Astrophysics Data System (ADS)

    Arce, Michael Roger

    New, high performance chopped, discontinuous, or short fiber composites (DFCs), DFCs, such as HexMC and Lytex, made by compression molding of randomly oriented pre-impregnated unidirectional tape, can be formed into complex geometry while retaining mechanical properties suitable for structural use. These DFCs provide the performance benefits of Continuous Fiber Composites (CFCs) in form factors that were previously unavailable. These materials demonstrate some notably different properties from continuous fiber composites, especially with respect to damage tolerance and failure behavior. These behaviors are not very well understood, and fundamental research efforts are ongoing to better characterize the material and to ease certification for future uses. Despite this, these new DFCs show such promise that they are already in service in the aerospace industry, for instance in the Boeing 787. Unfortunately, the relative novelty of these parts means that they needed to be certified by “point design”, an excess of physical testing, rather than by a mix of physical testing and finite element analysis, which would be the case for CFCs or metals. In this study, one particular approach to characterizing both linear-elastic and failure behaviors are considered. The Stochastic Laminate Analogy, which represents a novel approach to modeling DFCs, and its combination with a Ply Discount scheme. Owing to limited available computational resources, only preliminary results are available, but those results are quite promising and warrant further investigation.

  5. Design, fabrication and testing of a liquid hydrogen fuel tank for a long duration aircraft

    NASA Astrophysics Data System (ADS)

    Mills, Gary L.; Buchholtz, Brian; Olsen, Al

    2012-06-01

    Liquid hydrogen has distinct advantages as an aircraft fuel. These include a specific heat of combustion 2.8 times greater than gasoline or jet fuel and zero carbon emissions. It can be utilized by fuel cells, turbine engines and internal combustion engines. The high heat of combustion is particularly important in the design of long endurance aircraft with liquid hydrogen enabling cruise endurance of several days. However, the mass advantage of the liquid hydrogen fuel will result in a mass advantage for the fuel system only if the liquid hydrogen tank and insulation mass is a small fraction of the hydrogen mass. The challenge is producing a tank that meets the mass requirement while insulating the cryogenic liquid hydrogen well enough to prevent excessive heat leak and boil off. In this paper, we report on the design, fabrication and testing of a liquid hydrogen fuel tank for a prototype high altitude long endurance (HALE) demonstration aircraft. Design options on tank geometry, tank wall material and insulation systems are discussed. The final design is an aluminum sphere insulated with spray on foam insulation (SOFI). Several steps and organizations were involved in the tank fabrication and test. The tank was cold shocked, helium leak checked and proof pressure tested. The overall thermal performance was verified with a boil off test using liquid hydrogen.

  6. Prismatic sealed nickel-cadmium batteries utilizing fiber structured electrodes. II - Applications as a maintenance free aircraft battery

    NASA Astrophysics Data System (ADS)

    Anderman, Menahem; Benczur-Urmossy, Gabor; Haschka, Friedrich

    Test data on prismatic sealed Ni-Cd batteries utilizing fiber structured electrodes (sealed FNC) is discussed. It is shown that, under a voltage limited charging scheme, the charge acceptance of the sealed FNC battery is far superior to that of the standard vented aircraft Ni-Cd batteries. This results in the sealed FNC battery maintaining its capacity over several thousand cycles without any need for electrical conditioning or water topping. APU start data demonstrate superior power capabilities over existing technologies. Performance at low temperature is presented. Abuse test results reveal a safe fail mechanism even under severe electrical abuse.

  7. Technical evaluation of Russian aircraft stealth coating and structural materials

    SciTech Connect

    Gac, F.D.; Young, A.T. Jr.; Migliori, A.

    1996-10-01

    Treating aircraft, missiles, and ships with materials that absorb electromagnetic energy continues to be an important technique for reducing a vehicle`s radar cross section (RCS) and improving tis combat effectiveness and survivability. Work at the Russian Scientific Center for Applied Problems in Electrodynamics (SCAPE) has produced and experimentally validated an accurate predictor of the interaction of electromagnetic radiation with discontinuous composite materials consisting of magnetic and/or dielectric particles dispersed in a non-conductive matrix (i.e. percolation systems). The primary purpose of this project was to analyze rf-absorbing coatings and validate manufacturing processes associated with the Russian percolation system designs. An additional objective was to apply the percolation methodology toward a variety of civilian applications by transferring the technology to US industry.

  8. Lateral noise attenuation of the advanced propeller of the propfan test assessment aircraft

    NASA Technical Reports Server (NTRS)

    Chambers, F. W.; Reddy, N. N.; Bartel, H. W.

    1989-01-01

    Lateral noise attenuation characteristics of the advanced propeller are determined using the flight test results of the testbed aircraft, Propfan Test Assessment (PTA), with a single, large-scale propfan. The acoustic data were obtained with an array of ground-mounted microphones positioned at distances up to 2.47 km (8100 feet) to the side of the flight path. The aircraft was flown at a Mach number of 0.31 for a variety of operating conditions. The lateral noise attenuation in a frequency range containing the blade passage frequency of the propeller was found to have positive magnitudes on the propfan side and negative magnitudes on the opposite side. The measured attenuation exhibits a strong dependence upon the elevation angle. The results also display a clear dependence upon the angle at which the propeller and nacelle are mounted on the wing (inflow angle).

  9. Aircraft Engine Noise Research and Testing at the NASA Glenn Research Center

    NASA Technical Reports Server (NTRS)

    Elliott, Dave

    2015-01-01

    The presentation will begin with a brief introduction to the NASA Glenn Research Center as well as an overview of how aircraft engine noise research fits within the organization. Some of the NASA programs and projects with noise content will be covered along with the associated goals of aircraft noise reduction. Topics covered within the noise research being presented will include noise prediction versus experimental results, along with engine fan, jet, and core noise. Details of the acoustic research conducted at NASA Glenn will include the test facilities available, recent test hardware, and data acquisition and analysis methods. Lastly some of the actual noise reduction methods investigated along with their results will be shown.

  10. Ground vibration test of the XV-15 Tiltrotor Research Aircraft and pretest predictions

    NASA Technical Reports Server (NTRS)

    Studebaker, Karen; Abrego, Anita

    1994-01-01

    The first comprehensive ground vibration survey was performed on the XV-15 Tiltrotor Research Aircraft to measure the vibration modes of the airframe and to provide data critical for determining whirl flutter stability margins. The aircraft was suspended by the wings with bungee cords and cables. A NASTRAN finite element model was used in the design of the suspension system to minimize its interference with the wing modes. The primary objective of the test was to measure the dynamic characteristics of the wings and pylons for aeroelastic stability analysis. In addition, over 130 accelerometers were placed on the airframe to characterize the fuselage, wing, and tail vibration. Pretest predictions were made with the NASTRAN model as well as correlations with the test data. The results showed that the suspension system provided the isolation necessary for modal measurements.

  11. Propfan test assessment testbed aircraft stability and control/performance 1/9-scale wind tunnel tests

    NASA Technical Reports Server (NTRS)

    Little, B. H., Jr.; Tomlin, K. H.; Aljabri, A. S.; Mason, C. A.

    1988-01-01

    One-ninth scale wind tunnel model tests of the Propfan Test Assessment (PTA) aircraft were performed in three different NASA facilities. Wing and propfan nacelle static pressures, model forces and moments, and flow field at the propfan plane were measured in these tests. Tests started in June 1985 and were completed in January 1987. These data were needed to assure PTA safety of flight, predict PTA performance, and validate analytical codes that will be used to predict flow fields in which the propfan will operate.

  12. Structural Load Alleviation Applied to Next Generation Aircraft and Wind Turbines

    NASA Technical Reports Server (NTRS)

    Frost, Susan

    2011-01-01

    Reducing the environmental impact of aviation is a goal of the Subsonic Fixed Wing Project under the Fundamental Aeronautics Program of NASAs Aeronautics Research Mission Directorate. Environmental impact of aviation is being addressed by novel aircraft configurations and materials that reduce aircraft weight and increase aerodynamic efficiency. NASA is developing tools to address the challenges of increased airframe flexibility created by wings constructed with reduced structural material and novel light-weight materials. This talk will present a framework and demonstration of a flight control system using optimal control allocation with structural load feedback and constraints to achieve safe aircraft operation. As wind turbines age, they become susceptible to many forms of blade degradation. Results will be presented on work in progress that uses adaptive contingency control for load mitigation in a wind turbine simulation with blade damage progression modeled.

  13. Remote sensing of sediment and chlorophyll with the test-bed aircraft multispectral scanner

    NASA Technical Reports Server (NTRS)

    Bowker, D. E.; Hardesty, C. A.; Jobson, D. J.

    1983-01-01

    An instrument known as the test-bed aircraft multispectral scanner (TBAMS) was used in a research flight over the entrance to the Chesapeake Bay. Upwelled radiances from the TBAMS data were correlated with the water parameters, particularly sediment and chlorophyll a. Several algorithms were demonstrated for monitoring sediment and chlorophyll, with a three-band ratio being the best. The primary advantage of the three-band ratio was found to be its apparent insensitivity to atmospheric and Sun-angle variations.

  14. Resin Film Infusion (RFI) Process Modeling for Large Transport Aircraft Wing Structures

    NASA Technical Reports Server (NTRS)

    Knott, Tamara W.; Loos, Alfred C.

    2000-01-01

    Resin film infusion (RFI) is a cost-effective method for fabricating stiffened aircraft wing structures. The RFI process lends itself to the use of near net shape textile preforms manufactured through a variety of automated textile processes such as knitting and braiding. Often, these advanced fiber architecture preforms have through-the-thickness stitching for improved damage tolerance and delamination resistance. The challenge presently facing RFI is to refine the process to ensure complete infiltration and cure of a geometrically complex shape preform with the high fiber volume fraction needed for structural applications. An accurate measurement of preform permeability is critical for successful modeling of the RFI resin infiltration process. Small changes in the permeability can result in very different infiltration behavior and times. Therefore, it is important to accurately measure the permeabilities of the textile preforms used in the RFI process. The objective of this investigation was to develop test methods that can be used to measure the compaction behavior and permeabilities of high fiber volume fraction, advanced fiber architecture textile preforms. These preforms are often highly compacted due to through-the-thickness stitching used to improve damage tolerance. Test fixtures were designed and fabricated and used to measure both transverse and in-plane permeabilities. The fixtures were used to measure the permeabilities of multiaxial warp knit and triaxial braided preforms at fiber volume fractions from 55% to 65%. In addition, the effects of stitching characteristics, thickness, and batch variability on permeability and compaction behavior were investigated.

  15. Design, analysis, and testing of a reusable wingbox for ballistic evaluation of composite structures

    NASA Technical Reports Server (NTRS)

    Baron, W. G.; Oetting, J. D.

    1990-01-01

    Future fighter aircraft will continue to be subjected to severe mechanical loading and ballistic impact. In the past aircraft primary wing structure was constructed predominantly with aluminum, but with increasing aircraft performance the need for more structurally efficient materials is necessary. In an attempt to achieve structural efficiency requirements, aircraft designers have begun using an increasing amount of composite materials. Composite materials were indicated to have a low level of ballistic tolerance in some applications. Composite materials possess the characteristic of structural tailoring, which was utilized to demonstrate that survivability can be designed into a structure. The combat flight environment subjects fighter aircraft wing structures to the effects of combined loading during ballistic impact. These loads were previously demonstrated independently, i.e., the application of structural load, hydrodynamic ram damage, and the effects of airflow. The objective was to design a reusable test fixture for the ballistic evaluation of advanced composite structures under all the effects of combined loading. The fixture that was developed provides a test bed that can completely simulate the flight environment of a generic fighter aircraft wing, but can be used for an indefinite number and variety of tests. It is intended that this fixture will provide a standardized method of ballistically evaluating an advanced composite primary wing structure. This fixture will be used to accomplish the development of designs and/or advanced concepts that lead to a survivable composite wing structure.

  16. A personal sampler for aircraft engine cold start particles: laboratory development and testing.

    PubMed

    Armendariz, Alfredo; Leith, David

    2003-01-01

    Industrial hygienists in the U.S. Air Force are concerned about exposure of their personnel to jet fuel. One potential source of exposure for flightline ground crews is the plume emitted during the start of aircraft engines in extremely cold weather. The purpose of this study was to investigate a personal sampler, a small tube-and-wire electrostatic precipitator (ESP), for assessing exposure to aircraft engine cold start particles. Tests were performed in the laboratory to characterize the sampler's collection efficiency and to determine the magnitude of adsorption and evaporation artifacts. A low-temperature chamber was developed for the artifact experiments so tests could be performed at temperatures similar to actual field conditions. The ESP collected particles from 0.5 to 20 micro m diameter with greater than 98% efficiency at particle concentrations up to 100 mg/m(3). Adsorption artifacts were less than 5 micro g/m(3) when sampling a high concentration vapor stream. Evaporation artifacts were significantly lower for the ESP than for PVC membrane filters across a range of sampling times and incoming vapor concentrations. These tests indicate that the ESP provides more accurate exposure assessment results than traditional filter-based particle samplers when sampling cold start particles produced by an aircraft engine. PMID:14674798

  17. Development and Flight Testing of a Neural Network Based Flight Control System on the NF-15B Aircraft

    NASA Technical Reports Server (NTRS)

    Bomben, Craig R.; Smolka, James W.; Bosworth, John T.; Silliams-Hayes, Peggy S.; Burken, John J.; Larson, Richard R.; Buschbacher, Mark J.; Maliska, Heather A.

    2006-01-01

    The Intelligent Flight Control System (IFCS) project at the NASA Dryden Flight Research Center, Edwards AFB, CA, has been investigating the use of neural network based adaptive control on a unique NF-15B test aircraft. The IFCS neural network is a software processor that stores measured aircraft response information to dynamically alter flight control gains. In 2006, the neural network was engaged and allowed to learn in real time to dynamically alter the aircraft handling qualities characteristics in the presence of actual aerodynamic failure conditions injected into the aircraft through the flight control system. The use of neural network and similar adaptive technologies in the design of highly fault and damage tolerant flight control systems shows promise in making future aircraft far more survivable than current technology allows. This paper will present the results of the IFCS flight test program conducted at the NASA Dryden Flight Research Center in 2006, with emphasis on challenges encountered and lessons learned.

  18. Anticipated Effectiveness of Active Noise Control in Propeller Aircraft Interiors as Determined by Sound Quality Tests

    NASA Technical Reports Server (NTRS)

    Powell, Clemans A.; Sullivan, Brenda M.

    2004-01-01

    Two experiments were conducted, using sound quality engineering practices, to determine the subjective effectiveness of hypothetical active noise control systems in a range of propeller aircraft. The two tests differed by the type of judgments made by the subjects: pair comparisons in the first test and numerical category scaling in the second. Although the results of the two tests were in general agreement that the hypothetical active control measures improved the interior noise environments, the pair comparison method appears to be more sensitive to subtle changes in the characteristics of the sounds which are related to passenger preference.

  19. Advanced composite aileron for L-1011 transport aircraft: Ground tests and flight evaluation

    NASA Technical Reports Server (NTRS)

    Griffin, C. F.

    1981-01-01

    A composite aileron and a metal aileron were subjected to a series of comparative stiffness and vibration tests. These tests showed that the stiffness and vibration characteristics of the composite aileron are similar to the metal aileron. The first composite ground test article was statically tested to failure which occurred at 139 percent of design ultimate load. The second composite ground test article was tested to verify damage tolerance and fail-safe characteristics. Visible damage was inflicted to the aileron and the aileron was subjected to one lifetime of spectrum fatigue loading. After conducting limit load tests on the aileron, major damage was inflicted to the cover and the aileron was loaded to failure which occurred at 130 percent of design ultimate load. A shipset of composite ailerons were installed on Lockheed's L-1011 flight test aircraft and flown. The composite aileron was flutter-free throughout the flight envelope.

  20. Detection of cracks in multilayer aircraft structures with fasteners using remote field eddy current method

    NASA Astrophysics Data System (ADS)

    Sun, Yushi; Ouyang, Tianhe

    2000-05-01

    The remote-field eddy-current (RFEC) technique has been shown to be highly sensitive to cracks and corrosion that are embedded deep in multi-layer aircraft structures. This paper shows the effectiveness of the approach in detecting cracks in double-layered specimens with fasteners, as well as corrosion specimens. The crack specimens, made by Lockheed George Company in 1980, had two layers held together with ten fasteners. The total thickness is 0.356' for Group A and 0.446' of Group B, respectively. Fatigue cracks were made on different layers and at different depths. The corrosion specimens are of 0.063' thick with 0.006' or 0.002' corrosion wall thinning. Another one or two much thicker plates of aluminum are placed on top of one corrosion specimen during a test. All tests were conducted using a newly developed RFEC system that includes a probe specified for inspecting thick plates. The effect of different parameters, such as excitation frequency, excitation to pick-up coil separation distance, and probe to fastener distance, were studied to determine the optimal test parameters. The system will be demonstrated along with the presentation.

  1. Aircraft wing structural design optimization based on automated finite element modelling and ground structure approach

    NASA Astrophysics Data System (ADS)

    Yang, Weizhu; Yue, Zhufeng; Li, Lei; Wang, Peiyan

    2016-01-01

    An optimization procedure combining an automated finite element modelling (AFEM) technique with a ground structure approach (GSA) is proposed for structural layout and sizing design of aircraft wings. The AFEM technique, based on CATIA VBA scripting and PCL programming, is used to generate models automatically considering the arrangement of inner systems. GSA is used for local structural topology optimization. The design procedure is applied to a high-aspect-ratio wing. The arrangement of the integral fuel tank, landing gear and control surfaces is considered. For the landing gear region, a non-conventional initial structural layout is adopted. The positions of components, the number of ribs and local topology in the wing box and landing gear region are optimized to obtain a minimum structural weight. Constraints include tank volume, strength, buckling and aeroelastic parameters. The results show that the combined approach leads to a greater weight saving, i.e. 26.5%, compared with three additional optimizations based on individual design approaches.

  2. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  3. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 4: Sections 15 through 21

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The analyses performed to provide structural mass estimates for the arrow wing supersonic cruise aircraft are presented. To realize the full potential for structural mass reduction, a spectrum of approaches for the wing and fuselage primary structure design were investigated. The objective was: (1) to assess the relative merits of various structural arrangements, concepts, and materials; (2) to select the structural approach best suited for the Mach 2.7 environment; and (3) to provide construction details and structural mass estimates based on in-depth structural design studies. Production costs, propulsion-airframe integration, and advanced technology assessment are included.

  4. Design and evaluation of a foam-filled hat-stiffened panel concept for aircraft primary structural applications

    NASA Technical Reports Server (NTRS)

    Ambur, Damodar R.

    1993-01-01

    Geodesically stiffened structures are very efficient in carrying combined bending, torsion, and pressure loading that is typical of primary aircraft structures. They are also very damage tolerant since there are multiple load paths available to redistribute loads compared to prismatically stiffened structures. Geodesically stiffened structures utilize continuous filament composite materials which make them amenable to automated manufacturing processes to reduce cost. The current practice for geodesically stiffened structures is to use a solid blade construction for the stiffener. This stiffener configuration is not an efficient concept and there is a need to identify other stiffener configurations that are more efficient but utilize the same manufacturing process as the solid blade. This paper describes a foam-filled stiffener cross section that is more efficient than a solid-blade stiffener in the load range corresponding to primary aircraft structures. A prismatic hat-stiffener panel design is then selected for structural evaluation in uni-axial compression with and without impact damage. Experimental results for both single stiffener specimens and multi-stiffener panel specimens are presented. Finite element analysis results are presented that predict the buckling and postbuckling response of the test specimens. Analytical results for both the element and panel specimens are compared with experimental results.

  5. Development of Advanced Methods of Structural and Trajectory Analysis for Transport Aircraft

    NASA Technical Reports Server (NTRS)

    Ardema, Mark D.

    1996-01-01

    In this report the author describes: (1) development of advanced methods of structural weight estimation, and (2) development of advanced methods of flight path optimization. A method of estimating the load-bearing fuselage weight and wing weight of transport aircraft based on fundamental structural principles has been developed. This method of weight estimation represents a compromise between the rapid assessment of component weight using empirical methods based on actual weights of existing aircraft and detailed, but time-consuming, analysis using the finite element method. The method was applied to eight existing subsonic transports for validation and correlation. Integration of the resulting computer program, PDCYL, has been made into the weights-calculating module of the AirCraft SYNThesis (ACSYNT) computer program. ACSYNT bas traditionally used only empirical weight estimation methods; PDCYL adds to ACSYNT a rapid, accurate means of assessing the fuselage and wing weights of unconventional aircraft. PDCYL also allows flexibility in the choice of structural concept, as well as a direct means of determining the impact of advanced materials on structural weight.

  6. Transport jet aircraft noise abatement in foreign countries: Growth, structure, impact. Volume 1: Europe, July 1980

    NASA Technical Reports Server (NTRS)

    Spencer, F. A.

    1980-01-01

    The development and implementation of aircraft noise control regulations in various European states are described. The countries include the United Kingdom, France, Switzerland, Federal Republic of Germany, Sweden, Denmark, and the Netherlands. Topics discussed include noise monitoring, airport curfews, land use planning, and the government structure for noise regulation.

  7. The Goodrich 3rd generation DB-110 system: successful flight test on the F-16 aircraft

    NASA Astrophysics Data System (ADS)

    Lange, Davis; Iyengar, Mrinal; Maver, Larry; Dyer, Gavin; Francis, John

    2007-04-01

    The 3rd Generation Goodrich DB-110 system provides users with a three (3) field-of-view high performance Airborne Reconnaissance capability that incorporates a dual-band day and nighttime imaging sensor, a real time recording and a real time data transmission capability to support long range, medium range, and short range standoff and over-flight mission scenarios, all within a single pod. Goodrich developed their 3rd Generation Airborne Reconnaissance Pod for operation on a range of aircraft types including F-16, F-15, F-18, Euro-fighter and older aircraft such as the F-4, F-111, Mirage and Tornado. This system upgrades the existing, operationally proven, 2nd generation DB-110 design with enhancements in sensor resolution, flight envelope and other performance improvements. Goodrich recently flight tested their 3rd Generation Reconnaissance System on a Block 52 F-16 aircraft with first flight success and excellent results. This paper presents key highlights of the system and presents imaging results from flight test.

  8. Flight Test Experience with an Electromechanical Actuator on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Jensen, Stephen C.; Jenney, Gavin D.; Raymond, Bruce; Dawson, David; Flick, Brad (Technical Monitor)

    2000-01-01

    Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a series of actuators validating power-by-wire actuation technology on a primary flight control surface of a tactical aircraft. To achieve this goal, each of the EPAD actuators was installed in place of the standard hydraulic actuator on the left aileron of the NASA F/A-18B Systems Research Aircraft (SRA) and flown throughout the SRA flight envelope. Numerous parameters were recorded, and overall actuator performance was compared with the performance of the standard hydraulic actuator on the opposite wing. This paper discusses the integration and testing of the EPAD electromechanical actuator (EMA) on the SRA. The architecture of the EMA system is discussed, as well as its integration with the F/A-18 Flight Control System. The flight test program is described, and actuator performance is shown to be very close to that of the standard hydraulic actuator it replaced. Lessons learned during this program are presented and discussed, as well as suggestions for future research.

  9. Flight Test Experience With an Electromechanical Actuator on the F-18 Systems Research Aircraft

    NASA Technical Reports Server (NTRS)

    Jensen, Stephen C.; Jenney, Gavin D.; Raymond, Bruce; Dawson, David

    2000-01-01

    Development of reliable power-by-wire actuation systems for both aeronautical and space applications has been sought recently to eliminate hydraulic systems from aircraft and spacecraft and thus improve safety, efficiency, reliability, and maintainability. The Electrically Powered Actuation Design (EPAD) program was a joint effort between the Air Force, Navy, and NASA to develop and fly a series of actuators validating power-by-wire actuation technology on a primary flight control surface of a tactical aircraft. To achieve this goal, each of the EPAD actuators was installed in place of the standard hydraulic actuator on the left aileron of the NASA F/A-18B Systems Research Aircraft (SRA) and flown throughout the SRA flight envelope. Numerous parameters were recorded, and overall actuator performance was compared with the performance of the standard hydraulic actuator on the opposite wing. This paper discusses the integration and testing of the EPAD electromechanical actuator (EMA) on the SRA. The architecture of the EMA system is discussed, as well as its integration with the F/A-18 Flight Control System. The flight test program is described, and actuator performance is shown to be very close to that of the standard hydraulic actuator it replaced. Lessons learned during this program are presented and discussed, as well as suggestions for future research.

  10. Progress in manufacturing large primary aircraft structures using the stitching/RTM process

    NASA Technical Reports Server (NTRS)

    Markus, Alan; Thrash, Patrick; Rohwer, Kim

    1993-01-01

    The Douglas Aircraft/NASA Act contract has been focused over the past three years at developing a materials, manufacturing, and cost base for stitched/Resin Transfer Molded (RTM) composites. The goal of the program is to develop RTM and stitching technology to provide enabling technology for application of these materials in primary aircraft structure with a high degree of confidence. Presented in this paper will be the progress to date in the area of manufacturing and associated cost values of stitched/RTM composites.

  11. Aerodynamic Parameters of High Performance Aircraft Estimated from Wind Tunnel and Flight Test Data

    NASA Technical Reports Server (NTRS)

    Klein, Vladislav; Murphy, Patrick C.

    1999-01-01

    A concept of system identification applied to high performance aircraft is introduced followed by a discussion on the identification methodology. Special emphasis is given to model postulation using time invariant and time dependent aerodynamic parameters, model structure determination and parameter estimation using ordinary least squares and mixed estimation methods. At the same time problems of data collinearity detection and its assessment are discussed. These parts of methodology are demonstrated in examples using flight data of the X-29A and X-31A aircraft. In the third example wind tunnel oscillatory data of the F-16XL model are used. A strong dependence of these data on frequency led to the development of models with unsteady aerodynamic terms in the form of indicial functions. The paper is completed by concluding remarks.

  12. Aerodynamic Parameters of High Performance Aircraft Estimated from Wind Tunnel and Flight Test Data

    NASA Technical Reports Server (NTRS)

    Klein, Vladislav; Murphy, Patrick C.

    1998-01-01

    A concept of system identification applied to high performance aircraft is introduced followed by a discussion on the identification methodology. Special emphasis is given to model postulation using time invariant and time dependent aerodynamic parameters, model structure determination and parameter estimation using ordinary least squares an mixed estimation methods, At the same time problems of data collinearity detection and its assessment are discussed. These parts of methodology are demonstrated in examples using flight data of the X-29A and X-31A aircraft. In the third example wind tunnel oscillatory data of the F-16XL model are used. A strong dependence of these data on frequency led to the development of models with unsteady aerodynamic terms in the form of indicial functions. The paper is completed by concluding remarks.

  13. An Integrated Architecture for Aircraft Engine Performance Monitoring and Fault Diagnostics: Engine Test Results

    NASA Technical Reports Server (NTRS)

    Rinehart, Aidan W.; Simon, Donald L.

    2014-01-01

    This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

  14. An Integrated Architecture for Aircraft Engine Performance Monitoring and Fault Diagnostics: Engine Test Results

    NASA Technical Reports Server (NTRS)

    Rinehart, Aidan W.; Simon, Donald L.

    2015-01-01

    This paper presents a model-based architecture for performance trend monitoring and gas path fault diagnostics designed for analyzing streaming transient aircraft engine measurement data. The technique analyzes residuals between sensed engine outputs and model predicted outputs for fault detection and isolation purposes. Diagnostic results from the application of the approach to test data acquired from an aircraft turbofan engine are presented. The approach is found to avoid false alarms when presented nominal fault-free data. Additionally, the approach is found to successfully detect and isolate gas path seeded-faults under steady-state operating scenarios although some fault misclassifications are noted during engine transients. Recommendations for follow-on maturation and evaluation of the technique are also presented.

  15. Improved test methods for determining lightning-induced voltages in aircraft

    NASA Technical Reports Server (NTRS)

    Crouch, K. E.; Plumer, J. A.

    1980-01-01

    A lumped parameter transmission line with a surge impedance matching that of the aircraft and its return lines was evaluated as a replacement for earlier current generators. Various test circuit parameters were evaluated using a 1/10 scale relative geometric model. Induced voltage response was evaluated by taking measurements on the NASA-Dryden Digital Fly by Wire F-8 aircraft. Return conductor arrangements as well as other circuit changes were also evaluated, with all induced voltage measurements being made on the same circuit for comparison purposes. The lumped parameter transmission line generates a concave front current wave with the peak di/dt near the peak of the current wave which is more representative of lightning. However, the induced voltage measurements when scaled by appropriate scale factors (peak current or di/dt) resulting from both techniques yield comparable results.

  16. Survey - Applications of structural optimization methods to fixed wing aircraft and spacecraft

    NASA Technical Reports Server (NTRS)

    Miura, Hirokazu; Neill, Douglas J.

    1992-01-01

    Results of a technical survey of the practical applications of structural optimization methods in the U.S. aerospace industry through 1980s are summarized. One of the most important developments in the 80s is the more widespread acceptance of structural optimization as one of the design tools that support practical structural design. Another significant advance is the development of large software tools for production applications. Attention is also given to the tailoring of the computerized design process to the specific environment of each company. The two most important aspects of this tailoring are seamless and easy-to-use incorporation of structural optimization in the overall aerospace design/production process and multidisciplinary integration aimed at ultimate performance optimization of the final product. Some specific applications discussed include the X-29 forward swept wing demonstrator aircraft, composite wing and vertical tail program, fighter wing redesign evaluations, high speed aircraft design, and space structures.

  17. Conduct overall test operations and evaluate two Doppler systems to detect, track and measure velocities in aircraft wake vortices

    NASA Technical Reports Server (NTRS)

    Wilson, D. J.; Krause, M. C.; Craven, C. E.; Edwards, B. B.; Coffey, E. W.; Huang, C. C.; Jetton, J. L.; Morrison, L. K.

    1974-01-01

    A program plan for system evaluation of the two-dimensional Scanning Laser Doppler System (SLDS) is presented. In order to meet system evaluation and optimization objectives the following tests were conducted: (1) noise tests; (2) wind tests; (3) blower flowfield tests; (4) single unit (1-D) flyby tests; and (5) dual unit (2-D) flyby tests. Test results are reported. The final phase of the program included logistics preparation, equipment interface checkouts, and data processing. It is concluded that the SLDS is capable of accurately tracking aircraft wake vortices from small or large aircraft, and in any type of weather.

  18. Full-scale testing, production and cost analysis data for the advanced composite stabilizer for Boeing 737 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Aniversario, R. B.; Harvey, S. T.; Mccarty, J. E.; Parson, J. T.; Peterson, D. C.; Pritchett, L. D.; Wilson, D. R.; Wogulis, E. R.

    1982-01-01

    The development, testing, production activities, and associated costs that were required to produce five-and-one-half advanced-composite stabilizer shipsets for Boeing 737 aircraft are defined and discussed.

  19. Study on utilization of advanced composites in commercial aircraft wing structures. Volume 1: Executive summary

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Ostrom, R. B.; Cardinale, S. V.

    1978-01-01

    The effort required by commercial transport manufacturers to accomplish the transition from current construction materials and practices to extensive use of composites in aircraft wings was investigated. The engineering and manufacturing disciplines which normally participate in the design, development, and production of an aircraft were employed to ensure that all of the factors that would enter a decision to commit to production of a composite wing structure were addressed. A conceptual design of an advanced technology reduced energy aircraft provided the framework for identifying and investigating unique design aspects. A plan development effort defined the essential technology needs and formulated approaches for effecting the required wing development. The wing development program plans, resource needs, and recommendations are summarized.

  20. Techniques for hot structures testing

    NASA Technical Reports Server (NTRS)

    Deangelis, V. Michael; Fields, Roger A.

    1990-01-01

    Hot structures testing have been going on since the early 1960's beginning with the Mach 6, X-15 airplane. Early hot structures test programs at NASA-Ames-Dryden focused on operational testing required to support the X-15 flight test program, and early hot structures research projects focused on developing lab test techniques to simulate flight thermal profiles. More recent efforts involved numerous large and small hot structures test programs that served to develop test methods and measurement techniques to provide data that promoted the correlation of test data with results from analytical codes. In Nov. 1988 a workshop was sponsored that focused on the correlation of hot structures test data with analysis. Limited material is drawn from the workshop and a more formal documentation is provided of topics that focus on hot structures test techniques used at NASA-Ames-Dryden. Topics covered include the data acquisition and control of testing, the quartz lamp heater systems, current strain and temperature sensors, and hot structures test techniques used to simulate the flight thermal environment in the lab.

  1. Automatic Aircraft Structural Topology Generation for Multidisciplinary Optimization and Weight Estimation

    NASA Technical Reports Server (NTRS)

    Sensmeier, Mark D.; Samareh, Jamshid A.

    2005-01-01

    An approach is proposed for the application of rapid generation of moderate-fidelity structural finite element models of air vehicle structures to allow more accurate weight estimation earlier in the vehicle design process. This should help to rapidly assess many structural layouts before the start of the preliminary design phase and eliminate weight penalties imposed when actual structure weights exceed those estimated during conceptual design. By defining the structural topology in a fully parametric manner, the structure can be mapped to arbitrary vehicle configurations being considered during conceptual design optimization. A demonstration of this process is shown for two sample aircraft wing designs.

  2. Console test report for shuttle task 501 shuttle carrier aircraft transceiver console (SED 36115353-301)

    NASA Technical Reports Server (NTRS)

    Lane, J. H.

    1976-01-01

    Performance tests completed on the Space Shuttle Carrier Aircraft (SCA) transceiver console, verifying its design objectives, were described. These tests included: (1) check of power supply voltages for correct output voltage and energization at the proper point in the turn on sequence, (2) check of cooling system (LRU blower, overload sensors and circuitry, and thermocouple probe), (3) check of control circuits logic, including the provisions for remote control and display, (4) check of the LRU connector for presence of correct voltages and absence of incorrect voltages under both energized and deenergized conditions, and (5) check of the AGC and power output monitor circuits.

  3. Aircraft flight flutter testing at the NASA Ames-Dryden Flight Research Facility

    NASA Technical Reports Server (NTRS)

    Kehoe, Michael W.

    1988-01-01

    Many parameter identification techniques have been used at the NASA Ames Research Center, Dryden Research Facility at Edwards Air Force Base to determine the aeroelastic stability of new and modified research vehicles in flight. This paper presents a summary of each technique used with emphasis on fast Fourier transform methods. Experiences gained from application of these techniques to various flight test programs are discussed. Also presented are data-smoothing techniques used for test data distorted by noise. Data are presented for various aircraft to demonstrate the accuracy of each parameter identification technique discussed.

  4. Nanosecond resolution of .E, .H and .I in aircraft lightning test rigs

    NASA Astrophysics Data System (ADS)

    Burrows, B. J. C.

    1983-06-01

    Many designs of test rig have emerged in recent years incorporating hardwired connections and design incorporating series open arcs at each end of the aircraft. Important characteristics of the test rigs are not specified, but these characteristics control the generation of large (and usually HF) transients through the fast coupling processes. Both lumped element and distributed element representation of these test rigs and the capacitor banks driving them are given, and the effects of parameter and geometry variations are highlighted. It is shown that quantitative analysis of fast transients (dot-D, dot-B) requires much closer specification of the test rig performance including switch closure time, capacitor bank and connecting line inductance, and the transmission line impedance of the test rig. Tests on the Fly-by-Wire Jaguar at Warton near Preston in England showed the need for developing a quantitative relationship between HF transients and the fast coupling processes.

  5. A novel actuator phasing method for ultrasonic de-icing of aircraft structures

    NASA Astrophysics Data System (ADS)

    Borigo, Cody J.

    Aircraft icing is a critical concern for commercial and military rotorcraft and fixed-wing aircraft. In-flight icing can lead to dramatic decreases in lift and increases in drag that have caused more than a thousand deaths and hundreds of accidents over the past three decades alone. Current ice protection technologies have substantial drawbacks due to weight, power consumption, environmental concerns, or incompatibility with certain structures. In this research, an actuator phasing method for ultrasonic de-icing of aircraft structures was developed and tested using a series of finite element models, 3D scanning laser Doppler vibrometer measurements, and experimental de-icing tests on metallic and composite structures including plates and airfoils. An independent actuator analysis method was developed to allow for practical evaluation of many actuator phasing scenarios using a limited number of finite element models by properly calculating the phased stress fields and electromechanical impedance curves using a complex coupled impedance model. A genetic algorithm was utilized in conjunction with a series of finite element models to demonstrate that phase inversion, in which only in-phase and anti-phase signal components are applied to actuators, can be utilized with a small number of phasing combinations to achieve substantial improvements in de-icing system coverage. Finite element models of a 48"-long airfoil predicted that phase inversion with frequency sweeping can provide an improvement in the shear stress coverage levels of up to 90% compared to frequency sweeping alone. Experimental evaluation of the phasing approach on an icing grid showed a 189% improvement in de-icing coverage compared to frequency sweeping alone at comparable power levels. 3D scanning laser Doppler vibrometer measurements confirmed the increased variation in the surface vibration field induced by actuator phasing compared to unphased frequency sweeping. Additional contributions were made

  6. Celotex Structural Properties Tests

    SciTech Connect

    Smith, A.C.

    2001-01-26

    In the course of regulatory review of the 9975 packaging, the question of the effects environmental conditions on performance of the packaging was raised. The results of previous tests of the Celotex material, used for impact absorption and thermal insulation, indicated that the effect of temperature variation was small. Accordingly, performance under ambient conditions was judged to be representative of performance under temperature extremes. To extend the database to include other effects, and in response to the questions, a series of materials tests were performed on the Celotex brand cellulose fiberboard material.

  7. Enhanced Imaging of Corrosion in Aircraft Structures with Reverse Geometry X-ray(registered tm)

    NASA Technical Reports Server (NTRS)

    Winfree, William P.; Cmar-Mascis, Noreen A.; Parker, F. Raymond

    2000-01-01

    The application of Reverse Geometry X-ray to the detection and characterization of corrosion in aircraft structures is presented. Reverse Geometry X-ray is a unique system that utilizes an electronically scanned x-ray source and a discrete detector for real time radiographic imaging of a structure. The scanned source system has several advantages when compared to conventional radiography. First, the discrete x-ray detector can be miniaturized and easily positioned inside a complex structure (such as an aircraft wing) enabling images of each surface of the structure to be obtained separately. Second, using a measurement configuration with multiple detectors enables the simultaneous acquisition of data from several different perspectives without moving the structure or the measurement system. This provides a means for locating the position of flaws and enhances separation of features at the surface from features inside the structure. Data is presented on aircraft specimens with corrosion in the lap joint. Advanced laminographic imaging techniques utilizing data from multiple detectors are demonstrated to be capable of separating surface features from corrosion in the lap joint and locating the corrosion in multilayer structures. Results of this technique are compared to computed tomography cross sections obtained from a microfocus x-ray tomography system. A method is presented for calibration of the detectors of the Reverse Geometry X-ray system to enable quantification of the corrosion to within 2%.

  8. Evaluation of structural design concepts for an arrow-wing supersonic cruise aircraft

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Davis, G. W.

    1977-01-01

    An analytical study was performed to determine the best structural approach for design of primary wing and fuselage structure of a Mach 2.7 arrow wing supersonic cruise aircraft. Concepts were evaluated considering near term start of design. Emphasis was placed on the complex interactions between thermal stress, static aeroelasticity, flutter, fatigue and fail safe design, static and dynamic loads, and the effects of variations in structural arrangements, concepts and materials on these interactions. Results indicate that a hybrid wing structure incorporating low profile convex beaded and honeycomb sandwich surface panels of titanium alloy 6Al-4V were the most efficient. The substructure includes titanium alloy spar caps reinforced with boron polyimide composites. The fuselage shell consists of hat stiffened skin and frame construction of titanium alloy 6Al-4V. A summary of the study effort is presented, and a discussion of the overall logic, design philosophy and interaction between the analytical methods for supersonic cruise aircraft design are included.

  9. Flight Test Results on the Stability and Control of the F-15 Quiet Spike(TradeMark) Aircraft

    NASA Technical Reports Server (NTRS)

    Moua, Cheng M.; McWherter, Shaun C.; Cox, Timothy H.; Gera, Joe

    2012-01-01

    The Quiet Spike F-15B flight research program investigated supersonic shock reduction using a 24-ft sub-scale telescoping nose boom on an F-15B airplane. The program primary flight test objective was to collect flight data for aerodynamic and structural models validation up to 1.8 Mach. Other objectives were to validate the mechanical feasibility of a morphing fuselage at the operational conditions and determine the near-field shock wave characterization. The stability and controls objectives were to assess the effect of the spike on the stability, controllability, and handling qualities of the aircraft and to ensure adequate stability margins across the entire research flight envelop. The two main stability and controls issues were the effects of the telescoping nose boom influenced aerodynamics on the F-15B aircraft flight dynamics and air data and angle of attack sensors. This paper reports on the stability and controls flight envelope clearance methods and flight test analysis of the F-15B Quiet Spike. Brief pilot commentary on typical piloting tasks, approach and landing, refueling task, and air data sensitivity to the flight control system are also discussed in this report.

  10. Fatigue damage assessment of high-usage in-service aircraft fuselage structure

    NASA Astrophysics Data System (ADS)

    Mosinyi, Bao Rasebolai

    As the commercial and military aircraft fleets continue to age, there is a growing concern that multiple-site damage (MSD) can compromise structural integrity. Multiple site damage is the simultaneous occurrence of many small cracks at independent structural locations, and is the natural result of fatigue, corrosion, fretting and other possible damage mechanisms. These MSD cracks may linkup and form a fatigue lead crack of critical length. The presence of MSD also reduces the structure's ability to withstand longer cracks. The objective of the current study is to assess, both experimentally and analytically, MSD formation and growth in the lap joint of curved panels removed from a retired aircraft. A Boeing 727-232 airplane owned and operated by Delta Air Lines, and retired at its design service goal, was selected for the study. Two panels removed from the left-hand side of the fuselage crown, near stringer 4L, were subjected to extended fatigue testing using the Full-Scale Aircraft Structural Test Evaluation and Research (FASTER) facility located at the Federal Aviation Administration (FAA) William J. Hughes Technical Center. The state of MSD was continuously assessed using several nondestructive inspection (NDI) methods. Damage to the load attachment points of the first panel resulted in termination of the fatigue test at 43,500 fatigue cycles, before cracks had developed in the lap joint. The fatigue test for the second panel was initially conducted under simulated in-service loading conditions for 120,000 cycles, and no cracks were detected in the skin of the panel test section. Artificial damage was then introduced into the panel at selected rivets in the critical (lower) rivet row, and the fatigue loads were increased. Visually detectable crack growth from the artificial notches was first seen after 133,000 cycles. The resulting lead crack grew along the lower rivet row, eventually forming an 11.8" long unstable crack after 141,771 cycles, at which point the

  11. Study on utilization of advanced composites in commercial aircraft wing structures, volume 2

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Ostrom, R. B.

    1978-01-01

    A plan is defined for a composite wing development effort which will assist commercial transport manufacturers in reaching a level of technology readiness where the utilization of composite wing structure is a cost competitive option for a new aircraft production plan. The recommended development effort consists of two programs: a joint government/industry material development program and a wing structure development program. Both programs are described in detail.

  12. In-service inspection methods for graphite-epoxy structures on commercial transport aircraft

    NASA Technical Reports Server (NTRS)

    Phelps, M. L.

    1981-01-01

    In-service inspection methods for graphite-epoxy composite structures on commercial transport aircraft are determined. Graphite/epoxy structures, service incurred defects, current inspection practices and concerns of the airline and manufacturers, and other related information were determind by survey. Based on this information, applicable inspection nondestructive inspection methods are evaluated and inspection techniques determined. Technology is developed primarily in eddy current inspection.

  13. Orthogonal series generalized likelihood ratio test for failure detection and isolation. [for aircraft control

    NASA Technical Reports Server (NTRS)

    Hall, Steven R.; Walker, Bruce K.

    1990-01-01

    A new failure detection and isolation algorithm for linear dynamic systems is presented. This algorithm, the Orthogonal Series Generalized Likelihood Ratio (OSGLR) test, is based on the assumption that the failure modes of interest can be represented by truncated series expansions. This assumption leads to a failure detection algorithm with several desirable properties. Computer simulation results are presented for the detection of the failures of actuators and sensors of a C-130 aircraft. The results show that the OSGLR test generally performs as well as the GLR test in terms of time to detect a failure and is more robust to failure mode uncertainty. However, the OSGLR test is also somewhat more sensitive to modeling errors than the GLR test.

  14. Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 3: Sections 12 through 14

    NASA Technical Reports Server (NTRS)

    Sakata, I. F.; Davis, G. W.

    1975-01-01

    The design of an economically viable supersonic cruise aircraft requires the lowest attainable structural-mass fraction commensurate with the selected near-term structural material technology. To achieve this goal of minimum structural-mass fraction, various combinations of promising wing and fuselage primary structure were analyzed for the load-temperature environment applicable to the arrow wing configuration. This analysis was conducted in accordance with the design criteria specified and included extensive use of computer-aided analytical methods to screen the candidate concepts and select the most promising concepts for the in-depth structural analysis.

  15. Effective L/D: A Theoretical Approach to the Measurement of Aero-Structural Efficiency in Aircraft Design

    NASA Technical Reports Server (NTRS)

    Guynn, Mark D.

    2015-01-01

    There are many trade-offs in aircraft design that ultimately impact the overall performance and characteristics of the final design. One well recognized and well understood trade-off is that of wing weight and aerodynamic efficiency. Higher aerodynamic efficiency can be obtained by increasing wing span, usually at the expense of higher wing weight. The proper balance of these two competing factors depends on the objectives of the design. For example, aerodynamic efficiency is preeminent for sailplanes and long slender wings result. Although the wing weight-drag trade is universally recognized, aerodynamic efficiency and structural efficiency are not usually considered in combination. This paper discusses the concept of "aero-structural efficiency," which combines weight and drag characteristics. A metric to quantify aero-structural efficiency, termed effective L/D, is then derived and tested with various scenarios. Effective L/D is found to be a practical and robust means to simultaneously characterize aerodynamic and structural efficiency in the context of aircraft design. The primary value of the effective L/D metric is as a means to better communicate the combined system level impacts of drag and structural weight.

  16. Finite element thermal analysis of convectively-cooled aircraft structures

    NASA Technical Reports Server (NTRS)

    Wieting, A. R.; Thornton, E. A.

    1981-01-01

    The design complexity and size of convectively-cooled engine and airframe structures for hypersonic transports necessitate the use of large general purpose computer programs for both thermal and structural analyses. Generally thermal analyses are based on the lumped-parameter finite difference technique, and structural analyses are based on the finite element technique. Differences in these techniques make it difficult to achieve an efficient interface. It appears, therefore, desirable to conduct an integrated analysis based on a common technique. A summary is provided of efforts by NASA concerned with the development of an integrated thermal structural analysis capability using the finite element method. Particular attention is given to the development of conduction/forced-convection finite element methodology and applications which illustrate the capabilities of the developed concepts.

  17. On the use of a compact optical fiber sensor system in aircraft structural health monitoring

    NASA Astrophysics Data System (ADS)

    Mrad, Nezih; Guo, Honglei; Xiao, Gaozhi; Rocha, Bruno; Sun, Zhigang

    2012-06-01

    Structural Health Monitoring (SHM) has been identified as an area of significant potential for advanced aircraft maintenance programs that ensure continued airworthiness, enhanced operational safety and reduced life cycle cost. Several sensors and sensory systems have been developed for the implementation of such health monitoring capability. Among a wide range of developed technologies, fiber optic sensor technology, in particular fiber Bragg grating based emerged as one of the most promising for aircraft structural applications. This paper is set to explore the suitability of using a new Fiber Bragg Grating sensor (FBG) system developed for operation in two modes, low and high speed sensing modes, respectively. The suitability of the system for potential use in aircraft load monitoring and damage detection applications has been demonstrated. Results from FBG sensor system were in good agreement with results from conventional resistive strain gauges, validating this capability for load monitoring. For damage detection, the FBG sensor system was able to detect acoustic waves generated 52 inches (1.32 m) away. The initial results, obtained in a full stale experimentation, demonstrate the potential of using FBG sensors for both load monitoring and damage detection in aircraft environment.

  18. Structural development of laminar flow control aircraft chordwise wing joint designs

    NASA Technical Reports Server (NTRS)

    Fischler, J. E.; Jerstad, N. M.; Gallimore, F. H., Jr.; Pollard, T. J.

    1989-01-01

    For laminar flow to be achieved, any protuberances on the surface must be small enough to avoid transition to turbulent flow. However, the surface must have joints between the structural components to allow assembly or replacement of damaged parts, although large continuous surfaces can be utilized to minimize the number the number of joints. Aircraft structural joints usually have many countersunk bolts or rivets on the outer surface. To maintain no mismatch on outer surfaces, it is desirable to attach the components from the inner surface. It is also desirable for the panels to be interchangeable, without the need for shims at the joint, to avoid surface discontinuities that could cause turbulence. Fabricating components while pressing their outer surfaces against an accurate mold helps to ensure surface smoothness and continuity at joints. These items were considered in evaluating the advantages and disadvantages of the joint design concepts. After evaluating six design concepts, two of the leading candidates were fabricated and tested using many small test panels. One joint concept was also built and tested using large panels. The small and large test panel deflections for the leading candidate designs at load factors up to +1.5 g's were well within the step and waviness requirements for avoiding transition.The small panels were designed and tested for compression and tension at -65 F, at ambient conditions, and at 160 F. The small panel results for the three-rib and the sliding-joint concepts indicated that they were both acceptable. The three-rib concept, with tapered splice plates, was considered to be the most practical. A modified three-rib joint that combined the best attributes of previous candidates was designed, developed, and tested. This improved joint met all of the structural strength, surface smoothness, and waviness criteria for laminar flow control (LFC). The design eliminated all disadvantages of the initial three-rib concept except for

  19. Calibration of strain-gage installations in aircraft structures for the measurement of flight loads

    NASA Technical Reports Server (NTRS)

    Skopinski, T H; Aiken, William S , Jr; Huston, Wilber B

    1954-01-01

    A general method has been developed for calibrating strain-gage installations in aircraft structures, which permits the measurement in flight of the shear or lift, the bending moment, and the torque or pitching moment on the principal lifting or control surfaces. Although the stress in structural members may not be a simple function of the three loads of interest, a straightforward procedure is given for numerically combining the outputs of several bridges in such a way that the loads may be obtained. Extensions of the basic procedure by means of electrical combination of the strain-gage bridges are described which permit compromises between strain-gage installation time, availability of recording instruments, and data reduction time. The basic principles of strain-gage calibration procedures are illustrated by reference to the data for two aircraft structures of typical construction, one a straight and the other a swept horizontal stabilizer.

  20. Flight test investigation of certification issues pertaining to general-aviation-type aircraft with natural laminar flow

    NASA Technical Reports Server (NTRS)

    Doty, Wayne A.

    1990-01-01

    Development of Natural Laminar Flow (NLF) technology for application to general aviation-type aircraft has raised some question as to the adequacy of FAR Part 23 for certification of aircraft with significant NLF. A series of flight tests were conducted with a modified Cessna T210R to allow quantitative comparison of the aircraft's ability to meet certification requirements with significant NLF and with boundary layer transition fixed near the leading edge. There were no significant differences between the two conditions except an increasing in drag, which resulted in longer takeoff distances and reduced climb performance.

  1. Ground test experience with large composite structures for commercial transports

    NASA Technical Reports Server (NTRS)

    Bohon, H. L.; Chapman, A. J., III; Leybold, H. A.

    1983-01-01

    The initial ground test of each component resulted in structural failure at less than ultimate design loads. While such failures represent major program delays, the investigation and analysis of each failure revealed significant lessons for effective utilization of composites in primary structure. Foremost among these are secondary loads that produce through-the-thickness forces which may lead to serious weaknesses in an otherwise sound structural design. The sources, magnitude, and effects of secondary loads need to be thoroughly understood and accounted for by the designers of composite primary aircraft structures.

  2. A variable structure approach to robust control of VTOL aircraft

    NASA Technical Reports Server (NTRS)

    Calise, A. J.; Kramer, F. S.

    1984-01-01

    This paper examines the application of variable structure control theory to the design of a flight control system for the AV-8A Harrier in a hover mode. The objective in variable structure design is to confine the state trajectories to a subspace of the total state space. The motion in this subspace is insensitive to system parameter variations and external disturbances that lie in the range space of the control. A switching type of control law results from the design procedure. The control system was designed to track a vector-valued velocity command. For comparison, a proportional controller was designed using optimal linear regulator theory. Both controllers were evaluated for their transient response performance using a linear model; then a nonlinear simulation study of a hovering approach to landing was conducted. The variable structure controller outperformed its linear counterpart in the presence of wind disturbances and plant parameter uncertainties afforded by the simulation.

  3. Compliant load-bearing skins and structures for morphing aircraft applications

    NASA Astrophysics Data System (ADS)

    Olympio, Kingnide Raymond

    Aircraft morphing has the potential to significantly improve the performance of an aircraft over its flight envelope and expand its ight capability to allow it to perform dramatically different missions. The multiple projects carried on in the past three decades have considerably helped improve the designing of actuation systems and the utilization of smart materials for morphing aircraft structures. However, morphing aircraft and especially aircraft undergoing large shape change still face some significant technical issues. Among them, the skin covering the morphing structure must meet challenging requirements that no current conventional material fully satisfy. The design of such skin, which should be able to undergo large deformations and to carry air-loads, has received some attention in the last several years but no satisfactory solution has been found yet. In the current study, the design of compliant cellular structures and flexible skins for morphing aircraft structures is investigated for two different morphing deformations. The first morphing deformation considered corresponds to one-dimensional morphing which is representative of a wing or blade changing its chord or span. The second morphing deformation considered is shear-compression morphing which can be found in some morphing wing undergoing change in area, sweep and chord such as NextGen Aeronautics' morphing wing. Topologies of compliant cellular structures which can be used for these two types of structures are first calculated using a multi-objective approach. These topologies are calculated based on linear kinematics but the effect of geometric nonlinearities is also investigated. Then, ways to provide a smooth surface were investigated by considering a general honeycomb substructure with infill, bonded face-sheet or scales. This allowed justifying an overall skin concept made of a cellular substructure with a bonded face-sheet. Lastly, the design of an improved skin for NextGen Aeronautics

  4. Macroscopic study of time unsteady noise of an aircraft engine during static tests

    NASA Technical Reports Server (NTRS)

    Clark, B. J.; Heidmann, M. F.; Kreim, W. J.

    1976-01-01

    Static tests of aircraft engines can exhibit greater than 10 db random unsteadiness of tone noise levels because flow disturbances that prevail near test site facilities are ingested. Presumably such changes are related to installation and test site features. Some properties of unsteady noise observed during tests of a Lycoming YF-102 turbofan engine are presented. Time and spatial variations in tone noise obtained from closely spaced far field and inlet duct microphones are displayed. Long to extremely short intermittent tone bursts are observed. Unsteadiness of the tone, its harmonics, and the broadband noise show little similarity. In the far field, identity of tone bursts is retained over a directivity angle of less than 10 deg. In the inlet duct, tone bursts appear to propagate axially but exhibit little circumferential similarity. They show only slight relationship to tone bursts observed in the far field. The results imply an intermittent generation of random mixtures of propagating duct modes.

  5. Aircraft wing structural detail design (wing, aileron, flaps, and subsystems)

    NASA Technical Reports Server (NTRS)

    Downs, Robert; Zable, Mike; Hughes, James; Heiser, Terry; Adrian, Kenneth

    1993-01-01

    The goal of this project was to design, in detail, the wing, flaps, and ailerons for a primary flight trainer. Integrated in this design are provisions for the fuel system, the electrical system, and the fuselage/cabin carry-through interface structure. This conceptual design displays the general arrangement of all major components in the wing structure, taking into consideration the requirements set forth by the appropriate sections of Federal Aviation Regulation Part 23 (FAR23) as well as those established in the statement of work.

  6. Synthesis of aircraft structures using integrated design and analysis methods

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, J.; Goetz, R. C.

    1978-01-01

    A systematic research is reported to develop and validate methods for structural sizing of an airframe designed with the use of composite materials and active controls. This research program includes procedures for computing aeroelastic loads, static and dynamic aeroelasticity, analysis and synthesis of active controls, and optimization techniques. Development of the methods is concerned with the most effective ways of integrating and sequencing the procedures in order to generate structural sizing and the associated active control system, which is optimal with respect to a given merit function constrained by strength and aeroelasticity requirements.

  7. Development of test methods for scale model simulation of aerial applications in the NASA Langley Vortex Research Facility. [agricultural aircraft

    NASA Technical Reports Server (NTRS)

    Jordan, F. L., Jr.

    1980-01-01

    As part of basic research to improve aerial applications technology, methods were developed at the Langley Vortex Research Facility to simulate and measure deposition patterns of aerially-applied sprays and granular materials by means of tests with small-scale models of agricultural aircraft and dynamically-scaled test particles. Interactions between the aircraft wake and the dispersed particles are being studied with the objective of modifying wake characteristics and dispersal techniques to increase swath width, improve deposition pattern uniformity, and minimize drift. The particle scaling analysis, test methods for particle dispersal from the model aircraft, visualization of particle trajectories, and measurement and computer analysis of test deposition patterns are described. An experimental validation of the scaling analysis and test results that indicate improved control of chemical drift by use of winglets are presented to demonstrate test methods.

  8. Imaging Ultrasonic Sensor System SWISS completed 60.000 simulated flight hours to check structural integrity of aircraft subcomponent

    NASA Astrophysics Data System (ADS)

    Kress, Klaus-Peter; Baderschneider, Hans J.; Guse, Guenther

    2003-08-01

    Many military platforms such as fighter aircraft are nowadays operated for several decades under sometimes varying missions. Additional requirements resulting from more severe fatigue spectra or extended life for these platforms may require additional means of ensuring structural integrity. It is then important to gain the maximum usage (fatigue life) of aircraft components most efficiently still ensuring structural integrity at all times. Conventional structural health monitoring systems are typically based on loads and usage monitoring. Together with modern non destructive damage detection techniques it could be possible to safely operate even aged platforms. This goal is achieved by periodic examinations in order to ensure that a structural item is free of damage. However, the dismantling of structures for the purpose of non destructive testing can be very costly, time intensive and sometimes harmful to the surrounding structure itself. Therefore integrated, reliable and affordable damage detection techniques are needed to avoid disassembly where economically or technically justified. Especially for well known hot spots an integrated damage sensor could provide an alternative solution to conventional procedures. SWISS (Smart Wide area Imaging Sensor System) is an ultrasonic imaging approach. A small sensor is permanently surface mounted on the component that is to be monitored. Typically the sensor is activated on ground and interrogated via cables that are built into the platform. These sensors facilitate the examination of the internal structure of a subcomponent. The ultrasonic beam is electronically controlled in order to scan the most critical areas from a fixed position. Functionality aspects as well as practicability issues of such a technology had to be addressed and solved. As a result of this study, simulated fatigue tests on a real complex fitting structure have proven the reliability of the imaging ultrasonic sensor under laboratory conditions for

  9. Analysis of an electrohydraulic aircraft control surface servo and comparison with test results

    NASA Technical Reports Server (NTRS)

    Edwards, J. W.

    1972-01-01

    An analysis of an electrohydraulic aircraft control-surface system is made in which the system is modeled as a lumped, two-mass, spring-coupled system controlled by a servo valve. Both linear and nonlinear models are developed, and the effects of hinge-moment loading are included. Transfer functions of the system and approximate literal factors of the transfer functions for several cases are presented. The damping action of dynamic pressure feedback is analyzed. Comparisons of the model responses with results from tests made on a highly resonant rudder control-surface servo indicate the adequacy of the model. The effects of variations in hinge-moment loading are illustrated.

  10. Tidewater and Weather-exposure Tests on Metals Used in Aircraft II.

    NASA Technical Reports Server (NTRS)

    Mutchler, Willard; Galvin, W G

    1942-01-01

    This report is an addendum to NACA Technical Note No. 736, which dealt with tidewater and weather-exposure tests being conducted by the National Bureau of Standards on various aluminum alloys, magnesium alloys, and stainless steels used in aircraft. The exposures were begun in June 1938 and were terminated, for this particular series, in June 1941. The methods of exposure and the materials being investigated are described, and the more important results obtained up to the conclusion of the second year's exposure are reported.

  11. Assessment System for Aircraft Noise (ASAN): Development of alpha-test prototype system software

    NASA Astrophysics Data System (ADS)

    Reddingius, Nicholaas H.; Smyth, John S.

    1990-02-01

    The Alpha-Test version of the Assessment System for Aircraft Noise (ASAN) is described. ASAN was developed for the United States Air Force's Noise and Sonic Boom Impact Technology Advanced Development Program Office (NSBIT ADPO). The Purpose of ASAN is to provide Air Force route and environmental planners with a set of tools for preparing the noise portion of environmental impact statements (EIS), environmental assessments (EA), and findings of no significant impact (FONSI). ASAN provides a consistent set of procedures and models which represent the current state-of-the-art in noise engineering practice. A brief overview is given of the technical issues of developing the ASAN system.

  12. The 1991 International Conference on Aging Aircraft and Structural Airworthiness

    NASA Technical Reports Server (NTRS)

    Harris, Charles E. (Editor)

    1992-01-01

    Technical sessions of the conference included structural performance, nondestructive evaluation, maintenance and repair, international activities, and commuter airlines. Each session was organized to provide a well-rounded view of the subject from the industry, regulatory, and research perspective. Thirty-four presentations were given by the international technical community.

  13. V/STOL tilt rotor aircraft study: Wind tunnel tests of a full scale hingeless prop/rotor designed for the Boeing Model 222 tilt rotor aircraft

    NASA Technical Reports Server (NTRS)

    Magee, J. P.; Alexander, H. R.

    1973-01-01

    The rotor system designed for the Boeing Model 222 tilt rotor aircraft is a soft-in-plane hingeless rotor design, 26 feet in diameter. This rotor has completed two test programs in the NASA Ames 40' X 80' wind tunnel. The first test was a windmilling rotor test on two dynamic wing test stands. The rotor was tested up to an advance ratio equivalence of 400 knots. The second test used the NASA powered propeller test rig and data were obtained in hover, transition and low speed cruise flight. Test data were obtained in the areas of wing-rotor dynamics, rotor loads, stability and control, feedback controls, and performance to meet the test objectives. These data are presented.

  14. Integrated Flight/Structural Mode Control for Very Flexible Aircraft Using L1 Adaptive Output Feedback Controller

    NASA Technical Reports Server (NTRS)

    Che, Jiaxing; Cao, Chengyu; Gregory, Irene M.

    2012-01-01

    This paper explores application of adaptive control architecture to a light, high-aspect ratio, flexible aircraft configuration that exhibits strong rigid body/flexible mode coupling. Specifically, an L(sub 1) adaptive output feedback controller is developed for a semi-span wind tunnel model capable of motion. The wind tunnel mount allows the semi-span model to translate vertically and pitch at the wing root, resulting in better simulation of an aircraft s rigid body motion. The control objective is to design a pitch control with altitude hold while suppressing body freedom flutter. The controller is an output feedback nominal controller (LQG) augmented by an L(sub 1) adaptive loop. A modification to the L(sub 1) output feedback is proposed to make it more suitable for flexible structures. The new control law relaxes the required bounds on the unmatched uncertainty and allows dependence on the state as well as time, i.e. a more general unmatched nonlinearity. The paper presents controller development and simulated performance responses. Simulation is conducted by using full state flexible wing models derived from test data at 10 different dynamic pressure conditions. An L(sub 1) adaptive output feedback controller is designed for a single test point and is then applied to all the test cases. The simulation results show that the L(sub 1) augmented controller can stabilize and meet the performance requirements for all 10 test conditions ranging from 30 psf to 130 psf dynamic pressure.

  15. Flight testing a propulsion-controlled aircraft emergency flight control system on an F-15 airplane

    NASA Technical Reports Server (NTRS)

    Burcham, F. W., Jr.; Burken, John; Maine, Trindel A.

    1994-01-01

    Flight tests of a propulsion-controlled aircraft (PCA) system on an F-15 airplane have been conducted at the NASA Dryden Flight Research Center. The airplane was flown with all flight control surfaces locked both in the manual throttles-only mode and in an augmented system mode. In the latter mode, pilot thumbwheel commands and aircraft feedback parameters were used to position the throttles. Flight evaluation results showed that the PCA system can be used to land an airplane that has suffered a major flight control system failure safely. The PCA system was used to recover the F-15 airplane from a severe upset condition, descend, and land. Pilots from NASA, U.S. Air Force, U.S. Navy, and McDonnell Douglas Aerospace evaluated the PCA system and were favorably impressed with its capability. Manual throttles-only approaches were unsuccessful. This paper describes the PCA system operation and testing. It also presents flight test results and pilot comments.

  16. Estimation of Handling Qualities Parameters of the Tu-144 Supersonic Transport Aircraft from Flight Test Data

    NASA Technical Reports Server (NTRS)

    Curry, Timothy J.; Batterson, James G. (Technical Monitor)

    2000-01-01

    Low order equivalent system (LOES) models for the Tu-144 supersonic transport aircraft were identified from flight test data. The mathematical models were given in terms of transfer functions with a time delay by the military standard MIL-STD-1797A, "Flying Qualities of Piloted Aircraft," and the handling qualities were predicted from the estimated transfer function coefficients. The coefficients and the time delay in the transfer functions were estimated using a nonlinear equation error formulation in the frequency domain. Flight test data from pitch, roll, and yaw frequency sweeps at various flight conditions were used for parameter estimation. Flight test results are presented in terms of the estimated parameter values, their standard errors, and output fits in the time domain. Data from doublet maneuvers at the same flight conditions were used to assess the predictive capabilities of the identified models. The identified transfer function models fit the measured data well and demonstrated good prediction capabilities. The Tu-144 was predicted to be between level 2 and 3 for all longitudinal maneuvers and level I for all lateral maneuvers. High estimates of the equivalent time delay in the transfer function model caused the poor longitudinal rating.

  17. NASA rotor systems research aircraft: Fixed-wing configuration flight-test results

    NASA Technical Reports Server (NTRS)

    Erickson, R. E.; Cross, J. L.; Kufeld, R. M.; Acree, C. W.; Nguyen, D.; Hodge, R. W.

    1986-01-01

    The fixed-wing, airplane configuration flight-test results of the Rotor System Research Aircraft (RSRA), NASA 740, at Ames/Dryden Flight Research Center are documented. Fourteen taxi and flight tests were performed from December 1983 to October 1984. This was the first time the RSRA was flown with the main rotor removed; the tail rotor was installed. These tests confirmed that the RSRA is operable as a fixed-wing aircraft. Data were obtained for various takeoff and landing distances, control sensitivity, trim and dynamics stability characteristics, performance rotor-hub drag, and acoustics signature. Stability data were obtained with the rotor hub both installed and removed. The speed envelope was developed to 261 knots true airspeed (KTAS), 226 knots calibrated airspeed (KCAS) at 10,000 ft density altitude. The airplane was configured at 5 deg. wing incidence with 5 deg. wing flaps as a normal configuration. Level-flight data were acquired at 167 KCAS for wing incidence from 0 to 10 deg. Step inputs and doublet inputs of various magnitudes were utilized to acquire dynamic stability and control sensitivity data. Sine-wave inputs of constantly increasing frequency were used to generate parameter identification data. The maximum load factor attained was 2.34 g at 206 KCAS.

  18. A History of Full-Scale Aircraft and Rotorcraft Crash Testing and Simulation at NASA Langley Research Center

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.; Lyle, Karen H.

    2004-01-01

    This paper summarizes 2-1/2 decades of full-scale aircraft and rotorcraft crash testing performed at the Impact Dynamics Research Facility (IDRF) located at NASA Langley Research Center in Hampton, Virginia. The IDRF is a 240-ft.-high steel gantry that was built originally as a lunar landing simulator facility in the early 1960's. It was converted into a full-scale crash test facility for light aircraft and rotorcraft in the early 1970 s. Since the first full-scale crash test was preformed in February 1974, the IDRF has been used to conduct: 41 full-scale crash tests of General Aviation (GA) aircraft including landmark studies to establish baseline crash performance data for metallic and composite GA aircraft; 11 full-scale crash tests of helicopters including crash qualification tests of the Bell and Sikorsky Advanced Composite Airframe Program (ACAP) prototypes; 48 Wire Strike Protection System (WSPS) qualification tests of Army helicopters; 3 vertical drop tests of Boeing 707 transport aircraft fuselage sections; and, 60+ crash tests of the F-111 crew escape module. For some of these tests, nonlinear transient dynamic codes were utilized to simulate the impact response of the airframe. These simulations were performed to evaluate the capabilities of the analytical tools, as well as to validate the models through test-analysis correlation. In September 2003, NASA Langley closed the IDRF facility and plans are underway to demolish it in 2007. Consequently, it is important to document the contributions made to improve the crashworthiness of light aircraft and rotorcraft achieved through full-scale crash testing and simulation at the IDRF.

  19. Control Design Strategies to Enhance Long-Term Aircraft Structural Integrity

    NASA Technical Reports Server (NTRS)

    Newman, Brett A.

    1999-01-01

    Over the operational lifetime of both military and civil aircraft, structural components are exposed to hundreds of thousands of low-stress repetitive load cycles and less frequent but higher-stress transient loads originating from maneuvering flight and atmospheric gusts. Micro-material imperfections in the structure, such as cracks and debonded laminates, expand and grow in this environment, reducing the structural integrity and shortening the life of the airframe. Extreme costs associated with refurbishment of critical load-bearing structural components in a large fleet, or altogether reinventoring the fleet with newer models, indicate alternative solutions for life extension of the airframe structure are highly desirable. Increased levels of operational safety and reliability are also important factors influencing the desirability of such solutions. One area having significant potential for impacting crack growth/fatigue damage reduction and structural life extension is flight control. To modify the airframe response dynamics arising from command inputs and gust disturbances, feedback loops are routinely applied to vehicles. A dexterous flight control system architecture senses key vehicle motions and generates critical forces/moments at multiple points distributed throughout the airframe to elicit the desired motion characteristics. In principle, these same control loops can be utilized to influence the level of exposure to harmful loads during flight on structural components. Project objectives are to investigate and/or assess the leverage control has on reducing fatigue damage and enhancing long-term structural integrity, without degrading attitude control and trajectory guidance performance levels. In particular, efforts have focused on the effects inner loop control parameters and architectures have on fatigue damage rate. To complete this research, an actively controlled flexible aircraft model and a new state space modeling procedure for crack growth

  20. Supersonic cruise research aircraft structural studies: Methods and results

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, J.; Gross, D.; Kurtze, W.; Newsom, J.; Wrenn, G.; Greene, W.

    1981-01-01

    NASA Langley Research Center SCAR in-house structural studies are reviewed. In methods development, advances include a new system of integrated computer programs called ISSYS, progress in determining aerodynamic loads and aerodynamically induced structural loads (including those due to gusts), flutter optimization for composite and metal airframe configurations using refined and simplified mathematical models, and synthesis of active controls. Results given address several aspects of various SCR configurations. These results include flutter penalties on composite wing, flutter suppression using active controls, roll control effectiveness, wing tip ground clearance, tail size effect on flutter, engine weight and mass distribution influence on flutter, and strength and flutter optimization of new configurations. The ISSYS system of integrated programs performed well in all the applications illustrated by the results, the diversity of which attests to ISSYS' versatility.