76 FR 35912 - Business Jet Aircraft Industry: Structure and Factors Affecting Competitiveness; Institution of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-20

... INTERNATIONAL TRADE COMMISSION [Investigation No. 332-526] Business Jet Aircraft Industry... International Trade Commission (Commission) instituted investigation No. 332-526, Business Jet Aircraft Industry... competitiveness of the business jet aircraft industry in the United States, Brazil, Canada, Europe, and China. To...

Industrial point source CO2 emission strength estimation with aircraft measurements and dispersion modelling.

PubMed

Carotenuto, Federico; Gualtieri, Giovanni; Miglietta, Franco; Riccio, Angelo; Toscano, Piero; Wohlfahrt, Georg; Gioli, Beniamino

2018-02-22

CO 2 remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO 2 emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO 2 industrial point source, located in Biganos, France. CO 2 density measurements were obtained by applying the mass balance method, while CO 2 emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.

Titanium fasteners. [for aircraft industry

NASA Technical Reports Server (NTRS)

Phillips, J. L.

1972-01-01

Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

An economic model of the manufacturers' aircraft production and airline earnings potential, volume 3

NASA Technical Reports Server (NTRS)

Kneafsey, J. T.; Hill, R. M.

1978-01-01

A behavioral explanation of the process of technological change in the U. S. aircraft manufacturing and airline industries is presented. The model indicates the principal factors which influence the aircraft (airframe) manufacturers in researching, developing, constructing and promoting new aircraft technology; and the financial requirements which determine the delivery of new aircraft to the domestic trunk airlines. Following specification and calibration of the model, the types and numbers of new aircraft were estimated historically for each airline's fleet. Examples of possible applications of the model to forecasting an individual airline's future fleet also are provided. The functional form of the model is a composite which was derived from several preceding econometric models developed on the foundations of the economics of innovation, acquisition, and technological change and represents an important contribution to the improved understanding of the economic and financial requirements for aircraft selection and production. The model's primary application will be to forecast the future types and numbers of new aircraft required for each domestic airline's fleet.

Modeling of Wake-vortex Aircraft Encounters. Appendix B

NASA Technical Reports Server (NTRS)

Smith, Sonya T.

1999-01-01

There are more people passing through the world's airports today than at any other time in history. With this increase in civil transport, airports are becoming capacity limited. In order to increase capacity and thus meet the demands of the flying public, the number of runways and number of flights per runway must be increased. In response to the demand, the National Aeronautics and Space Administration (NASA), in conjunction with the Federal Aviation Administration (FAA), airport operators, and the airline industry are taking steps to increase airport capacity without jeopardizing safety. Increasing the production per runway increases the likelihood that an aircraft will encounter the trailing wake-vortex of another aircraft. The hazard of a wake-vortex encounter is that heavy load aircraft can produce high intensity wake turbulence, through the development of its wing-tip vortices. A smaller aircraft following in the wake of the heavy load aircraft will experience redistribution of its aerodynamic load. This creates a safety hazard for the smaller aircraft. Understanding this load redistribution is of great importance, particularly during landing and take-off. In this research wake-vortex effects on an encountering 10% scale model of the B737-100 aircraft are modeled using both strip theory and vortex-lattice modeling methods. The models are then compared to wind tunnel data that was taken in the 30ft x 60ft wind tunnel at NASA Langley Research Center (LaRC). Comparisons are made to determine if the models will have acceptable accuracy when parts of the geometry are removed, such as the horizontal stabilizer and the vertical tail. A sensitivity analysis was also performed to observe how accurately the models could match the experimental data if there was a 10% error in the circulation strength. It was determined that both models show accurate results when the wing, horizontal stabilizer, and vertical tail were a part of the geometry. When the horizontal

Dimensional measuring techniques in the automotive and aircraft industry

NASA Astrophysics Data System (ADS)

Muench, K. H.; Baertlein, Hugh

1994-03-01

Optical tooling methods used in industry are rapidly being replaced by new electronic sensor techniques. The impact of new measuring technologies on the production process has caused major changes on the industrial shop floor as well as within industrial measurement systems. The paper deals with one particular industrial measuring system, the manual theodolite measuring system (TMS), within the aircraft and automobile industry. With TMS, setup, data capture, and data analysis are flexible enough to suit industry's demands regarding speed, accuracy, and mobility. Examples show the efficiency and the wide range of TMS applications. In cooperation with industry, the Video Theodolite System was developed. Its origin, functions, capabilities, and future plans are briefly described. With the VTS a major step has been realized in direction to vision systems for industrial applications.

Structural modeling of aircraft tires

NASA Technical Reports Server (NTRS)

Clark, S. K.; Dodge, R. N.; Lackey, J. I.; Nybakken, G. H.

1973-01-01

A theoretical and experimental investigation of the feasibility of determining the mechanical properties of aircraft tires from small-scale model tires was accomplished. The theoretical results indicate that the macroscopic static and dynamic mechanical properties of aircraft tires can be accurately determined from the scale model tires although the microscopic and thermal properties of aircraft tires can not. The experimental investigation was conducted on a scale model of a 40 x 12, 14 ply rated, type 7 aircraft tire with a scaling factor of 8.65. The experimental results indicate that the scale model tire exhibited the same static mechanical properties as the prototype tire when compared on a dimensionless basis. The structural modeling concept discussed in this report is believed to be exact for mechanical properties of aircraft tires under static, rolling, and transient conditions.

76 FR 78328 - Access to Aircraft Situation Display to Industry (ASDI) and National Airspace System Status...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-16

... owner's or operator's aircraft registration number from any display of the [FAA's ASDI] data that is... the registration number of the aircraft, whether the requestor is an owner or operator of the aircraft... Aircraft Situation Display to Industry (ASDI) and National Airspace System Status Information (NASSI) Data...

Aircraft cockpit vision: Math model

NASA Technical Reports Server (NTRS)

Bashir, J.; Singh, R. P.

1975-01-01

A mathematical model was developed to describe the field of vision of a pilot seated in an aircraft. Given the position and orientation of the aircraft, along with the geometrical configuration of its windows, and the location of an object, the model determines whether the object would be within the pilot's external vision envelope provided by the aircraft's windows. The computer program using this model was implemented and is described.

Automatic non-destructive system for quality assurance of welded elements in the aircraft industry

NASA Astrophysics Data System (ADS)

Chady, Tomasz; Waszczuk, Paweł; Szydłowski, Michał; Szwagiel, Mariusz

2018-04-01

Flaws that might be a result of the welding process have to be detected, in order to assure high quality thus reliability of elements exploited in aircraft industry. Currently the inspection stage is conducted manually by a qualified workforce. There are no commercially available systems that could support or replace humans in the flaw detection process. In this paper authors present a novel non-destructive system developed for quality assurance purposes of welded elements utilized in the aircraft industry.

78 FR 57104 - Airworthiness Directives; Diamond Aircraft Industries Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-17

... condition as fatigue strength found in the aft main spar does not ensure unlimited lifetime structural... Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590, between 9 a.m. and 5... proposed AD, contact Diamond Aircraft Industries GmbH, N.A. Otto-Str.5, A-2700 Wiener Neustadt, Austria...

Numerical continuation and bifurcation analysis in aircraft design: an industrial perspective.

PubMed

Sharma, Sanjiv; Coetzee, Etienne B; Lowenberg, Mark H; Neild, Simon A; Krauskopf, Bernd

2015-09-28

Bifurcation analysis is a powerful method for studying the steady-state nonlinear dynamics of systems. Software tools exist for the numerical continuation of steady-state solutions as parameters of the system are varied. These tools make it possible to generate 'maps of solutions' in an efficient way that provide valuable insight into the overall dynamic behaviour of a system and potentially to influence the design process. While this approach has been employed in the military aircraft control community to understand the effectiveness of controllers, the use of bifurcation analysis in the wider aircraft industry is yet limited. This paper reports progress on how bifurcation analysis can play a role as part of the design process for passenger aircraft. © 2015 The Author(s).

General Aviation Aircraft Utilization in the Construction Industry.

DTIC Science & Technology

1987-01-01

York), Vol.45, no.11, Nov 1975, pg 82-86 6. Hinze, Jimmie and Pannullo, John 1978 "Safety; Function of Job Control" Journal of the Construction...Long, Daniel S., Taylor, John E. and McCarthy, Jack 1986 "Cessna Aircraft Cabin Door Mount for Photographic and Videographic Cameras" Photogrammetric...PIKE INDUSTRIES RD #2 BOX 91 CHILTON NH 03276 ARTHUR WHITCOMB INC BOX 747 KEENE NH 03431 SCHIAVONE CONSTR CO BOX 1179 SECAUCUS N,, 07094 J. W. JOES 8800

77 FR 50954 - Airworthiness Directives; Cessna Aircraft Company

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-23

... Company (Cessna) Model 402C airplanes modified by Sierra Industries, Ltd. Supplemental Type Certificate... Airworthiness Directives; Cessna Aircraft Company AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... earlier proposed airworthiness directive (AD) for all Cessna Aircraft Company (Cessna) Model 402C...

Aircraft system modeling error and control error

NASA Technical Reports Server (NTRS)

Kulkarni, Nilesh V. (Inventor); Kaneshige, John T. (Inventor); Krishnakumar, Kalmanje S. (Inventor); Burken, John J. (Inventor)

2012-01-01

A method for modeling error-driven adaptive control of an aircraft. Normal aircraft plant dynamics is modeled, using an original plant description in which a controller responds to a tracking error e(k) to drive the component to a normal reference value according to an asymptote curve. Where the system senses that (1) at least one aircraft plant component is experiencing an excursion and (2) the return of this component value toward its reference value is not proceeding according to the expected controller characteristics, neural network (NN) modeling of aircraft plant operation may be changed. However, if (1) is satisfied but the error component is returning toward its reference value according to expected controller characteristics, the NN will continue to model operation of the aircraft plant according to an original description.

Computing Linear Mathematical Models Of Aircraft

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Antoniewicz, Robert F.; Krambeer, Keith D.

1991-01-01

Derivation and Definition of Linear Aircraft Model (LINEAR) computer program provides user with powerful, and flexible, standard, documented, and verified software tool for linearization of mathematical models of aerodynamics of aircraft. Intended for use in software tool to drive linear analysis of stability and design of control laws for aircraft. Capable of both extracting such linearized engine effects as net thrust, torque, and gyroscopic effects, and including these effects in linear model of system. Designed to provide easy selection of state, control, and observation variables used in particular model. Also provides flexibility of allowing alternate formulations of both state and observation equations. Written in FORTRAN.

76 FR 19903 - Special Conditions: Diamond Aircraft Industry Model DA-40NG; Diesel Cycle Engine

Federal Register 2010, 2011, 2012, 2013, 2014

2011-04-11

... DA-40NG the Austro Engine GmbH model E4 aircraft diesel engine (ADE) using turbine (jet) fuel. This... engine utilizing turbine (jet) fuel. The applicable airworthiness regulations do not contain adequate or...: Installation of the Austro Engine GmbH Model E4 ADE diesel engine utilizing turbine (jet) fuel. Discussion...

Advanced simulation noise model for modern fighter aircraft

NASA Astrophysics Data System (ADS)

Ikelheimer, Bruce

2005-09-01

NoiseMap currently represents the state of the art for military airfield noise analysis. While this model is sufficient for the current fleet of aircraft, it has limits in its capability to model the new generation of fighter aircraft like the JSF and the F-22. These aircraft's high-powered engines produce noise with significant nonlinear content. Combining this with their ability to vector the thrust means they have noise characteristics that are outside of the basic modeling assumptions of the currently available noise models. Wyle Laboratories, Penn State University, and University of Alabama are in the process of developing a new noise propagation model for the Strategic Environmental Research and Development Program. Source characterization will be through complete spheres (or hemispheres if there is not sufficient data) for each aircraft state (including thrust vector angles). Fixed and rotor wing aircraft will be included. Broadband, narrowband, and pure tone propagation will be included. The model will account for complex terrain and weather effects, as well as the effects of nonlinear propagation. It will be a complete model capable of handling a range of noise sources from small subsonic general aviation aircraft to the latest fighter aircraft like the JSF.

Aircraft Dynamic Modeling in Turbulence

NASA Technical Reports Server (NTRS)

Morelli, Eugene A.; Cunninham, Kevin

2012-01-01

A method for accurately identifying aircraft dynamic models in turbulence was developed and demonstrated. The method uses orthogonal optimized multisine excitation inputs and an analytic method for enhancing signal-to-noise ratio for dynamic modeling in turbulence. A turbulence metric was developed to accurately characterize the turbulence level using flight measurements. The modeling technique was demonstrated in simulation, then applied to a subscale twin-engine jet transport aircraft in flight. Comparisons of modeling results obtained in turbulent air to results obtained in smooth air were used to demonstrate the effectiveness of the approach.

Aircraft vulnerability analysis by modeling and simulation

NASA Astrophysics Data System (ADS)

Willers, Cornelius J.; Willers, Maria S.; de Waal, Alta

2014-10-01

Infrared missiles pose a significant threat to civilian and military aviation. ManPADS missiles are especially dangerous in the hands of rogue and undisciplined forces. Yet, not all the launched missiles hit their targets; the miss being either attributable to misuse of the weapon or to missile performance restrictions. This paper analyses some of the factors affecting aircraft vulnerability and demonstrates a structured analysis of the risk and aircraft vulnerability problem. The aircraft-missile engagement is a complex series of events, many of which are only partially understood. Aircraft and missile designers focus on the optimal design and performance of their respective systems, often testing only in a limited set of scenarios. Most missiles react to the contrast intensity, but the variability of the background is rarely considered. Finally, the vulnerability of the aircraft depends jointly on the missile's performance and the doctrine governing the missile's launch. These factors are considered in a holistic investigation. The view direction, altitude, time of day, sun position, latitude/longitude and terrain determine the background against which the aircraft is observed. Especially high gradients in sky radiance occur around the sun and on the horizon. This paper considers uncluttered background scenes (uniform terrain and clear sky) and presents examples of background radiance at all view angles across a sphere around the sensor. A detailed geometrical and spatially distributed radiometric model is used to model the aircraft. This model provides the signature at all possible view angles across the sphere around the aircraft. The signature is determined in absolute terms (no background) and in contrast terms (with background). It is shown that the background significantly affects the contrast signature as observed by the missile sensor. A simplified missile model is constructed by defining the thrust and mass profiles, maximum seeker tracking rate, maximum

Airborne Subscale Transport Aircraft Research Testbed: Aircraft Model Development

NASA Technical Reports Server (NTRS)

Jordan, Thomas L.; Langford, William M.; Hill, Jeffrey S.

2005-01-01

The Airborne Subscale Transport Aircraft Research (AirSTAR) testbed being developed at NASA Langley Research Center is an experimental flight test capability for research experiments pertaining to dynamics modeling and control beyond the normal flight envelope. An integral part of that testbed is a 5.5% dynamically scaled, generic transport aircraft. This remotely piloted vehicle (RPV) is powered by twin turbine engines and includes a collection of sensors, actuators, navigation, and telemetry systems. The downlink for the plane includes over 70 data channels, plus video, at rates up to 250 Hz. Uplink commands for aircraft control include over 30 data channels. The dynamic scaling requirement, which includes dimensional, weight, inertial, actuator, and data rate scaling, presents distinctive challenges in both the mechanical and electrical design of the aircraft. Discussion of these requirements and their implications on the development of the aircraft along with risk mitigation strategies and training exercises are included here. Also described are the first training (non-research) flights of the airframe. Additional papers address the development of a mobile operations station and an emulation and integration laboratory.

Model of aircraft noise adaptation

NASA Technical Reports Server (NTRS)

Dempsey, T. K.; Coates, G. D.; Cawthorn, J. M.

1977-01-01

Development of an aircraft noise adaptation model, which would account for much of the variability in the responses of subjects participating in human response to noise experiments, was studied. A description of the model development is presented. The principal concept of the model, was the determination of an aircraft adaptation level which represents an annoyance calibration for each individual. Results showed a direct correlation between noise level of the stimuli and annoyance reactions. Attitude-personality variables were found to account for varying annoyance judgements.

A NASA/University/Industry Consortium for Research on Aircraft Ice Protection

NASA Technical Reports Server (NTRS)

Zumwalt, Glen W.

1989-01-01

From 1982 through 1987, an unique consortium was functioning which involved government (NASA), academia (Wichita State Univ.) and twelve industries. The purpose was the development of a better ice protection systems for aircraft. The circumstances which brought about this activity are described, the formation and operation recounted, and the effectiveness of the ventue evaluated.

Cobalt: A vital element in the aircraft engine industry

NASA Technical Reports Server (NTRS)

Stephens, J. R.

1981-01-01

Recent trends in the United States consumption of cobalt indicate that superalloys for aircraft engine manufacture require increasing amounts of this strategic element. Superalloys consume a lion's share of total U.S. cobalt usage which was about 16 million pounds in 1980. In excess of 90 percent of the cobalt used in this country was imported, principally from the African countries of Zaire and Zambia. Early studies on the roles of cobalt as an alloying element in high temperature alloys concentrated on the simple Ni-Cr and Nimonic alloy series. The role of cobalt in current complex nickel base superalloys is not well defined and indeed, the need for the high concentration of cobalt in widely used nickel base superalloys is not firmly established. The current cobalt situation is reviewed as it applies to superalloys and the opportunities for research to reduce the consumption of cobalt in the aircraft engine industry are described.

Review of Idealized Aircraft Wake Vortex Models

NASA Technical Reports Server (NTRS)

Ahmad, Nashat N.; Proctor, Fred H.; Duparcmeur, Fanny M. Limon; Jacob, Don

2014-01-01

Properties of three aircraft wake vortex models, Lamb-Oseen, Burnham-Hallock, and Proctor are reviewed. These idealized models are often used to initialize the aircraft wake vortex pair in large eddy simulations and in wake encounter hazard models, as well as to define matched filters for processing lidar observations of aircraft wake vortices. Basic parameters for each vortex model, such as peak tangential velocity and circulation strength as a function of vortex core radius size, are examined. The models are also compared using different vortex characterizations, such as the vorticity magnitude. Results of Euler and large eddy simulations are presented. The application of vortex models in the postprocessing of lidar observations is discussed.

An aircraft noise pollution model for trajectory optimization

NASA Technical Reports Server (NTRS)

Barkana, A.; Cook, G.

1976-01-01

A mathematical model describing the generation of aircraft noise is developed with the ultimate purpose of reducing noise (noise-optimizing landing trajectories) in terminal areas. While the model is for a specific aircraft (Boeing 737), the methodology would be applicable to a wide variety of aircraft. The model is used to obtain a footprint on the ground inside of which the noise level is at or above 70 dB.

NASA/Army Rotorcraft Technology. Volume 3: Systems Integration, Research Aircraft, and Industry

NASA Technical Reports Server (NTRS)

1988-01-01

This is part 3 of the conference proceedings on rotorcraft technology. This volume is divided into areas on systems integration, research aircraft, and industry. Representative titles from each area are: system analysis in rotorcraft design, the past decade; rotorcraft flight research with emphasis on rotor systems; and an overview of key technology thrusts at Bell Helicopter Textron.

An improved source model for aircraft interior noise studies

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Fuller, C. R.

1985-01-01

There is concern that advanced turboprop engines currently being developed may produce excessive aircraft cabin noise levels. This concern has stimulated renewed interest in developing aircraft interior noise reduction methods that do not significantly increase take off weight. An existing analytical model for noise transmission into aircraft cabins was utilized to investigate the behavior of an improved propeller source model for use in aircraft interior noise studies. The new source model, a virtually rotating dipole, is shown to adequately match measured fuselage sound pressure distributions, including the correct phase relationships, for published data. The virtually rotating dipole is used to study the sensitivity of synchrophasing effectiveness to the fuselage sound pressure trace velocity distribution. Results of calculations are presented which reveal the importance of correctly modeling the surface pressure phase relations in synchrophasing and other aircraft interior noise studies.

An improved source model for aircraft interior noise studies

NASA Technical Reports Server (NTRS)

Mahan, J. R.; Fuller, C. R.

1985-01-01

There is concern that advanced turboprop engines currently being developed may produce excessive aircraft cabin noise level. This concern has stimulated renewed interest in developing aircraft interior noise reduction methods that do not significnatly increase take off weight. An existing analytical model for noise transmission into aircraft cabins was utilized to investigate the behavior of an improved propeller source model for use in aircraft interior noise studies. The new source model, a virtually rotating dipole, is shown to adequately match measured fuselage sound pressure distributions, including the correct phase relationships, for published data. The virtually rotating dipole is used to study the sensitivity of synchrophasing effectiveness to the fuselage sound pressure trace velocity distribution. Results of calculations are presented which reveal the importance of correctly modeling the surface pressure phase relations in synchrophasing and other aircraft interior noise studies.

Modeling aircraft noise induced sleep disturbance

NASA Astrophysics Data System (ADS)

McGuire, Sarah M.

One of the primary impacts of aircraft noise on a community is its disruption of sleep. Aircraft noise increases the time to fall asleep, the number of awakenings, and decreases the amount of rapid eye movement and slow wave sleep. Understanding these changes in sleep may be important as they could increase the risk for developing next-day effects such as sleepiness and reduced performance and long-term health effects such as cardiovascular disease. There are models that have been developed to predict the effect of aircraft noise on sleep. However, most of these models only predict the percentage of the population that is awakened. Markov and nonlinear dynamic models have been developed to predict an individual's sleep structure during the night. However, both of these models have limitations. The Markov model only accounts for whether an aircraft event occurred not the noise level or other sound characteristics of the event that may affect the degree of disturbance. The nonlinear dynamic models were developed to describe normal sleep regulation and do not have a noise effects component. In addition, the nonlinear dynamic models have slow dynamics which make it difficult to predict short duration awakenings which occur both spontaneously and as a result of nighttime noise exposure. The purpose of this research was to examine these sleep structure models to determine how they could be altered to predict the effect of aircraft noise on sleep. Different approaches for adding a noise level dependence to the Markov Model was explored and the modified model was validated by comparing predictions to behavioral awakening data. In order to determine how to add faster dynamics to the nonlinear dynamic sleep models it was necessary to have a more detailed sleep stage classification than was available from visual scoring of sleep data. An automatic sleep stage classification algorithm was developed which extracts different features of polysomnography data including the

Modeling Programs Increase Aircraft Design Safety

NASA Technical Reports Server (NTRS)

2012-01-01

Flutter may sound like a benign word when associated with a flag in a breeze, a butterfly, or seaweed in an ocean current. When used in the context of aerodynamics, however, it describes a highly dangerous, potentially deadly condition. Consider the case of the Lockheed L-188 Electra Turboprop, an airliner that first took to the skies in 1957. Two years later, an Electra plummeted to the ground en route from Houston to Dallas. Within another year, a second Electra crashed. In both cases, all crew and passengers died. Lockheed engineers were at a loss as to why the planes wings were tearing off in midair. For an answer, the company turned to NASA s Transonic Dynamics Tunnel (TDT) at Langley Research Center. At the time, the newly renovated wind tunnel offered engineers the capability of testing aeroelastic qualities in aircraft flying at transonic speeds near or just below the speed of sound. (Aeroelasticity is the interaction between aerodynamic forces and the structural dynamics of an aircraft or other structure.) Through round-the-clock testing in the TDT, NASA and industry researchers discovered the cause: flutter. Flutter occurs when aerodynamic forces acting on a wing cause it to vibrate. As the aircraft moves faster, certain conditions can cause that vibration to multiply and feed off itself, building to greater amplitudes until the flutter causes severe damage or even the destruction of the aircraft. Flutter can impact other structures as well. Famous film footage of the Tacoma Narrows Bridge in Washington in 1940 shows the main span of the bridge collapsing after strong winds generated powerful flutter forces. In the Electra s case, faulty engine mounts allowed a type of flutter known as whirl flutter, generated by the spinning propellers, to transfer to the wings, causing them to vibrate violently enough to tear off. Thanks to the NASA testing, Lockheed was able to correct the Electra s design flaws that led to the flutter conditions and return the

Infrared Signature Modeling and Analysis of Aircraft Plume

NASA Astrophysics Data System (ADS)

Rao, Arvind G.

2011-09-01

In recent years, the survivability of an aircraft has been put to task more than ever before. One of the main reasons is the increase in the usage of Infrared (IR) guided Anti-Aircraft Missiles, especially due to the availability of Man Portable Air Defence System (MANPADS) with some terrorist groups. Thus, aircraft IR signatures are gaining more importance as compared to their radar, visual, acoustic, or any other signatures. The exhaust plume ejected from the aircraft is one of the important sources of IR signature in military aircraft that use low bypass turbofan engines for propulsion. The focus of the present work is modelling of spectral IR radiation emission from the exhaust jet of a typical military aircraft and to evaluate the aircraft susceptibility in terms of the aircraft lock-on range due to its plume emission, for a simple case against a typical Surface to Air Missile (SAM). The IR signature due to the aircraft plume is examined in a holistic manner. A comprehensive methodology of computing IR signatures and its affect on aircraft lock-on range is elaborated. Commercial CFD software has been used to predict the plume thermo-physical properties and subsequently an in-house developed code was used for evaluating the IR radiation emitted by the plume. The LOWTRAN code has been used for modeling the atmospheric IR characteristics. The results obtained from these models are in reasonable agreement with some available experimental data. The analysis carried out in this paper succinctly brings out the intricacy of the radiation emitted by various gaseous species in the plume and the role of atmospheric IR transmissivity in dictating the plume IR signature as perceived by an IR guided SAM.

Dynamic Modeling, Controls, and Testing for Electrified Aircraft

NASA Technical Reports Server (NTRS)

Connolly, Joseph; Stalcup, Erik

2017-01-01

Electrified aircraft have the potential to provide significant benefits for efficiency and emissions reductions. To assess these potential benefits, modeling tools are needed to provide rapid evaluation of diverse concepts and to ensure safe operability and peak performance over the mission. The modeling challenge for these vehicles is the ability to show significant benefits over the current highly refined aircraft systems. The STARC-ABL (single-aisle turbo-electric aircraft with an aft boundary layer propulsor) is a new test proposal that builds upon previous N3-X team hybrid designs. This presentation describes the STARC-ABL concept, the NASA Electric Aircraft Testbed (NEAT) which will allow testing of the STARC-ABL powertrain, and the related modeling and simulation efforts to date. Modeling and simulation includes a turbofan simulation, Numeric Propulsion System Simulation (NPSS), which has been integrated with NEAT; and a power systems and control model for predicting testbed performance and evaluating control schemes. Model predictions provide good comparisons with testbed data for an NPSS-integrated test of the single-string configuration of NEAT.

A review on design of experiments and surrogate models in aircraft real-time and many-query aerodynamic analyses

NASA Astrophysics Data System (ADS)

Yondo, Raul; Andrés, Esther; Valero, Eusebio

2018-01-01

Full scale aerodynamic wind tunnel testing, numerical simulation of high dimensional (full-order) aerodynamic models or flight testing are some of the fundamental but complex steps in the various design phases of recent civil transport aircrafts. Current aircraft aerodynamic designs have increase in complexity (multidisciplinary, multi-objective or multi-fidelity) and need to address the challenges posed by the nonlinearity of the objective functions and constraints, uncertainty quantification in aerodynamic problems or the restrained computational budgets. With the aim to reduce the computational burden and generate low-cost but accurate models that mimic those full order models at different values of the design variables, Recent progresses have witnessed the introduction, in real-time and many-query analyses, of surrogate-based approaches as rapid and cheaper to simulate models. In this paper, a comprehensive and state-of-the art survey on common surrogate modeling techniques and surrogate-based optimization methods is given, with an emphasis on models selection and validation, dimensionality reduction, sensitivity analyses, constraints handling or infill and stopping criteria. Benefits, drawbacks and comparative discussions in applying those methods are described. Furthermore, the paper familiarizes the readers with surrogate models that have been successfully applied to the general field of fluid dynamics, but not yet in the aerospace industry. Additionally, the review revisits the most popular sampling strategies used in conducting physical and simulation-based experiments in aircraft aerodynamic design. Attractive or smart designs infrequently used in the field and discussions on advanced sampling methodologies are presented, to give a glance on the various efficient possibilities to a priori sample the parameter space. Closing remarks foster on future perspectives, challenges and shortcomings associated with the use of surrogate models by aircraft industrial

Modeling of aircraft unsteady aerodynamic characteristics. Part 1: Postulated models

NASA Technical Reports Server (NTRS)

Klein, Vladislav; Noderer, Keith D.

1994-01-01

A short theoretical study of aircraft aerodynamic model equations with unsteady effects is presented. The aerodynamic forces and moments are expressed in terms of indicial functions or internal state variables. The first representation leads to aircraft integro-differential equations of motion; the second preserves the state-space form of the model equations. The formulations of unsteady aerodynamics is applied in two examples. The first example deals with a one-degree-of-freedom harmonic motion about one of the aircraft body axes. In the second example, the equations for longitudinal short-period motion are developed. In these examples, only linear aerodynamic terms are considered. The indicial functions are postulated as simple exponentials and the internal state variables are governed by linear, time-invariant, first-order differential equations. It is shown that both approaches to the modeling of unsteady aerodynamics lead to identical models.

Derivation and definition of a linear aircraft model

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Antoniewicz, Robert F.; Krambeer, Keith D.

1988-01-01

A linear aircraft model for a rigid aircraft of constant mass flying over a flat, nonrotating earth is derived and defined. The derivation makes no assumptions of reference trajectory or vehicle symmetry. The linear system equations are derived and evaluated along a general trajectory and include both aircraft dynamics and observation variables.

Reverse engineering of aircraft wing data using a partial differential equation surface model

NASA Astrophysics Data System (ADS)

Huband, Jacalyn Mann

Reverse engineering is a multi-step process used in industry to determine a production representation of an existing physical object. This representation is in the form of mathematical equations that are compatible with computer-aided design and computer-aided manufacturing (CAD/CAM) equipment. The four basic steps to the reverse engineering process are data acquisition, data separation, surface or curve fitting, and CAD/CAM production. The surface fitting step determines the design representation of the object, and thus is critical to the success or failure of the reverse engineering process. Although surface fitting methods described in the literature are used to model a variety of surfaces, they are not suitable for reversing aircraft wings. In this dissertation, we develop and demonstrate a new strategy for reversing a mathematical representation of an aircraft wing. The basis of our strategy is to take an aircraft design model and determine if an inverse model can be derived. A candidate design model for this research is the partial differential equation (PDE) surface model, proposed by Bloor and Wilson and used in the Rapid Airplane Parameter Input Design (RAPID) tool at the NASA-LaRC Geolab. There are several basic mathematical problems involved in reversing the PDE surface model: (i) deriving a computational approximation of the surface function; (ii) determining a radial parametrization of the wing; (iii) choosing mathematical models or classes of functions for representation of the boundary functions; (iv) fitting the boundary data points by the chosen boundary functions; and (v) simultaneously solving for the axial parameterization and the derivative boundary functions. The study of the techniques to solve the above mathematical problems has culminated in a reverse PDE surface model and two reverse PDE surface algorithms. One reverse PDE surface algorithm recovers engineering design parameters for the RAPID tool from aircraft wing data and the other

An economic model for evaluating high-speed aircraft designs

NASA Technical Reports Server (NTRS)

Vandervelden, Alexander J. M.

1989-01-01

A Class 1 method for determining whether further development of a new aircraft design is desirable from all viewpoints is presented. For the manufacturer the model gives an estimate of the total cost of research and development from the preliminary design to the first production aircraft. Using Wright's law of production, one can derive the average cost per aircraft produced for a given break-even number. The model will also provide the airline with a good estimate of the direct and indirect operating costs. From the viewpoint of the passenger, the model proposes a tradeoff between ticket price and cruise speed. Finally all of these viewpoints are combined in a Comparative Aircraft Seat-kilometer Economic Index.

A path model of aircraft noise annoyance

NASA Astrophysics Data System (ADS)

Taylor, S. M.

1984-09-01

This paper describes the development and testing of a path model of aircraft noise annoyance by using noise and social survey data collected in the vicinity of Toronto International Airport. Path analysis is used to estimate the direct and indirect effects of seventeen independent variables on individual annoyance. The results show that the strongest direct effects are for speech interference, attitudes toward aircraft operations, sleep interruption and personal sensitivity to noise. The strongest indirect effects are for aircraft Leq(24) and sensitivity. Overall the model explains 41 percent of the variation in the annoyance reported by the 673 survey respondents. The findings both support and extend existing statements in the literature on the antecedents of annoyance.

Open Vehicle Sketch Pad Aircraft Modeling Strategies

NASA Technical Reports Server (NTRS)

Hahn, Andrew S.

2013-01-01

Geometric modeling of aircraft during the Conceptual design phase is very different from that needed for the Preliminary or Detailed design phases. The Conceptual design phase is characterized by the rapid, multi-disciplinary analysis of many design variables by a small engineering team. The designer must walk a line between fidelity and productivity, picking tools and methods with the appropriate balance of characteristics to achieve the goals of the study, while staying within the available resources. Identifying geometric details that are important, and those that are not, is critical to making modeling and methodology choices. This is true for both the low-order analysis methods traditionally used in Conceptual design as well as the highest-order analyses available. This paper will highlight some of Conceptual design's characteristics that drive the designer s choices as well as modeling examples for several aircraft configurations using the open source version of the Vehicle Sketch Pad (Open VSP) aircraft Conceptual design geometry modeler.

Probabilistic Modeling of Aircraft Trajectories for Dynamic Separation Volumes

NASA Technical Reports Server (NTRS)

Lewis, Timothy A.

2016-01-01

With a proliferation of new and unconventional vehicles and operations expected in the future, the ab initio airspace design will require new approaches to trajectory prediction for separation assurance and other air traffic management functions. This paper presents an approach to probabilistic modeling of the trajectory of an aircraft when its intent is unknown. The approach uses a set of feature functions to constrain a maximum entropy probability distribution based on a set of observed aircraft trajectories. This model can be used to sample new aircraft trajectories to form an ensemble reflecting the variability in an aircraft's intent. The model learning process ensures that the variability in this ensemble reflects the behavior observed in the original data set. Computational examples are presented.

Aircraft Anomaly Detection Using Performance Models Trained on Fleet Data

NASA Technical Reports Server (NTRS)

Gorinevsky, Dimitry; Matthews, Bryan L.; Martin, Rodney

2012-01-01

This paper describes an application of data mining technology called Distributed Fleet Monitoring (DFM) to Flight Operational Quality Assurance (FOQA) data collected from a fleet of commercial aircraft. DFM transforms the data into aircraft performance models, flight-to-flight trends, and individual flight anomalies by fitting a multi-level regression model to the data. The model represents aircraft flight performance and takes into account fixed effects: flight-to-flight and vehicle-to-vehicle variability. The regression parameters include aerodynamic coefficients and other aircraft performance parameters that are usually identified by aircraft manufacturers in flight tests. Using DFM, the multi-terabyte FOQA data set with half-million flights was processed in a few hours. The anomalies found include wrong values of competed variables, (e.g., aircraft weight), sensor failures and baises, failures, biases, and trends in flight actuators. These anomalies were missed by the existing airline monitoring of FOQA data exceedances.

Exposure to fall hazards and safety climate in the aircraft maintenance industry.

PubMed

Neitzel, Richard L; Seixas, Noah S; Harris, Michael J; Camp, Janice

2008-01-01

Falls represent a significant occupational hazard, particularly in industries with dynamic work environments. This paper describes rates of noncompliance with fall hazard prevention requirements, perceived safety climate and worker knowledge and beliefs, and the association between fall exposure and safety climate measures in commercial aircraft maintenance activities. Walkthrough observations were conducted on aircraft mechanics at two participating facilities (Sites A and B) to ascertain the degree of noncompliance. Mechanics at each site completed questionnaires concerning fall hazard knowledge, personal safety beliefs, and safety climate. Questionnaire results were summarized into safety climate and belief scores by workgroup and site. Noncompliance rates observed during walkthroughs were compared to the climate-belief scores, and were expected to be inversely associated. Important differences were seen in fall safety performance between the sites. The study provided a characterization of aircraft maintenance fall hazards, and also demonstrated the effectiveness of an objective hazard assessment methodology. Noncompliance varied by height, equipment used, location of work on the aircraft, shift, and by safety system. Although the expected relationship between safety climate and noncompliance was seen for site-average climate scores, workgroups with higher safety climate scores had greater observed noncompliance within Site A. Overall, use of engineered safety systems had a significant impact on working safely, while safety beliefs and climate also contributed, though inconsistently. The results of this study indicate that safety systems are very important in reducing noncompliance with fall protection requirements in aircraft maintenance facilities. Site-level fall safety compliance was found to be related to safety climate, although an unexpected relationship between compliance and safety climate was seen at the workgroup level within site. Finally, observed

Analysis of technology requirements and potential demand for general aviation avionics systems in the 1980's. [technology assessment and technological forecasting of the aircraft industry

NASA Technical Reports Server (NTRS)

Cohn, D. M.; Kayser, J. H.; Senko, G. M.; Glenn, D. R.

1974-01-01

The trend for the increasing need for aircraft-in-general as a major source of transportation in the United States is presented (military and commercial aircraft are excluded). Social, political, and economic factors that affect the aircraft industry are considered, and cost estimates are given. Aircraft equipment and navigation systems are discussed.

Update of aircraft profile data for the Integrated Noise Model computer program, vol. 3 : appendix B aircraft performance coefficients

DOT National Transportation Integrated Search

1992-03-01

This report provides aircraft takeoff and landing profiles, : aircraft aerodynamic performance coefficients and engine : performance coefficients for the aircraft data base : (Database 9) in the Integrated Noise Model (INM) computer : program. Flight...

Rapid Automated Aircraft Simulation Model Updating from Flight Data

NASA Technical Reports Server (NTRS)

Brian, Geoff; Morelli, Eugene A.

2011-01-01

Techniques to identify aircraft aerodynamic characteristics from flight measurements and compute corrections to an existing simulation model of a research aircraft were investigated. The purpose of the research was to develop a process enabling rapid automated updating of aircraft simulation models using flight data and apply this capability to all flight regimes, including flight envelope extremes. The process presented has the potential to improve the efficiency of envelope expansion flight testing, revision of control system properties, and the development of high-fidelity simulators for pilot training.

An Extensible, Interchangeable and Sharable Database Model for Improving Multidisciplinary Aircraft Design

NASA Technical Reports Server (NTRS)

Lin, Risheng; Afjeh, Abdollah A.

2003-01-01

Crucial to an efficient aircraft simulation-based design is a robust data modeling methodology for both recording the information and providing data transfer readily and reliably. To meet this goal, data modeling issues involved in the aircraft multidisciplinary design are first analyzed in this study. Next, an XML-based. extensible data object model for multidisciplinary aircraft design is constructed and implemented. The implementation of the model through aircraft databinding allows the design applications to access and manipulate any disciplinary data with a lightweight and easy-to-use API. In addition, language independent representation of aircraft disciplinary data in the model fosters interoperability amongst heterogeneous systems thereby facilitating data sharing and exchange between various design tools and systems.

Occupational contact dermatitis caused by aniline epoxy resins in the aircraft industry.

PubMed

Pesonen, Maria; Suuronen, Katri; Jolanki, Riitta; Aalto-Korte, Kristiina; Kuuliala, Outi; Henriks-Eckerman, Maj-Len; Valtanen, Ilona; Alanko, Kristiina

2015-08-01

Tetraglycidyl-4,4'-methylenedianiline (TGMDA) is an aniline epoxy resin used in, for example, resin systems of pre-impregnated composite materials (prepregs) of the aircraft industry. Allergic contact dermatitis caused by TGMDA in prepregs has been described previously. To report on 9 patients with occupational allergic contact dermatitis caused by TGMDA in epoxy glues used in helicopter assembly. The patients were examined with patch testing at the Finnish Institute of Occupational Health in 2004-2009. The first patient was diagnosed by testing both components of two epoxy glues from the workplace, and was also tested with glue ingredients, including TGMDA. The following patients were tested with the glues and TGMDA. The resin parts of the glues were analysed for their epoxy compounds, including TGMDA. All of the patients had a patch test reaction to one or both of the resin parts of the TGMDA-containing glues. Eight of them had a strong allergic reaction to TGMDA, and one had a doubtful reaction to TGMDA. Two of the patients also had an allergic reaction to triglycidyl-p-aminophenol (TGPAP), another aniline epoxy resin, which was not present in the TGMDA-containing glues. In aircraft industry workers with suspected occupational dermatitis, aniline epoxy resins should be considered and patch tested as possible contact allergens. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Propfan test assessment testbed aircraft flutter model test report

NASA Technical Reports Server (NTRS)

Jenness, C. M. J.

1987-01-01

The PropFan Test Assessment (PTA) program includes flight tests of a propfan power plant mounted on the left wind of a modified Gulfstream II testbed aircraft. A static balance boom is mounted on the right wing tip for lateral balance. Flutter analyses indicate that these installations reduce the wing flutter stabilizing speed and that torsional stiffening and the installation of a flutter stabilizing tip boom are required on the left wing for adequate flutter safety margins. Wind tunnel tests of a 1/9th scale high speed flutter model of the testbed aircraft were conducted. The test program included the design, fabrication, and testing of the flutter model and the correlation of the flutter test data with analysis results. Excellent correlations with the test data were achieved in posttest flutter analysis using actual model properties. It was concluded that the flutter analysis method used was capable of accurate flutter predictions for both the (symmetric) twin propfan configuration and the (unsymmetric) single propfan configuration. The flutter analysis also revealed that the differences between the tested model configurations and the current aircraft design caused the (scaled) model flutter speed to be significantly higher than that of the aircraft, at least for the single propfan configuration without a flutter boom. Verification of the aircraft final design should, therefore, be based on flutter predictions made with the test validated analysis methods.

State variable modeling of the integrated engine and aircraft dynamics

NASA Astrophysics Data System (ADS)

Rotaru, Constantin; Sprinţu, Iuliana

2014-12-01

This study explores the dynamic characteristics of the combined aircraft-engine system, based on the general theory of the state variables for linear and nonlinear systems, with details leading first to the separate formulation of the longitudinal and the lateral directional state variable models, followed by the merging of the aircraft and engine models into a single state variable model. The linearized equations were expressed in a matrix form and the engine dynamics was included in terms of variation of thrust following a deflection of the throttle. The linear model of the shaft dynamics for a two-spool jet engine was derived by extending the one-spool model. The results include the discussion of the thrust effect upon the aircraft response when the thrust force associated with the engine has a sizable moment arm with respect to the aircraft center of gravity for creating a compensating moment.

The design of a joined wing flight demonstrator aircraft

NASA Technical Reports Server (NTRS)

Smith, S. C.; Cliff, S. E.; Kroo, I. M.

1987-01-01

A joined-wing flight demonstrator aircraft has been developed at the NASA Ames Research Center in collaboration with ACA Industries. The aircraft is designed to utilize the fuselage, engines, and undercarriage of the existing NASA AD-1 flight demonstrator aircraft. The design objectives, methods, constraints, and the resulting aircraft design, called the JW-1, are presented. A wind-tunnel model of the JW-1 was tested in the NASA Ames 12-foot wind tunnel. The test results indicate that the JW-1 has satisfactory flying qualities for a flight demonstrator aircraft. Good agreement of test results with design predictions confirmed the validity of the design methods used for application to joined-wing configurations.

Apprenticeship as a Model of Vocational "Formation" and "Reformation": The Use of Foundation Degrees in the Aircraft Engineering Industry

ERIC Educational Resources Information Center

Guile, David

2011-01-01

This article argues that once apprenticeship is conceptualised as a social model of learning, then it no longer follows that apprenticeship is an age- or phase-specific model of vocational formation. The article explores this claim through drawing on a case study of the design of a Foundation Degree (FD) in aircraft engineering, which was…

Aircraft Segmentation in SAR Images Based on Improved Active Shape Model

NASA Astrophysics Data System (ADS)

Zhang, X.; Xiong, B.; Kuang, G.

2018-04-01

In SAR image interpretation, aircrafts are the important targets arousing much attention. However, it is far from easy to segment an aircraft from the background completely and precisely in SAR images. Because of the complex structure, different kinds of electromagnetic scattering take place on the aircraft surfaces. As a result, aircraft targets usually appear to be inhomogeneous and disconnected. It is a good idea to extract an aircraft target by the active shape model (ASM), since combination of the geometric information controls variations of the shape during the contour evolution. However, linear dimensionality reduction, used in classic ACM, makes the model rigid. It brings much trouble to segment different types of aircrafts. Aiming at this problem, an improved ACM based on ISOMAP is proposed in this paper. ISOMAP algorithm is used to extract the shape information of the training set and make the model flexible enough to deal with different aircrafts. The experiments based on real SAR data shows that the proposed method achieves obvious improvement in accuracy.

Modeling Aircraft Emissions for Regional-scale Air Quality: Adapting a New Global Aircraft Emissions Database for the U.S

NASA Astrophysics Data System (ADS)

Arunachalam, S.; Baek, B. H.; Vennam, P. L.; Woody, M. C.; Omary, M.; Binkowski, F.; Fleming, G.

2012-12-01

Commercial aircraft emit substantial amounts of pollutants during their complete activity cycle that ranges from landing-and-takeoff (LTO) at airports to cruising in upper elevations of the atmosphere, and affect both air quality and climate. Since these emissions are not uniformly emitted over the earth, and have substantial temporal and spatial variability, it is vital to accurately evaluate and quantify the relative impacts of aviation emissions on ambient air quality. Regional-scale air quality modeling applications do not routinely include these aircraft emissions from all cycles. Federal Aviation Administration (FAA) has developed the Aviation Environmental Design Tool (AEDT), a software system that dynamically models aircraft performance in space and time to calculate fuel burn and emissions from gate-to-gate for all commercial aviation activity from all airports globally. To process in-flight aircraft emissions and to provide a realistic representation of these for treatment in grid-based air quality models, we have developed an interface processor called AEDTproc that accurately distributes full-flight chorded emissions in time and space to create gridded, hourly model-ready emissions input data. Unlike the traditional emissions modeling approach of treating aviation emissions as ground-level sources or processing emissions only from the LTO cycles in regional-scale air quality studies, AEDTproc distributes chorded inventories of aircraft emissions during LTO cycles and cruise activities into a time-variant 3-D gridded structure. We will present results of processed 2006 global emissions from AEDT over a continental U.S. modeling domain to support a national-scale air quality assessment of the incremental impacts of aircraft emissions on surface air quality. This includes about 13.6 million flights within the U.S. out of 31.2 million flights globally. We will focus on assessing spatio-temporal variability of these commercial aircraft emissions, and

Simulation Tools Model Icing for Aircraft Design

NASA Technical Reports Server (NTRS)

2012-01-01

the years from strictly a research tool to one used routinely by industry and other government agencies. Glenn contractor William Wright has been the architect of this development, supported by a team of researchers investigating icing physics, creating validation data, and ensuring development according to standard software engineering practices. The program provides a virtual simulation environment for determining where water droplets strike an airfoil in flight, what kind of ice would result, and what shape that ice would take. Users can enter geometries for specific, two-dimensional cross sections of an airfoil or other airframe surface and then apply a range of inputs - different droplet sizes, temperatures, airspeeds, and more - to model how ice would build up on the surface in various conditions. The program s versatility, ease of use, and speed - LEWICE can run through complex icing simulations in only a few minutes - have contributed to it becoming a popular resource in the aviation industry.

A Small Aircraft Transportation System (SATS) Demand Model

NASA Technical Reports Server (NTRS)

Long, Dou; Lee, David; Johnson, Jesse; Kostiuk, Peter; Yackovetsky, Robert (Technical Monitor)

2001-01-01

The Small Aircraft Transportation System (SATS) demand modeling is a tool that will be useful for decision-makers to analyze SATS demands in both airport and airspace. We constructed a series of models following the general top-down, modular principles in systems engineering. There are three principal models, SATS Airport Demand Model (SATS-ADM), SATS Flight Demand Model (SATS-FDM), and LMINET-SATS. SATS-ADM models SATS operations, by aircraft type, from the forecasts in fleet, configuration and performance, utilization, and traffic mixture. Given the SATS airport operations such as the ones generated by SATS-ADM, SATS-FDM constructs the SATS origin and destination (O&D) traffic flow based on the solution of the gravity model, from which it then generates SATS flights using the Monte Carlo simulation based on the departure time-of-day profile. LMINET-SATS, an extension of LMINET, models SATS demands at airspace and airport by all aircraft operations in US The models use parameters to provide the user with flexibility and ease of use to generate SATS demand for different scenarios. Several case studies are included to illustrate the use of the models, which are useful to identify the need for a new air traffic management system to cope with SATS.

Assessing the shielding of engine noise by the wings for current aircraft using model predictions and measurements.

PubMed

Vieira, Ana; Snellen, Mirjam; Simons, Dick G

2018-01-01

Reducing aircraft noise is a major issue to be dealt with by the aerospace industry. In addition to lowering noise emissions from the engine and airframe, also the shielding of engine noise by the aircraft is considered as a promising means for reducing the perceived noise on the ground. In literature, noise shielding predictions indicate significant reductions in received noise levels for blended wing body configurations, but also for conventional aircraft with the engines placed above the wings. Little work has been done in assessing these potential shielding effects for full aircraft under real operational conditions. Therefore, in this work, noise shielding for current aircraft is investigated using both measurements and model predictions. The predictions are based on the Kirchhoff integral theory and the Modified Theory of Physical Optics. For the comparison between the predictions and measurements, Twenty Fokker 70 flyovers are considered. The data analysis approach for the extraction of shielding levels for aircraft under these operational conditions is presented. Directly under the flight path, the simulations predict an engine noise shielding of 6 dB overall sound pressure level. This is confirmed by some of the flyover data. On average, the measurements show somewhat lower shielding levels.

Comparative Study on the Prediction of Aerodynamic Characteristics of Aircraft with Turbulence Models

NASA Astrophysics Data System (ADS)

Jang, Yujin; Huh, Jinbum; Lee, Namhun; Lee, Seungsoo; Park, Youngmin

2018-04-01

The RANS equations are widely used to analyze complex flows over aircraft. The equations require a turbulence model for turbulent flow analyses. A suitable turbulence must be selected for accurate predictions of aircraft aerodynamic characteristics. In this study, numerical analyses of three-dimensional aircraft are performed to compare the results of various turbulence models for the prediction of aircraft aerodynamic characteristics. A 3-D RANS solver, MSAPv, is used for the aerodynamic analysis. The four turbulence models compared are the Sparlart-Allmaras (SA) model, Coakley's q-ω model, Huang and Coakley's k-ɛ model, and Menter's k-ω SST model. Four aircrafts are considered: an ARA-M100, DLR-F6 wing-body, DLR-F6 wing-body-nacelle-pylon from the second drag prediction workshop, and a high wing aircraft with nacelles. The CFD results are compared with experimental data and other published computational results. The details of separation patterns, shock positions, and Cp distributions are discussed to find the characteristics of the turbulence models.

New methodology for modeling annual-aircraft emissions at airports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woodmansey, B.G.; Patterson, J.G.

An as-accurate-as-possible estimation of total-aircraft emissions are an essential component of any environmental-impact assessment done for proposed expansions at major airports. To determine the amount of emissions generated by aircraft using present models it is necessary to know the emission characteristics of all engines that are on all planes using the airport. However, the published data base does not cover all engine types and, therefore, a new methodology is needed to assist in estimating annual emissions from aircraft at airports. Linear regression equations relating quantity of emissions to aircraft weight using a known-fleet mix are developed in this paper. Total-annualmore » emissions for CO, NO[sub x], NMHC, SO[sub x], CO[sub 2], and N[sub 2]O are tabulated for Toronto's international airport for 1990. The regression equations are statistically significant for all emissions except for NMHC from large jets and NO[sub x] and NMHC for piston-engine aircraft. This regression model is a relatively simple, fast, and inexpensive method of obtaining an annual-emission inventory for an airport.« less

Taxiing, Take-Off, and Landing Simulation of the High Speed Civil Transport Aircraft

NASA Technical Reports Server (NTRS)

Reaves, Mercedes C.; Horta, Lucas G.

1999-01-01

The aircraft industry jointly with NASA is studying enabling technologies for higher speed, longer range aircraft configurations. Higher speeds, higher temperatures, and aerodynamics are driving these newer aircraft configurations towards long, slender, flexible fuselages. Aircraft response during ground operations, although often overlooked, is a concern due to the increased fuselage flexibility. This paper discusses modeling and simulation of the High Speed Civil Transport aircraft during taxiing, take-off, and landing. Finite element models of the airframe for various configurations are used and combined with nonlinear landing gear models to provide a simulation tool to study responses to different ground input conditions. A commercial computer simulation program is used to numerically integrate the equations of motion and to compute estimates of the responses using an existing runway profile. Results show aircraft responses exceeding safe acceptable human response levels.

An aircraft model for the AIAA controls design challenge

NASA Technical Reports Server (NTRS)

Brumbaugh, Randal W.

1991-01-01

A generic, state-of-the-art, high-performance aircraft model, including detailed, full-envelope, nonlinear aerodynamics, and full-envelope thrust and first-order engine response data is described. While this model was primarily developed Controls Design Challenge, the availability of such a model provides a common focus for research in aeronautical control theory and methodology. An implementation of this model using the FORTRAN computer language, associated routines furnished with the aircraft model, and techniques for interfacing these routines to external procedures is also described. Figures showing vehicle geometry, surfaces, and sign conventions are included.

Fuel burn modeling of turboprop aircraft.

DOT National Transportation Integrated Search

2011-08-01

This report documents work done to enhance turbo-propeller aircraft fuel consumption modeling in the Federal Aviation Administrations Aviation Environmental Design Tool (AEDT). Fuel consumption and flight performance data were collected from aircr...

Update of aircraft profile data for the Integrated Noise Model computer program, vol. 2 : appendix A aircraft takeoff and landing profiles

DOT National Transportation Integrated Search

1992-03-01

This report provides aircraft takeoff and landing profiles, aircraft aerodynamic performance coefficients and engine performance coefficients for the aircraft data base (Database 9) in the Integrated Noise Model (INM) computer program. Flight profile...

11. VIEW LOOKING EAST AT MODEL AIRCRAFT CONTROL ROOM; MODEL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

11. VIEW LOOKING EAST AT MODEL AIRCRAFT CONTROL ROOM; MODEL OF BOEING 737 AT TOP OF PHOTOGRAPH IN FULL-SCALE WIND TUNNEL. - NASA Langley Research Center, Full-Scale Wind Tunnel, 224 Hunting Avenue, Hampton, Hampton, VA

Automatic Dynamic Aircraft Modeler (ADAM) for the Computer Program NASTRAN

NASA Technical Reports Server (NTRS)

Griffis, H.

1985-01-01

Large general purpose finite element programs require users to develop large quantities of input data. General purpose pre-processors are used to decrease the effort required to develop structural models. Further reduction of effort can be achieved by specific application pre-processors. Automatic Dynamic Aircraft Modeler (ADAM) is one such application specific pre-processor. General purpose pre-processors use points, lines and surfaces to describe geometric shapes. Specifying that ADAM is used only for aircraft structures allows generic structural sections, wing boxes and bodies, to be pre-defined. Hence with only gross dimensions, thicknesses, material properties and pre-defined boundary conditions a complete model of an aircraft can be created.

A review of unmanned aircraft system ground risk models

NASA Astrophysics Data System (ADS)

Washington, Achim; Clothier, Reece A.; Silva, Jose

2017-11-01

There is much effort being directed towards the development of safety regulations for unmanned aircraft systems (UAS). National airworthiness authorities have advocated the adoption of a risk-based approach, whereby regulations are driven by the outcomes of a systematic process to assess and manage identified safety risks. Subsequently, models characterising the primary hazards associated with UAS operations have now become critical to the development of regulations and in turn, to the future of the industry. Key to the development of airworthiness regulations for UAS is a comprehensive understanding of the risks UAS operations pose to people and property on the ground. A comprehensive review of the literature identified 33 different models (and component sub models) used to estimate ground risk posed by UAS. These models comprise failure, impact location, recovery, stress, exposure, incident stress and harm sub-models. The underlying assumptions and treatment of uncertainties in each of these sub-models differ significantly between models, which can have a significant impact on the development of regulations. This paper reviews the state-of-the-art in research into UAS ground risk modelling, discusses how the various sub-models relate to the different components of the regulation, and explores how model-uncertainties potentially impact the development of regulations for UAS.

A Generic Nonlinear Aerodynamic Model for Aircraft

NASA Technical Reports Server (NTRS)

Grauer, Jared A.; Morelli, Eugene A.

2014-01-01

A generic model of the aerodynamic coefficients was developed using wind tunnel databases for eight different aircraft and multivariate orthogonal functions. For each database and each coefficient, models were determined using polynomials expanded about the state and control variables, and an othgonalization procedure. A predicted squared-error criterion was used to automatically select the model terms. Modeling terms picked in at least half of the analyses, which totalled 45 terms, were retained to form the generic nonlinear aerodynamic (GNA) model. Least squares was then used to estimate the model parameters and associated uncertainty that best fit the GNA model to each database. Nonlinear flight simulations were used to demonstrate that the GNA model produces accurate trim solutions, local behavior (modal frequencies and damping ratios), and global dynamic behavior (91% accurate state histories and 80% accurate aerodynamic coefficient histories) under large-amplitude excitation. This compact aerodynamics model can be used to decrease on-board memory storage requirements, quickly change conceptual aircraft models, provide smooth analytical functions for control and optimization applications, and facilitate real-time parametric system identification.

77 FR 27269 - Access to Aircraft Situation Display to Industry (ASDI) and National Airspace System Status...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-09

... members for this purpose. To assist the FAA in accurately and efficiently processing the number of... information. The receipt of this information could influence whether the FAA can add or delete aircraft from... blocking at the FAA source or at the industry level. The distinction between blocking ASDI data at the FAA...

Modeling and assessment of civil aircraft evacuation based on finer-grid

NASA Astrophysics Data System (ADS)

Fang, Zhi-Ming; Lv, Wei; Jiang, Li-Xue; Xu, Qing-Feng; Song, Wei-Guo

2016-04-01

Studying civil aircraft emergency evacuation process by using computer model is an effective way. In this study, the evacuation of Airbus A380 is simulated using a Finer-Grid Civil Aircraft Evacuation (FGCAE) model. In this model, the effect of seat area and others on escape process and pedestrian's "hesitation" before leaving exits are considered, and an optimized rule of exit choice is defined. Simulations reproduce typical characteristics of aircraft evacuation, such as the movement synchronization between adjacent pedestrians, route choice and so on, and indicate that evacuation efficiency will be determined by pedestrian's "preference" and "hesitation". Based on the model, an assessment procedure of aircraft evacuation safety is presented. The assessment and comparison with the actual evacuation test demonstrate that the available exit setting of "one exit from each exit pair" used by practical demonstration test is not the worst scenario. The half exits of one end of the cabin are all unavailable is the worst one, that should be paid more attention to, and even be adopted in the certification test. The model and method presented in this study could be useful for assessing, validating and improving the evacuation performance of aircraft.

V/STOL tilt rotor aircraft study mathematical model for a real time simulation of a tilt rotor aircraft (Boeing Vertol Model 222), volume 8

NASA Technical Reports Server (NTRS)

Rosenstein, H.; Mcveigh, M. A.; Mollenkof, P. A.

1973-01-01

A mathematical model for a real time simulation of a tilt rotor aircraft was developed. The mathematical model is used for evaluating aircraft performance and handling qualities. The model is based on an eleven degree of freedom total force representation. The rotor is treated as a point source of forces and moments with appropriate response time lags and actuator dynamics. The aerodynamics of the wing, tail, rotors, landing gear, and fuselage are included.

Analysis of aerobatic aircraft noise using the FAA's Integrated Noise Model

DOT National Transportation Integrated Search

2012-09-30

This project has three main objectives. The first objective is to model noise from complete aerobatic routines for a range of aircraft. The second is to compare modeled and previously measured aircraft noise from complete aerobatic routines for a ran...

Video analysis of the flight of a model aircraft

NASA Astrophysics Data System (ADS)

Tarantino, Giovanni; Fazio, Claudio

2011-11-01

A video-analysis software tool has been employed in order to measure the steady-state values of the kinematics variables describing the longitudinal behaviour of a radio-controlled model aircraft during take-off, climbing and gliding. These experimental results have been compared with the theoretical steady-state configurations predicted by the phugoid model for longitudinal flight. A comparison with the parameters and performance of the full-size aircraft has also been outlined.

Integrated Model Reduction and Control of Aircraft with Flexible Wings

NASA Technical Reports Server (NTRS)

Swei, Sean Shan-Min; Zhu, Guoming G.; Nguyen, Nhan T.

2013-01-01

This paper presents an integrated approach to the modeling and control of aircraft with exible wings. The coupled aircraft rigid body dynamics with a high-order elastic wing model can be represented in a nite dimensional state-space form. Given a set of desired output covariance, a model reduction process is performed by using the weighted Modal Cost Analysis (MCA). A dynamic output feedback controller, which is designed based on the reduced-order model, is developed by utilizing output covariance constraint (OCC) algorithm, and the resulting OCC design weighting matrix is used for the next iteration of the weighted cost analysis. This controller is then validated for full-order evaluation model to ensure that the aircraft's handling qualities are met and the uttering motion of the wings suppressed. An iterative algorithm is developed in CONDUIT environment to realize the integration of model reduction and controller design. The proposed integrated approach is applied to NASA Generic Transport Model (GTM) for demonstration.

Modeling and Design Analysis Methodology for Tailoring of Aircraft Structures with Composites

NASA Technical Reports Server (NTRS)

Rehfield, Lawrence W.

2004-01-01

Composite materials provide design flexibility in that fiber placement and orientation can be specified and a variety of material forms and manufacturing processes are available. It is possible, therefore, to 'tailor' the structure to a high degree in order to meet specific design requirements in an optimum manner. Common industrial practices, however, have limited the choices designers make. One of the reasons for this is that there is a dearth of conceptual/preliminary design analysis tools specifically devoted to identifying structural concepts for composite airframe structures. Large scale finite element simulations are not suitable for such purposes. The present project has been devoted to creating modeling and design analysis methodology for use in the tailoring process of aircraft structures. Emphasis has been given to creating bend-twist elastic coupling in high aspect ratio wings or other lifting surfaces. The direction of our work was in concert with the overall NASA effort Twenty- First Century Aircraft Technology (TCAT). A multi-disciplinary team was assembled by Dr. Damodar Ambur to work on wing technology, which included our project.

Very Light Aircraft: Revitalization through Certification

NASA Technical Reports Server (NTRS)

Zyskowski, Michael K.

1995-01-01

As the future of the general aviation industry seems to be improving, a cultural paradigm shift may be imminent with the implementation of an advanced, revolutionary transportation system within the United States. By observing the support of government and industry for this idea, near and long term effects must be addressed if this change is going to occur. The high certification costs associated with general aviation aircraft must be reduced without compromising safety if a new transportation system is to be developed in the future. With the advent of new, streamlined rules recently issued for the certification of small aircraft, it seems as though new opportunities are now available to the general aviation industry. Not only will immediate benefits be realized with increased sales of certified small aircraft, but there would now be a way of introducing the advanced concepts of future aircraft at varying degrees of technology and cost as options to the customer.

The impact of recirculating industrial air on aircraft painting operations.

PubMed

LaPuma, P T; Bolch, W E

1999-10-01

The 1990 Clean Air Act Amendments resulted in new environmental regulations for hazardous air pollutants. Industries such as painting facilities may have to treat large volumes of air, which increases the cost of an air control system. Recirculating a portion of the air back into the facility is an option to reduce the amount of air to be treated. The authors of this study developed a computer model written in Microsoft Excel 97 to analyze the impact of recirculation on worker safety and compliance costs. The model has a chemical database with over 1300 chemicals. The model will predict indoor air concentrations using mass balance calculations and results are compared to occupational exposure limits. A case study is performed on a C-130 aircraft painting facility at Hill Air Force Base, Utah. The model predicts strontium chromate concentrations found in primer paints will reach 1000 times the exposure limit. Strontium chromate and other solid particulates are nearly unaffected by recirculation because the air is filtered during recirculation. The next highest chemical, hexamethylene diisocyanate, increases from 2.6 to 10.5 times the exposure limit at 0 percent and 75 percent recirculation, respectively. Due to the level of respiratory protection required for the strontium chromate, workers are well protected from the modest increases in concentrations caused by recirculating 75 percent of the air. The initial cost of an air control system is $4.5 million with no recirculation and $1.8 million at 75 percent recirculation. The model is an excellent tool to evaluate air control options with a focus on worker safety. In the case study, the model highlights strontium chromate primers as good candidates for substitution. The model shows that recirculating 75 percent of the air at the Hill painting facility has a negligible impact on safety and could save $2.7 million on the initial expenses of a thermal treatment system.

A trade-off analysis design tool. Aircraft interior noise-motion/passenger satisfaction model

NASA Technical Reports Server (NTRS)

Jacobson, I. D.

1977-01-01

A design tool was developed to enhance aircraft passenger satisfaction. The effect of aircraft interior motion and noise on passenger comfort and satisfaction was modelled. Effects of individual aircraft noise sources were accounted for, and the impact of noise on passenger activities and noise levels to safeguard passenger hearing were investigated. The motion noise effect models provide a means for tradeoff analyses between noise and motion variables, and also provide a framework for optimizing noise reduction among noise sources. Data for the models were collected onboard commercial aircraft flights and specially scheduled tests.

Adaptive Failure Compensation for Aircraft Tracking Control Using Engine Differential Based Model

NASA Technical Reports Server (NTRS)

Liu, Yu; Tang, Xidong; Tao, Gang; Joshi, Suresh M.

2006-01-01

An aircraft model that incorporates independently adjustable engine throttles and ailerons is employed to develop an adaptive control scheme in the presence of actuator failures. This model captures the key features of aircraft flight dynamics when in the engine differential mode. Based on this model an adaptive feedback control scheme for asymptotic state tracking is developed and applied to a transport aircraft model in the presence of two types of failures during operation, rudder failure and aileron failure. Simulation results are presented to demonstrate the adaptive failure compensation scheme.

Aircraft Flight Envelope Determination using Upset Detection and Physical Modeling Methods

NASA Technical Reports Server (NTRS)

Keller, Jeffrey D.; McKillip, Robert M. Jr.; Kim, Singwan

2009-01-01

The development of flight control systems to enhance aircraft safety during periods of vehicle impairment or degraded operations has been the focus of extensive work in recent years. Conditions adversely affecting aircraft flight operations and safety may result from a number of causes, including environmental disturbances, degraded flight operations, and aerodynamic upsets. To enhance the effectiveness of adaptive and envelope limiting controls systems, it is desirable to examine methods for identifying the occurrence of anomalous conditions and for assessing the impact of these conditions on the aircraft operational limits. This paper describes initial work performed toward this end, examining the use of fault detection methods applied to the aircraft for aerodynamic performance degradation identification and model-based methods for envelope prediction. Results are presented in which a model-based fault detection filter is applied to the identification of aircraft control surface and stall departure failures/upsets. This application is supported by a distributed loading aerodynamics formulation for the flight dynamics system reference model. Extensions for estimating the flight envelope due to generalized aerodynamic performance degradation are also described.

Flight dynamics simulation modeling and control of a large flexible tiltrotor aircraft

NASA Astrophysics Data System (ADS)

Juhasz, Ondrej

A high order rotorcraft mathematical model is developed and validated against the XV-15 and a Large Civil Tiltrotor (LCTR) concept. The mathematical model is generic and allows for any rotorcraft configuration, from single main rotor helicopters to coaxial and tiltrotor aircraft. Rigid-body and inflow states, as well as flexible wing and blade states are used in the analysis. The separate modeling of each rotorcraft component allows for structural flexibility to be included, which is important when modeling large aircraft where structural modes affect the flight dynamics frequency ranges of interest, generally 1 to 20 rad/sec. Details of the formulation of the mathematical model are given, including derivations of structural, aerodynamic, and inertial loads. The linking of the components of the aircraft is developed using an approach similar to multibody analyses by exploiting a tree topology, but without equations of constraints. Assessments of the effects of wing flexibility are given. Flexibility effects are evaluated by looking at the nature of the couplings between rigid-body modes and wing structural modes and vice versa. The effects of various different forms of structural feedback on aircraft dynamics are analyzed. A proportional-integral feedback on the structural acceleration is deemed to be most effective at both improving the damping and reducing the overall excitation of a structural mode. A model following control architecture is then implemented on full order flexible LCTR models. For this aircraft, the four lowest frequency structural modes are below 20 rad/sec, and are thus needed for control law development and analysis. The impact of structural feedback on both Attitude-Command, Attitude-Hold (ACAH) and Translational Rate Command (TRC) response types are investigated. A rigid aircraft model has optimistic performance characteristics, and a control system designed for a rigid aircraft could potentially destabilize a flexible one. The various

Non-linear aeroelastic prediction for aircraft applications

NASA Astrophysics Data System (ADS)

de C. Henshaw, M. J.; Badcock, K. J.; Vio, G. A.; Allen, C. B.; Chamberlain, J.; Kaynes, I.; Dimitriadis, G.; Cooper, J. E.; Woodgate, M. A.; Rampurawala, A. M.; Jones, D.; Fenwick, C.; Gaitonde, A. L.; Taylor, N. V.; Amor, D. S.; Eccles, T. A.; Denley, C. J.

2007-05-01

Current industrial practice for the prediction and analysis of flutter relies heavily on linear methods and this has led to overly conservative design and envelope restrictions for aircraft. Although the methods have served the industry well, it is clear that for a number of reasons the inclusion of non-linearity in the mathematical and computational aeroelastic prediction tools is highly desirable. The increase in available and affordable computational resources, together with major advances in algorithms, mean that non-linear aeroelastic tools are now viable within the aircraft design and qualification environment. The Partnership for Unsteady Methods in Aerodynamics (PUMA) Defence and Aerospace Research Partnership (DARP) was sponsored in 2002 to conduct research into non-linear aeroelastic prediction methods and an academic, industry, and government consortium collaborated to address the following objectives: To develop useable methodologies to model and predict non-linear aeroelastic behaviour of complete aircraft. To evaluate the methodologies on real aircraft problems. To investigate the effect of non-linearities on aeroelastic behaviour and to determine which have the greatest effect on the flutter qualification process. These aims have been very effectively met during the course of the programme and the research outputs include: New methods available to industry for use in the flutter prediction process, together with the appropriate coaching of industry engineers. Interesting results in both linear and non-linear aeroelastics, with comprehensive comparison of methods and approaches for challenging problems. Additional embryonic techniques that, with further research, will further improve aeroelastics capability. This paper describes the methods that have been developed and how they are deployable within the industrial environment. We present a thorough review of the PUMA aeroelastics programme together with a comprehensive review of the relevant research

Propeller aircraft interior noise model utilization study and validation

NASA Technical Reports Server (NTRS)

Pope, L. D.

1984-01-01

Utilization and validation of a computer program designed for aircraft interior noise prediction is considered. The program, entitled PAIN (an acronym for Propeller Aircraft Interior Noise), permits (in theory) predictions of sound levels inside propeller driven aircraft arising from sidewall transmission. The objective of the work reported was to determine the practicality of making predictions for various airplanes and the extent of the program's capabilities. The ultimate purpose was to discern the quality of predictions for tonal levels inside an aircraft occurring at the propeller blade passage frequency and its harmonics. The effort involved three tasks: (1) program validation through comparisons of predictions with scale-model test results; (2) development of utilization schemes for large (full scale) fuselages; and (3) validation through comparisons of predictions with measurements taken in flight tests on a turboprop aircraft. Findings should enable future users of the program to efficiently undertake and correctly interpret predictions.

Annual Industrial Capabilities Report to Congress

DTIC Science & Technology

2008-03-01

61 5.1 Aircraft Sector Industrial Summary...basis, key contractor workforce capabilities necessary for successful programs. Industry segment-level baseline assessments ( aircraft ; command, control...monitored representative individual corporate divisions for each major industry segment ( aircraft parts and components, water craft, ground vehicles

Aero-Propulsive Model Design from a Commercial Aircraft in Climb and Cruise Regime using Performance Data =

NASA Astrophysics Data System (ADS)

Tudor, Magdalena

IATA has estimated, in 2012, at about 2% of global carbon dioxide emissions, the environmental impact of the air transport, as a consequence caused by the rapidly growing of global movement demand of people and goods, and which was effectively taken into account in the development of the aviation industry. The historic achievements of scientific and technical progress in the field of commercial aviation were contributed to this estimate, and even today the research continues to make progress to help to reduce the emissions of greenhouse gases. Advances in commercial aircraft, and its engine design technology had the aim to improve flight performance. These improvements have enhanced the global flight planning of these types of aircrafts. Almost all of these advances rely on generated performance data as reference sources, the most of which are classified as "confidential" by the aircraft manufacturers. There are very few aero-propulsive models conceived for the climb regime in the literature, but none of them was designed without access to an engine database, and/or to performance data in climb and in cruise regimes with direct applicability for flight optimization. In this thesis, aero-propulsive models methodologies are proposed for climb and cruise regimes, using system identification and validation methods, through which airplane performance can be computed and stored in the most compact and easily accessible format for this kind of performance data. The acquiring of performance data in this format makes it possible to optimize flight profiles, used by on-board Flight Management Systems. The aero-propulsive models developed here were investigated on two aircrafts belonging to commercial class, and both of them had offered very good accuracy. One of their advantages is that they can be adapted to any other aircraft of the same class, even if there is no access to their corresponding engine flight data. In addition, these models could save airlines a considerable

Licencing and Training Reform in the Australian Aircraft Maintenance Industry

ERIC Educational Resources Information Center

Hampson, Ian; Fraser, Doug

2016-01-01

The training and licencing of aircraft maintenance engineers fulfils a crucial protective function since it is they who perform and supervise aircraft maintenance and certify that planes are safe afterwards. In Australia, prior to training reform, a trades-based system of aircraft maintenance engineer training existed in an orderly relation with…

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.

Real-Time Aircraft Cosmic Ray Radiation Exposure Predictions from the NAIRAS Model

NASA Astrophysics Data System (ADS)

Mertens, C. J.; Tobiska, W.; Kress, B. T.; Xu, X.

2012-12-01

The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. There is also interest in extending NAIRAS to the LEO environment to address radiation hazard issues for the emerging commercial spaceflight industry. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. Real-time observations are required at a variety of locations within the geospace environment. The NAIRAS model is driven by real-time input data from ground-, atmospheric-, and space-based platforms. During the development of the NAIRAS model, new science questions and observational data gaps were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. The focus of this talk is to present the current capabilities of the NAIRAS model, discuss future developments in aviation radiation modeling and instrumentation, and propose strategies and methodologies of bridging known gaps in current modeling and observational capabilities.

Aircraft production technology

NASA Astrophysics Data System (ADS)

Horne, Douglas Favel

Current aircraft-production techniques are surveyed and illustrated with extensive drawings, diagrams, and photographs. The history of the British aircraft industry is reviewed, and individual chapters are devoted to Al alloys; steels, Ni alloys, and Ti alloys; metal-cutting machinery; welding and brazing; surface treatments; protective treatments; sheet-metal working; nonmetallic materials; assembly; inspection and testing; and production estimates, production planning, and CAD/CAM.

Aircraft Flight Modeling During the Optimization of Gas Turbine Engine Working Process

NASA Astrophysics Data System (ADS)

Tkachenko, A. Yu; Kuz'michev, V. S.; Krupenich, I. N.

2018-01-01

The article describes a method for simulating the flight of the aircraft along a predetermined path, establishing a functional connection between the parameters of the working process of gas turbine engine and the efficiency criteria of the aircraft. This connection is necessary for solving the optimization tasks of the conceptual design stage of the engine according to the systems approach. Engine thrust level, in turn, influences the operation of aircraft, thus making accurate simulation of the aircraft behavior during flight necessary for obtaining the correct solution. The described mathematical model of aircraft flight provides the functional connection between the airframe characteristics, working process of gas turbine engines (propulsion system), ambient and flight conditions and flight profile features. This model provides accurate results of flight simulation and the resulting aircraft efficiency criteria, required for optimization of working process and control function of a gas turbine engine.

Annual Industrial Capabilities Report to Congress

DTIC Science & Technology

2007-02-01

65 5.1 Aircraft Sector Industrial Summary ................................................................. 65 5.2 Command...industry partners to encourage long-term contractor workforce improvements. Industry segment-level baseline assessments ( aircraft ; command, control...For instance, within aircraft major defense acquisition programs (MDAPs), research, development, test, and evaluation (RDT&E) funding is steadily

Propeller aircraft interior noise model

NASA Technical Reports Server (NTRS)

Pope, L. D.; Wilby, E. G.; Wilby, J. F.

1984-01-01

An analytical model was developed to predict the interior noise of propeller-driven aircraft. The fuselage model is that of a cylinder with a structurally-integral floor. The cabin sidewall is stiffened by stringers and ring frames, and the floor by longitudinal beams. The cabin interior is covered with a sidewall treatments consisting of layers of porous material and an impervious trim septum. Representation of the propeller pressure field is utilized as input data in the form of the propeller noise signature at a series of locations on a grid over the fuselage structure. Results obtained from the analytical model are compared with test data measured by NASA in a scale model cylindrical fuselage excited by a model propeller.

Mathematical model for lift/cruise fan V/STOL aircraft simulator programming data

NASA Technical Reports Server (NTRS)

Bland, M. P.; Fajfar, B.; Konsewicz, R. K.

1976-01-01

Simulation data are reported for the purpose of programming the flight simulator for advanced aircraft for tests of the lift/cruise fan V/STOL Research Technology Aircraft. These simulation tests are to provide insight into problem areas which are encountered in operational use of the aircraft. A mathematical model is defined in sufficient detail to represent all the necessary pertinent aircraft and system characteristics. The model includes the capability to simulate two basic versions of an aircraft propulsion system: (1) the gas coupled configuration which uses insulated air ducts to transmit power between gas generators and fans in the form of high energy engine exhaust and (2) the mechanically coupled power system which uses shafts, clutches, and gearboxes for power transmittal. Both configurations are modeled such that the simulation can include vertical as well as rolling takeoff and landing, hover, powered lift flight, aerodynamic flight, and the transition between powered lift and aerodynamic flight.

Longitudinal control of aircraft dynamics based on optimization of PID parameters

NASA Astrophysics Data System (ADS)

Deepa, S. N.; Sudha, G.

2016-03-01

Recent years many flight control systems and industries are employing PID controllers to improve the dynamic behavior of the characteristics. In this paper, PID controller is developed to improve the stability and performance of general aviation aircraft system. Designing the optimum PID controller parameters for a pitch control aircraft is important in expanding the flight safety envelope. Mathematical model is developed to describe the longitudinal pitch control of an aircraft. The PID controller is designed based on the dynamic modeling of an aircraft system. Different tuning methods namely Zeigler-Nichols method (ZN), Modified Zeigler-Nichols method, Tyreus-Luyben tuning, Astrom-Hagglund tuning methods are employed. The time domain specifications of different tuning methods are compared to obtain the optimum parameters value. The results prove that PID controller tuned by Zeigler-Nichols for aircraft pitch control dynamics is better in stability and performance in all conditions. Future research work of obtaining optimum PID controller parameters using artificial intelligence techniques should be carried out.

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.

Model Assessment of the Impact on Ozone of Subsonic and Supersonic Aircraft

NASA Technical Reports Server (NTRS)

Ko, Malcolm; Weisenstein, Debra; Danilin, Michael; Scott, Courtney; Shia, Run-Lie

2000-01-01

This is the final report for work performed between June 1999 through May 2000. The work represents continuation of the previous contract which encompasses five areas: (1) continued refinements and applications of the 2-D chemistry-transport model (CTM) to assess the ozone effects from aircraft operation in the stratosphere; (2) studying the mechanisms that determine the evolution of the sulfur species in the aircraft plume and how such mechanisms affect the way aircraft sulfur emissions should be introduced into global models; (3) the development of diagnostics in the AER 3-wave interactive model to assess the importance of the dynamics feedback and zonal asymmetry in model prediction of ozone response to aircraft operation; (4) the development of a chemistry parameterization scheme in support of the global modeling initiative (GMI); and (5) providing assessment results for preparation of national and international reports which include the "Aviation and the Global Atmosphere" prepared by the Intergovernmental Panel on Climate Change, "Assessment of the effects of high-speed aircraft in the stratosphere: 1998" by NASA, and the "Model and Measurements Intercomparison II" by NASA. Part of the work was reported in the final report. We participated in the SAGE III Ozone Loss and Validation Experiment (SOLVE) campaign and we continue with our analyses of the data.

Biohydrogen production from industrial wastewaters.

PubMed

Moreno-Andrade, Iván; Moreno, Gloria; Kumar, Gopalakrishnan; Buitrón, Germán

2015-01-01

The feasibility of producing hydrogen from various industrial wastes, such as vinasses (sugar and tequila industries), and raw and physicochemical-treated wastewater from the plastic industry and toilet aircraft wastewater, was evaluated. The results showed that the tequila vinasses presented the maximum hydrogen generation potential, followed by the raw plastic industry wastewater, aircraft wastewater, and physicochemical-treated wastewater from the plastic industry and sugar vinasses, respectively. The hydrogen production from the aircraft wastewater was increased by the adaptation of the microorganisms in the anaerobic sequencing batch reactor.

Static Aeroelastic and Longitudinal Trim Model of Flexible Wing Aircraft Using Finite-Element Vortex-Lattice Coupled Solution

NASA Technical Reports Server (NTRS)

Ting, Eric; Nguyen, Nhan; Trinh, Khanh

2014-01-01

This paper presents a static aeroelastic model and longitudinal trim model for the analysis of a flexible wing transport aircraft. The static aeroelastic model is built using a structural model based on finite-element modeling and coupled to an aerodynamic model that uses vortex-lattice solution. An automatic geometry generation tool is used to close the loop between the structural and aerodynamic models. The aeroelastic model is extended for the development of a three degree-of-freedom longitudinal trim model for an aircraft with flexible wings. The resulting flexible aircraft longitudinal trim model is used to simultaneously compute the static aeroelastic shape for the aircraft model and the longitudinal state inputs to maintain an aircraft trim state. The framework is applied to an aircraft model based on the NASA Generic Transport Model (GTM) with wing structures allowed to flexibly deformed referred to as the Elastically Shaped Aircraft Concept (ESAC). The ESAC wing mass and stiffness properties are based on a baseline "stiff" values representative of current generation transport aircraft.

The Simulation of a Jumbo Jet Transport Aircraft. Volume 2: Modeling Data

NASA Technical Reports Server (NTRS)

Hanke, C. R.; Nordwall, D. R.

1970-01-01

The manned simulation of a large transport aircraft is described. Aircraft and systems data necessary to implement the mathematical model described in Volume I and a discussion of how these data are used in model are presented. The results of the real-time computations in the NASA Ames Research Center Flight Simulator for Advanced Aircraft are shown and compared to flight test data and to the results obtained in a training simulator known to be satisfactory.

Rapid Prototyping of an Aircraft Model in an Object-Oriented Simulation

NASA Technical Reports Server (NTRS)

Kenney, P. Sean

2003-01-01

A team was created to participate in the Mars Scout Opportunity. Trade studies determined that an aircraft provided the best opportunity to complete the science objectives of the team. A high fidelity six degree of freedom flight simulation was required to provide credible evidence that the aircraft design fulfilled mission objectives and to support the aircraft design process by providing performance evaluations. The team created the simulation using the Langley Standard Real-Time Simulation in C++ (LaSRS++) application framework. A rapid prototyping approach was necessary because the team had only three months to both develop the aircraft simulation model and evaluate aircraft performance as the design and mission parameters matured. The design of LaSRS++ enabled rapid-prototyping in several ways. First, the framework allowed component models to be designed, implemented, unit-tested, and integrated quickly. Next, the framework provides a highly reusable infrastructure that allowed developers to maximize code reuse while concentrating on aircraft and mission specific features. Finally, the framework reduces risk by providing reusable components that allow developers to build a quality product with a compressed testing cycle that relies heavily on unit testing of new components.

Models and techniques for evaluating the effectiveness of aircraft computing systems

NASA Technical Reports Server (NTRS)

Meyer, J. F.

1982-01-01

Models, measures, and techniques for evaluating the effectiveness of aircraft computing systems were developed. By "effectiveness" in this context we mean the extent to which the user, i.e., a commercial air carrier, may expect to benefit from the computational tasks accomplished by a computing system in the environment of an advanced commercial aircraft. Thus, the concept of effectiveness involves aspects of system performance, reliability, and worth (value, benefit) which are appropriately integrated in the process of evaluating system effectiveness. Specifically, the primary objectives are: the development of system models that provide a basis for the formulation and evaluation of aircraft computer system effectiveness, the formulation of quantitative measures of system effectiveness, and the development of analytic and simulation techniques for evaluating the effectiveness of a proposed or existing aircraft computer.

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.

NASA's aircraft icing technology program

NASA Technical Reports Server (NTRS)

Reinmann, John J.

1991-01-01

NASA' Aircraft Icing Technology program is aimed at developing innovative technologies for safe and efficient flight into forecasted icing. The program addresses the needs of all aircraft classes and supports both commercial and military applications. The program is guided by three key strategic objectives: (1) numerically simulate an aircraft's response to an in-flight icing encounter, (2) provide improved experimental icing simulation facilities and testing techniques, and (3) offer innovative approaches to ice protection. Our research focuses on topics that directly support stated industry needs, and we work closely with industry to assure a rapid and smooth transfer of technology. This paper presents selected results that illustrate progress towards the three strategic objectives, and it provides a comprehensive list of references on the NASA icing program.

Improving the Aircraft Design Process Using Web-Based Modeling and Simulation

NASA Technical Reports Server (NTRS)

Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.; Follen, Gregory J. (Technical Monitor)

2000-01-01

Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and multifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

Improving the Aircraft Design Process Using Web-based Modeling and Simulation

NASA Technical Reports Server (NTRS)

Reed, John A.; Follen, Gregory J.; Afjeh, Abdollah A.

2003-01-01

Designing and developing new aircraft systems is time-consuming and expensive. Computational simulation is a promising means for reducing design cycle times, but requires a flexible software environment capable of integrating advanced multidisciplinary and muitifidelity analysis methods, dynamically managing data across heterogeneous computing platforms, and distributing computationally complex tasks. Web-based simulation, with its emphasis on collaborative composition of simulation models, distributed heterogeneous execution, and dynamic multimedia documentation, has the potential to meet these requirements. This paper outlines the current aircraft design process, highlighting its problems and complexities, and presents our vision of an aircraft design process using Web-based modeling and simulation.

A performance improvement case study in aircraft maintenance and its implications for hazard identification.

PubMed

Ward, Marie; McDonald, Nick; Morrison, Rabea; Gaynor, Des; Nugent, Tony

2010-02-01

Aircraft maintenance is a highly regulated, safety critical, complex and competitive industry. There is a need to develop innovative solutions to address process efficiency without compromising safety and quality. This paper presents the case that in order to improve a highly complex system such as aircraft maintenance, it is necessary to develop a comprehensive and ecologically valid model of the operational system, which represents not just what is meant to happen, but what normally happens. This model then provides the backdrop against which to change or improve the system. A performance report, the Blocker Report, specific to aircraft maintenance and related to the model was developed gathering data on anything that 'blocks' task or check performance. A Blocker Resolution Process was designed to resolve blockers and improve the current check system. Significant results were obtained for the company in the first trial and implications for safety management systems and hazard identification are discussed. Statement of Relevance: Aircraft maintenance is a safety critical, complex, competitive industry with a need to develop innovative solutions to address process and safety efficiency. This research addresses this through the development of a comprehensive and ecologically valid model of the system linked with a performance reporting and resolution system.

World commercial aircraft accidents

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, C.Y.

1993-01-01

This report is a compilation of all accidents world-wide involving aircraft in commercial service which resulted in the loss of the airframe or one or more fatality, or both. This information has been gathered in order to present a complete inventory of commercial aircraft accidents. Events involving military action, sabotage, terrorist bombings, hijackings, suicides, and industrial ground accidents are included within this list. Included are: accidents involving world commercial jet aircraft, world commercial turboprop aircraft, world commercial pistonprop aircraft with four or more engines and world commercial pistonprop aircraft with two or three engines from 1946 to 1992. Each accidentmore » is presented with information in the following categories: date of the accident, airline and its flight numbers, type of flight, type of aircraft, aircraft registration number, construction number/manufacturers serial number, aircraft damage, accident flight phase, accident location, number of fatalities, number of occupants, cause, remarks, or description (brief) of the accident, and finally references used. The sixth chapter presents a summary of the world commercial aircraft accidents by major aircraft class (e.g. jet, turboprop, and pistonprop) and by flight phase. The seventh chapter presents several special studies including a list of world commercial aircraft accidents for all aircraft types with 100 or more fatalities in order of decreasing number of fatalities, a list of collision accidents involving commercial aircrafts, and a list of world commercial aircraft accidents for all aircraft types involving military action, sabotage, terrorist bombings, and hijackings.« less

Modeling Aircraft Wing Loads from Flight Data Using Neural Networks

NASA Technical Reports Server (NTRS)

Allen, Michael J.; Dibley, Ryan P.

2003-01-01

Neural networks were used to model wing bending-moment loads, torsion loads, and control surface hinge-moments of the Active Aeroelastic Wing (AAW) aircraft. Accurate loads models are required for the development of control laws designed to increase roll performance through wing twist while not exceeding load limits. Inputs to the model include aircraft rates, accelerations, and control surface positions. Neural networks were chosen to model aircraft loads because they can account for uncharacterized nonlinear effects while retaining the capability to generalize. The accuracy of the neural network models was improved by first developing linear loads models to use as starting points for network training. Neural networks were then trained with flight data for rolls, loaded reversals, wind-up-turns, and individual control surface doublets for load excitation. Generalization was improved by using gain weighting and early stopping. Results are presented for neural network loads models of four wing loads and four control surface hinge moments at Mach 0.90 and an altitude of 15,000 ft. An average model prediction error reduction of 18.6 percent was calculated for the neural network models when compared to the linear models. This paper documents the input data conditioning, input parameter selection, structure, training, and validation of the neural network models.

Identification of aerodynamic models for maneuvering aircraft

NASA Technical Reports Server (NTRS)

Chin, Suei; Lan, C. Edward

1990-01-01

Due to the requirement of increased performance and maneuverability, the flight envelope of a modern fighter is frequently extended to the high angle-of-attack regime. Vehicles maneuvering in this regime are subjected to nonlinear aerodynamic loads. The nonlinearities are due mainly to three-dimensional separated flow and concentrated vortex flow that occur at large angles of attack. Accurate prediction of these nonlinear airloads is of great importance in the analysis of a vehicle's flight motion and in the design of its flight control system. A satisfactory evaluation of the performance envelope of the aircraft may require a large number of coupled computations, one for each change in initial conditions. To avoid the disadvantage of solving the coupled flow-field equations and aircraft's motion equations, an alternate approach is to use a mathematical modeling to describe the steady and unsteady aerodynamics for the aircraft equations of motion. Aerodynamic forces and moments acting on a rapidly maneuvering aircraft are, in general, nonlinear functions of motion variables, their time rate of change, and the history of maneuvering. A numerical method was developed to analyze the nonlinear and time-dependent aerodynamic response to establish the generalized indicial function in terms of motion variables and their time rates of change.

Rotor systems research aircraft simulation mathematical model

NASA Technical Reports Server (NTRS)

Houck, J. A.; Moore, F. L.; Howlett, J. J.; Pollock, K. S.; Browne, M. M.

1977-01-01

An analytical model developed for evaluating and verifying advanced rotor concepts is discussed. The model was used during in both open loop and real time man-in-the-loop simulation during the rotor systems research aircraft design. Future applications include: pilot training, preflight of test programs, and the evaluation of promising concepts before their implementation on the flight vehicle.

Models and techniques for evaluating the effectiveness of aircraft computing systems

NASA Technical Reports Server (NTRS)

Meyer, J. F.

1978-01-01

The development of system models that can provide a basis for the formulation and evaluation of aircraft computer system effectiveness, the formulation of quantitative measures of system effectiveness, and the development of analytic and simulation techniques for evaluating the effectiveness of a proposed or existing aircraft computer are described. Specific topics covered include: system models; performability evaluation; capability and functional dependence; computation of trajectory set probabilities; and hierarchical modeling of an air transport mission.

Aerodynamics Model for a Generic ASTOVL Lift-Fan Aircraft

DOT National Transportation Integrated Search

1995-04-01

This report describes the aerodynamics model used in a simulation model of : an advanced short takeoff and vertical landing lift-far fighter aircraft. The : simulation model was developed for use in piloted evaluations of transition and : hover fligh...

75 FR 12665 - Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76C Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-17

... Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76C Helicopters AGENCY: Federal Aviation... directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) Model S-76C helicopters. This... installed in the left-hand flotation system connector of a Model S-76C helicopter. The actions specified in...

Development of Nonlinear Flight Mechanical Model of High Aspect Ratio Light Utility Aircraft

NASA Astrophysics Data System (ADS)

Bahri, S.; Sasongko, R. A.

2018-04-01

The implementation of Flight Control Law (FCL) for Aircraft Electronic Flight Control System (EFCS) aims to reduce pilot workload, while can also enhance the control performance during missions that require long endurance flight and high accuracy maneuver. In the development of FCL, a quantitative representation of the aircraft dynamics is needed for describing the aircraft dynamics characteristic and for becoming the basis of the FCL design. Hence, a 6 Degree of Freedom nonlinear model of a light utility aircraft dynamics, also called the nonlinear Flight Mechanical Model (FMM), is constructed. This paper shows the construction of FMM from mathematical formulation, the architecture design of FMM, the trimming process and simulations. The verification of FMM is done by analysis of aircraft behaviour in selected trimmed conditions.

Combustion system CFD modeling at GE Aircraft Engines

NASA Technical Reports Server (NTRS)

Burrus, D.; Mongia, H.; Tolpadi, Anil K.; Correa, S.; Braaten, M.

1995-01-01

This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.

Combustion system CFD modeling at GE Aircraft Engines

NASA Astrophysics Data System (ADS)

Burrus, D.; Mongia, H.; Tolpadi, Anil K.; Correa, S.; Braaten, M.

1995-03-01

This viewgraph presentation discusses key features of current combustion system CFD modeling capabilities at GE Aircraft Engines provided by the CONCERT code; CONCERT development history; modeling applied for designing engine combustion systems; modeling applied to improve fundamental understanding; CONCERT3D results for current production combustors; CONCERT3D model of NASA/GE E3 combustor; HYBRID CONCERT CFD/Monte-Carlo modeling approach; and future modeling directions.

Modelling and extraction technique for micro-doppler signature of aircraft rotor blades

NASA Astrophysics Data System (ADS)

Praveen, N.; Valarmathi, J.

2017-11-01

The process of detecting and distinguishing between different aircrafts has been a major point of interest in Defence applications. Micro-Doppler effect is one such phenomenon unique for aircrafts with different rotor dynamics and design. In this paper, we focus on deducing a mathematical model for micro-Doppler signature, of aircraft rotor blades assumed to be rotating in a plane perpendicular to the flying direction, induced on the incident radar signal. Also, we use the Wigner-Ville Distribution (WVD) to extract this signature from the radar return. This mathematical model is compared with the simulation results obtained from MATLAB, to validate the results and show the accurateness of the developed model.

LINEAR - DERIVATION AND DEFINITION OF A LINEAR AIRCRAFT MODEL

NASA Technical Reports Server (NTRS)

Duke, E. L.

1994-01-01

The Derivation and Definition of a Linear Model program, LINEAR, provides the user with a powerful and flexible tool for the linearization of aircraft aerodynamic models. LINEAR was developed to provide a standard, documented, and verified tool to derive linear models for aircraft stability analysis and control law design. Linear system models define the aircraft system in the neighborhood of an analysis point and are determined by the linearization of the nonlinear equations defining vehicle dynamics and sensors. LINEAR numerically determines a linear system model using nonlinear equations of motion and a user supplied linear or nonlinear aerodynamic model. The nonlinear equations of motion used are six-degree-of-freedom equations with stationary atmosphere and flat, nonrotating earth assumptions. LINEAR is capable of extracting both linearized engine effects, such as net thrust, torque, and gyroscopic effects and including these effects in the linear system model. The point at which this linear model is defined is determined either by completely specifying the state and control variables, or by specifying an analysis point on a trajectory and directing the program to determine the control variables and the remaining state variables. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to provide easy selection of state, control, and observation variables to be used in a particular model. Thus, the order of the system model is completely under user control. Further, the program provides the flexibility of allowing alternate formulations of both the state and observation equations. Data describing the aircraft and the test case is input to the program through a terminal or formatted data files. All data can be modified interactively from case to case. The aerodynamic model can be defined in two ways: a set of nondimensional stability and control derivatives for the flight point of

76 FR 27239 - Airworthiness Directives; Cessna Aircraft Company (Cessna) Model 172 Airplanes Modified by...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-11

... Airworthiness Directives; Cessna Aircraft Company (Cessna) Model 172 Airplanes Modified by Supplemental Type... months for Cessna Aircraft Company (Cessna) Model 172 Airplanes modified by Supplemental Type Certificate...

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.

Aircraft Electric/Hybrid-Electric Power and Propulsion Workshop Perspective of the V/STOL Aircraft Systems Tech Committee

NASA Technical Reports Server (NTRS)

Hange, Craig E.

2016-01-01

This presentation will be given at the AIAA Electric Hybrid-Electric Power Propulsion Workshop on July 29, 2016. The workshop is being held so the AIAA can determine how it can support the introduction of electric aircraft into the aerospace industry. This presentation will address the needs of the community within the industry that advocates the use of powered-lift as important new technologies for future aircraft and air transportation systems. As the current chairman of the VSTOL Aircraft Systems Technical Committee, I will be presenting generalized descriptions of the past research in developing powered-lift and generalized observations on how electric and hybrid-electric propulsion may provide advances in the powered-lift field.

Flight dynamics and control modelling of damaged asymmetric aircraft

NASA Astrophysics Data System (ADS)

Ogunwa, T. T.; Abdullah, E. J.

2016-10-01

This research investigates the use of a Linear Quadratic Regulator (LQR) controller to assist commercial Boeing 747-200 aircraft regains its stability in the event of damage. Damages cause an aircraft to become asymmetric and in the case of damage to a fraction (33%) of its left wing or complete loss of its vertical stabilizer, the loss of stability may lead to a fatal crash. In this study, aircraft models for the two damage scenarios previously mentioned are constructed using stability derivatives. LQR controller is used as a direct adaptive control design technique for the observable and controllable system. Dynamic stability analysis is conducted in the time domain for all systems in this study.

Aerodynamics model for a generic ASTOVL lift-fan aircraft

NASA Technical Reports Server (NTRS)

Birckelbaw, Lourdes G.; Mcneil, Walter E.; Wardwell, Douglas A.

1995-01-01

This report describes the aerodynamics model used in a simulation model of an advanced short takeoff and vertical landing (ASTOVL) lift-fan fighter aircraft. The simulation model was developed for use in piloted evaluations of transition and hover flight regimes, so that only low speed (M approximately 0.2) aerodynamics are included in the mathematical model. The aerodynamic model includes the power-off aerodynamic forces and moments and the propulsion system induced aerodynamic effects, including ground effects. The power-off aerodynamics data were generated using the U.S. Air Force Stability and Control Digital DATCOM program and a NASA Ames in-house graphics program called VORVIEW which allows the user to easily analyze arbitrary conceptual aircraft configurations using the VORLAX program. The jet-induced data were generated using the prediction methods of R. E. Kuhn et al., as referenced in this report.

Musculoskeletal disorders and psychosocial risk factors among workers of the aircraft maintenance industry.

PubMed

Nogueira, Helen Cristina; Diniz, Ana Carolina Parise; Barbieri, Dechristian França; Padula, Rosimeire Simprini; Carregaro, Rodrigo Luiz; de Oliveira, Ana Beatriz

2012-01-01

During the recent decades Brazil has experienced an exponential growth in the aviation sector resulting in an increasing workforce. The aircraft maintenance industry stands out, where the workers have to handle different kind of objects. The aim of this study was to evaluate psychosocial indicators as well as musculoskeletal symptoms and disorders among aircraft maintenance workers. One hundred and one employees were evaluated (32.69 ± 8.25 yr, 79.8 ± 13.4 kg, and 1.75 ± 0.07 m). Musculoskeletal symptoms and disorders were assessed through the Nordic Musculoskeletal Questionnaire (NMQ) and a standardized physical examination. The Job Content Questionnaire (JCQ) and the Utrecht Work Engagement Scale (UWES) were applied to evaluate psychosocial indicators. Results of the NMQ indicate the lower back as the most affected body region. On the other hand, the physical examination has shown clinical diagnosis of shoulder disorders. Neck, upper back and ankle/foot were also reported as painful sites. Most of workers have active work-demand profile and high work engagement levels. We suggest that musculoskeletal symptoms may be related to high biomechanical demand of the tasks performed by workers, what must be further investigated.

Dynamic Model of Aircraft Passenger Seats for Vibration Comfort Evaluation and Control

NASA Astrophysics Data System (ADS)

Šika, Z.; Valášek, Michael; Vampola, T.; Füllekrug, U.; Klimmek, T.

The paper deals with the development of the seat dynamical model for vibration comfort evaluation and control. The aircraft seats have been tested extensively by vibrations on the 6 DOF vibrating platform. The importance of the careful comfort control together with the flight mechanics control is namely stressed for the blended wing body (BWB) aircrafts. They have a very large fuselage, where the mechanical properties (accelerations, angular accelerations) vary considerably for different seat places. The model have been improved by adding of dynamical models of the aircraft passenger seats identified by the measurements on the 6 DOF vibrating platform. The experiments, their results and the identification of the dynamical seat model are described. The model is further modified by adding of the comfort evaluation norms represented by dynamical filters. The structure and identification of the seat model is briefly described and discussed.

Progress in Space Weather Modeling and Observations Needed to Improve the Operational NAIRAS Model Aircraft Radiation Exposure Predictions

NASA Astrophysics Data System (ADS)

Mertens, C. J.; Kress, B. T.; Wiltberger, M. J.; Tobiska, W.; Xu, X.

2011-12-01

The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a prototype operational model for predicting commercial aircraft radiation exposure from galactic and solar cosmic rays. NAIRAS predictions are currently streaming live from the project's public website, and the exposure rate nowcast is also available on the SpaceWx smartphone app for iPhone, IPad, and Android. Cosmic rays are the primary source of human exposure to high linear energy transfer radiation at aircraft altitudes, which increases the risk of cancer and other adverse health effects. Thus, the NAIRAS model addresses an important national need with broad societal, public health and economic benefits. The processes responsible for the variability in the solar wind, interplanetary magnetic field, solar energetic particle spectrum, and the dynamical response of the magnetosphere to these space environment inputs, strongly influence the composition and energy distribution of the atmospheric ionizing radiation field. During the development of the NAIRAS model, new science questions were identified that must be addressed in order to obtain a more reliable and robust operational model of atmospheric radiation exposure. Addressing these science questions require improvements in both space weather modeling and observations. The focus of this talk is to present these science questions, the proposed methodologies for addressing these science questions, and the anticipated improvements to the operational predictions of atmospheric radiation exposure. The overarching goal of this work is to provide a decision support tool for the aviation industry that will enable an optimal balance to be achieved between minimizing health risks to passengers and aircrew while simultaneously minimizing costs to the airline companies.

Propeller aircraft interior noise model. II - Scale-model and flight-test comparisons

NASA Technical Reports Server (NTRS)

Willis, C. M.; Mayes, W. H.

1987-01-01

A program for predicting the sound levels inside propeller driven aircraft arising from sidewall transmission of airborne exterior noise is validated through comparisons of predictions with both scale-model test results and measurements obtained in flight tests on a turboprop aircraft. The program produced unbiased predictions for the case of the scale-model tests, with a standard deviation of errors of about 4 dB. For the case of the flight tests, the predictions revealed a bias of 2.62-4.28 dB (depending upon whether or not the data for the fourth harmonic were included) and the standard deviation of the errors ranged between 2.43 and 4.12 dB. The analytical model is shown to be capable of taking changes in the flight environment into account.

A Novel Modeling Method for Aircraft Engine Using Nonlinear Autoregressive Exogenous (NARX) Models Based on Wavelet Neural Networks

NASA Astrophysics Data System (ADS)

Yu, Bing; Shu, Wenjun; Cao, Can

2018-05-01

A novel modeling method for aircraft engine using nonlinear autoregressive exogenous (NARX) models based on wavelet neural networks is proposed. The identification principle and process based on wavelet neural networks are studied, and the modeling scheme based on NARX is proposed. Then, the time series data sets from three types of aircraft engines are utilized to build the corresponding NARX models, and these NARX models are validated by the simulation. The results show that all the best NARX models can capture the original aircraft engine's dynamic characteristic well with the high accuracy. For every type of engine, the relative identification errors of its best NARX model and the component level model are no more than 3.5 % and most of them are within 1 %.

76 FR 14346 - Airworthiness Directives; Diamond Aircraft Industries GmbH Model DA 42 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-16

... Industries GmbH Model DA 42 Airplanes AGENCY: Federal Aviation Administration (FAA), Department of... been reportedly found on DA 42 Main Landing Gear (MLG) Damper-to-Trailing Arm joints during standard... condition for the specified products. The MCAI states: Cracks have been reportedly found on DA 42 Main...

Aircraft/Air Traffic Management Functional Analysis Model: Technical Description. 2.0

NASA Technical Reports Server (NTRS)

Etheridge, Melvin; Plugge, Joana; Retina, Nusrat

1998-01-01

The Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 (FAM 2.0), is a discrete event simulation model designed to support analysis of alternative concepts in air traffic management and control. FAM 2.0 was developed by the Logistics Management Institute (LMI) under a National Aeronautics and Space Administration (NASA) contract. This document provides a technical description of FAM 2.0 and its computer files to enable the modeler and programmer to make enhancements or modifications to the model. Those interested in a guide for using the model in analysis should consult the companion document, Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 Users Manual.

Development of the Transport Class Model (TCM) Aircraft Simulation From a Sub-Scale Generic Transport Model (GTM) Simulation

NASA Technical Reports Server (NTRS)

Hueschen, Richard M.

2011-01-01

A six degree-of-freedom, flat-earth dynamics, non-linear, and non-proprietary aircraft simulation was developed that is representative of a generic mid-sized twin-jet transport aircraft. The simulation was developed from a non-proprietary, publicly available, subscale twin-jet transport aircraft simulation using scaling relationships and a modified aerodynamic database. The simulation has an extended aerodynamics database with aero data outside the normal transport-operating envelope (large angle-of-attack and sideslip values). The simulation has representative transport aircraft surface actuator models with variable rate-limits and generally fixed position limits. The simulation contains a generic 40,000 lb sea level thrust engine model. The engine model is a first order dynamic model with a variable time constant that changes according to simulation conditions. The simulation provides a means for interfacing a flight control system to use the simulation sensor variables and to command the surface actuators and throttle position of the engine model.

Aerodynamic Effects and Modeling of Damage to Transport Aircraft

NASA Technical Reports Server (NTRS)

Shah, Gautam H.

2008-01-01

A wind tunnel investigation was conducted to measure the aerodynamic effects of damage to lifting and stability/control surfaces of a commercial transport aircraft configuration. The modeling of such effects is necessary for the development of flight control systems to recover aircraft from adverse, damage-related loss-of-control events, as well as for the estimation of aerodynamic characteristics from flight data under such conditions. Damage in the form of partial or total loss of area was applied to the wing, horizontal tail, and vertical tail. Aerodynamic stability and control implications of damage to each surface are presented, to aid in the identification of potential boundaries in recoverable stability or control degradation. The aerodynamic modeling issues raised by the wind tunnel results are discussed, particularly the additional modeling requirements necessitated by asymmetries due to damage, and the potential benefits of such expanded modeling.

A Simulation Model to Evaluate Aircraft Survivability and Target Damage during Offensive Counterair Operations.

DTIC Science & Technology

1984-03-01

D-R14i 324 A SIMULATION MODEL TO EVALUATE AIRCRAFT SURVIVABILITY V/3 AND TARGET DAMAGE 0.. (U) AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL...MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS- 1963-A J.1 AFIT/GST/0S/84-18 TS I°TI w ’ i A SIMULATION MODEL TO E’VALLUATE AIRCRAFT...numberp Title: A SIMULATION MODEL TO EVALUATE AIRCRAFT SURVIVABILITY AND jARGET DAMAGE DURING OFFENSIVE COUNTERAIR OPERATIONS Thesis Chairma#: James R

U.S. aerospace industry opinion of the effect of computer-aided prediction-design technology on future wind-tunnel test requirements for aircraft development programs

NASA Technical Reports Server (NTRS)

Treon, S. L.

1979-01-01

A survey of the U.S. aerospace industry in late 1977 suggests that there will be an increasing use of computer-aided prediction-design technology (CPD Tech) in the aircraft development process but that, overall, only a modest reduction in wind-tunnel test requirements from the current level is expected in the period through 1995. Opinions were received from key spokesmen in 23 of the 26 solicited major companies or corporate divisions involved in the design and manufacture of nonrotary wing aircraft. Development programs for nine types of aircraft related to test phases and wind-tunnel size and speed range were considered.

Aircraft Maintenance Engineering: Factors Impacting Airlines E-Maintenance Technologies, Authoring and Illustrations

NASA Astrophysics Data System (ADS)

Karayianes, Frank

The purpose of this research was to evaluate factors influencing acceptance and use of technologies in the field of aircraft maintenance authoring, graphics, and documentation. Maintenance engineering authors convert complex engineering used in aircraft production and transform that data using technology (tools) into usable technical publications data. While the current literature includes a large volume of research in technology acceptance in various domains of industry and business, the problem is that no such studies exist with respect to the aircraft maintenance engineering authoring, allowing any number of tools to be used and acceptance to be unsure. The study was based on theoretical approaches of the Technology Acceptance Model and the associated hypothesis related to eight research questions. A survey questionnaire was developed for data collection from a selected population of aircraft maintenance engineering authors. Data collected from 148 responses were exposed to a range of statistical methods and analyses. Analysis of data were performed within the structural equation model using exploratory factor analysis, confirmatory factor analysis, and a range of regression methods. The analyses generally provided results consistent with prior literature. Two survey questions yielded unexpected results contrary to similar studies. The relationship between prior experience and job level did not show a significant relationship with perceived usefulness or perceived ease of use. Other results included the significant relationship between Perceived Usefulness and Perceived Ease of Use with Technology acceptance. Recommendations include understanding how Technology Acceptance can be improved for the industry and the need for further research not covered to refine recommendations for technology acceptance related to the aviation industry.

The NASA/industry Design Analysis Methods for Vibrations (DAMVIBS) program: Sikorsky Aircraft: Advances toward interacting with the airframe design process

NASA Technical Reports Server (NTRS)

Twomey, William J.

1993-01-01

A short history is traced of the work done at Sikorsky Aircraft under the NASA/industry DAMVIBS program. This includes both work directly funded by the program as well as work which was internally funded but which received its initial impetus from DAMVIBS. The development of a finite element model of the UH-60A airframe having a marked improvement in vibration-predicting ability is described. A new program, PAREDYM, developed at Sikorsky, which automatically adjusts an FEM so that its modal characteristics match test values, is described, as well as the part this program played in the improvement of the UH-60A model. Effects of the bungee suspension system on the shake test data used for model verification are described. The impetus given by the modeling improvement, as well as the recent availability of PAREDYM, has brought for the first time the introduction of low-vibration design into the design cycle at Sikorsky.

Assessing total fungal concentrations on commercial passenger aircraft using mixed-effects modeling.

PubMed

McKernan, Lauralynn Taylor; Hein, Misty J; Wallingford, Kenneth M; Burge, Harriet; Herrick, Robert

2008-01-01

The primary objective of this study was to compare airborne fungal concentrations onboard commercial passenger aircraft at various in-flight times with concentrations measured inside and outside airport terminals. A secondary objective was to investigate the use of mixed-effects modeling of repeat measures from multiple sampling intervals and locations. Sequential triplicate culturable and total spore samples were collected on wide-body commercial passenger aircraft (n = 12) in the front and rear of coach class during six sampling intervals: boarding, midclimb, early cruise, midcruise, late cruise, and deplaning. Comparison samples were collected inside and outside airport terminals at the origin and destination cities. The MIXED procedure in SAS was used to model the mean and the covariance matrix of the natural log transformed fungal concentrations. Five covariance structures were tested to determine the appropriate models for analysis. Fixed effects considered included the sampling interval and, for samples obtained onboard the aircraft, location (front/rear of coach section), occupancy rate, and carbon dioxide concentrations. Overall, both total culturable and total spore fungal concentrations were low while the aircraft were in flight. No statistical difference was observed between measurements made in the front and rear sections of the coach cabin for either culturable or total spore concentrations. Both culturable and total spore concentrations were significantly higher outside the airport terminal compared with inside the airport terminal (p-value < 0.0001) and inside the aircraft (p-value < 0.0001). On the aircraft, the majority of total fungal exposure occurred during the boarding and deplaning processes, when the aircraft utilized ancillary ventilation and passenger activity was at its peak.

Correlated Encounter Model for Cooperative Aircraft in the National Airspace System; Version 2.0

DTIC Science & Technology

2018-05-08

Lincoln Laboratory MASSACHUSETTS INSTITUTE OF TECHNOLOGY LEXINGTON, MASSACHUSETTS Project Report ATC-440 Correlated Encounter Model for...specifically authorized by the U.S. Government may violate any copyrights that exist in this work. Correlated Encounter Model for Cooperative Aircraft...2008 Correlated Encounter Model for Cooperative Aircraft (CEM) subsequently referred to as the Extended Correlated Encounter Model (ECEM). This model

Status of Computational Aerodynamic Modeling Tools for Aircraft Loss-of-Control

NASA Technical Reports Server (NTRS)

Frink, Neal T.; Murphy, Patrick C.; Atkins, Harold L.; Viken, Sally A.; Petrilli, Justin L.; Gopalarathnam, Ashok; Paul, Ryan C.

2016-01-01

A concerted effort has been underway over the past several years to evolve computational capabilities for modeling aircraft loss-of-control under the NASA Aviation Safety Program. A principal goal has been to develop reliable computational tools for predicting and analyzing the non-linear stability & control characteristics of aircraft near stall boundaries affecting safe flight, and for utilizing those predictions for creating augmented flight simulation models that improve pilot training. Pursuing such an ambitious task with limited resources required the forging of close collaborative relationships with a diverse body of computational aerodynamicists and flight simulation experts to leverage their respective research efforts into the creation of NASA tools to meet this goal. Considerable progress has been made and work remains to be done. This paper summarizes the status of the NASA effort to establish computational capabilities for modeling aircraft loss-of-control and offers recommendations for future work.

Aircraft/Air Traffic Management Functional Analysis Model. Version 2.0; User's Guide

NASA Technical Reports Server (NTRS)

Etheridge, Melvin; Plugge, Joana; Retina, Nusrat

1998-01-01

The Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 (FAM 2.0), is a discrete event simulation model designed to support analysis of alternative concepts in air traffic management and control. FAM 2.0 was developed by the Logistics Management Institute (LMI) a National Aeronautics and Space Administration (NASA) contract. This document provides a guide for using the model in analysis. Those interested in making enhancements or modification to the model should consult the companion document, Aircraft/Air Traffic Management Functional Analysis Model, Version 2.0 Technical Description.

A mathematical simulation model of a 1985-era tilt-rotor passenger aircraft

NASA Technical Reports Server (NTRS)

Mcveigh, M. A.; Widdison, C. A.

1976-01-01

A mathematical model for use in real-time piloted simulation of a 1985-era tilt rotor passenger aircraft is presented. The model comprises the basic six degrees-of-freedom equations of motion, and a large angle of attack representation of the airframe and rotor aerodynamics, together with equations and functions used to model turbine engine performance, aircraft control system and stability augmentation system. A complete derivation of the primary equations is given together with a description of the modeling techniques used. Data for the model is included in an appendix.

Use of simple models to determine wake vortex categories for new aircraft.

DOT National Transportation Integrated Search

2015-06-22

The paper describes how to use simple models and, if needed, sensitivity analyses to determine the wake vortex categories for new aircraft. The methodology provides a tool for the regulators to assess the relative risk of introducing new aircraft int...

Modeling Materials: Design for Planetary Entry, Electric Aircraft, and Beyond

NASA Technical Reports Server (NTRS)

Thompson, Alexander; Lawson, John W.

2014-01-01

NASA missions push the limits of what is possible. The development of high-performance materials must keep pace with the agency's demanding, cutting-edge applications. Researchers at NASA's Ames Research Center are performing multiscale computational modeling to accelerate development times and further the design of next-generation aerospace materials. Multiscale modeling combines several computationally intensive techniques ranging from the atomic level to the macroscale, passing output from one level as input to the next level. These methods are applicable to a wide variety of materials systems. For example: (a) Ultra-high-temperature ceramics for hypersonic aircraft-we utilized the full range of multiscale modeling to characterize thermal protection materials for faster, safer air- and spacecraft, (b) Planetary entry heat shields for space vehicles-we computed thermal and mechanical properties of ablative composites by combining several methods, from atomistic simulations to macroscale computations, (c) Advanced batteries for electric aircraft-we performed large-scale molecular dynamics simulations of advanced electrolytes for ultra-high-energy capacity batteries to enable long-distance electric aircraft service; and (d) Shape-memory alloys for high-efficiency aircraft-we used high-fidelity electronic structure calculations to determine phase diagrams in shape-memory transformations. Advances in high-performance computing have been critical to the development of multiscale materials modeling. We used nearly one million processor hours on NASA's Pleiades supercomputer to characterize electrolytes with a fidelity that would be otherwise impossible. For this and other projects, Pleiades enables us to push the physics and accuracy of our calculations to new levels.

Damage Propagation Modeling for Aircraft Engine Prognostics

NASA Technical Reports Server (NTRS)

Saxena, Abhinav; Goebel, Kai; Simon, Don; Eklund, Neil

2008-01-01

This paper describes how damage propagation can be modeled within the modules of aircraft gas turbine engines. To that end, response surfaces of all sensors are generated via a thermo-dynamical simulation model for the engine as a function of variations of flow and efficiency of the modules of interest. An exponential rate of change for flow and efficiency loss was imposed for each data set, starting at a randomly chosen initial deterioration set point. The rate of change of the flow and efficiency denotes an otherwise unspecified fault with increasingly worsening effect. The rates of change of the faults were constrained to an upper threshold but were otherwise chosen randomly. Damage propagation was allowed to continue until a failure criterion was reached. A health index was defined as the minimum of several superimposed operational margins at any given time instant and the failure criterion is reached when health index reaches zero. Output of the model was the time series (cycles) of sensed measurements typically available from aircraft gas turbine engines. The data generated were used as challenge data for the Prognostics and Health Management (PHM) data competition at PHM 08.

NASGRO 3.0: A Software for Analyzing Aging Aircraft

NASA Technical Reports Server (NTRS)

Mettu, S. R.; Shivakumar, V.; Beek, J. M.; Yeh, F.; Williams, L. C.; Forman, R. G.; McMahon, J. J.; Newman, J. C., Jr.

1999-01-01

Structural integrity analysis of aging aircraft is a critical necessity in view of the increasing numbers of such aircraft in general aviation, the airlines and the military. Efforts are in progress by NASA, the FAA and the DoD to focus attention on aging aircraft safety. The present paper describes the NASGRO software which is well-suited for effectively analyzing the behavior of defects that may be found in aging aircraft. The newly revised Version 3.0 has many features specifically implemented to suit the needs of the aircraft community. The fatigue crack growth computer program NASA/FLAGRO 2.0 was originally developed to analyze space hardware such as the Space Shuttle, the International Space Station and the associated payloads. Due to popular demand, the software was enhanced to suit the needs of the aircraft industry. Major improvements in Version 3.0 are the incorporation of the ability to read aircraft spectra of unlimited size, generation of common aircraft fatigue load blocks, and the incorporation of crack-growth models which include load-interaction effects such as retardation due to overloads and acceleration due to underloads. Five new crack-growth models, viz., generalized Willenborg, modified generalized Willenborg, constant closure model, Walker-Chang model and the deKoning-Newman strip-yield model, have been implemented. To facilitate easier input of geometry, material properties and load spectra, a Windows-style graphical user interface has been developed. Features to quickly change the input and rerun the problem as well as examine the output are incorporated. NASGRO has been organized into three modules, the crack-growth module being the primary one. The other two modules are the boundary element module and the material properties module. The boundary-element module provides the ability to model and analyze complex two-dimensional problems to obtain stresses and stress-intensity factors. The material properties module allows users to store and

Gottingen Wind Tunnel for Testing Aircraft Models

NASA Technical Reports Server (NTRS)

Prandtl, L

1920-01-01

Given here is a brief description of the Gottingen Wind Tunnel for the testing of aircraft models, preceded by a history of its development. Included are a number of diagrams illustrating, among other things, a sectional elevation of the wind tunnel, the pressure regulator, the entrance cone and method of supporting a model for simple drag tests, a three-component balance, and a propeller testing device, all of which are discussed in the text.

Seat Capacity Selection for an Advanced Short-Haul Aircraft Design

NASA Technical Reports Server (NTRS)

Marien, Ty V.

2016-01-01

A study was performed to determine the target seat capacity for a proposed advanced short-haul aircraft concept projected to enter the fleet by 2030. This analysis projected the potential demand in the U.S. for a short-haul aircraft using a transportation theory approach, rather than selecting a target seat capacity based on recent industry trends or current market demand. A transportation systems model was used to create a point-to-point network of short-haul trips and then predict the number of annual origin-destination trips on this network. Aircraft of varying seat capacities were used to meet the demand on this network, assuming a single aircraft type for the entire short-haul fleet. For each aircraft size, the ticket revenue and operational costs were used to calculate a total market profitability metric for all feasible flights. The different aircraft sizes were compared, based on this market profitability metric and also the total number of annual round trips and markets served. Sensitivity studies were also performed to determine the effect of changing the aircraft cruise speed and maximum trip length. Using this analysis, the advanced short-haul aircraft design team was able to select a target seat capacity for their design.

Analysis and optimization of preliminary aircraft configurations in relationship to emerging agility metrics

NASA Technical Reports Server (NTRS)

Sandlin, Doral R.; Bauer, Brent Alan

1993-01-01

This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition one study illustrates the module's ability to optimize a configuration's agility performance.

An Evaluation Technique for an F/A-18 Aircraft Loads Model Using F/A-18 Systems Research Aircraft Flight Data

NASA Technical Reports Server (NTRS)

Olney, Candida D.; Hillebrandt, Heather; Reichenbach, Eric Y.

2000-01-01

A limited evaluation of the F/A-18 baseline loads model was performed on the Systems Research Aircraft at NASA Dryden Flight Research Center (Edwards, California). Boeing developed the F/A-18 loads model using a linear aeroelastic analysis in conjunction with a flight simulator to determine loads at discrete locations on the aircraft. This experiment was designed so that analysis of doublets could be used to establish aircraft aerodynamic and loads response at 20 flight conditions. Instrumentation on the right outboard leading edge flap, left aileron, and left stabilator measured the hinge moment so that comparisons could be made between in-flight-measured hinge moments and loads model-predicted values at these locations. Comparisons showed that the difference between the loads model-predicted and in-flight-measured hinge moments was up to 130 percent of the flight limit load. A stepwise regression technique was used to determine new loads derivatives. These derivatives were placed in the loads model, which reduced the error to within 10 percent of the flight limit load. This paper discusses the flight test methodology, a process for determining loads coefficients, and the direct comparisons of predicted and measured hinge moments and loads coefficients.

Twist Model Development and Results from the Active Aeroelastic Wing F/A-18 Aircraft

NASA Technical Reports Server (NTRS)

Lizotte, Andrew M.; Allen, Michael J.

2007-01-01

Understanding the wing twist of the active aeroelastic wing (AAW) F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption. This technique produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.

Twist Model Development and Results From the Active Aeroelastic Wing F/A-18 Aircraft

NASA Technical Reports Server (NTRS)

Lizotte, Andrew; Allen, Michael J.

2005-01-01

Understanding the wing twist of the active aeroelastic wing F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption and by using neural networks. These techniques produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.

Aircraft

DTIC Science & Technology

2002-01-01

electronics, systems integration and information technology company.39 Northrop Grumman no longer seeks a position as a prime contractor/integrator of fixed...of the spares procurement and distribution processes. Finally, they recognize that excellence in Information Technology (IT) is a strategic advantage...business in export dollars, the industry has been forced to look for new markets as worldwide aircraft sales have dropped. Because the U.S. national

Aerodynamics of High-Lift Configuration Civil Aircraft Model in JAXA

NASA Astrophysics Data System (ADS)

Yokokawa, Yuzuru; Murayama, Mitsuhiro; Ito, Takeshi; Yamamoto, Kazuomi

This paper presents basic aerodynamics and stall characteristics of the high-lift configuration aircraft model JSM (JAXA Standard Model). During research process of developing high-lift system design method, wind tunnel testing at JAXA 6.5m by 5.5m low-speed wind tunnel and Navier-Stokes computation on unstructured hybrid mesh were performed for a realistic configuration aircraft model equipped with high-lift devices, fuselage, nacelle-pylon, slat tracks and Flap Track Fairings (FTF), which was assumed 100 passenger class modern commercial transport aircraft. The testing and the computation aimed to understand flow physics and then to obtain some guidelines for designing a high performance high-lift system. As a result of the testing, Reynolds number effects within linear region and stall region were observed. Analysis of static pressure distribution and flow visualization gave the knowledge to understand the aerodynamic performance. CFD could capture the whole characteristics of basic aerodynamics and clarify flow mechanism which governs stall characteristics even for complicated geometry and its flow field. This collaborative work between wind tunnel testing and CFD is advantageous for improving or has improved the aerodynamic performance.

Energy and emissions saving potential of additive manufacturing: the case of lightweight aircraft components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Runze; Riddle, Matthew; Graziano, Diane

Additive manufacturing (AM) holds great potential for improving materials efficiency, reducing life-cycle impacts, and enabling greater engineering functionality compared to conventional manufacturing (CM), and AM has been increasingly adopted by aircraft component manufacturers for lightweight, cost-effective designs. This study estimates the net changes in life-cycle primary energy and greenhouse gas emissions associated with AM technologies for lightweight metallic aircraft components through the year 2050, to shed light on the environmental benefits of a shift from CM to AM processes in the U.S. aircraft industry. A systems modeling framework is presented, with integrates engineering criteria, life-cycle environmental data, aircraft fleet stockmore » and fuel use models under different AM adoption scenarios. Estimated fleet-wide life-cycle primary energy savings at most reach 70-173 million GJ/year in 2050, with cumulative savings of 1.2–2.8 billion GJ. Associated cumulative GHG emission reductions were estimated at 92.1–215.0 million metric tons. In addition, thousands of tons of aluminum, titanium and nickel alloys could be potentially saved per year in 2050. The results indicate a significant role of AM technologies in helping society meet its long-term energy use and GHG emissions reduction goals, and highlight barriers and opportunities for AM adoption for the aircraft industry.« less

Aircraft radial-belted tire evaluation

NASA Technical Reports Server (NTRS)

Yager, Thomas J.; Stubbs, Sandy M.; Davis, Pamela A.

1990-01-01

An overview is given of the ongoing joint NASA/FAA/Industry Surface Traction And Radial Tire (START) Program being conducted at NASA Langley's Aircraft Landing Dynamics Facility (ALDF). The START Program involves tests using three different tire sizes to evaluate tire rolling resistance, braking, and cornering performance throughout the aircraft ground operational speed range for both dry and wet runway surfaces. Preliminary results from recent 40 x 14 size bias-ply, radial-belted, and H-type aircraft tire tests are discussed. The paper concludes with a summary of the current program status and planned ALDF test schedule.

Composite components on commercial aircraft

NASA Technical Reports Server (NTRS)

Dexter, H. B.

1980-01-01

Commercial aircraft manufacturers are making production commitments to composite structure for future aircraft and modifications to current production aircraft. Flight service programs with advanced composites sponsored by NASA during the past 10 years are described. Approximately 2.5 million total composite component flight hours have been accumulated since 1970 on both commercial transports and helicopters. Design concepts with significant mass savings were developed, appropriate inspection and maintenance procedures were established, and satisfactory service was achieved for the various composite components. A major NASA/U.S. industry technology program to reduce fuel consumption of commercial transport aircraft through the use of advanced composites was undertaken. Ground and flight environmental effects on the composite materials used in the flight service programs supplement the flight service evaluation.

Activities of NASA's Global Modeling Initiative (GMI) in the Assessment of Subsonic Aircraft Impact

NASA Technical Reports Server (NTRS)

Rodriquez, J. M.; Logan, J. A.; Rotman, D. A.; Bergmann, D. J.; Baughcum, S. L.; Friedl, R. R.; Anderson, D. E.

2004-01-01

The Intergovernmental Panel on Climate Change estimated a peak increase in ozone ranging from 7-12 ppbv (zonal and annual average, and relative to a baseline with no aircraft), due to the subsonic aircraft in the year 2015, corresponding to aircraft emissions of 1.3 TgN/year. This range of values presumably reflects differences in model input (e.g., chemical mechanism, ground emission fluxes, and meteorological fields), and algorithms. The model implemented by the Global Modeling Initiative allows testing the impact of individual model components on the assessment calculations. We present results of the impact of doubling the 1995 aircraft emissions of NOx, corresponding to an extra 0.56 TgN/year, utilizing meteorological data from NASA's Data Assimilation Office (DAO), the Goddard Institute for Space Studies (GISS), and the Middle Atmosphere Community Climate Model, version 3 (MACCM3). Comparison of results to observations can be used to assess the model performance. Peak ozone perturbations ranging from 1.7 to 2.2 ppbv of ozone are calculated using the different fields. These correspond to increases in total tropospheric ozone ranging from 3.3 to 4.1 Tg/Os. These perturbations are consistent with the IPCC results, due to the difference in aircraft emissions. However, the range of values calculated is much smaller than in IPCC.

Simulation model for the Boeing 720B aircraft-flight control system in continuous flight.

DOT National Transportation Integrated Search

1971-08-01

A mathematical model of the Boeing 720B aircraft and autopilot has been derived. The model is representative of the 720B aircraft for continuous flight within a flight envelope defined by a Mach number of .4 at 20,000 feet altitude in a cruise config...

Roll paper pilot. [mathematical model for predicting pilot rating of aircraft in roll task

NASA Technical Reports Server (NTRS)

Naylor, F. R.; Dillow, J. D.; Hannen, R. A.

1973-01-01

A mathematical model for predicting the pilot rating of an aircraft in a roll task is described. The model includes: (1) the lateral-directional aircraft equations of motion; (2) a stochastic gust model; (3) a pilot model with two free parameters; and (4) a pilot rating expression that is a function of rms roll angle and the pilot lead time constant. The pilot gain and lead time constant are selected to minimize the pilot rating expression. The pilot parameters are then adjusted to provide a 20% stability margin and the adjusted pilot parameters are used to compute a roll paper pilot rating of the aircraft/gust configuration. The roll paper pilot rating was computed for 25 aircraft/gust configurations. A range of actual ratings from 2 to 9 were encountered and the roll paper pilot ratings agree quite well with the actual ratings. In addition there is good correlation between predicted and measured rms roll angle.

Impact of Aircraft Emissions on Air Quality in the Vicinity of Airports. Volume I: Recent Airport Measurement Programs, Data Analyses, and Sub-Model Development

DTIC Science & Technology

1980-07-01

temperature has turbine stacks located in a region of high ambient turbu- - lence [Hoult (1975) and Egan (1975)]. I) I+ 110 4.5.4 Event Modeling Several...the aircraft industry in developing the gas turbine engine technology of the present era. Dispersion measurements permit determination of a power law...The ESEERCO Model for the Prediction of Plume Rise and Dispersion from Gas Turbine Engines. Air Pollution Control Association 68th Annual Meeting

Active control of interior noise in model aircraft fuselages using piezoceramic actuators

NASA Technical Reports Server (NTRS)

Fuller, C. R.; Hansen, C. H.; Silcox, R. J.; Snyder, S. D.

1990-01-01

Active control of interior noise in model aircraft fuselages using piezoceramic actuators is experimentally studied. The actuators are bonded directly to the structure and error information is taken from up to two microphones located in the interior acoustic field. The results demonstrate that global attenuation of the order of 10 to 15 dB of interior noise can be achieved with piezoceramic actuators, irrespective of whether the shell system is vibrating at an acoustic or structural resonant frequency. The work also proves that active control using vibration (moment) inputs works well when a floor simulating that of an aircraft is installed in the model. This result suggests that the technique will be successful in controlling interior noise in realistic aircraft structures.

NASA/aircraft industry standard specification for graphite fiber toughened thermoset resin composite material

NASA Technical Reports Server (NTRS)

1985-01-01

A standard specification for a selected class of graphite fiber/toughened thermoset resin matrix material was developed through joint NASA/Aircraft Industry effort. This specification was compiled to provide uniform requirements and tests for qualifying prepreg systems and for acceptance of prepreg batches. The specification applies specifically to a class of composite prepreg consisting of unidirectional graphite fibers impregnated with a toughened thermoset resin that produce laminates with service temperatures from -65 F to 200 F when cured at temperatures below or equal to 350 F. The specified prepreg has a fiber areal weight of 145 g sq m. The specified tests are limited to those required to set minimum standards for the uncured prepreg and cured laminates, and are not intended to provide design allowable properties.

Dynamic Modeling Accuracy Dependence on Errors in Sensor Measurements, Mass Properties, and Aircraft Geometry

NASA Technical Reports Server (NTRS)

Grauer, Jared A.; Morelli, Eugene A.

2013-01-01

A nonlinear simulation of the NASA Generic Transport Model was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of dynamic models identified from flight data. Measurements from a typical system identification maneuver were systematically and progressively deteriorated and then used to estimate stability and control derivatives within a Monte Carlo analysis. Based on the results, recommendations were provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using other flight conditions, parameter estimation methods, and a full-scale F-16 nonlinear aircraft simulation were compared with these recommendations.

Survivability Modeling & Simulation(Aircraft Survivability, Fall 2009)

DTIC Science & Technology

2009-01-01

Projects.” The Human Effectiveness Directorate is responsible for providing injury assessments for most modern Air Force ejection systems, for...developing ejection test mannequins, and for continuing to define human injury limits and criteria. The directorate maintains a man-rated horizontal...Using numerous models and testing, the directorate can define ejection /impact injury criteria for aircraft equipment to prevent personnel injuries

Update of aircraft profile data for the Integrated Noise Model computer program, vol 1: final report

DOT National Transportation Integrated Search

1992-03-01

This report provides aircraft takeoff and landing profiles, aircraft aerodynamic performance coefficients and engine performance coefficients for the aircraft data base (Database 9) in the Integrated Noise Model (INM) computer program. Flight profile...

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.

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.

Development and validation of a general purpose linearization program for rigid aircraft models

NASA Technical Reports Server (NTRS)

Duke, E. L.; Antoniewicz, R. F.

1985-01-01

A FORTRAN program that provides the user with a powerful and flexible tool for the linearization of aircraft models is discussed. The program LINEAR numerically determines a linear systems model using nonlinear equations of motion and a user-supplied, nonlinear aerodynamic model. The system model determined by LINEAR consists of matrices for both the state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model. Also, included in the report is a comparison of linear and nonlinear models for a high performance aircraft.

Modeling & Verifying Aircraft Paint Hangar Airflow to Reduce Green House Gas and Energy Usage while Protecting Occupational Health Energy

DTIC Science & Technology

2015-05-30

provides a smnmaty of results from the site visits and discusses areas of potential future research. 1S. SUBJECT TERMS Aircraft Paint Hangar...Airlift Wing ACCPFF ACGIH Aircraft Corrosion Control and Paint Finishing Facility American Conference of Governmental Industrial Hygienists ACS Cross...velocity did not increase exposure resulted in an interest in expanding the project to encompass more sites around the U.S. with support from the

World commercial aircraft accidents: 1st edition, 1946--1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, C.Y.

1992-02-01

This report is a compilation of all accidents world-wide involving aircraft in commercial service which resulted in the loss of the airframe or one or more fatality, or both. This information has been gathered in order to present a complete inventory of commercial aircraft accidents. Events involving military action, sabotage, terrorist bombings, hijackings, suicides, and industrial ground accidents are included within this list. This report is organized into six chapters. The first chapter is the introduction. The second chapter contains the compilation of accidents involving world commercial jet aircraft from 1952 to 1991. The third chapter presents a compilation ofmore » accidents involving world commercial turboprop aircraft from 1952 to 1991. The fourth chapter presents a compilation of accidents involving world commercial pistonprop aircraft with four or more engines from 1946 to 1991. Each accident compilation or database in chapters two, three and four is presented in chronological order. Each accident is presented with information the following categories: date of accident, airline or operator and its flight number (if known), type of flight, type of aircraft and model, aircraft registration number, construction number/manufacturers serial number, aircraft damage resulting from accident, accident flight phase, accident location, number of fatalities, number of occupants, references used to compile the information, and finally cause, remarks, or description (brief) of the accident. The fifth chapter presents a list of all commercial aircraft accidents for all aircraft types with 100 or more fatalities in order of decreasing number of fatalities. Chapter six presents the commercial aircraft accidents for all aircraft types by flight phase. Future editions of this report will have additional follow-on chapters which will present other studies still in preparation at the time this edition was being prepared.« less

Modeling Pilot State in Next Generation Aircraft Alert Systems

NASA Technical Reports Server (NTRS)

Carlin, Alan S.; Alexander, Amy L.; Schurr, Nathan

2011-01-01

The Next Generation Air Transportation System will introduce new, advanced sensor technologies into the cockpit that must convey a large number of potentially complex alerts. Our work focuses on the challenges associated with prioritizing aircraft sensor alerts in a quick and efficient manner, essentially determining when and how to alert the pilot This "alert decision" becomes very difficult in NextGen due to the following challenges: 1) the increasing number of potential hazards, 2) the uncertainty associated with the state of potential hazards as well as pilot slate , and 3) the limited time to make safely-critical decisions. In this paper, we focus on pilot state and present a model for anticipating duration and quality of pilot behavior, for use in a larger system which issues aircraft alerts. We estimate pilot workload, which we model as being dependent on factors including mental effort, task demands. and task performance. We perform a mathematically rigorous analysis of the model and resulting alerting plans. We simulate the model in software and present simulated results with respect to manipulation of the pilot measures.

Validation of Aircraft Noise Models at Lower Levels of Exposure

NASA Technical Reports Server (NTRS)

Page, Juliet A.; Plotkin, Kenneth J.; Carey, Jeffrey N.; Bradley, Kevin A.

1996-01-01

Noise levels around airports and airbases in the United States arc computed via the FAA's Integrated Noise Model (INM) or the Air Force's NOISEMAP (NMAP) program. These models were originally developed for use in the vicinity of airports, at distances which encompass a day night average sound level in decibels (Ldn) of 65 dB or higher. There is increasing interest in aircraft noise at larger distances from the airport. including en-route noise. To evaluate the applicability of INM and NMAP at larger distances, a measurement program was conducted at a major air carrier airport with monitoring sites located in areas exposed to an Ldn of 55 dB and higher. Automated Radar Terminal System (ARTS) radar tracking data were obtained to provide actual flight parameters and positive identification of aircraft. Flight operations were grouped according to aircraft type. stage length, straight versus curved flight tracks, and arrival versus departure. Sound exposure levels (SEL) were computed at monitoring locations, using the INM, and compared with measured values. While individual overflight SEL data was characterized by a high variance, analysis performed on an energy-averaging basis indicates that INM and similar models can be applied to regions exposed to an Ldn of 55 dB with no loss of reliability.

Prediction of aircraft handling qualities using analytical models of the human pilot

NASA Technical Reports Server (NTRS)

Hess, R. A.

1982-01-01

The optimal control model (OCM) of the human pilot is applied to the study of aircraft handling qualities. Attention is focused primarily on longitudinal tasks. The modeling technique differs from previous applications of the OCM in that considerable effort is expended in simplifying the pilot/vehicle analysis. After briefly reviewing the OCM, a technique for modeling the pilot controlling higher order systems is introduced. Following this, a simple criterion for determining the susceptibility of an aircraft to pilot-induced oscillations (PIO) is formulated. Finally, a model-based metric for pilot rating prediction is discussed. The resulting modeling procedure provides a relatively simple, yet unified approach to the study of a variety of handling qualities problems.

Prediction of aircraft handling qualities using analytical models of the human pilot

NASA Technical Reports Server (NTRS)

Hess, R. A.

1982-01-01

The optimal control model (OCM) of the human pilot is applied to the study of aircraft handling qualities. Attention is focused primarily on longitudinal tasks. The modeling technique differs from previous applications of the OCM in that considerable effort is expended in simplifying the pilot/vehicle analysis. After briefly reviewing the OCM, a technique for modeling the pilot controlling higher order systems is introduced. Following this, a simple criterion for determining the susceptibility of an aircraft to pilot induced oscillations is formulated. Finally, a model based metric for pilot rating prediction is discussed. The resulting modeling procedure provides a relatively simple, yet unified approach to the study of a variety of handling qualities problems.

14 CFR 61.319 - Can I operate a make and model of aircraft other than the make and model aircraft for which I...

Code of Federal Regulations, 2010 CFR

2010-01-01

... CERTIFICATION: PILOTS, FLIGHT INSTRUCTORS, AND GROUND INSTRUCTORS Sport Pilots § 61.319 Can I operate a make and... you hold a sport pilot certificate you may operate any make and model of light-sport aircraft in the...

ADS-B within a Multi-Aircraft Simulation for Distributed Air-Ground Traffic Management

NASA Technical Reports Server (NTRS)

Barhydt, Richard; Palmer, Michael T.; Chung, William W.; Loveness, Ghyrn W.

2004-01-01

Automatic Dependent Surveillance Broadcast (ADS-B) is an enabling technology for NASA s Distributed Air-Ground Traffic Management (DAG-TM) concept. DAG-TM has the goal of significantly increasing capacity within the National Airspace System, while maintaining or improving safety. Under DAG-TM, aircraft exchange state and intent information over ADS-B with other aircraft and ground stations. This information supports various surveillance functions including conflict detection and resolution, scheduling, and conformance monitoring. To conduct more rigorous concept feasibility studies, NASA Langley Research Center s PC-based Air Traffic Operations Simulation models a 1090 MHz ADS-B communication structure, based on industry standards for message content, range, and reception probability. The current ADS-B model reflects a mature operating environment and message interference effects are limited to Mode S transponder replies and ADS-B squitters. This model was recently evaluated in a Joint DAG-TM Air/Ground Coordination Experiment with NASA Ames Research Center. Message probability of reception vs. range was lower at higher traffic levels. The highest message collision probability occurred near the meter fix serving as the confluence for two arrival streams. Even the highest traffic level encountered in the experiment was significantly less than the industry standard "LA Basin 2020" scenario. Future studies will account for Mode A and C message interference (a major effect in several industry studies) and will include Mode A and C aircraft in the simulation, thereby increasing the total traffic level. These changes will support ongoing enhancements to separation assurance functions that focus on accommodating longer ADS-B information update intervals.

Modeling procedures for handling qualities evaluation of flexible aircraft

NASA Technical Reports Server (NTRS)

Govindaraj, K. S.; Eulrich, B. J.; Chalk, C. R.

1981-01-01

This paper presents simplified modeling procedures to evaluate the impact of flexible modes and the unsteady aerodynamic effects on the handling qualities of Supersonic Cruise Aircraft (SCR). The modeling procedures involve obtaining reduced order transfer function models of SCR vehicles, including the important flexible mode responses and unsteady aerodynamic effects, and conversion of the transfer function models to time domain equations for use in simulations. The use of the modeling procedures is illustrated by a simple example.

Application of thermochemical modeling to aircraft interior polymeric materials

DOT National Transportation Integrated Search

1982-06-01

This report summarizes the results from a twelve-month study of the feasibility of applying certain basic concepts in the thermochemical modeling to aircraft cabin fire safety. The concepts developed earlier on a NASA-sponsored program were applied t...

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.

Smart aircraft fastener evaluation (SAFE) system: a condition-based corrosion detection system for aging aircraft

NASA Astrophysics Data System (ADS)

Schoess, Jeffrey N.; Seifert, Greg; Paul, Clare A.

1996-05-01

The smart aircraft fastener evaluation (SAFE) system is an advanced structural health monitoring effort to detect and characterize corrosion in hidden and inaccessible locations of aircraft structures. Hidden corrosion is the number one logistics problem for the U.S. Air Force, with an estimated maintenance cost of $700M per year in 1990 dollars. The SAFE system incorporates a solid-state electrochemical microsensor and smart sensor electronics in the body of a Hi-Lok aircraft fastener to process and autonomously report corrosion status to aircraft maintenance personnel. The long-term payoff for using SAFE technology will be in predictive maintenance for aging aircraft and rotorcraft systems, fugitive emissions applications such as control valves, chemical pipeline vessels, and industrial boilers. Predictive maintenance capability, service, and repair will replace the current practice of scheduled maintenance to substantially reduce operational costs. A summary of the SAFE concept, laboratory test results, and future field test plans is presented.

Simulation Model for the Piper PA-30 Light Maneuverable Aircraft in the Final Approach

DOT National Transportation Integrated Search

1971-07-01

The report describes the Piper PA-30 'Twin Comanche' aircraft and a representative autopilot during the final approach configuration for simulation purposes. The aircraft is modeled by linearized six-degree-of-freedom perturbation equations reference...

Dependence of Dynamic Modeling Accuracy on Sensor Measurements, Mass Properties, and Aircraft Geometry

NASA Technical Reports Server (NTRS)

Grauer, Jared A.; Morelli, Eugene A.

2013-01-01

The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations

Turbulence modeling of free shear layers for high-performance aircraft

NASA Technical Reports Server (NTRS)

Sondak, Douglas L.

1993-01-01

The High Performance Aircraft (HPA) Grand Challenge of the High Performance Computing and Communications (HPCC) program involves the computation of the flow over a high performance aircraft. A variety of free shear layers, including mixing layers over cavities, impinging jets, blown flaps, and exhaust plumes, may be encountered in such flowfields. Since these free shear layers are usually turbulent, appropriate turbulence models must be utilized in computations in order to accurately simulate these flow features. The HPCC program is relying heavily on parallel computers. A Navier-Stokes solver (POVERFLOW) utilizing the Baldwin-Lomax algebraic turbulence model was developed and tested on a 128-node Intel iPSC/860. Algebraic turbulence models run very fast, and give good results for many flowfields. For complex flowfields such as those mentioned above, however, they are often inadequate. It was therefore deemed that a two-equation turbulence model will be required for the HPA computations. The k-epsilon two-equation turbulence model was implemented on the Intel iPSC/860. Both the Chien low-Reynolds-number model and a generalized wall-function formulation were included.

Greedy Sampling and Incremental Surrogate Model-Based Tailoring of Aeroservoelastic Model Database for Flexible Aircraft

NASA Technical Reports Server (NTRS)

Wang, Yi; Pant, Kapil; Brenner, Martin J.; Ouellette, Jeffrey A.

2018-01-01

This paper presents a data analysis and modeling framework to tailor and develop linear parameter-varying (LPV) aeroservoelastic (ASE) model database for flexible aircrafts in broad 2D flight parameter space. The Kriging surrogate model is constructed using ASE models at a fraction of grid points within the original model database, and then the ASE model at any flight condition can be obtained simply through surrogate model interpolation. The greedy sampling algorithm is developed to select the next sample point that carries the worst relative error between the surrogate model prediction and the benchmark model in the frequency domain among all input-output channels. The process is iterated to incrementally improve surrogate model accuracy till a pre-determined tolerance or iteration budget is met. The methodology is applied to the ASE model database of a flexible aircraft currently being tested at NASA/AFRC for flutter suppression and gust load alleviation. Our studies indicate that the proposed method can reduce the number of models in the original database by 67%. Even so the ASE models obtained through Kriging interpolation match the model in the original database constructed directly from the physics-based tool with the worst relative error far below 1%. The interpolated ASE model exhibits continuously-varying gains along a set of prescribed flight conditions. More importantly, the selected grid points are distributed non-uniformly in the parameter space, a) capturing the distinctly different dynamic behavior and its dependence on flight parameters, and b) reiterating the need and utility for adaptive space sampling techniques for ASE model database compaction. The present framework is directly extendible to high-dimensional flight parameter space, and can be used to guide the ASE model development, model order reduction, robust control synthesis and novel vehicle design of flexible aircraft.

Preliminary noise tradeoff study of a Mach 2.7 cruise aircraft

NASA Technical Reports Server (NTRS)

Mascitti, V. R.; Maglieri, D. J. (Editor); Raney, J. P. (Editor)

1979-01-01

NASA computer codes in the areas of preliminary sizing and enroute performance, takeoff and landing performance, aircraft noise prediction, and economics were used in a preliminary noise tradeoff study for a Mach 2.7 design supersonic cruise concept. Aerodynamic configuration data were based on wind-tunnel model tests and related analyses. Aircraft structural characteristics and weight were based on advanced structural design methodologies, assuming conventional titanium technology. The most advanced noise prediction techniques available were used, and aircraft operating costs were estimated using accepted industry methods. The 4-engines cycles included in the study were based on assumed 1985 technology levels. Propulsion data was provided by aircraft manufacturers. Additional empirical data is needed to define both noise reduction features and other operating characteristics of all engine cycles under study. Data on VCE design parameters, coannular nozzle inverted flow noise reduction and advanced mechanical suppressors are urgently needed to reduce the present uncertainties in studies of this type.

Industrial approach to piezoelectric damping of large fighter aircraft components

NASA Astrophysics Data System (ADS)

Simpson, John; Schweiger, Johannes

1998-06-01

Different concepts to damp structural vibrations of the vertical tail of fighter aircraft are reported. The various requirements for a vertical tail bias an integrated approach for the design. Several active vibrations suppression concepts had been investigated during the preparatory phase of a research program shared by Daimler-Benz Aerospace Military Aircraft (Dasa), Daimler-Benz Forschung (DBF) and Deutsche Forschungsandstalt fuer Luftund Raumfahrt (DLR). Now in the main phase of the programme, four concepts were finally chosen: two concepts with aerodynamic control surfaces and two concepts with piezoelectric components. One piezo concept approach will be described rigorously, the other concepts are briefly addressed. In the Dasa concept, thin surface piezo actuators are set out carefully to flatten the dynamic portion of the combined static and dynamic maximum bending moment loading case directly in the shell structure. The second piezo concept by DLR involves pre-loaded lead zirconate titanate (PZT)-block actuators at host structure fixtures. To this end a research apparatus was designed and built as a full scale simplified fin box with carbon fiber reinformed plastic skins and an aluminium stringer-rib substructure restrained by relevant aircraft fixtures. It constitutes a benchmark 3D-structural impedance. The engineering design incorporates 7kg of PZT surface actuators. The structural system then should be excited to more than 15mm tip displacement amplitude. This prepares the final step to total A/C integration. Typical analysis methods using cyclic thermal analogies adapted to induced load levels are compared. Commercial approaches leading onto basic state space model interpretation wrt. actuator sizing and positioning, structural integrity constraints, FE-validation and testing are described. Both piezoelectric strategies are aimed at straight open-loop performance related to concept weight penalty and input electric power. The required actuators, power

Strength of Welded Joints in Tubular Members for Aircraft

NASA Technical Reports Server (NTRS)

Whittemore, H L; Brueggeman, W C

1931-01-01

The object of this investigation is to make available to the aircraft industry authoritative information on the strength, weight, and cost of a number of types of welded joints. This information will, also, assist the aeronautics branch in its work of licensing planes by providing data from which the strength of a given joint may be estimated. As very little material on the strength of aircraft welds has been published, it is believed that such tests made by a disinterested governmental laboratory should be of considerable value to the aircraft industry. Forty joints were welded under procedure specifications and tested to determine their strengths. The weight and time required to fabricate were also measured for each joint.

A 3D Model to Compute Lightning and HIRF Coupling Effects on Avionic Equipment of an Aircraft

NASA Astrophysics Data System (ADS)

Perrin, E.; Tristant, F.; Guiffaut, C.; Terrade, F.; Reineix, A.

2012-05-01

This paper describes the 3D FDTD model of an aircraft developed to compute the lightning and HIRF (High Intentity Radiated Fields) coupling effects on avionic equipment and all the wire harness associated. This virtual prototype aims at assisting the aircraft manufacturer during the lightning and HIRF certification processes. The model presented here permits to cover a frequency range from lightning spectrum to the low frequency HIRF domain, i.e. 0 to 100 MHz. Moreover, the entire aircraft, including the frame, the skin, the wire harness and the equipment are taken into account in only one model. Results obtained are compared to measurements on a real aircraft.

Design Sensitivity for a Subsonic Aircraft Predicted by Neural Network and Regression Models

NASA Technical Reports Server (NTRS)

Hopkins, Dale A.; Patnaik, Surya N.

2005-01-01

A preliminary methodology was obtained for the design optimization of a subsonic aircraft by coupling NASA Langley Research Center s Flight Optimization System (FLOPS) with NASA Glenn Research Center s design optimization testbed (COMETBOARDS with regression and neural network analysis approximators). The aircraft modeled can carry 200 passengers at a cruise speed of Mach 0.85 over a range of 2500 n mi and can operate on standard 6000-ft takeoff and landing runways. The design simulation was extended to evaluate the optimal airframe and engine parameters for the subsonic aircraft to operate on nonstandard runways. Regression and neural network approximators were used to examine aircraft operation on runways ranging in length from 4500 to 7500 ft.

Analytical model for investigation of interior noise characteristics in aircraft with multiple propellers including synchrophasing

NASA Technical Reports Server (NTRS)

Fuller, C. R.

1986-01-01

A simplified analytical model of transmission of noise into the interior of propeller-driven aircraft has been developed. The analysis includes directivity and relative phase effects of the propeller noise sources, and leads to a closed form solution for the coupled motion between the interior and exterior fields via the shell (fuselage) vibrational response. Various situations commonly encountered in considering sound transmission into aircraft fuselages are investigated analytically and the results obtained are compared to measurements in real aircraft. In general the model has proved successful in identifying basic mechanisms behind noise transmission phenomena.

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.

Aircraft Airframe Cost Estimation Using a Random Coefficients Model

DTIC Science & Technology

1979-12-01

approach will also be used here. 2 Model Formulation Several different types of equations could be used for the basic form of the CER, such as linear ...5) Marcotte developed several CER’s for fighter aircraft airframes using the log- linear model . A plot of the residuals from the CER for recurring...of the natural logarithm. Ordinary Least Squares The ordinary least squares procedure starts with the equation for the general linear model . The

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.

New developments in aluminum for aircraft and automobiles

NASA Technical Reports Server (NTRS)

Petit, Jocelyn I.

1994-01-01

A common bond for the aircraft and automobile industry is the need for cost-efficient, lightweight structures such as provided by aluminum based materials. The topics are presented in viewgraph form and cover the following: new developments in aluminum for aircraft and automobiles; forces shaping future automotive materials needs; aluminum strength/weakness versus competitive materials; evolution of aluminum aerospace alloys; forces shaping future aircraft materials needs; fiber/metal structural laminates; and property requirements for jetliner and military transport applications.

Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

NASA Technical Reports Server (NTRS)

Bauer, Brent

1993-01-01

This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

Aircraft requirements for low/medium density markets

NASA Technical Reports Server (NTRS)

Ausrotas, R.; Dodge, S.; Faulkner, H.; Glendinning, I.; Hays, A.; Simpson, R.; Swan, W.; Taneja, N.; Vittek, J.

1973-01-01

A study was conducted to determine the demand for and the economic factors involved in air transportation in a low and medium density market. The subjects investigated are as follows: (1) industry and market structure, (2) aircraft analysis, (3) economic analysis, (4) field surveys, and (5) computer network analysis. Graphs are included to show the economic requirements and the aircraft performance characteristics.

Highly integrated digital electronic control: Digital flight control, aircraft model identification, and adaptive engine control

NASA Technical Reports Server (NTRS)

Baer-Riedhart, Jennifer L.; Landy, Robert J.

1987-01-01

The highly integrated digital electronic control (HIDEC) program at NASA Ames Research Center, Dryden Flight Research Facility is a multiphase flight research program to quantify the benefits of promising integrated control systems. McDonnell Aircraft Company is the prime contractor, with United Technologies Pratt and Whitney Aircraft, and Lear Siegler Incorporated as major subcontractors. The NASA F-15A testbed aircraft was modified by the HIDEC program by installing a digital electronic flight control system (DEFCS) and replacing the standard F100 (Arab 3) engines with F100 engine model derivative (EMD) engines equipped with digital electronic engine controls (DEEC), and integrating the DEEC's and DEFCS. The modified aircraft provides the capability for testing many integrated control modes involving the flight controls, engine controls, and inlet controls. This paper focuses on the first two phases of the HIDEC program, which are the digital flight control system/aircraft model identification (DEFCS/AMI) phase and the adaptive engine control system (ADECS) phase.

Aircraft Engine Systems

NASA Technical Reports Server (NTRS)

Veres, Joseph P.

2003-01-01

The objective is to develop the capability to numerically model the performance of gas turbine engines used for aircraft propulsion. This capability will provide turbine engine designers with a means of accurately predicting the performance of new engines in a system environment prior to building and testing. The 'numerical test cell' developed under this project will reduce the number of component and engine tests required during development. As a result, the project will help to reduce the design cycle time and cost of gas turbine engines. This capability will be distributed to U.S. turbine engine manufacturers and air framers. This project focuses on goals of maintaining U.S. superiority in commercial gas turbine engine development for the aeronautics industry.

Math modeling and computer mechanization for real time simulation of rotary-wing aircraft

NASA Technical Reports Server (NTRS)

Howe, R. M.

1979-01-01

Mathematical modeling and computer mechanization for real time simulation of rotary wing aircraft is discussed. Error analysis in the digital simulation of dynamic systems, such as rotary wing aircraft is described. The method for digital simulation of nonlinearities with discontinuities, such as exist in typical flight control systems and rotor blade hinges, is discussed.

Fuzzy Model-based Pitch Stabilization and Wing Vibration Suppression of Flexible Wing Aircraft.

NASA Technical Reports Server (NTRS)

Ayoubi, Mohammad A.; Swei, Sean Shan-Min; Nguyen, Nhan T.

2014-01-01

This paper presents a fuzzy nonlinear controller to regulate the longitudinal dynamics of an aircraft and suppress the bending and torsional vibrations of its flexible wings. The fuzzy controller utilizes full-state feedback with input constraint. First, the Takagi-Sugeno fuzzy linear model is developed which approximates the coupled aeroelastic aircraft model. Then, based on the fuzzy linear model, a fuzzy controller is developed to utilize a full-state feedback and stabilize the system while it satisfies the control input constraint. Linear matrix inequality (LMI) techniques are employed to solve the fuzzy control problem. Finally, the performance of the proposed controller is demonstrated on the NASA Generic Transport Model (GTM).

The NASA aircraft icing research program

NASA Technical Reports Server (NTRS)

Shaw, Robert J.; Reinmann, John J.

1990-01-01

The objective of the NASA aircraft icing research program is to develop and make available to industry icing technology to support the needs and requirements for all-weather aircraft designs. Research is being done for both fixed wing and rotary wing applications. The NASA program emphasizes technology development in two areas, advanced ice protection concepts and icing simulation. Reviewed here are the computer code development/validation, icing wind tunnel testing, and icing flight testing efforts.

Energy and emissions saving potential of additive manufacturing: the case of lightweight aircraft components

DOE PAGES

Huang, Runze; Riddle, Matthew; Graziano, Diane; ...

2015-05-08

Additive manufacturing (AM) holds great potential for improving materials efficiency, reducing life-cycle impacts, and enabling greater engineering functionality compared to conventional manufacturing (CM) processes. For these reasons, AM has been adopted by a growing number of aircraft component manufacturers to achieve more lightweight, cost-effective designs. This study estimates the net changes in life-cycle primary energy and greenhouse gas emissions associated with AM technologies for lightweight metallic aircraft components through the year 2050, to shed light on the environmental benefits of a shift from CM to AM processes in the U.S. aircraft industry. A systems modeling framework is presented, with integratesmore » engineering criteria, life-cycle environmental data, and aircraft fleet stock and fuel use models under different AM adoption scenarios. Estimated fleetwide life-cycle primary energy savings in a rapid adoption scenario reach 70-174 million GJ/year in 2050, with cumulative savings of 1.2-2.8 billion GJ. Associated cumulative emission reduction potentials of CO2e were estimated at 92.8-217.4 million metric tons. About 95% of the savings is attributed to airplane fuel consumption reductions due to lightweighting. In addition, about 4050 tons aluminum, 7600 tons titanium and 8100 tons of nickel alloys could be saved per year in 2050. The results indicate a significant role of AM technologies in helping society meet its long-term energy use and GHG emissions reduction goals, and highlight barriers and opportunities for AM adoption for the aircraft industry.« less

Energy and emissions saving potential of additive manufacturing: the case of lightweight aircraft components

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Runze; Riddle, Matthew; Graziano, Diane

Additive manufacturing (AM) holds great potential for improving materials efficiency, reducing life-cycle impacts, and enabling greater engineering functionality compared to conventional manufacturing (CM) processes. For these reasons, AM has been adopted by a growing number of aircraft component manufacturers to achieve more lightweight, cost-effective designs. This study estimates the net changes in life-cycle primary energy and greenhouse gas emissions associated with AM technologies for lightweight metallic aircraft components through the year 2050, to shed light on the environmental benefits of a shift from CM to AM processes in the U.S. aircraft industry. A systems modeling framework is presented, with integratesmore » engineering criteria, life-cycle environmental data, and aircraft fleet stock and fuel use models under different AM adoption scenarios. Estimated fleetwide life-cycle primary energy savings in a rapid adoption scenario reach 70-174 million GJ/year in 2050, with cumulative savings of 1.2-2.8 billion GJ. Associated cumulative emission reduction potentials of CO2e were estimated at 92.8-217.4 million metric tons. About 95% of the savings is attributed to airplane fuel consumption reductions due to lightweighting. In addition, about 4050 tons aluminum, 7600 tons titanium and 8100 tons of nickel alloys could be saved per year in 2050. The results indicate a significant role of AM technologies in helping society meet its long-term energy use and GHG emissions reduction goals, and highlight barriers and opportunities for AM adoption for the aircraft industry.« less

Flight Dynamics Modeling and Simulation of a Damaged Transport Aircraft

NASA Technical Reports Server (NTRS)

Shah, Gautam H.; Hill, Melissa A.

2012-01-01

A study was undertaken at NASA Langley Research Center to establish, demonstrate, and apply methodology for modeling and implementing the aerodynamic effects of MANPADS damage to a transport aircraft into real-time flight simulation, and to demonstrate a preliminary capability of using such a simulation to conduct an assessment of aircraft survivability. Key findings from this study include: superpositioning of incremental aerodynamic characteristics to the baseline simulation aerodynamic model proved to be a simple and effective way of modeling damage effects; the primary effect of wing damage rolling moment asymmetry may limit minimum airspeed for adequate controllability, but this can be mitigated by the use of sideslip; combined effects of aerodynamics, control degradation, and thrust loss can result in significantly degraded controllability for a safe landing; and high landing speeds may be required to maintain adequate control if large excursions from the nominal approach path are allowed, but high-gain pilot control during landing can mitigate this risk.

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.

Physiological consequences of rapid or prolonged aircraft decompression: evaluation using a human respiratory model.

PubMed

Wolf, Matthew

2014-04-01

Aircraft passengers and crew may be subjected to rapid or prolonged decompression to high cabin altitude when an aircraft develops a hole in the fuselage. The accepted measure of neurological damage due to the hypobaric hypoxia produced is the subjective 'time of useful consciousness' (TUC) measure, which is appropriate for pilots and crew who perform their given tasks, however, TUC is measured under conditions different than the decompression scenarios that passengers undergo in today's aircraft. Ernsting proposed that prolonged exposure to alveolar O2 pressures less than 30 mmHg (P30) causes neurological damage. The current study proposes that a critical value of arterial O2 saturation of 70% (S70) can be used in place of P30 and that this physiological measure is more suited for determination of hypobaric hypoxia in passengers. The study shows the equivalence of model-predicted P30 and S70 values in the Ernsting-decompression scenarios. The model is also used to predict values of these physiological measures in actual aircraft-decompression scenarios. The model can be used by others to quantitatively predict the degree of hypobaric hypoxia for virtually any kind of decompression scenario, including those where supplemental O2 is used. Use of this tool avoids the prohibitive costs of human-subject testing for new aircraft and the potential danger inherent in such tests.

Unified Theory for Aircraft Handling Qualities and Adverse Aircraft-Pilot Coupling

NASA Technical Reports Server (NTRS)

Hess, R. A.

1997-01-01

A unified theory for aircraft handling qualities and adverse aircraft-pilot coupling or pilot-induced oscillations is introduced. The theory is based on a structural model of the human pilot. A methodology is presented for the prediction of (1) handling qualities levels; (2) pilot-induced oscillation rating levels; and (3) a frequency range in which pilot-induced oscillations are likely to occur. Although the dynamics of the force-feel system of the cockpit inceptor is included, the methodology will not account for effects attributable to control sensitivity and is limited to single-axis tasks and, at present, to linear vehicle models. The theory is derived from the feedback topology of the structural model and an examination of flight test results for 32 aircraft configurations simulated by the U.S. Air Force/CALSPAN NT-33A and Total In-Flight Simulator variable stability aircraft. An extension to nonlinear vehicle dynamics such as that encountered with actuator saturation is discussed.

Coupled Vortex-Lattice Flight Dynamic Model with Aeroelastic Finite-Element Model of Flexible Wing Transport Aircraft with Variable Camber Continuous Trailing Edge Flap for Drag Reduction

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; Ting, Eric; Nguyen, Daniel; Dao, Tung; Trinh, Khanh

2013-01-01

This paper presents a coupled vortex-lattice flight dynamic model with an aeroelastic finite-element model to predict dynamic characteristics of a flexible wing transport aircraft. The aircraft model is based on NASA Generic Transport Model (GTM) with representative mass and stiffness properties to achieve a wing tip deflection about twice that of a conventional transport aircraft (10% versus 5%). This flexible wing transport aircraft is referred to as an Elastically Shaped Aircraft Concept (ESAC) which is equipped with a Variable Camber Continuous Trailing Edge Flap (VCCTEF) system for active wing shaping control for drag reduction. A vortex-lattice aerodynamic model of the ESAC is developed and is coupled with an aeroelastic finite-element model via an automated geometry modeler. This coupled model is used to compute static and dynamic aeroelastic solutions. The deflection information from the finite-element model and the vortex-lattice model is used to compute unsteady contributions to the aerodynamic force and moment coefficients. A coupled aeroelastic-longitudinal flight dynamic model is developed by coupling the finite-element model with the rigid-body flight dynamic model of the GTM.

Influence of Implementation of Composite Materials in Civil Aircraft Industry on reduction of Environmental Pollution and Greenhouse Effect

NASA Astrophysics Data System (ADS)

Beck, A. J.; Hodzic, A.; Soutis, C.; Wilson, C. W.

2011-12-01

Computer-based Life Cycle Analysis (LCA) models were carried out to compare lightweight composites with the traditional aluminium over their useful lifetime. The analysis included raw materials, production, useful life in operation and disposal at the end of the material's useful life. The carbon fibre epoxy resin composite could in some cases reduce the weight of a component by up to 40 % compared to aluminium. As the fuel consumption of an aircraft is strongly influenced by its total weight, the emissions can be significantly reduced by increasing the proportion of composites used in the aircraft structure. Higher emissions, compared to aluminium, produced during composites production meet their 'break even' point after certain number of time units when used in aircraft structures, and continue to save emissions over their long-term operation. The study highlighted the environmental benefits of using lightweight structures in aircraft design, and also showed that utilisation of composites in products without energy saving may lead to increased emissions in the environment.

Multi-level systems modeling and optimization for novel aircraft

NASA Astrophysics Data System (ADS)

Subramanian, Shreyas Vathul

This research combines the disciplines of system-of-systems (SoS) modeling, platform-based design, optimization and evolving design spaces to achieve a novel capability for designing solutions to key aeronautical mission challenges. A central innovation in this approach is the confluence of multi-level modeling (from sub-systems to the aircraft system to aeronautical system-of-systems) in a way that coordinates the appropriate problem formulations at each level and enables parametric search in design libraries for solutions that satisfy level-specific objectives. The work here addresses the topic of SoS optimization and discusses problem formulation, solution strategy, the need for new algorithms that address special features of this problem type, and also demonstrates these concepts using two example application problems - a surveillance UAV swarm problem, and the design of noise optimal aircraft and approach procedures. This topic is critical since most new capabilities in aeronautics will be provided not just by a single air vehicle, but by aeronautical Systems of Systems (SoS). At the same time, many new aircraft concepts are pressing the boundaries of cyber-physical complexity through the myriad of dynamic and adaptive sub-systems that are rising up the TRL (Technology Readiness Level) scale. This compositional approach is envisioned to be active at three levels: validated sub-systems are integrated to form conceptual aircraft, which are further connected with others to perform a challenging mission capability at the SoS level. While these multiple levels represent layers of physical abstraction, each discipline is associated with tools of varying fidelity forming strata of 'analysis abstraction'. Further, the design (composition) will be guided by a suitable hierarchical complexity metric formulated for the management of complexity in both the problem (as part of the generative procedure and selection of fidelity level) and the product (i.e., is the mission

Flight Controller Software Protects Lightweight Flexible Aircraft

NASA Technical Reports Server (NTRS)

2015-01-01

Lightweight flexible aircraft may be the future of aviation, but a major problem is their susceptibility to flutter-uncontrollable vibrations that can destroy wings. Armstrong Flight Research Center awarded SBIR funding to Minneapolis, Minnesota-based MUSYN Inc. to develop software that helps program flight controllers to suppress flutter. The technology is now available for aircraft manufacturers and other industries that use equipment with automated controls.

Validation of Aircraft Noise Prediction Models at Low Levels of Exposure

NASA Technical Reports Server (NTRS)

Page, Juliet A.; Hobbs, Christopher M.; Plotkin, Kenneth J.; Stusnick, Eric; Shepherd, Kevin P. (Technical Monitor)

2000-01-01

Aircraft noise measurements were made at Denver International Airport for a period of four weeks. Detailed operational information was provided by airline operators which enabled noise levels to be predicted using the FAA's Integrated Noise Model. Several thrust prediction techniques were evaluated. Measured sound exposure levels for departure operations were found to be 4 to 10 dB higher than predicted, depending on the thrust prediction technique employed. Differences between measured and predicted levels are shown to be related to atmospheric conditions present at the aircraft altitude.

A measurement model for general noise reaction in response to aircraft noise.

PubMed

Kroesen, Maarten; Schreckenberg, Dirk

2011-01-01

In this paper a measurement model for general noise reaction (GNR) in response to aircraft noise is developed to assess the performance of aircraft noise annoyance and a direct measure of general reaction as indicators of this concept. For this purpose GNR is conceptualized as a superordinate latent construct underlying particular manifestations. This conceptualization is empirically tested through estimation of a second-order factor model. Data from a community survey at Frankfurt Airport are used for this purpose (N=2206). The data fit the hypothesized factor structure well and support the conceptualization of GNR as a superordinate construct. It is concluded that noise annoyance and a direct measure of general reaction to noise capture a large part of the negative feelings and emotions in response to aircraft noise but are unable to capture all relevant variance. The paper concludes with recommendations for the valid measurement of community reaction and several directions for further research.

A Survey of the Aircraft Maintenance Industry to Solicit Perceptions Regarding the Effectiveness of Recent Graduates of F.A.A. Approved Maintenance Schools.

ERIC Educational Resources Information Center

O'Brian, Benjamin H.

A study examined the perceptions of employers in the aircraft maintenance industry regarding the effectiveness of recent graduates of Federal Aeronautics Administration (FAA)-approved maintenance schools. Of the 100 employers who were contacted, 68 returned usable surveys. Based on responses, it was concluded that the views of employers in the…

Multi-objective decision-making model based on CBM for an aircraft fleet

NASA Astrophysics Data System (ADS)

Luo, Bin; Lin, Lin

2018-04-01

Modern production management patterns, in which multi-unit (e.g., a fleet of aircrafts) are managed in a holistic manner, have brought new challenges for multi-unit maintenance decision making. To schedule a good maintenance plan, not only does the individual machine maintenance have to be considered, but also the maintenance of the other individuals have to be taken into account. Since most condition-based maintenance researches for aircraft focused on solely reducing maintenance cost or maximizing the availability of single aircraft, as well as considering that seldom researches concentrated on both the two objectives: minimizing cost and maximizing the availability of a fleet (total number of available aircraft in fleet), a multi-objective decision-making model based on condition-based maintenance concentrated both on the above two objectives is established. Furthermore, in consideration of the decision maker may prefer providing the final optimal result in the form of discrete intervals instead of a set of points (non-dominated solutions) in real decision-making problem, a novel multi-objective optimization method based on support vector regression is proposed to solve the above multi-objective decision-making model. Finally, a case study regarding a fleet is conducted, with the results proving that the approach efficiently generates outcomes that meet the schedule requirements.

Representative Stall Model of Regional Aircraft for Simulator Training Using a Spline Shape Prescriptive Modeling Approach

NASA Astrophysics Data System (ADS)

Zhang, Tony S.

Loss-of-control following aerodynamic stall remains the largest contributor to fatal civil aviation accidents. Aerodynamic models past stall are required to train pilots on stall recovery techniques using ground-based simulators, which are safe, inexpensive, and accessible. A methodology for creating representative stall models, which capture essential stall characteristics, is being developed for classes of twin-turboprop commuter and twin-engine regional jet aircraft. Despite having lower fidelity than type specific stall models generated from wind tunnel, flight test, and/or CFD studies data, these models are configuration adjustable and significantly cheaper to construct for high angle-of-attack regimes. Baseline specific stall models are modified to capture changes in aerodynamic coefficients due to configuration variations from a baseline to a target aircraft. A Shape Prescriptive Modeling approach combining existing theory and data using least-squares splines is used to make coefficient change predictions. Initial results are satisfactory and suggest that representative models are suitable for stall training.

Economic Effects of Noise Abatement Regulations on the Helicopter Industry.

DTIC Science & Technology

1982-12-01

industry is heavily subsidized through government procurement , and aircraft models are tailored to meet commercial and military applications. U.S...EFFECTS OF NOISE ABATEMENT REGULATIONS ON THE HELICOPTER INDUSTRY by Alexander Nicholson Conner December, 1982 _J LA.. Thesis Advisor: M. G. Sovereiqn...Master’s thesis; * ~ECONOMIC EFFECTS OF NOISE ABATDEMT REGULATIONS ~ *18 S. pp@gwe 000. 46060T ftuee ON THE HELICOPTER INDUSTRY -T. Amse U.CMYAY NSNK

75 FR 26885 - Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A, B, and C Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-13

... states that this ``check'' should be performed in accordance with the maintenance manual. Because we have... Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, B, and C Helicopters AGENCY: Federal... directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-76A, B, and C helicopters that requires...

Occupational Contact Dermatitis in the Canadian Aircraft Industry.

PubMed

Loranger, Camille; Moreau, Linda; Sasseville, Denis

Aircraft building exposes workers to irritant and sensitizing products. The aim of this article was to study occupational dermatoses among aircraft workers over 25 years. The files of aerospace workers referred between 1990 and 2015 were extracted from the database of the McGill University Health Centre contact dermatitis clinic. These were subdivided according to demographics, type of work, patch testing results, and final diagnosis. Of 305 workers, 58% were 40 years or younger; one third were women. Onset of dermatitis varied from 2 months to 25 years, but 120 cases (39%) occurred during the first 3 years. Fifty-one percent of the cases involved assemblers, and 27% were composite material technicians, which were overrepresented as they constitute 10% of the workforce. Of the 305 workers, 152 suffered from allergic contact dermatitis, and 96 had irritant contact dermatitis. Of those with allergic contact dermatitis, 124 reacted to epoxy-based workplace products, but only 48 had positive patch tests to commercially available epoxy allergens. More than 60% of the cases of epoxy allergy would have been missed without testing with workplace products.

A mathematical model for Vertical Attitude Takeoff and Landing (VATOL) aircraft simulation. Volume 2: Model equations and base aircraft data

NASA Technical Reports Server (NTRS)

Fortenbaugh, R. L.

1980-01-01

Equations incorporated in a VATOL six degree of freedom off-line digital simulation program and data for the Vought SF-121 VATOL aircraft concept which served as the baseline for the development of this program are presented. The equations and data are intended to facilitate the development of a piloted VATOL simulation. The equation presentation format is to state the equations which define a particular model segment. Listings of constants required to quantify the model segment, input variables required to exercise the model segment, and output variables required by other model segments are included. In several instances a series of input or output variables are followed by a section number in parentheses which identifies the model segment of origination or termination of those variables.

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.

Wind shear modeling for aircraft hazard definition

NASA Technical Reports Server (NTRS)

Frost, W.; Camp, D. W.; Wang, S. T.

1978-01-01

Mathematical models of wind profiles were developed for use in fast time and manned flight simulation studies aimed at defining and eliminating these wind shear hazards. A set of wind profiles and associated wind shear characteristics for stable and neutral boundary layers, thunderstorms, and frontal winds potentially encounterable by aircraft in the terminal area are given. Engineering models of wind shear for direct hazard analysis are presented in mathematical formulae, graphs, tables, and computer lookup routines. The wind profile data utilized to establish the models are described as to location, how obtained, time of observation and number of data points up to 500 m. Recommendations, engineering interpretations and guidelines for use of the data are given and the range of applicability of the wind shear models is described.

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.

Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/A-18 Aircraft

NASA Technical Reports Server (NTRS)

Brenner, Martin J.

1996-01-01

An F/A-18 aircraft was modified to perform flight research at high angles of attack (AOA) using thrust vectoring and advanced control law concepts for agility and performance enhancement and to provide a testbed for the computational fluid dynamics community. Aeroservoelastic (ASE) characteristics had changed considerably from the baseline F/A-18 aircraft because of structural and flight control system amendments, so analyses and flight tests were performed to verify structural stability at high AOA. Detailed actuator models that consider the physical, electrical, and mechanical elements of actuation and its installation on the airframe were employed in the analysis to accurately model the coupled dynamics of the airframe, actuators, and control surfaces. This report describes the ASE modeling procedure, ground test validation, flight test clearance, and test data analysis for the reconfigured F/A-18 aircraft. Multivariable ASE stability margins are calculated from flight data and compared to analytical margins. Because this thrust-vectoring configuration uses exhaust vanes to vector the thrust, the modeling issues are nearly identical for modem multi-axis nozzle configurations. This report correlates analysis results with flight test data and makes observations concerning the application of the linear predictions to thrust-vectoring and high-AOA flight.

Aircraft type influence on contrail properties

NASA Astrophysics Data System (ADS)

Jeßberger, P.; Voigt, C.; Schumann, U.; Sölch, I.; Schlager, H.; Kaufmann, S.; Petzold, A.; Schäuble, D.; Gayet, J.-F.

2013-12-01

The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of types A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in situ instruments on board DLR research aircraft Falcon. Within the 2 min-old contrails detected near ice saturation, we find similar effective diameters Deff (5.2-5.9 μm), but differences in particle number densities nice (162-235 cm-3) and in vertical contrail extensions (120-290 m), resulting in large differences in contrail optical depths τ at 550 nm (0.25-0.94). Hence larger aircraft produce optically thicker contrails. Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and, in addition, the Contrail and Cirrus Prediction (CoCiP) model to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ. CoCiP model results suggest that the aircraft dependence of climate-relevant contrail properties persists during contrail lifetime, adding importance to aircraft-dependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with the fuel flow rate, as confirmed by observations. For higher relative humidity with respect to ice (RHI), the analytical relationship suggests a non-linear increase in the form (RHI-12/3. Summarized, our combined results could help to more accurately assess the climate impact from aviation using an aircraft-dependent contrail parameterization.

V/STOL tilt rotor study. Volume 5: A mathematical model for real time flight simulation of the Bell model 301 tilt rotor research aircraft

NASA Technical Reports Server (NTRS)

Harendra, P. B.; Joglekar, M. J.; Gaffey, T. M.; Marr, R. L.

1973-01-01

A mathematical model for real-time flight simulation of a tilt rotor research aircraft was developed. The mathematical model was used to support the aircraft design, pilot training, and proof-of-concept aspects of the development program. The structure of the mathematical model is indicated by a block diagram. The mathematical model differs from that for a conventional fixed wing aircraft principally in the added requirement to represent the dynamics and aerodynamics of the rotors, the interaction of the rotor wake with the airframe, and the rotor control and drive systems. The constraints imposed on the mathematical model are defined.

A Comparison of Three Random Number Generators for Aircraft Dynamic Modeling Applications

NASA Technical Reports Server (NTRS)

Grauer, Jared A.

2017-01-01

Three random number generators, which produce Gaussian white noise sequences, were compared to assess their suitability in aircraft dynamic modeling applications. The first generator considered was the MATLAB (registered) implementation of the Mersenne-Twister algorithm. The second generator was a website called Random.org, which processes atmospheric noise measured using radios to create the random numbers. The third generator was based on synthesis of the Fourier series, where the random number sequences are constructed from prescribed amplitude and phase spectra. A total of 200 sequences, each having 601 random numbers, for each generator were collected and analyzed in terms of the mean, variance, normality, autocorrelation, and power spectral density. These sequences were then applied to two problems in aircraft dynamic modeling, namely estimating stability and control derivatives from simulated onboard sensor data, and simulating flight in atmospheric turbulence. In general, each random number generator had good performance and is well-suited for aircraft dynamic modeling applications. Specific strengths and weaknesses of each generator are discussed. For Monte Carlo simulation, the Fourier synthesis method is recommended because it most accurately and consistently approximated Gaussian white noise and can be implemented with reasonable computational effort.

Modeling, Simulation, and Flight Test for Automatic Flight Control of the Condor Hybrid-Electric Remote Piloted Aircraft

DTIC Science & Technology

2012-03-01

comprehensive explanations (Yechout, 2003), (Nelson, 1998). Figure 9: USAFA/Brandt Jet5 Aircraft Modeling Program 18 2.5.1 Dynamic Aircraft...16 2.5.1 Dynamic Aircraft Stability Modes .......................................................... 18 2.5.2 State...12 Figure 7: Body-Fixed Reference Frame ........................................................................... 13 Figure 8: Static and Dynamic

World commercial aircraft accidents. Second edition, 1946--1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kimura, C.Y.

1993-01-01

This report is a compilation of all accidents world-wide involving aircraft in commercial service which resulted in the loss of the airframe or one or more fatality, or both. This information has been gathered in order to present a complete inventory of commercial aircraft accidents. Events involving military action, sabotage, terrorist bombings, hijackings, suicides, and industrial ground accidents are included within this list. Included are: accidents involving world commercial jet aircraft, world commercial turboprop aircraft, world commercial pistonprop aircraft with four or more engines and world commercial pistonprop aircraft with two or three engines from 1946 to 1992. Each accidentmore » is presented with information in the following categories: date of the accident, airline and its flight numbers, type of flight, type of aircraft, aircraft registration number, construction number/manufacturers serial number, aircraft damage, accident flight phase, accident location, number of fatalities, number of occupants, cause, remarks, or description (brief) of the accident, and finally references used. The sixth chapter presents a summary of the world commercial aircraft accidents by major aircraft class (e.g. jet, turboprop, and pistonprop) and by flight phase. The seventh chapter presents several special studies including a list of world commercial aircraft accidents for all aircraft types with 100 or more fatalities in order of decreasing number of fatalities, a list of collision accidents involving commercial aircrafts, and a list of world commercial aircraft accidents for all aircraft types involving military action, sabotage, terrorist bombings, and hijackings.« less

Future aircraft networks and schedules

NASA Astrophysics Data System (ADS)

Shu, Yan

2011-07-01

Because of the importance of air transportation scheduling, the emergence of small aircraft and the vision of future fuel-efficient aircraft, this thesis has focused on the study of aircraft scheduling and network design involving multiple types of aircraft and flight services. It develops models and solution algorithms for the schedule design problem and analyzes the computational results. First, based on the current development of small aircraft and on-demand flight services, this thesis expands a business model for integrating on-demand flight services with the traditional scheduled flight services. This thesis proposes a three-step approach to the design of aircraft schedules and networks from scratch under the model. In the first step, both a frequency assignment model for scheduled flights that incorporates a passenger path choice model and a frequency assignment model for on-demand flights that incorporates a passenger mode choice model are created. In the second step, a rough fleet assignment model that determines a set of flight legs, each of which is assigned an aircraft type and a rough departure time is constructed. In the third step, a timetable model that determines an exact departure time for each flight leg is developed. Based on the models proposed in the three steps, this thesis creates schedule design instances that involve almost all the major airports and markets in the United States. The instances of the frequency assignment model created in this thesis are large-scale non-convex mixed-integer programming problems, and this dissertation develops an overall network structure and proposes iterative algorithms for solving these instances. The instances of both the rough fleet assignment model and the timetable model created in this thesis are large-scale mixed-integer programming problems, and this dissertation develops subproblem schemes for solving these instances. Based on these solution algorithms, this dissertation also presents

Integrated Mode Choice, Small Aircraft Demand, and Airport Operations Model User's Guide

NASA Technical Reports Server (NTRS)

Yackovetsky, Robert E. (Technical Monitor); Dollyhigh, Samuel M.

2004-01-01

A mode choice model that generates on-demand air travel forecasts at a set of GA airports based on changes in economic characteristics, vehicle performance characteristics such as speed and cost, and demographic trends has been integrated with a model to generate itinerate aircraft operations by airplane category at a set of 3227 airports. Numerous intermediate outputs can be generated, such as the number of additional trips diverted from automobiles and schedule air by the improved performance and cost of on-demand air vehicles. The total number of transported passenger miles that are diverted is also available. From these results the number of new aircraft to service the increased demand can be calculated. Output from the models discussed is in the format to generate the origin and destination traffic flow between the 3227 airports based on solutions to a gravity model.

Research on motion model for the hypersonic boost-glide aircraft

NASA Astrophysics Data System (ADS)

Xu, Shenda; Wu, Jing; Wang, Xueying

2015-11-01

A motion model for the hypersonic boost-glide aircraft(HBG) was proposed in this paper, which also analyzed the precision of model through simulation. Firstly the trajectory of HBG was analyzed, and a scheme which divide the trajectory into two parts then build the motion model on each part. Secondly a restrained model of boosting stage and a restrained model of J2 perturbation were established, and set up the observe model. Finally the analysis of simulation results show the feasible and high-accuracy of the model, and raise a expectation for intensive research.

Modeling Flight Attendants’ Exposures to Pesticide in Disinsected Aircraft Cabins

PubMed Central

Zhang, Yong; Isukapalli, Sastry; Georgopoulos, Panos; Weisel, Clifford

2014-01-01

Aircraft cabin disinsection is required by some countries to kill insects that may pose risks to public health and native ecological systems. A probabilistic model has been developed by considering the microenvironmental dynamics of the pesticide in conjunction with the activity patterns of flight attendants, to assess their exposures and risks to pesticide in disinsected aircraft cabins under three scenarios of pesticide application. Main processes considered in the model are microenvironmental transport and deposition, volatilization, and transfer of pesticide when passengers and flight attendants come in contact with the cabin surfaces. The simulated pesticide airborne mass concentration and surface mass loadings captured measured ranges reported in the literature. The medians (means±standard devitions) of daily total exposures intakes were 0.24 (3.8±10.0), 1.4 (4.2±5.7) and 0.15 (2.1±3.2) μg/(day kg BW) for scenarios of Residual Application, Preflight and Top-of-Descent spraying, respectively. Exposure estimates were sensitive to parameters corresponding to pesticide deposition, body surface area and weight, surface-to-body transfer efficiencies, and efficiency of adherence to skin. Preflight spray posed 2.0 and 3.1 times higher pesticide exposure risk levels for flight attendants in disinsected aircraft cabins than Top-of-Descent spray and Residual Application, respectively. PMID:24251734

Concurrent airline fleet allocation and aircraft design with profit modeling for multiple airlines

NASA Astrophysics Data System (ADS)

Govindaraju, Parithi

A "System of Systems" (SoS) approach is particularly beneficial in analyzing complex large scale systems comprised of numerous independent systems -- each capable of independent operations in their own right -- that when brought in conjunction offer capabilities and performance beyond the constituents of the individual systems. The variable resource allocation problem is a type of SoS problem, which includes the allocation of "yet-to-be-designed" systems in addition to existing resources and systems. The methodology presented here expands upon earlier work that demonstrated a decomposition approach that sought to simultaneously design a new aircraft and allocate this new aircraft along with existing aircraft in an effort to meet passenger demand at minimum fleet level operating cost for a single airline. The result of this describes important characteristics of the new aircraft. The ticket price model developed and implemented here enables analysis of the system using profit maximization studies instead of cost minimization. A multiobjective problem formulation has been implemented to determine characteristics of a new aircraft that maximizes the profit of multiple airlines to recognize the fact that aircraft manufacturers sell their aircraft to multiple customers and seldom design aircraft customized to a single airline's operations. The route network characteristics of two simple airlines serve as the example problem for the initial studies. The resulting problem formulation is a mixed-integer nonlinear programming problem, which is typically difficult to solve. A sequential decomposition strategy is applied as a solution methodology by segregating the allocation (integer programming) and aircraft design (non-linear programming) subspaces. After solving a simple problem considering two airlines, the decomposition approach is then applied to two larger airline route networks representing actual airline operations in the year 2005. The decomposition strategy serves

Analysing of critical force effects of aircraft seat belt using truss elements

NASA Astrophysics Data System (ADS)

Klemenc, Marek; Markopoulos, Alexandros; Maršálek, Pavel

2017-07-01

This paper deals with the mathematical modelling of an aircraft seat belt crash test. The main goal is determination of a time course of the reactions in a lap belt anchoring points and their maximum values. This work was created on the basis of practical requirements from industry. Results are going to be reflected in developing a new type of aircraft seats. We mainly focus on the mathematical modelling of dynamic problems using the finite element method (FEM). Derived procedures are implemented in the Python programming language and are verified by several examples. A final calculation algorithm is applied on the analysis of the safety belt. We consider that a seat belt bending stiffness is very small compared to a tensile stiffness, therefore we used a 2D plane truss element.

A review of advanced turboprop transport aircraft

NASA Astrophysics Data System (ADS)

Lange, Roy H.

The application of advanced technologies shows the potential for significant improvement in the fuel efficiency and operating costs of future transport aircraft envisioned for operation in the 1990s time period. One of the more promising advanced technologies is embodied in an advanced turboprop concept originated by Hamilton Standard and NASA and known as the propfan. The propfan concept features a highly loaded multibladed, variable pitch propeller geared to a high pressure ratio gas turbine engine. The blades have high sweepback and advanced airfoil sections to achieve 80 percent propulsive efficiency at M=0.80 cruise speed. Aircraft system studies have shown improvements in fuel efficiency of 15-20 percent for propfan advanced transport aircraft as compared to equivalent turbofan transports. Beginning with the Lockheed C-130 and Electra turboprop aircraft, this paper presents an overview of the evolution of propfan aircraft design concepts and system studies. These system studies include possible civil and military transport applications and data on the performance, community and far-field noise characteristics and operating costs of propfan aircraft design concepts. NASA Aircraft Energy Efficiency (ACEE) program propfan projects with industry are reviewed with respect to system studies of propfan aircraft and recommended flight development programs.

Aeroelastic Modeling of Elastically Shaped Aircraft Concept via Wing Shaping Control for Drag Reduction

NASA Technical Reports Server (NTRS)

Nguyen, Nhan; James Urnes, Sr.

2012-01-01

Lightweight aircraft design has received a considerable attention in recent years as a means for improving cruise efficiency. Reducing aircraft weight results in lower lift requirements which directly translate into lower drag, hence reduced engine thrust requirements during cruise. The use of lightweight materials such as advanced composite materials has been adopted by airframe manufacturers in current and future aircraft. Modern lightweight materials can provide less structural rigidity while maintaining load-carrying capacity. As structural flexibility increases, aeroelastic interactions with aerodynamic forces and moments become an increasingly important consideration in aircraft design and aerodynamic performance. Furthermore, aeroelastic interactions with flight dynamics can result in issues with vehicle stability and control. Abstract This paper describes a recent aeroelastic modeling effort for an elastically shaped aircraft concept (ESAC). The aircraft model is based on the rigid-body generic transport model (GTM) originally developed at NASA Langley Research Center. The ESAC distinguishes itself from the GTM in that it is equipped with highly flexible wing structures as a weight reduction design feature. More significantly, the wings are outfitted with a novel control effector concept called variable camber continuous trailing edge (VCCTE) flap system for active control of wing aeroelastic deflections to optimize the local angle of attack of wing sections for improved aerodynamic efficiency through cruise drag reduction and lift enhancement during take-off and landing. The VCCTE flap is a multi-functional and aerodynamically efficient device capable of achieving high lift-to-drag ratios. The flap system is comprised of three chordwise segments that form the variable camber feature of the flap and multiple spanwise segments that form a piecewise continuous trailing edge. By configuring the flap camber and trailing edge shape, drag reduction could be

Aircraft type influence on contrail properties

NASA Astrophysics Data System (ADS)

Jeßberger, P.; Voigt, C.; Schumann, U.; Sölch, I.; Schlager, H.; Kaufmann, S.; Petzold, A.; Schäuble, D.; Gayet, J.-F.

2013-05-01

The investigation of the impact of aircraft parameters on contrail properties helps to better understand the climate impact from aviation. Yet, in observations, it is a challenge to separate aircraft and meteorological influences on contrail formation. During the CONCERT campaign in November 2008, contrails from 3 Airbus passenger aircraft of type A319-111, A340-311 and A380-841 were probed at cruise under similar meteorological conditions with in-situ instruments on board the DLR research aircraft Falcon. Within the 2 min old contrails detected near ice saturation, we find similar effective diameters Deff (5.2-5.9 μm), but differences in particle number densities nice (162-235 cm-3) and in vertical contrail extensions (120-290 m), resulting in large differences in contrail optical depths τ (0.25-0.94). Hence larger aircraft produce optically thicker contrails. Based on the observations, we apply the EULAG-LCM model with explicit ice microphysics and in addition the Contrail and Cirrus Prediction model CoCiP to calculate the aircraft type impact on young contrails under identical meteorological conditions. The observed increase in τ for heavier aircraft is confirmed by the models, yet for generally smaller τ. An aircraft dependence of climate relevant contrail properties persists during contrail lifetime, adding importance to aircraft dependent model initialization. We finally derive an analytical relationship between contrail, aircraft and meteorological parameters. Near ice saturation, contrail width × τ scales linearly with fuel flow rate as confirmed by observations. For higher saturation ratios approximations from theory suggest a non-linear increase in the form (RHI-1)2/3. Summarized our combined results could help to more accurately assess the climate impact from aviation using an aircraft dependent contrail parameterization.

Models and techniques for evaluating the effectiveness of aircraft computing systems

NASA Technical Reports Server (NTRS)

Meyer, J. F.

1978-01-01

Progress in the development of system models and techniques for the formulation and evaluation of aircraft computer system effectiveness is reported. Topics covered include: analysis of functional dependence: a prototype software package, METAPHOR, developed to aid the evaluation of performability; and a comprehensive performability modeling and evaluation exercise involving the SIFT computer.

Lateral-Directional Parameter Estimation on the X-48B Aircraft Using an Abstracted, Multi-Objective Effector Model

NASA Technical Reports Server (NTRS)

Ratnayake, Nalin A.; Waggoner, Erin R.; Taylor, Brian R.

2011-01-01

The problem of parameter estimation on hybrid-wing-body aircraft is complicated by the fact that many design candidates for such aircraft involve a large number of aerodynamic control effectors that act in coplanar motion. This adds to the complexity already present in the parameter estimation problem for any aircraft with a closed-loop control system. Decorrelation of flight and simulation data must be performed in order to ascertain individual surface derivatives with any sort of mathematical confidence. Non-standard control surface configurations, such as clamshell surfaces and drag-rudder modes, further complicate the modeling task. In this paper, time-decorrelation techniques are applied to a model structure selected through stepwise regression for simulated and flight-generated lateral-directional parameter estimation data. A virtual effector model that uses mathematical abstractions to describe the multi-axis effects of clamshell surfaces is developed and applied. Comparisons are made between time history reconstructions and observed data in order to assess the accuracy of the regression model. The Cram r-Rao lower bounds of the estimated parameters are used to assess the uncertainty of the regression model relative to alternative models. Stepwise regression was found to be a useful technique for lateral-directional model design for hybrid-wing-body aircraft, as suggested by available flight data. Based on the results of this study, linear regression parameter estimation methods using abstracted effectors are expected to perform well for hybrid-wing-body aircraft properly equipped for the task.

Current Methods Modeling and Simulating Icing Effects on Aircraft Performance, Stability, Control

NASA Technical Reports Server (NTRS)

Ratvasky, Thomas P.; Barnhart, Billy P.; Lee, Sam

2010-01-01

Icing alters the shape and surface characteristics of aircraft components, which results in altered aerodynamic forces and moments caused by air flow over those iced components. The typical effects of icing are increased drag, reduced stall angle of attack, and reduced maximum lift. In addition to the performance changes, icing can also affect control surface effectiveness, hinge moments, and damping. These effects result in altered aircraft stability and control and flying qualities. Over the past 80 years, methods have been developed to understand how icing affects performance, stability, and control. Emphasis has been on wind-tunnel testing of two-dimensional subscale airfoils with various ice shapes to understand their effect on the flowfield and ultimately the aerodynamics. This research has led to wind-tunnel testing of subscale complete aircraft models to identify the integrated effects of icing on the aircraft system in terms of performance, stability, and control. Data sets of this nature enable pilot-in-the-loop simulations to be performed for pilot training or engineering evaluation of system failure impacts or control system design.

Vehicle Sketch Pad: a Parametric Geometry Modeler for Conceptual Aircraft Design

NASA Technical Reports Server (NTRS)

Hahn, Andrew S.

2010-01-01

The conceptual aircraft designer is faced with a dilemma, how to strike the best balance between productivity and fidelity? Historically, handbook methods have required only the coarsest of geometric parameterizations in order to perform analysis. Increasingly, there has been a drive to upgrade analysis methods, but these require considerably more precise and detailed geometry. Attempts have been made to use computer-aided design packages to fill this void, but their cost and steep learning curve have made them unwieldy at best. Vehicle Sketch Pad (VSP) has been developed over several years to better fill this void. While no substitute for the full feature set of computer-aided design packages, VSP allows even novices to quickly become proficient in defining three-dimensional, watertight aircraft geometries that are adequate for producing multi-disciplinary meta-models for higher order analysis methods, wind tunnel and display models, as well as a starting point for animation models. This paper will give an overview of the development and future course of VSP.

Low Speed Wind Tunnel Tests on a One-Seventh Scale Model of the H.126 Jet Flap Aircraft

NASA Technical Reports Server (NTRS)

Laub, G. H.

1975-01-01

Low speed wind tunnel tests were performed on a one-seventh scale model of the British H.126 jet flap research aircraft over a range of jet momentum coefficients. The primary objective was to compare model aerodynamic characteristics with those of the aircraft, with the intent to provide preliminary data needed towards establishing small-to-full scale correlating techniques on jet flap V/STOL aircraft configurations. Lift and drag coefficients from the model and aircraft tests were found to be in reasonable agreement. The pitching moment coefficient and trim condition correlation was poor. A secondary objective was to evaluate a modified thrust nozzle having thrust reversal capability. The results showed there was a considerable loss of lift in the reverse thrust operational mode because of increased nozzle-wing flow interference. A comparison between the model simulated H.126 wing jet efflux and the model uniform pressure distribution wing jet efflux indicated no more than 5% loss in weight flow rate.

Aircraft Design Software

NASA Technical Reports Server (NTRS)

1997-01-01

Successful commercialization of the AirCraft SYNThesis (ACSYNT) tool has resulted in the creation of Phoenix Integration, Inc. ACSYNT has been exclusively licensed to the company, an outcome of a seven year, $3 million effort to provide unique software technology to a focused design engineering market. Ames Research Center formulated ACSYNT and in working with the Virginia Polytechnic Institute CAD Laboratory, began to design and code a computer-aided design for ACSYNT. Using a Joint Sponsored Research Agreement, Ames formed an industry-government-university alliance to improve and foster research and development for the software. As a result of the ACSYNT Institute, the software is becoming a predominant tool for aircraft conceptual design. ACSYNT has been successfully applied to high- speed civil transport configuration, subsonic transports, and supersonic fighters.

Light aircraft sound transmission studies - Noise reduction model

NASA Technical Reports Server (NTRS)

Atwal, Mahabir S.; Heitman, Karen E.; Crocker, Malcolm J.

1987-01-01

Experimental tests conducted on the fuselage of a single-engine Piper Cherokee light aircraft suggest that the cabin interior noise can be reduced by increasing the transmission loss of the dominant sound transmission paths and/or by increasing the cabin interior sound absorption. The validity of using a simple room equation model to predict the cabin interior sound-pressure level for different fuselage and exterior sound field conditions is also presented. The room equation model is based on the sound power flow balance for the cabin space and utilizes the measured transmitted sound intensity data. The room equation model predictions were considered good enough to be used for preliminary acoustical design studies.

Nitrous oxide pollution from aircraft to increase by 2050

NASA Astrophysics Data System (ADS)

Bhattacharya, Atreyee

2012-09-01

The transportation industry is not only one of the biggest sources of air pollution and a significant player in greenhouse gas-induced global warming, but, as a new study shows, the industry could also be responsible for episodes of ozone (O3 ) pollution, particularly over the United States and northern Europe. Combustion of fuel in cars, shipping vessels, and low-flying aircraft produce nitrogen oxides (NOx), which not only decrease the lifetime of greenhouse gases such as methane but also react with other molecules in the atmosphere to form tropospheric O3, another, more lethal, air pollutant. Hauglustaine and Koff used a global three-dimensional chemistry-climate model to investigate how different components of the transportation industry—cars, ships, and low-flying aircraft—would contribute to NOx pollution over the next few decades under several projected emission scenarios. They found that as road transportation stagnates or even declines due to stricter regulations and congestion, NOx emissions from cars will decrease over time. However, aircraft will increase in number and could contribute between 25% and 48% of NOx emissions, which will be most severe over the United States and Europe—two regions with the highest growth rate in commercial aviation.

Developing an Accurate CFD Based Gust Model for the Truss Braced Wing Aircraft

NASA Technical Reports Server (NTRS)

Bartels, Robert E.

2013-01-01

The increased flexibility of long endurance aircraft having high aspect ratio wings necessitates attention to gust response and perhaps the incorporation of gust load alleviation. The design of civil transport aircraft with a strut or truss-braced high aspect ratio wing furthermore requires gust response analysis in the transonic cruise range. This requirement motivates the use of high fidelity nonlinear computational fluid dynamics (CFD) for gust response analysis. This paper presents the development of a CFD based gust model for the truss braced wing aircraft. A sharp-edged gust provides the gust system identification. The result of the system identification is several thousand time steps of instantaneous pressure coefficients over the entire vehicle. This data is filtered and downsampled to provide the snapshot data set from which a reduced order model is developed. A stochastic singular value decomposition algorithm is used to obtain a proper orthogonal decomposition (POD). The POD model is combined with a convolution integral to predict the time varying pressure coefficient distribution due to a novel gust profile. Finally the unsteady surface pressure response of the truss braced wing vehicle to a one-minus-cosine gust, simulated using the reduced order model, is compared with the full CFD.

Aviation industry overview, fiscal year 1998

DOT National Transportation Integrated Search

1999-02-01

The contents of this research report are listed as follows: Industry overview; U.S. economic outlook; Passenger enplanements and aircraft departures; Traffic and seat capacity; Financial results; Air carrier aircraft orders and deliveries; General av...

Preliminary design of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter aircraft

NASA Technical Reports Server (NTRS)

Cox, Brian; Borchers, Paul; Gomer, Charlie; Henderson, Dean; Jacobs, Tavis; Lawson, Todd; Peterson, Eric; Ross, Tweed, III; Bellmard, Larry

1990-01-01

The preliminary design study of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter is presented. A brief historical survey of powered lift vehicles was presented, followed by a technology assessment of the latest supersonic STOVL engine cycles under consideration by industry and government in the U.S. and UK. A survey of operational fighter/attack aircraft and the modern battlefield scenario were completed to develop, respectively, the performance requirements and mission profiles for the study. Three configurations were initially investigated with the following engine cycles: a hybrid fan vectored thrust cycle, a lift+lift/cruise cycle, and a mixed flow vectored thrust cycle. The lift+lift/cruise aircraft configuration was selected for detailed design work which consisted of: (1) a material selection and structural layout, including engine removal considerations, (2) an aircraft systems layout, (3) a weapons integration model showing the internal weapons bay mechanism, (4) inlet and nozzle integration, (5) an aircraft suckdown prediction, (6) an aircraft stability and control analysis, including a takeoff, hover, and transition control analysis, (7) a performance and mission capability study, and (8) a life cycle cost analysis. A supersonic fighter aircraft with STOVL capability with the lift+lift/cruise engine cycle seems a viable option for the next generation fighter.

Models and techniques for evaluating the effectiveness of aircraft computing systems

NASA Technical Reports Server (NTRS)

Meyer, J. F.

1977-01-01

Models, measures and techniques were developed for evaluating the effectiveness of aircraft computing systems. The concept of effectiveness involves aspects of system performance, reliability and worth. Specifically done was a detailed development of model hierarchy at mission, functional task, and computational task levels. An appropriate class of stochastic models was investigated which served as bottom level models in the hierarchial scheme. A unified measure of effectiveness called 'performability' was defined and formulated.

The ASAC Air Carrier Investment Model (Second Generation)

NASA Technical Reports Server (NTRS)

Wingrove, Earl R., III; Johnson, Jesse P.; Sickles, Robin C.; Good, David H.

1997-01-01

To meet its objective of assisting the U.S. aviation industry with the technological challenges of the future, NASA must identify research areas that have the greatest potential for improving the operation of the air transportation system. To accomplish this, NASA is building an Aviation System Analysis Capability (ASAC). The ASAC differs from previous NASA modeling efforts in that the economic behavior of buyers and sellers in the air transportation and aviation industries is central to its conception. To link the economics of flight with the technology of flight, ASAC requires a parametrically based mode with extensions that link airline operations and investments in aircraft with aircraft characteristics. This model also must provide a mechanism for incorporating air travel demand and profitability factors into the airlines' investment decisions. Finally, the model must be flexible and capable of being incorporated into a wide-ranging suite of economic and technical models that are envisioned for ASAC. We describe a second-generation Air Carrier Investment Model that meets these requirements. The enhanced model incorporates econometric results from the supply and demand curves faced by U.S.-scheduled passenger air carriers. It uses detailed information about their fleets in 1995 to make predictions about future aircraft purchases. It enables analysts with the ability to project revenue passenger-miles flown, airline industry employment, airline operating profit margins, numbers and types of aircraft in the fleet, and changes in aircraft manufacturing employment under various user-defined scenarios.

Flight control optimization from design to assessment application on the Cessna Citation X business aircraft =

NASA Astrophysics Data System (ADS)

Boughari, Yamina

New methodologies have been developed to optimize the integration, testing and certification of flight control systems, an expensive process in the aerospace industry. This thesis investigates the stability of the Cessna Citation X aircraft without control, and then optimizes two different flight controllers from design to validation. The aircraft's model was obtained from the data provided by the Research Aircraft Flight Simulator (RAFS) of the Cessna Citation business aircraft. To increase the stability and control of aircraft systems, optimizations of two different flight control designs were performed: 1) the Linear Quadratic Regulation and the Proportional Integral controllers were optimized using the Differential Evolution algorithm and the level 1 handling qualities as the objective function. The results were validated for the linear and nonlinear aircraft models, and some of the clearance criteria were investigated; and 2) the Hinfinity control method was applied on the stability and control augmentation systems. To minimize the time required for flight control design and its validation, an optimization of the controllers design was performed using the Differential Evolution (DE), and the Genetic algorithms (GA). The DE algorithm proved to be more efficient than the GA. New tools for visualization of the linear validation process were also developed to reduce the time required for the flight controller assessment. Matlab software was used to validate the different optimization algorithms' results. Research platforms of the aircraft's linear and nonlinear models were developed, and compared with the results of flight tests performed on the Research Aircraft Flight Simulator. Some of the clearance criteria of the optimized H-infinity flight controller were evaluated, including its linear stability, eigenvalues, and handling qualities criteria. Nonlinear simulations of the maneuvers criteria were also investigated during this research to assess the Cessna

Numeric Design and Performance Analysis of Solid Oxide Fuel Cell -- Gas Turbine Hybrids on Aircraft

NASA Astrophysics Data System (ADS)

Hovakimyan, Gevorg

The aircraft industry benefits greatly from small improvements in aircraft component design. One possible area of improvement is in the Auxiliary Power Unit (APU). Modern aircraft APUs are gas turbines located in the tail section of the aircraft that generate additional power when needed. Unfortunately the efficiency of modern aircraft APUs is low. Solid Oxide Fuel Cell/Gas Turbine (SOFC/GT) hybrids are one possible alternative for replacing modern gas turbine APUs. This thesis investigates the feasibility of replacing conventional gas turbine APUs with SOFC/GT APUs on aircraft. An SOFC/GT design algorithm was created in order to determine the specifications of an SOFC/GT APU. The design algorithm is comprised of several integrated modules which together model the characteristics of each component of the SOFC/GT system. Given certain overall inputs, through numerical analysis, the algorithm produces an SOFC/GT APU, optimized for specific power and efficiency, capable of performing to the required specifications. The SOFC/GT design is then input into a previously developed quasi-dynamic SOFC/GT model to determine its load following capabilities over an aircraft flight cycle. Finally an aircraft range study is conducted to determine the feasibility of the SOFC/GT APU as a replacement for the conventional gas turbine APU. The design results show that SOFC/GT APUs have lower specific power than GT systems, but have much higher efficiencies. Moreover, the dynamic simulation results show that SOFC/GT APUs are capable of following modern flight loads. Finally, the range study determined that SOFC/GT APUs are more attractive over conventional APUs for longer range aircraft.

Roll plane analysis of on-aircraft antennas

NASA Technical Reports Server (NTRS)

Burnside, W. D.; Marhefka, R. J.; Byu, C. L.

1974-01-01

Roll plane radiation patterns of on-aircraft antennas are analyzed using high frequency solutions. Aircraft-antenna pattern performance in which the aircraft is modelled in its most basic form is presented. The fuselage is assumed to be a perfectly conducting elliptic cylinder with the antennas mounted near the top or bottom. The wings are simulated by arbitrarily many sided flat plates and the engines by circular cylinders. The patterns in each case are verified by measured results taken on simple models as well as scale models of actual aircraft.

Theoretical vibro-acoustic modeling of acoustic noise transmission through aircraft windows

NASA Astrophysics Data System (ADS)

Aloufi, Badr; Behdinan, Kamran; Zu, Jean

2016-06-01

In this paper, a fully vibro-acoustic model for sound transmission across a multi-pane aircraft window is developed. The proposed model is efficiently applied for a set of window models to perform extensive theoretical parametric studies. The studied window configurations generally simulate the passenger window designs of modern aircraft classes which have an exterior multi-Plexiglas pane, an interior single acrylic glass pane and a dimmable glass ("smart" glass), all separated by thin air cavities. The sound transmission loss (STL) characteristics of three different models, triple-, quadruple- and quintuple-paned windows identical in size and surface density, are analyzed for improving the acoustic insulation performances. Typical results describing the influence of several system parameters, such as the thicknesses, number and spacing of the window panes, on the transmission loss are then investigated. In addition, a comparison study is carried out to evaluate the acoustic reduction capability of each window model. The STL results show that the higher frequencies sound transmission loss performance can be improved by increasing the number of window panels, however, the low frequency performance is decreased, particularly at the mass-spring resonances.

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.

Predicting Visibility of Aircraft

PubMed Central

Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

2009-01-01

Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

Detection flying aircraft from Landsat 8 OLI data

NASA Astrophysics Data System (ADS)

Zhao, F.; Xia, L.; Kylling, A.; Li, R. Q.; Shang, H.; Xu, Ming

2018-07-01

Monitoring flying aircraft from satellite data is important for evaluating the climate impact caused by the global aviation industry. However, due to the small size of aircraft and the complex surface types, it is almost impossible to identify aircraft from satellite data with moderate resolution, e.g. 30 m. In this study, the 1.38 μm water vapor absorption channel, often used for cirrus cloud or ash detection, is for the first time used to monitor flying aircraft from Landsat 8 data. The basic theory behind the detection of flying aircraft is that in the 1.38 μm channel most of the background reflectance between the ground and the aircraft is masked due to the strong water vapor absorption, while the signal of the flying aircraft will be attenuated less due to the low water vapor content between the satellite and the aircraft. A new composition of the Laplacian and Sobel operators for segmenting aircraft and other features were used to identify the flying aircraft. The Landsat 8 Operational Land Imager (OLI) 2.1 μm channel was used to make the method succeed under low vapor content. The accuracy assessment based on 65 Landsat 8 images indicated that the percentage of leakage is 3.18% and the percentage of false alarm is 0.532%.

Trajectory Control for Very Flexible Aircraft

DTIC Science & Technology

2006-10-30

aircraft are coupled with the aeroelastic equations that govern the geometrically nonlinear structural response of the vehicle. A low -order strain...nonlinear structural formulation, the finite state aerodynamic model, and the nonlinear rigid body equations together provide a low -order complete...nonlinear aircraft analysis tool. Due to the inherent flexibility of the aircraft modeling, the low order structural fre- quencies are of the same order

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.

Computational models for the viscous/inviscid analysis of jet aircraft exhaust plumes

NASA Astrophysics Data System (ADS)

Dash, S. M.; Pergament, H. S.; Thorpe, R. D.

1980-05-01

Computational models which analyze viscous/inviscid flow processes in jet aircraft exhaust plumes are discussed. These models are component parts of an NASA-LaRC method for the prediction of nozzle afterbody drag. Inviscid/shock processes are analyzed by the SCIPAC code which is a compact version of a generalized shock capturing, inviscid plume code (SCIPPY). The SCIPAC code analyzes underexpanded jet exhaust gas mixtures with a self-contained thermodynamic package for hydrocarbon exhaust products and air. A detailed and automated treatment of the embedded subsonic zones behind Mach discs is provided in this analysis. Mixing processes along the plume interface are analyzed by two upgraded versions of an overlaid, turbulent mixing code (BOAT) developed previously for calculating nearfield jet entrainment. The BOATAC program is a frozen chemistry version of BOAT containing the aircraft thermodynamic package as SCIPAC; BOATAB is an afterburning version with a self-contained aircraft (hydrocarbon/air) finite-rate chemistry package. The coupling of viscous and inviscid flow processes is achieved by an overlaid procedure with interactive effects accounted for by a displacement thickness type correction to the inviscid plume interface.

Model experiments to evaluate vortex dissipation devices proposed for installation on or near aircraft runways

NASA Technical Reports Server (NTRS)

Kohl, R. E.

1973-01-01

The effectiveness of various vortex dissipation devices proposed for installation on or near aircraft runways is evaluated on basis of results of experiments conducted with a 0.03-scale model of a Boeing 747 transport aircraft in conjunction with a simulated runway. The test variables included type of vortex dissipation device, mode of operation of the powered devices, and altitude, lift coefficient and speed of the generating aircraft. A total of fifteen devices was investigated. The evaluation is based on time sequence photographs taken in the vertical and horizontal planes during each run.

Update of Aircraft Profile Data for the Integrated Noise Model Computer Program. Volume 2. Appendix A: Aircraft Takeoff and Landing Profiles

DTIC Science & Technology

1992-03-01

8 KT) 02- 10 -1992 09: 48 :32 AIRCRAFT ID AIRCRAFT AND ENGINE AIRCRAFT NUMBER NAMES CATEGORY ------------------- ------------------- -------- 003...MAX CLIMB 8 CLIMB ZErO MAX CLIMB 9 CLIMB ZERO MAX CLIMB A-21 TAKEOFF PROFILE DATA (HEADWIND = 8 KT) 02- 10 -1992 09: 48 :36 AIRCRAFT AIRCRAFT AND ENGINE...CLIMB ZERO USR SUPPL 34033 LB 10 CLIMB ZERO USR SUPPL 34798 LB A-194 TAKEOFF PROFILE DATA (HEADWIND = 8 KT) 06-24-1991 10 :33: 48 AIRCRAFT AIRCRAFT

NASA Dryden's Dave Bushman aims the optics of a laser device at a panel on a model aircraft during the first flight demonstration of an aircraft powered by laser light.

NASA Image and Video Library

2003-09-17

NASA Dryden project engineer Dave Bushman carefully aims the optics of a laser device at a solar cell panel on a model aircraft during the first flight demonstration of an aircraft powered by laser light.

Application of Metaheuristic and Deterministic Algorithms for Aircraft Reference Trajectory Optimization =

NASA Astrophysics Data System (ADS)

Murrieta Mendoza, Alejandro

Aircraft reference trajectory is an alternative method to reduce fuel consumption, thus the pollution released to the atmosphere. Fuel consumption reduction is of special importance for two reasons: first, because the aeronautical industry is responsible of 2% of the CO2 released to the atmosphere, and second, because it will reduce the flight cost. The aircraft fuel model was obtained from a numerical performance database which was created and validated by our industrial partner from flight experimental test data. A new methodology using the numerical database was proposed in this thesis to compute the fuel burn for a given trajectory. Weather parameters such as wind and temperature were taken into account as they have an important effect in fuel burn. The open source model used to obtain the weather forecast was provided by Weather Canada. A combination of linear and bi-linear interpolations allowed finding the required weather data. The search space was modelled using different graphs: one graph was used for mapping the different flight phases such as climb, cruise and descent, and another graph was used for mapping the physical space in which the aircraft would perform its flight. The trajectory was optimized in its vertical reference trajectory using the Beam Search algorithm, and a combination of the Beam Search algorithm with a search space reduction technique. The trajectory was optimized simultaneously for the vertical and lateral reference navigation plans while fulfilling a Required Time of Arrival constraint using three different metaheuristic algorithms: the artificial bee's colony, and the ant colony optimization. Results were validated using the software FlightSIMRTM, a commercial Flight Management System, an exhaustive search algorithm, and as flown flights obtained from flightawareRTM. All algorithms were able to reduce the fuel burn, and the flight costs. None None None None None None None

Bayesian-MCMC-based parameter estimation of stealth aircraft RCS models

NASA Astrophysics Data System (ADS)

Xia, Wei; Dai, Xiao-Xia; Feng, Yuan

2015-12-01

When modeling a stealth aircraft with low RCS (Radar Cross Section), conventional parameter estimation methods may cause a deviation from the actual distribution, owing to the fact that the characteristic parameters are estimated via directly calculating the statistics of RCS. The Bayesian-Markov Chain Monte Carlo (Bayesian-MCMC) method is introduced herein to estimate the parameters so as to improve the fitting accuracies of fluctuation models. The parameter estimations of the lognormal and the Legendre polynomial models are reformulated in the Bayesian framework. The MCMC algorithm is then adopted to calculate the parameter estimates. Numerical results show that the distribution curves obtained by the proposed method exhibit improved consistence with the actual ones, compared with those fitted by the conventional method. The fitting accuracy could be improved by no less than 25% for both fluctuation models, which implies that the Bayesian-MCMC method might be a good candidate among the optimal parameter estimation methods for stealth aircraft RCS models. Project supported by the National Natural Science Foundation of China (Grant No. 61101173), the National Basic Research Program of China (Grant No. 613206), the National High Technology Research and Development Program of China (Grant No. 2012AA01A308), the State Scholarship Fund by the China Scholarship Council (CSC), and the Oversea Academic Training Funds, and University of Electronic Science and Technology of China (UESTC).

Issues related to aircraft take-off plumes in a mesoscale photochemical model.

PubMed

Bossioli, Elissavet; Tombrou, Maria; Helmis, Costas; Kurtenbach, Ralf; Wiesen, Peter; Schäfer, Klaus; Dandou, Aggeliki; Varotsos, Kostas V

2013-07-01

The physical and chemical characteristics of aircraft plumes at the take-off phase are simulated with the mesoscale CAMx model using the individual plume segment approach, in a highly resolved domain, covering the Athens International Airport. Emission indices during take-off measured at the Athens International Airport are incorporated. Model predictions are compared with in situ point and path-averaged observations (NO, NO₂) downwind of the runway at the ground. The influence of modeling process, dispersion properties and background air composition on the chemical evolution of the aircraft plumes is examined. It is proven that the mixing properties mainly determine the plume dispersion. The initial plume properties become significant for the selection of the appropriate vertical resolution. Besides these factors, the background NOx and O₃ concentration levels control NOx distribution and their conversion to nitrogen reservoir species. Copyright © 2013 Elsevier B.V. All rights reserved.

Model Order Reduction of Aeroservoelastic Model of Flexible Aircraft

NASA Technical Reports Server (NTRS)

Wang, Yi; Song, Hongjun; Pant, Kapil; Brenner, Martin J.; Suh, Peter

2016-01-01

This paper presents a holistic model order reduction (MOR) methodology and framework that integrates key technological elements of sequential model reduction, consistent model representation, and model interpolation for constructing high-quality linear parameter-varying (LPV) aeroservoelastic (ASE) reduced order models (ROMs) of flexible aircraft. The sequential MOR encapsulates a suite of reduction techniques, such as truncation and residualization, modal reduction, and balanced realization and truncation to achieve optimal ROMs at grid points across the flight envelope. The consistence in state representation among local ROMs is obtained by the novel method of common subspace reprojection. Model interpolation is then exploited to stitch ROMs at grid points to build a global LPV ASE ROM feasible to arbitrary flight condition. The MOR method is applied to the X-56A MUTT vehicle with flexible wing being tested at NASA/AFRC for flutter suppression and gust load alleviation. Our studies demonstrated that relative to the fullorder model, our X-56A ROM can accurately and reliably capture vehicles dynamics at various flight conditions in the target frequency regime while the number of states in ROM can be reduced by 10X (from 180 to 19), and hence, holds great promise for robust ASE controller synthesis and novel vehicle design.

Dynamics of the aircraft in a vortex wake

NASA Astrophysics Data System (ADS)

Gaifullin, A. M.; Sviridenko, Yu N.

2018-03-01

This paper considers the aerodynamics and the dynamics of an aircraft on various modes when the aircraft enters a strongly swirling flow. This is the case when an aircraft purposefully enters the jet-vortex wake of another aircraft in the course of in-flight refuelling, when an aircraft is flying in the trail of an aircraft carrier during landing, or when an aircraft accidentally enters other aircrafts’ vortex wakes. These situations, according to pilots’ evaluation, are the most dangerous and the most difficult modes for piloting. That is why their real time modelling on flight simulators has taken on particular importance. This article provides the algorithms and methodology of mathematical modelling of aerodynamic forces and moments which act upon an aircraft in vortex wakes.

A non-gaussian model of continuous atmospheric turbulence for use in aircraft design

NASA Technical Reports Server (NTRS)

Reeves, P. M.; Joppa, R. G.; Ganzer, V. M.

1976-01-01

A non-Gaussian model of atmospheric turbulence is presented and analyzed. The model is restricted to the regions of the atmosphere where the turbulence is steady or continuous, and the assumptions of homogeneity and stationarity are justified. Also spatial distribution of turbulence is neglected, so the model consists of three independent, stationary stochastic processes which represent the vertical, lateral, and longitudinal gust components. The non-Gaussian and Gaussian models are compared with experimental data, and it is shown that the Gaussian model underestimates the number of high velocity gusts which occur in the atmosphere, while the non-Gaussian model can be adjusted to match the observed high velocity gusts more satisfactorily. Application of the proposed model to aircraft response is investigated, with particular attention to the response power spectral density, the probability distribution, and the level crossing frequency. A numerical example is presented which illustrates the application of the non-Gaussian model to the study of an aircraft autopilot system. Listings and sample results of a number of computer programs used in working with the model are included.

Comparison of Predictive Modeling Methods of Aircraft Landing Speed

NASA Technical Reports Server (NTRS)

Diallo, Ousmane H.

2012-01-01

Expected increases in air traffic demand have stimulated the development of air traffic control tools intended to assist the air traffic controller in accurately and precisely spacing aircraft landing at congested airports. Such tools will require an accurate landing-speed prediction to increase throughput while decreasing necessary controller interventions for avoiding separation violations. There are many practical challenges to developing an accurate landing-speed model that has acceptable prediction errors. This paper discusses the development of a near-term implementation, using readily available information, to estimate/model final approach speed from the top of the descent phase of flight to the landing runway. As a first approach, all variables found to contribute directly to the landing-speed prediction model are used to build a multi-regression technique of the response surface equation (RSE). Data obtained from operations of a major airlines for a passenger transport aircraft type to the Dallas/Fort Worth International Airport are used to predict the landing speed. The approach was promising because it decreased the standard deviation of the landing-speed error prediction by at least 18% from the standard deviation of the baseline error, depending on the gust condition at the airport. However, when the number of variables is reduced to the most likely obtainable at other major airports, the RSE model shows little improvement over the existing methods. Consequently, a neural network that relies on a nonlinear regression technique is utilized as an alternative modeling approach. For the reduced number of variables cases, the standard deviation of the neural network models errors represent over 5% reduction compared to the RSE model errors, and at least 10% reduction over the baseline predicted landing-speed error standard deviation. Overall, the constructed models predict the landing-speed more accurately and precisely than the current state-of-the-art.

76 FR 66205 - Airworthiness Directives; Sikorsky Aircraft Corporation Model S-76A Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-26

... Corporation Model S- 76A Helicopters AGENCY: Federal Aviation Administration, DOT. ACTION: Notice of proposed... Sikorsky Aircraft Corporation (Sikorsky) Model S-76A helicopters. This proposal would require modifying the... fire occurring in an ERB installed on a Model S- 76A helicopter. The actions specified by this proposed...

Defining the Ecological Coefficient of Performance for an Aircraft Propulsion System

NASA Astrophysics Data System (ADS)

Şöhret, Yasin

2018-05-01

The aircraft industry, along with other industries, is considered responsible these days regarding environmental issues. Therefore, the performance evaluation of aircraft propulsion systems should be conducted with respect to environmental and ecological considerations. The current paper aims to present the ecological coefficient of performance calculation methodology for aircraft propulsion systems. The ecological coefficient performance is a widely-preferred performance indicator of numerous energy conversion systems. On the basis of thermodynamic laws, the methodology used to determine the ecological coefficient of performance for an aircraft propulsion system is parametrically explained and illustrated in this paper for the first time. For a better understanding, to begin with, the exergy analysis of a turbojet engine is described in detail. Following this, the outputs of the analysis are employed to define the ecological coefficient of performance for a turbojet engine. At the end of the study, the ecological coefficient of performance is evaluated parametrically and discussed depending on selected engine design parameters and performance measures. The author asserts the ecological coefficient of performance to be a beneficial indicator for researchers interested in aircraft propulsion system design and related topics.

Turbulence modeling of free shear layers for high performance aircraft

NASA Technical Reports Server (NTRS)

Sondak, Douglas

1993-01-01

In many flowfield computations, accuracy of the turbulence model employed is frequently a limiting factor in the overall accuracy of the computation. This is particularly true for complex flowfields such as those around full aircraft configurations. Free shear layers such as wakes, impinging jets (in V/STOL applications), and mixing layers over cavities are often part of these flowfields. Although flowfields have been computed for full aircraft, the memory and CPU requirements for these computations are often excessive. Additional computer power is required for multidisciplinary computations such as coupled fluid dynamics and conduction heat transfer analysis. Massively parallel computers show promise in alleviating this situation, and the purpose of this effort was to adapt and optimize CFD codes to these new machines. The objective of this research effort was to compute the flowfield and heat transfer for a two-dimensional jet impinging normally on a cool plate. The results of this research effort were summarized in an AIAA paper titled 'Parallel Implementation of the k-epsilon Turbulence Model'. Appendix A contains the full paper.

Experimental study of UTM-LST generic half model transport aircraft

NASA Astrophysics Data System (ADS)

Ujang, M. I.; Mat, S.; Perumal, K.; Mohd. Nasir, M. N.

2016-10-01

This paper presents the experimental results from the investigation carried out at the UTM Low Speed wind tunnel facility (UTM-LST) on a half model generic transport aircraft at several configurations of primary control surfaces (flap, aileron and elevator). The objective is to measure the aerodynamic forces and moments due to the configuration changes. The study is carried out at two different speeds of 26.1 m/s and 43.1 m/s at corresponding Reynolds number of 1 × 106 and 2 × 106, respectively. Angle of attack of the model is varied between -2o to 20o. For the flaps, the deflection applied is 0o, 5o and 10o. Meanwhile, for aileron and elevator, the deflection applied is between -10o and 10o. The results show the differences in aerodynamic characteristics of the aircraft at different control surfaces configurations. The results obtained indicate that a laminar separation bubble developed on the surface of the wing at lower angles of attack and show that the separation process is delayed when the Reynolds number is increased.

Flow visualization studies of VTOL aircraft models during Hover in ground effect

NASA Technical Reports Server (NTRS)

Mourtos, Nikos J.; Couillaud, Stephane; Carter, Dale; Hange, Craig; Wardwell, Doug; Margason, Richard J.

1995-01-01

A flow visualization study of several configurations of a jet-powered vertical takeoff and landing (VTOL) aircraft model during hover in ground effect was conducted. A surface oil flow technique was used to observe the flow patterns on the lower surfaces of the model. There were significant configuration effects. Wing height with respect to fuselage, the presence of an engine inlet duct beside the fuselage, and nozzle pressure ratio are seen to have strong effects on the surface flow angles on the lower surface of the wing. This test was part of a program to improve the methods for predicting the hot gas ingestion (HGI) for jet-powered vertical/short takeoff and landing (V/STOL) aircraft. The tests were performed at the Jet Calibration and Hover Test (JCAHT) Facility at Ames Research Center.

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.

Aerodynamic Modeling of Transonic Aircraft Using Vortex Lattice Coupled with Transonic Small Disturbance for Conceptual Design

NASA Technical Reports Server (NTRS)

Chaparro, Daniel; Fujiwara, Gustavo E. C.; Ting, Eric; Nguyen, Nhan

2016-01-01

The need to rapidly scan large design spaces during conceptual design calls for computationally inexpensive tools such as the vortex lattice method (VLM). Although some VLM tools, such as Vorview have been extended to model fully-supersonic flow, VLM solutions are typically limited to inviscid, subcritical flow regimes. Many transport aircraft operate at transonic speeds, which limits the applicability of VLM for such applications. This paper presents a novel approach to correct three-dimensional VLM through coupling of two-dimensional transonic small disturbance (TSD) solutions along the span of an aircraft wing in order to accurately predict transonic aerodynamic loading and wave drag for transport aircraft. The approach is extended to predict flow separation and capture the attenuation of aerodynamic forces due to boundary layer viscosity by coupling the TSD solver with an integral boundary layer (IBL) model. The modeling framework is applied to the NASA General Transport Model (GTM) integrated with a novel control surface known as the Variable Camber Continuous Trailing Edge Flap (VCCTEF).

Aircraft Energy Conservation during Airport Ground Operations

DTIC Science & Technology

1982-03-01

minimized. The model can be run in a non -optimizing mode to simulate movements along pre-assigned taxi paths. 8-6 The model is also designed ...5.5 5.6 5.7 Engine Designation by Airline and Aircraft Type IAD 2-6 Engine Designation by Airline and Aircraft Type DCA 2-7 Fuel Flow Rates...B.2 CY 1979 Aircraft Operations at IAD and DCA Airports . . 3-5 B.3 1979 Scheduled and Non -Scheduled Departures from IAD by Aircraft Type and

77 FR 38744 - Airworthiness Directives; Sikorsky Aircraft-Manufactured Model S-64F Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-29

... the Sikorsky Aircraft Corporation-manufactured Model S-64F helicopters, now under the Erickson Air-Crane Incorporated (Erickson) Model S-64F type certificate. That AD currently requires inspections... docket shortly after receipt. For service information identified in this proposed AD, contact Erickson...

Reduced order model of a blended wing body aircraft configuration

NASA Astrophysics Data System (ADS)

Stroscher, F.; Sika, Z.; Petersson, O.

2013-12-01

This paper describes the full development process of a numerical simulation model for the ACFA2020 (Active Control for Flexible 2020 Aircraft) blended wing body (BWB) configuration. Its requirements are the prediction of aeroelastic and flight dynamic response in time domain, with relatively small model order. Further, the model had to be parameterized with regard to multiple fuel filling conditions, as well as flight conditions. High efforts have been conducted in high-order aerodynamic analysis, for subsonic and transonic regime, by several project partners. The integration of the unsteady aerodynamic databases was one of the key issues in aeroelastic modeling.

Pulsed Holographic Nondestructive Testing On Aircraft

NASA Astrophysics Data System (ADS)

Fagot, Hubert; Smigielski, Paul; Albe, Felix; Arnaud, Jean-Louis

1983-06-01

An holographic camera composed of two ruby lasers was built at ISL. It provides double exposure holograms with an adjustable time interval ranging from few ns to infinity. Various aircraft structures were first tested at ISL in laboratory conditions: honeycomb panels, wings ... The industrial tests on a military aircraft in maintenance checking were performed in a hangar of the SNIAS at Saint-Nazaire: wings, trap-door of the rear landing gear, air-brake... Electromechanical shocks were used to make the structure vibrate and to allow a fast trigger of the lasers. This avoids disturbance due to ambiant noises and vibrations.

We have just begun to create efficient transport aircraft

NASA Technical Reports Server (NTRS)

Maglieri, D. J.; Dollyhigh, S. M.

1982-01-01

Factors affecting the cost-effectiveness and economics of the air transportation industry are reviewed. The delivery of more fuel-efficient aircraft and eventual total replacement in the 1990's by fleets of advanced aircraft are seen to offset rising fuel costs. Better airport operations are perceived to eliminate fuel-costly delays due to overcrowded runways, lack of available carriers, and maintenance of aircraft in holding patterns. Noise reduction research will lower the lawsuit costs from noise pollution, and the introduction of advanced turbofans for long, short, and medium range flights, advanced commuter planes, and advanced SSTs offering projected 50% increases in current aircraft efficiencies are seen to be limited only by the airlines' ability to provide purchase financing, rather than by a lack of available new technology.

NASA Researcher Examines an Aircraft Model with a Four-Fan Thrust Reverser

NASA Image and Video Library

1972-03-21

National Aeronautics and Space Administration (NASA) researcher John Carpenter inspects an aircraft model with a four-fan thrust reverser which would be studied in the 9- by 15-Foot Low Speed Wind Tunnel at the Lewis Research Center. Thrust reversers were introduced in the 1950s as a means for slowing high-speed jet aircraft during landing. Engineers sought to apply the technology to Vertical and Short Takeoff and Landing (VSTOL) aircraft in the 1970s. The new designs would have to take into account shorter landing areas, noise levels, and decreased thrust levels. A balance was needed between the thrust reverser’s efficiency, its noise generation, and the engine’s power setting. This model underwent a series of four tests in the 9- by 15-foot tunnel during April and May 1974. The model, with a high-wing configuration and no tail, was equipped with four thrust-reverser engines. The investigations included static internal aerodynamic tests on a single fan/reverser, wind tunnel isolated fan/reverser thrust tests, installation effects on a four-fan airplane model in a wind tunnel, and single reverser acoustic tests. The 9-by 15 was built inside the return leg of the 8- by 6-Foot Supersonic Wind Tunnel in 1968. The facility generates airspeeds from 0 to 175 miles per hour to evaluate the aerodynamic performance and acoustic characteristics of nozzles, inlets, and propellers, and investigate hot gas re-ingestion of advanced VSTOL concepts. John Carpenter was a technician in the Wind Tunnels Service Section of the Test Installations Division.

Stochastic Methods for Aircraft Design

NASA Technical Reports Server (NTRS)

Pelz, Richard B.; Ogot, Madara

1998-01-01

The global stochastic optimization method, simulated annealing (SA), was adapted and applied to various problems in aircraft design. The research was aimed at overcoming the problem of finding an optimal design in a space with multiple minima and roughness ubiquitous to numerically generated nonlinear objective functions. SA was modified to reduce the number of objective function evaluations for an optimal design, historically the main criticism of stochastic methods. SA was applied to many CFD/MDO problems including: low sonic-boom bodies, minimum drag on supersonic fore-bodies, minimum drag on supersonic aeroelastic fore-bodies, minimum drag on HSCT aeroelastic wings, FLOPS preliminary design code, another preliminary aircraft design study with vortex lattice aerodynamics, HSR complete aircraft aerodynamics. In every case, SA provided a simple, robust and reliable optimization method which found optimal designs in order 100 objective function evaluations. Perhaps most importantly, from this academic/industrial project, technology has been successfully transferred; this method is the method of choice for optimization problems at Northrop Grumman.

Perm State University HPC-hardware and software services: capabilities for aircraft engine aeroacoustics problems solving

NASA Astrophysics Data System (ADS)

Demenev, A. G.

2018-02-01

The present work is devoted to analyze high-performance computing (HPC) infrastructure capabilities for aircraft engine aeroacoustics problems solving at Perm State University. We explore here the ability to develop new computational aeroacoustics methods/solvers for computer-aided engineering (CAE) systems to handle complicated industrial problems of engine noise prediction. Leading aircraft engine engineering company, including “UEC-Aviadvigatel” JSC (our industrial partners in Perm, Russia), require that methods/solvers to optimize geometry of aircraft engine for fan noise reduction. We analysed Perm State University HPC-hardware resources and software services to use efficiently. The performed results demonstrate that Perm State University HPC-infrastructure are mature enough to face out industrial-like problems of development CAE-system with HPC-method and CFD-solvers.

The atmospheric effects of stratospheric aircraft: A topical review

NASA Technical Reports Server (NTRS)

Johnston, Harold S.; Prather, M. J.; Watson, R. T.

1991-01-01

In the late 1960s the aircraft industry became interested in developing a fleet of supersonic transports (SSTs). Between 1972 and 1975, the Climatic Impact Assessment Program (CIAP) studied the possible environmental impact of SSTs. For environmental and economic reasons, the fleet of SSTs was not developed. The Upper Atmosphere Research Program (UARP) has recently undertaken the responsibility of directing scientific research needed to assess the atmospheric impact of supersonic transports. The UARP and the High-Speed Research Program asked Harold Johnston to review the current understanding of aircraft emissions and their effect on the stratosphere. Johnston and his colleagues have recently re-examined the SST problem using current models for stratospheric ozone chemistry. A unique view is given here of the current scientific issues and the lessons learned since the beginning of CIAP, and it links the current research program with the assessment process that began two years ago.

Predicted aircraft effects on stratospheric ozone

NASA Technical Reports Server (NTRS)

Ko, Malcolm K. W.; Wofsy, Steve; Kley, Dieter; Zhadin, Evgeny A.; Johnson, Colin; Weisenstein, Debra; Prather, Michael J.; Wuebbles, Donald J.

1991-01-01

The possibility that the current fleet of subsonic aircraft may already have caused detectable changes in both the troposphere and stratosphere has raised concerns about the impact of such operations on stratospheric ozone and climate. Recent interest in the operation of supersonic aircraft in the lower stratosphere has heightened such concerns. Previous assessments of impacts from proposed supersonic aircraft were based mostly on one-dimensional model results although a limited number of multidimensional models were used. In the past 15 years, our understanding of the processes that control the atmospheric concentrations of trace gases has changed dramatically. This better understanding was achieved through accumulation of kinetic data and field observations as well as development of new models. It would be beneficial to start examining the impact of subsonic aircraft to identify opportunities to study and validate the mechanisms that were proposed to explain the ozone responses. The two major concerns are the potential for a decrease in the column abundance of ozone leading to an increase in ultraviolet radiation at the ground, and redistribution of ozone in the lower stratosphere and upper troposphere leading to changes in the Earth's climate. Two-dimensional models were used extensively for ozone assessment studies, with a focus on responses to chlorine perturbations. There are problems specific to the aircraft issues that are not adequately addressed by the current models. This chapter reviews the current status of the research on aircraft impact on ozone with emphasis on immediate model improvements necessary for extending our understanding. The discussion will be limited to current and projected commercial aircraft that are equipped with air-breathing engines using conventional jet fuel. The impacts are discussed in terms of the anticipated fuel use at cruise altitude.

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.

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.

78 FR 15599 - Airworthiness Directives; Sikorsky Aircraft-Manufactured Model S-64F Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-12

... Erickson Air-Crane Incorporated (Erickson) Model S-64F type certificate. This AD supersedes an existing AD..., contact Erickson Air-Crane Incorporated, ATTN: Chris Erickson/Compliance Officer, 3100 Willow Springs Rd... Sikorsky Aircraft Corporation-manufactured Model S-64F helicopters, now under the Erickson Air-Crane...

Photochemical model evaluation of 2013 California wild fire air quality impacts using surface, aircraft, and satellite data.

PubMed

Baker, K R; Woody, M C; Valin, L; Szykman, J; Yates, E L; Iraci, L T; Choi, H D; Soja, A J; Koplitz, S N; Zhou, L; Campuzano-Jost, Pedro; Jimenez, Jose L; Hair, J W

2018-10-01

The Rim Fire was one of the largest wildfires in California history, burning over 250,000 acres during August and September 2013 affecting air quality locally and regionally in the western U.S. Routine surface monitors, remotely sensed data, and aircraft based measurements were used to assess how well the Community Multiscale Air Quality (CMAQ) photochemical grid model applied at 4 and 12 km resolution represented regional plume transport and chemical evolution during this extreme wildland fire episode. Impacts were generally similar at both grid resolutions although notable differences were seen in some secondary pollutants (e.g., formaldehyde and peroxyacyl nitrate) near the Rim fire. The modeling system does well at capturing near-fire to regional scale smoke plume transport compared to remotely sensed aerosol optical depth (AOD) and aircraft transect measurements. Plume rise for the Rim fire was well characterized as the modeled plume top was consistent with remotely sensed data and the altitude of aircraft measurements, which were typically made at the top edge of the plume. Aircraft-based lidar suggests O 3 downwind in the Rim fire plume was vertically stratified and tended to be higher at the plume top, while CMAQ estimated a more uniformly mixed column of O 3 . Predicted wildfire ozone (O 3 ) was overestimated both at the plume top and at nearby rural and urban surface monitors. Photolysis rates were well characterized by the model compared with aircraft measurements meaning aerosol attenuation was reasonably estimated and unlikely contributing to O 3 overestimates at the top of the plume. Organic carbon was underestimated close to the Rim fire compared to aircraft data, but was consistent with nearby surface measurements. Periods of elevated surface PM 2.5 at rural monitors near the Rim fire were not usually coincident with elevated O 3 . Published by Elsevier B.V.

Modeling the impact of improved aircraft operations technologies on the environment and airline behavior

NASA Astrophysics Data System (ADS)

Foley, Ryan Patrick

The overall goal of this thesis is to determine if improved operations technologies are economically viable for US airlines, and to determine the level of environmental benefits available from such technologies. Though these operational changes are being implemented primarily with the reduction of delay and improvement of throughput in mind, economic factors will drive the rate of airline adoption. In addition, the increased awareness of environmental impacts makes these effects an important aspect of decision-making. Understanding this relationship may help policymakers make decisions regarding implementation of these advanced technologies at airports, and help airlines determine appropriate levels of support to provide for these new technologies. In order to do so, the author models the behavior of a large, profit-seeking airline in response to the introduction of advanced equipage allowing improved operations procedures. The airline response included changes in deployed fleet, assignment of aircraft to routes, and acquisition of new aircraft. From these responses, changes in total fleet-level CO2 emissions and airline profit were tallied. As awareness of the environmental impact of aircraft emissions has grown, several agencies (ICAO, NASA) have moved to place goals for emissions reduction. NASA, in particular, has set goals for emissions reduction through several areas of aircraft technology. Among these are "Operational Improvements," technologies available in the short-term through avionics and airport system upgrades. The studies in this thesis make use of the Fleet-Level Environmental Evaluation Tool (FLEET), a simulation tool developed by Purdue University in support of a NASA-sponsored research effort. This tool models the behavior of a large, profit-seeking airline through an allocation problem. The problem is contained within a systems dynamics type approach that allows feedback between passenger demand, ticket price, and the airline fleet composition

MRAC Control with Prior Model Knowledge for Asymmetric Damaged Aircraft

PubMed Central

Zhang, Jing

2015-01-01

This paper develops a novel state-tracking multivariable model reference adaptive control (MRAC) technique utilizing prior knowledge of plant models to recover control performance of an asymmetric structural damaged aircraft. A modification of linear model representation is given. With prior knowledge on structural damage, a polytope linear parameter varying (LPV) model is derived to cover all concerned damage conditions. An MRAC method is developed for the polytope model, of which the stability and asymptotic error convergence are theoretically proved. The proposed technique reduces the number of parameters to be adapted and thus decreases computational cost and requires less input information. The method is validated by simulations on NASA generic transport model (GTM) with damage. PMID:26180839

Determination of Elevator and Rudder Hinge Forces on the Learjet Model 55 Aircraft

NASA Technical Reports Server (NTRS)

Boroughs, R. R.; Padmanabhan, V.

1983-01-01

The empennage structure on the Learjet 55 aircraft was quite similar to the empennage structure on earlier Learjet models. However, due to an important structural change in the vertical fin along with the new loads environment on the 50 series aircraft, a structural test was required on the vertical fin, but the horizontal tail was substantiated by a comparative analysis with previous tests. NASTRAN analysis was used to investigate empennage deflections, stress levels, and control surface hinge forces. The hinge force calculations were made with the control surfaces in the deflected as well as undeflected configurations. A skin panel buckling analysis was also performed, and the non-linear effects of buckling were simulated in the NASTRAN model to more accurately define internal loads and stress levels. Comparisons were then made between the Model 55 and the Model 35/36 stresses and internal forces to determine which components were qualified by previous tests. Some of the methods and techniques used in this analysis are described.

Application of triggered lightning numerical models to the F106B and extension to other aircraft

NASA Technical Reports Server (NTRS)

Ng, Poh H.; Dalke, Roger A.; Horembala, Jim; Rudolph, Terence; Perala, Rodney A.

1988-01-01

The goal of the F106B Thunderstorm Research Program is to characterize the lightning environment for aircraft in flight. This report describes the application of numerical electromagnetic models to this problem. Topics include: (1) Extensive application of linear triggered lightning to F106B data; (2) Electrostatic analysis of F106B field mill data; (3) Application of subgrid modeling to F106B nose region, including both static and nonlinear models; (4) Extension of F106B results to other aircraft of varying sizes and shapes; and (5) Application of nonlinear model to interaction of F106B with lightning leader-return stroke event.

Statistical aspects of carbon fiber risk assessment modeling. [fire accidents involving aircraft

NASA Technical Reports Server (NTRS)

Gross, D.; Miller, D. R.; Soland, R. M.

1980-01-01

The probabilistic and statistical aspects of the carbon fiber risk assessment modeling of fire accidents involving commercial aircraft are examined. Three major sources of uncertainty in the modeling effort are identified. These are: (1) imprecise knowledge in establishing the model; (2) parameter estimation; and (3)Monte Carlo sampling error. All three sources of uncertainty are treated and statistical procedures are utilized and/or developed to control them wherever possible.

Escorting commercial aircraft to reduce the MANPAD threat

NASA Astrophysics Data System (ADS)

Hock, Nicholas; Richardson, M. A.; Butters, B.; Walmsley, R.; Ayling, R.; Taylor, B.

2005-11-01

This paper studies the Man-Portable Air Defence System (MANPADS) threat against large commercial aircraft using flight profile analysis, engagement modelling and simulation. Non-countermeasure equipped commercial aircraft are at risk during approach and departure due to the large areas around airports that would need to be secured to prevent the use of highly portable and concealable MANPADs. A software model (CounterSim) has been developed and was used to simulate an SA-7b and large commercial aircraft engagement. The results of this simulation have found that the threat was lessened when a escort fighter aircraft is flown in the 'Centreline Low' position, or 25 m rearward from the large aircraft and 15 m lower, similar to the Air-to-Air refuelling position. In the model a large aircraft on approach had a 50% chance of being hit or having a near miss (within 20m) whereas escorted by a countermeasure equipped F-16 in the 'Centerline Low' position, this was reduced to only 14%. Departure is a particularly vulnerable time for large aircraft due to slow climb rates and the inability to fly evasive manoeuvres. The 'Centreline Low' escorted departure greatly reduced the threat to 16% hit or near miss from 62% for an unescorted heavy aircraft. Overall the CounterSim modelling has showed that escorting a civilian aircraft on approach and departure can reduce the MANPAD threat by 3 to 4 times.

Finite Element Aircraft Simulation of Turbulence

NASA Technical Reports Server (NTRS)

McFarland, R. E.

1997-01-01

A turbulence model has been developed for realtime aircraft simulation that accommodates stochastic turbulence and distributed discrete gusts as a function of the terrain. This model is applicable to conventional aircraft, V/STOL aircraft, and disc rotor model helicopter simulations. Vehicle angular activity in response to turbulence is computed from geometrical and temporal relationships rather than by using the conventional continuum approximations that assume uniform gust immersion and low frequency responses. By using techniques similar to those recently developed for blade-element rotor models, the angular-rate filters of conventional turbulence models are not required. The model produces rotational rates as well as air mass translational velocities in response to both stochastic and deterministic disturbances, where the discrete gusts and turbulence magnitudes may be correlated with significant terrain features or ship models. Assuming isotropy, a two-dimensional vertical turbulence field is created. A novel Gaussian interpolation technique is used to distribute vertical turbulence on the wing span or lateral rotor disc, and this distribution is used to compute roll responses. Air mass velocities are applied at significant centers of pressure in the computation of the aircraft's pitch and roll responses.

Aircraft operability methods applied to space launch vehicles

NASA Astrophysics Data System (ADS)

Young, Douglas

1997-01-01

The commercial space launch market requirement for low vehicle operations costs necessitates the application of methods and technologies developed and proven for complex aircraft systems. The ``building in'' of reliability and maintainability, which is applied extensively in the aircraft industry, has yet to be applied to the maximum extent possible on launch vehicles. Use of vehicle system and structural health monitoring, automated ground systems and diagnostic design methods derived from aircraft applications support the goal of achieving low cost launch vehicle operations. Transforming these operability techniques to space applications where diagnostic effectiveness has significantly different metrics is critical to the success of future launch systems. These concepts will be discussed with reference to broad launch vehicle applicability. Lessons learned and techniques used in the adaptation of these methods will be outlined drawing from recent aircraft programs and implementation on phase 1 of the X-33/RLV technology development program.

Thrust Vectoring Nozzle for Modern Military Aircraft

DTIC Science & Technology

2000-05-11

Thrust Vectoring Nozzle for Modern Military Aircraft Daniel Ikaza Industria de Turbo Propulsores S.A. (ITP) Parque Tecnol6gico, edificio 300 48170...programme has only been possible with the contribution of partners and organizations, namely: Spanish Ministries of Industry and Defence, with

User's manual for LINEAR, a FORTRAN program to derive linear aircraft models

NASA Technical Reports Server (NTRS)

Duke, Eugene L.; Patterson, Brian P.; Antoniewicz, Robert F.

1987-01-01

This report documents a FORTRAN program that provides a powerful and flexible tool for the linearization of aircraft models. The program LINEAR numerically determines a linear system model using nonlinear equations of motion and a user-supplied nonlinear aerodynamic model. The system model determined by LINEAR consists of matrices for both state and observation equations. The program has been designed to allow easy selection and definition of the state, control, and observation variables to be used in a particular model.

Comparison of alternate fuels for aircraft

NASA Technical Reports Server (NTRS)

Witcofski, R. D.

1979-01-01

A comparison of candidate alternate fuels for aircraft is presented. The fuels discussed include liquid hydrogen, liquid methane, and synthetic aviation kerosene. Each fuel is evaluated from the standpoint of production, transmission, airport storage and distribution facilities, and use in aircraft. Technology deficient areas for cryogenic fuels, which should be advanced prior to the introduction of the fuels into the aviation industry, are identified, as are the cost and energy penalties associated with not achieving those advances. Environmental emissions and safety aspects of fuel selection are discussed. A detailed description of the various fuel production and liquefaction processes and their efficiencies and economics is given.

75 FR 7405 - Airworthiness Directives; British Aerospace Regional Aircraft Model Jetstream Series 3101 and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-19

... Airworthiness Directives; British Aerospace Regional Aircraft Model Jetstream Series 3101 and Jetstream Model... available in the AD docket shortly after receipt. FOR FURTHER INFORMATION CONTACT: Taylor Martin, Aerospace... AD docket. Relevant Service Information BAE Systems has issued British Aerospace Jetstream Series...

Revision of civil aircraft noise data for the Integrated Noise Model (INM)

DOT National Transportation Integrated Search

1986-09-30

This report provides noise data for the Integrated Noise Model (INM) and is referred to as data base number nine. Air-to-ground sound level versus distance data for civil (and some military) aircraft in a form useful for airport noise contour computa...

Aircraft modifications: Assessing the current state of Air Force aircraft modifications and the implications for future military capability

NASA Astrophysics Data System (ADS)

Hill, Owen Jacob

How prepared is the U.S. Air Force to modify its aircraft fleet in upcoming years? Aircraft modernization is a complex interaction of new and legacy aircraft, organizational structure, and planning policy. This research will take one component of modernization: aircraft modification, and apply a new method of analysis in order to help formulate policy to promote modernization. Departing from previous small-sample studies dependent upon weight as a chief explanatory variable, this dissertation incorporates a comprehensive dataset that was constructed for this research of all aircraft modifications from 1996 through 2005. With over 700 modification programs, this dataset is used to examine changes to the current modification policy using policy-response regression models. These changes include separating a codependent procurement and installation schedule, reducing the documentation requirements for safety modifications, and budgeting for aging aircraft modifications. The research then concludes with predictive models for the F-15 and F-16 along with their replacements: the F-22 and F-35 Joint Strike Fighter.

Life modeling of thermal barrier coatings for aircraft gas turbine engines

NASA Technical Reports Server (NTRS)

Miller, R. A.

1989-01-01

Thermal barrier coating life models developed under the NASA Lewis Research Center's Hot Section Technology (HOST) Program are summarized. An initial laboratory model and three design-capable models are discussed. Current understanding of coating failure mechanisms are also summarized. The materials and structural aspects of thermal barrier coatings have been successfully integrated under the HOST program to produce models which may now or in the near future be used in design. Efforts on this program continue at Pratt and Whitney Aircraft where their model is being extended to the life prediction of physical vapor deposited thermal barrier coatings.

Automation of reverse engineering process in aircraft modeling and related optimization problems

NASA Technical Reports Server (NTRS)

Li, W.; Swetits, J.

1994-01-01

During the year of 1994, the engineering problems in aircraft modeling were studied. The initial concern was to obtain a surface model with desirable geometric characteristics. Much of the effort during the first half of the year was to find an efficient way of solving a computationally difficult optimization model. Since the smoothing technique in the proposal 'Surface Modeling and Optimization Studies of Aerodynamic Configurations' requires solutions of a sequence of large-scale quadratic programming problems, it is important to design algorithms that can solve each quadratic program in a few interactions. This research led to three papers by Dr. W. Li, which were submitted to SIAM Journal on Optimization and Mathematical Programming. Two of these papers have been accepted for publication. Even though significant progress has been made during this phase of research and computation times was reduced from 30 min. to 2 min. for a sample problem, it was not good enough for on-line processing of digitized data points. After discussion with Dr. Robert E. Smith Jr., it was decided not to enforce shape constraints in order in order to simplify the model. As a consequence, P. Dierckx's nonparametric spline fitting approach was adopted, where one has only one control parameter for the fitting process - the error tolerance. At the same time the surface modeling software developed by Imageware was tested. Research indicated a substantially improved fitting of digitalized data points can be achieved if a proper parameterization of the spline surface is chosen. A winning strategy is to incorporate Dierckx's surface fitting with a natural parameterization for aircraft parts. The report consists of 4 chapters. Chapter 1 provides an overview of reverse engineering related to aircraft modeling and some preliminary findings of the effort in the second half of the year. Chapters 2-4 are the research results by Dr. W. Li on penalty functions and conjugate gradient methods for

Neural network adaptive control of wing-rock motion of aircraft model mounted on three-degree-of-freedom dynamic rig in wind tunnel

NASA Astrophysics Data System (ADS)

Ignatyev, D. I.

2018-06-01

High-angles-of-attack dynamics of aircraft are complicated with dangerous phenomena such as wing rock, stall, and spin. Autonomous dynamically scaled aircraft model mounted in three-degree-of-freedom (3DoF) dynamic rig is proposed for studying aircraft dynamics and prototyping of control laws in wind tunnel. Dynamics of the scaled aircraft model in 3DoF manoeuvre rig in wind tunnel is considered. The model limit-cycle oscillations are obtained at high angles of attack. A neural network (NN) adaptive control suppressing wing rock motion is designed. The wing rock suppression with the proposed control law is validated using nonlinear time-domain simulations.

Scanner imaging systems, aircraft

NASA Technical Reports Server (NTRS)

Ungar, S. G.

1982-01-01

The causes and effects of distortion in aircraft scanner data are reviewed and an approach to reduce distortions by modelling the effect of aircraft motion on the scanner scene is discussed. With the advent of advanced satellite borne scanner systems, the geometric and radiometric correction of aircraft scanner data has become increasingly important. Corrections are needed to reliably simulate observations obtained by such systems for purposes of evaluation. It is found that if sufficient navigational information is available, aircraft scanner coordinates may be related very precisely to planimetric ground coordinates. However, the potential for a multivalue remapping transformation (i.e., scan lines crossing each other), adds an inherent uncertainty, to any radiometric resampling scheme, which is dependent on the precise geometry of the scan and ground pattern.

Multi-Sensor Fusion with Interacting Multiple Model Filter for Improved Aircraft Position Accuracy

PubMed Central

Cho, Taehwan; Lee, Changho; Choi, Sangbang

2013-01-01

The International Civil Aviation Organization (ICAO) has decided to adopt Communications, Navigation, and Surveillance/Air Traffic Management (CNS/ATM) as the 21st century standard for navigation. Accordingly, ICAO members have provided an impetus to develop related technology and build sufficient infrastructure. For aviation surveillance with CNS/ATM, Ground-Based Augmentation System (GBAS), Automatic Dependent Surveillance-Broadcast (ADS-B), multilateration (MLAT) and wide-area multilateration (WAM) systems are being established. These sensors can track aircraft positions more accurately than existing radar and can compensate for the blind spots in aircraft surveillance. In this paper, we applied a novel sensor fusion method with Interacting Multiple Model (IMM) filter to GBAS, ADS-B, MLAT, and WAM data in order to improve the reliability of the aircraft position. Results of performance analysis show that the position accuracy is improved by the proposed sensor fusion method with the IMM filter. PMID:23535715

Multi-sensor fusion with interacting multiple model filter for improved aircraft position accuracy.

PubMed

Cho, Taehwan; Lee, Changho; Choi, Sangbang

2013-03-27

The International Civil Aviation Organization (ICAO) has decided to adopt Communications, Navigation, and Surveillance/Air Traffic Management (CNS/ATM) as the 21st century standard for navigation. Accordingly, ICAO members have provided an impetus to develop related technology and build sufficient infrastructure. For aviation surveillance with CNS/ATM, Ground-Based Augmentation System (GBAS), Automatic Dependent Surveillance-Broadcast (ADS-B), multilateration (MLAT) and wide-area multilateration (WAM) systems are being established. These sensors can track aircraft positions more accurately than existing radar and can compensate for the blind spots in aircraft surveillance. In this paper, we applied a novel sensor fusion method with Interacting Multiple Model (IMM) filter to GBAS, ADS-B, MLAT, and WAM data in order to improve the reliability of the aircraft position. Results of performance analysis show that the position accuracy is improved by the proposed sensor fusion method with the IMM filter.

Airframe noise of a small model transport aircraft and scaling effects

NASA Astrophysics Data System (ADS)

Shearin, J. G.

1981-05-01

Airframe noise of a 0.01 scale model Boeing 747 wide-body transport was measured in the Langley Anechoic Noise Facility. The model geometry simulated the landing and cruise configurations. The model noise was found to be similar in noise characteristics to that possessed by a 0.03 scale model 747. The 0.01 scale model noise data scaled to within 3 dB of full scale data using the same scaling relationships as that used to scale the 0.03 scale model noise data. The model noise data are compared with full scale noise data, where the full scale data are calculated using the NASA aircraft noise prediction program.

A Grounded Theory Study of Aircraft Maintenance Technician Decision-Making

NASA Astrophysics Data System (ADS)

Norcross, Robert

related to decision-making. Recommendations included an in-depth systematic review of the Aircraft Maintenance Manuals, development of a Federal Aviation Administration approved standardized Aircraft Maintenance Technician decision-making flow diagram, and implementation of risk based decision-making training. The benefit of this study is to save the airline industry revenue by preventing poor decision-making practices that result in inefficient maintenance actions and aircraft incidents and accidents.

Study of future world markets for agricultural aircraft

NASA Technical Reports Server (NTRS)

Gobetz, F. W.; Assarabowski, R. J.

1979-01-01

The future world market for US-manufactured agricultural aircraft was studied and the technology needs for foreign markets were identified. Special emphasis was placed on the developing country market, but the developed countries and the communist group were also included in the forecasts. Aircraft needs were projected to the year 2000 by a method which accounted for field size, crop production, treated area, productivity, and attrition of the fleet. A special scenario involving a significant shift toward aerial fertilization was also considered. An operations analysis was conducted to compare the relative application costs of various existing and hypothetical future aircraft. A case study was made of Colombia as an example of a developing country in which aviation is emerging as an important industry.

Current Methods for Modeling and Simulating Icing Effects on Aircraft Performance, Stability and Control

NASA Technical Reports Server (NTRS)

Ralvasky, Thomas P.; Barnhart, Billy P.; Lee, Sam

2008-01-01

Icing alters the shape and surface characteristics of aircraft components, which results in altered aerodynamic forces and moments caused by air flow over those iced components. The typical effects of icing are increased drag, reduced stall angle of attack, and reduced maximum lift. In addition to the performance changes, icing can also affect control surface effectiveness, hinge moments, and damping. These effects result in altered aircraft stability and control and flying qualities. Over the past 80 years, methods have been developed to understand how icing affects performance, stability and control. Emphasis has been on wind tunnel testing of two-dimensional subscale airfoils with various ice shapes to understand their effect on the flow field and ultimately the aerodynamics. This research has led to wind tunnel testing of subscale complete aircraft models to identify the integrated effects of icing on the aircraft system in terms of performance, stability, and control. Data sets of this nature enable pilot in the loop simulations to be performed for pilot training, or engineering evaluation of system failure impacts or control system design.

Impact of aircraft emissions on air quality in the vicinity of airports. Volume II. An updated model assessment of aircraft generated air pollution at LAX, JFK, and ORD. Final report Jan 1978-Jul 1980

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamartino, R.J.; Smith, D.G.; Bremer, S.A.

1980-07-01

This report documents the results of the Federal Aviation Administration (FAA)/Environmental Protection Agency (EPA) air quality study which has been conducted to assess the impact of aircraft emissions of carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx) in the vicinity of airports. This assessment includes the results of recent modeling and monitoring efforts at Washington National (DCA), Los Angeles International (LAX), Dulles International (IAD), and Lakeland, Florida airports and an updated modeling of aircraft generated pollution at LAX, John F. Kennedy (JFK) and Chicago O'Hare (ORD) airports. The Airport Vicinity Air Pollution (AVAP) model which was designed formore » use at civil airports was used in this assessment. In addition the results of the application of the military version of the AVAP model the Air Quality Assessment Model (AQAM), are summarized. Both the results of the pollution monitoring analyses in Volume I and the modeling studies in Volume II suggest that: maximum hourly average CO concentrations from aircraft are unlikely to exceed 5 parts per million (ppm) in areas of public exposure and are thus small in comparison to the National Ambient Air Quality Standard of 35 ppm; maximum hourly HC concentrations from aircraft can exceed 0.25 ppm over an area several times the size of the airport; and annual average NO2 concentrations from aircraft are estimated to contribute only 10 to 20 percent of the NAAQS limit level.« less

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.

Full-envelope aerodynamic modeling of the Harrier aircraft

NASA Technical Reports Server (NTRS)

Mcnally, B. David

1986-01-01

A project to identify a full-envelope model of the YAV-8B Harrier using flight-test and parameter identification techniques is described. As part of the research in advanced control and display concepts for V/STOL aircraft, a full-envelope aerodynamic model of the Harrier is identified, using mathematical model structures and parameter identification methods. A global-polynomial model structure is also used as a basis for the identification of the YAV-8B aerodynamic model. State estimation methods are used to ensure flight data consistency prior to parameter identification.Equation-error methods are used to identify model parameters. A fixed-base simulator is used extensively to develop flight test procedures and to validate parameter identification software. Using simple flight maneuvers, a simulated data set was created covering the YAV-8B flight envelope from about 0.3 to 0.7 Mach and about -5 to 15 deg angle of attack. A singular value decomposition implementation of the equation-error approach produced good parameter estimates based on this simulated data set.

Navier-Stokes computations useful in aircraft design

NASA Technical Reports Server (NTRS)

Holst, Terry L.

1990-01-01

Large scale Navier-Stokes computations about aircraft components as well as reasonably complete aircraft configurations are presented and discussed. Speed and memory requirements are described for various general problem classes, which in some cases are already being used in the industrial design environment. Recent computed results, with experimental comparisons when available, are included to highlight the presentation. Finally, prospects for the future are described and recommendations for areas of concentrated research are indicated. The future of Navier-Stokes computations is seen to be rapidly expanding across a broad front of applications, which includes the entire subsonic-to-hypersonic speed regime.

The design of two sonic boom wind tunnel models from conceptual aircraft which cruise at Mach numbers of 2.0 and 3.0

NASA Technical Reports Server (NTRS)

Mack, Robert J.; Needleman, Kathy E.

1990-01-01

A method for designing wind tunnel models of conceptual, low-boom, supersonic cruise aircraft is presented. Also included is a review of the procedures used to design the conceptual low-boom aircraft. In the discussion, problems unique to, and encountered during, the design of both the conceptual aircraft and the wind tunnel models are outlined. The sensitivity of low-boom characteristics in the aircraft design to control the volume and lift equivalent area distributions was emphasized. Solutions to these problems are reported; especially the two which led to the design of the wind tunnel model support stings.

Insecticide Exposures on Commercial Aircraft: A Literature Review and Screening Level Assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maddalena, Randy I.; McKone, Thomas E.

2008-10-01

sampler, based on a thin-film polymer-coated glass design, was developed specifically for deployment in the airliner ventilation system for long-term unattended monitoring of insecticide loading in the aircraft. Because access was not available for either treated aircraft or treatment records during the course of this study, the development and calibration of the passive samplers was halted prior to completion. Continued development of a field ready passive sampler for insecticides in aircraft would require collaboration with the airline industry to finalize the method for deployment and calibration conditions for the sampler. The Task 3 screening level modeling assessment used a dynamic two-box mass balance model that includes treated surfaces and air to explore the time-concentration history of insecticides in the cabin. The model was parameterized using information gathered during the literature review and run for several different insecticide use scenarios. Chemical degradation or sequestration in the surface compartment and mass transfer from the surface to the air limit the rate at which insecticides are removed from the system. This rate limiting process can result in an accumulation of insecticide in the airliner cabin following repeated applications. The extent of accumulation is a function of the overall persistence of the chemical in the system and the amount of chemical applied during each treatment.« less

Aircraft technology opportunities for the 21st Century

NASA Technical Reports Server (NTRS)

Albers, James A.; Zuk, John

1988-01-01

New aircraft technologies are presented that have the potential to expand the air transportation system and reduce congestion through new operating capabilities, and at the same time provide greater levels of safety and environmental compatibility. Both current and planned civil aeronautics technology at the NASA Ames, Lewis, and Langley Research Centers are addressed. The complete spectrum of current aircraft and new vehicle concepts is considered including rotorcraft (helicopters and tiltrotors), vertical and short takeoff and landing (V/STOL) and short takeoff and landing (STOL) aircraft, subsonic transports, high speed transports, and hypersonic/transatmospheric vehicles. New technologies for current aircraft will improve efficiency, affordability, safety, and environmental compatibility. Research and technology promises to enable development of new vehicles that will revolutionize or greatly change the transportation system. These vehicles will provide new capabilities which will lead to enormous market opportunities and economic growth, as well as improve the competitive position of the U.S. aerospace industry.

General Aviation Light Aircraft Propulsion: From the 1940's to the Next Century

NASA Technical Reports Server (NTRS)

Burkardt, Leo A.

1998-01-01

Current general aviation light aircraft are powered by engines that were originally designed in the 1940's. This paper gives a brief history of light aircraft engine development, explaining why the air-cooled, horizontally opposed piston engine became the dominant engine for this class of aircraft. Current engines are fairly efficient, and their designs have been updated through the years, but their basic design and operational characteristics are archaic in comparison to modem engine designs, such as those used in the automotive industry. There have been some innovative engine developments, but in general they have not been commercially successful. This paper gives some insight into the reasons for this lack of success. There is now renewed interest in developing modem propulsion systems for light aircraft, in the fore-front of which is NASA's General Aviation Propulsion (GAP) program. This paper gives an overview of the engines being developed in the GAP program, what they will mean to the general aviation community, and why NASA and its industry partners believe that these new engine developments will bring about a new era in general aviation light aircraft.

Modeling of aircraft deicing fluids deposition

DOT National Transportation Integrated Search

2000-06-18

Glycol deposition near aircraft during deicing operations has become an important consideration at major airports. A sampling process was used to quantify glycol deposition from deicing operations at a major international airport. The resulting data ...

Aircraft Loss of Control Study

NASA Technical Reports Server (NTRS)

Jacobson, Steven R.

2010-01-01

Loss of control has become the leading cause of jet fatalities worldwide. Aside from their frequency of occurrence, accidents resulting from loss of aircraft control seize the public s attention by yielding large numbers of fatalities in a single event. In response to the rising threat to aviation safety, NASA's Aviation Safety Program has conducted a study of the loss of control problem. This study gathered four types of information pertaining to loss of control accidents: (1) statistical data; (2) individual accident reports that cite loss of control as a contributing factor; (3) previous meta-analyses of loss of control accidents; and (4) inputs solicited from aircraft manufacturers, air carriers, researchers, and other industry stakeholders. Using these information resources, the study team identified causal factors that were cited in the greatest number of loss of control accidents, and which were emphasized most by industry stakeholders. For each causal factor that was linked to loss of control, the team solicited ideas about what solutions are required and future research efforts that could potentially help avoid their occurrence or mitigate their consequences when they occurred in flight.

Heat generation in aircraft tires under free rolling conditions

NASA Technical Reports Server (NTRS)

Clark, S. K.; Dodge, R. N.

1980-01-01

Effort is directed toward construction of a rational method for evaluating internal temperatures of aircraft tires. Enhanced predictability of tire temperature buildup is a design tool in both the tire and airframe industries.

Laboratory modeling and analysis of aircraft-lightning interactions

NASA Technical Reports Server (NTRS)

Turner, C. D.; Trost, T. F.

1982-01-01

Modeling studies of the interaction of a delta wing aircraft with direct lightning strikes were carried out using an approximate scale model of an F-106B. The model, which is three feet in length, is subjected to direct injection of fast current pulses supplied by wires, which simulate the lightning channel and are attached at various locations on the model. Measurements are made of the resulting transient electromagnetic fields using time derivative sensors. The sensor outputs are sampled and digitized by computer. The noise level is reduced by averaging the sensor output from ten input pulses at each sample time. Computer analysis of the measured fields includes Fourier transformation and the computation of transfer functions for the model. Prony analysis is also used to determine the natural frequencies of the model. Comparisons of model natural frequencies extracted by Prony analysis with those for in flight direct strike data usually show lower damping in the in flight case. This is indicative of either a lightning channel with a higher impedance than the wires on the model, only one attachment point, or short streamers instead of a long channel.

Development Cycle Time Simulation for Civil Aircraft

NASA Technical Reports Server (NTRS)

Spitz, William; Berardino, Frank; Golaszewski, Richard; Johnson, Jesse

2001-01-01

Cycle Time Reduction (CTR) will be one of the major factors affecting the future of the civil aerospace industry. This focus is the end reflection of the level of competition in the commercial large carrier aircraft industry. Aircraft manufacturer must minimize costs and pass a portion of those savings onto buyers. CTR is one strategy used to move the manufacturing firm down the cost curve. The current NASA Airframe Development Cycle Time Reduction Goal is 50% by year 2022. This goal is not achievable based on the program analysis done by the LMI/GRA team. This may mean that the current roster of NASA CTR programs needs to be reexamined or that the program technology progress factors, as determined by the NASA experts, were understated. Programs that duplicate the reductions of others should be replaced with non-duplicative programs. In addition, new programs targeting a specific part of the cycle can be developed.

Industrial garnet

USGS Publications Warehouse

Olson, D.W.

2000-01-01

The state of the global industrial garnet industry in 1999 is discussed. Industrial garnet mined in the U.S., which accounts for approximately one-third of the world's total, is usually a solid-solution of almandine and pyrope. The U.S. is the largest consumer of industrial garnet, using an estimated 47,800 st in 1999 as an abrasive and as a filtration medium in the petroleum industry, filtration plants, aircraft and motor vehicle manufacture, shipbuilding, wood furniture finishing operations, electronic component manufacture, ceramics manufacture, and glass production. Prices for crude concentrates ranged from approximately $50 to $110/st and refined garnet from $50 to $215/st in 1999, depending on type, source, quantity purchased, quality, and application.

Comprehensive analysis of transport aircraft flight performance

NASA Astrophysics Data System (ADS)

Filippone, Antonio

2008-04-01

This paper reviews the state-of-the art in comprehensive performance codes for fixed-wing aircraft. The importance of system analysis in flight performance is discussed. The paper highlights the role of aerodynamics, propulsion, flight mechanics, aeroacoustics, flight operation, numerical optimisation, stochastic methods and numerical analysis. The latter discipline is used to investigate the sensitivities of the sub-systems to uncertainties in critical state parameters or functional parameters. The paper discusses critically the data used for performance analysis, and the areas where progress is required. Comprehensive analysis codes can be used for mission fuel planning, envelope exploration, competition analysis, a wide variety of environmental studies, marketing analysis, aircraft certification and conceptual aircraft design. A comprehensive program that uses the multi-disciplinary approach for transport aircraft is presented. The model includes a geometry deck, a separate engine input deck with the main parameters, a database of engine performance from an independent simulation, and an operational deck. The comprehensive code has modules for deriving the geometry from bitmap files, an aerodynamics model for all flight conditions, a flight mechanics model for flight envelopes and mission analysis, an aircraft noise model and engine emissions. The model is validated at different levels. Validation of the aerodynamic model is done against the scale models DLR-F4 and F6. A general model analysis and flight envelope exploration are shown for the Boeing B-777-300 with GE-90 turbofan engines with intermediate passenger capacity (394 passengers in 2 classes). Validation of the flight model is done by sensitivity analysis on the wetted area (or profile drag), on the specific air range, the brake-release gross weight and the aircraft noise. A variety of results is shown, including specific air range charts, take-off weight-altitude charts, payload-range performance

The scaling of model test results to predict intake hot gas reingestion for STOVL aircraft with augmented vectored thrust engines

NASA Technical Reports Server (NTRS)

Penrose, C. J.

1987-01-01

The difficulties of modeling the complex recirculating flow fields produced by multiple jet STOVL aircraft close to the ground have led to extensive use of experimental model tests to predict intake Hot Gas Reingestion (HGR). Model test results reliability is dependent on a satisfactory set of scaling rules which must be validated by fully comparable full scale tests. Scaling rules devised in the U.K. in the mid 60's gave good model/full scale agreement for the BAe P1127 aircraft. Until recently no opportunity has occurred to check the applicability of the rules to the high energy exhaust of current ASTOVL aircraft projects. Such an opportunity has arisen following tests on a Tethered Harrier. Comparison of this full scale data and results from tests on a model configuration approximating to the full scale aircraft geometry has shown discrepancies between HGR levels. These discrepancies although probably due to geometry and other model/scale differences indicate some reexamination of the scaling rules is needed. Therefore the scaling rules are reviewed, further scaling studies planned are described and potential areas for further work are suggested.

75 FR 22517 - Airworthiness Directives; British Aerospace Regional Aircraft Model Jetstream Series 3101 and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-29

... Airworthiness Directives; British Aerospace Regional Aircraft Model Jetstream Series 3101 and Jetstream Model... INFORMATION CONTACT: Taylor Martin, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301... [Amended] 0 2. The FAA amends Sec. 39.13 by adding the following new AD: 2010-09-02 British Aerospace...

Half Wing N219 Aircraft Model Clean Configuration for Flutter Test On Low Speed Wind Tunnel

NASA Astrophysics Data System (ADS)

Syamsuar, Sayuti; Sampurno, Budi; Mayang Mahasti, Katia; Bayu Sakti Pratama, Muchamad; Widi Sasongko, Triyono; Kartika, Nina; Suksmono, Adityo; Aji Saputro, Mohamad Ivan; Bahtera Eskayudha, Dimas

2018-04-01

Flutter is a rapid self-feeding motion which is caused by the interaction of aerodynamic, structural and inertial forces. Flutter can cause major damage on aircraft structure which can lead to fatal accident in aviation. Several methods have been evolved to avoid the flutter phenomena occur during the flight envelope of aircraft design. On this study, method was developed by Indonesian Aerospace which consist of Finite Element Method (FEM) analysis, Ground Vibration Test (GVT), and Wind Tunnel Flutter Test (WTT). Based on the study, FEM have similar results toward to Wind Tunnel Flutter Test conjunction the clean configuration of N219 aircraft half wing model.

The lift-fan powered-lift aircraft concept: Lessons learned

NASA Technical Reports Server (NTRS)

Deckert, Wallace H.

1993-01-01

This is one of a series of reports on the lessons learned from past research related to lift-fan aircraft concepts. An extensive review is presented of the many lift-fan aircraft design studies conducted by both government and industry over the past 45 years. Mission applications and design integration including discussions on manifolding hot gas generators, hot gas dusting, and energy transfer control are addressed. Past lift-fan evaluations of the Avrocar are discussed. Lessons learned from these past efforts are identified.

Evaluation of a Wake Vortex Upset Model Based on Simultaneous Measurements of Wake Velocities and Probe-Aircraft Accelerations

NASA Technical Reports Server (NTRS)

Short, B. J.; Jacobsen, R. A.

1979-01-01

Simultaneous measurements were made of the upset responses experienced and the wake velocities encountered by an instrumented Learjet probe aircraft behind a Boeing 747 vortex-generating aircraft. The vortex-induced angular accelerations experienced could be predicted within 30% by a mathematical upset response model when the characteristics of the wake were well represented by the vortex model. The vortex model used in the present study adequately represented the wake flow field when the vortices dissipated symmetrically and only one vortex pair existed in the wake.

76 FR 12845 - Airworthiness Directives; APEX Aircraft Model CAP 10 B Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-09

... Airworthiness Directives; APEX Aircraft Model CAP 10 B Airplanes AGENCY: Federal Aviation Administration (FAA... CAP 10C, in which the pilot lost control of the aeroplane. The following investigation has revealed... a CAP 10C, in which the pilot lost control of the aeroplane. The following investigation has...

Technical change in US industry: A cross-industry analysis

NASA Technical Reports Server (NTRS)

Nelson, R. R. (Editor)

1981-01-01

The nature of the public policies which have influenced the pace and pattern of technical progress in a number of American industries is studied with the view of assessing the broad effects of these policies. The industries studied are agriculture, pharmaceuticals, semiconductors, computers, civil aircraft, automobiles and residential construction. The policies considered include research and development funding as well as government procurement, education, information dissemination, patent protection, licensing, regulations, and anti-trust policies.

Systems study of transport aircraft incorporating advanced aluminum alloys

NASA Technical Reports Server (NTRS)

Sakata, I. F.

1982-01-01

A study was performed to quantify the potential benefits of utilizing advanced aluminum alloys in commercial transport aircraft and to define the effort necessary to develop fully the alloys to a viable commercial production capability. The comprehensive investigation (1) established realistic advanced aluminum alloy property goals to maximize aircraft systems effectiveness (2) identified performance and economic benefits of incorporating the advanced alloy in future advanced technology commercial aircraft designs (3) provided a recommended plan for development and integration of the alloys into commercial aircraft production (4) provided an indication of the timing and investigation required by the metal producing industry to support the projected market and (5) evaluate application of advanced aluminum alloys to other aerospace and transit systems as a secondary objective. The results of the investigation provided a roadmap and identified key issues requiring attention in an advanced aluminum alloy and applications technology development program.

Numerical modeling of runback water on ice protected aircraft surfaces

NASA Technical Reports Server (NTRS)

Al-Khalil, Kamel M.; Keith, Theo G., Jr.; Dewitt, Kenneth J.

1992-01-01

A numerical simulation for 'running wet' aircraft anti-icing systems is developed. The model includes breakup of the water film, which exists in regions of direct impingement, into individual rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted in the numerical solution procedure. The solid wall is modeled as a multilayer structure and the anti-icing system used is of the thermal type utilizing hot air and/or electrical heating elements embedded with the layers. Details of the calculation procedure and the methods used are presented.

Study of materials performance model for aircraft interiors

NASA Technical Reports Server (NTRS)

Leary, K.; Skratt, J.

1980-01-01

A demonstration version of an aircraft interior materials computer data library was developed and contains information on selected materials applicable to aircraft seats and wall panels, including materials for the following: panel face sheets, bond plies, honeycomb, foam, decorative film systems, seat cushions, adhesives, cushion reinforcements, fire blocking layers, slipcovers, decorative fabrics and thermoplastic parts. The information obtained for each material pertains to the material's performance in a fire scenario, selected material properties and several measures of processability.

Aircraft icing research at NASA

NASA Technical Reports Server (NTRS)

Reinmann, J. J.; Shaw, R. J.; Olsen, W. A., Jr.

1982-01-01

Research activity is described for: ice protection systems, icing instrumentation, experimental methods, analytical modeling for the above, and in flight research. The renewed interest in aircraft icing has come about because of the new need for All-Weather Helicopters and General Aviation aircraft. Because of increased fuel costs, tomorrow's Commercial Transport aircraft will also require new types of ice protection systems and better estimates of the aeropenalties caused by ice on unprotected surfaces. The physics of aircraft icing is very similar to the icing that occurs on ground structures and structures at sea; all involve droplets that freeze on the surfaces because of the cold air. Therefore all icing research groups will benefit greatly by sharing their research information.

Modelling of the automatic stabilization system of the aircraft course by a fuzzy logic method

NASA Astrophysics Data System (ADS)

Mamonova, T.; Syryamkin, V.; Vasilyeva, T.

2016-04-01

The problem of the present paper concerns the development of a fuzzy model of the system of an aircraft course stabilization. In this work modelling of the aircraft course stabilization system with the application of fuzzy logic is specified. Thus the authors have used the data taken for an ordinary passenger plane. As a result of the study the stabilization system models were realised in the environment of Matlab package Simulink on the basis of the PID-regulator and fuzzy logic. The authors of the paper have shown that the use of the method of artificial intelligence allows reducing the time of regulation to 1, which is 50 times faster than the time when standard receptions of the management theory are used. This fact demonstrates a positive influence of the use of fuzzy regulation.

Optimal Tuner Selection for Kalman-Filter-Based Aircraft Engine Performance Estimation

NASA Technical Reports Server (NTRS)

Simon, Donald L.; Garg, Sanjay

2011-01-01

applications such as model-based diagnostic, controls, and life usage calculations. The advantage of the innovation is the significant reduction in estimation errors that it can provide relative to the conventional approach of selecting a subset of health parameters to serve as the model tuning parameter vector. Because this technique needs only to be performed during the system design process, it places no additional computation burden on the onboard Kalman filter implementation. The technique has been developed for aircraft engine onboard estimation applications, as this application typically presents an under-determined estimation problem. However, this generic technique could be applied to other industries using gas turbine engine technology.

Congestion Pricing for Aircraft Pushback Slot Allocation.

PubMed

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Congestion Pricing for Aircraft Pushback Slot Allocation

PubMed Central

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Aircraft Loss of Control Causal Factors and Mitigation Challenges

NASA Technical Reports Server (NTRS)

Jacobson, Steven R.

2010-01-01

Loss of control is the leading cause of jet fatalities worldwide. Aside from their frequency of occurrence, accidents resulting from loss of aircraft control seize the public s attention by yielding a large number of fatalities in a single event. In response to the rising threat to aviation safety, the NASA Aviation Safety Program has conducted a study of the loss of control problem. This study gathered four types of information pertaining to loss of control accidents: (1) statistical data; (2) individual accident reports that cite loss of control as a contributing factor; (3) previous meta-analyses of loss of control accidents; and (4) inputs solicited from aircraft manufacturers, air carriers, researchers, and other industry stakeholders. Using these information resources, the study team identified the causal factors that were cited in the greatest number of loss of control accidents, and which were emphasized most by industry stakeholders. This report describes the study approach, the key causal factors for aircraft loss of control, and recommended mitigation strategies to make near-term impacts, mid-term impacts, and Next Generation Air Transportation System impacts on the loss of control accident statistics

Two examples of industrial applications of shock physics research

NASA Astrophysics Data System (ADS)

Sanai, Mohsen

1996-05-01

An in-depth understanding of shock physics phenomena has led to many industrial applications. Two recent applications discussed in this paper are a method for assessing explosion safety in industrial plants and a bomb-resistant luggage container for widebody aircraft. Our explosion safety assessment is based on frequent use of computer simulation of postulated accidents to model in detail the detonation of energetic materials, the formation and propagation of the resulting airblast, and the projection of fragments of known material and mass. Using a general load-damage analysis technique referred to as the pressure-impulse (PI) method, we have developed a PC-based computer algorithm that includes a continually expanding library of PI load and damage curves, which can predict and graphically display common structural damage modes and the response of humans to postulated explosion accidents. A second commercial application of shock physics discussed here is a bomb-resistant luggage container for widebody aircraft that can protect the aircraft from a terrorist bomb hidden inside the luggage. This hardened luggage container (HLC) relies on blast management and debris containment provided by a flexible flow-through blanket woven from threads made with a strong lightweight material, such as Spectra or Kevlar. This mitigation blanket forms a continuous and seamless shell around the sides of the luggage container that are parallel to the aircraft axis, leaving the two ends of the container unprotected. When an explosion occurs, the mitigation blanket expands into a nearly circular shell that contains the flying debris while directing the flow into the adjacent containers. The HLC concept has been demonstrated through full-scale experiments conducted at SRI. We believe that these two examples represent a broad class of potential industrial hazard applications of the experimental, analytical, and computational tools possessed by the shock physics community.

Integrating Cloud-Computing-Specific Model into Aircraft Design

NASA Astrophysics Data System (ADS)

Zhimin, Tian; Qi, Lin; Guangwen, Yang

Cloud Computing is becoming increasingly relevant, as it will enable companies involved in spreading this technology to open the door to Web 3.0. In the paper, the new categories of services introduced will slowly replace many types of computational resources currently used. In this perspective, grid computing, the basic element for the large scale supply of cloud services, will play a fundamental role in defining how those services will be provided. The paper tries to integrate cloud computing specific model into aircraft design. This work has acquired good results in sharing licenses of large scale and expensive software, such as CFD (Computational Fluid Dynamics), UG, CATIA, and so on.

Examination of the costs, benefits and enery conservation aspects of the NASA aircraft fuel conservation technology program

NASA Technical Reports Server (NTRS)

1975-01-01

The costs and benefits of the NASA Aircraft Fuel Conservation Technology Program are discussed. Consideration is given to a present worth analysis of the planned program expenditures, an examination of the fuel savings to be obtained by the year 2005 and the worth of this fuel savings relative to the investment required, a comparison of the program funding with that planned by other Federal agencies for energy conservation, an examination of the private industry aeronautical research and technology financial posture for the period FY 76 - FY 85, and an assessment of the potential impacts on air and noise pollution. To aid in this analysis, a computerized fleet mix forecasting model was developed. This model enables the estimation of fuel consumption and present worth of fuel expenditures for selected commerical aircraft fleet mix scenarios.

NASA's Research in Aircraft Vulnerability Mitigation

NASA Technical Reports Server (NTRS)

Allen, Cheryl L.

2005-01-01

Since its inception in 1958, the National Aeronautics and Space Administration s (NASA) role in civil aeronautics has been to develop high-risk, high-payoff technologies to meet critical national aviation challenges. Following the events of Sept. 11, 2001, NASA recognized that it now shared the responsibility for improving homeland security. The NASA Strategic Plan was modified to include requirements to enable a more secure air transportation system by investing in technologies and collaborating with other agencies, industry, and academia. NASA is conducting research to develop and advance innovative and commercially viable technologies that will reduce the vulnerability of aircraft to threats or hostile actions, and identify and inform users of potential vulnerabilities in a timely manner. Presented in this paper are research plans and preliminary status for mitigating the effects of damage due to direct attacks on civil transport aircraft. The NASA approach to mitigation includes: preventing loss of an aircraft due to a hit from man-portable air defense systems; developing fuel system technologies that prevent or minimize in-flight vulnerability to small arms or other projectiles; providing protection from electromagnetic energy attacks by detecting directed energy threats to aircraft and on/off-board systems; and minimizing the damage due to high-energy attacks (explosions and fire) by developing advanced lightweight, damage-resistant composites and structural concepts. An approach to preventing aircraft from being used as weapons of mass destruction will also be discussed.

V/STOL tilt rotor aircraft study. Volume 9: Piloted simulator evaluation of the Boeing Vertol model 222 tilt rotor aircraft

NASA Technical Reports Server (NTRS)

Rosenstein, H.; Mcveigh, M. A.; Mollenkof, P. A.

1973-01-01

The results of a real time piloted simulation to investigate the handling qualities and performance of a tilting rotor aircraft design are presented. The aerodynamic configuration of the aircraft is described. The procedures for conducting the simulator evaluation are reported. Pilot comments of the aircraft handling qualities under various simulated flight conditions are included. The time histories of selected pilot maneuvers are shown.

NASA's Role in Aeronautics: A Workshop. Volume 3: Transport aircraft

NASA Technical Reports Server (NTRS)

1981-01-01

Segments of the spectrum of research and development activities that clearly must be within the purview of NASA in order for U.S. transport aircraft manufacturing and operating industries to succeed and to continue to make important contributions to the nation's wellbeing were examined. National facilities and expertise; basic research, and the evolution of generic and vehicle class technologies were determined to be the areas in which NASA has an essential role in transport aircraft aeronautics.

A simple-source model of military jet aircraft noise

NASA Astrophysics Data System (ADS)

Morgan, Jessica; Gee, Kent L.; Neilsen, Tracianne; Wall, Alan T.

2010-10-01

The jet plumes produced by military jet aircraft radiate significant amounts of noise. A need to better understand the characteristics of the turbulence-induced aeroacoustic sources has motivated the present study. The purpose of the study is to develop a simple-source model of jet noise that can be compared to the measured data. The study is based off of acoustic data collected near a tied-down F-22 Raptor. The simplest model consisted of adjusting the origin of a monopole above a rigid planar reflector until the locations of the predicted and measured interference nulls matched. The model has developed into an extended Rayleigh distribution of partially correlated monopoles which fits the measured data from the F-22 significantly better. The results and basis for the model match the current prevailing theory that jet noise consists of both correlated and uncorrelated sources. In addition, this simple-source model conforms to the theory that the peak source location moves upstream with increasing frequency and lower engine conditions.

The lift-fan aircraft: Lessons learned

NASA Technical Reports Server (NTRS)

Deckert, Wallace H.

1995-01-01

This report summarizes the highlights and results of a workshop held at NASA Ames Research Center in October 1992. The objective of the workshop was a thorough review of the lessons learned from past research on lift fans, and lift-fan aircraft, models, designs, and components. The scope included conceptual design studies, wind tunnel investigations, propulsion systems components, piloted simulation, flight of aircraft such as the SV-5A and SV-5B and a recent lift-fan aircraft development project. The report includes a brief summary of five technical presentations that addressed the subject The Lift-Fan Aircraft: Lessons Learned.

Influence of Transport on Two-Dimensional Model Simulation: 2. Stratospheric Aircraft Perturbations. 2; Stratospheric Aircraft Perturbations

NASA Technical Reports Server (NTRS)

Fleming, Eric L.; Jackman, Charles H.; Considine, David B.

1999-01-01

We have adopted the transport scenarios used in Part 1 to examine the sensitivity of stratospheric aircraft perturbations to transport changes in our 2-D model. Changes to the strength of the residual circulation in the upper troposphere and stratosphere and changes to the lower stratospheric K(sub zz) had similar effects in that increasing the transport rates decreased the overall stratospheric residence time and reduced the magnitude of the negative perturbation response in total ozone. Increasing the stratospheric K(sub yy) increased the residence time and enhanced the global scale negative total ozone response. However, increasing K(sub yy) along with self-consistent increases in the corresponding planetary wave drive, which leads to a stronger residual circulation, more than compensates for the K(sub yy)-effect, and results in a significantly weaker perturbation response, relative to the base case, throughout the stratosphere. We found a relatively minor model perturbation response sensitivity to the magnitude of K(sub yy) in the tropical stratosphere, and only a very small sensitivity to the magnitude of the horizontal mixing across the tropopause and to the strength of the mesospheric gravity wave drag and diffusion. These transport simulations also revealed a generally strong correlation between passive NO(sub y) accumulation and age of air throughout the stratosphere, such that faster transport rates resulted in a younger mean age and a smaller NO(y) mass accumulation. However, specific variations in K(sub yy) and mesospheric gravity wave strength exhibited very little NO(sub y)-age correlation in the lower stratosphere, similar to 3-D model simulations performed in the recent NASA "Models and Measurements" II analysis. The base model transport, which gives the most favorable overall comparison with inert tracer observations, simulated a global/annual mean total ozone response of -0.59%, with only a slightly larger response in the northern compared to the

14 CFR 60.21 - Interim qualification of FSTDs for new aircraft types or models.

Code of Federal Regulations, 2011 CFR

2011-01-01

... aircraft, even though the aircraft manufacturer's aircraft data package is preliminary, if the sponsor...) Within twelve months of the release of the final aircraft data package by the aircraft manufacturer, but... apply for initial qualification in accordance with § 60.15 based on the final aircraft data package...

14 CFR 60.21 - Interim qualification of FSTDs for new aircraft types or models.

Code of Federal Regulations, 2014 CFR

2014-01-01

... aircraft, even though the aircraft manufacturer's aircraft data package is preliminary, if the sponsor...) Within twelve months of the release of the final aircraft data package by the aircraft manufacturer, but... apply for initial qualification in accordance with § 60.15 based on the final aircraft data package...

14 CFR 60.21 - Interim qualification of FSTDs for new aircraft types or models.

Code of Federal Regulations, 2010 CFR

2010-01-01

... aircraft, even though the aircraft manufacturer's aircraft data package is preliminary, if the sponsor...) Within twelve months of the release of the final aircraft data package by the aircraft manufacturer, but... apply for initial qualification in accordance with § 60.15 based on the final aircraft data package...

14 CFR 60.21 - Interim qualification of FSTDs for new aircraft types or models.

Code of Federal Regulations, 2013 CFR

2013-01-01

... aircraft, even though the aircraft manufacturer's aircraft data package is preliminary, if the sponsor...) Within twelve months of the release of the final aircraft data package by the aircraft manufacturer, but... apply for initial qualification in accordance with § 60.15 based on the final aircraft data package...

14 CFR 60.21 - Interim qualification of FSTDs for new aircraft types or models.

Code of Federal Regulations, 2012 CFR

2012-01-01

... aircraft, even though the aircraft manufacturer's aircraft data package is preliminary, if the sponsor...) Within twelve months of the release of the final aircraft data package by the aircraft manufacturer, but... apply for initial qualification in accordance with § 60.15 based on the final aircraft data package...

Recent Progress Towards Predicting Aircraft Ground Handling Performance

NASA Technical Reports Server (NTRS)

Yager, T. J.; White, E. J.

1981-01-01

The significant progress which has been achieved in development of aircraft ground handling simulation capability is reviewed and additional improvements in software modeling identified. The problem associated with providing necessary simulator input data for adequate modeling of aircraft tire/runway friction behavior is discussed and efforts to improve this complex model, and hence simulator fidelity, are described. Aircraft braking performance data obtained on several wet runway surfaces is compared to ground vehicle friction measurements and, by use of empirically derived methods, good agreement between actual and estimated aircraft braking friction from ground vehilce data is shown. The performance of a relatively new friction measuring device, the friction tester, showed great promise in providing data applicable to aircraft friction performance. Additional research efforts to improve methods of predicting tire friction performance are discussed including use of an instrumented tire test vehicle to expand the tire friction data bank and a study of surface texture measurement techniques.

Optimization in fractional aircraft ownership

NASA Astrophysics Data System (ADS)

Septiani, R. D.; Pasaribu, H. M.; Soewono, E.; Fayalita, R. A.

2012-05-01

Fractional Aircraft Ownership is a new concept in flight ownership management system where each individual or corporation may own a fraction of an aircraft. In this system, the owners have privilege to schedule their flight according to their needs. Fractional management companies (FMC) manages all aspects of aircraft operations, including utilization of FMC's aircraft in combination of outsourced aircrafts. This gives the owners the right to enjoy the benefits of private aviations. However, FMC may have complicated business requirements that neither commercial airlines nor charter airlines faces. Here, optimization models are constructed to minimize the number of aircrafts in order to maximize the profit and to minimize the daily operating cost. In this paper, three kinds of demand scenarios are made to represent different flight operations from different types of fractional owners. The problems are formulated as an optimization of profit and a daily operational cost to find the optimum flight assignments satisfying the weekly and daily demand respectively from the owners. Numerical results are obtained by Genetic Algorithm method.

14 CFR 91.1109 - Aircraft maintenance: Inspection program.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Aircraft maintenance: Inspection program... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... conduct of inspections for the particular make and model aircraft, including necessary tests and checks...

14 CFR 91.1109 - Aircraft maintenance: Inspection program.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Aircraft maintenance: Inspection program... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... conduct of inspections for the particular make and model aircraft, including necessary tests and checks...

14 CFR 91.1109 - Aircraft maintenance: Inspection program.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Aircraft maintenance: Inspection program... Ownership Operations Program Management § 91.1109 Aircraft maintenance: Inspection program. Each program... conduct of inspections for the particular make and model aircraft, including necessary tests and checks...

Technological change and productivity growth in the air transport industry

NASA Technical Reports Server (NTRS)

Rosenberg, N.; Thompson, A.; Belsley, S. E.

1978-01-01

The progress of the civil air transport industry in the United States was examined in the light of a proposal of Enos who, after examining the growth of the petroleum industry, divided that phenomenon into two phases, the alpha and the beta; that is, the invention, first development and production, and the improvement phase. The civil air transport industry developed along similar lines with the technological progress coming in waves; each wave encompassing several new technological advances while retaining the best of the old ones. At the same time the productivity of the transport aircraft as expressed by the product of the aircraft velocity and the passenger capacity increased sufficiently to allow the direct operating cost in cents per passenger mile to continually decrease with each successive aircraft development.

Flight testing a V/STOL aircraft to identify a full-envelope aerodynamic model

NASA Technical Reports Server (NTRS)

Mcnally, B. David; Bach, Ralph E., Jr.

1988-01-01

Flight-test techniques are being used to generate a data base for identification of a full-envelope aerodynamic model of a V/STOL fighter aircraft, the YAV-8B Harrier. The flight envelope to be modeled includes hover, transition to conventional flight and back to hover, STOL operation, and normal cruise. Standard V/STOL procedures such as vertical takeoff and landings, and short takeoff and landings are used to gather data in the powered-lift flight regime. Long (3 to 5 min) maneuvers which include a variety of input types are used to obtain large-amplitude control and response excitations. The aircraft is under continuous radar tracking; a laser tracker is used for V/STOL operations near the ground. Tracking data are used with state-estimation techniques to check data consistency and to derive unmeasured variables, for example, angular accelerations. A propulsion model of the YAV-8B's engine and reaction control system is used to isolate aerodynamic forces and moments for model identification. Representative V/STOL flight data are presented. The processing of a typical short takeoff and slow landing maneuver is illustrated.

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

The History of the XV-15 Tilt Rotor Research Aircraft: From Concept to Flight

NASA Technical Reports Server (NTRS)

Maisel, Martin D.; Giulianetti, Demo J.; Dugan, Daniel C.

2000-01-01

This monograph is a testament to the efforts of many people overcoming multiple technical challenges encountered while developing the XV-15 tilt rotor research aircraft. The Ames involvement with the tilt rotor aircraft began in 1957 with investigations of the performance and dynamic behavior of the Bell XV-3 tilt rotor aircraft. At that time, Ames Research Center was known as the Ames Aeronautical Laboratory of the National Advisory Committee for Aeronautics (NACA). As we approach the new millennium, and after more than 40 years of effort and the successful completion of our initial goals, it is appropriate to reflect on the technical accomplishments and consider the future applications of this unique aircraft class, the tilt rotor. The talented engineers, technicians, managers, and leaders at Ames have worked hard with their counterparts in the U.S. rotorcraft industry to overcome technology barriers and to make the military and civil tilt rotor aircraft safer, environmentally acceptable, and more efficient. The tilt rotor aircraft combines the advantages of vertical takeoff and landing capabilities, inherent to the helicopter, with the forward speed and range of a fixed wing turboprop airplane. Our studies have shown that this new vehicle type can provide the aviation transportation industry with the flexibility for highspeed, long-range flight, coupled with runway-independent operations, thus having a significant potential to relieve airport congestion. We see the tilt rotor aircraft as an element of the solution to this growing air transport problem.

Aircraft Piston Engine Exhaust Emission Symposium

NASA Technical Reports Server (NTRS)

1976-01-01

A 2-day symposium on the reduction of exhaust emissions from aircraft piston engines was held on September 14 and 15, 1976, at the Lewis Research Center in Cleveland, Ohio. Papers were presented by both government organizations and the general aviation industry on the status of government contracts, emission measurement problems, data reduction procedures, flight testing, and emission reduction techniques.

Payload Technologies for Remotely Piloted Aircraft

NASA Technical Reports Server (NTRS)

Wegener, Steve

2000-01-01

Matching the capabilities of Remotely Piloted Aircraft (RPA) to the needs of users defines the direction of future investment. These user needs and advances in payload capabilities are driving the evolution of a commercially viable RPA aerospace industry. New perspectives are needed to realize the potential of RPAs. Advances in payload technologies and the impact on RPA design and operations will be explored.

Payload Technologies For Remotely Piloted Aircraft

NASA Technical Reports Server (NTRS)

Wegener, Steve; Condon, Estelle (Technical Monitor)

2001-01-01

Matching the capabilities of Remotely Piloted Aircraft (RPA) to the needs of users defines the direction of future investment. These user needs and advances in payload capabilities are driving the evolution of a commercially viable RPA aerospace industry. New perspectives are needed to realize the potential of RPAs. Advances in payload technologies and the impact on RPA design and operations will be explored.

NAIRAS aircraft radiation model development, dose climatology, and initial validation.

PubMed

Mertens, Christopher J; Meier, Matthias M; Brown, Steven; Norman, Ryan B; Xu, Xiaojing

2013-10-01

[1] The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles, including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which fall within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs, where the radiation dose level is low. Nevertheless, analysis

NAIRAS aircraft radiation model development, dose climatology, and initial validation

NASA Astrophysics Data System (ADS)

Mertens, Christopher J.; Meier, Matthias M.; Brown, Steven; Norman, Ryan B.; Xu, Xiaojing

2013-10-01

The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles, including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which fall within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs, where the radiation dose level is low. Nevertheless, analysis suggests

NAIRAS aircraft radiation model development, dose climatology, and initial validation

PubMed Central

Mertens, Christopher J; Meier, Matthias M; Brown, Steven; Norman, Ryan B; Xu, Xiaojing

2013-01-01

[1] The Nowcast of Atmospheric Ionizing Radiation for Aviation Safety (NAIRAS) is a real-time, global, physics-based model used to assess radiation exposure to commercial aircrews and passengers. The model is a free-running physics-based model in the sense that there are no adjustment factors applied to nudge the model into agreement with measurements. The model predicts dosimetric quantities in the atmosphere from both galactic cosmic rays (GCR) and solar energetic particles, including the response of the geomagnetic field to interplanetary dynamical processes and its subsequent influence on atmospheric dose. The focus of this paper is on atmospheric GCR exposure during geomagnetically quiet conditions, with three main objectives. First, provide detailed descriptions of the NAIRAS GCR transport and dosimetry methodologies. Second, present a climatology of effective dose and ambient dose equivalent rates at typical commercial airline altitudes representative of solar cycle maximum and solar cycle minimum conditions and spanning the full range of geomagnetic cutoff rigidities. Third, conduct an initial validation of the NAIRAS model by comparing predictions of ambient dose equivalent rates with tabulated reference measurement data and recent aircraft radiation measurements taken in 2008 during the minimum between solar cycle 23 and solar cycle 24. By applying the criterion of the International Commission on Radiation Units and Measurements (ICRU) on acceptable levels of aircraft radiation dose uncertainty for ambient dose equivalent greater than or equal to an annual dose of 1 mSv, the NAIRAS model is within 25% of the measured data, which fall within the ICRU acceptable uncertainty limit of 30%. The NAIRAS model predictions of ambient dose equivalent rate are generally within 50% of the measured data for any single-point comparison. The largest differences occur at low latitudes and high cutoffs, where the radiation dose level is low. Nevertheless, analysis

Flight directors for STOl aircraft

NASA Technical Reports Server (NTRS)

Rabin, U. H.

1983-01-01

Flight director logic for flight path and airspeed control of a powered-lift STOL aircraft in the approach, transition, and landing configurations are developed. The methods for flight director design are investigated. The first method is based on the Optimal Control Model (OCM) of the pilot. The second method, proposed here, uses a fixed dynamic model of the pilot in a state space formulation similar to that of the OCM, and includes a pilot work-load metric. Several design examples are presented with various aircraft, sensor, and control configurations. These examples show the strong impact of throttle effectiveness on the performance and pilot work-load associated with manual control of powered-lift aircraft during approach. Improved performed and reduced pilot work-load can be achieved by using direct-lift-control to increase throttle effectiveness.

Coexistence Analysis of Civil Unmanned Aircraft Systems at Low Altitudes

NASA Astrophysics Data System (ADS)

Zhou, Yuzhe

2016-11-01

The requirement of unmanned aircraft systems in civil areas is growing. However, provisioning of flight efficiency and safety of unmanned aircraft has critical requirements on wireless communication spectrum resources. Current researches mainly focus on spectrum availability. In this paper, the unmanned aircraft system communication models, including the coverage model and data rate model, and two coexistence analysis procedures, i. e. the interference and noise ratio criterion and frequency-distance-direction criterion, are proposed to analyze spectrum requirements and interference results of the civil unmanned aircraft systems at low altitudes. In addition, explicit explanations are provided. The proposed coexistence analysis criteria are applied to assess unmanned aircraft systems' uplink and downlink interference performances and to support corresponding spectrum planning. Numerical results demonstrate that the proposed assessments and analysis procedures satisfy requirements of flexible spectrum accessing and safe coexistence among multiple unmanned aircraft systems.

The insertion of human dynamics models in the flight control loops of V/STOL research aircraft. Appendix 2: The optimal control model of a pilot in V/STOL aircraft control loops

NASA Technical Reports Server (NTRS)

Zipf, Mark E.

1989-01-01

An overview is presented of research work focussed on the design and insertion of classical models of human pilot dynamics within the flight control loops of V/STOL aircraft. The pilots were designed and configured for use in integrated control system research and design. The models of human behavior that were considered are: McRuer-Krendel (a single variable transfer function model); and Optimal Control Model (a multi-variable approach based on optimal control and stochastic estimation theory). These models attempt to predict human control response characteristics when confronted with compensatory tracking and state regulation tasks. An overview, mathematical description, and discussion of predictive limitations of the pilot models is presented. Design strategies and closed loop insertion configurations are introduced and considered for various flight control scenarios. Models of aircraft dynamics (both transfer function and state space based) are developed and discussed for their use in pilot design and application. Pilot design and insertion are illustrated for various flight control objectives. Results of pilot insertion within the control loops of two V/STOL research aricraft (Sikorski Black Hawk UH-60A, McDonnell Douglas Harrier II AV-8B) are presented and compared against actual pilot flight data. Conclusions are reached on the ability of the pilot models to adequately predict human behavior when confronted with similar control objectives.

NASA Glenn's Contributions to Aircraft Engine Noise Research

NASA Technical Reports Server (NTRS)

Huff, Dennis L.

2014-01-01

This presentation reviews engine noise research conducted at the NASA Glenn Research Center over the past 70 years. This report includes a historical perspective of the Center and the facilities used to conduct the research. Major noise research programs are highlighted to show their impact on industry and on the development of aircraft noise reduction technology. Noise reduction trends are discussed, and future aircraft concepts are presented. Since the 1960s, research results show that the average perceived noise level has been reduced by about 20 decibels (dB). Studies also show that, depending on the size of the airport, the aircraft fleet mix, and the actual growth in air travel, another 15 to 17 dB reduction will be required to achieve NASAs long-term goal of providing technologies to limit objectionable noise to the boundaries of an average airport.

Potential applications of advanced aircraft in developing countries

NASA Technical Reports Server (NTRS)

Maddalon, D. V.

1978-01-01

An investigation sponsored by NASA indicates that air transportation can play an important role in the economic progress of developing countries. By the turn of the century, the rapid economic growth now occurring in many developing countries should result in a major redistribution of the world's income. Some countries now classified as 'developing' will become 'developed' and are likely to become far more important to the world's civil aviation industry. Developing countries will be increasingly important buyers of conventional subsonic long-haul jet passenger aircraft but not to the point of significant influence on the design or technological content of future aircraft of this type. However, the technological content of more specialized aircraft may be influenced by developing country requirements and reflected in designs which fill a need concerning specialized missions, related to short-haul, low-density, rough runways, and natural resource development.

NASA Glenn's Contributions to Aircraft Engine Noise Research

NASA Technical Reports Server (NTRS)

Huff, Dennis L.

2013-01-01

This report reviews all engine noise research conducted at the NASA Glenn Research Center over the past 70 years. This report includes a historical perspective of the Center and the facilities used to conduct the research. Major noise research programs are highlighted to show their impact on industry and on the development of aircraft noise reduction technology. Noise reduction trends are discussed, and future aircraft concepts are presented. Since the 1960s, research results show that the average perceived noise level has been reduced by about 20 decibels (dB). Studies also show that, depending on the size of the airport, the aircraft fleet mix, and the actual growth in air travel, another 15 to 17 dB reduction will be required to achieve NASA's long-term goal of providing technologies to limit objectionable noise to the boundaries of an average airport.

A process for the quantification of aircraft noise and emissions interdependencies

NASA Astrophysics Data System (ADS)

de Luis, Jorge

The main purpose of this dissertation is to develop a process to improve actual policy-making procedures in terms of aviation environmental effects. This research work expands current practices with physics based publicly available models. The current method uses solely information provided by industry members, and this information is usually proprietary, and not physically intuitive. The process herein proposed provides information regarding the interdependencies between the environmental effects of aircraft. These interdependencies are also tied to the actual physical parameters of the aircraft and the engine, making it more intuitive for decision-makers to understand the impacts to the vehicle due to different policy scenarios. These scenarios involve the use of fleet analysis tools in which the existing aircraft are used to predict the environmental effects of imposing new stringency levels. The aircraft used are reduced to a series of coefficients that represent their performance, in terms of flight characteristics, fuel burn, noise, and emissions. These coefficients are then utilized to model flight operations and calculate what the environmental impacts of those aircraft are. If a particular aircraft does not meet the stringency to be analyzed, a technology response is applied to it, in order to meet that stringency. Depending on the level of reduction needed, this technology response can have an effect on the fuel burn characteristic of the aircraft. Another important point of the current stringency analysis process is that it does not take into account both noise and emissions concurrently, but instead, it considers them separately, one at a time. This assumes that the interdependencies between the two do not exists, which is not realistic. The latest stringency process delineated in 2004 imposed a 2% fuel burn penalty for any required improvements on NOx, no matter the type of aircraft or engine, assuming that no company had the ability to produce a

The Aircraft Industry

DTIC Science & Technology

2005-01-01

market segment. Manufacturers are putting considerable effort into creating new models and upgrading current products for the high-end corporate...market share. Both competitors have new products entering the market with the Airbus A380 due around 2006, and the Boeing 787 scheduled for service in...commonality on all systems and technologies. First production models are expected to be delivered in 2008. Initial operating capability (IOC) for the U.S

Computational fluid dynamics modeling of transport and deposition of pesticides in an aircraft cabin

PubMed Central

Isukapalli, Sastry S.; Mazumdar, Sagnik; George, Pradeep; Wei, Binnian; Jones, Byron; Weisel, Clifford P.

2015-01-01

Spraying of pesticides in aircraft cabins is required by some countries as part of a disinsection process to kill insects that pose a public health threat. However, public health concerns remain regarding exposures of cabin crew and passengers to pesticides in aircraft cabins. While large scale field measurements of pesticide residues and air concentrations in aircraft cabins scenarios are expensive and time consuming, Computational Fluid Dynamics (CFD) models provide an effective alternative for characterizing concentration distributions and exposures. This study involved CFD modeling of a twin-aisle 11 row cabin mockup with heated manikins, mimicking a part of a fully occupied Boeing 767 cabin. The model was applied to study the flow and deposition of pesticides under representative scenarios with different spraying patterns (sideways and overhead) and cabin air exchange rates (low and high). Corresponding spraying experiments were conducted in the cabin mockup, and pesticide deposition samples were collected at the manikin’s lap and seat top for a limited set of five seats. The CFD model performed well for scenarios corresponding to high air exchange rates, captured the concentration profiles for middle seats under low air exchange rates, and underestimated the concentrations at window seats under low air exchange rates. Additionally, both the CFD and experimental measurements showed no major variation in deposition characteristics between sideways and overhead spraying. The CFD model can estimate concentration fields and deposition profiles at very high resolutions, which can be used for characterizing the overall variability in air concentrations and surface loadings. Additionally, these model results can also provide a realistic range of surface and air concentrations of pesticides in the cabin that can be used to estimate potential exposures of cabin crew and passengers to these pesticides. PMID:25642134

Flexible aircraft dynamic modeling for dynamic analysis and control synthesis

NASA Technical Reports Server (NTRS)

Schmidt, David K.

1989-01-01

The linearization and simplification of a nonlinear, literal model for flexible aircraft is highlighted. Areas of model fidelity that are critical if the model is to be used for control system synthesis are developed and several simplification techniques that can deliver the necessary model fidelity are discussed. These techniques include both numerical and analytical approaches. An analytical approach, based on first-order sensitivity theory is shown to lead not only to excellent numerical results, but also to closed-form analytical expressions for key system dynamic properties such as the pole/zero factors of the vehicle transfer-function matrix. The analytical results are expressed in terms of vehicle mass properties, vibrational characteristics, and rigid-body and aeroelastic stability derivatives, thus leading to the underlying causes for critical dynamic characteristics.

Learning the Task Management Space of an Aircraft Approach Model

NASA Technical Reports Server (NTRS)

Krall, Joseph; Menzies, Tim; Davies, Misty

2014-01-01

Validating models of airspace operations is a particular challenge. These models are often aimed at finding and exploring safety violations, and aim to be accurate representations of real-world behavior. However, the rules governing the behavior are quite complex: nonlinear physics, operational modes, human behavior, and stochastic environmental concerns all determine the responses of the system. In this paper, we present a study on aircraft runway approaches as modeled in Georgia Tech's Work Models that Compute (WMC) simulation. We use a new learner, Genetic-Active Learning for Search-Based Software Engineering (GALE) to discover the Pareto frontiers defined by cognitive structures. These cognitive structures organize the prioritization and assignment of tasks of each pilot during approaches. We discuss the benefits of our approach, and also discuss future work necessary to enable uncertainty quantification.

Partners in Freedom: Contributions of the Langley Research Center to U.S. Military Aircraft of the 1990's

NASA Technical Reports Server (NTRS)

Chambers, Joseph R.

2000-01-01

Established in 1917 as the nation#s first civil aeronautics research laboratory under the National Advisory Commit-tee for Aeronautics (NACA), Langley was a small laboratory that solved the problems of flight for military and civil aviation. Throughout history, Langley has maintained a working partnership with the Department of Defense, U.S. industry, universities, and other government agencies to support the defense of the nation with research. During World War II, Langley directed virtually all of its workforce and facilities to research for military aircraft. Following the war, a balanced program of military and civil projects was undertaken. In some instances Langley research from one aircraft program helped solve a problem in another. At the conclusion of some programs, Langley obtained the research models for additional tests to learn more about previously unknown phenomena. The data also proved useful in later developmental programs. Many of the military aircraft in the U.S. inventory as of late 1999 were over 20 years old. Langley activities that contributed to the development of some of these aircraft began over 50 years prior. This publication documents the role, from early concept stages to problem solving for fleet aircraft, that Langley played in the military aircraft fleet of the United States for the 1990's.

Modeling of aircraft exhaust emissions and infrared spectra for remote measurement of nitrogen oxides

NASA Astrophysics Data System (ADS)

Beier, K.; Schreier, F.

1994-10-01

Infrared (IR) molecular spectroscopy is proposed to perform remote measurements of NOx concentrations in the exhaust plume and wake of aircraft. The computer model NIRATAM is applied to simulate the physical and chemical properties of the exhaust plume and to generate low resolution IR spectra and synthetical thermal images of the aircraft in its natural surroundings. High-resolution IR spectra of the plume, including atmospheric absorption and emission, are simulated using the molecular line-by-line radiation model FASCODE2. Simulated IR spectra of a Boeing 747-400 at cruising altitude for different axial and radial positions in the jet region of the exhaust plume are presented. A number of spectral lines of NO can be identified that can be discriminated from lines of other exhaust gases and the natural atmospheric background in the region around 5.2 µm. These lines can be used to determine NO concentration profiles in the plume. The possibility of measuring nitrogen dioxide NO2 is also discussed briefly, although measurements turn out to be substantially less likely than those of NO. This feasibility study compiles fundamental data for the optical and radiometric design of an airborne Fourier transform spectrometer and the preparation of in-flight measurements for monitoring of aircraft pollutants

Propulsion system mathematical model for a lift/cruise fan V/STOL aircraft

NASA Technical Reports Server (NTRS)

Cole, G. L.; Sellers, J. F.; Tinling, B. E.

1980-01-01

A propulsion system mathematical model is documented that allows calculation of internal engine parameters during transient operation. A non-realtime digital computer simulation of the model is presented. It is used to investigate thrust response and modulation requirements as well as the impact of duty cycle on engine life and design criteria. Comparison of simulation results with steady-state cycle deck calculations showed good agreement. The model was developed for a specific 3-fan subsonic V/STOL aircraft application, but it can be adapted for use with any similar lift/cruise V/STOL configuration.

Finite Element Analysis of Composite Aircraft Fuselage Frame

NASA Astrophysics Data System (ADS)

Dandekar, Aditya Milind

Composites have been introduced in aircraft industries, for their stronger, stiffer, and lighter properties than their metal-alloys counterparts. The general purpose of an aircraft is to transport commercial or military payload. Aircraft frames primarily maintains the shape of fuselage and prevent instability of the structure. Fuselage is similar as wing in construction which consist of longitudinal elements (longerons and stringers), transverse elements (frames and bulkheads) and its external skin. The fuselage is subjected to forces such as the wing reactions, landing gear reaction, empennage reaction, inertia forces subjected due to size and weight, internal pressure forces due to high altitude. Frames also ensure fail-safe design against skin crack propagation due to hoops stress. Ideal fuselage frames cross section is often circular ring shape with a frame cap of Z section. They are mainly made up of light alloy commonly used is aluminium alloys such as Al-2024, Al-7010, Al-7050, Al-7175. Aluminium alloys have good strength to density ratios in compression and bending of thin plate. A high strength to weight ratio of composite materials can result in a lighter aircraft structure or better safety factor. This research focuses on analysis of fuselage frame under dynamic load condition with change in material. Composites like carbon fibre reinforced plastics [CFRP] and glass fibre reinforced plastics [GFRP] are compared with traditional aluminium alloy Al-7075. The frame is subjected to impact test by dropping it at a velocity of 30 ft. / secs from a height of 86 inch from its centre of gravity. These parameters are considered in event of failure of landing gear, and an aircraft is subject to belly landing or gear-up landing. The shear flow is calculated due to impact force which acts in radial direction. The frame is analysed under static structural and explicit dynamic load conditions. Geometry is created in ANSYS Design Modeler. Analysis setup is created using

Vibration and aeroelastic analysis of highly flexible HALE aircraft

NASA Astrophysics Data System (ADS)

Chang, Chong-Seok

The highly flexible HALE (High Altitude Long Endurance) aircraft analysis methodology is of interest because early studies indicated that HALE aircraft might have different vibration and aeroelastic characteristics from those of conventional aircraft. Recently the computer code Nonlinear Aeroelastic Trim And Stability of HALE Aircraft (NATASHA) was developed under NASA sponsorship. NATASHA can predict the flight dynamics and aeroelastic behavior for HALE aircraft with a flying wing configuration. Further analysis improvements for NATASHA were required to extend its capability to the ground vibration test (GVT) environment and to both GVT and aeroelastic behavior of HALE aircraft with other configurations. First, the analysis methodology, based on geometrically exact fully intrinsic beam theory, was extended to treat other aircraft cofigurations. Conventional aircraft with flexible fuselage and tail can now be modeled by treating the aircraft as an assembly of beam elements. NATASHA is now applicable to any aircraft cofiguration that can be modeled this way. The intrinsic beam formulation, which is a fundamental structural modeling approach, is now capable of being applying to a structure consisting of multiple beams by relating the virtual displacements and rotations at points where two or more beam elements are connected to each other. Additional aspects are also considered in the analysis such as auxiliary elevator input in the horizontal tail and fuselage aerodynamics. Second, the modeling approach was extended to treat the GVT environment for HALE aircraft, which have highly flexible wings. GVT has its main purpose to provide modal characteristics for model validation. A bungee formulation was developed by the augmented Lagrangian method and coupled to the intrinsic beam formulation for the GVT modeling. After the coupling procedure, the whole formulation cannot be fully intrinsic because the geometric constraint by bungee cords makes the system statically

Modeling of the Mode S tracking system in support of aircraft safety research

NASA Technical Reports Server (NTRS)

Sorensen, J. A.; Goka, T.

1982-01-01

This report collects, documents, and models data relating the expected accuracies of tracking variables to be obtained from the FAA's Mode S Secondary Surveillance Radar system. The data include measured range and azimuth to the tracked aircraft plus the encoded altitude transmitted via the Mode S data link. A brief summary is made of the Mode S system status and its potential applications for aircraft safety improvement including accident analysis. FAA flight test results are presented demonstrating Mode S range and azimuth accuracy and error characteristics and comparing Mode S to the current ATCRBS radar tracking system. Data are also presented that describe the expected accuracy and error characteristics of encoded altitude. These data are used to formulate mathematical error models of the Mode S variables and encoded altitude. A brief analytical assessment is made of the real-time tracking accuracy available from using Mode S and how it could be improved with down-linked velocity.