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Sample records for advanced attack helicopter

  1. Stress analysis of advanced attack helicopter composite main rotor blade root end lug

    NASA Technical Reports Server (NTRS)

    Baker, D. J.

    1982-01-01

    Stress analysis of the Advanced Attack Helicopter (AAH) composite main rotor blade root end lug is described. The stress concentration factor determined from a finite element analysis is compared to an empirical value used in the lug design. The analysis and test data indicate that the stress concentration is primarily a function of configuration and independent of the range of material properties typical of Kevlar-49/epoxy and glass epoxy.

  2. Advanced Airfoils Boost Helicopter Performance

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Carson Helicopters Inc. licensed the Langley RC4 series of airfoils in 1993 to develop a replacement main rotor blade for their Sikorsky S-61 helicopters. The company's fleet of S-61 helicopters has been rebuilt to include Langley's patented airfoil design, and the helicopters are now able to carry heavier loads and fly faster and farther, and the main rotor blades have twice the previous service life. In aerial firefighting, the performance-boosting airfoils have helped the U.S. Department of Agriculture's Forest Service control the spread of wildfires. In 2003, Carson Helicopters signed a contract with Ducommun AeroStructures Inc., to manufacture the composite blades for Carson Helicopters to sell

  3. Advanced helicopter cockpit and control configurations for helicopter combat missions

    NASA Technical Reports Server (NTRS)

    Haworth, Loran A.; Atencio, Adolph, Jr.; Bivens, Courtland; Shively, Robert; Delgado, Daniel

    1987-01-01

    Two piloted simulations were conducted by the U.S. Army Aeroflightdynamics Directorate to evaluate workload and helicopter-handling qualities requirements for single pilot operation in a combat Nap-of-the-Earth environment. The single-pilot advanced cockpit engineering simulation (SPACES) investigations were performed on the NASA Ames Vertical Motion Simulator, using the Advanced Digital Optical Control System control laws and an advanced concepts glass cockpit. The first simulation (SPACES I) compared single pilot to dual crewmember operation for the same flight tasks to determine differences between dual and single ratings, and to discover which control laws enabled adequate single-pilot helicopter operation. The SPACES II simulation concentrated on single-pilot operations and use of control laws thought to be viable candidates for single pilot operations workload. Measures detected significant differences between single-pilot task segments. Control system configurations were task dependent, demonstrating a need for inflight reconfigurable control system to match the optimal control system with the required task.

  4. Sensor for measuring instantaneous angle of attack of helicopter blades

    NASA Technical Reports Server (NTRS)

    Barna, P. S.

    1980-01-01

    Systematic investigations were performed on a variety of probes to determine their potential for possible application as sensors attached to helicopter blades to measure both the instantaneous angle of attack as well as the dynamic head during actual flight operations. After some preliminary considerations a sensor of essentially spherical shape, about 30 mm in diameter, was designed. The sensor was provided with three pressure ports, and it housed two pressure transducers required for sensing the prevailing pressures acting outside on the surface. The sensors were subsequently tested in the laboratory under a variety of flow conditions to determine their aerodynamic characteristics. Two series of tests were performed: in the first series the sensor was fixed in space while exposed to steady uniform flow, while in the second series the sensor was made to oscillate, thus simulating the cyclic pitch change of the helicopter blades. While the cyclic pitch frequencies were of about the same magnitude as encountered in flight, the flow velocities during tests fell well below those experienced in a rotating blade. The tests showed that the sensors performed satisfactorily under low subsonic flow conditions with frequencies not exceeding five Hz.

  5. Attack helicopter (AH-1T) cockpit systems integration

    NASA Technical Reports Server (NTRS)

    Graf, V. A.

    1984-01-01

    This discussion summarizes the effort conducted by the BHTI Human Factors and Cockpit Arrangement group for a study and design of the integration of a cockpit control system for the AH 1T (TOW). The resulting design is a culmination of studies that were conducted using the existing configuration as a baseline and complementing it with new equipment and subsystems that fulfill the attack helicopter requirements for the foreseeable future. Of primary concern was the requirement to add a missile control system, with secondary considerations for improved NOE and night operations. In addition, growth capabilities for improved target acquisition, weapons delivery, and precise navigation was considered. Along with the addition of new equipment, the aircraft was assumed to have a central multiplex data bus system for information transfer throughout the aircraft and its subsystems.

  6. Technical Workshop: Advanced Helicopter Cockpit Design

    NASA Technical Reports Server (NTRS)

    Hemingway, J. C. (Editor); Callas, G. P. (Editor)

    1984-01-01

    Information processing demands on both civilian and military aircrews have increased enormously as rotorcraft have come to be used for adverse weather, day/night, and remote area missions. Applied psychology, engineering, or operational research for future helicopter cockpit design criteria were identified. Three areas were addressed: (1) operational requirements, (2) advanced avionics, and (3) man-system integration.

  7. The role of voice technology in advanced helicopter cockpits

    NASA Technical Reports Server (NTRS)

    Harper, H. P.

    1982-01-01

    The status of voice output and voice recognition technology in relation to helicopter cockpit applications is described. The maturing of this technology provides many opportunities for new approaches to crew workload reduction. The helicopter operating environment, potential application areas, and the impact on advanced cockpit design are discussed.

  8. Advanced Control System Increases Helicopter Safety

    NASA Technical Reports Server (NTRS)

    2008-01-01

    With support and funding from a Phase II NASA SBIR project from Ames Research Center, Hoh Aeronautics Inc. (HAI), of Lomita, California, produced HeliSAS, a low-cost, lightweight, attitude-command-attitude-hold stability augmentation system (SAS) for civil helicopters and unmanned aerial vehicles. HeliSAS proved itself in over 160 hours of flight testing and demonstrations in a Robinson R44 Raven helicopter, a commercial helicopter popular with news broadcasting and police operations. Chelton Flight Systems, of Boise, Idaho, negotiated with HAI to develop, market, and manufacture HeliSAS, now available as the Chelton HeliSAS Digital Helicopter Autopilot.

  9. Bell Helicopter Advanced Rotocraft Transmission (ART) program

    NASA Astrophysics Data System (ADS)

    Henry, Zachary S.

    1995-06-01

    Future rotorcraft transmissions require key emerging material and component technologies using advanced and innovative design practices in order to meet the requirements for a reduced weight to power ratio, a decreased noise level, and a substantially increased reliability. The specific goals for the future rotorcraft transmission when compared with a current state-of-the-art transmission (SOAT) are: (1) a 25 percent weight reduction; (2) a 10 dB reduction in the transmitted noise level; and (3) a system reliability of 5000 hours mean-time-between-removal (MTBR) for the transmission. This report summarizes the work conducted by Bell Helicopter Textron, Inc. to achieve these goals under the Advanced Rotorcraft Transmission (ART) program from 1988 to 1995. The reference aircraft selected by BHTI for the ART program was the Tactical Tiltrotor which is a 17,000 lb gross weight aircraft. A tradeoff study was conducted comparing the ART with a Selected SOAT. The results showed the ART to be 29 percent lighter and up to 13 dB quieter with a calculated MTBR in excess of 5000 hours. The results of the following high risk component and material tests are also presented: (1) sequential meshing high contact ratio planetary with cantilevered support posts; (2) thin dense chrome plated M50 NiL double row spherical roller planetary bearings; (3) reduced kinematic error and increased bending strength spiral bevel gears; (4) high temperature WE43 magnesium housing evaluation and coupon corrosion tests; (5) flexure fatigue tests of precision forged coupons simulating precision forged gear teeth; and (6) flexure fatigue tests of plasma carburized coupons simulating plasma carburized gear teeth.

  10. Bell Helicopter Advanced Rotocraft Transmission (ART) program

    NASA Technical Reports Server (NTRS)

    Henry, Zachary S.

    1995-01-01

    Future rotorcraft transmissions require key emerging material and component technologies using advanced and innovative design practices in order to meet the requirements for a reduced weight to power ratio, a decreased noise level, and a substantially increased reliability. The specific goals for the future rotorcraft transmission when compared with a current state-of-the-art transmission (SOAT) are: (1) a 25 percent weight reduction; (2) a 10 dB reduction in the transmitted noise level; and (3) a system reliability of 5000 hours mean-time-between-removal (MTBR) for the transmission. This report summarizes the work conducted by Bell Helicopter Textron, Inc. to achieve these goals under the Advanced Rotorcraft Transmission (ART) program from 1988 to 1995. The reference aircraft selected by BHTI for the ART program was the Tactical Tiltrotor which is a 17,000 lb gross weight aircraft. A tradeoff study was conducted comparing the ART with a Selected SOAT. The results showed the ART to be 29 percent lighter and up to 13 dB quieter with a calculated MTBR in excess of 5000 hours. The results of the following high risk component and material tests are also presented: (1) sequential meshing high contact ratio planetary with cantilevered support posts; (2) thin dense chrome plated M50 NiL double row spherical roller planetary bearings; (3) reduced kinematic error and increased bending strength spiral bevel gears; (4) high temperature WE43 magnesium housing evaluation and coupon corrosion tests; (5) flexure fatigue tests of precision forged coupons simulating precision forged gear teeth; and (6) flexure fatigue tests of plasma carburized coupons simulating plasma carburized gear teeth.

  11. Advanced automatic target recognition for police helicopter missions

    NASA Astrophysics Data System (ADS)

    Stahl, Christoph; Schoppmann, Paul

    2000-08-01

    The results of a case study about the application of an advanced method for automatic target recognition to infrared imagery taken from police helicopter missions are presented. The method consists of the following steps: preprocessing, classification, fusion, postprocessing and tracking, and combines the three paradigms image pyramids, neural networks and bayesian nets. The technology has been developed using a variety of different scenes typical for military aircraft missions. Infrared cameras have been in use for several years at the Bavarian police helicopter forces and are highly valuable for night missions. Several object classes like 'persons' or 'vehicles' are tested and the possible discrimination between persons and animals is shown. The analysis of complex scenes with hidden objects and clutter shows the potentials and limitations of automatic target recognition for real-world tasks. Several display concepts illustrate the achievable improvement of the situation awareness. The similarities and differences between various mission types concerning object variability, time constraints, consequences of false alarms, etc. are discussed. Typical police actions like searching for missing persons or runaway criminals illustrate the advantages of automatic target recognition. The results demonstrate the possible operational benefits for the helicopter crew. Future work will include performance evaluation issues and a system integration concept for the target platform.

  12. The effects of speech controls on performance in advanced helicopters in a double stimulation paradigm

    NASA Technical Reports Server (NTRS)

    Bortolussi, Michael R.; Vidulich, Michael A.

    1991-01-01

    The potential benefit of speech as a control modality has been investigated with mixed results. Earlier studies suggests that speech controls can reduce the potential of manual control overloads and improve time-sharing performance. However, these benefits were not without costs. Pilots reported higher workload levels associated with the use of speech controls. To further investigate these previous findings, an experiment was conducted in a simulation of an advanced single-pilot, scout/attack helicopter at NASA-Ames' ICAB (interchangeable cab) facility. Objective performance data suggested that speech control modality was effective in reducing interference of discrete, time-shared responses during continuous flight control activity. Subjective ratings, however, indicated that the speech control modality increased workload. Post-flight debriefing indicated that these results were mainly due to the increased effort to speak precisely to a less than perfect voice recognition system.

  13. Materials and structural aspects of advanced gas-turbine helicopter engines

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Acurio, J.

    1979-01-01

    The key to improved helicopter gas turbine engine performance lies in the development of advanced materials and advanced structural and design concepts. The modification of the low temperature components of helicopter engines (such as the inlet particle separator), the introduction of composites for use in the engine front frame, the development of advanced materials with increased use-temperature capability for the engine hot section, can result in improved performance and/or decreased engine maintenance cost. A major emphasis in helicopter engine design is the ability to design to meet a required lifetime. This, in turn, requires that the interrelated aspects of higher operating temperatures and pressures, cooling concepts, and environmental protection schemes be integrated into component design. The major material advances, coatings, and design life-prediction techniques pertinent to helicopter engines are reviewed; the current state-of-the-art is identified; and when appropriate, progress, problems, and future directions are assessed.

  14. Advanced Rotorcraft Transmission (ART) program-Boeing helicopters status report

    NASA Technical Reports Server (NTRS)

    Lenski, Joseph W., Jr.; Valco, Mark J.

    1991-01-01

    The Advanced Rotorcraft Transmission (ART) program is structured to incorporate key emerging material and component technologies into an advanced rotorcraft transmission with the intention of making significant improvements in the state of the art (SOA). Specific objectives of ART are: (1) Reduce transmission weight by 25 pct.; (2) Reduce transmission noise by 10 dB; and (3) Improve transmission life and reliability, while extending Mean Time Between Removal to 5000 hr. Boeing selected a transmission sized for the Tactical Tilt Rotor (TTR) aircraft which meets the Future Air Attack Vehicle (FAVV) requirements. Component development testing will be conducted to evaluate the high risk concepts prior to finalizing the advanced transmission configuration. The results of tradeoff studies and development test which were completed are summarized.

  15. Wind-tunnel evaluation of a 21-percent-scale powered model of a prototype advanced scout helicopter

    NASA Technical Reports Server (NTRS)

    Phelps, A. E., III; Berry, J. D.

    1985-01-01

    An exploratory wind tunnel investigation of a 21 percent scale powered model of a prototype advanced scout helicopter was conducted in the Langley 4 by 7 Meter Tunnel. The investigation was conducted to define the overall aerodynamic characteristics of the Army Helicopter Improvement Program (AHIP), to determine the effects of the rotor on the aerodynamic characteristics and to evaluate the effect of a mast mounted sight on the aircraft stability characteristics. Tests covered a range of thrust coefficients, advance ratios, angles of attack and angles of sideslip and were run for both rotor on and rotor off configurations. Results of the investigation showed that the prototype configuration was longitudinally unstable with angle of attack for all configurations tested. The instability was due to unfavorable interference effects between the horizontal tail and the wake shed from the engine pylon and rotor hub, which caused a loss of horizontal tail effectiveness. The addition of the mast mounted sight had little effect on the stability of the model, but it caused an alteration in the rotor lift distribution that resulted in substantial interference drag for the sight.

  16. A dissociation of objective and subjective workload measures in assessing the impact of speech controls in advanced helicopters

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.; Bortolussi, Michael R.

    1988-01-01

    Among the new technologies that are expected to aid helicopter designers are speech controls. Proponents suggest that speech controls could reduce the potential for manual control overloads and improve time-sharing performance in environments that have heavy demands for manual control. This was tested in a simulation of an advanced single-pilot, scout/attack helicopter. Objective performance indicated that the speech controls were effective in decreasing the interference of discrete responses during moments of heavy flight control activity. However, subjective ratings indicated that the use of speech controls required extra effort to speak precisely and to attend to feedback. Although the operational reliability of speech controls must be improved, the present results indicate that reliable speech controls could enhance the time-sharing efficiency of helicopter pilots. Furthermore, the results demonstrated the importance of using multiple assessment techniques to completely assess a task. Neither the objective nor the subjective measures alone provided complete information. It was the contrast between the measures that was most informative.

  17. Some recent advances in computational aerodynamics for helicopter applications

    NASA Technical Reports Server (NTRS)

    Mccroskey, W. J.; Baeder, J. D.

    1985-01-01

    The growing application of computational aerodynamics to nonlinear helicopter problems is outlined, with particular emphasis on several recent quasi-two-dimensional examples that used the thin-layer Navier-Stokes equations and an eddy-viscosity model to approximate turbulence. Rotor blade section characteristics can now be calculated accurately over a wide range of transonic flow conditions. However, a finite-difference simulation of the complete flow field about a helicopter in forward flight is not currently feasible, despite the impressive progress that is being made in both two and three dimensions. The principal limitations are today's computer speeds and memories, algorithm and solution methods, grid generation, vortex modeling, structural and aerodynamic coupling, and a shortage of engineers who are skilled in both computational fluid dynamics and helicopter aerodynamics and dynamics.

  18. A simulation investigation of scout/attack helicopter directional control requirements for hover and low-speed tasks

    NASA Technical Reports Server (NTRS)

    Bivens, Courtland C.; Guercio, Joseph G.

    1987-01-01

    A piloted simulator experiment was conducted to investigate directional axis handling qualities requirements for low speed and hover tasks performed by a Scout/Attack helicopter. Included were the directional characteristics of various candidate light helicopter family configurations. Also, the experiment focused on conventional single main/tail rotor configurations of the OH-58 series aircraft, where the first-order yaw-axis dynamic effects that contributed to the loss of tail rotor control were modeled. Five pilots flew 22 configurations under various wind conditions. Cooper-Harper handling quality ratings were used as the primary measure of merit of each configuration. The results of the experiment indicate that rotorcraft configurations with high directional gust sensitivity require greater minimum yaw damping to maintain satisfactory handling qualities during nap-of-the-Earth flying tasks. It was also determined that both yaw damping and control response are critical handling qualities parameters in performing the air-to-air target acquisition and tracking task. Finally, the lack of substantial yaw damping and larger values of gust sensitivity increased the possibility of loss of directional control at low airspeeds for the single main/tail rotor configurations.

  19. Integration, development, and qualification of the helmet-mounted sight and display on the Rooivalk Attack Helicopter

    NASA Astrophysics Data System (ADS)

    Mace, Timothy K.; Van Zyl, Petrus H.; Cross, Trevor

    2001-08-01

    The Rooivalk Attack Helicopter is designed and manufactured by Denel Aviation of South Africa, and in service with the South African Air Force. The Helmet Mounted Sight and Display (HMSD) hardware is manufactured by Sextant Avionique of France. The HMSD symbology is developed by Denel Aviation and is specific to the weapons and roles of the aircraft. The HMSD has visor projected NVG and PNVS images, and Flight and Weapon Symbology incorporating head slaved weapon aiming, helmet-to-helmet cueing, and helmet to main sight cueing. The NVG/PNVS image selection and main image controls are incorporated in the flight controls. The paper gives an overview of the aircraft visionic design and describes the integration process. The development of the displayed flight and weapon symbols is discussed. Aeronautical Design Standard 33E was chosen as a basis for the qualification process, and the development of the qualification criteria and the flight testing program are discussed.

  20. An in-flight investigation of symbology drive law improvements to an operational attack helicopter

    NASA Technical Reports Server (NTRS)

    Schroeder, Jeffery A.; Hindson, William S.; Eshow, Michelle M.

    1990-01-01

    A display drive-law design technique developed at Ames Research Center was applied to the design of the pilot-controlled symbol on a display used in an operational helicopter. A comparison of the newly designed laws and of one documented version of the operational laws was then performed using an in-flight simulation of the helicopter on the NASA/Army CH-47B. Flight-test results indicated that the Ames-developed drive laws were superior to this version of the operational drive laws in terms of task performance and pilot workload. Subsequent postflight-test information suggested that the documentation of the operational drive laws may have been incomplete or in error, even though pilot opinion had corroborated the correctness of the documented operational display in flight. Accordingly, based on additional information, another version of the operational display laws was developed and analyzed, although not flight tested. The revised operational version was compared analytically with the two versions tested in flight. This analysis corroborated that the Ames-developed laws would be superior to this revised version of the operational laws also. A conclusion is that close attention should be paid to the future specification, analysis, and documentation of displayed command-element dynamics, since they have an important effect on task performance and pilot workload.

  1. Tests of Full-Scale Helicopter Rotors at High Advancing Tip Mach Numbers and Advance Ratios

    NASA Technical Reports Server (NTRS)

    Biggers, James C.; McCloud, John L., III; Stroub, Robert H.

    2015-01-01

    As a continuation of the studies of reference 1, three full-scale helicopter rotors have been tested in the Ames Research Center 40- by SO-foot wind tunnel. All three of them were two-bladed, teetering rotors. One of the rotors incorporated the NACA 0012 airfoil section over the entire length of the blade. This rotor was tested at advance ratios up to 1.05. Both of the other rotors were tapered in thickness and incorporated leading-edge camber over the outer 20 percent of the blade radius. The larger of these rotors was tested at advancing tip Mach numbers up to 1.02. Data were obtained for a wide range of lift and propulsive force, and are presented without discussion.

  2. Research requirements to reduce empty weight of helicopters by use of advanced materials

    NASA Technical Reports Server (NTRS)

    Hoffstedt, D. J.

    1976-01-01

    Utilization of the new, lightweight, high-strength, aerospace structural-composite (filament/matrix) materials, when specifically designed into a new aircraft, promises reductions in structural empty weight of 12 percent at recurring costs competive with metals. A program of basic and applied research and demonstration is identified with the objective of advancing the state of the art to the point where civil helicopters are confidently designed, produced, certified, and marketed by 1985. A structural empty-weight reduction of 12 percent was shown to significantly reduce energy consumption in modern high-performance helicopters.

  3. Evaluation of speech recognizers for use in advanced combat helicopter crew station research and development

    NASA Technical Reports Server (NTRS)

    Simpson, Carol A.

    1990-01-01

    The U.S. Army Crew Station Research and Development Facility uses vintage 1984 speech recognizers. An evaluation was performed of newer off-the-shelf speech recognition devices to determine whether newer technology performance and capabilities are substantially better than that of the Army's current speech recognizers. The Phonetic Discrimination (PD-100) Test was used to compare recognizer performance in two ambient noise conditions: quiet office and helicopter noise. Test tokens were spoken by males and females and in isolated-word and connected-work mode. Better overall recognition accuracy was obtained from the newer recognizers. Recognizer capabilities needed to support the development of human factors design requirements for speech command systems in advanced combat helicopters are listed.

  4. Helicopter far-field acoustic levels as a function of reduced main-rotor advancing blade-tip Mach number

    NASA Technical Reports Server (NTRS)

    Mueller, Arnold W.; Smith, Charles D.; Lemasurier, Philip

    1990-01-01

    During the design of a helicopter, the weight, engine, rotor speed, and rotor geometry are given significant attention when considering the specific operations for which the helicopter will be used. However, the noise radiated from the helicopter and its relationship to the design variables is currently not well modeled with only a limited set of full-scale field test data to study. In general, limited field data have shown that reduced main-rotor advancing blade-tip Mach numbers result in reduced far-field noise levels. The status of a recent helicopter noise research project is reviewed. It is designed to provide flight experimental data which may be used to further understand helicopter main-rotor advancing blade-tip Mach number effects on far-field acoustic levels. Preliminary results are presented relative to tests conducted with a Sikorsky S-76A helicopter operating with both the rotor speed and the flight speed as the control variable. The rotor speed was operated within the range of 107 to 90 percent NR at nominal forward speeds of 35, 100, and 155 knots.

  5. Boeing Helicopters Advanced Rotorcraft Transmission (ART) program status

    NASA Technical Reports Server (NTRS)

    Lenski, Joseph W., Jr.

    1990-01-01

    A review is presented of a program structured to incorporate key emerging component and material technologies into an advanced rotorcraft transmission with the intent of making significant improvements in the state-of-the-art (SOA). The specific goals of this program include a reduction of transmission weight by 25 percent relative to SOA trends, a reduction of transmission noise by 10 dB relative to SOA, and improvment of transmission life and reliability while extending the mean time between removal to 5000 hours. Attention is given to comparisons and trade studies between transmission configurations, component development testing, improved bearing technology, and the aircraft selection process for the program.

  6. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Top view from gantry, showing helicopter in final position after sliding 23 feet from initial impact. Photographed at the Impact Dynamics Research Facility, building 1297.

  7. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Overall view of the nose landing gear (originally from Sikorsky S-76 helicopter). Photographed at the Impact Dynamics Research Facility, building 1297.

  8. Materials and structural aspects of advanced gas-turbine helicopter engines

    NASA Technical Reports Server (NTRS)

    Freche, J. C.; Acurio, J.

    1979-01-01

    Advances in materials, coatings, turbine cooling technology, structural and design concepts, and component-life prediction of helicopter gas-turbine-engine components are presented. Stationary parts including the inlet particle separator, the front frame, rotor tip seals, vanes and combustors and rotating components - compressor blades, disks, and turbine blades - are discussed. Advanced composite materials are considered for the front frame and compressor blades, prealloyed powder superalloys will increase strength and reduce costs of disks, the oxide dispersion strengthened alloys will have 100C higher use temperature in combustors and vanes than conventional superalloys, ceramics will provide the highest use temperature of 1400C for stator vanes and 1370C for turbine blades, and directionally solidified eutectics will afford up to 50C temperature advantage at turbine blade operating conditions. Coatings for surface protection at higher surface temperatures and design trends in turbine cooling technology are discussed. New analytical methods of life prediction such as strain gage partitioning for high temperature prediction, fatigue life, computerized prediction of oxidation resistance, and advanced techniques for estimating coating life are described.

  9. Aeroelastic behavior of composite helicopter rotor blades with advanced geometry tips

    SciTech Connect

    Friedmann, P.P.; Yuan, K.A.

    1995-12-31

    A new structural and aeroelastic model capable of representing the aeroelastic stability and response of composite helicopter rotor blades with advanced geometry tips is presented. Where it is understood that advanced geometry tips are blade tips having sweep, anhedral and taper in the outboard 10% segment of the blade. The blade is modeled by beam finite elements. A single element is used to represent the swept tip. The nonlinear equations of motion are derived using the Hamilton`s principle and are based on moderate deflection theory. Thus, the nonlinearities are of the geometric type. The important structural blade attributes captured by the model are arbitrary cross-sectional shape, general anisotropic material behavior, transverse shear and out-of-plane warping. The aerodynamic loads are based on quasi-steady Greenberg theory with reverse flow effects, using an implicit formulation. The nonlinear aeroelastic response of the blade is obtained from a fully coupled propulsive trim/aeroelastic response analysis. Aeroelastic stability is obtained from linearizing the equations of motion about the steady state response of the blade and using Floquet theory. Numerical results for the aeroelastic stability and response of a hingeless composite blade with two cell type cross section are presented, together with vibratory hub shears and moments. The influence of ply orientation and tip sweep is clearly illustrated by the results.

  10. Sikorski - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Roof instrument panel between pilot stations, right view. Photographed at the Impact Dynamics Research Facility, building 1297.

  11. Sikorski - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Roof instrument panel between pilot stations - left view. Photographed at the Impact Dynamics Research Facility, building 1297.

  12. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Sub-floor, inside view showing details of limited crushing. Photographed at the Impact Dynamics Research Facility, building 1297.

  13. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Left view of cockpit showing manikin head against panel. Photographed at the Impact Dynamics Research Facility, building 1297.

  14. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Right view of cabin showing troop seat fabric failure. Photographed at the Impact Dynamics Research Facility, building 1297.

  15. Helicopter human factors

    NASA Technical Reports Server (NTRS)

    Hart, Sandra G.

    1988-01-01

    The state-of-the-art helicopter and its pilot are examined using the tools of human-factors analysis. The significant role of human error in helicopter accidents is discussed; the history of human-factors research on helicopters is briefly traced; the typical flight tasks are described; and the noise, vibration, and temperature conditions typical of modern military helicopters are characterized. Also considered are helicopter controls, cockpit instruments and displays, and the impact of cockpit design on pilot workload. Particular attention is given to possible advanced-technology improvements, such as control stabilization and augmentation, FBW and fly-by-light systems, multifunction displays, night-vision goggles, pilot night-vision systems, night-vision displays with superimposed symbols, target acquisition and designation systems, and aural displays. Diagrams, drawings, and photographs are provided.

  16. Flap motion of helicopter rotors with novel, dynamic stall model

    NASA Astrophysics Data System (ADS)

    Han, Wei; Liu, Jie; Liu, Chun; Chen, Lei; Su, Xichao; Zhao, Peng

    2016-07-01

    In this paper, a nonlinear flapping equation for large inflow angles and flap angles is established by analyzing the aerodynamics of helicopter blade elements. In order to obtain a generalized flap equation, the Snel stall model was first applied to determine the lift coefficient of the helicopter rotor. A simulation experiment for specific airfoils was then conducted to verify the effectiveness of the Snel stall model as it applies to helicopters. Results show that the model requires no extraneous parameters compared to the traditional stall model and is highly accurate and practically applicable. Based on the model, the relationship between the flapping angle and the angle of attack was analyzed, as well as the advance ratio under the dynamic stall state.

  17. Flap-lag dynamics of hingeless helicopter blades at moderate and high advance ratios

    NASA Technical Reports Server (NTRS)

    Friedman, P.; Silverthorn, L. J.

    1974-01-01

    Equations for large amplitude coupled flaplag motion of a hingeless elastic helicopter blade in forward flight are derived. Only a torsionally rigid blade exicted by quasi-steady aerodynamic loads is considered. The effects of reversed flow together with some new terms due to forward flight are included. Using Galerkin's method the spatial dependence is eliminated and the equations are linearized about a suitable equilibrium position. The resulting system of equations is solved using multivariable Floquet-Liapunov theory, and the transition matrix at the end of the period is evaluated by two separate methods. Results illustrating the effects of forward flight and various important blade parameters on the stability boundaries are presented.

  18. Structural and aerodynamic loads and performance measurements of an SA349/2 helicopter with an advanced geometry rotor

    NASA Technical Reports Server (NTRS)

    Heffernan, Ruth M.; Gaubert, Michel

    1986-01-01

    A flight test program was conducted to obtain data from an upgraded Gazelle helicopter with an advanced geometry, three bladed rotor. Data were acquired on upper and lower surface chordwise blade pressure, blade bending and torsion moments, and fuselage structural loads. Results are presented from 16 individual flight conditions, including level flights ranging from 10 to 77 m/sec at 50 to 3000 m altitude, turning flights up to 2.0 g, and autorotation. Rotor aerodynamic data include information from 51 pressure transducers distributed chordwise at 75, 88, and 97% radial stations. Individual tranducer pressure coefficients and airfoil section lift and pitching moment coefficients are presented, as are steady state flight condition parameters and time dependence rotor loads. All dynamic data are presented as harmonic analysis coefficients.

  19. Investigating Flight with a Toy Helicopter

    NASA Astrophysics Data System (ADS)

    Liebl, Michael

    2010-10-01

    Flight fascinates people of all ages. Recent advances in battery technology have extended the capabilities of model airplanes and toy helicopters. For those who have never outgrown a childhood enthusiasm for the wonders of flight, it is possible to buy inexpensive, remotely controlled planes and helicopters. A toy helicopter offers an opportunity to investigate and study some basics of flight.

  20. Investigating Flight with a Toy Helicopter

    ERIC Educational Resources Information Center

    Liebl, Michael

    2010-01-01

    Flight fascinates people of all ages. Recent advances in battery technology have extended the capabilities of model airplanes and toy helicopters. For those who have never outgrown a childhood enthusiasm for the wonders of flight, it is possible to buy inexpensive, remotely controlled planes and helicopters. A toy helicopter offers an opportunity…

  1. Aeroelastic stability of coupled flap-lag motion of hingeless helicopter blades at arbitrary advance ratios

    NASA Technical Reports Server (NTRS)

    Friedmann, P.; Silverthorn, L. J.

    1974-01-01

    Equations for large amplitude coupled flap-lag motion of a hingeless elastic helicopter blade in forward flight are derived. Only a torsionally rigid blade excited by quasi-steady aerodynamic loads is considered. The effects of reversed flow together with some new terms due to radial flow are included. Using Galerkin's method the spatial dependence is eliminated and the equations are linearized about a suitable equilibrium position. The resulting system of homogeneous periodic equations is solved using multivariable Floquet-Liapunov theory, and the transition matrix at the end of the period is evaluated by two separate methods. Computational efficiency of the two numerical methods is compared. Results illustrating the effects of forward flight and various important blade parameters on the stability boundaries are presented.

  2. Advanced fighter technology integration (AFTI)/F-16 Automated Maneuvering Attack System final flight test results

    NASA Technical Reports Server (NTRS)

    Dowden, Donald J.; Bessette, Denis E.

    1987-01-01

    The AFTI F-16 Automated Maneuvering Attack System has undergone developmental and demonstration flight testing over a total of 347.3 flying hours in 237 sorties. The emphasis of this phase of the flight test program was on the development of automated guidance and control systems for air-to-air and air-to-ground weapons delivery, using a digital flight control system, dual avionics multiplex buses, an advanced FLIR sensor with laser ranger, integrated flight/fire-control software, advanced cockpit display and controls, and modified core Multinational Stage Improvement Program avionics.

  3. Sikorsky - (ACAP) - helicopter crash test

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Sikorsky - Advanced Composite Airframe Program (ACAP) - helicopter crash test. Sub-floor, inside view between station 175 and 143, showing limited crushing. Photographed at the Impact Dynamics Research Facility, building 1297.

  4. Prediction of Unsteady Blade Surface Pressures on an Advanced Propeller at an Angle of Attack

    NASA Technical Reports Server (NTRS)

    Nallasamy, M.; Groeneweg, J. F.

    1989-01-01

    The numerical solution of the unsteady, three-dimensional, Euler equations is considered in order to obtain the blade surface pressures of an advanced propeller at an angle of attack. The specific configuration considered is the SR7L propeller at cruise conditions with a 4.6 deg inflow angle corresponding to the plus 2 deg nacelle tilt of the Propeller Test Assessment (PTA) flight test condition. The results indicate nearly sinusoidal response of the blade loading, with angle of attack. For the first time, detailed variations of the chordwise loading as a function of azimuthal angle are presented. It is observed that the blade is lightly loaded for part of the revolution and shocks appear from hub to about 80 percent radial station for the highly loaded portion of the revolution.

  5. Advanced grid-stiffened composite shells for applications in heavy-lift helicopter rotor blade spars

    NASA Astrophysics Data System (ADS)

    Narayanan Nampy, Sreenivas

    Modern rotor blades are constructed using composite materials to exploit their superior structural performance compared to metals. Helicopter rotor blade spars are conventionally designed as monocoque structures. Blades of the proposed Heavy Lift Helicopter are envisioned to be as heavy as 800 lbs when designed using the monocoque spar design. A new and innovative design is proposed to replace the conventional spar designs with light weight grid-stiffened composite shell. Composite stiffened shells have been known to provide excellent strength to weight ratio and damage tolerance with an excellent potential to reduce weight. Conventional stringer--rib stiffened construction is not suitable for rotor blade spars since they are limited in generating high torsion stiffness that is required for aeroelastic stability of the rotor. As a result, off-axis (helical) stiffeners must be provided. This is a new design space where innovative modeling techniques are needed. The structural behavior of grid-stiffened structures under axial, bending, and torsion loads, typically experienced by rotor blades need to be accurately predicted. The overall objective of the present research is to develop and integrate the necessary design analysis tools to conduct a feasibility study in employing grid-stiffened shells for heavy-lift rotor blade spars. Upon evaluating the limitations in state-of-the-art analytical models in predicting the axial, bending, and torsion stiffness coefficients of grid and grid-stiffened structures, a new analytical model was developed. The new analytical model based on the smeared stiffness approach was developed employing the stiffness matrices of the constituent members of the grid structure such as an arch, helical, or straight beam representing circumferential, helical, and longitudinal stiffeners. This analysis has the capability to model various stiffening configurations such as angle-grid, ortho-grid, and general-grid. Analyses were performed using an

  6. Documenting helicopter operations from an energy standpoint

    NASA Technical Reports Server (NTRS)

    Davis, S. J.; Stepniewski, W. Z.

    1974-01-01

    Results are presented of a study of the relative and absolute energy consumption of helicopters, including limited comparisons with fixed-wing aircraft, and selected surface transportation vehicles. Additional comparisons were made to determine the level of reduction in energy consumption expected from the application of advanced technologies to the helicopter design and sizing process. It was found that improvements in helicopter consumption characteristics can be accomplished through the utilization of advanced technology to reduce drag, structures weight, and powerplant fuel consumption.

  7. Helicopter problems

    NASA Technical Reports Server (NTRS)

    Kussner, H G

    1937-01-01

    The present report deals with a number of the main problems requiring solution in the development of helicopters and concerning the lift, flying performance, stability, and drive. A complete solution is given for the stability of the helicopter with rigid blades and control surfaces. With a view to making a direct-lift propeller sufficient without the addition of auxiliary propellers, the "flapping drive" is assessed and its efficiency calculated.

  8. Tests Of Helicopter Control System

    NASA Technical Reports Server (NTRS)

    Hilbert, Kathryn B.; Lebacqz, J. Victor; Hindson, William S.

    1988-01-01

    Advanced control systems being developed for rotorcraft. Report discusses aspects of development of multivariable, explicit-model-following control system for CH-47B fly-by-wire helicopter. Project part of recent trend toward use of highly-augmented, high-gain flight-control systems to assist pilots of military helicopters in performance of demanding tasks and to improve handling qualities of aircraft.

  9. Development and validation of a blade-element mathematical model for the AH-64A Apache helicopter

    NASA Technical Reports Server (NTRS)

    Mansur, M. Hossein

    1995-01-01

    A high-fidelity blade-element mathematical model for the AH-64A Apache Advanced Attack Helicopter has been developed by the Aeroflightdynamics Directorate of the U.S. Army's Aviation and Troop Command (ATCOM) at Ames Research Center. The model is based on the McDonnell Douglas Helicopter Systems' (MDHS) Fly Real Time (FLYRT) model of the AH-64A (acquired under contract) which was modified in-house and augmented with a blade-element-type main-rotor module. This report describes, in detail, the development of the rotor module, and presents some results of an extensive validation effort.

  10. Dynamic analysis using superelements for a large helicopter model

    NASA Technical Reports Server (NTRS)

    Patel, M. P.; Shah, L. C.

    1978-01-01

    Using superelements (substructures), modal and frequency response analysis was performed for a large model of the Advanced Attack Helicopter developed for the U.S. Army. Whiffletree concept was employed so that the residual structure along with the various superelements could be represented as beam-like structures for economical and accurate dynamic analysis. A very large DMAP alter to the rigid format was developed so that the modal analysis, the frequency response, and the strain energy in each component could be computed in the same run.

  11. Boeing Helicopters Advanced Rotorcraft Transmission (ART) Program summary of component tests

    NASA Astrophysics Data System (ADS)

    Lenski, Joseph W., Jr.; Valco, Mark J.

    1992-07-01

    The principal objectives of the ART program are briefly reviewed, and the results of advanced technology component tests are summarized. The tests discussed include noise reduction by active cancellation, hybrid bidirectional tapered roller bearings, improved bearing life theory and friction tests, transmission lube study with hybrid bearings, and precision near-net-shape forged spur gears. Attention is also given to the study of high profile contact ratio noninvolute tooth form spur gears, parallel axis gear noise study, and surface modified titanium accessory spur gears.

  12. Application of a helicopter mathematical model to the Langley differential maneuvering simulator for use in a helicopter/fighter evasive maneuver study

    NASA Technical Reports Server (NTRS)

    Houck, J. A.; Ashworth, B. R.; Baker, D. R.

    1976-01-01

    A real time simulation study was conducted using a differential maneuvering simulator to determine and evaluate helicopter evasive maneuvers when attacked by fighter aircraft. A general helicopter mathematical model was modified to represent an H-53 helicopter. The helicopter model was compared to H-53 flight test data to determine any differences between the simulated and actual vehicles. The simulated helicopter was also subjectively validated by participating pilots. Two fighter mathematical models validated in previous studies were utilized for the attacking aircraft. The results of this simulation study have been verified in a flight test program conducted by the U. S. Air Force and were found to closely match the flight results.

  13. NASA helicopter transmission system technology program

    NASA Technical Reports Server (NTRS)

    Zaretsky, E. V.

    1983-01-01

    The purpose of the NASA Helicopter Transmission System Technology Program is to improve specific mechanical components and the technology for combining these into advanced drive systems to make helicopters more viable and cost competitive for commerical applications. The history, goals, and elements of the program are discussed.

  14. Helicopter Acoustics

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Exterior and interior noise problems are addressed both from the physics and engineering as well as the human factors point of view. The role of technology in closing the gap between what the customers and regulating agencies would like to have and what is available is explored. Noise regulation concepts, design, operations and testing for noise control, helicopter noise prediction, and research tools and measurements are among the topics covered.

  15. The Development of the CONDUIT Advanced Control System Design and Evaluation Interface with a Case Study Application to an Advanced Fly by Wire Helicopter Design

    NASA Technical Reports Server (NTRS)

    Colbourne, Jason

    1999-01-01

    This report details the development and use of CONDUIT (Control Designer's Unified Interface). CONDUIT is a design tool created at Ames Research Center for the purpose of evaluating and optimizing aircraft control systems against handling qualities. Three detailed design problems addressing the RASCAL UH-60A Black Hawk are included in this report to show the application of CONDUIT to helicopter control system design.

  16. Speech recognition in advanced rotorcraft - Using speech controls to reduce manual control overload

    NASA Technical Reports Server (NTRS)

    Vidulich, Michael A.; Bortolussi, Michael R.

    1988-01-01

    An experiment has been conducted to ascertain the usefulness of helicopter pilot speech controls and their effect on time-sharing performance, under the impetus of multiple-resource theories of attention which predict that time-sharing should be more efficient with mixed manual and speech controls than with all-manual ones. The test simulation involved an advanced, single-pilot scout/attack helicopter. Performance and subjective workload levels obtained supported the claimed utility of speech recognition-based controls; specifically, time-sharing performance was improved while preparing a data-burst transmission of information during helicopter hover.

  17. Materials for helicopter gears

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Some of the power train transmission gears in helicopter drive systems can become critical components as performance requirements are increased; accordingly, increasing attention must be paid to new alloys in order to obtain required performance reliability and survivability. Candidate advanced alloys, with improved high temperature properties, while increasing the resistance to scoring and scuffing, tend to have lower ductility and fracture toughness. An attempt is made to identify design materials, and process problems and requirements. In addition, it is recommended that the characterization of candidate steels be accelerated; preliminary investigation indicates that new alloys may provide improved capability against surface distress.

  18. Helicopter Human Factors

    NASA Technical Reports Server (NTRS)

    Hart, Sandra G.; Sridhar, Banavar (Technical Monitor)

    1995-01-01

    Even under optimal conditions, helicopter flight is a most demanding form of human-machine interaction, imposing continuous manual, visual, communications, and mental demands on pilots. It is made even more challenging by small margins for error created by the close proximity of terrain in NOE flight and missions flown at night and in low visibility. Although technology advances have satisfied some current and proposed requirements, hardware solutions alone are not sufficient to ensure acceptable system performance and pilot workload. However, human factors data needed to improve the design and use of helicopters lag behind advances in sensor, display, and control technology. Thus, it is difficult for designers to consider human capabilities and limitations when making design decisions. This results in costly accidents, design mistakes, unrealistic mission requirements, excessive training costs, and challenge human adaptability. NASA, in collaboration with DOD, industry, and academia, has initiated a program of research to develop scientific data bases and design principles to improve the pilot/vehicle interface, optimize training time and cost, and maintain pilot workload and system performance at an acceptable level. Work performed at Ames, and by other research laboratories, will be reviewed to summarize the most critical helicopter human factors problems and the results of research that has been performed to: (1) Quantify/model pilots use of visual cues for vehicle control; (2) Improve pilots' performance with helmet displays of thermal imagery and night vision goggles for situation awareness and vehicle control; (3) Model the processes by which pilots encode maps and compare them to the visual scene to develop perceptually and cognitively compatible electronic map formats; (4) Evaluate the use of spatially localized auditory displays for geographical orientation, target localization, radio frequency separation; (5) Develop and flight test control

  19. Iceproofing Helicopters

    NASA Technical Reports Server (NTRS)

    1977-01-01

    NASA aircraft-icing research has been applied to expand the utility of the big flying-crane helicopter built by the Sikorsky Aircraft Division of United Technologies in Stratford, Conn. Sikorsky wanted to adapt the Skycrane, used in both military and commercial service, to lift heavy external loads in areas where icing conditions occur; ice build-up around the engine air inlets caused the major problem. NASA-Lewis has a special wind tunnel for injecting super cooled water droplets into the wind thereby simulating a natural icing cloud and observing how ice builds up on various shaped surfaces. From Lewis, Sikorsky engineers obtained information which optimized the design of the inlet anti-ice system. The resulting design proved to be an effective anti-icing modification for the flying crane. Sikorsky is also using additional Lewis Icing Research Tunnel data in its development of a new VTOL (Vertical Take-Off and Landing) aircraft.

  20. Loads and Performance Data from a Wind-Tunnel Test of Generic Model Helicopter Rotor Blades

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Wilbur, Matthew L.

    2005-01-01

    An investigation was conducted in the NASA Langley Transonic Dynamics Tunnel to acquire data for use in assessing the ability of current and future comprehensive analyses to predict helicopter rotating-system and fixed-system vibratory loads. The investigation was conducted with a generic model helicopter rotor system using blades with rectangular planform, no built-in twist, uniform radial distribution of mass and stiffnesses, and a NACA 0012 airfoil section. Rotor performance data, as well as mean and vibratory components of blade bending and torsion moments, fixed-system forces and moments, and pitch link loads were obtained at advance ratios up to 0.35 for various combinations of rotor shaft angle-of-attack and collective pitch. The data are presented without analysis.

  1. Helicopters for the future

    NASA Technical Reports Server (NTRS)

    Ward, J. F.

    1984-01-01

    Technology needed to provide the basis for creating a widening rotary wing market include: well defined and proven design; reductions in noise, vibration, and fuel consumption; improvement of flying and ride quality; better safety; reliability; maintainability; and productivity. Unsteady transonic flow, yawed flow, dynamic stall, and blade vortex interaction are some of the problems faced by scientists and engineers in the helicopter industry with rotorcraft technology seen as an important development for future advanced high speed vehicle configurations. Such aircraft as the Boeing Vertol medium lift Model 360 composite aircraft, the Sikorsky Advancing Blade Concept (ABC) aircraft, the Bell Textron XV-15 Tilt Rotor Aircraft, and the X-wing rotor aircraft are discussed in detail. Even though rotorcraft technology has become an integral part of the military scene, the potential market for its civil applications has not been fully developed.

  2. Helicopter human factors research

    NASA Technical Reports Server (NTRS)

    Nagel, David C.; Hart, Sandra G.

    1988-01-01

    Helicopter flight is among the most demanding of all human-machine integrations. The inherent manual control complexities of rotorcraft are made even more challenging by the small margin for error created in certain operations, such as nap-of-the-Earth (NOE) flight, by the proximity of the terrain. Accident data recount numerous examples of unintended conflict between helicopters and terrain and attest to the perceptual and control difficulties associated with low altitude flight tasks. Ames Research Center, in cooperation with the U.S. Army Aeroflightdynamics Directorate, has initiated an ambitious research program aimed at increasing safety margins for both civilian and military rotorcraft operations. The program is broad, fundamental, and focused on the development of scientific understandings and technological countermeasures. Research being conducted in several areas is reviewed: workload assessment, prediction, and measure validation; development of advanced displays and effective pilot/automation interfaces; identification of visual cues necessary for low-level, low-visibility flight and modeling of visual flight-path control; and pilot training.

  3. Acoustic measurements of a full-scale coaxial helicopter

    NASA Technical Reports Server (NTRS)

    Mosher, M.; Peterson, R. L.

    1983-01-01

    Acoustic data were obtained during a full-scale test of the XH-59A Advancing Blade Concept (ABC) Technology Demonstrator in the NASA Ames 40- by 80-Foot Wind Tunnel. The XH-59A is a research helicopter with two coaxial rotors and hingeless blades. Performance, vibration, noise at various forward speeds, rotor lift coefficients, and rotor shaft angles of attack were investigated. In general, the noise level is shown to increase with rotor lift coefficient except under certain operating conditions where it is increased by significant impulsive blade/vortex interactions. The impulsivity appears to depend upon how the lift is distributed between the two rotors. The noise levels measured are shown to be slightly higher than on a modern conventional rotor tested in the same facility.

  4. Wind-tunnel evaluation of an advanced main-rotor blade design for a utility-class helicopter

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Mantay, Wayne R.; Wilbur, Matthew L.; Cramer, Robert G., Jr.; Singleton, Jeffrey D.

    1987-01-01

    An investigation was conducted in the Langley Transonic Dynamics Tunnel to evaluate differences between an existing utility-class main-rotor blade and an advanced-design main-rotor blade. The two rotor blade designs were compared with regard to rotor performance oscillatory pitch-link loads, and 4-per-rev vertical fixed-system loads. Tests were conducted in hover and over a range of simulated full-scale gross weights and density altitude conditions at advance ratios from 0.15 to 0.40. Results indicate that the advanced blade design offers performance improvements over the baseline blade in both hover and forward flight. Pitch-link oscillatory loads for the baseline rotor were more sensitive to the test conditions than those of the advanced rotor. The 4-per-rev vertical fixed-system load produced by the advanced blade was larger than that produced by the baseline blade at all test conditions.

  5. Helicopter Handling Qualities

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Helicopters are used by the military and civilian communities for a variety of tasks and must be capable of operating in poor weather conditions and at night. Accompanying extended helicopter operations is a significant increase in pilot workload and a need for better handling qualities. An overview of the status and problems in the development and specification of helicopter handling-qualities criteria is presented. Topics for future research efforts by government and industry are highlighted.

  6. Small Business Innovations (Helicopters)

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The amount of engine power required for a helicopter to hover is an important, but difficult, consideration in helicopter design. The EHPIC program model produces converged, freely distorted wake geometries that generate accurate analysis of wake-induced downwash, allowing good predictions of rotor thrust and power requirements. Continuum Dynamics, Inc., the Small Business Innovation Research (SBIR) company that developed EHPIC, also produces RotorCRAFT, a program for analysis of aerodynamic loading of helicopter blades in forward flight. Both helicopter codes have been licensed to commercial manufacturers.

  7. Helicopter transmission testing at NASA Lewis Research Center

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Coy, John J.

    1987-01-01

    The helicopter has evolved into a highly valuable air mobile vehicle for both military and civilian needs. The helicopter transmission requires advanced studies to develop a technology base for future rotorcraft advances. A joint helicopter transmission research program between the NASA Lewis Research Center and the U.S. Army Aviation Systems Command has existed since 1970. Program goals are to reduce weight and noise and to increase life and reliability. The current experimental activities at Lewis consist of full-scale helicopter transmission testing, a base effort in gearing technology, and a future effort in noise reduction technology. The experimental facilities at Lewis for helicopter transmission testing are described. A description of each of the rigs is presented along with some significant results and near-term plans.

  8. Cooperating attackers in neural cryptography.

    PubMed

    Shacham, Lanir N; Klein, Einat; Mislovaty, Rachel; Kanter, Ido; Kinzel, Wolfgang

    2004-06-01

    A successful attack strategy in neural cryptography is presented. The neural cryptosystem, based on synchronization of neural networks by mutual learning, has been recently shown to be secure under different attack strategies. The success of the advanced attacker presented here, called the "majority-flipping attacker," does not decay with the parameters of the model. This attacker's outstanding success is due to its using a group of attackers which cooperate throughout the synchronization process, unlike any other attack strategy known. An analytical description of this attack is also presented, and fits the results of simulations.

  9. 77 FR 5427 - Airworthiness Directives; Bell Helicopter Textron, Inc., Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-03

    ... FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska to the extent that it... Helicopter Textron, Inc., Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of... Bell Helicopter Textron, Inc., (Bell) Model 412 and 412EP helicopters. This proposal would...

  10. Research requirements to reduce civil helicopter life cycle cost

    NASA Technical Reports Server (NTRS)

    Blewitt, S. J.

    1978-01-01

    The problem of the high cost of helicopter development, production, operation, and maintenance is defined and the cost drivers are identified. Helicopter life cycle costs would decrease by about 17 percent if currently available technology were applied. With advanced technology, a reduction of about 30 percent in helicopter life cycle costs is projected. Technological and managerial deficiencies which contribute to high costs are examined, basic research and development projects which can reduce costs include methods for reduced fuel consumption; improved turbine engines; airframe and engine production methods; safety; rotor systems; and advanced transmission systems.

  11. Heart attack

    MedlinePlus

    ... infarction; Non-ST - elevation myocardial infarction; NSTEMI; CAD - heart attack; Coronary artery disease - heart attack ... made up of cholesterol and other cells. A heart attack may occur when: A tear in the ...

  12. Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors

    PubMed Central

    Kruyt, Jan W.; Quicazán-Rubio, Elsa M.; van Heijst, GertJan F.; Altshuler, Douglas L.; Lentink, David

    2014-01-01

    Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Previous quasi-steady experiments with a wing spinner set-up provide no support for this prediction. To test this more carefully, we compare the quasi-steady hover performance of 26 wings, from 12 hummingbird taxa. We spun the wings at angular velocities and angles of attack that are representative for every species and measured lift and torque more precisely. The power (aerodynamic torque × angular velocity) required to lift weight depends on aerodynamic efficacy, which is measured by the power factor. Our comparative analysis shows that AR has a modest influence on lift and drag forces, as reported earlier, but interspecific differences in power factor are large. During the downstroke, the power required to hover decreases for larger AR wings at the angles of attack at which hummingbirds flap their wings (p < 0.05). Quantitative flow visualization demonstrates that variation in hover power among hummingbird wings is driven by similar stable leading edge vortices that delay stall during the down- and upstroke. A side-by-side aerodynamic performance comparison of hummingbird wings and an advanced micro helicopter rotor shows that they are remarkably similar. PMID:25079868

  13. Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors.

    PubMed

    Kruyt, Jan W; Quicazán-Rubio, Elsa M; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

    2014-10-01

    Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Previous quasi-steady experiments with a wing spinner set-up provide no support for this prediction. To test this more carefully, we compare the quasi-steady hover performance of 26 wings, from 12 hummingbird taxa. We spun the wings at angular velocities and angles of attack that are representative for every species and measured lift and torque more precisely. The power (aerodynamic torque × angular velocity) required to lift weight depends on aerodynamic efficacy, which is measured by the power factor. Our comparative analysis shows that AR has a modest influence on lift and drag forces, as reported earlier, but interspecific differences in power factor are large. During the downstroke, the power required to hover decreases for larger AR wings at the angles of attack at which hummingbirds flap their wings (p < 0.05). Quantitative flow visualization demonstrates that variation in hover power among hummingbird wings is driven by similar stable leading edge vortices that delay stall during the down- and upstroke. A side-by-side aerodynamic performance comparison of hummingbird wings and an advanced micro helicopter rotor shows that they are remarkably similar.

  14. Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors.

    PubMed

    Kruyt, Jan W; Quicazán-Rubio, Elsa M; van Heijst, GertJan F; Altshuler, Douglas L; Lentink, David

    2014-10-01

    Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Previous quasi-steady experiments with a wing spinner set-up provide no support for this prediction. To test this more carefully, we compare the quasi-steady hover performance of 26 wings, from 12 hummingbird taxa. We spun the wings at angular velocities and angles of attack that are representative for every species and measured lift and torque more precisely. The power (aerodynamic torque × angular velocity) required to lift weight depends on aerodynamic efficacy, which is measured by the power factor. Our comparative analysis shows that AR has a modest influence on lift and drag forces, as reported earlier, but interspecific differences in power factor are large. During the downstroke, the power required to hover decreases for larger AR wings at the angles of attack at which hummingbirds flap their wings (p < 0.05). Quantitative flow visualization demonstrates that variation in hover power among hummingbird wings is driven by similar stable leading edge vortices that delay stall during the down- and upstroke. A side-by-side aerodynamic performance comparison of hummingbird wings and an advanced micro helicopter rotor shows that they are remarkably similar. PMID:25079868

  15. Fuzzy logic mode switching in helicopters

    NASA Technical Reports Server (NTRS)

    Sherman, Porter D.; Warburton, Frank W.

    1993-01-01

    The application of fuzzy logic to a wide range of control problems has been gaining momentum internationally, fueled by a concentrated Japanese effort. Advanced Research & Development within the Engineering Department at Sikorsky Aircraft undertook a fuzzy logic research effort designed to evaluate how effective fuzzy logic control might be in relation to helicopter operations. The mode switching module in the advanced flight control portion of Sikorsky's motion based simulator was identified as a good candidate problem because it was simple to understand and contained imprecise (fuzzy) decision criteria. The purpose of the switching module is to aid a helicopter pilot in entering and leaving coordinated turns while in flight. The criteria that determine the transitions between modes are imprecise and depend on the varied ranges of three flight conditions (i.e., simulated parameters): Commanded Rate, Duration, and Roll Attitude. The parameters were given fuzzy ranges and used as input variables to a fuzzy rulebase containing the knowledge of mode switching. The fuzzy control program was integrated into a real time interactive helicopter simulation tool. Optimization of the heading hold and turn coordination was accomplished by interactive pilot simulation testing of the handling quality performance of the helicopter dynamic model. The fuzzy logic code satisfied all the requirements of this candidate control problem.

  16. 78 FR 35773 - Airworthiness Directives; MD Helicopters, Inc. (MDHI), Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-14

    ...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... Directives; MD Helicopters, Inc. (MDHI), Helicopters AGENCY: Federal Aviation Administration, DOT. ACTION... the MDHI Model MD900 helicopters with certain main rotor blade (MRB) retention bolts (bolts)...

  17. Heart Attack

    MedlinePlus

    ... attack treatment works best when it's given right after symptoms occur. Prompt treatment of a heart attack can help prevent or limit damage to the heart and prevent sudden death. Call 9-1-1 Right Away A heart ...

  18. Modeling, State Estimation and Control of Unmanned Helicopters

    NASA Astrophysics Data System (ADS)

    Lau, Tak Kit

    error modeling and the filtering method for the sensor noise compensation. Moreover, we provide a fully automatic algorithm to tune our method. Finally, we evaluate our method on an instrumented gasoline helicopter. Experiments show that the technique enables the robust positioning of flying helicopters when no GNSS measurement is available. The design of an autopilot for an unmanned helicopter is made difficult by its nonlinear, coupled and non-minimum phase dynamics. Here, we consider a reinforcement learning approach to transfer motion skills from human to machine, and hence to achieve autonomous flight control. By making efficient use of a series of state-and-action pairs given by a human pilot, our algorithm bootstraps a parameterized control policy and learns to hover and follow trajectories after one manual flight. One key observation our algorithm is based on is that, although it is often difficult to retrieve the human pilots' hidden desiderata that formulate their state-feedback mechanisms in controlling the helicopters, it is possible to intercept the states of a helicopter and the actions by a human pilot and then to fit both into a model. We demonstrate the performance of our learning controller in experiments. The results described in this dissertation shed new and important light on the technology necessary to advance the current state of the unmanned helicopters. From a comprehensive dynamics modeling that addresses perplexing cross-couplings on the unmanned helicopters, to a robust state estimation against GNSS outage and a learn-from-scarce-sample control for an unmanned helicopter, we provide a starting point for the cultivation of the next-generation unmanned helicopters that can operate with the least possible human intervention.

  19. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Mardoian, George H.; Ezzo, Maureen B.

    1990-01-01

    An assessment is presented of ten composite tail rotor spars and four horizontal stabilizers exposed to the effects of in-flight commercial service for up to nine years to establish realistic environmental factors for use in future designs. This evaluation is supported by test results of helicopter components and panels which have been exposed to outdoor environmental effects since 1979. Full scale static and fatigue tests were conducted on graphite/epoxy and Kevlar/epoxy composite components removed from Sikorsky Model S-76 helicopters in commercial operations off the Gulf Coast of Louisiana. Small scale static and fatigue tests were conducted on coupons obtained from panels exposed to outdoor conditions in Stratford, CT and West Palm Beach, Florida. The panel materials and ply configurations were representative of the S-76 components. The results are discussed of moisture analyses and strength tests on both the S-76 components and composite panels after up to nine years of outdoor exposure. Full scale tests performed on the helicopter components did not disclose any significant reductions from the baseline strengths. The results increased confidence in the long term durability of advanced composite materials in helicopter structural applications.

  20. Helicopter simulator standards

    NASA Technical Reports Server (NTRS)

    Boothe, Edward M.

    1992-01-01

    The initial advisory circular was produced in 1984 (AC 120-XX). It was not finalized, however, because the FAR's for pilot certification did not recognize helicopter simulators and, therefore, permitted no credit for their use. That is being rectified, and, when the new rules are published, standards must be available for qualifying simulators. Because of the lack of a data base to support specification of these standards, the FAA must rely on the knowledge of experts in the simulator/training industry. A major aim of this workshop is to form a working group of these experts to produce a set of standards for helicopter training simulators.

  1. Summary highlights of the Advanced Rotorcraft Transmission (ART) program

    NASA Technical Reports Server (NTRS)

    Bill, Robert C.

    1992-01-01

    The NASA/U.S. Army Advanced Rotorcraft Transmission (ART) program is charged with the development and demonstration of lightweight, durable drivetrains for next-generation rotorcraft: (1) a Future Air Attack Vehicle for tactical ground-support and air-to-air missions, and (2) an Advanced Cargo Aircraft for heavy-lift field-support operations. Both tilt-rotor and more conventional helicopter configurations have been studied by the ART program. ART performance goals are sought through the use of advanced component materials and lubrication systems, transmission and geartrain configurations, and airframe/drivetrain integrations.

  2. Flight tests of IFR landing approach systems for helicopters

    NASA Technical Reports Server (NTRS)

    Bull, J. S.; Hegarty, D. M.; Peach, L. L.; Phillips, J. D.; Anderson, D. J.; Dugan, D. C.; Ross, V. L.

    1981-01-01

    Joint NASA/FAA helicopter flight tests were conducted to investigate airborne radar approaches (ARA) and microwave landing system (MLS) approaches. Flight-test results were utilized to prove NASA with a data base to be used as a performance measure for advanced guidance and navigation concepts, and to provide FAA with data for establishment of TERPS criteria. The first flight-test investigation consisted of helicopter IFR approaches to offshore oil rigs in the Gulf of Mexico, using weather/mapping radar, operational pilots, and a Bell 212 helicopter. The second flight-test investigation consisted of IFR MLS approaches at Crows Landing (near Ames Research Center), with a Bell UH-1H helicopter, using NASA, FAA, and operational industry pilots. Tests are described and results discussed.

  3. Helicopter low-speed yaw control

    NASA Technical Reports Server (NTRS)

    Wilson, John C. (Inventor); Kelley, Henry L. (Inventor); Crowell, Cynthia A. (Inventor)

    1993-01-01

    A system for improving yaw control at low speeds consists of one strake placed on the upper portion of the fuselage facing the retreating rotor blade and another strake placed on the lower portion of the fuselage facing the advancing rotor blade. These strakes spoil the airflow on the helicopter tail boom during hover, low speed flight, and right or left sidewards flight so that less side thrust is required from the tail rotor.

  4. 29 CFR 1926.551 - Helicopters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Helicopters. 1926.551 Section 1926.551 Labor Regulations....551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with any... removed. (g) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and...

  5. 29 CFR 1926.551 - Helicopters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Helicopters. 1926.551 Section 1926.551 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Helicopters, Hoists, Elevators, and Conveyors § 1926.551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with any...

  6. 29 CFR 1926.551 - Helicopters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Helicopters. 1926.551 Section 1926.551 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Helicopters, Hoists, Elevators, and Conveyors § 1926.551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with any...

  7. 29 CFR 1926.551 - Helicopters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Helicopters. 1926.551 Section 1926.551 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Helicopters, Hoists, Elevators, and Conveyors § 1926.551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with any...

  8. 29 CFR 1926.551 - Helicopters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Helicopters. 1926.551 Section 1926.551 Labor Regulations...) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Helicopters, Hoists, Elevators, and Conveyors § 1926.551 Helicopters. (a) Helicopter regulations. Helicopter cranes shall be expected to comply with any...

  9. SALAD helicopter integrated sensor

    SciTech Connect

    Soo Hoo, M.S.

    1988-08-01

    The theory and operation of an integrated acoustic and seismic sensor for use with the SALAD helicopter detection system is presented. This sensor incorporates a microphone, geophone, acoustic preamplifier, and tamper indicating features in a buryable, compact aluminum package. This sensor is intended for deployment within a pre-selected, controlled media.

  10. New passive helicopter detector

    SciTech Connect

    Elliott, G.R.

    1985-01-01

    Sandia has developed a new helicopter detector. The device relies on the correlation between the acoustic wave from the helicopter and the resulting coupled seismic wave. A significant feature of this approach is that the detector is completely passive; there is no radio frequency radiation. Intended for deployment as a perimeter sensor around a site, the unit offers a low nuisance/false alarm rate and a high probability of detection for a wide range of helicopters. Reliable detection occurs when the target is at high altitude and also very near the earth's surface. Detection ranges start at one kilometer for the small, four-place, civilian helicopter and approach five kilometers for heavier, military types. The system has two parts: a transducer package containing a microphone and a geophone and a digital processor. Development is underway for a model which will be AC powered and well suited to permanent facilities. A prototype unit using a lightweight, battery powered processor is being constructed for rapid-deployment applications. 6 figs.

  11. My experience with helicopters

    NASA Technical Reports Server (NTRS)

    Oemichen, Etienne

    1923-01-01

    The author recounts his experiments with helicopters. The object of his investigations was to remain stationary in the air for five minutes and to make a closed flight at low altitude. Some of the topics discussed include stabilization, horizontal flight, and directional control.

  12. The Focke Helicopter

    NASA Technical Reports Server (NTRS)

    Focke, H; Kruger, K B

    1938-01-01

    This report presents some of the problems concerning tests of helicopters, such as forced landings, controllability and stability, general safety, piloting maneuvers, performance, servicing, and the production of lift of a propeller. Test flights are described including a 67.67 mph flight by Hanna Reitsch.

  13. Research In Helicopter Noise

    NASA Technical Reports Server (NTRS)

    Yu, Yung H.; Schmitz, Frederic H.; Morse, Andrew H.

    1991-01-01

    Progress in aeroacoustical theory and experiments reviewed. Report summarizes continuing U.S. Army programs of research into causes of noise generated by helicopters. Topics of study include high-speed impulsive noise, blade/vortex-interaction noise, and low-frequency harmonic noise.

  14. Flow Environment Study Near the Empennage of a 15-Percent Scale Helicopter Model

    NASA Technical Reports Server (NTRS)

    Gorton, Susan Althoff; Berry, John D.; Hodges, W. Todd; Reis, Deane G.

    2000-01-01

    Development of advanced rotorcraft configurations has highlighted a need for high-quality experimental data to support the development of flexible and accurate analytical design tools. To provide this type of data, a test program was conducted in the Langley 14- by 22-Foot Subsonic Tunnel to measure the flow near the empennage of a 15-percent scale powered helicopter model with an operating tail fan. Three-component velocity profiles were measured with laser velocimetry (LV) one chord forward of the horizontal tail for four advance ratios to evaluate the effect of the rotor wake impingement on the horizontal tail angle of attack. These velocity data indicate the horizontal tail can experience unsteady angle of attack variations of over 30 degrees due to the rotor wake influence. The horizontal tail is most affected by the rotor wake above advance ratios of 0.10. Velocity measurements of the flow on the inlet side of the tail fan were made for a low-speed flight condition using conventional LV techniques. The velocity data show an accelerated flow near the tail fan duct, and vorticity calculations track the passage of main rotor wake vortices through the measurement plane.

  15. Inflow measurement made with a laser velocimeter on a helicopter model in forward flight. Volume 5: Tapered planform blades at an advance ratio of 0.23

    NASA Technical Reports Server (NTRS)

    Althoff, Susan L.; Elliott, Joe W.; Sailey, Richard H.

    1988-01-01

    An experimental investigation was conducted in the 14- by 22-Foot Subsonic tunnel at NASA Langley Research Center to measure the inflow into a scale model helicopter rotor in forward flight (mu sub inf = 0.23). The measurements were made with a two component Laser Velocimeter (LV) one chord above the plane formed by the path of the blade tips. A conditional sampling technique was employed to determine the position of the rotor at the time that each velocity measurement was made so that the azimuthal fluctuations in velocity could be determined. Measurements were made at a total of 168 separate locations in order to clearly define the inflow character. This data is presented without analysis. In order to increase the availability of the resulting data, both the mean and azimuthally dependenet values are included as part of this report on two 5.25 inch floppy disks in Microsoft Corporation MS-DOS format.

  16. Inflow Measurements Made with a Laser Velocimeter on a Helicopter Model in Forward Flight. Volume 1: Rectangular Planform Blades at an Advance Ration of 0.15

    NASA Technical Reports Server (NTRS)

    Elliott, Joe W.; Althoff, Susan L.; Sailey, Richard H.

    1988-01-01

    An experimental investigation was conducted in the 14- by 22-Foot Subsonic Tunnel at NASA Langley to measure the inflow into a scale model helicopter rotor in forward flight (microinf = 0.15). The measurements were made with a two component Laser Velocimeter (LV) one chord above the plane formed by the path of the rotor tips (tip path plane). A conditional sampling technique was employed to determine the azimuthal position of the rotor at the time each velocity measurement was made so that the azimuthal fluctuations in velocity could be determined. Measurements were made at a total of 147 separate locations in order to clearly define the inflow character. This data is presented without analysis. In order to increase the availability of the resulting data, both the mean and azimuthally dependent values are included as part of this report on two 5.25 inch floppy disks in Microsoft Corporation MS-DOS format.

  17. Inflow measurement made with a laser velocimeter on a helicopter model in forward flight. Volume 2: Rectangular planform blades at an advance ratio of 0.23

    NASA Technical Reports Server (NTRS)

    Elliott, Joe W.; Althoff, Susan L.; Sailey, Richard H.

    1988-01-01

    An experimental investigation was conducted in the 14- by 22-Foot Subsonic Tunnel at NASA Langley Research Center to measure the inflow into a scale model helicopter rotor in forward flight (mu sub infinity = 0.23). The measurements were made with a two-component Laser Velocimeter (LV) one chord above the plane formed by the path of the rotor tips (tip path plane). A conditional sampling technique was employed to determine the azimuthal position of the rotor at the time that each velocity measurement was made so that the azimuthal fluctuations in velocity could be determined. Measurements were made at a total of 180 separate locations in order to clearly define the inflow character. This data is presented without analysis.

  18. Inflow measurements made with a laser velocimeter on a helicopter model in forward flight. Volume 4: Tapered planform blades at an advance ratio of 0.15

    NASA Technical Reports Server (NTRS)

    Althoff, Susan L.; Elliott, Joe W.; Sailey, Richard H.

    1988-01-01

    An experimental investigation was conducted in the 14- by 22-Foot Subsonic Tunnel at NASA Langley Research Center to measure the inflow into the scale model helicopter rotor in forward flight (mu sub infinity = 0.15). The measurements were made with a two-component Laser Velocimeter (LV) one chord above the plane formed by the path of the rotor tips (tip path plane). A conditional sampling technique was employed to determine the position of the rotor at the time that each velocity measurement was made so that the azimuthal fluctuations in velocity could be determined. Measurements were made at a total of 146 separate locations in order to clearly define the inflow character. This data is presented herein without analysis. In order to increase the availability of the resulting data, both the mean and azimuthally dependent values are included as part of this report on two 5.25 inch floppy disks in MS-DOS format.

  19. Inflow measurement made with a laser velocimeter on a helicopter model in forward flight. Volume 3: Rectangular planform blades at an advance ratio of 0.30

    NASA Technical Reports Server (NTRS)

    Elliott, Joe W.; Althoff, Susan L.; Sailey, Richard H.

    1988-01-01

    An experimental investigation was conducted in the 14- by 22-Foot Subsonic Tunnel at NASA Langley Research Center to measure the inflow into a scale model helicopter rotor in forward flight (micron sub infinity = 0.30). The measurements were made with a two component Laser Velocimeter (LV) one chord above the plane formed by the path of the rotor tips (tip path plane). A conditional sampling technique was employed to determine the azimuthal position of the rotor at the time that each velocity measurement was made so that the azimuthal fluctuations in velocity could be determined. Measurements were made at a total of 180 separate locations in order to clearly define the inflow character. These data are presented without analysis.

  20. Heart Attack

    MedlinePlus

    ... a million people in the U.S. have a heart attack. About half of them die. Many people have permanent heart damage or die because they don't get ... It's important to know the symptoms of a heart attack and call 9-1-1 if someone ...

  1. Optimum Design of a Compound Helicopter

    NASA Technical Reports Server (NTRS)

    Yeo, Hyeonsoo; Johnson, Wayne

    2006-01-01

    A design and aeromechanics investigation was conducted for a 100,000-lb compound helicopter with a single main rotor, which is to cruise at 250 knots at 4000 ft/95 deg F condition. Performance, stability, and control analyses were conducted with the comprehensive rotorcraft analysis CAMRAD II. Wind tunnel test measurements of the performance of the H-34 and UH-1D rotors at high advance ratio were compared with calculations to assess the accuracy of the analysis for the design of a high speed helicopter. In general, good correlation was obtained when an increase of drag coefficients in the reverse flow region was implemented. An assessment of various design parameters (disk loading, blade loading, wing loading) on the performance of the compound helicopter was conducted. Lower wing loading (larger wing area) and higher blade loading (smaller blade chord) increased aircraft lift-to-drag ratio. However, disk loading has a small influence on aircraft lift-to-drag ratio. A rotor parametric study showed that most of the benefit of slowing the rotor occurred at the initial 20 to 30% reduction of the advancing blade tip Mach number. No stability issues were observed with the current design. Control derivatives did not change significantly with speed, but the did exhibit significant coupling.

  2. Helicopter trimming and tracking control using direct neural dynamic programming.

    PubMed

    Enns, R; Si, Jennie

    2003-01-01

    This paper advances a neural-network-based approximate dynamic programming control mechanism that can be applied to complex control problems such as helicopter flight control design. Based on direct neural dynamic programming (DNDP), an approximate dynamic programming methodology, the control system is tailored to learn to maneuver a helicopter. The paper consists of a comprehensive treatise of this DNDP-based tracking control framework and extensive simulation studies for an Apache helicopter. A trim network is developed and seamlessly integrated into the neural dynamic programming (NDP) controller as part of a baseline structure for controlling complex nonlinear systems such as a helicopter. Design robustness is addressed by performing simulations under various disturbance conditions. All designs are tested using FLYRT, a sophisticated industrial scale nonlinear validated model of the Apache helicopter. This is probably the first time that an approximate dynamic programming methodology has been systematically applied to, and evaluated on, a complex, continuous state, multiple-input multiple-output nonlinear system with uncertainty. Though illustrated for helicopters, the DNDP control system framework should be applicable to general purpose tracking control.

  3. Vehicle for civil helicopter ride quality research

    NASA Technical Reports Server (NTRS)

    Snyder, W. J.; Schlegel, R. G.

    1975-01-01

    A research aircraft for investigating the factors involved in civil helicopter operations was developed for NASA Langley Research Center. The aircraft is a reconfigured 17000 kg (36000 lb) military transport helicopter. The basic aircraft was reconfigured with advanced acoustic treatment, air-conditioning, and a 16-seat airline cabin. During the spring of 1975, the aircraft was flight tested to measure interior environment characteristics - noise and vibration - and was flown on 60 subjective flight missions with over 600 different subjects. Data flights established noise levels somewhat higher than expected, with a pure tone at 1400 Hz and vertical vibration levels between 0.07g and 0.17g. The noise and vibration levels were documented during subjective flight evaluations as being the primary source of discomfort. The aircraft will be utilized to document in detail the impact of various noise and vibration levels on passenger comfort during typical short-haul missions.

  4. Recent Langley helicopter acoustics contributions

    NASA Technical Reports Server (NTRS)

    Morgan, Homer G.; Pao, S. P.; Powell, C. A.

    1988-01-01

    The helicopter acoustics program at NASA Langley has included technology for elements of noise control ranging from sources of noise to receivers of noise. The scope of Langley contributions for about the last decade is discussed. Specifically, the resolution of two certification noise quantification issues by subjective acoustics research, the development status of the helicopter system noise prediction program ROTONET are reviewed and the highlights from research on blade rotational, broadband, and blade vortex interaction noise sources are presented. Finally, research contributions on helicopter cabin (or interior) noise control are presented. A bibliography of publications from the Langley helicopter acoustics program for the past 10 years is included.

  5. Stalling of Helicopter Blades

    NASA Technical Reports Server (NTRS)

    Gustafson, F B; Myers, G C , Jr

    1946-01-01

    Theoretical studies have predicted that operation of helicopter rotor beyond certain combinations of thrust, forward speed, and rotational speed might be prevented by rapidly increasing stalling of the retreating blade. The same studies also indicate that the efficiency of the rotor will increase until these limits are reached or closely approached, so that it is desirable to design helicopter rotors for operation close to the limits imposed by blade stalling. Inasmuch as the theoretical predictions of blade stalling involve numerous approximations and assumptions, an experimental investigation was needed to determine whether, in actual practice, the stall did occur and spread as predicted and to establish the amount of stalling that could be present without severe vibration or control difficulties being introduced. This report presents the results of such an investigation.

  6. Helicopter Visual Aid System

    NASA Technical Reports Server (NTRS)

    Baisley, R. L.

    1973-01-01

    The results of an evaluation of police helicopter effectiveness revealed a need for improved visual capability. A JPL program developed a method that would enhance visual observation capability for both day and night usage and demonstrated the feasibility of the adopted approach. This approach made use of remote pointable optics, a display screen, a slaved covert searchlight, and a coupled camera. The approach was proved feasible through field testing and by judgement against evaluation criteria.

  7. 78 FR 7645 - Airworthiness Directives; Bell Helicopter Textron, Inc., Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... landing gear, and subsequent loss of control of the helicopter. Comments After our NPRM (77 FR 5427... pertain to the NPRM (77 FR 5427, ] February 3, 2012) regarding Bell Model 412 and 412EP helicopters, and....gov . SUPPLEMENTARY INFORMATION: Discussion On February 3, 2012, at 77 FR 5427, the Federal...

  8. 77 FR 729 - Airworthiness Directives; Enstrom Helicopter Corporation Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-06

    ...; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February...-16900; AD 2011-26-10] RIN 2120-AA64 Airworthiness Directives; Enstrom Helicopter Corporation Helicopters...; request for comments. SUMMARY: We are adopting a new airworthiness directive (AD) for Enstrom...

  9. 78 FR 33770 - Airworthiness Directives; Bell Helicopter Textron, Inc. Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-05

    ... (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska to the extent that... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron, Inc. Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...

  10. 77 FR 30232 - Airworthiness Directives; Bell Helicopter Textron Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of...

  11. 77 FR 12991 - Airworthiness Directives; Robinson Helicopter Company Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-05

    ...). SUPPLEMENTARY INFORMATION: Airworthiness Directive 2011-12-10, Amendment 39-16717 (76 FR 35330, June 17, 2011...-074-AD; Amendment 39-16717; AD 2011-12-10] RIN 2120-AA64 Airworthiness Directives; Robinson Helicopter Company Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule;...

  12. 77 FR 42459 - Airworthiness Directives; MD Helicopters, Inc. (MDHI) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

    ..., and MD900 helicopters to require determining the cure date for each NOTAR fan blade tension-torsion... (expiration date). For the MDHI Model MD900 helicopters, AD 2006-18-01 (71 FR 51095, August 29, 2006) already... these same type designs. Related Service Information We have reviewed one MDHI service bulletin,...

  13. 77 FR 42421 - Airworthiness Directives; Bell Helicopter Textron Canada Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-19

    ... (76 FR 66609, October 27, 2011) for Bell Model 407 helicopters with a servo, part number (P/N) 206-076... issued AD 2011-15-51 (76 FR 66609, October 27, 2011), Transport Canada issued AD No. CF-2011-17R1, dated... helicopters. AD Requirements This AD retains the inspection requirements of AD 2011-15-51 (76 FR...

  14. Heart Attack

    MedlinePlus

    ... lower “bad” cholesterol (also called LDL, or low-density lipoprotein) levels and may help increase “good” cholesterol (also called HDL, or high-density lipoprotein). If you have had a heart attack, ...

  15. Helicopter simulation: Making it work

    NASA Technical Reports Server (NTRS)

    Payne, Barry

    1992-01-01

    The opportunities for improved training and checking by using helicopter simulators are greater than they are for airplane pilot training. Simulators permit the safe creation of training environments that are conducive to the development of pilot decision-making, situational awareness, and cockpit management. This paper defines specific attributes required in a simulator to meet a typical helicopter operator's training and checking objectives.

  16. Recent European Developments in Helicopters

    NASA Technical Reports Server (NTRS)

    1921-01-01

    Descriptions are given of two captured helicopters, one driven by electric power, the other by a gasoline engine. An account is given of flight tests of the gasoline powered vehicle. After 15 successful flight tests, the gasoline powered vehicle crashed due to the insufficient thrust. Also discussed here are the applications of helicopters for military observations, for meteorological work, and for carrying radio antennas.

  17. Helicopter Acoustics, part 2. [conferences

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Exterior and interior helicopter noise problems are addressed from the physics and engineering as well as the human factors point of view. Noise regulation concepts, human factors and criteria, rotor noise generation and control, design, operations and testing for noise control, helicopter noise prediction, and research tools and measurements are covered.

  18. Aeromechanics Analysis of a Compound Helicopter

    NASA Technical Reports Server (NTRS)

    Yeo, Hyeonsoo; Johnson, Wayne

    2006-01-01

    A design and aeromechanics investigation was conducted for a 100,000-lb compound helicopter with a single main rotor, which is to cruise at 250 knots at 4000 ft/95 deg F condition. Performance, stability, and control analyses were conducted with the comprehensive rotorcraft analysis CAMRAD II. Wind tunnel test measurements of the performance of the H-34 and UH-1D rotors at high advance ratio were compared with calculations to assess the accuracy of the analysis for the design of a high speed helicopter. In general, good correlation was obtained with the increase of drag coefficients in the reverse flow region. An assessment of various design parameters (disk loading, blade loading, wing loading) on the performance of the compound helicopter was made. Performance optimization was conducted to find the optimum twist, collective, tip speed, and taper using the comprehensive analysis. Blade twist was an important parameter on the aircraft performance and most of the benefit of slowing the rotor occurred at the initial 20 to 30% reduction of rotor tip speed. No stability issues were observed with the current design and the control derivatives did not change much with speed, but did exhibit significant coupling.

  19. 46 CFR 108.486 - Helicopter decks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST... Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks. At least two of the accesses to the helicopter landing deck must each have a fire hydrant on the...

  20. 14 CFR 93.103 - Helicopter operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Helicopter operations. 93.103 Section 93... Shore Helicopter Route § 93.103 Helicopter operations. (a) Unless otherwise authorized, each person piloting a helicopter along Long Island, New York's northern shoreline between the VPLYD waypoint...

  1. 46 CFR 108.653 - Helicopter facilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: “WARNING—HELICOPTER FUELING...

  2. 46 CFR 108.486 - Helicopter decks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST... Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks. At least two of the accesses to the helicopter landing deck must each have a fire hydrant on the...

  3. 46 CFR 108.486 - Helicopter decks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST... Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks. At least two of the accesses to the helicopter landing deck must each have a fire hydrant on the...

  4. 46 CFR 108.653 - Helicopter facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: “WARNING—HELICOPTER FUELING...

  5. 46 CFR 108.486 - Helicopter decks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST... Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks. At least two of the accesses to the helicopter landing deck must each have a fire hydrant on the...

  6. 46 CFR 108.653 - Helicopter facilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: “WARNING—HELICOPTER FUELING...

  7. 46 CFR 108.486 - Helicopter decks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter decks. 108.486 Section 108.486 Shipping COAST... Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.486 Helicopter decks. At least two of the accesses to the helicopter landing deck must each have a fire hydrant on the...

  8. 46 CFR 108.653 - Helicopter facilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: “WARNING—HELICOPTER FUELING...

  9. 46 CFR 108.653 - Helicopter facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter facilities. 108.653 Section 108.653 Shipping... EQUIPMENT Equipment Markings and Instructions § 108.653 Helicopter facilities. (a) Each helicopter fueling facility must be marked adjacent to the fueling hose storage: “WARNING—HELICOPTER FUELING...

  10. 14 CFR 93.103 - Helicopter operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Helicopter operations. 93.103 Section 93... Shore Helicopter Route § 93.103 Helicopter operations. (a) Unless otherwise authorized, each person piloting a helicopter along Long Island, New York's northern shoreline between the VPLYD waypoint...

  11. Helicopter discrimination apparatus for the murine radar

    DOEpatents

    Webb, Jr., John G.; Gray, Roger M.

    1977-01-01

    A helicopter discrimination apparatus for a radar utilizing doppler filtering to discriminate between a missile and ground clutter. The short duration of the doppler filter pulses which are emitted by helicopter rotor blades are processed to prevent false alarms, thus allowing the radar-protected helicopter to operate in formation with other helicopters while maintaining protection against infra-red-seeking missiles.

  12. Helicopter crashworthiness research program

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.; Boitnott, Richard L.; Carden, Huey D.

    1988-01-01

    Results are presented from the U.S. Army-Aerostructures Directorate/NASA-Langley Research Center joint research program on helicopter crashworthiness. Through the on-going research program an in-depth understanding was developed on the cause/effect relationships between material and architectural variables and the energy-absorption capability of composite material and structure. Composite materials were found to be efficient energy absorbers. Graphite/epoxy subfloor structures were more efficient energy absorbers than comparable structures fabricated from Kevlar or aluminum. An accurate method predicting the energy-absorption capability of beams was developed.

  13. Helicopter high gain control

    NASA Technical Reports Server (NTRS)

    Cunningham, T. B.; Nunn, E. C.

    1979-01-01

    High gain control is explored through a design study of the CH-47B helicopter. The plans are designed to obtain the maximum bandwidth possible given the hardware constraints. Controls are designed with modal control theory to specific bandwidths and closed loop mode shapes. Comparisons are made to an earlier complementary filter approach. Bandwidth improvement by removal of limitations is explored in order to establish hardware and mechanization options. Improvements in the pitch axis control system and in the rate gyro sensor noise characteristics in all axes are discussed. The use of rotor state feedback is assessed.

  14. World helicopter market study

    NASA Technical Reports Server (NTRS)

    Cleary, B.; Pearson, R. W.; Greenwood, S. W.; Kaplan, L.

    1978-01-01

    The extent of the threat to the US helicopter industry posed by a determined effort by foreign manufacturers, European companies in particular, to supply their own domestic markets and also to penetrate export markets, including the USA is assessed. Available data on US and world markets for civil and military uses are collated and presented in both graphic and tabular form showing the past history of production and markets and, where forecasts are available, anticipated future trends. The data are discussed on an item-by-item basis and inferences are drawn in as much depth as appears justified.

  15. Synthetic vision primary flight displays for helicopters

    NASA Astrophysics Data System (ADS)

    He, Gang; Feyereisen, Thea; Wilson, Blake

    2008-04-01

    This paper describes flight tests of Honeywell's synthetic vision primary flight display (SV PFD) system prototype for helicopter applications. The primary differences between fixed-wing and helicopter SV PFD and challenges of developing such an integrated system suitable for helicopter applications are discussed. The visual environment and flight symbology specifically developed for helicopter SV PFD are described. The flight test results and pilot evaluations of a prototype display system on-board Honeywell's ASTAR helicopter are discussed.

  16. At Issue: Helicopter Parents and Millennial Students, an Annotated Bibliography

    ERIC Educational Resources Information Center

    Pricer, Wayne F.

    2008-01-01

    Technological advances have made it easy for parents and children--many of them students--to communicate instantaneously. Devices and technologies such as cell phones, laptops, texting, and e-mail all enable various forms of instant communication. "Helicopter parents" are regarded as very overprotective and overly involved in the affairs of their…

  17. Helicopter technology benefits and needs. Volume 1: Summary

    NASA Technical Reports Server (NTRS)

    Zuk, J.; Adams, R. J.

    1980-01-01

    Present public service helicopter benefits and the potential benefits of an advanced public service rotorcraft (200 knots to 300 knots) are summarized. Past and future public service growth is quantified and assessed and needs, problem areas, and desired vehicle characteristics are defined. Research and technology recommendations are formulated and the costs and benefits of research options are assessed.

  18. The need for a dedicated public service helicopter design

    NASA Technical Reports Server (NTRS)

    Morrison, R.

    1984-01-01

    The need to provide the necessary funding to research, design and contract the building of an advanced technology rotorcraft that will meet the mission demands of public service (fire, police, paramedics and rescue) operators is discussed. Noise and cost factors, the greatest objections on the part of many police and public adminstrators are addressed. The growth of helicopter utilization in public service is documented.

  19. Important Scaling Parameters for Testing Model-Scale Helicopter Rotors

    NASA Technical Reports Server (NTRS)

    Singleton, Jeffrey D.; Yeager, William T., Jr.

    1998-01-01

    An investigation into the effects of aerodynamic and aeroelastic scaling parameters on model scale helicopter rotors has been conducted in the NASA Langley Transonic Dynamics Tunnel. The effect of varying Reynolds number, blade Lock number, and structural elasticity on rotor performance has been studied and the performance results are discussed herein for two different rotor blade sets at two rotor advance ratios. One set of rotor blades were rigid and the other set of blades were dynamically scaled to be representative of a main rotor design for a utility class helicopter. The investigation was con-densities permits the acquisition of data for several Reynolds and Lock number combinations.

  20. A pertinent solution of helicopter rotor flapping stability

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1972-01-01

    The stability of the flapping motion of a single blade of a helicopter rotor is examined using the techniques of perturbation theory. The equation of motion studied is linear, with periodic aerodynamic coefficients due to the forward speed of the rotor. Solutions are found for four cases: small and large advance ratio and small and large Lock number. The perturbation techniques appropriate to each case are discussed and illustrated in the course of the analysis. The application of perturbation techniques to other problems in rotor dynamics is discussed. It is concluded that perturbation theory is a powerful mathematical technique which should prove very useful in analyzing some of the problems of helicopter dynamics.

  1. Shark attack.

    PubMed

    Guidera, K J; Ogden, J A; Highhouse, K; Pugh, L; Beatty, E

    1991-01-01

    Shark attacks are rare but devastating. This case had major injuries that included an open femoral fracture, massive hemorrhage, sciatic nerve laceration, and significant skin and muscle damage. The patient required 15 operative procedures, extensive physical therapy, and orthotic assistance. A review of the literature pertaining to shark bites is included.

  2. Square tracking sensor for autonomous helicopter hover stabilization

    NASA Astrophysics Data System (ADS)

    Oertel, Carl-Henrik

    1995-06-01

    Sensors for synthetic vision are needed to extend the mission profiles of helicopters. A special task for various applications is the autonomous position hold of a helicopter above a ground fixed or moving target. As a proof of concept for a general synthetic vision solution a restricted machine vision system, which is capable of locating and tracking a special target, was developed by the Institute of Flight Mechanics of Deutsche Forschungsanstalt fur Luft- und Raumfahrt e.V. (i.e., German Aerospace Research Establishment). This sensor, which is specialized to detect and track a square, was integrated in the fly-by-wire helicopter ATTHeS (i.e., Advanced Technology Testing Helicopter System). An existing model following controller for the forward flight condition was adapted for the hover and low speed requirements of the flight vehicle. The special target, a black square with a length of one meter, was mounted on top of a car. Flight tests demonstrated the automatic stabilization of the helicopter above the moving car by synthetic vision.

  3. Helicopter noise regulations: An industry perspective

    NASA Technical Reports Server (NTRS)

    Wagner, R. A.

    1978-01-01

    A review of helicopter noise measurement programs and noise reduction/economic studies of FAA is given along with a critique of a study which addresses the economic impact of noise reduction on helicopter noise. Modification of several helicopters to reduce noise and demonstrate the economic impact of the application of the current state-of-the-art technology is discussed. Specific helicopters described include Boeing Vertol 347 Helicopter, Hughes OH-6 Helicopter, and Hughes 269C Helicopter. Other topics covered include: (1) noise trends and possible noise limits; (2) accuracy of helicopter noise prediction techniques; (3) limited change possibilities of derivatives; and (4) rotor impulsive noise. The unique operational capabilities of helicopters and the implications relative to noise regulations and certification are discussed.

  4. Lift capability prediction for helicopter rotor blade-numerical evaluation

    NASA Astrophysics Data System (ADS)

    Rotaru, Constantin; Cîrciu, Ionicǎ; Luculescu, Doru

    2016-06-01

    The main objective of this paper is to describe the key physical features for modelling the unsteady aerodynamic effects found on helicopter rotor blade operating under nominally attached flow conditions away from stall. The unsteady effects were considered as phase differences between the forcing function and the aerodynamic response, being functions of the reduced frequency, the Mach number and the mode forcing. For a helicopter rotor, the reduced frequency at any blade element can't be exactly calculated but a first order approximation for the reduced frequency gives useful information about the degree of unsteadiness. The sources of unsteady effects were decomposed into perturbations to the local angle of attack and velocity field. The numerical calculus and graphics were made in FLUENT and MAPLE soft environments. This mathematical model is applicable for aerodynamic design of wind turbine rotor blades, hybrid energy systems optimization and aeroelastic analysis.

  5. Advanced Rotorcraft Transmission (ART) program

    NASA Technical Reports Server (NTRS)

    Heath, Gregory F.; Bossler, Robert B., Jr.

    1993-01-01

    Work performed by the McDonnell Douglas Helicopter Company and Lucas Western, Inc. within the U.S. Army/NASA Advanced Rotorcraft Transmission (ART) Program is summarized. The design of a 5000 horsepower transmission for a next generation advanced attack helicopter is described. Government goals for the program were to define technology and detail design the ART to meet, as a minimum, a weight reduction of 25 percent, an internal noise reduction of 10 dB plus a mean-time-between-removal (MTBR) of 5000 hours compared to a state-of-the-art baseline transmission. The split-torque transmission developed using face gears achieved a 40 percent weight reduction, a 9.6 dB noise reduction and a 5270 hour MTBR in meeting or exceeding the above goals. Aircraft mission performance and cost improvements resulting from installation of the ART would include a 17 to 22 percent improvement in loss-exchange ratio during combat, a 22 percent improvement in mean-time-between-failure, a transmission acquisition cost savings of 23 percent of $165K, per unit, and an average transmission direct operating cost savings of 33 percent, or $24K per flight hour. Face gear tests performed successfully at NASA Lewis are summarized. Also, program results of advanced material tooth scoring tests, single tooth bending tests, Charpy impact energy tests, compact tension fracture toughness tests and tensile strength tests are summarized.

  6. Vertebral pain in helicopter pilots

    NASA Technical Reports Server (NTRS)

    Auffret, R.; Delahaye, R. P.; Metges, P. J.; VICENS

    1980-01-01

    Pathological forms of spinal pain engendered by piloting helicopters were clinically studied. Lumbalgia and pathology of the dorsal and cervical spine are discussed along with their clinical and radiological signs and origins.

  7. The evolution of helicopters

    NASA Astrophysics Data System (ADS)

    Chen, R.; Wen, C. Y.; Lorente, S.; Bejan, A.

    2016-07-01

    Here, we show that during their half-century history, helicopters have been evolving into geometrically similar architectures with surprisingly sharp correlations between dimensions, performance, and body size. For example, proportionalities emerge between body size, engine size, and the fuel load. Furthermore, the engine efficiency increases with the engine size, and the propeller radius is roughly the same as the length scale of the whole body. These trends are in accord with the constructal law, which accounts for the engine efficiency trend and the proportionality between "motor" size and body size in animals and vehicles. These body-size effects are qualitatively the same as those uncovered earlier for the evolution of aircraft. The present study adds to this theoretical body of research the evolutionary design of all technologies [A. Bejan, The Physics of Life: The Evolution of Everything (St. Martin's Press, New York, 2016)].

  8. 77 FR 52264 - Airworthiness Directives; Hughes Helicopters, Inc., and McDonnell Douglas Helicopter Systems...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-29

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... Directives; Hughes Helicopters, Inc., and McDonnell Douglas Helicopter Systems (Type Certificate Currently Held by MD Helicopters, Inc.) Helicopters AGENCY: Federal Aviation Administration (FAA), DOT....

  9. 77 FR 27116 - Safety Zone, Naval Helicopter Association Reunion Helicopter Demonstration, Elizabeth River...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-09

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone, Naval Helicopter Association Reunion... Norfolk, VA to support the Naval Helicopter Association Reunion Helicopter Demonstration. This action is necessary to provide for the safety of life on navigable waters during the Naval Helicopter...

  10. A mathematical model of a single main rotor helicopter for piloted simulation

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Tinling, B. E.; Decker, W. A.; Chen, R. T. N.

    1982-01-01

    A mathematical model, suitable for piloted simulation of the flying qualities of helicopters, is a nonlinear, total force and moment model of a single main rotor helicopter. The model has ten degrees of freedom: six rigid body, three rotor flapping, and the rotor rotational degrees of freedom. The rotor model assumes rigid blades with rotor forces and moments radially integrated and summed about the azimuth. The fuselage aerodynamic model uses a detailed representation over a nominal angle of attack and sideslip range of + or - 15 deg., as well as a simplified curve fit at large angles of attack or sideslip. Stabilizing surface aerodynamics are modeled with a lift curve slope between stall limits and a general curve fit for large angles of attack. A generalized stability and control augmentation system is described. Additional computer subroutines provide options for a simplified engine/governor model, atmospheric turbulence, and a linearized six degree of freedom dynamic model for stability and control analysis.

  11. Dynamic wake distortion model for helicopter maneuvering flight

    NASA Astrophysics Data System (ADS)

    Zhao, Jinggen

    A new rotor dynamic wake distortion model, which can be used to account for the rotor transient wake distortion effect on inflow across the rotor disk during helicopter maneuvering and transitional flight in both hover and forward flight conditions, is developed. The dynamic growths of the induced inflow perturbation across rotor disk during different transient maneuvers, such as a step pitch or roll rate, a step climb rate and a step change of advance ratio are investigated by using a dynamic vortex tube analysis. Based on the vortex tube results, a rotor dynamic wake distortion model, which is expressed in terms of a set of ordinary differential equations, with rotor longitudinal and lateral wake curvatures, wake skew and wake spacing as states, is developed. Also, both the Pitt-Peters dynamic inflow model and the Peters-He finite state inflow model for axial or forward flight are augmented to account for rotor dynamic wake distortion effect during helicopter maneuvering flight. To model the aerodynamic interaction among main rotor, tail rotor and empennage caused by rotor wake curvature effect during helicopter maneuvering flight, a reduced order model based on a vortex tube analysis is developed. Both the augmented Pitt-Peters dynamic inflow model and the augmented Peters-He finite state inflow model, combined with the developed dynamic wake distortion model, together with the interaction model are implemented in a generic helicopter simulation program of UH-60 Black Hawk helicopter and the simulated vehicle control responses in both time domain and frequency domain are compared with flight test data of a UH-60 Black Hawk helicopter in both hover and low speed forward flight conditions.

  12. A Comparison of Interactional Aerodynamics Methods for a Helicopter in Low Speed Flight

    NASA Technical Reports Server (NTRS)

    Berry, John D.; Letnikov, Victor; Bavykina, Irena; Chaffin, Mark S.

    1998-01-01

    Recent advances in computing subsonic flow have been applied to helicopter configurations with various degrees of success. This paper is a comparison of two specific methods applied to a particularly challenging regime of helicopter flight, very low speeds, where the interaction of the rotor wake and the fuselage are most significant. Comparisons are made between different methods of predicting the interactional aerodynamics associated with a simple generic helicopter configuration. These comparisons are made using fuselage pressure data from a Mach-scaled powered model helicopter with a rotor diameter of approximately 3 meters. The data shown are for an advance ratio of 0.05 with a thrust coefficient of 0.0066. The results of this comparison show that in this type of complex flow both analytical techniques have regions where they are more accurate in matching the experimental data.

  13. A new helicostat from SNIAS helicopter division

    NASA Technical Reports Server (NTRS)

    Morisset, J.

    1977-01-01

    The Helicostat was described as a helicopter in which the vehicle weight is nullified by two balloons arranged in a catamaran fashion. Development of such a vehicle is discussed, and various uses for these helicopters are summarized.

  14. Simulation model of the F/A-18 high angle-of-attack research vehicle utilized for the design of advanced control laws

    NASA Technical Reports Server (NTRS)

    Strickland, Mark E.; Bundick, W. Thomas; Messina, Michael D.; Hoffler, Keith D.; Carzoo, Susan W.; Yeager, Jessie C.; Beissner, Fred L., Jr.

    1996-01-01

    The 'f18harv' six degree-of-freedom nonlinear batch simulation used to support research in advanced control laws and flight dynamics issues as part of NASA's High Alpha Technology Program is described in this report. This simulation models an F/A-18 airplane modified to incorporate a multi-axis thrust-vectoring system for augmented pitch and yaw control power and actuated forebody strakes for enhanced aerodynamic yaw control power. The modified configuration is known as the High Alpha Research Vehicle (HARV). The 'f18harv' simulation was an outgrowth of the 'f18bas' simulation which modeled the basic F/A-18 with a preliminary version of a thrust-vectoring system designed for the HARV. The preliminary version consisted of two thrust-vectoring vanes per engine nozzle compared with the three vanes per engine actually employed on the F/A-18 HARV. The modeled flight envelope is extensive in that the aerodynamic database covers an angle-of-attack range of -10 degrees to +90 degrees, sideslip range of -20 degrees to +20 degrees, a Mach Number range between 0.0 and 2.0, and an altitude range between 0 and 60,000 feet.

  15. The Effects of Ambient Conditions on Helicopter Rotor Source Noise Modeling

    NASA Technical Reports Server (NTRS)

    Schmitz, Frederic H.; Greenwood, Eric

    2011-01-01

    A new physics-based method called Fundamental Rotorcraft Acoustic Modeling from Experiments (FRAME) is used to demonstrate the change in rotor harmonic noise of a helicopter operating at different ambient conditions. FRAME is based upon a non-dimensional representation of the governing acoustic and performance equations of a single rotor helicopter. Measured external noise is used together with parameter identification techniques to develop a model of helicopter external noise that is a hybrid between theory and experiment. The FRAME method is used to evaluate the main rotor harmonic noise of a Bell 206B3 helicopter operating at different altitudes. The variation with altitude of Blade-Vortex Interaction (BVI) noise, known to be a strong function of the helicopter s advance ratio, is dependent upon which definition of airspeed is flown by the pilot. If normal flight procedures are followed and indicated airspeed (IAS) is held constant, the true airspeed (TAS) of the helicopter increases with altitude. This causes an increase in advance ratio and a decrease in the speed of sound which results in large changes to BVI noise levels. Results also show that thickness noise on this helicopter becomes more intense at high altitudes where advancing tip Mach number increases because the speed of sound is decreasing and advance ratio increasing for the same indicated airspeed. These results suggest that existing measurement-based empirically derived helicopter rotor noise source models may give incorrect noise estimates when they are used at conditions where data were not measured and may need to be corrected for mission land-use planning purposes.

  16. Parasite-Drag Measurements of Five Helicopter Rotor Hubs

    NASA Technical Reports Server (NTRS)

    Churchill, Gary B.; Harrington, Robert D.

    1959-01-01

    An investigation has been conducted in the Langley full-scale tunnel to determine the parasite drag of five production-type helicopter rotor hubs. Some simple fairing arrangements were attempted in an effort to reduce the hub drag. The results indicate that, within the range of the tests, changes in angle of attack, hub rotational speed, and forward speed generally had only a small effect on the equivalent flat-plate area representing parasite drag. The drag coefficients of the basic hubs, based on projected hub frontal area, increased with hub area and varied from 0.5 to 0.76 for the hubs tested.

  17. 29 CFR 1910.183 - Helicopters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Helicopters. 1910.183 Section 1910.183 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage § 1910.183 Helicopters. (a) (b...) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and unloading areas. (h)...

  18. 29 CFR 1910.183 - Helicopters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 5 2013-07-01 2013-07-01 false Helicopters. 1910.183 Section 1910.183 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage § 1910.183 Helicopters. (a) (b...) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and unloading areas. (h)...

  19. 29 CFR 1910.183 - Helicopters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Helicopters. 1910.183 Section 1910.183 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage § 1910.183 Helicopters. (a) (b...) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and unloading areas. (h)...

  20. 29 CFR 1910.183 - Helicopters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Helicopters. 1910.183 Section 1910.183 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage § 1910.183 Helicopters. (a) (b...) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and unloading areas. (h)...

  1. 29 CFR 1910.183 - Helicopters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 5 2012-07-01 2012-07-01 false Helicopters. 1910.183 Section 1910.183 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Materials Handling and Storage § 1910.183 Helicopters. (a) (b...) Housekeeping. Good housekeeping shall be maintained in all helicopter loading and unloading areas. (h)...

  2. Velocity Measurements Near the Empennage of a SmallScale Helicopter Model

    NASA Technical Reports Server (NTRS)

    Gorton, Susan Althoff; Meyers, James F.; Berry, John D.

    1996-01-01

    A test program was conducted in the NASA Langley 14- by 22-Foot Subsonic Tunnel to measure the flow near the empennage of a small-scale powered helicopter model with an operating tail fan. Three-component velocity profiles were measured with Laser Velocimetry (LV) one chord forward of the horizontal tail for four advance ratios to evaluate the effect of the rotor wake impingement on the horizontal tail angle of attack. These velocity data indicate the horizontal tail can experience unsteady downwash angle variations of over 30 degrees due to the rotor wake influence. The horizontal tail is most affected by the rotor wake above advance ratios of 0.10. Velocity measurements of the flow on the inlet side of the fan were made for a low-speed flight condition using both conventional LV techniques and a promising, non-intrusive, global, three-component velocity measurement technique called Doppler Global Velocimetry (DGV). The velocity data show an accelerated flow near the fan duct, and vorticity calculations track the passage of main rotor wake vortices through the measurement plane. DGV shows promise as an evolving tool for rotor flowfield diagnostics.

  3. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Mardoian, George H.; Ezzo, Maureen B.

    1994-01-01

    This paper presents the results of a NASA funded contract and Sikorsky research and development programs to evaluate structural composite components in flight service on Sikorsky Model S-76 helicopters. Selected components were removed and tested at prescribed intervals over a nine year time frame. Four horizontal stabilizers and thirteen tail rotor spars were returned from commercial service in West Palm Beach, Florida and in the Gulf Coast region of Louisiana to determine the long term effects of operations in hot and humid climates on component performance. Concurrent with the flight component evaluation, panels of materials used in their fabrication were exposed to the environment in ground racks. Selected panels were tested annually to determine the effects of exposure on physical and mechanical properties. The results of 55,741 component flight hours and 911 months of field exposure are reported and compared with initial Federal Aviation Administration (FAA) certification data. The findings of this program have provided increased confidence in the long term durability of advanced composite materials used in helicopter structural applications.

  4. [Anaesthesia under unfavorable conditions - rescue helicopter].

    PubMed

    Knacke, Peer G; Gehring, Hartmut; Saur, Petra

    2011-03-01

    Rescue helicopters are used for emergency care and transport of emergency patients. The dimension of the cabin is clearly limited. A transport is carried out under spatial narrowness and high noise levels. Acoustic alarms or noises caused by the patient are hardly to be perceived, so that the view at optical alarms is necessary. Environmental conditions affect the concentration on the patient. Rearrangement maneuvers represent the most critical phases. Always the whole apparative monitoring and respirator must be in the field of view of the emergency doctor, drugs to the care must be handy to be quickly administered, the quantity of oxygen has to be observed. Infusions and option of airway management are ready to set in advance. Standardized work with the aid of algorithms and knowledge of treatment recommendations and guidelines help to prevent errors. To optimize the care of emergency patients, special training courses for the crew of rescue helicopters are offered. A training simulator to practice different scenarios and the establishment of a CIRS system are recommended. PMID:21400396

  5. Facial dog attack injuries.

    PubMed

    Lin, Wei; Patil, Pavan Manohar

    2015-02-01

    The exposed position of the face makes it vulnerable to dog bite injuries. This fact combined with the short stature of children makes them a high-risk group for such attacks. In contrast to wounds inflicted by assaults and accidents, dog bite wounds are deep puncture type wounds compounded by the presence of pathologic bacteria from the saliva of the attacking dog. This, combined with the presence of crushed, devitalized tissue makes these wounds highly susceptible to infection. Key to successful management of such wounds are meticulous cleansing of the wound, careful debridement, primary repair, appropriate antibiotic therapy, and rabies and tetanus immunization where indicated. This review presents an overview of the epidemiology, presentation, management of such emergencies, and the recent advances in the care of such patients. PMID:25829713

  6. Mobile terminal antennas for helicopters

    NASA Technical Reports Server (NTRS)

    Wu, Te-Kao; Farazian, K.; Golshan, N.; Divsalar, D.; Hinedi, S.; Woo, K.

    1993-01-01

    In this paper, the feasibility of using an L-band low gain antenna (LGA) as a mobile terminal antenna for helicopters is described. The objective is to select the lowest cost antenna system which can be easily mounted on a helicopter and capable of communicating with a geosynchronous satellite. To ensure that all the antenna options are being considered, the steerable high gain reflector and medium gain array antennas as well as LGA are studied and compared in an exhaustive survey. The high gain reflector antenna in L-band is usually very large in size and heavy in weight. In addition, a bulky and expensive tracking system is needed to steer the antenna beam to the satellite direction. The medium gain antennas (including mechanically and electronically steered arrays) are also more expensive and less reliable than an LGA due to the addition of a beam steering system to track the satellite. The omni-directional LGA is simple, reliable, and inexpensive. It is typically ten times smaller than the medium gain antenna. This makes the position, selection, and mounting on the helicopter relatively easier. Therefore, the LGA is selected as a mobile terminal antenna for helicopters. Among the many LGA's (cross-dipole, helix, spiral, and slot antennas), the helix antenna is the most inexpensive. One can also change the size, shape, or pitch angle of the helix to optimize the gain in the desired direction. Therefore, the helix antenna is selected for further study. Both 2-arm and 4-arm helices are studied theoretically and experimentally to determine the antenna's performance and the scattering effects from the helicopter body and the blades. The multipath, Doppler, and Doppler rate issues as well as the periodic fading effects caused by the helicopter rotor blades will be briefly discussed in the paper.

  7. Optimal helicopter trajectory planning for terrain following flight

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.

    1990-01-01

    Helicopters operating in high threat areas have to fly close to the earth surface to minimize the risk of being detected by the adversaries. Techniques are presented for low altitude helicopter trajectory planning. These methods are based on optimal control theory and appear to be implementable onboard in realtime. Second order necessary conditions are obtained to provide a criterion for finding the optimal trajectory when more than one extremal passes through a given point. A second trajectory planning method incorporating a quadratic performance index is also discussed. Trajectory planning problem is formulated as a differential game. The objective is to synthesize optimal trajectories in the presence of an actively maneuvering adversary. Numerical methods for obtaining solutions to these problems are outlined. As an alternative to numerical method, feedback linearizing transformations are combined with the linear quadratic game results to synthesize explicit nonlinear feedback strategies for helicopter pursuit-evasion. Some of the trajectories generated from this research are evaluated on a six-degree-of-freedom helicopter simulation incorporating an advanced autopilot. The optimal trajectory planning methods presented are also useful for autonomous land vehicle guidance.

  8. A laser imaging system for helicopter avoidance obstacle

    NASA Astrophysics Data System (ADS)

    Wang, WeiRan; Yuan, HongChun; Jin, Yuan

    2006-09-01

    Rotorcraft flying in low-altitude is endangered by power lines or telephone wires. The development of automated tools that can detect obstacles in the flight path and warn the crew would significantly reduce the workload of pilot and increase the safety. Detection and warning are rudimental demand and desire for Helicopter Avoidance Obstacle System (HAOS). And that, An advanced HAOS may be capable of classifying thin obstacles and enhanced vision with distances of obstacles. A laser 3D imaging system for helicopter avoidance obstacle (HAO) had been developed successfully. The laser 3D imaging helicopter avoidance obstacle system can not only detect thin obstacles but also catch more information of all objects of the area in front of the helicopter as possible. Then the information is transformed into intuitionist 3D image modality. In this paper, special features and characteristic of the laser imaging system for HAO are analyzed and discussed. Several design gist for this system are proposed. Especially, the developed zero backlash imaging technology and real-time dynamic imaging synchronizing with radar space scanning are described. The technique implementation problem and the system structure are given as well. Finally, the results of system ground test are presented. The ground test of the developed laser imaging system has demonstrated that the developed imaging system performance can achieve and satisfy commendably the requirements of the mission to prevent "wire strike".

  9. Revolutionary Concepts for Helicopter Noise Reduction: SILENT Program

    NASA Technical Reports Server (NTRS)

    Edwards, Bryan; Cox, Charles; Booth, Earl R., Jr. (Technical Monitor)

    2002-01-01

    As part of a NASA initiative to reduce helicopter main rotor noise, a Phase 1 study has been performed of candidate noise reduction concepts. Both conventional and novel design technologies have been analyzed that reduce the community impact of helicopter operations. In this study the noise reduction potential and design implications are assessed for conventional means of noise reduction, e.g., tip speed reduction, tip shapes and airfoil tailoring, and for two innovative design concepts: modulated blade spacing and x-force control. Main rotor designs that incorporate modulated blade spacing are shown to have reduced peak noise levels in most flight operations. X-force control alters the helicopter's force balance whereby the miss distance between main rotor blades and shed vortices can be controlled. This control provides a high potential to mitigate BVI noise radiation. Each concept is evaluated using best practice design and analysis methods, achieving the study's aim to significantly reduce noise with minimal performance degradation and no vibration increase. It is concluded that a SILENT main rotor design, incorporating the modulated blade spacing concept, offers significantly reduced noise levels and the potential of a breakthrough in how a helicopter's sound is perceived and judged. The SILENT rotor represents a definite advancement in the state-of-the-art and is selected as the design concept for demonstration in Phase 2. A Phase 2 Implementation Plan is developed for whirl cage and wind tunnel evaluations of a scaled model SILENT rotor.

  10. 78 FR 9793 - Airworthiness Directives; Bell Helicopter Textron Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-12

    ... helicopters. AD Requirements This AD supersedes AD 2011-08-01 (76 FR 18865, April 6, 2011) and requires for... issued AD 2011-08-01, Amendment 39-16651 (76 FR 18865, April 6, 2011), which superseded previously... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will...

  11. 78 FR 9309 - Airworthiness Directives; MD Helicopters, Inc., Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-08

    ... helicopters, AD 2006-18-01 (71 FR 51095, August 29, 2006) contains additional TIS life limits for T-T straps...; email john.cecil@faa.gov . SUPPLEMENTARY INFORMATION: Discussion On July 19, 2012, at 77 FR 42459, the... comments on the NPRM (77 FR 42459, July 19, 2012). FAA's Determination We have reviewed the...

  12. 77 FR 57005 - Airworthiness Directives; Bell Helicopter Textron Canada Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-17

    ... INFORMATION: Discussion On March 29, 2012, at 77 FR 18970, the Federal Register published our notice of... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); (3) Will not... (BHTC) Model 407 helicopters. This AD requires you to replace tailboom-attachment hardware...

  13. 78 FR 38546 - Airworthiness Directives; Bell Helicopter Textron Canada Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-27

    ... to the tailboom.'' On February 1, 2013, at 78 FR 7308, the Federal Register published our notice of... no comments on the NPRM (78 FR 7308, February 1, 2013). FAA's Determination These helicopters have... Executive Order 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...

  14. Computational Fluid Dynamics For Helicopters

    NASA Technical Reports Server (NTRS)

    Caradonna, F. X.; Mccroskey, W. J.

    1990-01-01

    Powerful computer codes undergoing development. Report reviews development of computational fluid dynamics (CFD) for prediction of airflow around rotary wings of helicopters. Reviews progress in following endeavors: Prediction and verification of flows under various operating conditions; calculation of interactions between rotor blades and vortexes; analysis of viscous, transonic flows about airfoils; and study of formation of vortexes at tips of rotors.

  15. A new passive helicopter detector

    SciTech Connect

    Elliott, G.R.

    1985-01-01

    Sandia has developed a new helicopter detector. The device relies on the correlation between the acoustic wave from the helicopter and the resulting coupled seismic wave. A significant feature of this approach is that the detector is completely passive; there is no radio frequency radiation. Intended for deployment as a perimeter sensor around a site, the unit offers a low nuisance/false alarm rate and a high probability of detection for a wide range of helicopters. Reliable detection occurs when the target is at high altitude and also very near the earth's surface. Detection ranges start at one kilometre for the small, four-place, civilian helicopter and approach five kilometres for heavier, military types. The system has two parts: a transducer package containing a microphone and a geophone and a digital processor. Development is underway for a model which will be AC powered and well suited to permanent facilities. A prototype unit using a lightweight, battery powered processor is being constructed for rapid-deployment applications.

  16. Helicopter Toy and Lift Estimation

    ERIC Educational Resources Information Center

    Shakerin, Said

    2013-01-01

    A $1 plastic helicopter toy (called a Wacky Whirler) can be used to demonstrate lift. Students can make basic measurements of the toy, use reasonable assumptions and, with the lift formula, estimate the lift, and verify that it is sufficient to overcome the toy's weight. (Contains 1 figure.)

  17. Helicopter Toy and Lift Estimation

    NASA Astrophysics Data System (ADS)

    Shakerin, Said

    2013-05-01

    A1 plastic helicopter toy (called a Wacky Whirler) can be used to demonstrate lift. Students can make basic measurements of the toy, use reasonable assumptions and, with the lift formula, estimate the lift, and verify that it is sufficient to overcome the toy's weight.

  18. Helicopter collision avoidance and brown-out recovery with HELLAS

    NASA Astrophysics Data System (ADS)

    Seidel, Christian; Schwartz, Ingo; Kielhorn, Peter

    2008-10-01

    EADS Germany is the world market leader in commercial and military Helicopter Laser Radar (HELLAS) Obstacle Warning Systems. The HELLAS-Warning System has been introduced into the market in 2000, is in service at German Federal Police and Royal Thai Air Force. HELLAS was also successfully evaluated by the Foreign Comparative Test Program (FCT) of the U.S. Army and other governmental agencies. Currently the successor system for military applications, HELLAS-Awareness, is in qualification phase. It will have extended sensor performance, enhanced real-time data processing capabilities and advanced human machine interface (HMI) features. Flight tests on NH90 helicopter have been successfully performed. Helicopter series integration is scheduled to begin from 2009. We will give an outline of the new sensor unit concerning detection technology and helicopter integration aspects. The system provides a widespread field of view with additional dynamic line of sight steering and a large detection range in combination with a high frame rate. We will show the HMI representations. This HELLAS system is the basis for a 3 dimensional see-and-remember-system for brown-out recovery. When landing in sandy or dusty areas the downwash of the helicopter rotor causes clouds of visually-restrictive material that can completely obstruct the pilot's outside reference, resulting in a complete loss of situational awareness and spatial orientation of the pilot which can end up in total loss of aircraft control and dangerous accidents. The brown-out recovery system presented here creates an augmented enhanced synthetic vision of the landing area with the surrounding which is based on HELLAS range image data as well as altimeter and inertial reference information.

  19. Heart Attack Recovery FAQs

    MedlinePlus

    ... Pressure High Blood Pressure Tools & Resources Stroke More Heart Attack Recovery FAQs Updated:Aug 24,2016 Most people ... recovery. View an animation of a heart attack . Heart Attack Recovery Questions and Answers What treatments will I ...

  20. Advancement of photonics for space and other platforms: open optical interconnect architecture (OOIA)

    NASA Astrophysics Data System (ADS)

    Gaydeski, Michael S.

    1997-07-01

    Continuous investigation of new technologies for avionics and space processing has led to the improvement of applications capabilities and processing for tactical platforms (commercial and government satellites, tactical asset such as the USN Reconnaissance Fighter F/A-18R, USAF Fighter F-16, various helicopters, etc.,) and surveillance platforms (commercial and government satellites, Joint Surveillance Target Attack Radar System, Advanced Warning and Control System). This paper focuses on the potential benefits of inserting optical interconnect technology into these platforms while subscribing an Open Optical Interconnect Architecture concept and a methodology for systems development and integration.

  1. 78 FR 33204 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-04

    ... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation... Helicopter Textron, Inc. (Bell) Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final... 214B, 214B-1, and 214ST helicopters with a certain tail rotor hanger bearing (bearing) installed....

  2. Assessment of worm gearing for helicopter transmissions

    NASA Technical Reports Server (NTRS)

    Chaiko, Lev

    1990-01-01

    A high-efficiency hydrostatic worm gear drive for helicopter transmissions is assessed. The example given is for a large cargo helicopter with three 4000-kW engines and transmission reduction ratio of 110. Also contained are: an efficiency calculation, a description of the test stand for evaluating the feasibility of worm gear hydrostatic mesh, a weight calculation, and a comparison with conventional helicopter transmissions of the same power and transmission reduction ratio.

  3. The role of helicopters in seabird censusing

    USGS Publications Warehouse

    Buckley, P.A.; Buckley, F.G.; Schreiber, E.A.; Lee, David S.

    2000-01-01

    The advantages and disadvantages of fixed-wing, helicopter, photographic, vidoegraphic, and ground-count methods of surveying and censusing seabirds are described and compared. Critical terminology is distinguished, and use of small helicopters with multiple, trained observers is firmly recommended for work with diurnal, non-burrow-nesting seabirds in the West Indies and elsewhere. Details of how to use helicopters effectively are provided, along with recommendations for aerial photography, and for data recording, analysis, and presentation.

  4. Portable-Beacon Landing System for Helicopters

    NASA Technical Reports Server (NTRS)

    Davis, Thomas J.; Clary, George R.; Chisholm, John P.; Macdonald, Stanley L.

    1987-01-01

    Prototype beacon landing system (BLS) allows helicopters to make precise landings in all weather. BLS easily added to existing helicopter avionic equipment and readily deployed at remote sites. Small and light, system employs X-band radar and digital processing. Variety of beams pulsed sequentially by ground station after initial interrogation by weather radar of approaching helicopter. Airborne microprocessor processes pulses to determine glide slope, course deviation, and range.

  5. Research On The CH-47B Helicopter

    NASA Technical Reports Server (NTRS)

    Hilbert, Kathryn B.; Tucker, George E.; Chen, Robert T. N.; Fry, Emmett B.; Hindson, William S.

    1988-01-01

    Report describes equipment added to, and research capabilities of CH-47B helicopter. Programmable symbol generator provides display formats for variety of missions - those of vertical-takeoff-and-landing aircraft and helicopters. Powerful general-purpose flight computer in operation. Computer programmable in high-level languages and supports research more efficiently. Flight-control software developed to improve capability of helicopter to perform simulations in flight.

  6. Tradeoff analysis of technology needs for public service helicopters

    NASA Technical Reports Server (NTRS)

    Bauchspies, J. S.; Bryant, W. R., Jr.; Simpson, W. E.

    1985-01-01

    The design requirements for a family or type of Public Service Helicopter (PSH) is examined which will satisfy the needs of municipal and state governments in the following mission areas: Emergency Medical Service--Airborne Rescue Squad; Law Enforcement; Search and Rescue; and Environmental Control (Fire Fighting, Pollution, Resource Management). The report compares both design and performance requirements as specified by the PSH user's group against current technological capabilities, RTOPS and US Army LHX design requirements. The study explores various design trade-offs and options available to the aircraft designer/manufacturer in order to meet the several criteria specified by the PSH user's group. In addition, the report includes a brief assessment of the feasibility of employing certain advanced rotorcraft designs to meet the stringent combination of operational capabilities desired by the Public Service Helicopter Users.

  7. Control of helicopter rotorblade aerodynamics

    NASA Technical Reports Server (NTRS)

    Fabunmi, James A.

    1991-01-01

    The results of a feasibility study of a method for controlling the aerodynamics of helicopter rotorblades using stacks of piezoelectric ceramic plates are presented. A resonant mechanism is proposed for the amplification of the displacements produced by the stack. This motion is then converted into linear displacement for the actuation of the servoflap of the blades. A design which emulates the actuation of the servoflap on the Kaman SH-2F is used to demonstrate the fact that such a system can be designed to produce the necessary forces and velocities needed to control the aerodynamics of the rotorblades of such a helicopter. Estimates of the electrical power requirements are also presented. A Small Business Innovation Research (SBIR) Phase 2 Program is suggested, whereby a bench-top prototype of the device can be built and tested. A collaborative effort between AEDAR Corporation and Kaman Aerospace Corporation is anticipated for future effort on this project.

  8. Shadowgraphs Of Helicopter-Rotor-Tip Vortexes

    NASA Technical Reports Server (NTRS)

    Parthasarathy, Shakkottai P.; Cho, Young I.; Back, Lloyd H.

    1988-01-01

    Optical apparatus produces full-scale or larger shadowgraph of tip vortexes of helicopter rotor. Stroboscope projects shadow image of helicopter rotor on large, square screen. Commercial, highly reflecting projection screen used; simply projecting image on white wall does not yield enough light for photographing vortexes with standard 35-mm camera. Apparatus adapts to use in large wind tunnels.

  9. Surveys of Students Challenge "Helicopter Parent" Stereotypes

    ERIC Educational Resources Information Center

    Hoover, Eric

    2008-01-01

    Stories of "helicopter parents" abound. But several longtime student-affairs officials agree that while helicopter parents are real, their numbers--and behaviors--have been exaggerated. Parental involvement on campus, they say, is usually more of a help than a headache, for students and colleges alike. Some officials believe colleges must do even…

  10. Pneumatic boot for helicopter rotor deicing

    NASA Technical Reports Server (NTRS)

    Blaha, B. J.; Evanich, P. L.

    1981-01-01

    Pneumatic deicer boots for helicopter rotor blades were tested. The tests were conducted in the 6 by 9 ft icing research tunnel on a stationary section of a UH-IH helicopter main rotor blade. The boots were effective in removing ice and in reducing aerodynamic drag due to ice.

  11. PAN AIR analysis of the NASA/MCAIR 279-3: An advanced supersonic V/STOL fighter/attack aircraft

    NASA Technical Reports Server (NTRS)

    Madson, Michael D.; Erickson, Larry L.

    1986-01-01

    PAN AIR is a computer program for predicting subsonic or supersonic linear potential flow about arbitrary configurations. The program was applied to a highly complex single-engine-cruise V/STOL fighter/attack aircraft. Complexities include a close-coupled canard/wing, large inlets, and four exhaust nozzles mounted directly under the wing and against the fuselage. Modeling uncertainties involving canard wake location and flow-through approximation through the inlet and the exhaust nozzles were investigated. The recently added streamline capability of the program was utilized to evaluate visually the predicted flow over the model. PAN AIR results for Mach numbers of 0.6, 0.9, and angles of attack of 0, 5, and 10 deg. were compared with data obtained in the Ames 11- by 11-Foot Transonic Wind tunnel, at a Reynolds number of 3.69 x 10 to the 6th power based on c bar.

  12. The Helicopter Antenna Radiation Prediction Code (HARP)

    NASA Technical Reports Server (NTRS)

    Klevenow, F. T.; Lynch, B. G.; Newman, E. H.; Rojas, R. G.; Scheick, J. T.; Shamansky, H. T.; Sze, K. Y.

    1990-01-01

    The first nine months effort in the development of a user oriented computer code, referred to as the HARP code, for analyzing the radiation from helicopter antennas is described. The HARP code uses modern computer graphics to aid in the description and display of the helicopter geometry. At low frequencies the helicopter is modeled by polygonal plates, and the method of moments is used to compute the desired patterns. At high frequencies the helicopter is modeled by a composite ellipsoid and flat plates, and computations are made using the geometrical theory of diffraction. The HARP code will provide a user friendly interface, employing modern computer graphics, to aid the user to describe the helicopter geometry, select the method of computation, construct the desired high or low frequency model, and display the results.

  13. 46 CFR 108.487 - Helicopter deck fueling operations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter deck fueling operations. 108.487 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.487 Helicopter deck fueling operations. (a) Each helicopter landing deck on which fueling operations...

  14. 46 CFR 108.487 - Helicopter deck fueling operations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter deck fueling operations. 108.487 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.487 Helicopter deck fueling operations. (a) Each helicopter landing deck on which fueling operations...

  15. 46 CFR 108.489 - Helicopter fueling facilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter fueling facilities. 108.489 Section 108.489... AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.489 Helicopter fueling facilities. (a) Each helicopter fueling facility must have a fire protection system...

  16. 14 CFR 36.11 - Acoustical change: Helicopters.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Acoustical change: Helicopters. 36.11...: Helicopters. This section applies to all helicopters in the primary, normal, transport, and restricted... appendix H of this part, or, for helicopters having a maximum certificated takeoff weight of not more...

  17. 46 CFR 108.489 - Helicopter fueling facilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter fueling facilities. 108.489 Section 108.489... AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.489 Helicopter fueling facilities. (a) Each helicopter fueling facility must have a fire protection system...

  18. Helicopter Operations and Personnel Safety (Helirescue Manual). Fourth Edition.

    ERIC Educational Resources Information Center

    Dalle-Molle, John

    The illustrated manual includes information on various aspects of helicopter rescue missions, including mission management roles for key personnel, safety rules around helicopters, requests for helicopter support, sample military air support forms, selection of landing zones, helicopter evacuations, rescuer delivery, passenger unloading, crash…

  19. 14 CFR 36.11 - Acoustical change: Helicopters.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Acoustical change: Helicopters. 36.11...: Helicopters. This section applies to all helicopters in the primary, normal, transport, and restricted... appendix H of this part, or, for helicopters having a maximum certificated takeoff weight of not more...

  20. 46 CFR 108.487 - Helicopter deck fueling operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter deck fueling operations. 108.487 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.487 Helicopter deck fueling operations. (a) Each helicopter landing deck on which fueling operations...

  1. 14 CFR 36.11 - Acoustical change: Helicopters.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Acoustical change: Helicopters. 36.11...: Helicopters. This section applies to all helicopters in the primary, normal, transport, and restricted... appendix H of this part, or, for helicopters having a maximum certificated takeoff weight of not more...

  2. 46 CFR 108.489 - Helicopter fueling facilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter fueling facilities. 108.489 Section 108.489... AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.489 Helicopter fueling facilities. (a) Each helicopter fueling facility must have a fire protection system...

  3. 14 CFR 36.11 - Acoustical change: Helicopters.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Acoustical change: Helicopters. 36.11...: Helicopters. This section applies to all helicopters in the primary, normal, transport, and restricted... appendix H of this part, or, for helicopters having a maximum certificated takeoff weight of not more...

  4. 46 CFR 108.487 - Helicopter deck fueling operations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter deck fueling operations. 108.487 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.487 Helicopter deck fueling operations. (a) Each helicopter landing deck on which fueling operations...

  5. 46 CFR 108.487 - Helicopter deck fueling operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter deck fueling operations. 108.487 Section 108... DESIGN AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.487 Helicopter deck fueling operations. (a) Each helicopter landing deck on which fueling operations...

  6. 46 CFR 108.489 - Helicopter fueling facilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter fueling facilities. 108.489 Section 108.489... AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.489 Helicopter fueling facilities. (a) Each helicopter fueling facility must have a fire protection system...

  7. 46 CFR 108.489 - Helicopter fueling facilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter fueling facilities. 108.489 Section 108.489... AND EQUIPMENT Fire Extinguishing Systems Fire Protection for Helicopter Facilities § 108.489 Helicopter fueling facilities. (a) Each helicopter fueling facility must have a fire protection system...

  8. 14 CFR 36.11 - Acoustical change: Helicopters.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Acoustical change: Helicopters. 36.11...: Helicopters. This section applies to all helicopters in the primary, normal, transport, and restricted... appendix H of this part, or, for helicopters having a maximum certificated takeoff weight of not more...

  9. An Experimental Investigation of Helicopter Rotor Hub Fairing Drag Characteristics

    NASA Technical Reports Server (NTRS)

    Sung, D. Y.; Lance, M. B.; Young, L. A.; Stroub, R. H.

    1989-01-01

    A study was done in the NASA 14- by 22-Foot Wind Tunnel at Langley Research Center on the parasite drag of different helicopter rotor hub fairings and pylons. Parametric studies of hub-fairing camber and diameter were conducted. The effect of hub fairing/pylon clearance on hub fairing/pylon mutual interference drag was examined in detail. Force and moment data are presented in tabular and graphical forms. The results indicate that hub fairings with a circular-arc upper surface and a flat lower surface yield maximum hub drag reduction; and clearance between the hub fairing and pylon induces high mutual-interference drag and diminishes the drag-reduction benefit obtained using a hub fairing with a flat lower surface. Test data show that symmetrical hub fairings with circular-arc surfaces generate 74 percent more interference drag than do cambered hub fairings with flat lower surfaces, at moderate negative angle of attack.

  10. The impact of urban operations on helicopter noise requirements

    NASA Technical Reports Server (NTRS)

    Spector, S. R.

    1978-01-01

    The interrelationship of urban helicopter operations, helicopter noise, and the establishment of urban public-use heliports is discussed. Public resistance to urban helicopter operations due to concern for safety and noise is shown to negatively impact the establishment of public-use heliports in urban centers. It is indicated that increased government and industry effort to reduce helicopter noise is needed to ensure continued growth in the helicopter industry.

  11. About Heart Attacks

    MedlinePlus

    ... survive. A heart attack occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or ... survive. A heart attack occurs when the blood flow that brings oxygen to the heart muscle is severely reduced or ...

  12. Identifying and analyzing methods for reducing the energy consumption of helicopters

    NASA Technical Reports Server (NTRS)

    Davis, S. J.; Rosenstein, H. J.

    1976-01-01

    Reductions in helicopter energy consumption can be accomplished through the use of advanced technology in the areas of powerplant design, improved rotor efficiency, reduced parasite drag, and reduced structural empty weight. Baseline helicopters incorporating technology were designed for a short range (200 n mi) and a very short haul (100 n mi) mission scenario. Parametric analyses were then conducted to determine the impact of technology improvement. Many of the parameters varied are interrelated. A summary of such interactions is presented, and some additional sensitivity values were added so that energy reduction and DOC as affected by the major technological factors or operational modes are clearly defined.

  13. Low-noise, high-strength, spiral-bevel gears for helicopter transmissions

    NASA Astrophysics Data System (ADS)

    Lewicki, David G.; Handschuh, Robert F.; Henry, Zachary S.; Litvin, Faydor L.

    1994-05-01

    Advanced-design spiral-bevel gears were tested in an OH-58D helicopter transmission using the NASA 500-hp Helicopter Transmission Test Stand. Three different gear designs tested included: the current design of the OH-58D transmission; a higher-strength design the same as the current but with a full fillet radius to reduce gear tooth bending stress (and thus, weight); and a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.

  14. Hydrogen Fuel Cell on a Helicopter: A System Engineering Approach

    NASA Astrophysics Data System (ADS)

    Nesheiwat, Rod

    Hydrogen fuel cells have been previously investigated as a viable replacement to traditional gas turbine auxiliary power unit onboard fixed wing commercial jets. However, so far no study has attempted to extend their applicability to rotary wing aircrafts. To aid in the advancement of such innovative technologies, a holistic technical approach is required to ensure risk reduction and cost effectiveness throughout the product lifecycle. This paper will evaluate the feasibility of replacing a gas turbine auxiliary power unit on a helicopter with a direct hydrogen, air breathing, proton exchange membrane fuel cell, all while emphasizing a system engineering approach that utilize a specialized set of tools and artifacts.

  15. Wind tunnel investigation of helicopter-rotor wake effects on three helicopter fuselage models

    NASA Technical Reports Server (NTRS)

    Wilson, J. C.; Mineck, R. E.

    1975-01-01

    The effects of rotor wake on helicopter fuselage aerodynamic characteristics were investigated in the Langley V/STOL tunnel. Force, moment, and pressure data were obtained on three fuselage models at various combinations of windspeed, sideslip angle, and pitch angle. The data show that the influence of rotor wake on the helicopter fuselage yawing moment imposes a significant additional thrust requirement on the tail rotor of a single-rotor helicopter at high sideslip angles.

  16. Flow analysis for the nacelle of an advanced ducted propeller at high angle-of-attack and at cruise with boundary layer control

    NASA Technical Reports Server (NTRS)

    Hwang, D. P.; Boldman, D. R.; Hughes, C. E.

    1994-01-01

    An axisymmetric panel code and a three dimensional Navier-Stokes code (used as an inviscid Euler code) were verified for low speed, high angle of attack flow conditions. A three dimensional Navier-Stokes code (used as an inviscid code), and an axisymmetric Navier-Stokes code (used as both viscous and inviscid code) were also assessed for high Mach number cruise conditions. The boundary layer calculations were made by using the results from the panel code or Euler calculation. The panel method can predict the internal surface pressure distributions very well if no shock exists. However, only Euler and Navier-Stokes calculations can provide a good prediction of the surface static pressure distribution including the pressure rise across the shock. Because of the high CPU time required for a three dimensional Navier-Stokes calculation, only the axisymmetric Navier-Stokes calculation was considered at cruise conditions. The use of suction and tangential blowing boundary layer control to eliminate the flow separation on the internal surface was demonstrated for low free stream Mach number and high angle of attack cases. The calculation also shows that transition from laminar flow to turbulent flow on the external cowl surface can be delayed by using suction boundary layer control at cruise flow conditions. The results were compared with experimental data where possible.

  17. INVITED PAPER: Application of an active device for helicopter noise reduction in JAXA

    NASA Astrophysics Data System (ADS)

    Saito, Shigeru; Kobiki, Noboru; Tanabe, Yasutada

    2010-02-01

    Important issues in noise problems for current helicopters are described. An active tab (AT) was developed as a new active device for noise/vibration reduction under research cooperation between Japan Aerospace Exploration Agency (JAXA) and Kawada Industries, Inc. The wind tunnel test was conducted in order to investigate the effectiveness of the AT on the aeroacoustic characteristics of a helicopter. From the wind tunnel test, the capability of reducing blade vortex interaction (BVI) noise by an AT was verified. A new control law using instantaneous pressure change on a blade during BVI phenomena was introduced and applied to the wind tunnel testing. This new control law shows reasonable controllability for helicopter noise reduction. Furthermore, in order to analyze noise characteristics, the advanced computational fluid dynamics (CFD) code named JAXA_ov3d was developed in JAXA and extended to include CFD-CSD (computational structure dynamics) coupling by using the beam theory for blade deformation.

  18. Human-robot interaction for field operation of an autonomous helicopter

    NASA Astrophysics Data System (ADS)

    Jones, Henry L.; Frew, Eric W.; Woodley, Bruce R.; Rock, Stephen M.

    1999-01-01

    The robustness of autonomous robotic systems to unanticipated circumstances is typically insufficient for use in the field. The many skills of a human user often fill this gap in robotic capability. To incorporate the human into the system, a useful interaction between man and machine must exist. This interaction should enable useful communication to be exchanged in a natural way between human and robot on a variety of levels. This paper describes the current human-robot interaction of the Stanford HUMMINGBIRD autonomous helicopter. In particular, the paper discuses the elements of the system that enable multiple levels of communication. An intelligent system agent manages the different inputs given to the helicopter. An advanced user interface gives the user and helicopter a method for exchanging useful information. Using this human-robot interaction, the HUMMINGBIRD has carried out various autonomous search, tracking, and retrieval missions.

  19. Seven Deadliest Network Attacks

    SciTech Connect

    Prowell, Stacy J; Borkin, Michael; Kraus, Robert

    2010-05-01

    Do you need to keep up with the latest hacks, attacks, and exploits effecting networks? Then you need "Seven Deadliest Network Attacks". This book pinpoints the most dangerous hacks and exploits specific to networks, laying out the anatomy of these attacks including how to make your system more secure. You will discover the best ways to defend against these vicious hacks with step-by-step instruction and learn techniques to make your computer and network impenetrable. Attacks detailed in this book include: Denial of Service; War Dialing; Penetration 'Testing'; Protocol Tunneling; Spanning Tree Attacks; Man-in-the-Middle; and, Password Replay. Knowledge is power, find out about the most dominant attacks currently waging war on computers and networks globally. Discover the best ways to defend against these vicious attacks; step-by-step instruction shows you how. Institute countermeasures, don't be caught defenseless again, learn techniques to make your computer and network impenetrable.

  20. Study on Safety Technology Scheme of the Unmanned Helicopter

    NASA Astrophysics Data System (ADS)

    Lin, Z.; Zhang, W.; Chen, S.; Liu, T.; Yao, Y.

    2013-08-01

    Nowadays the unmanned helicopter is widely used for its' unique strongpoint, however, the high failure rate of unmanned helicopter seriously limits its further application and development. For solving the above problems, in this paper, the reasons for the high failure rate of unmanned helicopter is analyzed and the corresponding solution schemes are proposed. The main problem of the failure cause of the unmanned helicopter is the aircraft engine fault, and the failure cause of the unmanned helicopter is analyzed particularly. In order to improving the safety performance of unmanned helicopter system, the scheme of adding the safety parachute system to the unmanned helicopter system is proposed and introduced. These schemes provide the safety redundancy of the unmanned helicopter system and lay on basis for the unmanned helicopter applying into residential areas.

  1. Law of Torsional Vibration and Discussion on Vibration Suppression Based on Helicopter/Engine System

    NASA Astrophysics Data System (ADS)

    Miao, Lizhen; Zhang, Haibo; Ning, Jingtao

    2016-04-01

    With both the advantages like attacking close targets and the disadvantages especially like dynamic coupling, helicopter deserves more investigations these days. This paper did dynamic study both in a simplified and a multi-degree of freedom, comprehensive helicopter model, so that to reveal the law of torsional vibration. In the simplified model, the law how arbitrary parameter affects the first-order vibration mode, is discussed. Then, the validation is done in a multi-degree of freedom model by means of the fast Fourier transformation (FFT) method. In this case, how the low-frequency vibration mode relates with the first-order vibration mode is clearly presented, as well as the research direction to design a filter. Lastly, a simple filter is designed with some simulations.

  2. Transonic Aeroelasticity Analysis For Helicopter Rotor Blade

    NASA Technical Reports Server (NTRS)

    Chang, I-Chung; Gea, Lie-Mine; Chow, Chuen-Yen

    1991-01-01

    Numerical-simulation method for aeroelasticity analysis of helicopter rotor blade combines established techniques for analysis of aerodynamics and vibrations of blade. Application of method clearly shows elasticity of blade modifies flow and, consequently, aerodynamic loads on blade.

  3. Small crack test program for helicopter materials

    NASA Technical Reports Server (NTRS)

    Annigeri, Bal; Schneider, George

    1994-01-01

    Crack propagation tests were conducted to determine crack growth behavior in five helicopter materials for surface cracks between 0.005 to 0.020 inches in depth. Constant amplitude tests were conducted at stress ratios R equals 0.1 and 0.5, and emphasis was placed on near threshold data (i.e., 10-8 to 10-6 inches/cycle). Spectrum tests were conducted using a helicopter spectrum. The test specimen was an unnotched tension specimen, and cracks were initiated from a small EDM notch. An optical/video system was used to monitor crack growth. The material for the test specimens was obtained from helicopter part forgings. Testing was conducted at stresses below yield to reflect actual stresses in helicopter parts.

  4. NASA-Langley helicopter tower instrumentation systems

    NASA Technical Reports Server (NTRS)

    Stoffel, S. W.

    1974-01-01

    Background information is presented for the helicopter rotor test facility, in preface to a more detailed discussion of major subsystems equipment, including error considerations, frequency response, and display instrumentation.

  5. Small crack test program for helicopter materials

    NASA Astrophysics Data System (ADS)

    Annigeri, Bal; Schneider, George

    1994-09-01

    Crack propagation tests were conducted to determine crack growth behavior in five helicopter materials for surface cracks between 0.005 to 0.020 inches in depth. Constant amplitude tests were conducted at stress ratios R equals 0.1 and 0.5, and emphasis was placed on near threshold data (i.e., 10-8 to 10-6 inches/cycle). Spectrum tests were conducted using a helicopter spectrum. The test specimen was an unnotched tension specimen, and cracks were initiated from a small EDM notch. An optical/video system was used to monitor crack growth. The material for the test specimens was obtained from helicopter part forgings. Testing was conducted at stresses below yield to reflect actual stresses in helicopter parts.

  6. Minimum Power Requirements and Optimal Rotor Design for Conventional, Compound, and Coaxial Helicopters Using Higher Harmonic Control

    NASA Astrophysics Data System (ADS)

    Giovanetti, Eli B.

    This thesis presents a method for computing the optimal aerodynamic performance of conventional, compound, and coaxial helicopters in trimmed forward flight with a limited set of design variables, including the blade's radial twist and chord distributions and conventional and higher harmonic blade pitch control. The optimal design problem, which is cast as a variational statement, minimizes the sum of the induced and viscous power required to develop a prescribed lift and/or thrust. The variational statement is discretized and solved efficiently using a vortex-lattice technique. We present two variants of the analysis. In the first, the sectional blade aerodynamics are modeled using a linear lift curve and a quadratic drag polar, and flow angles are assumed to be small. The result is a quadratic programming problem that yields a linear set of equations to solve for the unknown optimal design variables. In the second approach, the problem is cast as a constrained nonlinear optimization problem, which is solved using Newton iteration. This approach, which accounts for realistic lift and drag coefficients including the effects of stall and the attendant increase in drag at high angles of attack, is capable of optimizing the blade planform in addition to the radial twist distribution and conventional and higher harmonic blade pitch control. We show that for conventional rotors, coaxial counterrotating rotors, and a wing-rotor compound, using radially varying twist and chord distributions and higher harmonic blade pitch control can produce significant reductions in required power, especially at high advance ratios.

  7. Stability Analysis of the Slowed-Rotor Compound Helicopter Configuration

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Floros, Matthew W.

    2004-01-01

    The stability and control of rotors at high advance ratio are considered. Teetering, articulated, gimbaled, and rigid hub types are considered for a compound helicopter (rotor and fixed wing). Stability predictions obtained using an analytical rigid flapping blade analysis, a rigid blade CAMRAD II model, and an elastic blade CAMRAD II model are compared. For the flapping blade analysis, the teetering rotor is the most stable, 5howing no instabilities up to an advance ratio of 3 and a Lock number of 18. With an elastic blade model, the teetering rotor is unstable at an advance ratio of 1.5. Analysis of the trim controls and blade flapping shows that for small positive collective pitch, trim can be maintained without excessive control input or flapping angles.

  8. Stability Analysis of the Slowed-Rotor Compound Helicopter Configuration

    NASA Technical Reports Server (NTRS)

    Floros, Matthew W.; Johnson, Wayne

    2007-01-01

    The stability and control of rotors at high advance ratio are considered. Teetering, articulated, gimbaled, and rigid hub types are considered for a compound helicopter (rotor and fixed wing). Stability predictions obtained using an analytical rigid flapping blade analysis, a rigid blade CAMRAD II model, and an elastic blade CAMRAD II model are compared. For the flapping blade analysis, the teetering rotor is the most stable, showing no instabilities up to an advance ratio of 3 and a Lock number of 18. A notional elastic blade model of a teetering rotor is unstable at an advance ratio of 1.5, independent of pitch frequency. Analysis of the trim controls and blade flapping shows that for small positive collective pitch, trim can be maintained without excessive control input or flapping angles.

  9. Tail Rotor Airfoils Stabilize Helicopters, Reduce Noise

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Founded by former Ames Research Center engineer Jim Van Horn, Van Horn Aviation of Tempe, Arizona, built upon a Langley Research Center airfoil design to create a high performance aftermarket tail rotor for the popular Bell 206 helicopter. The highly durable rotor has a lifetime twice that of the original equipment manufacturer blade, reduces noise by 40 percent, and displays enhanced performance at high altitudes. These improvements benefit helicopter performance for law enforcement, military training, wildfire and pipeline patrols, and emergency medical services.

  10. Civil helicopter design and operational requirement

    NASA Technical Reports Server (NTRS)

    Waters, K. T.

    1978-01-01

    Design and operational requirements and other factors that have a restraining influence on expansion of the helicopter market are discussed. The needs of operators, users, pilots and the community at large are examined. The impact of future technology developments and other trends such as use, energy shortages, and civil and military helicopter requirements and development is assessed. Areas where research and development are needed to provide opportunities for lowering life cycle costs and removing barriers to further expansion of the industry are analyzed.

  11. The effective acoustic environment of helicopter crewmen

    NASA Technical Reports Server (NTRS)

    Camp, R. T., Jr.; Mozo, B. T.

    1978-01-01

    Methods of measuring the composite acoustic environment of helicopters in order to quantify the effective acoustic environment of the crewmen and to assess the real acoustic hazards of the personnel are examined. It is indicated that the attenuation characteristics of the helmets and hearing protectors and the variables of the physiology of the human ear be accounted for in determining the effective acoustic environment of Army helicopter crewmen as well as the acoustic hazards of voice communications systems noise.

  12. Helicopter training simulators: Key market factors

    NASA Technical Reports Server (NTRS)

    Mcintosh, John

    1992-01-01

    Simulators will gain an increasingly important role in training helicopter pilots only if the simulators are of sufficient fidelity to provide positive transfer of skills to the aircraft. This must be done within an economic model of return on investment. Although rotor pilot demand is still only a small percentage of overall pilot requirements, it will grow in significance. This presentation described the salient factors influencing the use of helicopter training simulators.

  13. 78 FR 51126 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-20

    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice...

  14. 78 FR 34958 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell), Model Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... helicopter. Actions Since Existing AD Was Issued Since we issued AD 2009-05-09 (74 FR 11001, March 16, 2009... control of the helicopter. (c) Affected ADs This AD supersedes AD 2009-05-09, Amendment 39-15833 (74 FR..., we issued AD 2009-05-09, Amendment 39-15833 (74 FR 11001, March 16, 2009), for Bell Model 412,...

  15. 75 FR 52912 - Airworthiness Directives; Bell Helicopter Textron Canada Limited Model 427 Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-30

    ... 12866; 2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron Canada Limited Model 427 Helicopters AGENCY: Federal Aviation Administration (FAA), Department...

  16. 78 FR 41886 - Airworthiness Directives; Bell Helicopter Textron Canada Limited Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-12

    ...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... Federal Aviation Administration 14 CFR Part 39 RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron Canada Limited Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice...

  17. 76 FR 18865 - Airworthiness Directives; Bell Helicopter Textron, Inc. Model 212 Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-06

    ... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), (3) Will not...-005-AD; Amendment 39-16651; AD 2011-08-01] RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron, Inc. Model 212 Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final...

  18. 78 FR 56592 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-13

    ... chain and subsequent loss of directional control of the helicopter. On April 25, 2013, at 78 FR 24368... helicopter. (c) Affected ADs This AD supersedes AD 76-12-07, Amendment 39-2640 (41 FR 23939, June 14, 1976... 76-12-07, Amendment 39-2640 (41 FR 23939, June 14, 1976), Docket No. 76-SW-19, which...

  19. 78 FR 27869 - Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Model Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-13

    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... identified in this proposed AD, contact Bell Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir..., contact Bell Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4,...

  20. 75 FR 69862 - Airworthiness Directives; MD Helicopters, Inc. Model MD900 Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... beam bolt hole locations during maintenance on two MDHI Model MD900 helicopters. The actions specified... loss of control of the helicopter. DATES: Effective December 1, 2010, to all persons except those... AD was prompted by two reports of cracks detected in the hub in the area near the flex beam bolt...

  1. Correlation of airloads on a two-bladed helicopter rotor

    NASA Technical Reports Server (NTRS)

    Fernandez, Francisco J.; Johnson, Wayne

    1993-01-01

    Airloads measured on a two-bladed helicopter rotor in flight during the Ames' Tip Aerodynamic and Acoustic Test are compared with calculations from a comprehensive helicopter analysis (CAMRAD/JA), and the pressures compared with calculations from a full-potential rotor code (FPR). The flight-test results cover an advance ratio range of 0.19 to 0.38. The lowest-speed case is characterized by the presence of significant blade-vortex interactions. Good correlation of peak-to-peak vortex-induced loads and the corresponding pressures is obtained. Results of the correlation for this two-bladed rotor are substantially similar to those for three- and four-bladed rotors, including the tip-vortex core size for best correlation, calculation of the peak-to-peak loads on the retreating side, and calculation of vortex iduced loads on inboard radial stations. The higher-speed cases are characterized by the presence of transonic flow on the outboard sections of the blade. Comparison of calculated and measured airloads on the advancing side is not considered appropriate because the presence of shocks makes chordwise integration of the measured data difficult. However, good correlation of the corresponding pressures is obtained.

  2. Wild boar attacks.

    PubMed

    Gunduz, Abdulkadir; Turedi, Suleyman; Nuhoglu, Irfan; Kalkan, Asim; Turkmen, Suha

    2007-01-01

    Attacks on humans by wild boar (Sus scrofa) are occasionally reported in rural areas of Turkey. While fatalities are rare, individuals may sustain significant soft tissue trauma. Lower extremity lacerations of up to 10 cm in length and 4 cm deep were seen in the 3 cases reviewed. Injuries to the upper abdomen and chest occurred in one case. Attacks frequently occur in forested areas covered by dense brushwood, and their incidence is increased during the rutting season. In contrast to other large, feral animal attacks, injuries sustained from wild boar typically are limited to the lower extremities. This case series examines 3 attacks by wild boar in rural Turkey.

  3. 78 FR 51127 - Airworthiness Directives; Various Restricted Category Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-20

    .... Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February....; Robinson Air Crane, Inc.; Rotorcraft Development Corporation; San Joaquin Helicopters; Smith Helicopters...; OAS Parts LLC; Richards Heavylift Helo, Inc.; Robinson Air Crane, Inc.; Rotorcraft...

  4. 78 FR 38826 - Airworthiness Directives; Various Helicopter Models

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-28

    ...; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February... Helicopter Models AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION... various model helicopters with certain part-numbered and serial- numbered Goodrich...

  5. Neural control of helicopter blade-vortex interaction noise

    NASA Astrophysics Data System (ADS)

    Glaessel, Holger; Kloeppel, Valentin; Rudolph, Stephan

    2001-06-01

    Significant reduction of helicopter blade-vortex interaction (BVI) noise is currently one of the most advanced research topics in the helicopter industry. This is due to the complex flow, the close aerodynamic and structural coupling, and the interaction of the blades with the trailing edge vortices. Analytical and numerical modeling techniques are therefore currently still far from a sufficient degree of accuracy to obtain satisfactory results using classical model based control concepts. Neural networks with a proven potential to learn nonlinear relationships implicitly encoded in a training data set are therefore an appropriate and complementary technique for the alternative design of a nonlinear controller for BVI noise reduction. For nonlinear and adaptive control different neural control strategies have been proposed. Two possible approaches, a direct and an indirect neural controller are described. In indirect neural control, the plant has to be identified first by training a network with measured data. The plant network is then used to train the controller network. On the other hand the direct control approach does not rely on an explicit plant model, instead a specific training algorithm (like reinforcement learning) uses the information gathered from interactions with the environment. In the investigation of the BVI noise phenomena, helicopter developers have undertaken substantial efforts in full scale flight tests and wind tunnel experiments. Data obtained in these experiments have been adequately preprocessed using wavelet analysis and filtering techniques and are then used in the design of a neural controller. Neural open-loop control and neural closed-loop control concepts for the BVI noise reduction problem are conceived, simulated and compared against each other in this work in the above mentioned framework.

  6. Transient Ischemic Attack

    MedlinePlus

    Transient Ischemic Attack TIA , or transient ischemic attack, is a "mini stroke" that occurs when a blood clot blocks an artery for a short time. The only ... TIA is that with TIA the blockage is transient (temporary). TIA symptoms occur rapidly and last a ...

  7. Feasibility study for ergonomic analysis and design of future helicopter cockpit systems

    NASA Technical Reports Server (NTRS)

    Hawkins, H. L.

    1985-01-01

    The Army's light scout-attack helicopters (LHXs), planned for deployment in the 1990's, will fly nap-of-the-earth (NOE) missions in high threat environments, often under poor visibility and adverse atmospheric conditions, and probably with a one man crew. A procedure for the analysis of pilot workload that will identify and explicate the main characteristics of those LHX mission components holding overload potential is described. A principled, in-depth, explication of the cognitive demans of LHX piloting is essential to any effective effort to address the human factors issues. A task-analytic procedure that will yield the detail and organizstion needed to achieve these goals is examined.

  8. Durability of commercial aircraft and helicopter composite structures

    NASA Technical Reports Server (NTRS)

    Dexter, H. B.

    1982-01-01

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

  9. Situational awareness of a coordinated cyber attack

    NASA Astrophysics Data System (ADS)

    Sudit, Moises; Stotz, Adam; Holender, Michael

    2005-03-01

    As technology continues to advance, services and capabilities become computerized, and an ever increasing amount of business is conducted electronically the threat of cyber attacks gets compounded by the complexity of such attacks and the criticality of the information which must be secured. A new age of virtual warfare has dawned in which seconds can differentiate between the protection of vital information and/or services and a malicious attacker attaining their goal. In this paper we present a novel approach in the real-time detection of multistage coordinated cyber attacks and the promising initial testing results we have obtained. We introduce INFERD (INformation Fusion Engine for Real-time Decision-making), an adaptable information fusion engine which performs fusion at levels zero, one, and two to provide real-time situational assessment and its application to the cyber domain in the ECCARS (Event Correlation for Cyber Attack Recognition System) system. The advantages to our approach are fourfold: (1) The complexity of the attacks which we consider, (2) the level of abstraction in which the analyst interacts with the attack scenarios, (3) the speed at which the information fusion is presented and performed, and (4) our disregard for ad-hoc rules or a priori parameters.

  10. 14 CFR 135.207 - VFR: Helicopter surface reference requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false VFR: Helicopter surface reference... VFR/IFR Operating Limitations and Weather Requirements § 135.207 VFR: Helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference...

  11. 14 CFR 136.13 - Helicopter performance plan and operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Helicopter performance plan and operations. (a) Each operator must complete a performance plan before each helicopter commercial air tour, or flight operated under 14 CFR 91.146 or 91.147. The pilot in command must... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Helicopter performance plan and...

  12. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline...

  13. 14 CFR 136.13 - Helicopter performance plan and operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Helicopter performance plan and operations. (a) Each operator must complete a performance plan before each helicopter commercial air tour, or flight operated under 14 CFR 91.146 or 91.147. The pilot in command must... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Helicopter performance plan and...

  14. 46 CFR 132.320 - Helicopter-landing decks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  15. 46 CFR 132.320 - Helicopter-landing decks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  16. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline...

  17. 14 CFR 135.207 - VFR: Helicopter surface reference requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false VFR: Helicopter surface reference... VFR/IFR Operating Limitations and Weather Requirements § 135.207 VFR: Helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference...

  18. 14 CFR 135.207 - VFR: Helicopter surface reference requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false VFR: Helicopter surface reference... VFR/IFR Operating Limitations and Weather Requirements § 135.207 VFR: Helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference...

  19. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline...

  20. CHANGES IN FLIGHT TRAINEE PERFORMANCE FOLLOWING SYNTHETIC HELICOPTER FLIGHT TRAINING.

    ERIC Educational Resources Information Center

    CARO, PAUL W., JR.; ISLEY, ROBERT N.

    A STUDY WAS CONDUCTED AT THE U.S. ARMY PRIMARY HELICOPTER SCHOOL, FORT WOLTERS, TEXAS, TO DETERMINE WHETHER THE USE OF A HELICOPTER TRAINING DEVICE WOULD IMPROVE STUDENT PERFORMANCE DURING SUBSEQUENT HELICOPTER CONTACT FLIGHT TRAINING. SUBJECTS WERE TWO EXPERIMENTAL GROUPS AND TWO CONTROL GROUPS OF WARRANT OFFICER CANDIDATES ENROLLED FOR A…

  1. 14 CFR 136.13 - Helicopter performance plan and operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Helicopter performance plan and operations. (a) Each operator must complete a performance plan before each helicopter commercial air tour, or flight operated under 14 CFR 91.146 or 91.147. The pilot in command must... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Helicopter performance plan and...

  2. 14 CFR 136.13 - Helicopter performance plan and operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Helicopter performance plan and operations. (a) Each operator must complete a performance plan before each helicopter commercial air tour, or flight operated under 14 CFR 91.146 or 91.147. The pilot in command must... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Helicopter performance plan and...

  3. 46 CFR 132.320 - Helicopter-landing decks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  4. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline...

  5. 46 CFR 132.320 - Helicopter-landing decks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  6. 14 CFR 136.11 - Helicopter floats for over water.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Helicopter floats for over water. 136.11... TOURS AND NATIONAL PARKS AIR TOUR MANAGEMENT National Air Tour Safety Standards § 136.11 Helicopter floats for over water. (a) A helicopter used in commercial air tours over water beyond the shoreline...

  7. 46 CFR 132.320 - Helicopter-landing decks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter-landing decks. 132.320 Section 132.320 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) OFFSHORE SUPPLY VESSELS FIRE-PROTECTION EQUIPMENT Miscellaneous § 132.320 Helicopter-landing decks. Each vessel with a helicopter-landing deck...

  8. 14 CFR 135.207 - VFR: Helicopter surface reference requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false VFR: Helicopter surface reference... VFR/IFR Operating Limitations and Weather Requirements § 135.207 VFR: Helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference...

  9. 14 CFR 135.207 - VFR: Helicopter surface reference requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false VFR: Helicopter surface reference... VFR/IFR Operating Limitations and Weather Requirements § 135.207 VFR: Helicopter surface reference requirements. No person may operate a helicopter under VFR unless that person has visual surface reference...

  10. Advanced rotorcraft transmission program

    NASA Technical Reports Server (NTRS)

    Bill, Robert C.

    1990-01-01

    The Advanced Rotorcraft Transmission (ART) program is an Army-funded, joint Army/NASA program to develop and demonstrate lightweight, quiet, durable drivetrain systems for next generation rotorcraft. ART addresses the drivetrain requirements of two distinct next generation aircraft classes: Future Air Attack Vehicle, a 10,000 to 20,000 lb. aircraft capable of undertaking tactical support and air-to-air missions; and Advanced Cargo Aircraft, a 60,000 to 80,000 lb. aircraft capable of heavy life field support operations. Both tiltrotor and more conventional helicopter configurations are included in the ART program. Specific objectives of ART include reduction of drivetrain weight by 25 percent compared to baseline state-of-the-art drive systems configured and sized for the next generation aircraft, reduction of noise level at the transmission source by 10 dB relative to a suitably sized and configured baseline, and attainment of at least a 5000 hr mean-time-between-removal. The technical approach for achieving the ART goals includes application of the latest available component, material, and lubrication technology to advanced concept drivetrains that utilize new ideas in gear configuration, transmission layout, and airframe/drivetrain integration. To date, candidate drivetrain systems were carried to a conceptual design stage, and tradeoff studies were conducted resulting in selection of an ART transmission configuration for each of the four contractors. The final selection was based on comparative weight, noise, and reliability studies. A description of each of the selected ART designs is included. Preliminary design of each of the four selected ART transmission was completed, as have mission impact studies wherein comparisons of aircraft mission performance and life cycle costs are undertaken for the next generation aircraft with ART and with the baseline transmission.

  11. All-weather capability for rescue helicopters

    NASA Astrophysics Data System (ADS)

    Kreitmair-Steck, Wolfgang; Haisch, Stefan

    2001-08-01

    In Germany as well as in numerous other countries the air rescue system has been extended significantly since the first operation of the rescue helicopter Christoph 1. The primary target of the air rescue system was to guarantee fast and efficient emergency medical services for victims of accidents. During the years, the scope of the helicopter operations has been extended not only to other types of emergency medical services, but also to secondary medical services like the displacement of patients from hospitals to special service hospitals. While in general the displacement of patients is operated from well known and registered helipads, the primary rescue service currently has to rely on available onboard systems only. Those operations are risky and challenging for the pilots because of time pressure and the danger of obstacles in the environment of the helicopter. In addition, reduced visibility due to fog, rainfall or low light levels can further increase the risks or can make the services unavailable at all. Almost one decade ago, Eurocopter started the investigation of technologies and systems that could help the pilots to perform their tasks with reduced workload and risk, and to allow for a 24 h operation of helicopters irrespective of the weather conditions. After a number of preliminary studies, in 1995 the research program 'All-weather helicopter' has been started as a joint effort of Eurocopter and the supplier industry in Europe. The first phase of the program has been successfully completed in 1999 and the second phase is currently in progress.

  12. A Summary of Operating Conditions Experienced by Three Military Helicopters and a Mountain-Based Commercial Helicopter

    NASA Technical Reports Server (NTRS)

    Connor, Andrew B.

    1960-01-01

    The results of a survey of the flight conditions experienced by three military helicopters engaged in simulated and actual military missions, and a commercial helicopter operated in the mountainous terrain surrounding Denver, CO, are presented. The data, obtained with NASA helicopter VGHN recorders, represent 813 flights or 359 flying hours, and are compared where applicable to previous survey results. The current survey results show that none of the helicopters exceeded the maximum design airspeed. One military helicopter, used for instrument flight training, never exceeded 70 percent of its maximum design airspeed. The rates of climb and descent utilized by the IFR training helicopter and of the mountain-based helicopter were generally narrowly distributed within all the airspeed ranges. The number of landings per hour for all four of the helicopters ranged from 1.6 to 3.3. The turbine-engine helicopter experienced more frequent normal-acceleration increments above a threshold of +/-0.4g (where g is acceleration due to gravity) than the mountain-based helicopter, but the mountain-based helicopter experienced acceleration increments of greater magnitude. Limited rotor rotational speed time histories showed that all the helicopters were operated at normal rotor speeds during all flight conditions.

  13. Measures for simulator evaluation of a helicopter obstacle avoidance system

    NASA Technical Reports Server (NTRS)

    Demaio, Joe; Sharkey, Thomas J.; Kennedy, David; Hughes, Micheal; Meade, Perry

    1993-01-01

    The U.S. Army Aeroflightdynamics Directorate (AFDD) has developed a high-fidelity, full-mission simulation facility for the demonstration and evaluation of advanced helicopter mission equipment. The Crew Station Research and Development Facility (CSRDF) provides the capability to conduct one- or two-crew full-mission simulations in a state-of-the-art helicopter simulator. The CSRDF provides a realistic, full field-of-regard visual environment with simulation of state-of-the-art weapons, sensors, and flight control systems. We are using the CSRDF to evaluate the ability of an obstacle avoidance system (OASYS) to support low altitude flight in cluttered terrain using night vision goggles (NVG). The OASYS uses a laser radar to locate obstacles to safe flight in the aircraft's flight path. A major concern is the detection of wires, which can be difficult to see with NVG, but other obstacles--such as trees, poles or the ground--are also a concern. The OASYS symbology is presented to the pilot on a head-up display mounted on the NVG (NVG-HUD). The NVG-HUD presents head-stabilized symbology to the pilot while allowing him to view the image intensified, out-the-window scene through the HUD. Since interference with viewing through the display is a major concern, OASYS symbology must be designed to present usable obstacle clearance information with a minimum of clutter.

  14. ALLFlight: multisensor data fusion for helicopter operations

    NASA Astrophysics Data System (ADS)

    Doehler, H.-U.; Lueken, T.

    2010-04-01

    The objective of the project ALLFlight (Assisted Low Level Flight and Landing on Unprepared Landing Sites) is to demonstrate and evaluate the characteristics of different sensors for helicopter operations within degraded visual environments, such as brownout or whiteout. The sensor suite, which is mounted onto DLR's research helicopter EC135 consists of standard color or black and white TV cameras, an un-cooled thermal infrared camera (EVS-1000, Max-Viz, USA), an optical radar scanner (HELLAS-W, EADS, Germany; a millimeter wave radar system (AI-130, ICx Radar Systems, Canada). Data processing is designed and realized by a sophisticated, high performance sensor co-computer (SCC) cluster architecture, which is installed into the helicopter's experimental electronic cargo bay. This paper describes applied methods and the software architecture in terms of real time data acquisition, recording, time stamping and sensor data fusion. First concepts for a pilot HMI are presented as well.

  15. A comprehensive plan for helicopter drag reduction

    NASA Technical Reports Server (NTRS)

    Williams, R. M.; Montana, P. S.

    1975-01-01

    Current helicopters have parasite drag levels 6 to 10 times as great as fixed wing aircraft. The commensurate poor cruise efficiency results in a substantial degradation of potential mission capability. The paper traces the origins of helicopter drag and shows that the problem (primarily due to bluff body flow separation) can be solved by the adoption of a comprehensive research and development plan. This plan, known as the Fuselage Design Methodology, comprises both nonaerodynamic and aerodynamic aspects. The aerodynamics are discussed in detail and experimental and analytical programs are described which will lead to a solution of the bluff body problem. Some recent results of work conducted at the Naval Ship Research and Development Center (NSRDC) are presented to illustrate these programs. It is concluded that a 75-per cent reduction of helicopter drag is possible by the full implementation of the Fuselage Design Methodology.

  16. Role of helicopters in airport access

    NASA Technical Reports Server (NTRS)

    Dajani, J. S.; Snyder, W. J.

    1978-01-01

    The paper briefly reviews the role of helicopter systems in the provision of airport access services and evaluates the potential for the future development of such services in major metropolitan areas in the United States. The evaluation is based on a computer simulation of potential helicopter system proposed for 20 metropolitan areas. The simulation provides two indicators that are used to gage the extent of the feasibility of developing successful systems in these areas: (1) the cost per seat mile, and (2) the break-even number of passengers, expressed as a percentage of total air travelers. It is found that a few metropolitan areas presently have the potential of marginally supporting intra-urban helicopter airport access service. The access systems offer a viable alternative for air passengers placing a high value on their time, and provides the opportunity for better integrating the air transportation service of multiple airports in a given urban region.

  17. Helicopter tail rotor orthogonal blade vortex interaction

    NASA Astrophysics Data System (ADS)

    Coton, F. N.; Marshall, J. S.; Galbraith, R. A. McD.; Green, R. B.

    2004-10-01

    The aerodynamic operating environment of the helicopter is particularly complex and, to some extent, dominated by the vortices trailed from the main and tail rotors. These vortices not only determine the form of the induced flow field but also interact with each other and with elements of the physical structure of the flight vehicle. Such interactions can have implications in terms of structural vibration, noise generation and flight performance. In this paper, the interaction of main rotor vortices with the helicopter tail rotor is considered and, in particular, the limiting case of the orthogonal interaction. The significance of the topic is introduced by highlighting the operational issues for helicopters arising from tail rotor interactions. The basic phenomenon is then described before experimental studies of the interaction are presented. Progress in numerical modelling is then considered and, finally, the prospects for future research in the area are discussed.

  18. A critical care helicopter system in trauma.

    PubMed Central

    Jacobs, L. M.; Bennett, B.

    1989-01-01

    Civilian helicopters and emergency medical services in the United States have been in existence for approximately 15 years. The rapid growth of this type of health care delivery coupled with an increasing number of accidents has prompted professional and lay scrutiny of these programs. Although they have a demonstrated history of benefit to patients, the type and severity of injuries to patients who are eligible for helicopter transportation need further definition. The composition of the medical crews and the benefits that particular crew members bring to the patients require ongoing evaluation. Significant questions regarding the number of pilots in a helicopter and in a program remain to be answered. This article reviews the role of emergency medical air transport services in providing care to trauma patients, staff training and evaluation, and safety criteria and offers recommendations to minimize risks to patients and crews. PMID:2695653

  19. Minimum-complexity helicopter simulation math model

    NASA Technical Reports Server (NTRS)

    Heffley, Robert K.; Mnich, Marc A.

    1988-01-01

    An example of a minimal complexity simulation helicopter math model is presented. Motivating factors are the computational delays, cost, and inflexibility of the very sophisticated math models now in common use. A helicopter model form is given which addresses each of these factors and provides better engineering understanding of the specific handling qualities features which are apparent to the simulator pilot. The technical approach begins with specification of features which are to be modeled, followed by a build up of individual vehicle components and definition of equations. Model matching and estimation procedures are given which enable the modeling of specific helicopters from basic data sources such as flight manuals. Checkout procedures are given which provide for total model validation. A number of possible model extensions and refinement are discussed. Math model computer programs are defined and listed.

  20. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Rich, M. J.; Lowry, D. W.

    1985-01-01

    An assessment of composite helicopter structures, exposed to environmental effects, after four years of commercial service is presented. This assessment is supported by test results of helicopter components and test panels which have been exposed to environmental effects since late 1979. Full scale static and fatigue tests are being conducted on composite components obtained from S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale tests are being conducted on coupons obtained from panels being exposed to outdoor conditions in Stratford, Connecticut and West Palm Beach, Florida. The panel layups represent S-76 components. Moisture evaluations and strength tests are being conducted, on the S-76 components and panels, over a period of eight years. Results are discussed for components and panels with up to four years of exposure.

  1. Neuro-optimal control of helicopter UAVs

    NASA Astrophysics Data System (ADS)

    Nodland, David; Ghosh, Arpita; Zargarzadeh, H.; Jagannathan, S.

    2011-05-01

    Helicopter UAVs can be extensively used for military missions as well as in civil operations, ranging from multirole combat support and search and rescue, to border surveillance and forest fire monitoring. Helicopter UAVs are underactuated nonlinear mechanical systems with correspondingly challenging controller designs. This paper presents an optimal controller design for the regulation and vertical tracking of an underactuated helicopter using an adaptive critic neural network framework. The online approximator-based controller learns the infinite-horizon continuous-time Hamilton-Jacobi-Bellman (HJB) equation and then calculates the corresponding optimal control input that minimizes the HJB equation forward-in-time. In the proposed technique, optimal regulation and vertical tracking is accomplished by a single neural network (NN) with a second NN necessary for the virtual controller. Both of the NNs are tuned online using novel weight update laws. Simulation results are included to demonstrate the effectiveness of the proposed control design in hovering applications.

  2. Helicopter impulsive noise - Theoretical and experimental status

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.; Yu, Y. H.

    1986-01-01

    The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanism is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanism of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.

  3. Helicopter impulsive noise: Theoretical and experimental status

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.; Yu, Y. H.

    1983-01-01

    The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanism is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanism of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory-experiment are suggested.

  4. Helicopter impulsive noise - Theoretical and experimental status

    NASA Technical Reports Server (NTRS)

    Schmitz, F. H.; Yu, Y. H.

    1986-01-01

    The theoretical and experimental status of helicopter impulsive noise is reviewed. The two major source mechanisms of helicopter impulsive noise are addressed: high-speed impulsive noise and blade-vortex interaction impulsive noise. A thorough physical explanation of both generating mechanisms is presented together with model and full-scale measurements of the phenomena. Current theoretical prediction methods are compared with experimental findings of isolated rotor tests. The noise generating mechanisms of high speed impulsive noise are fairly well understood - theory and experiment compare nicely over Mach number ranges typical of today's helicopters. For the case of blade-vortex interaction noise, understanding of noise generating mechanisms and theoretical comparison with experiment are less satisfactory. Several methods for improving theory/experiment are suggested.

  5. Validation of helicopter noise prediction techniques

    NASA Technical Reports Server (NTRS)

    Succi, G. P.

    1981-01-01

    The current techniques of helicopter rotor noise prediction attempt to describe the details of the noise field precisely and remove the empiricisms and restrictions inherent in previous methods. These techniques require detailed inputs of the rotor geometry, operating conditions, and blade surface pressure distribution. The purpose of this paper is to review those techniques in general and the Farassat/Nystrom analysis in particular. The predictions of the Farassat/Nystrom noise computer program, using both measured and calculated blade surface pressure data, are compared to measured noise level data. This study is based on a contract from NASA to Bolt Beranek and Newman Inc. with measured data from the AH-1G Helicopter Operational Loads Survey flight test program supplied by Bell Helicopter Textron.

  6. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Mardoian, G. H.; Ezzo, M. B.

    1986-01-01

    This report presents an assessment of composite helicopter tail rotor spars and horizontal stabilizers, exposed to the effects of the environment, after up to five and a half years of commercial service. This evaluation is supported by test results of helicopter components and panels which have been exposed to outdoor environmental effects since September 1979. Full scale static and fatigue tests have been conducted on graphite/epoxy and Kevlar/epoxy composite components obtained from Sikorsky Model S-76 helicopters in commercial operations in the Gulf Coast region of Louisiana. Small scale static and fatigue tests are being conducted on coupons obtained from panels under exposure to outdoor conditions in Stratford, Connecticut and West Palm, Florida. The panel layups are representative of the S-76 components. Additionally, this report discusses the results of moisture absorption evaluations and strength tests on the S-76 components and composite panels with up to five years of outdoor exposure.

  7. Signs of a Heart Attack

    MedlinePlus

    ... attack Heart Health and Stroke Signs of a heart attack Related information Make the Call. Don't Miss ... to top More information on Signs of a heart attack Read more from womenshealth.gov Make the Call, ...

  8. Rotor Performance at High Advance Ratio: Theory versus Test

    NASA Technical Reports Server (NTRS)

    Harris, Franklin D.

    2008-01-01

    Five analytical tools have been used to study rotor performance at high advance ratio. One is representative of autogyro rotor theory in 1934 and four are representative of helicopter rotor theory in 2008. The five theories are measured against three sets of well documented, full-scale, isolated rotor performance experiments. The major finding of this study is that the decades spent by many rotorcraft theoreticians to improve prediction of basic rotor aerodynamic performance has paid off. This payoff, illustrated by comparing the CAMRAD II comprehensive code and Wheatley & Bailey theory to H-34 test data, shows that rational rotor lift to drag ratios are now predictable. The 1934 theory predicted L/D ratios as high as 15. CAMRAD II predictions compared well with H-34 test data having L/D ratios more on the order of 7 to 9. However, the detailed examination of the selected codes compared to H-34 test data indicates that not one of the codes can predict to engineering accuracy above an advance ratio of 0.62 the control positions and shaft angle of attack required for a given lift. There is no full-scale rotor performance data available for advance ratios above 1.0 and extrapolation of currently available data to advance ratios on the order of 2.0 is unreasonable despite the needs of future rotorcraft. Therefore, it is recommended that an overly strong full-scale rotor blade set be obtained and tested in a suitable wind tunnel to at least an advance ratio of 2.5. A tail rotor from a Sikorsky CH-53 or other large single rotor helicopter should be adequate for this exploratory experiment.

  9. Ground Shake Test of the Boeing Model 360 Helicopter Airframe

    NASA Technical Reports Server (NTRS)

    Reed, D. A.; Gabel, R.

    1989-01-01

    Boeing Helicopters, together with other U.S. Helicopter manufacturers, is engaged in a finite element applications program designed to emplace in the U.S. a superior capability to utilize finite element analysis models in support of helicopter airframe structurel design. This program was given the acronym DAMVIBS (Design Analysis Methods for VIBrationS). The test plan is reviewed and results are presented for a shake test of the Boeing Model 360 helicopter. Results of the test will serve as the basis for validation of a finite element vibration model of the helicopter.

  10. The effect of a helicopter on DC fields and ions

    SciTech Connect

    Harris, E.L. ); Rindall, B.D.; Tarko, N.J. ); Norris-Elye, O.C. )

    1993-10-01

    When a plan was initiated to utilize a helicopter to perform work on an energized, high voltage dc transmission line by bonding the helicopter to the conductor, it was necessary to determine what effect, if any, the helicopter would have on the dc fields and ions. In addition, it was necessary to determine the possible effect on helicopter instrumentation and communications. A test site and research facility at Lundar, Manitoba, Canada, provided the ideal location for making these tests. As a result, the information obtained determined that a helicopter-airborne platform could safely be used to perform the work.

  11. Effect of planform taper on hover performance of an advanced AH-64 model rotor

    NASA Technical Reports Server (NTRS)

    Kelley, Henry L.

    1987-01-01

    The hover performance of a 27 percent scale model baseline rotor and advanced rotor with a 3:1 tapered tip (TR3) for the AH-64 attack helicopter was investigated and compared. Hover results from a previously tested advanced rotor with a 5:1 tapered tip (TR5) were also compared. Rotor thrust was varied over a range for two tip Mach numbers. The results indicated that the TR3 blades had improved performance compared with the TR5 blades, and both the TR3 and TR5 blades were superior to the baseline rotor. The additional margin in performance for the TR3 blades was likely due to an increase in blade area and Reynolds number in the tip region of the blades.

  12. Full-Scale Crash Test and Finite Element Simulation of a Composite Prototype Helicopter

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.; Boitnott, Richard L.; Lyle, Karen H.

    2003-01-01

    A full-scale crash test of a prototype composite helicopter was performed at the Impact Dynamics Research Facility at NASA Langley Research Center in 1999 to obtain data for validation of a finite element crash simulation. The helicopter was the flight test article built by Sikorsky Aircraft during the Advanced Composite Airframe Program (ACAP). The composite helicopter was designed to meet the stringent Military Standard (MIL-STD-1290A) crashworthiness criteria and was outfitted with two crew and two troop seats and four anthropomorphic dummies. The test was performed at 38-ft/s vertical and 32.5-ft/s horizontal velocity onto a rigid surface. An existing modal-vibration model of the Sikorsky ACAP helicopter was converted into a model suitable for crash simulation. A two-stage modeling approach was implemented and an external user-defined subroutine was developed to represent the complex landing gear response. The crash simulation was executed with a nonlinear, explicit transient dynamic finite element code. Predictions of structural deformation and failure, the sequence of events, and the dynamic response of the airframe structure were generated and the numerical results were correlated with the experimental data to validate the simulation. The test results, the model development, and the test-analysis correlation are described.

  13. Contingency power concepts for helicopter turboshaft engine

    NASA Technical Reports Server (NTRS)

    Hirschkron, R.; Davis, R. H.; Goldstein, D. N.; Haynes, J. F.; Gauntner, J. W.

    1984-01-01

    Twin helicopter engines are often sized by power requirement of safe mission completion after the failure of one of the two engines. This study was undertaken for NASA Lewis by General Electric Co. to evaluate the merits of special design features to provide a 2-1/2 minute Contingency Power rating, permitting an engine size reduction. The merits of water injection, cooling flow modulation, throttle push and an auxiliary power plant were evaluated using military life cycle cost (LCC) and commercial helicopter direct operating cost (DOC) merit factors in a rubber engine/rubber aircraft scenario.

  14. Helicopter trajectory planning using optimal control theory

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1988-01-01

    A methodology for optimal trajectory planning, useful in the nap-of-the-earth guidance of helicopters, is presented. This approach uses an adjoint-control transformation along with a one-dimensional search scheme for generating the optimal trajectories. In addition to being useful for helicopter nap-of-the-earth guidance, the trajectory planning solution is of interest in several other contexts, such as robotic vehicle guidance and terrain-following guidance for cruise missiles and aircraft. A distinguishing feature of the present research is that the terrain constraint and the threat envelopes are incorporated in the equations of motion. Second-order necessary conditions are examined.

  15. Antitank missiles night firing from Aerospatiale helicopters

    NASA Astrophysics Data System (ADS)

    Dewinter, G.

    A day/night firing system for HOT antitank missiles was developed and mounted on a HAC/PAH2 helicopter, equipped with a suitably adapted sight. Night fighting requirements for a helicopter that is armed with antitank missiles are recalled. The selection of a sensor is discussed. The design of a platform in order to fulfill the observation and firing mission is described. Night antitank action is analyzed. Characteristics of a thermal imager which solves the identified problems of night firing are given.

  16. Efficient fault diagnosis of helicopter gearboxes

    NASA Astrophysics Data System (ADS)

    Chin, H.; Danai, K.; Lewicki, D. G.

    1993-07-01

    Application of a diagnostic system to a helicopter gearbox is presented. The diagnostic system is a nonparametric pattern classifier that uses a multi-valued influence matrix (MVIM) as its diagnostic model and benefits from a fast learning algorithm that enables it to estimate its diagnostic model from a small number of measurement-fault data. To test this diagnostic system, vibration measurements were collected from a helicopter gearbox test stand during accelerated fatigue tests and at various fault instances. The diagnostic results indicate that the MVIM system can accurately detect and diagnose various gearbox faults so long as they are included in training.

  17. Influence of maneuverability on helicopter combat effectiveness

    NASA Technical Reports Server (NTRS)

    Falco, M.; Smith, R.

    1982-01-01

    A computational procedure employing a stochastic learning method in conjunction with dynamic simulation of helicopter flight and weapon system operation was used to derive helicopter maneuvering strategies. The derived strategies maximize either survival or kill probability and are in the form of a feedback control based upon threat visual or warning system cues. Maneuverability parameters implicit in the strategy development include maximum longitudinal acceleration and deceleration, maximum sustained and transient load factor turn rate at forward speed, and maximum pedal turn rate and lateral acceleration at hover. Results are presented in terms of probability of skill for all combat initial conditions for two threat categories.

  18. Obstacle-warning radar for helicopters

    NASA Astrophysics Data System (ADS)

    Och, G. M.

    An obstacle warning radar concept for helicopters is described in both the test and operational phases. A radar sonde is mounted on the front of the helicopter under a radome and senses the atmosphere forward over a range of 180 deg azimuth and 32 deg elevation. The ray is directed by a fast-rotating mirror, resulting in an image-renewal rate of two per second. Obstacles can be detected to a distance of 800 m. depending on atmospheric conditions and obstacle size.

  19. Efficient fault diagnosis of helicopter gearboxes

    NASA Technical Reports Server (NTRS)

    Chin, H.; Danai, K.; Lewicki, D. G.

    1993-01-01

    Application of a diagnostic system to a helicopter gearbox is presented. The diagnostic system is a nonparametric pattern classifier that uses a multi-valued influence matrix (MVIM) as its diagnostic model and benefits from a fast learning algorithm that enables it to estimate its diagnostic model from a small number of measurement-fault data. To test this diagnostic system, vibration measurements were collected from a helicopter gearbox test stand during accelerated fatigue tests and at various fault instances. The diagnostic results indicate that the MVIM system can accurately detect and diagnose various gearbox faults so long as they are included in training.

  20. Coaxial Compound Helicopter for Confined Urban Operations

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Elmore, Joshua F.; Keen, Ernest B.; Gallaher, Andrew T.; Nunez, Gerardo F.

    2016-01-01

    A rotorcraft was designed for military operations in a confined urban environment. The specifications included major increases in useful load, range, and speed relative current aircraft capabilities, with a size constraint based on the dimensions of urban streets and intersections. Analysis showed that this combination of requirements is best satisfied by a coaxial main-rotor configuration, with lift compounding to off-load the rotors at high speed, and ducted fans under the rotor disk for propulsion. The baseline design is described, and the aircraft performance is summarized for utility, attack, MEDEVAC, and cargo delivery missions. The impact on size and performance is examined for a number of excursions, including lift-offset main rotors. Technology development required to achieve this advance in capability is recommended.

  1. A fatal leopard attack.

    PubMed

    Hejna, Petr

    2010-05-01

    A rare case of a big cat fatal attack is presented. A male leopard that had escaped from its unlocked cage attacked a 26-year-old male zoo worker. The man sustained penetrating injuries to the neck with consequent external bleeding. The man died while being transported to the hospital as a result of the injuries sustained. The wounds discovered on the victim's body corresponded with the known methods of leopard attacks and with findings on the carcasses of animals killed by leopards in the wild. The conclusion of the medicolegal investigation was that the underlying cause of death was a bite wound to the neck which lacerated the left internal jugular vein, the two main branches of the left external carotid artery, and the cervical spine. The cause of death was massive external bleeding. Special attention is paid to the general pattern of injuries sustained from big cat attacks.

  2. Heart attack first aid

    MedlinePlus

    First aid - heart attack; First aid - cardiopulmonary arrest; First aid - cardiac arrest ... of patients with unstable angina/non-ST-elevation myocardial infarction (updating the 2007 guideline and replacing the 2011 ...

  3. Mach number scaling of helicopter rotor blade/vortex interaction noise

    NASA Technical Reports Server (NTRS)

    Leighton, Kenneth P.; Harris, Wesley L.

    1985-01-01

    A parametric study of model helicopter rotor blade slap due to blade vortex interaction (BVI) was conducted in a 5 by 7.5-foot anechoic wind tunnel using model helicopter rotors with two, three, and four blades. The results were compared with a previously developed Mach number scaling theory. Three- and four-bladed rotor configurations were found to show very good agreement with the Mach number to the sixth power law for all conditions tested. A reduction of conditions for which BVI blade slap is detected was observed for three-bladed rotors when compared to the two-bladed baseline. The advance ratio boundaries of the four-bladed rotor exhibited an angular dependence not present for the two-bladed configuration. The upper limits for the advance ratio boundaries of the four-bladed rotors increased with increasing rotational speed.

  4. Periodic control of the individual-blade-control helicopter rotor. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Mckillip, R. M., Jr.

    1984-01-01

    Results of an investigation into methods of controller design for an individual helicopter rotor blade in the high forward-flight speed regime are described. This operating condition poses a unique control problem in that the perturbation equations of motion are linear with coefficients that vary periodically with time. The design of a control law was based on extensions to modern multivariate synthesis techniques and incorporated a novel approach to the reconstruction of the missing system state variables. The controller was tested on both an electronic analog computer simulation of the out-of-plane flapping dynamics, and on a four foot diameter single-bladed model helicopter rotor in the M.I.T. 5x7 subsonic wind tunnel at high levels of advance ratio. It is shown that modal control using the IBC concept is possible over a large range of advance ratios with only a modest amount of computational power required.

  5. 78 FR 37152 - Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... FR 11034, February 26, 1979); ] 3. Will not affect intrastate aviation in Alaska to the extent that... Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4; telephone (450)...

  6. Aerodynamic interactions between a 1/6 scale helicopter rotor and a body of revolution

    NASA Technical Reports Server (NTRS)

    Betzina, M. D.; Shinoda, P.

    1982-01-01

    A wind-tunnel investigation was conducted in which independent, steady state aerodynamic forces and moments were measured on a 2.24-m-diam, two bladed helicopter rotor and a body of revolution. The objective was to determine the interaction of the body on the rotor performance and the effect of the rotor on the body aerodynamics for variations in velocity, thrust, tip-path-plane angle of attack, body angle of attack, rotor/body position, and body nose geometry. Results show that a body of revolution near the rotor can produce significant favorable or unfavorable effects on rotor performance, depending on the operating condition. Body longitudinal aerodynamic characteristics are significantly modified by the presence of an operating rotor and hub.

  7. CASE STUDY: DIELDRIN ATTACK IN DALYAN LAGOON

    EPA Science Inventory

    During the first two weeks of December 2005, NATO sponsored an Advanced Study Institute (ASI) in Istanbul, Turkey. Part of this ASI involved a case study of a terrorist attack, where a chemical was assumed to be dumped into Sulunger Lake in Turkey. This chapter documents the re...

  8. Helicopter-based live-line work. Volume 1, Helicopter platform work between phases: Final report

    SciTech Connect

    Gela, G.

    1993-06-01

    This report presents experimental data on tests of a configuration consisting of a helicopter between two energized phases (for AC and switching surge) or poles (for DC). The configuration is that related to live-line work from a hovering helicopter. The McDonnell Douglas 500 Series helicopter was used for the tests. All tests were performed with phase-to-phase, or pole-to-pole energization. For AC tests, proper relationship between the phase-to-ground voltages and the phase-to-phase voltage was maintained by energizing the experimental setup from a balanced 3-{phi} AC source. For DC tests, one pole was energized with positive DC voltage to ground, while the other pole was energized with negative DC voltage to ground. For switching surge tests, a surge of positive polarity and a specific peak voltage magnitude was applied to one phase while a surge of negative polarity and the same peak voltage Magnitude was simultaneously applied to the other phase, resulting in {alpha} = 0.5 ({alpha} is the ratio between negative and total surge). In the research program, four conditions were investigated, namely helicopter operating versus not operating, and helicopter bonded to one phase or pole versus not bonded. Results from this research show effects of the rotating main rotor blade of the helicopter, effect of the position of the electrically floating helicopter in the phase-to-phase or pole-to-pole gap, effects of the mannequin, importance of the polarity of the DC poles and switching surges, and effects of inclement weather such as rain. The overall conclusion of this research is that the phase-to-phase or pole-to-pole spacings that cause sparkover with the helicopter between phases (poles) were always significantly smaller than the typical spacings on actual existing overhead transmission lines of the corresponding voltage rating.

  9. McDonnell Douglas Helicopter Company independent research and development: Preparing for the future

    NASA Technical Reports Server (NTRS)

    Haggerty, Allen C.

    1988-01-01

    During the 1970's and 80's, research has produced the technology that is seen in aircraft such as the LHX and future models. The technology is discussed that is reaching maturity and moving into the application stage of future programs. Technology is discussed in six major areas: advanced concepts, analysis techniques, structures, systems, simulation, and research and development facilities. The partnership of McDonnell Douglas Helicopter Co. and the government in developing these technologies is illustrated in several programs.

  10. Study Of Helicopter-Tail-Rotor Noise

    NASA Technical Reports Server (NTRS)

    Ahmadi, Ali R.; Beranek, Bolt

    1988-01-01

    Report describes findings of experiment in generation of impulsive noise and fluctuating blade loads by helicopter tail rotor interacting with vortexes from main rotor. Experiment used model rotor and isolated vortex and designed to isolate blade/vortex interaction noise from other types of rotor noise.

  11. Considerations of Methods of Improving Helicopter Efficiency

    NASA Technical Reports Server (NTRS)

    Dingeldein, Richard C.

    1961-01-01

    Recent NASA helicopter research indicates that significant improvements in hovering efficiency, up to 7 percent, are available from the use of a special airfoil section formed by combining an NACA 632A015 thickness distribution with an NACA 230 mean line. This airfoil should be considered for flying-crane-type helicopters. Application of standard leading-edge roughness causes a large drop in efficiency; however, the cambered rotor is shown to retain its superiority over a rotor having a symmetrical airfoil when both rotors have leading-edge roughness. A simple analysis of available rotor static-thrust data indicates a greatly reduced effect of compressibility effects on the rotor profile-drag power than predicted from calculations. Preliminary results of an experimental study of helicopter parasite drag indicate the practicability of achieving an equivalent flat-plate parasite-drag area of less than 4 square feet for a rotor-head-pylon-fuselage configuration (landing gear retracted) in the 2,000-pound minimum-flying-weight class. The large drag penalty of a conventional skid-type landing (3.6 square feet) can be reduced by two-thirds by careful design. Clean, fair, and smooth fuselages that tend to have narrow, deep cross sections are shown to have advantages from the standpoint of drag and download. A ferry range of the order of 1,500 miles is indicated to be practicable for the small helicopter considered.

  12. Helicopter Parents Can Be a Good Thing

    ERIC Educational Resources Information Center

    Hiltz, Julie

    2015-01-01

    Helicopter parents get a bad rap. Teachers and administrators should view them as a resource--not a nuisance. By encouraging open communication, teachers can begin to understand the motivations of these parents and find creative ways to connect them with opportunities to promote their students' academic success and the school's overall…

  13. Helicopter Parents Help Students, Survey Finds

    ERIC Educational Resources Information Center

    Lipka, Sara

    2007-01-01

    Helicopter parents, notorious for hovering over their college-age children, may actually help students thrive, according to this year's National Survey of Student Engagement. Students whose parents intervene on their behalf--38 percent of freshmen and 29 percent of seniors--are more active in and satisfied with college, says the monstrous annual…

  14. Performance Measurement in Helicopter Training and Operations.

    ERIC Educational Resources Information Center

    Prophet, Wallace W.

    For almost 15 years, HumRRO Division No. 6 has conducted an active research program on techniques for measuring the flight performance of helicopter trainees and pilots. This program addressed both the elemental aspects of flying (i.e., maneuvers) and the mission- or goal-oriented aspects. A variety of approaches has been investigated, with the…

  15. An airborne sunphotometer for use with helicopters

    SciTech Connect

    Walthall, C.L.; Halthore, R.N.; Elman, G.C.; Schafer, J.R.; Markham, B.L.

    1996-04-01

    One solution for atmospheric correction and calibration of remotely sensed data from airborne platforms is the use of radiometrically calibrated instruments, sunphotometers and an atmospheric radiative transfer model. Sunphotometers are used to measure the direct solar irradiance at the level at which they are operating and the data are used in the computation of atmospheric optical depth. Atmospheric optical depth is an input to atmospheric correction algorithms that convert at-sensor radiance to required surface properties such as reflectance and temperature. Airborne sun photometry has thus far seen limited use and has not been used with a helicopter platform. The hardware, software, calibration and deployment of an automatic sun-tracking sunphotometer specifically designed for use on a helicopter are described. Sample data sets taken with the system during the 1994 Boreal Ecosystem and Atmosphere Study (BOREAS) are presented. The addition of the sun photometer to the helicopter system adds another tool for monitoring the environment and makes the helicopter remote sensing system capable of collecting calibrated, atmospherically corrected data independent of the need for measurements from other systems.

  16. Helicopter rotor trailing edge noise. [noise prediction

    NASA Technical Reports Server (NTRS)

    Schlinker, R. H.; Amier, R. K.

    1981-01-01

    A two dimensional section of a helicopter main rotor blade was tested in an acoustic wind tunnel at close to full-scale Reynolds numbers to obtain boundary layer data and acoustic data for use in developing an acoustic scaling law and testing a first principles trailing edge noise theory. Results were extended to the rotating frame coordinate system to develop a helicopter rotor trailing edge noise prediction. Comparisons of the calculated noise levels with helicopter flyover spectra demonstrate that trailing edge noise contributes significantly to the total helicopter noise spectrum at high frequencies. This noise mechanism is expected to control the minimum rotor noise. In the case of noise radiation from a local blade segment, the acoustic directivity pattern is predicted by the first principles trailing edge noise theory. Acoustic spectra are predicted by a scaling law which includes Mach number, boundary layer thickness and observer position. Spectrum shape and sound pressure level are also predicted by the first principles theory but the analysis does not predict the Strouhal value identifying the spectrum peak.

  17. Defibrillation safety in emergency helicopter transport.

    PubMed

    Dedrick, D K; Darga, A; Landis, D; Burney, R E

    1989-01-01

    Rotary aircraft play a growing role in the transport of critically ill patients who may require emergency treatment, including defibrillation, during transport. The close quarters and proximity of vital electronic equipment have generated concern among personnel carrying out defibrillation in the air. We address the chief safety issues in helicopter defibrillation by providing measurements of the transient leakage current resulting from contact with a paddle and tested in-flight electronic interference and survey the defibrillation experience of helicopter programs. Our data show that airborne defibrillation is safe. A maximum of 1.5 mA of transient leakage current was measured from a standard battery-powered defibrillator, well within the accepted safety standard of 50 mA. In flight, there was no interference with the avionics or medical equipment, and adequate clearance was available for personnel. Of the helicopter programs surveyed, 69 (87%) had defibrillated in flight without incident. We conclude that defibrillation can be performed in the helicopter without hesitation whether on the ground or in the air, provided standard defibrillation precautions are observed.

  18. 46 CFR 109.577 - Helicopter fueling.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS... subparts 98.30 and 98.33 of this chapter and the provisions of 49 CFR parts 171 through 179 that apply...

  19. 46 CFR 109.577 - Helicopter fueling.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS... subparts 98.30 and 98.33 of this chapter and the provisions of 49 CFR parts 171 through 179 that apply...

  20. 46 CFR 109.577 - Helicopter fueling.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS... subparts 98.30 and 98.33 of this chapter and the provisions of 49 CFR parts 171 through 179 that apply...

  1. 46 CFR 109.577 - Helicopter fueling.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS... subparts 98.30 and 98.33 of this chapter and the provisions of 49 CFR parts 171 through 179 that apply...

  2. 46 CFR 109.577 - Helicopter fueling.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Helicopter fueling. 109.577 Section 109.577 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) A-MOBILE OFFSHORE DRILLING UNITS OPERATIONS... subparts 98.30 and 98.33 of this chapter and the provisions of 49 CFR parts 171 through 179 that apply...

  3. Flight service evaluation of composite components on the Bell Helicopter model 206L: Design, fabrication and testing

    NASA Technical Reports Server (NTRS)

    Zinberg, H.

    1982-01-01

    The design, fabrication, and testing phases of a program to obtain long term flight service experience on representative helicopter airframe structural components operating in typical commercial environments are described. The aircraft chosen is the Bell Helicopter Model 206L. The structural components are the forward fairing, litter door, baggage door, and vertical fin. The advanced composite components were designed to replace the production parts in the field and were certified by the FAA to be operable through the full flight envelope of the 206L. A description of the fabrication process that was used for each of the components is given. Static failing load tests on all components were done. In addition fatigue tests were run on four specimens that simulated the attachment of the vertical fin to the helicopter's tail boom.

  4. CFD Based Computations of Flexible Helicopter Blades for Stability Analysis

    NASA Technical Reports Server (NTRS)

    Guruswamy, Guru P.

    2011-01-01

    As a collaborative effort among government aerospace research laboratories an advanced version of a widely used computational fluid dynamics code, OVERFLOW, was recently released. This latest version includes additions to model flexible rotating multiple blades. In this paper, the OVERFLOW code is applied to improve the accuracy of airload computations from the linear lifting line theory that uses displacements from beam model. Data transfers required at every revolution are managed through a Unix based script that runs jobs on large super-cluster computers. Results are demonstrated for the 4-bladed UH-60A helicopter. Deviations of computed data from flight data are evaluated. Fourier analysis post-processing that is suitable for aeroelastic stability computations are performed.

  5. Aeroelastic model helicopter rotor testing in the Langley TDT

    NASA Technical Reports Server (NTRS)

    Mantay, W. R.; Yeager, W. T., Jr.; Hamouda, M. N.; Cramer, R. G., Jr.; Langston, C. W.

    1985-01-01

    Wind-tunnel testing of a properly scaled aeroelastic model helicopter rotor is considered a necessary phase in the design development of new or existing rotor systems. For this reason, extensive testing of aeroelastically scaled model rotors is done in the Transonic Dynamics Tunnel (TDT) located at the NASA Langley Research Center. A unique capability of this facility, which enables proper dynamic scaling, is the use of Freon as a test medium. A description of the TDT and a discussion of the benefits of using Freon as a test medium are presented. A description of the model test bed used, the Aeroelastic Rotor Experimental System (ARES), is also provided and examples of recent rotor tests are cited to illustrate the advantages and capabilities of aeroelastic model rotor testing in the TDT. The importance of proper dynamic scaling in identifying and solving rotorcraft aeroelastic problems, and the importance of aeroelastic testing of model rotor systems in the design of advanced rotor systems are demonstrated.

  6. Helicopter rotor and engine sizing for preliminary performance estimation

    NASA Technical Reports Server (NTRS)

    Talbot, P. D.; Bowles, J. V.; Lee, H. C.

    1986-01-01

    Methods are presented for estimating some of the more fundamental design variables of single-rotor helicopters (tip speed, blade area, disk loading, and installed power) based on design requirements (speed, weight, fuselage drag, and design hover ceiling). The well-known constraints of advancing-blade compressibility and retreating-blade stall are incorporated into the estimation process, based on an empirical interpretation of rotor performance data from large-scale wind-tunnel tests. Engine performance data are presented and correlated with a simple model usable for preliminary design. When approximate results are required quickly, these methods may be more convenient to use and provide more insight than large digital computer programs.

  7. Collaborative Attack vs. Collaborative Defense

    NASA Astrophysics Data System (ADS)

    Xu, Shouhuai

    We have witnessed many attacks in the cyberspace. However, most attacks are launched by individual attackers even though an attack may involve many compromised computers. In this paper, we envision what we believe to be the next generation cyber attacks — collaborative attacks. Collaborative attacks can be launched by multiple attackers (i.e., human attackers or criminal organizations), each of which may have some specialized expertise. This is possible because cyber attacks can become very sophisticated and specialization of attack expertise naturally becomes relevant. To counter collaborative attacks, we might need collaborative defense because each “chain” in a collaborative attack may be only adequately dealt with by a different defender. In order to understand collaborative attack and collaborative defense, we present a high-level abstracted framework for evaluating the effectiveness of collaborative defense against collaborative attacks. As a first step towards realizing and instantiating the framework, we explore a characterization of collaborative attacks and collaborative defense from the relevant perspectives.

  8. Numerical simulation and comparison of symmetrical/supercritical airfoils for the near tip region of a helicopter in forward flight

    NASA Technical Reports Server (NTRS)

    Badavi, F. F.

    1989-01-01

    Aerodynamic loads on a multi-bladed helicopter rotor in forward flight at transonic tip conditions are calculated. The unsteady, three-dimensional, time-accurate compressible Reynolds-averaged thin layer Navier-Stokes equations are solved in a rotating coordinate system on a body-conformed, curvilinear grid of C-H topology. Detailed boundary layer and global numerical comparisons of NACA-0012 symmetrical and CAST7-158 supercritical airfoils are made under identical forward flight conditions. The rotor wake effects are modeled by applying a correction to the geometric angle of attack of the blade. This correction is obtained by computing the local induced downwash velocity with a free wake analysis program. The calculations are performed on the Numerical Aerodynamic Simulation Cray 2 and the VPS32 (a derivative of a Cyber 205 at the Langley Research Center) for a model helicopter rotor in forward flight.

  9. Shark attack in Natal.

    PubMed

    White, J A

    1975-02-01

    The injuries in 5 cases of shark attack in Natal during 1973-74 are reviewed. Experience in shark attacks in South Africa during this period is discussed (1965-73), and the value of protecting heavily utilized beaches in Natal with nets is assessed. The surgical applications of elasmobranch research at the Oceanographic Research Institute (Durban) and at the Headquarters of the Natal Anti-Shark Measures Board (Umhlanga Rocks) are described. Modern trends in the training of surf life-guards, the provision of basic equipment for primary resuscitation of casualties on the beaches, and the policy of general and local care of these patients in Natal are discussed.

  10. Helicopter Control Energy Reduction Using Moving Horizontal Tail.

    PubMed

    Oktay, Tugrul; Sal, Firat

    2015-01-01

    Helicopter moving horizontal tail (i.e., MHT) strategy is applied in order to save helicopter flight control system (i.e., FCS) energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC) is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA). In order to observe improvement in behaviors of classical controls closed loop analyses are done.

  11. Helicopter Control Energy Reduction Using Moving Horizontal Tail

    PubMed Central

    Oktay, Tugrul; Sal, Firat

    2015-01-01

    Helicopter moving horizontal tail (i.e., MHT) strategy is applied in order to save helicopter flight control system (i.e., FCS) energy. For this intention complex, physics-based, control-oriented nonlinear helicopter models are used. Equations of MHT are integrated into these models and they are together linearized around straight level flight condition. A specific variance constrained control strategy, namely, output variance constrained Control (i.e., OVC) is utilized for helicopter FCS. Control energy savings due to this MHT idea with respect to a conventional helicopter are calculated. Parameters of helicopter FCS and dimensions of MHT are simultaneously optimized using a stochastic optimization method, namely, simultaneous perturbation stochastic approximation (i.e., SPSA). In order to observe improvement in behaviors of classical controls closed loop analyses are done. PMID:26180841

  12. Subjective field study of response to impulsive helicopter noise

    NASA Technical Reports Server (NTRS)

    Powell, C. A.

    1981-01-01

    Subjects, located outdoors and indoors, judged the noisiness and other subjective noise characteristics of flyovers of two helicopters and a propeller driven airplane as part of a study of the effects of impulsiveness on the subjective response to helicopter noise. In the first experiment, the impulsive characteristics of one helicopter was controlled by varying the main rotor speed while maintaining a constant airspeed in level flight. The second experiment which utilized only the helicopters, included descent and level flight operations. The more impulsive helicopter was consistently judged less noisy than the less impulsive helicopter at equal effective perceived noise levels (EPNL). The ability of EPNL to predict noisiness was not improved by the addition of either of two proposed impulse corrections. A subjective measure of impulsiveness, however, which was not significantly related to the proposed impulse corrections, was found to improve the predictive ability of EPNL.

  13. A NASA helicopter arrives at KSC for painting

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The pilot of the NASA helicopter secures the rotary blade before the helicopter's transfer to Ransom Road at KSC. It is one of four UH-1H helicopters that will have its blades painted, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  14. Characterization of attacks on public telephone networks

    NASA Astrophysics Data System (ADS)

    Lorenz, Gary V.; Manes, Gavin W.; Hale, John C.; Marks, Donald; Davis, Kenneth; Shenoi, Sujeet

    2001-02-01

    The U.S. Public Telephone Network (PTN) is a massively connected distributed information systems, much like the Internet. PTN signaling, transmission and operations functions must be protected from physical and cyber attacks to ensure the reliable delivery of telecommunications services. The increasing convergence of PTNs with wireless communications systems, computer networks and the Internet itself poses serious threats to our nation's telecommunications infrastructure. Legacy technologies and advanced services encumber well-known and as of yet undiscovered vulnerabilities that render them susceptible to cyber attacks. This paper presents a taxonomy of cyber attacks on PTNs in converged environments that synthesizes exploits in computer and communications network domains. The taxonomy provides an opportunity for the systematic exploration of mitigative and preventive strategies, as well as for the identification and classification of emerging threats.

  15. Fatal crocodile attack.

    PubMed

    Chattopadhyay, Saurabh; Shee, Biplab; Sukul, Biswajit

    2013-11-01

    Attacks on human beings by various animals leading to varied types of injuries and even death in some cases are not uncommon. Crocodile attacks on humans have been reported from a number of countries across the globe. Deaths in such attacks are mostly due to mechanical injuries or drowning. Bites by the crocodiles often cause the limbs to be separated from the body. The present case refers to an incident of a fatal attack by a crocodile on a 35 years old female where only the mutilated head of the female was recovered. Multiple lacerated wounds over the face and scalp along with fracture of the cranial bones was detected on autopsy. Two distinct bite marks in the form of punched in holes were noted over the parietal and frontal bones. Injuries on the head with its traumatic amputation from the body were sufficient to cause death. However, the presence of other fatal injuries on the unrecovered body parts could not be ruled out.

  16. Word Attack Model.

    ERIC Educational Resources Information Center

    Follettie, Joseph F.

    A limited analysis of alternative approaches to phonemic-level word attack instruction is provided in this document. The instruction segment begins with training in letter-sound correspondences for which mastery of certain skills is assumed. Instruction ends with the decoding of novel items having a consonant-vowel-consonant construction. Contents…

  17. Preliminary thoughts on helicopter cabin noise prediction methods

    NASA Astrophysics Data System (ADS)

    Pollard, J. S.

    The problems of predicting helicopter cabin noise are discussed with particular reference to the Lynx helicopter. Available methods such as modal analysis adopted for propeller noise prediction do not cope with the higher frequency discrete tone content of helicopter gear noise, with the airborne and structureborne noise contributions. Statistical energy analysis methods may be the answer but until these are developed, one has to rely on classical noise transmission analysis and transfer function methods.

  18. Review of the transmissions of the Soviet helicopters

    NASA Technical Reports Server (NTRS)

    Chaiko, Lev I.

    1990-01-01

    A review of the following aspects of Soviet helicopter transmissions is presented: transmitted power, weight, reduction ratio, RPM, design configuration, comparison of different type of manufacturing methods, and a description of the materials and technologies applied to critical transmission components. Included are mechanical diagrams of the gearboxes of the Soviet helicopters and test stands for testing gearbox and main shaft. The quality of Soviet helicopter transmissions and their Western counterparts are assessed and compared.

  19. Finite difference time domain grid generation from AMC helicopter models

    NASA Technical Reports Server (NTRS)

    Cravey, Robin L.

    1992-01-01

    A simple technique is presented which forms a cubic grid model of a helicopter from an Aircraft Modeling Code (AMC) input file. The AMC input file defines the helicopter fuselage as a series of polygonal cross sections. The cubic grid model is used as an input to a Finite Difference Time Domain (FDTD) code to obtain predictions of antenna performance on a generic helicopter model. The predictions compare reasonably well with measured data.

  20. Perturbation solutions for the influence of forward flight on helicopter rotor flapping stability

    NASA Technical Reports Server (NTRS)

    Johnson, W.

    1974-01-01

    The stability of the flapping motion of a helicopter rotor blade in forward flight is investigated, using a perturbation technique which gives analytic expressions for the eigenvalues, including the influence of the periodic aerodynamic forces in forward flight. The perturbation solutions are based on small advance ratio (the ratio of the helicopter forward speed to the rotor tip speed). The rotor configurations considered are a single, independent blade; a teetering rotor; a gimballed rotor with three, four, and five or more blades; and a rotor with N independent blades. The constant coefficient approximation with the equations and degrees of freedom in the nonrotating frame represents the flap dynamic reasonably well for the lower frequency modes, although it cannot, of course, be completely correct. The transfer function of the rotor flap response to sinusoidal pitch input is examined, as an alternative to the eigenvalues as a representation of the dynamic characteristics of the flap motion.

  1. Development of circumferential seal for helicopter transmissions: Results of bench and flight tests

    NASA Technical Reports Server (NTRS)

    Strom, T. N.; Ludwig, L. P.

    1975-01-01

    A modified circumferential segmented ring seal was designed for direct replacement of a helicopter transmission elastomeric lip seal operating on a shaft diameter of 13.91 centimeters (5.481 in.) at sliding velocities to 52.48 m/sec (10 330 ft/min). The modifications involved the garter spring tension, shaft roundness, seal housing flatness, and pumping grooves to inhibit leakage. Operation of the seals in bench tests under simulated helicopter transmission conditions revealed that the seal leakage rate was within acceptable limits and that the wear rate was negligible. The low leakage and wear rates were confirmed in flight tests of 600 and 175 hours (sliding speed, 48.11 m/sec (9470 ft/min)). An additional 200 hours of air worthiness qualification testing (aircraft tie down) demonstrated that the seal can operate at the advanced sliding conditions of 52.48 m/sec (10 330 ft/min).

  2. Laser velocimeter measurements of the helicopter rotor-induced flow field

    NASA Technical Reports Server (NTRS)

    Biggers, J. C.; Orloff, K. L.

    1974-01-01

    The use of a two-color laser velocimeter to measure the flow velocities in the wake of a helicopter rotor is discussed, including methods for obtaining two components of both instantaneous and time-averaged velocities. Results are presented from an experiment using a 2.13 m diameter model helicopter rotor operating at a tip speed ratio of 0.18 in a wind tunnel. The location of the tip vortex from the preceding blade was determined on the advancing side, and the diameter of the vortex core was found to be 15 percent of the blade chord (1.5 percent of the radius). The effects of the airfoil's bound vorticity were observed in the velocity distributions vry near the blade. These effects suggest that the laser velocimeter may be used to determine the aerodynamic loading (circulation) at a spanwise station on the blade. Also, the structure and boundary of the time-averaged wake were investigated.

  3. Prediction and measurement of low-frequency harmonic noise of a hovering model helicopter rotor

    NASA Astrophysics Data System (ADS)

    Aggarawal, H. R.; Schmitz, F. H.; Boxwell, D. A.

    Far-field acoustic data for a model helicopter rotor have been gathered in a large open-jet, acoustically treated wind tunnel with the rotor operating in hover and out of ground-effect. The four-bladed Boeing 360 model rotor with advanced airfoils, planform, and tip shape was run over a range of conditions typical of today's modern helicopter main rotor. Near in-plane acoustic measurements were compared with two independent implementations of classical linear theory. Measured steady thrust and torque were used together with a free-wake analysis (to predict the thrust and drag distributions along the rotor radius) as input to this first-principles theoretical approach. Good agreement between theory and experiment was shown for both amplitude and phase for measurements made in those positions that minimized distortion of the radiated acoustic signature at low-frequencies.

  4. Model helicopter rotor high-speed impulsive noise: Measured acoustics and blade pressures

    NASA Technical Reports Server (NTRS)

    Boxwell, D. A.; Schmitz, F. H.; Splettstoesser, W. R.; Schultz, K. J.

    1983-01-01

    A 1/17-scale research model of the AH-1 series helicopter main rotor was tested. Model-rotor acoustic and simultaneous blade pressure data were recorded at high speeds where full-scale helicopter high-speed impulsive noise levels are known to be dominant. Model-rotor measurements of the peak acoustic pressure levels, waveform shapes, and directively patterns are directly compared with full-scale investigations, using an equivalent in-flight technique. Model acoustic data are shown to scale remarkably well in shape and in amplitude with full-scale results. Model rotor-blade pressures are presented for rotor operating conditions both with and without shock-like discontinuities in the radiated acoustic waveform. Acoustically, both model and full-scale measurements support current evidence that above certain high subsonic advancing-tip Mach numbers, local shock waves that exist on the rotor blades ""delocalize'' and radiate to the acoustic far-field.

  5. Research requirements to improve safety of civil helicopters

    NASA Technical Reports Server (NTRS)

    Waters, K. T.

    1977-01-01

    Helicopter and fixed-wing accident data were reviewed and major accident causal factors were established. The impact of accidents on insurance rates was examined and the differences in fixed-wing and helicopter accident costs discussed. The state of the art in civil helicopter safety was compared to military helicopters. Goals were established based on incorporation of known technology and achievable improvements that require development, as well as administrative-type changes such as the impact of improved operational planning, training, and human factors effects. Specific R and D recommendations are provided with an estimation of the payoffs, timing, and development costs.

  6. NASA helicopter blades get new paint job for safety

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Workers paint the blades of a NASA UH-1H helicopter, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  7. NASA helicopter blades get new paint job for safety

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Workers put the finishing touches on new paint for the blades of a NASA UH-1H helicopter. They have changed the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen from above by a second helicopter. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  8. Aluminum-lithium alloys in helicopters

    SciTech Connect

    Smith, A.F.

    1997-10-01

    Aluminium-lithium alloys are widely applied on the EH101 helicopter, designed and built jointly by GKN Westland Helicopters of England and Agusta S.p.A. of Italy. With the exception of the powder metallurgy alloy AA 5091, all the current commercially available aluminum-lithium alloys are produced by direct-chill casting, and require a precipitation-aging heat treatment to achieve the required properties. In aluminum-lithium alloys containing greater than 1.3% (by weight) of lithium, the intermetallic phase {delta}{prime}-Al{sub 3}Li precipitates upon natural or artificial aging, but the associated strengthening effect is insufficient to meet the medium or high strength levels usually required (the damage tolerant temper in AA 8090 is an exception).

  9. Pilot ejection, parachute, and helicopter crash injuries.

    PubMed

    McBratney, Colleen M; Rush, Stephen; Kharod, Chetan U

    2014-01-01

    USAF Pararescuemen (PJs) respond to downed aircrew as a fundamental mission for personnel recovery (PR), one of the Air Force's core functions. In addition to responding to these in Military settings, the PJs from the 212 Rescue Squadron routinely respond to small plane crashes in remote regions of Alaska. While there is a paucity of information on the latter, there have been articles detailing injuries sustained from helicopter crashes and while ejecting or parachuting from fixed wing aircraft. The following represents a new chapter added to the Pararescue Medical Operations Handbook, Sixth Edition (2014, editors Matt Wolf, MD, and Stephen Rush, MD, in press). It was designed to be a quick reference for PJs and their Special Operations flight surgeons to help with understanding of mechanism of injury with regard to pilot ejection, parachute, and helicopter accident injuries. It outlines the nature of the injuries sustained in such mishaps and provides an epidemiologic framework from which to approach the problem.

  10. NASA/FAA helicopter simulator workshop

    NASA Technical Reports Server (NTRS)

    Larsen, William E. (Editor); Randle, Robert J., Jr. (Editor); Bray, Richard S. (Editor); Zuk, John (Editor)

    1992-01-01

    A workshop was convened by the FAA and NASA for the purpose of providing a forum at which leading designers, manufacturers, and users of helicopter simulators could initiate and participate in a development process that would facilitate the formulation of qualification standards by the regulatory agency. Formal papers were presented, special topics were discussed in breakout sessions, and a draft FAA advisory circular defining specifications for helicopter simulators was presented and discussed. A working group of volunteers was formed to work with the National Simulator Program Office to develop a final version of the circular. The workshop attracted 90 individuals from a constituency of simulator manufacturers, training organizations, the military, civil regulators, research scientists, and five foreign countries.

  11. A cable detection lidar system for helicopters

    NASA Technical Reports Server (NTRS)

    Grossmann, Benoist; Capbern, Alain; Defour, Martin; Fertala, Remi

    1992-01-01

    Helicopters in low-level flight are endangered by power lines or telephone wires, especially when flying at night and under poor visibility conditions. In order to prevent 'wire strike', Thomson has developed a lidar system consisting of a pulsed diode laser emitting in the near infrared region (lambda = 0.9 microns). The HOWARD (Helicopter Obstacle Warning and Detection) System utilizes a high repetition rate diode laser (PRE = 20 KHz) along with counter-rotating prisms for laser beam deflection with a total field of view of 30 degrees. This system was successfully field tested in 1991. HOWARD can detect one inch wires at ranges up to 200 meters. We are presently in the process of developing a flyable compact lidar system capable of detection ranges in the order of 400 meters.

  12. Effect of helicopter noise on passenger annoyance

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Leatherwood, J. D.

    1979-01-01

    The effects of helicopter interior noise on passenger annoyance for both reverie and listening situations was investigated. The relative effectiveness of several metrics for quantifying annoyance response for these situations was also studied. The noise stimuli were based upon recordings of the interior noise of civil helicopter research aircraft. These noises were presented at levels ranging from approximately 70 to 86 d with various tonal components selectively attenuated to give a range of spectra. The listening task required the subjects to listen to and record phonetically-balanced words presented within the various noise environments. Results indicate that annoyance during a listening condition is generally higher than annoyance under a reverie condition for corresponding interior noise environments. Attenuation of the tonal components results in increases in listening performance but has only a small effect upon annoyance for a given noise level.

  13. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Rich, M. J.; Lowry, D. W.

    1982-01-01

    This first interim report presents the technical background for including environmental effects in the design of helicopter composite structures, and test results after approximately two year field exposure of components and panels. Composite structural components were removed from Sikorsky S-76 helicopters commercially operated in the Gulf Coast region of Louisiana. Fatigue tests were conducted for a graphite/epoxy tail rotor spar and static test for a graphite/epoxy and Kevlar/epoxy stabilizer. Graphite/epoxy and Kevlar/epoxy panels are being exposed to the outdoor environment in Stratford, Connecticut and West Palm Beach, Florida. For this reporting period the two year panels were returned, moisture measurements taken, and strength tests conducted. Results are compared with initial type certificate strengths for components and with initial laboratory coupon tests for the exposed panels. Comparisons are also presented with predicted and measured moisture contents.

  14. Flight service evaluation of composite helicopter components

    NASA Technical Reports Server (NTRS)

    Rich, M. J.; Lowry, D. W.

    1983-01-01

    This first interim report presents the technical background for including environmental effects in the design of helicopter composite structures, and test results after approximately two year field exposure of components and panels. Composite structural components were removed from Sikorsky S-76 helicopters commercially operated in the Gulf Coast region of Louisiana. Fatigue tests were conducted for a graphite/epoxy tail rotor spar and static test for a graphite/epoxy and Kevlar/epoxy stabilizer. Graphite/epoxy and Kevlar/epoxy panels are being exposed to the outdoor environment in Stratford, Connecticut and West Palm Beach, Florida. For this reporting period the two year panels were returned, moisture measurements taken, and strength tests conducted. Results are compared with initial type certificate strengths for components and with initial laboratory coupon tests for the exposed panels. Comparisons are also presented with predicted and measured moisture contents.

  15. Pilot ejection, parachute, and helicopter crash injuries.

    PubMed

    McBratney, Colleen M; Rush, Stephen; Kharod, Chetan U

    2014-01-01

    USAF Pararescuemen (PJs) respond to downed aircrew as a fundamental mission for personnel recovery (PR), one of the Air Force's core functions. In addition to responding to these in Military settings, the PJs from the 212 Rescue Squadron routinely respond to small plane crashes in remote regions of Alaska. While there is a paucity of information on the latter, there have been articles detailing injuries sustained from helicopter crashes and while ejecting or parachuting from fixed wing aircraft. The following represents a new chapter added to the Pararescue Medical Operations Handbook, Sixth Edition (2014, editors Matt Wolf, MD, and Stephen Rush, MD, in press). It was designed to be a quick reference for PJs and their Special Operations flight surgeons to help with understanding of mechanism of injury with regard to pilot ejection, parachute, and helicopter accident injuries. It outlines the nature of the injuries sustained in such mishaps and provides an epidemiologic framework from which to approach the problem. PMID:25399374

  16. Forward Flight of a Small Coaxial Helicopter

    NASA Astrophysics Data System (ADS)

    Sumino, Hiroki; Sunada, Shigeru; Tokutake, Hiroshi; Hatayama, Yuki

    The toy model coaxial helicopter for entertainment has a characteristic that it goes left when the operation for forward motion is made with the controller. The reason for this characteristic was made clear as follows: The phase difference between cyclic pitch and flapping motion is varied with the forward velocity. For this helicopter, the azimuth angles for the cyclic pitch inputs to the lower rotor are determined for a hovering flight. Then, the tip path plane of the lower rotor is inclined to the left and forward, when the operation for forward motion is kept. And the fuselage moves to the left and forward. On the other hand, during the forward motion, the inclination of the tip path plane of the upper rotor is varied by the stabilizer bar, whose motion is mainly determined by the fuselage attitude. Then, there are both moments when the upper rotor suppresses the fuselage motion generated by the lower rotor and when it promotes the fuselage motion.

  17. Structural dynamics, stability, and control of helicopters

    NASA Technical Reports Server (NTRS)

    Meirovitch, L.; Kraige, L. G.; Hale, A. L.

    1976-01-01

    The dynamic synthesis of a helicopter is reported. The method of approach is a variation of the component mode synthesis in the sense that it regards the aircraft as an assemblage of interconnected substructures. The equations of motion are derived in general form by means of the Lagrangian formulation in conjunction with an orderly kinematical procedure that takes into account the superposition of motion of various substructures, thus circumventing constraint problems.

  18. Autonomous vertical autorotation for unmanned helicopters

    NASA Astrophysics Data System (ADS)

    Dalamagkidis, Konstantinos

    Small Unmanned Aircraft Systems (UAS) are considered the stepping stone for the integration of civil unmanned vehicles in the National Airspace System (NAS) because of their low cost and risk. Such systems are aimed at a variety of applications including search and rescue, surveillance, communications, traffic monitoring and inspection of buildings, power lines and bridges. Amidst these systems, small helicopters play an important role because of their capability to hold a position, to maneuver in tight spaces and to take off and land from virtually anywhere. Nevertheless civil adoption of such systems is minimal, mostly because of regulatory problems that in turn are due to safety concerns. This dissertation examines the risk to safety imposed by UAS in general and small helicopters in particular, focusing on accidents resulting in a ground impact. To improve the performance of small helicopters in this area, the use of autonomous autorotation is proposed. This research goes beyond previous work in the area of autonomous autorotation by developing an on-line, model-based, real-time controller that is capable of handling constraints and different cost functions. The approach selected is based on a non-linear model-predictive controller, that is augmented by a neural network to improve the speed of the non-linear optimization. The immediate benefit of this controller is that a class of failures that would otherwise result in an uncontrolled crash and possible injuries or fatalities can now be accommodated. Furthermore besides simply landing the helicopter, the controller is also capable of minimizing the risk of serious injury to people in the area. This is accomplished by minimizing the kinetic energy during the last phase of the descent. The presented research is designed to benefit the entire UAS community as well as the public, by allowing for safer UAS operations, which in turn also allow faster and less expensive integration of UAS in the NAS.

  19. Fatigue life estimates for helicopter loading spectra

    NASA Technical Reports Server (NTRS)

    Khosrovaneh, A. K.; Dowling, N. E.; Berens, A. P.; Gallagher, J. P.

    1990-01-01

    Helicopter loading histories applied to notch metal samples are used as examples, and their fatigue lives are calculated by using a simplified version of the local strain approach. This simplified method has the advantage that it requires knowing the loading history in only the reduced form of ranges and means and number of cycles from the rain-flow cycle counting method. The calculated lives compare favorably with test data.

  20. Fatigue life estimates for helicopter loading spectra

    NASA Technical Reports Server (NTRS)

    Khosrovaneh, A. K.; Dowling, N. E.; Berens, A. P.; Gallagher, J. P.

    1989-01-01

    Helicopter loading histories applied to notch metal samples are used as examples, and their fatigue lives are calculated by using a simplified version of the local strain approach. This simplified method has the advantage that it requires knowing the loading history in only the reduced form of ranges and means and number of cycles from the rain-flow cycle counting method. The calculated lives compare favorably with test data.

  1. Analysis of helicopter blade vortex structure by laser velocimetry

    NASA Astrophysics Data System (ADS)

    Boutier, A.; Lefèvre, J.; Micheli, F.

    1996-05-01

    In descent flight, helicopter external noise is mainly generated by the Blade Vortex Interaction (BVI). To under-stand the dynamics of this phenomenon, the vortex must be characterized before its interaction with the blade, which means that its viscous core radius, its strength and its distance to the blade have to be determined by non-intrusive measurement techniques. As part of the HART program (Higher Harmonic Control Aeroacoustic Rotor Test, jointly conducted by US Army, NASA, DLR, DNW and ONERA), a series of tests have been made in the German Dutch Wind Tunnel (DNW) on a helicopter rotor with 2 m long blades, rotating at 1040 rpm; several flight configurations, with an advance ratio of 0.15 and a shaft angle of 5.3°, have been studied with different higher harmonic blade pitch angles superposed on the conventional one (corresponding to the baseline case). The flow on the retreating side has been analyzed with an especially designed 3D laser velocimeter, and, simultaneously, the blade tip attitude has been determined in order to get the blade-vortex miss distance, which is a crucial parameter in the noise reduction. A 3D laser velocimeter, in backscatter mode with a working distance of 5 m, was installed on a platform 9 m high, and flow seeding with submicron incense smoke was achieved in the settling chamber using a remotely controlled displacement device. Acquisition of instantaneous velocity vectors by an IFA 750 yielded mean velocity and turbulence maps across the vortex as well as the vortex position, intensity and viscous radius. The blade tip attitude (altitude, jitter, angle of incidence) was recorded by the TART method (Target Attitude in Real Time) which makes use of a CCD camera on which is formed the image of two retroreflecting targets attached to the blade tip and lighted by a flash lamp. In addition to the mean values of the aforementioned quantities, spectra of their fluctuations have been established up to 8 Hz.

  2. Helicopter flights with night-vision goggles: Human factors aspects

    NASA Technical Reports Server (NTRS)

    Brickner, Michael S.

    1989-01-01

    Night-vision goggles (NVGs) and, in particular, the advanced, helmet-mounted Aviators Night-Vision-Imaging System (ANVIS) allows helicopter pilots to perform low-level flight at night. It consists of light intensifier tubes which amplify low-intensity ambient illumination (star and moon light) and an optical system which together produce a bright image of the scene. However, these NVGs do not turn night into day, and, while they may often provide significant advantages over unaided night flight, they may also result in visual fatigue, high workload, and safety hazards. These problems reflect both system limitations and human-factors issues. A brief description of the technical characteristics of NVGs and of human night-vision capabilities is followed by a description and analysis of specific perceptual problems which occur with the use of NVGs in flight. Some of the issues addressed include: limitations imposed by a restricted field of view; problems related to binocular rivalry; the consequences of inappropriate focusing of the eye; the effects of ambient illumination levels and of various types of terrain on image quality; difficulties in distance and slope estimation; effects of dazzling; and visual fatigue and superimposed symbology. These issues are described and analyzed in terms of their possible consequences on helicopter pilot performance. The additional influence of individual differences among pilots is emphasized. Thermal imaging systems (forward looking infrared (FLIR)) are described briefly and compared to light intensifier systems (NVGs). Many of the phenomena which are described are not readily understood. More research is required to better understand the human-factors problems created by the use of NVGs and other night-vision aids, to enhance system design, and to improve training methods and simulation techniques.

  3. Man-machine interface requirements - advanced technology

    NASA Technical Reports Server (NTRS)

    Remington, R. W.; Wiener, E. L.

    1984-01-01

    Research issues and areas are identified where increased understanding of the human operator and the interaction between the operator and the avionics could lead to improvements in the performance of current and proposed helicopters. Both current and advanced helicopter systems and avionics are considered. Areas critical to man-machine interface requirements include: (1) artificial intelligence; (2) visual displays; (3) voice technology; (4) cockpit integration; and (5) pilot work loads and performance.

  4. Helicopter immobilization of elk in southcentral Washington

    SciTech Connect

    McCorquodale, S.M.; Eberhardt, L.E. ); Petron, S.E. )

    1988-01-01

    Free-ranging elk are commonly immobilized for research or management by rifle-fired darts shot from a helicopter. Compounds used for this purpose have included succinylcholine chloride (succinylcholine), etorphine hydrochloride (etorphine), and xylazine hydrochloride (xylazine). To assess the efficacy of various immobilizing drugs used in helicopter applications, we darted 38 elk from a helicopter on the Arid Lands Ecology Reserve, Washington from 1983 to 1987. We used either succinylcholine, etorphine hydrochloride, or xylazine hydrochloride a primary immobilants. Unsuccessful immobilizations were most common in elk darted with succinylcholine. Yohimbine was used to reverse xylazine immobilizations. The use of xylazine and yohimbine provides an efficient, cost-effective alternative to etorphine, diprenorphine immobilization and reversal in elk while increasing handler safety. Etorphine appeared to be the best immobilant when extended pain-producing procedures (such as surgical telemetry implantation) are planned because it induced the longest and deepest anesthesia. When the potential to lose contact with darted animals exist, we believe succinylcholine may be the preferred immobilant because of rapid, spontaneous recovery.

  5. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033).

  6. Automated Power Assessment for Helicopter Turboshaft Engines

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Litt, Jonathan S.

    2008-01-01

    An accurate indication of available power is required for helicopter mission planning purposes. Available power is currently estimated on U.S. Army Blackhawk helicopters by performing a Maximum Power Check (MPC), a manual procedure performed by maintenance pilots on a periodic basis. The MPC establishes Engine Torque Factor (ETF), an indication of available power. It is desirable to replace the current manual MPC procedure with an automated approach that will enable continuous real-time assessment of available power utilizing normal mission data. This report presents an automated power assessment approach which processes data currently collected within helicopter Health and Usage Monitoring System (HUMS) units. The overall approach consists of: 1) a steady-state data filter which identifies and extracts steady-state operating points within HUMS data sets; 2) engine performance curve trend monitoring and updating; and 3) automated ETF calculation. The algorithm is coded in MATLAB (The MathWorks, Inc.) and currently runs on a PC. Results from the application of this technique to HUMS mission data collected from UH-60L aircraft equipped with T700-GE-701C engines are presented and compared to manually calculated ETF values. Potential future enhancements are discussed.

  7. Analysis of muscle fatigue in helicopter pilots.

    PubMed

    Balasubramanian, Venkatesh; Dutt, Ashwani; Rai, Shobhit

    2011-11-01

    Helicopter pilots espouse ergonomically unfavourable postures and endure vibration which result in low back pain. The objective of this study was to investigate the effects of a helicopter flight on pilots back and shoulder muscles using surface Electromyography (sEMG) analysis. This study also correlates low back pain symptoms from Rehabilitation Bioengineering Group Pain Scale (RBGPS) questionnaire with muscle fatigue rates obtained. RBGPS was administered on 20 Coast Guard helicopter pilots. sEMG was acquired before and after flight from erector spinae and trapezius muscles in 8 of these 20 pilots. Statistical analysis of time and frequency domain parameters indicated significant fatigue in right trapezius muscle due to flying. Muscle fatigue correlated with average duration of flight (r² = 0.913), total service as pilot (r² = 0.825), pain (r² = 0.463) and total flying hours (r² = 0.507). However, muscle fatigue weakly correlated with Body Mass Index (BMI) (r² = 0.000144) and age (r² = 0.033). PMID:21411058

  8. High-integrity databases for helicopter operations

    NASA Astrophysics Data System (ADS)

    Pschierer, Christian; Schiefele, Jens; Lüthy, Juerg

    2009-05-01

    Helicopter Emergency Medical Service missions (HEMS) impose a high workload on pilots due to short preparation time, operations in low level flight, and landings in unknown areas. The research project PILAS, a cooperation between Eurocopter, Diehl Avionics, DLR, EADS, Euro Telematik, ESG, Jeppesen, the Universities of Darmstadt and Munich, and funded by the German government, approached this problem by researching a pilot assistance system which supports the pilots during all phases of flight. The databases required for the specified helicopter missions include different types of topological and cultural data for graphical display on the SVS system, AMDB data for operations at airports and helipads, and navigation data for IFR segments. The most critical databases for the PILAS system however are highly accurate terrain and obstacle data. While RTCA DO-276 specifies high accuracies and integrities only for the areas around airports, HEMS helicopters typically operate outside of these controlled areas and thus require highly reliable terrain and obstacle data for their designated response areas. This data has been generated by a LIDAR scan of the specified test region. Obstacles have been extracted into a vector format. This paper includes a short overview of the complete PILAS system and then focus on the generation of the required high quality databases.

  9. Damping augmentation of helicopter rotors using magnetorheological dampers

    NASA Astrophysics Data System (ADS)

    Zhao, Yongsheng

    This dissertation describes an investigation exploring the use of magnetorheological (MR) dampers to augment the stability of helicopter rotors. Helicopters with advanced soft in-plane rotors are susceptible to ground resonance instabilities due to the coupling of the lightly damped rotor lag modes and fuselage modes. Traditional passive lag dampers, such as hydraulic or elastomeric dampers, can be used to alleviate these instabilities. However, these passive dampers suffer from the disadvantages that they produce large damper loads in forward flight conditions. These damper forces increase fatigue loads and reduce component life. Thus, it is desirable to have lag dampers controllable or adaptable, so that the damper can apply loads only when needed. MR fluid based dampers have recently been considered for helicopter lag damping augmentation because the forces generated by these dampers can be controlled by an applied magnetic field. In this dissertation, control schemes to integrate MR dampers with helicopters are developed and the influences of the MR dampers on rotorcraft ground resonance are studied. Specifically, the MR dampers are incorporated into the ground resonance model in two ways: using a linear equivalent viscous damping and using a nonlinear damper model. The feasibility of using MR dampers to stabilize ground resonance is studied. The open loop on-off control is utilized where MR dampers are turned on over RPM where ground resonance occurs, and turned off otherwise. To further explore the damping control ability of MR dampers, the nonlinear semi-active closed loop feedback control strategies are developed: feedback linearization control and sliding mode control. The performance of the two control strategies is evaluated using two examples: to stabilize an unstable rotor and to augment the stability of a marginally stable rotor. In addition, the robustness of the closed loop control strategies is studied using two cases: damper degradation and

  10. Model Tests on the Economy and Effectiveness of Helicopter Propellers

    NASA Technical Reports Server (NTRS)

    Munk, Max M

    1925-01-01

    The average velocity of helicopter blades relative to the air is greater than that of airplane wings. The helicopter may turn out to be more economical than the airplane wing for extreme velocities of horizontal flight, the airplane then requiring a very great speed range.

  11. Summary of drive-train component technology in helicopters

    NASA Technical Reports Server (NTRS)

    Weden, G. J.; Coy, J. J.

    1984-01-01

    A review of current helicopters was conducted to determine the technology in the drive-train systems. The design features are highlighted including reliability characteristics in transmission systems for the OH-58, UH-1, CH-47, and UH-60 helicopters. In addition, trade-offs involving cost, reliability and life are discussed.

  12. 77 FR 20319 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-04

    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM...-365N, SA-365N1, SA-366G1, AS-365N2, AS 365 N3, EC 155B, and EC155B1 helicopters. This proposed AD...

  13. The Helicopter Parent (Part 2): International Arrivals and Departures

    ERIC Educational Resources Information Center

    Somers, Patricia; Settle, Jim

    2010-01-01

    The phenomenon of helicopter parenting has been widely reported, yet the research literature is anemic on the topic. Based on interviews and focus groups involving 190 academic and student services professionals, this article continues by discussing the social, psychological, economic, and cultural factors that influence helicoptering; exploring…

  14. 77 FR 43734 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-26

    ...'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect... Helicopters AGENCY: Federal Aviation Administration (FAA) DOT. ACTION: Notice of proposed rulemaking (NPRM... AS350BA helicopters with certain AERAZUR emergency flotation gear container assemblies installed....

  15. 77 FR 44118 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... Order 12866; 2. Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034... Helicopters AGENCY: Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Final... France (Eurocopter) Model EC155B1 helicopters with a certain automated flight control system...

  16. 29 CFR 1926.958 - External load helicopters.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false External load helicopters. 1926.958 Section 1926.958 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... External load helicopters. In all operations performed using a rotorcraft for moving or placing...

  17. Small helicopter could find niche in remote heavy lift operations

    SciTech Connect

    Not Available

    1994-02-21

    A new helicopter specifically designed for external vertical lift operations, such as moving transportable rig components or seismic equipment in remote locations, operates more efficiently than most other medium or heavy-lift helicopters, according to manufacturer Kaman Aerospace. The single-pilot helicopter was designed as an aerial truck for efficient lifting of heavy loads but with the operating costs of a light-lift craft. The K-Max helicopter can lift more pounds of cargo per gallon of fuel consumed than other similar helicopters, according to Kaman. For example, to transport a 5,000-lb load at an elevation of 8,000 ft, the K-Max helicopter consumes 85 gal of fuel/hr. Under the same load conditions, the next most efficient commercially available helicopter consumes 160 gal of fuel/hr and requires two pilots. The 4,500-lb helicopter can lift 5,000 lb to an altitude of 8,000 ft or about 6,000 lb at low altitudes.

  18. 29 CFR 1926.958 - External load helicopters.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false External load helicopters. 1926.958 Section 1926.958 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... External load helicopters. In all operations performed using a rotorcraft for moving or placing...

  19. 29 CFR 1926.958 - External load helicopters.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false External load helicopters. 1926.958 Section 1926.958 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... External load helicopters. In all operations performed using a rotorcraft for moving or placing...

  20. 78 FR 26712 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-08

    ... FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska to the extent that it... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM... EC 155B, EC155B1, SA-365N, SA- 365N1, AS-365N2, AS 365 N3, and SA-366G1 helicopters. This proposed...

  1. 29 CFR 1926.958 - External load helicopters.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false External load helicopters. 1926.958 Section 1926.958 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... External load helicopters. In all operations performed using a rotorcraft for moving or placing...

  2. 77 FR 63262 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-16

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM..., L, and L1 helicopters to require an initial and repetitive inspections of the outer skin, butt...

  3. The Helicopter Parent: Research toward a Typology (Part I)

    ERIC Educational Resources Information Center

    Somers, Patricia; Settle, Jim

    2010-01-01

    With 117,000 hits on a recent Google[TM] search, the phenomenon of helicopter parenting has been widely reported in the popular press. Yet the scholarly literature is anemic on the topic. This article, part one of a two-part series, presents the small body of research on helicopter parenting and describes a qualitative study of 190 participants…

  4. 78 FR 34288 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... 12866; 2. Is not a ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM... AS332L2 and EC225LP helicopters. This proposed AD would require inspecting the torque value of the...

  5. 29 CFR 1926.958 - External load helicopters.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false External load helicopters. 1926.958 Section 1926.958 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... External load helicopters. In all operations performed using a rotorcraft for moving or placing...

  6. 78 FR 44043 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-23

    ... ``significant rule'' under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM... EC225LP helicopters. This proposed AD ] would require inspecting the swashplates for corrosion or a...

  7. 78 FR 63429 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of proposed rulemaking (NPRM..., AS332L1, AS332L2, EC225LP, and SA330J helicopters with a certain tail rotor control turnbuckle...

  8. Modeling and Control of a Co-Axial Helicopter

    NASA Astrophysics Data System (ADS)

    Zare Seisan, Farid

    This thesis lays the foundations for the development of a small autonomous coaxial helicopter. This is an helicopter with two propellers mounted on the same axis and revolving in opposite directions. To steer the helicopter, this thesis proposes a mechanism that moves the helicopter's centre of mass. Although such a mechanism has already been investigated experimentally in the literature, it has never been rigorously modeled, and a theoretical analysis has never been performed. This thesis, for the first time, presents an accurate mathematical model of the coaxial helicopter which takes into account the gyroscopic effects of the rotors, the reaction forces and torques exerted by the moving mass actuator on the helicopter body, and the fact that the inertia of the helicopter is time-varying. A nonlinear controller is rigorously derived which makes the helicopter hover at desired positions in three-space. A number of physical prototypes are discussed. None of them is capable of autonomous flight yet, but the experimental and simulation results provide reassurances that the proposed methodology is viable.

  9. Astronaut James Lovell hoisted from water by recovery helicopter

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut James A. Lovell Jr., pilot of the Gemini 7 space flight, is hoisted from the water by a recovery helicopter from the Aircraft Carrier U.S.S. Wasp. Astronaut Frank Borman, command pilot, waits in the raft to be hoisted aboard the helicopter.

  10. 78 FR 58256 - Airworthiness Directives; Eurocopter France Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-23

    ... (78 FR 24041) for Eurocopter Model AS350B3 helicopters with MOD 07 5601 installed. AD 2012-25-04... requirements of AD 2012-25-04, Amendment 39-17285 (78 FR 24041, April 24, 2013). Additionally, this proposed AD... FR 24041, April 24, 2013). Modifying the helicopter would be terminating action for the...

  11. 77 FR 56528 - Airworthiness Directives; Various Restricted Category Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-13

    ... installed on the Bell Model 212 helicopters, we issued AD No. 2010-03-03, Amendment 39-16186 (75 FR 5681... installed on other Bell model helicopters. We then issued AD No. 2011-23-02 (76 FR 68301, November 4, 2011..., refinishing the sanded area; Applying a light coat of preservative oil to all surfaces of the M/R...

  12. 77 FR 57524 - Stage 3 Helicopter Noise Certification Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-18

    ... (44 FR 42410, July 9, 1979) that proposed first ever helicopter noise certification standards that... an NPRM (Notice No. 86-3, 51 FR 7878) that proposed helicopter certification standards that were more... Noise Certification Standards AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice...

  13. Basic Helicopter Handbook, Revised. AC 61-13A.

    ERIC Educational Resources Information Center

    Federal Aviation Administration (DOT), Washington, DC. Flight Standards Service.

    This technical manual was designed to assist applicants preparing for the private, commercial, and flight instructor pilot certificates with a helicopter rating. The chapters outline general aerodynamics, aerodynamics of flight, loads and load factors, function of controls, other helicopter components and their functions, introduction to the…

  14. 77 FR 30230 - Airworthiness Directives; Eurocopter Deutschland Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-22

    ... Deutschland GmbH Model MBB-BK117 C-2 helicopters with certain Generator Control Units (GCU) installed. This proposed AD is prompted by reports of internal short circuits in certain GCUs. The proposed actions are... loss of control of the helicopter. DATES: We must receive comments on this proposed AD by July 23,...

  15. Application of a Comprehensive Analytical Model of Rotor Aerodynamics and Dynamics (CAMRAD) to the McDonnell Douglas AH-64A helicopter

    NASA Technical Reports Server (NTRS)

    Callahan, Cynthia B.; Bassett, Duane E.

    1988-01-01

    A model of the AH-64A helicopter was generated in a Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics (CAMRAD) in an effort to validate its analytical capabilities for modeling a current advanced Army helicopter. The initial phase of the effort involved the generation of CAMRAD input files necessary for the complete aerodynamic, structural, and dynamic definition of the production AH-64A helicopter. The input files were checked by making comparisons of CAMRAD full helicopter trim and main rotor blade natural frequency predictions with those of full helicopter trim program, Blade Element Trim (BETRIM), and dynamic analysis code, Dynamic Analysis Research Tool (DART), respectively. The main thrust concerned the application of the AH-64A CAMRAD model thus developed and verified for main rotor blade structural loads predictions and comparison with DART analytical results. The investigation provided insight not only into the usefulness of CAMRAD for the AH-64A performance and dynamics prediction, but also into the limitations of the program for modeling advanced rotor and fuselage systems. The model development effort is discussed, the results of the CAMRAD correlation studies presented, and some general conclusions are offered on the applicability of CAMRAD for rotor aeroelastic loads prediction for current and future rotorcraft configurations.

  16. Investigation of the effects of bandwidth and time delay on helicopter roll-axis handling qualities

    NASA Technical Reports Server (NTRS)

    Pausder, Heinz-Juergen; Blanken, Chris L.

    1993-01-01

    Several years of cooperative research conducted under the U.S./German Memorandum of Understanding (MOU) in helicopter flight control has recently resulted in a successful handling qualities study. The focus of this cooperative research has been the effects on handling qualities due to time delays in combination with a high bandwidth vehicle. The jointly performed study included the use of U.S. ground-based simulation and German in-flight simulation facilities. The NASA-Ames Vertical Motion Simulator (VMS) was used to develop a high bandwidth slalom tracking task which took into consideration the constraints of the facilities. The VMS was also used to define a range of the test parameters and to perform initial handling qualities evaluations. The flight tests were conducted using DLR's variable-stability BO 105 S3 Advanced Technology Testing Helicopter System (ATTHeS). Configurations included a rate command and an attitude command response system with added time delays up to 160 milliseconds over the baseline and bandwidth values between 1.5 and 4.5 rad/sec. Sixty-six evaluations were performed in about 25 hours of flight time during ten days of testing. The results indicate a need to more tightly constrain the allowable roll axis phase delay for the Level 1 and Level 2 requirements in the U.S. Army's specification for helicopter handling qualities, ADS-33C.

  17. Helmet mounted display supporting helicopter missions during en route flight and landing

    NASA Astrophysics Data System (ADS)

    Lueken, Thomas; Doehler, Hans-Ullrich; Schmerwitz, Sven

    2016-05-01

    Degraded visual environment is still a major problem for helicopter pilots especially during approach and landing. Particularly with regard to the landing phase, pilot's eyes must be directed outward in order to find visual cues as indicators for drift estimation. If lateral speed exceeds the limits it can damage the airframe or in extreme cases lead to a rollover. Since poor visibility can contribute to a loss of situation awareness and spatial disorientation, it is crucial to intuitively provide the pilot with the essential visual information he needs for a safe landing. With continuous technology advancement helmet-mounted displays (HMD) will soon become a spreading technology, because look through capability is an enabler to offer monitoring the outside view while presenting flight phase depending symbologies on the helmet display. Besides presenting primary flight information, additional information for obstacle accentuation or terrain visualization can be displayed on the visor. Virtual conformal elements like 3D pathway depiction or a 3D landing zone representation can help the pilot to maintain control until touchdown even during poor visual conditions. This paper describes first investigations in terms of both en route and landing symbology presented on a helmet mounted display system in the scope of helicopter flight trials with DLR's flying helicopter simulator ACT/FHS.

  18. NASA/FAA flight-test investigation of helicopter microwave landing system approaches

    NASA Technical Reports Server (NTRS)

    Peach, I. L., Jr.; Bull, J. S.; Anderson, D. J.; Dugan, D. C.; Ross, V. L.; Hunting, A. W.; Pate, D. P.; Savage, J. C.

    1980-01-01

    The helicopter Microwave Landing System flight-test investigations, conducted by a joint NASA/FAA effort in order to gather statistical data for establishing terminal instrument procedures criteria, and to provide a performance data base for developing advanced MLS guidance concepts, are presented. The specific flight-test objectives were to: (1) develop acceptable angle-only MLS approach profiles; (2) determine tracking errors; (3) determine altitude loss during missed approach; (4) evaluate guidance display sensitivities; and (5) evaluate pilot acceptability. Fourteen pilots flew 140 manual (without stability augmentation) dual-pilot simulated instrument approaches in a UH-1H helicopter. The flight profiles flown included 3-, 6-, and 9-degree glideslope, centerline approaches to decision heights of 50, 100, and 150 ft, respectively. The angular guidance display sensitivities and the data acquisition system are also described. Eight major conclusions are made, and include the following: (1) the use of pitch attitude to control airspeed and collective to control glideslope was the preferred pilot technique for the steep glideslope approaches, and (2) angular guidance deviation indicator sensitivity requirements for helicopter MLS approaches to STOLports and heliports have been found to be significantly different from standard ILS sensitivities.

  19. Hover and forward flight acoustics and performance of a small-scale helicopter rotor system

    NASA Technical Reports Server (NTRS)

    Kitaplioglu, C.; Shinoda, P.

    1985-01-01

    A 2.1-m diam., 1/6-scale model helicopter main rotor was tested in hover in the test section of the NASA Ames 40- by 80- Foot Wind Tunnel. Subsequently, it was tested in forward flight in the Ames 7- by 10-Foot Wind Tunnel. The primary objective of the tests was to obtain performance and noise data on a small-scale rotor at various thrust coefficients, tip Mach numbers, and, in the later case, various advance ratios, for comparisons with similar existing data on full-scale helicopter rotors. This comparison yielded a preliminary evaluation of the scaling of helicopter rotor performance and acoustic radiation in hover and in forward flight. Correlation between model-scale and full-scale performance and acoustics was quite good in hover. In forward flight, however, there were significant differences in both performance and acoustic characteristics. A secondary objective was to contribute to a data base that will permit the estimation of facility effects on acoustic testing.

  20. Investigation of the effects of bandwidth and time delay on helicopter roll-axis handling qualities

    NASA Technical Reports Server (NTRS)

    Blanken, Chris L.; Pausder, Heinz-Jurgen

    1994-01-01

    Several years of cooperative research conducted under the U.S./German Memorandum of Understanding (MOU) in helicopter aeromechanics have recently resulted in a successful handling qualities study. The focus of this cooperative research has been the effect of time delays in a high bandwidth vehicle on handling qualities. The jointly performed study included the use of U.S. ground-based simulation and German in-flight simulation facilities. The NASA-Ames Vertical Motion Simulator (VMS) was used to develop a high bandwidth slalom tracking task which took into consideration the constraints of the facilities. The VMS was used to define a range of the test parameters and to perform initial handling qualities evaluations. The flight tests were conducted using DLR's variable-stability BO 105 S3 Advanced Technology Testing Helicopter System (ATTHeS). Configurations included a rate command and an attitude command response system with added time delays of up to 160 milliseconds over the baseline and band width values between 1.5 and 4.5 rad/sec. Sixty-six evaluations were performed in about 25 hours of flight time during ten days of testing. The results indicate a need to more tightly constrain the allowable roll axis phase delay for the Level 1 and Level 2 requirements in the U.S. Army's specification for helicopter handling qualities Aeronautical Design Standard (ADS)-33C.

  1. Flight investigation of helicopter IFR approaches to oil rigs using airborne weather and mapping radar

    NASA Technical Reports Server (NTRS)

    Bull, J. S.; Hegarty, D. M.; Phillips, J. D.; Sturgeon, W. R.; Hunting, A. W.; Pate, D. P.

    1979-01-01

    Airborne weather and mapping radar is a near-term, economical method of providing 'self-contained' navigation information for approaches to offshore oil rigs and its use has been rapidly expanding in recent years. A joint NASA/FAA flight test investigation of helicopter IFR approaches to offshore oil rigs in the Gulf of Mexico was initiated in June 1978 and conducted under contract to Air Logistics. Approximately 120 approaches were flown in a Bell 212 helicopter by 15 operational pilots during the months of August and September 1978. The purpose of the tests was to collect data to (1) support development of advanced radar flight director concepts by NASA and (2) aid the establishment of Terminal Instrument Procedures (TERPS) criteria by the FAA. The flight test objectives were to develop airborne radar approach procedures, measure tracking errors, determine accpetable weather minimums, and determine pilot acceptability. Data obtained will contribute significantly to improved helicopter airborne radar approach capability and to the support of exploration, development, and utilization of the Nation's offshore oil supplies.

  2. 76 FR 10489 - Special Conditions: Bell Helicopter Textron Canada Limited Model 407 Helicopter, Installation of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-25

    ... System (AP/SAS) AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final special conditions.../Stabilization Augmentation System (AP/SAS) that has potential failure conditions with more severe adverse... type certification (STC) to install an AP/SAS on a Bell model 407 helicopter. The Bell model...

  3. 78 FR 4759 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ..., 2011, at 76 FR 67628, the Federal Register published our notice of proposed rulemaking (NPRM), which... helicopters: AD 79-20-05, Amendments 39- 3572 (44 FR 55556, September 27, 1979), 39-3626 (44 FR 70123, December 6, 1979), and 39-3662 (45 FR 6922, January 31, 1980); AD 81-19-01, Amendment 39-4207 (46 FR...

  4. 78 FR 63858 - Airworthiness Directives; Bell Helicopter Textron, Inc. (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-25

    ... Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA-2013-0500; Directorate Identifier 2012-SW... Textron, Inc. (Bell) Helicopters AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule...) 280-6466; or at http://www.bellcustomer.com/files/ . You may review a copy of the referenced...

  5. 77 FR 36389 - Airworthiness Directives; Bell Helicopter Textron Canada, Limited, Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    ...@faa.gov . SUPPLEMENTARY INFORMATION: Discussion On February 3, 2012, at 77 FR 5423, the Federal... ``significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); (3) Will not...-17091; AD 2012-12-11] RIN 2120-AA64 Airworthiness Directives; Bell Helicopter Textron Canada,...

  6. 75 FR 12441 - Airworthiness Directives; MD Helicopters, Inc. Model MD-900 Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-16

    ... FR 42824, August 6, 1999), Docket No. 98-SW-42-AD, for the MDHI Model MD-900 helicopters was published in the Federal Register on October 22, 2009 (74 FR 54495). The action proposed to decrease the... Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and 3. Will not have a...

  7. 78 FR 66252 - Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-05

    ... . SUPPLEMENTARY INFORMATION: Discussion On June 7, 2013, at 78 FR 34280, the Federal Register published our notice... Model 206L helicopters (ASB 206L- 07-146). Comments After our NPRM (78 FR 34280, June 7, 2013) was... Executive Order 12866; (2) Is not a ``significant rule'' under DOT Regulatory Policies and Procedures (44...

  8. 78 FR 4762 - Airworthiness Directives; Bell Helicopter Textron Canada Limited (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-23

    ... Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska to the extent... Model 206L, 206L-1, 206L-3, and 206L-4 helicopters. This AD requires inspecting certain hydraulic servo..., with a hydraulic servo actuator assembly (servo), part number (P/N) 206-076-062-103,...

  9. 77 FR 31172 - Airworthiness Directives; Bell Helicopter Textron Canada Limited Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-25

    ... sharon.y.miles@faa.gov . SUPPLEMENTARY INFORMATION: Discussion On February 3, 2012, at 77 FR 5425, the... Policies and Procedures (44 FR 11034, February 26, 1979); (3) Will not affect intrastate aviation in Alaska... (BHTC) Model 427 helicopters which requires replacing certain tailboom attachment hardware and...

  10. 76 FR 66609 - Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Model 407 and 427 Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ... specified by this AD are intended to prevent a malfunction of a servo in the flight control system and..., could result in a malfunction of a servo in the flight control system and subsequent loss of control of... servo in the flight control system and subsequent loss of control of the helicopter. The AD...

  11. 77 FR 64439 - Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Model Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-22

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... this proposed AD, contact Bell Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel... Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4, telephone (450) 437-2862 or (800) 363-8023,...

  12. 75 FR 62639 - Air Ambulance and Commercial Helicopter Operations, Part 91 Helicopter Operations, and Part 135...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-12

    ... in the Federal Register published on April 11, 2000 (65 FR 19477-78) or you may visit http://Dockets...). alternate airport weather minimums. Require helicopter pilots to demonstrate competency in recovery from... and to demonstrate their competency during initial and recurrent 14 CFR 135.293 evaluation check...

  13. 78 FR 65178 - Airworthiness Directives; Bell Helicopter Textron Canada (Bell) Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... manufacture of certain freewheel aft bearing caps without a lubrication channel to allow oil flow into the aft... subsequent loss of control of the helicopter. DATES: This AD is effective December 5, 2013. The Director of... . SUPPLEMENTARY INFORMATION: Discussion On June 20, 2013, at 78 FR 37158, the Federal Register published...

  14. Signal Detection Theory Applied to Helicopter Transmission Diagnostic Thresholds

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Keller, Jonathan A.; Wade, Daniel R.

    2009-01-01

    Helicopter Health Usage Monitoring Systems (HUMS) have potential for providing data to support increasing the service life of a dynamic mechanical component in the transmission of a helicopter. Data collected can demonstrate the HUMS condition indicator responds to a specific component fault with appropriate alert limits and minimal false alarms. Defining thresholds for specific faults requires a tradeoff between the sensitivity of the condition indicator (CI) limit to indicate damage and the number of false alarms. A method using Receiver Operating Characteristic (ROC) curves to assess CI performance was demonstrated using CI data collected from accelerometers installed on several UH60 Black Hawk and AH64 Apache helicopters and an AH64 helicopter component test stand. Results of the analysis indicate ROC curves can be used to reliably assess the performance of commercial HUMS condition indicators to detect damaged gears and bearings in a helicopter transmission.

  15. Signal Detection Theory Applied to Helicopter Transmission Diagnostic Thresholds

    NASA Technical Reports Server (NTRS)

    Dempsey, Paula J.; Keller, Jonathan A.; Wade, Daniel R.

    2008-01-01

    Helicopter Health Usage Monitoring Systems (HUMS) have potential for providing data to support increasing the service life of a dynamic mechanical component in the transmission of a helicopter. Data collected can demonstrate the HUMS condition indicator responds to a specific component fault with appropriate alert limits and minimal false alarms. Defining thresholds for specific faults requires a tradeoff between the sensitivity of the condition indicator (CI) limit to indicate damage and the number of false alarms. A method using Receiver Operating Characteristic (ROC) curves to assess CI performance was demonstrated using CI data collected from accelerometers installed on several UH60 Black Hawk and AH64 Apache helicopters and an AH64 helicopter component test stand. Results of the analysis indicate ROC curves can be used to reliably assess the performance of commercial HUMS condition indicators to detect damaged gears and bearings in a helicopter transmission.

  16. NASA helicopter blades get new paint job for safety

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Workers get ready to move a NASA UH-1H helicopter outside. They have been painting the blades of four NASA UH-1H helicopters, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  17. NASA helicopter blades get new paint job for safety

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A NASA UH-1H helicopter is prepared for transfer back to Patrick Air Force Base after being painted. The blades of four NASA UH-1H helicopters were repainted, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  18. NASA helicopter blades get new paint job for safety

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A newly repainted NASA helicopter is transported to S.R. 3 for return to Patrick AFB. Workers painted the blades of four NASA UH-1H helicopters, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  19. A NASA helicopter arrives at KSC for painting

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A NASA helicopter lands on S.R. 3 for transfer to Patrick Air Force Base. It is one of four UH-1H helicopters that will have its blades painted, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  20. A NASA helicopter arrives at KSC for painting

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A NASA helicopter from Patrick Air Force Base is about to land on S.R. 3. It is one of four UH-1H helicopters that will have its blades painted, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  1. A NASA helicopter arrives at KSC for painting

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A NASA helicopter is secured for transfer to Ransom Road at KSC. It is one of four UH-1H helicopters that will have its blades painted, changing the black to a pattern of white and yellow stripes. The pattern provides better visibility in smoke and fire conditions. When the rotors are turning, the stripes create a yellow and white circle that is more easily seen by a second helicopter from above. The helicopters, primarily used for security and medical evacuation for NASA, will be used to deliver water via buckets during brush fires. The change was made to comply with U.S. Fish and Wildlife and Department of Forestry regulations for helicopter-assisted fire control.

  2. Gulf of Mexico Helicopter Offshore System Technologies Engineering Needs Assessment

    NASA Technical Reports Server (NTRS)

    Koenke, Edmund J.; Carpenter, Elisabeth J.; Williams, Larry; Caiafa, Caesar

    1999-01-01

    The National Aeronautics and Space Administration (NASA), in partnership with the Federal Aviation Administration (FAA), is conducting a research and development program to modernize the National Airspace System (NAS). The mission of NASA's Advanced Air Transportation Technologies (AATT) project is to develop advanced Air Traffic Management (ATM) concepts and decision support tools for eventual deployment and implementation by the FAA and the private sector. One major objective of the NASA AATT project is to understand and promote the needs of all user classes. The Gulf of Mexico (GoMex) airspace has unique needs. A large number of helicopters operate in this area with only limited surveillance and sometimes-severe environmental conditions. Thunderstorms are the most frequent weather hazard during the spring, summer, and fall. In winter, reduced hours of daylight, low ceilings, strong winds, and icing conditions may restrict operations. Hurricanes impose the most severe weather hazard. The hurricane season, from June through October, normally requires at least one mass evacuation of all offshore platforms.

  3. 33 CFR 149.655 - What are the requirements for helicopter fueling facilities?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... EQUIPMENT Design and Equipment Helicopter Fueling Facilities § 149.655 What are the requirements for helicopter fueling facilities? Helicopter fueling facilities must comply with 46 CFR 108.489 or an equivalent... helicopter fueling facilities? 149.655 Section 149.655 Navigation and Navigable Waters COAST...

  4. 33 CFR 149.655 - What are the requirements for helicopter fueling facilities?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... EQUIPMENT Design and Equipment Helicopter Fueling Facilities § 149.655 What are the requirements for helicopter fueling facilities? Helicopter fueling facilities must comply with 46 CFR 108.489 or an equivalent... helicopter fueling facilities? 149.655 Section 149.655 Navigation and Navigable Waters COAST...

  5. 14 CFR 29.71 - Helicopter angle of glide: Category B.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...

  6. 14 CFR 29.71 - Helicopter angle of glide: Category B.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...

  7. 33 CFR 149.655 - What are the requirements for helicopter fueling facilities?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... EQUIPMENT Design and Equipment Helicopter Fueling Facilities § 149.655 What are the requirements for helicopter fueling facilities? Helicopter fueling facilities must comply with 46 CFR 108.489 or an equivalent... helicopter fueling facilities? 149.655 Section 149.655 Navigation and Navigable Waters COAST...

  8. 33 CFR 149.655 - What are the requirements for helicopter fueling facilities?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... EQUIPMENT Design and Equipment Helicopter Fueling Facilities § 149.655 What are the requirements for helicopter fueling facilities? Helicopter fueling facilities must comply with 46 CFR 108.489 or an equivalent... helicopter fueling facilities? 149.655 Section 149.655 Navigation and Navigable Waters COAST...

  9. 14 CFR 29.71 - Helicopter angle of glide: Category B.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...

  10. 33 CFR 149.655 - What are the requirements for helicopter fueling facilities?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... EQUIPMENT Design and Equipment Helicopter Fueling Facilities § 149.655 What are the requirements for helicopter fueling facilities? Helicopter fueling facilities must comply with 46 CFR 108.489 or an equivalent... helicopter fueling facilities? 149.655 Section 149.655 Navigation and Navigable Waters COAST...

  11. 14 CFR 29.71 - Helicopter angle of glide: Category B.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...

  12. 14 CFR 29.71 - Helicopter angle of glide: Category B.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Helicopter angle of glide: Category B. 29... AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Flight Performance § 29.71 Helicopter angle of glide: Category B. For each category B helicopter, except multiengine helicopters meeting...

  13. Step to improve neural cryptography against flipping attacks.

    PubMed

    Zhou, Jiantao; Xu, Qinzhen; Pei, Wenjiang; He, Zhenya; Szu, Harold

    2004-12-01

    Synchronization of neural networks by mutual learning has been demonstrated to be possible for constructing key exchange protocol over public channel. However, the neural cryptography schemes presented so far are not the securest under regular flipping attack (RFA) and are completely insecure under majority flipping attack (MFA). We propose a scheme by splitting the mutual information and the training process to improve the security of neural cryptosystem against flipping attacks. Both analytical and simulation results show that the success probability of RFA on the proposed scheme can be decreased to the level of brute force attack (BFA) and the success probability of MFA still decays exponentially with the weights' level L. The synchronization time of the parties also remains polynomial with L. Moreover, we analyze the security under an advanced flipping attack.

  14. Development of Novel Methods for the Reduction of Noise and Weight in Helicopter Transmissions

    NASA Technical Reports Server (NTRS)

    Dimofte, Florin; Keith, Theo G., Jr.

    2003-01-01

    Over the 70-year evolution of the helicopter, man's understanding of vibration control has greatly increased. However, in spite of the increased performance, the extent of helicopter vibration problems has not significantly diminished. Crew vibration and noise remains important factors in the design of all current helicopters. With more complex and critical demands being placed on aircrews, it is essential that vibration and noise not impair their performance. A major source of helicopter cabin noise (which has been measured at a sound pressure level of over 100 dB) is the gearbox. Reduction of this noise has been a goal of NASA and the U.S. Army. Gear mesh noise is typically in the frequency range of 1000 to 3000 Hz, a range important for speech. A requirement for U.S. Army/NASA Advanced Rotorcraft Transmission project has been a 10-dB reduction compared to current designs. A combined analytical/experimental effort has been underway, since the end of the 80's, to study effects of design parameters on noise production. The noise generated by the gear mesh can be transmitted to the surrounding media through the bearings that support the gear shaft. Therefore, the use of fluid film bearings instead of rolling element bearings could reduce the transmission noise by 10 dB. In addition, the fluid film bearings that support the gear shaft can change the dynamics of the gear assembly by providing damping to the system and by being softer than rolling element bearings. Wave bearings can attenuate, and filter, the noise generated by a machine component due to the dynamic stiffness and damping coefficients. The attenuation ratio could be as large as 35-40 dB. The noise components at higher frequencies than a synchronous frequency can be almost eliminated.

  15. Flight Test Identification and Simulation of a UH-60A Helicopter and Slung Load

    NASA Technical Reports Server (NTRS)

    Cicolani, Luigi S.; Sahai, Ranjana; Tucker, George E.; McCoy, Allen H.; Tyson, Peter H.; Tischler, Mark B.; Rosen, Aviv

    2001-01-01

    Helicopter slung-load operations are common in both military and civil contexts. Helicopters and loads are often qualified for these operations by means of flight tests, which can be expensive and time consuming. There is significant potential to reduce such costs both through revisions in flight-test methods and by using validated simulation models. To these ends, flight tests were conducted at Moffett Field to demonstrate the identification of key dynamic parameters during flight tests (aircraft stability margins and handling-qualities parameters, and load pendulum stability), and to accumulate a data base for simulation development and validation. The test aircraft was a UH-60A Black Hawk, and the primary test load was an instrumented 8- by 6- by 6-ft cargo container. Tests were focused on the lateral and longitudinal axes, which are the axes most affected by the load pendulum modes in the frequency range of interest for handling qualities; tests were conducted at airspeeds from hover to 80 knots. Using telemetered data, the dynamic parameters were evaluated in near real time after each test airspeed and before clearing the aircraft to the next test point. These computations were completed in under 1 min. A simulation model was implemented by integrating an advanced model of the UH-60A aerodynamics, dynamic equations for the two-body slung-load system, and load static aerodynamics obtained from wind-tunnel measurements. Comparisons with flight data for the helicopter alone and with a slung load showed good overall agreement for all parameters and test points; however, unmodeled secondary dynamic losses around 2 Hz were found in the helicopter model and they resulted in conservative stability margin estimates.

  16. Improving Attack Graph Visualization through Data Reduction and Attack Grouping

    SciTech Connect

    John Homer; Ashok Varikuti; Xinming Ou; Miles A. McQueen

    2008-09-01

    Various tools exist to analyze enterprise network systems and to produce attack graphs detailing how attackers might penetrate into the system. These attack graphs, however, are often complex and difficult to comprehend fully, and a human user may find it problematic to reach appropriate configuration decisions. This paper presents methodologies that can 1) automatically identify portions of an attack graph that do not help a user to understand the core security problems and so can be trimmed, and 2) automatically group similar attack steps as virtual nodes in a model of the network topology, to immediately increase the understandability of the data. We believe both methods are important steps toward improving visualization of attack graphs to make them more useful in configuration management for large enterprise networks. We implemented our methods using one of the existing attack-graph toolkits. Initial experimentation shows that the proposed approaches can 1) significantly reduce the complexity of attack graphs by trimming a large portion of the graph that is not needed for a user to understand the security problem, and 2) significantly increase the accessibility and understandability of the data presented in the attack graph by clearly showing, within a generated visualization of the network topology, the number and type of potential attacks to which each host is exposed.

  17. Flight testing of a binocular bisensor HMD for helicopter: some human factors aspects

    NASA Astrophysics Data System (ADS)

    Leger, Alain; Roumes, Corinne; Bergeaud, J. M.; Dareoux, P.; Gardelle, C.

    1998-08-01

    The need for night vision system in military helicopter has been recognized for many years now. Besides fixed FLIR and night vision goggles, helmet-mounted systems coupled with head-slaved IR sensor have been introduced during the last decade in modern attack helicopters. Monocular HMDs have been fielded on the AH-64 and used in operation. Human factors aspects pertaining to such night vision devices has been extensively reviewed and published. Though, full scale flight tests of binocular HMDs with integrated I2 and head coupled IR sensors have rarely been reported. A binocular helmet, with a 40 degree full overlap FOV has been developed under a contract of the French DGA. Two image intensifiers tubes located on each side of the head are integrated on the helmet, which also has full raster and stroke capacity. Both images are projected on the visor of the helmet and collimated to infinity. IR sensor imagery and navigation system are coupled to the helmet using an electro-magnetic head-tracker. Test flight of the helmet have been conducted by the French Flight Test Center on specially equipped Puma test-bed aircraft. Approximately 150 flight hours have been devoted to testing of the helmet, either with I2 and IR sensors.

  18. Analysis of potential helicopter vibration reduction concepts

    NASA Technical Reports Server (NTRS)

    Landgrebe, A. J.; Davis, M. W.

    1985-01-01

    Results of analytical investigations to develop, understand, and evaluate potential helicopter vibration reduction concepts are presented in the following areas: identification of the fundamental sources of vibratory loads, blade design for low vibration, application of design optimization techniques, active higher harmonic control, blade appended aeromechanical devices, and the prediction of vibratory airloads. Primary sources of vibration are identified for a selected four-bladed articulated rotor operating in high speed level flight. The application of analytical design procedures and optimization techniques are shown to have the potential for establishing reduced vibration blade designs through variations in blade mass and stiffness distributions, and chordwise center-of-gravity location.

  19. Helicopter in-flight stores jettison

    NASA Technical Reports Server (NTRS)

    Bement, Laurence J.; Jahsman, Dirck; Schimmel, Morry L.

    1990-01-01

    A helicopter emergency external-stores jettison system accommodating an experimental simplified mounting system is presented. The system's conceptual approach is described, including store interface, attachment, functional mechanisms, and system initiation. It is novel both in the stores' mounting interface logic and in the modifications to existing technology for the components. Two nonfragmenting 'ridge cut' explosive bolts were mounted in each 600-pound store to interface with a simple plate on the aircraft. Starting designs with proven technology and functional margins were demonstrated by analysis and test through the design and development. Design details of the system's components, from the explosive bolt to the initiation handle, are described.

  20. Composite curved frames for helicopter fuselage structure

    NASA Technical Reports Server (NTRS)

    Rich, M. J.; Lowry, D. W.

    1984-01-01

    This paper presents the results of analysis and testing of composite curved frames. A major frame was selected from the UH-60 Black Hawk helicopter and designed as a composite structure. The curved beam effects were expected to increase flange axial stresses and induce transverse bending. A NASTRAN finite element analysis was conducted and the results were used in the design of composite curved frame specimens. Three specimens were fabricated and five static tests were conducted. The NASTRAN analysis and test results are compared for axial, transverse, and Web strains. Results show the curved beam effects are closely predicted by a NASTRAN analysis and the effects increase with loading on the composite frames.

  1. Design of helicopter rotors to noise constraints

    NASA Technical Reports Server (NTRS)

    Schaeffer, E. G.; Sternfeld, H., Jr.

    1978-01-01

    Results of the initial phase of a research project to study the design constraints on helicopter noise are presented. These include the calculation of nonimpulsive rotor harmonic and broadband hover noise spectra, over a wide range of rotor design variables and the sensitivity of perceived noise level (PNL) to changes in rotor design parameters. The prediction methodology used correlated well with measured whirl tower data. Application of the predictions to variations in rotor design showed tip speed and thrust as having the most effect on changing PNL.

  2. Aerodynamic interactions between a 1/6-scale helicopter rotor and a body of revolution

    NASA Technical Reports Server (NTRS)

    Betzina, M. D.; Shinoda, P.

    1982-01-01

    A wind-tunnel investigation was conducted in which independent, steady-state aerodynamic forces and moments were measured on a 2.24-m-diam, two-bladed helicopter rotor and a body of revolution. The objective was to determine the interaction of the body on the rotor performance and the effect of the rotor on the body aerodynamics for variations in velocity, thrust, tip-path-plane angle of attack, rotor/body position, and body nose geometry. Results show that a body of revolution near the rotor can produce significant favorable or unfavorable effects on rotor performance, depending on the operating condition. Body longitudinal aerodynamic characteristics are significantly modified by the presence of an operating rotor and hub.

  3. Performance and loads data from a wind tunnel test of a full-scale, coaxial, hingeless rotor helicopter

    NASA Technical Reports Server (NTRS)

    Felker, F. F., III

    1981-01-01

    A full-scale XH-59A advancing blade concept helicopter was tested in Ames Research Center's 40 by 80 foot wind tunnel. The helicopter was tested with the rotor on and off, rotor hub fairings on and off, interrotor shaft fairing on and off, rotor instrumentation module on and off, and auxiliary propulsion thrust on and off. An advance ratio range of 0.25 and 0.45 with the rotor on and from 60 to 180 knots with the rotor off was investigated. Data on aerodynamic forces and moments, rotor loads, rotor control positions and vibration for the XH-59A as well as the aerodynamic performance of the isolated rotor are presented.

  4. General equilibrium characteristics of a dual-lift helicopter system

    NASA Technical Reports Server (NTRS)

    Cicolani, L. S.; Kanning, G.

    1986-01-01

    The equilibrium characteristics of a dual-lift helicopter system are examined. The system consists of the cargo attached by cables to the endpoints of a spreader bar which is suspended by cables below two helicopters. Results are given for the orientation angles of the suspension system and its internal forces, and for the helicopter thrust vector requirements under general circumstances, including nonidentical helicopters, any accelerating or static equilibrium reference flight condition, any system heading relative to the flight direction, and any distribution of the load to the two helicopters. Optimum tether angles which minimize the sum of the required thrust magnitudes are also determined. The analysis does not consider the attitude degrees of freedom of the load and helicopters in detail, but assumes that these bodies are stable, and that their aerodynamic forces in equilibrium flight can be determined independently as functions of the reference trajectory. The ranges of these forces for sample helicopters and loads are examined and their effects on the equilibrium characteristics are given parametrically in the results.

  5. Advances in traction drive technology

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Anderson, N. E.; Rohn, D. A.

    1983-01-01

    Traction drives are traced from early uses as main transmissions in automobiles at the turn of the century to modern, high-powered traction drives capable of transmitting hundreds of horsepower. Recent advances in technology are described which enable today's traction drive to be a serious candidate for off-highway vehicles and helicopter applications. Improvements in materials, traction fluids, design techniques, power loss and life prediction methods will be highlighted. Performance characteristics of the Nasvytis fixed-ratio drive are given. Promising future drive applications, such as helicopter main transmissions and servo-control positioning mechanisms are also addressed.

  6. Compound cycle engine for helicopter application

    NASA Technical Reports Server (NTRS)

    Castor, Jere G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded, ultra-high power density, light-weight diesel engine. The turbomachinery is similar to a moderate pressure ratio, free power turbine engine and the diesel core is high speed and a low compression ratio. This engine is considered a potential candidate for future military light helicopter applications. This executive summary presents cycle thermodynamic (SFC) and engine weight analyses performed to establish general engine operating parameters and configuration. An extensive performance and weight analysis based on a typical two hour helicopter (+30 minute reserve) mission determined final conceptual engine design. With this mission, CCE performance was compared to that of a T-800 class gas turbine engine. The CCE had a 31% lower-fuel consumption and resulted in a 16% reduction in engine plus fuel and fuel tank weight. Design SFC of the CCE is 0.33 lb-HP-HR and installed wet weight is 0.43 lbs/HP. The major technology development areas required for the CCE are identified and briefly discussed.

  7. Compound cycle engine for helicopter application

    NASA Technical Reports Server (NTRS)

    Castor, Jere; Martin, John; Bradley, Curtiss

    1987-01-01

    The compound cycle engine (CCE) is a highly turbocharged, power-compounded, ultra-high-power-density, lightweight diesel engine. The turbomachinery is similar to a moderate-pressure-ratio, free-power-turbine gas turbine engine and the diesel core is high speed and a low compression ratio. This engine is considered a potential candidate for future military helicopter applications. Cycle thermodynamic specific fuel consumption (SFC) and engine weight analyses performed to establish general engine operating parameters and configurations are presented. An extensive performance and weight analysis based on a typical 2-hour helicopter (+30 minute reserve) mission determined final conceptual engine design. With this mission, CCE performance was compared to that of a contemporary gas turbine engine. The CCE had a 31 percent lower-fuel consumption and resulted in a 16 percent reduction in engine plus fuel and fuel tank weight. Design SFC of the CCE is 0.33 lb/hp-hr and installed wet weight is 0.43 lb/hp. The major technology development areas required for the CCE are identified and briefly discussed.

  8. Helicopter magnetic survey conducted to locate wells

    SciTech Connect

    Veloski, G.A.; Hammack, R.W.; Stamp, V.; Hall, R.; Colina, K.

    2008-07-01

    A helicopter magnetic survey was conducted in August 2007 over 15.6 sq mi at the Naval Petroleum Reserve No. 3’s (NPR-3) Teapot Dome Field near Casper, Wyoming. The survey’s purpose was to accurately locate wells drilled there during more than 90 years of continuous oilfield operation. The survey was conducted at low altitude and with closely spaced flight lines to improve the detection of wells with weak magnetic response and to increase the resolution of closely spaced wells. The survey was in preparation for a planned CO2 flood for EOR, which requires a complete well inventory with accurate locations for all existing wells. The magnetic survey was intended to locate wells missing from the well database and to provide accurate locations for all wells. The ability of the helicopter magnetic survey to accurately locate wells was accomplished by comparing airborne well picks with well locations from an intense ground search of a small test area.

  9. An unsteady helicopter rotor: Fuselage interaction analysis

    NASA Technical Reports Server (NTRS)

    Lorber, Peter F.; Egolf, T. Alan

    1988-01-01

    A computational method was developed to treat unsteady aerodynamic interactions between a helicopter rotor, wake, and fuselage and between the main and tail rotors. An existing lifting line prescribed wake rotor analysis and a source panel fuselage analysis were coupled and modified to predict unsteady fuselage surface pressures and airloads. A prescribed displacement technique is used to position the rotor wake about the fuselage. Either a rigid blade or an aeroelastic blade analysis may be used to establish rotor operating conditions. Sensitivity studies were performed to determine the influence of the wake fuselage geometry on the computation. Results are presented that describe the induced velocities, pressures, and airloads on the fuselage and on the rotor. The ability to treat arbitrary geometries is demonstrated using a simulated helicopter fuselage. The computational results are compared with fuselage surface pressure measurements at several locations. No experimental data was available to validate the primary product of the analysis: the vibratory airloads on the entire fuselage. A main rotor-tail rotor interaction analysis is also described, along with some hover and forward flight.

  10. Helicopter roll control effectiveness criteria program summary

    NASA Technical Reports Server (NTRS)

    Heffley, Robert K.; Bourne, Simon M.; Mnich, Marc A.

    1988-01-01

    A study of helicopter roll control effectiveness is summarized for the purpose of defining military helicopter handling qualities requirements. The study is based on an analysis of pilot-in-the-loop task performance of several basic maneuvers. This is extended by a series of piloted simulations using the NASA Ames Vertical Motion Simulator and selected flight data. The main results cover roll control power and short-term response characteristics. In general the handling qualities requirements recommended are set in conjunction with desired levels of flight task and maneuver response which can be directly observed in actual flight. An important aspect of this, however, is that vehicle handling qualities need to be set with regard to some quantitative aspect of mission performance. Specific examples of how this can be accomplished include a lateral unmask/remask maneuver in the presence of a threat and an air tracking maneuver which recognizes the kill probability enhancement connected with decreasing the range to the target. Conclusions and recommendations address not only the handling qualities recommendations, but also the general use of flight simulators and the dependence of mission performance on handling qualities.

  11. State-of-the-art cockpit design for the HH-65A helicopters

    NASA Technical Reports Server (NTRS)

    Castleberry, D. E.; Mcelreath, M. Y.

    1982-01-01

    In the design of a HH-65A helicopter cockpit, advanced integrated electronics systems technology was employed to achieve several important goals for this multimission aircraft. They were: (1) integrated systems operation with consistent and simplified cockpit procedures; (2) mission-task-related cockpit displays and controls, and (3) reduced pilot instrument scan effort with excellent outside visibility. The integrated avionics system was implemented to depend heavily upon distributed but complementary processing, multiplex digital bus technology, and multifunction CRT controls and displays. This avionics system was completely flight tested and will soon enter operational service with the Coast Guard.

  12. Crew station research and development facility training for the light helicopter demonstration/validation program

    NASA Technical Reports Server (NTRS)

    Matsumoto, Joy Hamerman; Rogers, Steven; Mccauley, Michael; Salinas, AL

    1992-01-01

    The U.S. Army Crew Station Research and Development Branch (CSRDB) of the Aircraft Simulation Division (AVSCOM) was tasked by the Light Helicopter Program Manager (LH-PM) to provide training to Army personnel in advanced aircraft simulation technology. The purpose of this training was to prepare different groups of pilots to support and evaluate two contractor simulation efforts during the Demonstration/Validation (DEM/VAL) phase of the LH program. The personnel in the CSRDB developed mission oriented training programs to accomplish the objectives, conduct the programs, and provide guidance to army personnel and support personnel throughout the DEM/VAL phase.

  13. Rotorcraft technology at Boeing Vertol: Recent advances

    NASA Technical Reports Server (NTRS)

    Shaw, John; Dadone, Leo; Wiesner, Robert

    1988-01-01

    An overview is presented of key accomplishments in the rotorcraft development at Boeing Vertol. Projects of particular significance: high speed rotor development and the Model 360 Advanced Technology Helicopter. Areas addressed in the overview are: advanced rotors with reduced noise and vibration, 3-D aerodynamic modeling, flight control and avionics, active control, automated diagnostics and prognostics, composite structures, and drive systems.

  14. Sulfate attack expansion mechanisms

    SciTech Connect

    Müllauer, Wolfram Beddoe, Robin E.; Heinz, Detlef

    2013-10-15

    A specially constructed stress cell was used to measure the stress generated in thin-walled Portland cement mortar cylinders caused by external sulfate attack. The effects of sulfate concentration of the storage solution and C{sub 3}A content of the cement were studied. Changes in mineralogical composition and pore size distribution were investigated by X-ray diffraction and mercury intrusion porosimetry, respectively. Damage is due to the formation of ettringite in small pores (10–50 nm) which generates stresses up to 8 MPa exceeding the tensile strength of the binder matrix. Higher sulfate concentrations and C{sub 3}A contents result in higher stresses. The results can be understood in terms of the effect of crystal surface energy and size on supersaturation and crystal growth pressure.

  15. Satellite Threat Warning and Attack Reporting

    SciTech Connect

    Hilland, D.; Phipps, G.; Jingle, C.; Newton, G.

    1997-12-31

    The Air Force Research Laboratory`s Satellite Threat Warning and Attack Reporting (STW/AR) program will provide technologies for advanced threat warning and reporting of radio frequency (RF) and laser threats. The STW/AR program objectives are: (a) develop cost- effective technologies to detect, identify, locate, characterize, and report attacks or interference against U.S. and Allied satellites. (b) demonstrate innovative, light-weight, low-power, laser and RF sensors. The program focuses on the demonstration of RF and laser sensors. The RF sensor effort includes the investigation of interferometric antenna arrays, multi-arm spiral and butler matrix antennas, wideband receivers, adaptive processors, and improved processing algorithms. The laser sensor effort includes the investigation of alternative detectors, broadband grating and optical designs, active pixel sensing, and improved processing algorithms.

  16. Exploiting Small Leakages in Masks to Turn a Second-Order Attack into a First-Order Attack and Improved Rotating Substitution Box Masking with Linear Code Cosets

    PubMed Central

    DeTrano, Alexander; Karimi, Naghmeh; Karri, Ramesh; Guo, Xiaofei; Carlet, Claude; Guilley, Sylvain

    2015-01-01

    Masking countermeasures, used to thwart side-channel attacks, have been shown to be vulnerable to mask-extraction attacks. State-of-the-art mask-extraction attacks on the Advanced Encryption Standard (AES) algorithm target S-Box recomputation schemes but have not been applied to scenarios where S-Boxes are precomputed offline. We propose an attack targeting precomputed S-Boxes stored in nonvolatile memory. Our attack targets AES implemented in software protected by a low entropy masking scheme and recovers the masks with 91% success rate. Recovering the secret key requires fewer power traces (in fact, by at least two orders of magnitude) compared to a classical second-order attack. Moreover, we show that this attack remains viable in a noisy environment or with a reduced number of leakage points. Eventually, we specify a method to enhance the countermeasure by selecting a suitable coset of the masks set. PMID:26491717

  17. Exploiting Small Leakages in Masks to Turn a Second-Order Attack into a First-Order Attack and Improved Rotating Substitution Box Masking with Linear Code Cosets.

    PubMed

    DeTrano, Alexander; Karimi, Naghmeh; Karri, Ramesh; Guo, Xiaofei; Carlet, Claude; Guilley, Sylvain

    2015-01-01

    Masking countermeasures, used to thwart side-channel attacks, have been shown to be vulnerable to mask-extraction attacks. State-of-the-art mask-extraction attacks on the Advanced Encryption Standard (AES) algorithm target S-Box recomputation schemes but have not been applied to scenarios where S-Boxes are precomputed offline. We propose an attack targeting precomputed S-Boxes stored in nonvolatile memory. Our attack targets AES implemented in software protected by a low entropy masking scheme and recovers the masks with 91% success rate. Recovering the secret key requires fewer power traces (in fact, by at least two orders of magnitude) compared to a classical second-order attack. Moreover, we show that this attack remains viable in a noisy environment or with a reduced number of leakage points. Eventually, we specify a method to enhance the countermeasure by selecting a suitable coset of the masks set. PMID:26491717

  18. Importance of engine as a source of helicopter external noise

    NASA Technical Reports Server (NTRS)

    Janakiram, R. D.; Smith, M. J.; Tadghighi, H.

    1989-01-01

    A turboshaft engine's importance as a source of helicopter external noise is presently evaluated experimentally and analytically on the basis of test data from an MD500E helicopter, with and without engine muffler, during level flyovers and climbing flight. A strong engine noise component is noted for helicopter positions nearly overhead and beyond observed position, especially in the 200-1000 Hz range; its strong rearward directivity suggests the noise source to be the broadband exhaust or combustion noise radiated from the exhaust duct. The engine muffler furnished estimated perceived noise level reductions of 2-3 dB for the centerline.

  19. Parametric analysis of a passive cyclic control device for helicopters

    NASA Technical Reports Server (NTRS)

    Kumagai, H.

    1984-01-01

    A parametric study of a passive device which provides a cyclic longitudinal control moment for a helicopter rotor was performed. It utilizes a rotor blade tip which is structurally decoupled from the blade inboard section. This rotor configuration is generally called the Free-Tip Rotor. A two dimensional numerical model was used to review the Constant Lift Tip Rotor, a predecessor of the current configuration, and then the same model was applied to the Passive Cyclic Control Device. The Constant Lift Tip was proven to have the ability to suppress the vibratory lift loading on the tip around the azimuth and to eliminate a significant negative lift peak on the advancing tip. The Passive Cyclic Control Device showed a once-per-revolution lift oscillation with a large amplitude, while minimizing the higher harmonic terms of the lift oscillation. This once-per-revolution oscillation results in the cyclic moment to trim the rotor longitudinally. A rotor performance analysis was performed by a three dimensional numerical model. It indicated that the vortices shed from the junction between the tip and the inboard section has a strong influence on the tip, and it may severely limit the tip performance. It was also shown that the Free-Tip allows the inboard section to have a larger twist, which results in a better performance.

  20. Peripheral processors for high-speed simulation. [helicopter cockpit simulator

    NASA Technical Reports Server (NTRS)

    Karplus, W. J.

    1977-01-01

    This paper describes some of the results of a study directed to the specification and procurement of a new cockpit simulator for an advanced class of helicopters. A part of the study was the definition of a challenging benchmark problem, and detailed analyses of it were made to assess the suitability of a variety of simulation techniques. The analyses showed that a particularly cost-effective approach to the attainment of adequate speed for this extremely demanding application is to employ a large minicomputer acting as host and controller for a special-purpose digital peripheral processor. Various realizations of such peripheral processors, all employing state-of-the-art electronic circuitry and a high degree of parallelism and pipelining, are available or under development. The types of peripheral processors array processors, simulation-oriented processors, and arrays of processing elements - are analyzed and compared. They are particularly promising approaches which should be suitable for high-speed simulations of all kinds, the cockpit simulator being a case in point.

  1. Computer aiding for low-altitude helicopter flight

    NASA Technical Reports Server (NTRS)

    Swenson, Harry N.

    1991-01-01

    A computer-aiding concept for low-altitude helicopter flight was developed and evaluated in a real-time piloted simulation. The concept included an optimal control trajectory-generated algorithm based on dynamic programming, and a head-up display (HUD) presentation of a pathway-in-the-sky, a phantom aircraft, and flight-path vector/predictor symbol. The trajectory-generation algorithm uses knowledge of the global mission requirements, a digital terrain map, aircraft performance capabilities, and advanced navigation information to determine a trajectory between mission waypoints that minimizes threat exposure by seeking valleys. The pilot evaluation was conducted at NASA Ames Research Center's Sim Lab facility in both the fixed-base Interchangeable Cab (ICAB) simulator and the moving-base Vertical Motion Simulator (VMS) by pilots representing NASA, the U.S. Army, and the U.S. Air Force. The pilots manually tracked the trajectory generated by the algorithm utilizing the HUD symbology. They were able to satisfactorily perform the tracking tasks while maintaining a high degree of awareness of the outside world.

  2. Advanced composites for windmills

    NASA Astrophysics Data System (ADS)

    Bourquardez, G.

    A development status assessment is conducted for advanced composite construction techniques for windmill blade structures which, as in the case of composite helicopter rotors, promise greater reliability, longer service life, superior performance, and lower costs. Composites in wind turbine applications must bear aerodynamic, inertial and gravitational loads in complex interaction cycles. Attention is given to large Darrieus-type vertical axis windmills, to which composite construction methods may offer highly effective pitch-control mechanisms, especially in the 'umbrella' configuration.

  3. 78 FR 23688 - Airworthiness Directives; Bell Helicopter Textron Canada Inc. Helicopters

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-22

    ... Policies and Procedures (44 FR 11034, February 26, 1979); 3. Will not affect intrastate aviation in Alaska... Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4; telephone (450) 437-2862 or (800) 363..., contact Bell Helicopter Textron Canada Limited, 12,800 Rue de l'Avenir, Mirabel, Quebec J7J1R4;...

  4. Flight Testing and Real-Time System Identification Analysis of a UH-60A Black Hawk Helicopter with an Instrumented External Sling Load

    NASA Technical Reports Server (NTRS)

    McCoy, Allen H.

    1998-01-01

    Helicopter external air transportation plays an important role in today's world. For both military and civilian helicopters, external sling load operations offer an efficient and expedient method of handling heavy, oversized cargo. With the ability to reach areas otherwise inaccessible by ground transportation, helicopter external load operations are conducted in industries such as logging, construction, and fire fighting, as well as in support of military tactical transport missions. Historically, helicopter and load combinations have been qualified through flight testing, requiring considerable time and cost. With advancements in simulation and flight test techniques there is potential to substantially reduce costs and increase the safety of helicopter sling load certification. Validated simulation tools make possible accurate prediction of operational flight characteristics before initial flight tests. Real time analysis of test data improves the safety and efficiency of the testing programs. To advance these concepts, the U.S. Army and NASA, in cooperation with the Israeli Air Force and Technion, under a Memorandum of Agreement, seek to develop and validate a numerical model of the UH-60 with sling load and demonstrate a method of near real time flight test analysis. This thesis presents results from flight tests of a U.S. Army Black Hawk helicopter with various external loads. Tests were conducted as the U.S. first phase of this MOA task. The primary load was a container express box (CONEX) which contained a compact instrumentation package. The flights covered the airspeed range from hover to 70 knots. Primary maneuvers were pitch and roll frequency sweeps, steps, and doublets. Results of the test determined the effect of the suspended load on both the aircraft's handling qualities and its control system's stability margins. Included were calculations of the stability characteristics of the load's pendular motion. Utilizing CIFER(R) software, a method for near

  5. Metrics for Assessment of Smart Grid Data Integrity Attacks

    SciTech Connect

    Annarita Giani; Miles McQueen; Russell Bent; Kameshwar Poolla; Mark Hinrichs

    2012-07-01

    There is an emerging consensus that the nation’s electricity grid is vulnerable to cyber attacks. This vulnerability arises from the increasing reliance on using remote measurements, transmitting them over legacy data networks to system operators who make critical decisions based on available data. Data integrity attacks are a class of cyber attacks that involve a compromise of information that is processed by the grid operator. This information can include meter readings of injected power at remote generators, power flows on transmission lines, and relay states. These data integrity attacks have consequences only when the system operator responds to compromised data by redispatching generation under normal or contingency protocols. These consequences include (a) financial losses from sub-optimal economic dispatch to service loads, (b) robustness/resiliency losses from placing the grid at operating points that are at greater risk from contingencies, and (c) systemic losses resulting from cascading failures induced by poor operational choices. This paper is focused on understanding the connections between grid operational procedures and cyber attacks. We first offer two examples to illustrate how data integrity attacks can cause economic and physical damage by misleading operators into taking inappropriate decisions. We then focus on unobservable data integrity attacks involving power meter data. These are coordinated attacks where the compromised data are consistent with the physics of power flow, and are therefore passed by any bad data detection algorithm. We develop metrics to assess the economic impact of these attacks under re-dispatch decisions using optimal power flow methods. These metrics can be use to prioritize the adoption of appropriate countermeasures including PMU placement, encryption, hardware upgrades, and advance attack detection algorithms.

  6. Helicopter transmission arrangements with split-torque gear trains

    NASA Technical Reports Server (NTRS)

    White, G.

    1983-01-01

    As an alternative to component development, the case for improved drive-train configuration is argued. In particular, the use of torque-splitting gear trains is proposed as a practicable means of improving the effectiveness of helicopter main gearboxes.

  7. Overview of the Colorado River Canyon from the helicopter pad. ...

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

    Overview of the Colorado River Canyon from the helicopter pad. View of the Nevada side where new bridge will cross canyon, view northwest - Hoover Dam, Spanning Colorado River at Route 93, Boulder City, Clark County, NV

  8. 7. Shed and keeper' house with helicopter pad in foreground, ...

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

    7. Shed and keeper' house with helicopter pad in foreground, view east, southwest and northwest sides - Goat Island Light Station, Goat Island, next to entrance to Cape Porpoise Harbor, just south of Trott Island, Cape Porpoise, York County, ME

  9. 10. Helicopter pad, fire extinguisher at center, looking southwest ...

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

    10. Helicopter pad, fire extinguisher at center, looking southwest - Ellsworth Air Force Base, Delta Flight, Launch Control Facility, County Road CS23A, North of Exit 127, Interior, Jackson County, SD

  10. Component noise variables of a light observation helicopter

    NASA Technical Reports Server (NTRS)

    Robinson, F.

    1973-01-01

    A test program was conducted to isolate and evaluate the individual noise sources of a light helicopter. To accomplish this, the helicopter was mounted on a special test rig, at a 6-foot skid height, in a simulated hover. The test rig contained by dynamometer for absorbing engine power and an exhaust silencing system for reducing engine noise. This test set-up allowed the various components of the helicopter to be run and listened to individually or in any combination. The sound pressure level was recorded at a point 200 feet from the helicopter as the component parameters were systematically varied. The tests were conducted in an open area, during the middle of the night, with no wind, and with all other known variables either eliminated or kept as constant as possible.

  11. Astronauts L. Gordon Cooper Jr. hoisted up to Navy helicopter

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronaut L. Gordon Cooper Jr. is hoisted up to a Navy helicopter during recovery operations in the Atlantic Ocean of the Gemini 5 spacecraft. The NASA Headquarter alternative photo number is 65-H-688.

  12. A practical approach to helicopter internal noise prediction

    NASA Technical Reports Server (NTRS)

    Levine, L. S.; Defelice, J. J.

    1978-01-01

    A practical and well correlated procedure for predicting helicopter internal noise is presented. It accounts for the propagation of noise along multiple paths on an octave by octave basis. The method is sufficiently general to be applicable to conventional helicopters as well as other aircraft types, when the appropriate structural geometry, noise source strengths, and material acoustic properties are defined. A guide is provided for the prediction of various helicopter noise sources over a wide range of horsepower for use when measured data are not available. The method is applied to the prediction of the interior levels of the Civil Helicopter Research Aircraft (CHRA), both with and without soundproofing installed. Results include good correlation with measured levels and prediction of the speech interference level within 1.5 db at all conditions. A sample problem is also shown illustrating the use of the procedure. This example calculates the engine casing noise observed in the passenger cabin of the CHRA.

  13. Vibratory Loads Data from a Wind-Tunnel Test of Structurally Tailored Model Helicopter Rotors

    NASA Technical Reports Server (NTRS)

    Yeager, William T., Jr.; Hamouda, M-Nabil H.; Idol, Robert F.; Mirick, Paul H.; Singleton, Jeffrey D.; Wilbur, Matthew L.

    1991-01-01

    An experimental study was conducted in the Langley Transonic Dynamics Tunnel to investigate the use of a Bell Helicopter Textron (BHT) rotor structural tailoring concept, known as rotor nodalization, in conjunction with advanced blade aerodynamics as well as to evaluate rotor blade aerodynamic design methodologies. A 1/5-size, four-bladed bearingless hub, three sets of Mach-scaled model rotor blades were tested in forward flight from transition up to an advance ratio of 0.35. The data presented pertain only to the evaluation of the structural tailoring concept and consist of fixed-system and rotating system vibratory loads. These data will be useful for evaluating the effects of tailoring blade structural properties on fixed-system vibratory loads, as well as validating analyses used in the design of advanced rotor systems.

  14. Helicopter Model Rotor-Blade Vortex Interaction Impulsive Noise: Scalability and Parametric Variations

    NASA Technical Reports Server (NTRS)

    Boxwell, D. A.; Schmitz, F. H.; Splettstoesser, W. R.; Schultz, K. J.

    1987-01-01

    Acoustic data taken in the anechoic Deutsch-Niederlaendischer Windkanal (DNW) have documented the blade-vortex interaction (BVI) impulsive noise radiated from a 1/7-scale model main rotor of the AH-1 series helicopter. Averaged model-scale data were compared with averaged full-scale, in-flight acoustic data under similar non-dimensional test conditions using an improved data analysis technique. At low advance ratios (mu = 0.164 - 0.194), the BVI impulsive noise data scale remarkably well in level, waveform, and directivity patterns. At moderate advance ratios (mu = 0.224 - 0.270), the scaling deteriorates, suggesting that the model-scale rotor is not adequately simulating the full-scale BVI noise. Presently, no proved explanation of this discrepancy exists. Measured BVI noise radiation is highly sensitive to all of the four governing nondimensional parameters--hover tip Mach number, advance ratio, local inflow ratio, and thrust coefficient.

  15. Astronauts Stafford and Young await pickup by recovery helicopter

    NASA Technical Reports Server (NTRS)

    1969-01-01

    Astronauts Thomas P. Stafford, commander; and John W. Young, command module pilot, await pickup by the recovery helicopter from the prime recovery ship, U.S.S. Pinceton. Astronaut Eugene A. Cernan, lunar module pilot, is already hoisted aboard the helicopter. U.S. Navy underwater demolition team swimmers assist in the recovery operations. Splashdown occurred at 11:53 a.m., May 26, 1969, about 400 miles east of American Samoa.

  16. Helicopter technology benefits and needs. Volume 2: Appendices

    NASA Technical Reports Server (NTRS)

    Zuk, J.; Adams, R. J.

    1980-01-01

    Vehicle design, avionics and flight systems; safety and reliability; navigation, guidance and flight control; propulsion; auxiliary systems; human factors; and monitoring and diagnostic systems are the technology areas involved in solving operational and technical problems related to the use of helicopters. Tables show the problems encountered and the proposed research and technology for helicopter use for search and rescue; emergency medical services; law enforcement; environmental control; fire fighting; and resource management.

  17. Design development tests for composite crashworthy helicopter fuselage

    SciTech Connect

    Sen, J.K.; Dremann, C.C.

    1985-10-01

    Design development tests were conducted to investigate the crashworthy characteristics of composite helicopter fuselage subcomponents, and to design helicopter center beam/bulkhead specimens lighter than structural elements of honeycomb sandwich construction. Skinstringer designs of center beams - made of carbon, and hybrids of carbon and Kevlar - were fabricated and tested in axial compression. Crashworthy design parameters of specific energy, operating load and stroke efficiency were investigated. 8 references, 15 figures, 2 tables.

  18. Helicopter crash in water: effects of simulator escape training.

    PubMed

    Hytten, K

    1989-01-01

    Findings are presented from an interview study of five crew members who survived a helicopter crash. Four of the five surviving men had received simulated helicopter accident training prior to the crash. One untrained crew member died. The four previously trained survivors claimed that the training was of decisive moment in their escape and survival. Contributions from training appeared to be provision of confidence and thought control. The author discusses these as the development of a positive response-outcome expectancy.

  19. Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads

    NASA Technical Reports Server (NTRS)

    Amer, K. B.; Neff, J. R.

    1974-01-01

    The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed.

  20. Design guide for helicopter transmission seals

    NASA Technical Reports Server (NTRS)

    Hayden, T. S.; Keller, C. H., Jr.

    1974-01-01

    A detailed approach for the selection and design of seals for helicopter transmissions is presented. There are two major types of seals presently being used and they are lip type seals and mechanical type seals. Lip type seals can be divided in conventional lip seals and hydrodynamic lip seals. Conventional lip seals can be used for slow-speed, low-pressure, low-temperature sealing. Hydrodynamic lip seals although they are as pressure and temperature limited as conventional lip seals, can operate at a higher speed. Mechanical types seals are comprised of face seals and circumferential seals. Face seals are capable of high speed, high pressure, and high temperature. Circumferential seals can be used in high-speed and high-temperature applications, but will leak excessively at moderate pressures. The performance goals of transmission seals are a life that is at least equal to the scheduled overhaul interval of the gearbox component and a leakage rate of near zero.

  1. Helicopter mishap attributed to single seizure.

    PubMed

    Simon, Esan; Watts, Darron; Bohnker, Bruce K

    2008-03-01

    A case report is presented of a 36-year-old U.S. Coast Guard aviator who had a single seizure while operating a helicopter on the ground. His seizure activity produced a loss of consciousness during which he pushed the cyclic to the left anterior quadrant that resulted in a ground mishap. No risk factors were identified in an extensive neurological workup. The current guidance for handling seizures in military aviation personnel is reviewed, along with considerations for treatment. Although the military aviation selection process carefully screens applicants for seizure history and potential, occasional seizures in the aviation population remain possible. Such events may result in military aircraft mishaps despite careful risk factor surveillance, as demonstrated by this case.

  2. Deicing of helicopter blades using piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Ramanathan, Srinivasa; Varadan, Vasundara V.; Varadan, Vijay K.

    2000-06-01

    Deicing of fixed wing aircraft and rotor craft that fly; at lower altitudes has been an area of research interest for many decades. The currently available solutions, though functional, are economically or environmentally inefficient. Some military helicopters have electrical deicing system for rotor blades that use up to 12 kW of power to achieve all weather shear horizontal waves at the ice-substrate interface is proposed. Experiments were carried out using PZT-5A and PZT-8 shear plate actuators bonded to an aluminum plate. A low-temperature chamber was constructed for this purpose. The results indicate that the PZT-8 actuators were able to deice the aluminum plate melting the ice at the interface. Results are presented in the form of tabular data and digital photographs taken of the melting process. The deicing mechanism is discussed.

  3. An evaluation of three helicopter rotor sections

    NASA Technical Reports Server (NTRS)

    Hicks, R. M.; Collins, L. J.

    1985-01-01

    Three helicopter rotor sections were tested in the NASA Ames Research Center 2- by 2-Foot Transonic Wind Tunnel over a Mach range from 0.2 to 0.88. The sections tested had maximum thickness/chord ratios of 0.078, 0.09, and 0.10. The thickest section was of early technology and had been tested previously in other wind tunnels. This section was included in the investigation to establish a basis for comparing the two thinner sections, which were of recent design. The results of the investigation showed that the pitching-moment characteristics for the three airfoil sections were acceptable. The drag divergence Mach numbers for the three sections were 0.80, 0.825, and 0.845 in order of decreasing thickness.

  4. Study of design constraints on helicopter noise

    NASA Technical Reports Server (NTRS)

    Sternfeld, H., Jr.; Wiedersum, C. W.

    1979-01-01

    A means of estimating the noise generated by a helicopter main rotor using information which is generally available during the preliminary design phase of aircraft development is presented. The method utilizes design charts and tables which do not require an understanding of acoustical theory or computational procedures in order to predict the perceived noise level, a weighted sound pressure level, or C weighted sound pressure level of a single hovering rotor. A method for estimating the effective perceived noise level in forward flight is also included. In order to give the designer an assessment of the relative rotor performance, which may be traded off against noise, an additional chart for estimating the percent of available rotor thrust which must be expended in lifting the rotor and drive system, is included as well as approach for comparing the subjective acceptability of various rotors once the absolute sound pressure levels are predicted.

  5. Development of adaptive helicopter seat systems for aircrew vibration mitigation

    NASA Astrophysics Data System (ADS)

    Chen, Yong; Wickramasinghe, Viresh; Zimcik, David G.

    2008-03-01

    Helicopter aircrews are exposed to high levels of whole body vibration during flight. This paper presents the results of an investigation of adaptive seat mount approaches to reduce helicopter aircrew whole body vibration levels. A flight test was conducted on a four-blade helicopter and showed that the currently used passive seat systems were not able to provide satisfactory protection to the helicopter aircrew in both front-back and vertical directions. Long-term exposure to the measured whole body vibration environment may cause occupational health issues such as spine and neck strain injuries for aircrew. In order to address this issue, a novel adaptive seat mount concept was developed to mitigate the vibration levels transmitted to the aircrew body. For proof-of-concept demonstration, a miniature modal shaker was properly aligned between the cabin floor and the seat frame to provide adaptive actuation authority. Adaptive control laws were developed to reduce the vibration transmitted to the aircrew body, especially the helmet location in order to minimize neck and spine injuries. Closed-loop control test have been conducted on a full-scale helicopter seat with a mannequin configuration and a large mechanical shaker was used to provide representative helicopter vibration profiles to the seat frame. Significant vibration reductions to the vertical and front-back vibration modes have been achieved simultaneously, which verified the technical readiness of the adaptive mount approach for full-scale flight test on the vehicle.

  6. Steady and Periodic Pressure Measurements on a Generic Helicopter Fuselage Model in the Presence of a Rotor

    NASA Technical Reports Server (NTRS)

    Mineck, Raymond E.; Gorton, Susan A.

    2000-01-01

    A wind tunnel test of a generic helicopter fuselage model with an independently mounted rotor has been conducted to obtain steady and periodic pressure data on the helicopter body. The model was tested at four advance ratios and three thrust coefficients. The periodic unsteady pressure coefficients are marked by four peaks associated with the passage of the four rotor blades. Blade passage effects are largest on the nose and tail boom of the model. The magnitude of the pulse increases with rotor thrust coefficient. Tabular listings of the unsteady pressure data are included to permit independent analysis. A CD-rom containing the steady and unsteady pressure data presented in the report is available from the authors.

  7. Low-noise, high-strength, spiral-bevel gears for helicopter transmissions

    NASA Technical Reports Server (NTRS)

    Lewicki, David G.; Handschuh, Robert F.; Henry, Zachary S.; Litvin, Faydor L.

    1993-01-01

    Improvements in spiral-bevel gear design were investigated to support the Army/NASA Advanced Rotorcraft Transmission program. Program objectives were to reduce weight by 25 percent, reduce noise by 10 dB, and increase life to 5000 hr mean-time-between-removal. To help meet these goals, advanced-design spiral-bevel gears were tested in an OH-58D helicopter transmission using the NASA 500-hp Helicopter Transmission Test Stand. Three different gear designs tested included: (1) the current design of the OH-58D transmission except gear material X-53 instead of AISI 9310; (2) a higher-strength design the same as the current but with a full fillet radius to reduce gear tooth bending stress (and thus, weight); and (3) a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.

  8. Low-noise, high-strength, spiral-bevel gears for helicopter transmissions

    SciTech Connect

    Lewicki, D.G.; Handschuh, R.F.; Henry, Z.S.; Litvin, F.L.

    1993-06-01

    Improvements in spiral-bevel gear design were investigated to support the Army/NASA Advanced Rotorcraft Transmission program. Program objectives were to reduce weight by 25 percent, reduce noise by 10 dB, and increase life to 5000 hr mean-time-between-removal. To help meet these goals, advanced-design spiral-bevel gears were tested in an OH-58D helicopter transmission using the NASA 500-hp Helicopter Transmission Test Stand. Three different gear designs tested included: (1) the current design of the OH-58D transmission except gear material X-53 instead of AISI 9310; (2) a higher-strength design the same as the current but with a full fillet radius to reduce gear tooth bending stress (and thus, weight); and (3) a lower-noise design the same as the high-strength but with modified tooth geometry to reduce transmission error and noise. Noise, vibration, and tooth strain tests were performed and significant gear stress and noise reductions were achieved.

  9. WILD PIG ATTACKS ON HUMANS

    SciTech Connect

    Mayer, J.

    2013-04-12

    Attacks on humans by wild pigs (Sus scrofa) have been documented since ancient times. However, studies characterizing these incidents are lacking. In an effort to better understand this phenomenon, information was collected from 412 wild pig attacks on humans. Similar to studies of large predator attacks on humans, data came from a variety of sources. The various attacks compiled occurred in seven zoogeographic realms. Most attacks occurred within the species native range, and specifically in rural areas. The occurrence was highest during the winter months and daylight hours. Most happened under non-hunting circumstances and appeared to be unprovoked. Wounded animals were the chief cause of these attacks in hunting situations. The animals involved were typically solitary, male and large in size. The fate of the wild pigs involved in these attacks varied depending upon the circumstances, however, most escaped uninjured. Most human victims were adult males traveling on foot and alone. The most frequent outcome for these victims was physical contact/mauling. The severity of resulting injuries ranged from minor to fatal. Most of the mauled victims had injuries to only one part of their bodies, with legs/feet being the most frequent body part injured. Injuries were primarily in the form of lacerations and punctures. Fatalities were typically due to blood loss. In some cases, serious infections or toxemia resulted from the injuries. Other species (i.e., pets and livestock) were also accompanying some of the humans during these attacks. The fates of these animals varied from escaping uninjured to being killed. Frequency data on both non-hunting and hunting incidents of wild pig attacks on humans at the Savannah River Site, South Carolina, showed quantitatively that such incidents are rare.

  10. RSRA sixth scale wind tunnel test. [of scale model of Sikorsky Whirlwind Helicopter

    NASA Technical Reports Server (NTRS)

    Flemming, R.; Ruddell, A.

    1974-01-01

    The sixth scale model of the Sikorsky/NASA/Army rotor systems research aircraft was tested in an 18-foot section of a large subsonic wind tunnel for the purpose of obtaining basic data in the areas of performance, stability, and body surface loads. The model was mounted in the tunnel on the struts arranged in tandem. Basic testing was limited to forward flight with angles of yaw from -20 to +20 degrees and angles of attack from -20 to +25 degrees. Tunnel test speeds were varied up to 172 knots (q = 96 psf). Test data were monitored through a high speed static data acquisition system, linked to a PDP-6 computer. This system provided immediate records of angle of attack, angle of yaw, six component force and moment data, and static and total pressure information. The wind tunnel model was constructed of aluminum structural members with aluminum, fiberglass, and wood skins. Tabulated force and moment data, flow visualization photographs, tabulated surface pressure data are presented for the basic helicopter and compound configurations. Limited discussions of the results of the test are included.

  11. TCPL: A Defense against wormhole attacks in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Kumar, K. E. Naresh; Waheed, Mohd. Abdul; Basappa, K. Kari

    2010-10-01

    Do In this paper presents recent advances in technology have made low-cost, low-power wireless sensors with efficient energy consumption. A network of such nodes can coordinate among themselves for distributed sensing and processing of certain data. For which, we propose an architecture to provide a stateless solution in sensor networks for efficient routing in wireless sensor networks. This type of architecture is known as Tree Cast. We propose a unique method of address allocation, building up multiple disjoint trees which are geographically inter-twined and rooted at the data sink. Using these trees, routing messages to and from the sink node without maintaining any routing state in the sensor nodes is possible. In this paper, we introduce the wormhole attack, a severe attack in ad hoc networks that is particularly challenging to defend against. The wormhole attack is possible even if the attacker has not compromised any hosts and even if all communication provides authenticity and confidentiality. In the wormhole attack, an attacker records packets (or bits) at one location in the network, tunnels them to another location, and retransmits them there into the network. The wormhole attack can form a serious threat in wireless networks, especially against many sensor network routing protocols and location-based wireless security systems. For example, most existing ad hoc network routing protocols, without some mechanism to defend against the wormhole attack, would be unable to find routes longer than one or two hops, severely disrupting communication. We present a new, general mechanism, called packet leashes, for detecting and thus defending against wormhole attacks, and we present a specific protocol, called TIK, that implements leashes.

  12. TCPL: A Defense against wormhole attacks in wireless sensor networks

    SciTech Connect

    Kumar, K. E. Naresh; Waheed, Mohd. Abdul; Basappa, K. Kari

    2010-10-26

    Do In this paper presents recent advances in technology have made low-cost, low-power wireless sensors with efficient energy consumption. A network of such nodes can coordinate among themselves for distributed sensing and processing of certain data. For which, we propose an architecture to provide a stateless solution in sensor networks for efficient routing in wireless sensor networks. This type of architecture is known as Tree Cast. We propose a unique method of address allocation, building up multiple disjoint trees which are geographically inter-twined and rooted at the data sink. Using these trees, routing messages to and from the sink node without maintaining any routing state in the sensor nodes is possible. In this paper, we introduce the wormhole attack, a severe attack in ad hoc networks that is particularly challenging to defend against. The wormhole attack is possible even if the attacker has not compromised any hosts and even if all communication provides authenticity and confidentiality. In the wormhole attack, an attacker records packets (or bits) at one location in the network, tunnels them to another location, and retransmits them there into the network. The wormhole attack can form a serious threat in wireless networks, especially against many sensor network routing protocols and location-based wireless security systems. For example, most existing ad hoc network routing protocols, without some mechanism to defend against the wormhole attack, would be unable to find routes longer than one or two hops, severely disrupting communication. We present a new, general mechanism, called packet leashes, for detecting and thus defending against wormhole attacks, and we present a specific protocol, called TIK, that implements leashes.

  13. Advanced electromagnetic methods for aerospace vehicles

    NASA Technical Reports Server (NTRS)

    Balanis, Constantine A.; Sun, Weimin; El-Sharawy, El-Budawy; Aberle, James T.; Birtcher, Craig R.; Peng, Jian; Tirkas, Panayiotis A.

    1992-01-01

    The Advanced Helicopter Electromagnetics (AHE) Industrial Associates Program continues its research on variety of main topics identified and recommended by the Advisory Task Force of the program. The research activities center on issues that advance technology related to helicopter electromagnetics. While most of the topics are a continuation of previous works, special effort has been focused on some of the areas due to recommendations from the last annual conference. The main topics addressed in this report are: composite materials, and antenna technology. The area of composite materials continues getting special attention in this period. The research has focused on: (1) measurements of the electrical properties of low-conductivity materials; (2) modeling of material discontinuity and their effects on the scattering patterns; (3) preliminary analysis on interaction of electromagnetic fields with multi-layered graphite fiberglass plates; and (4) finite difference time domain (FDTD) modeling of fields penetration through composite panels of a helicopter.

  14. Genetic attack on neural cryptography.

    PubMed

    Ruttor, Andreas; Kinzel, Wolfgang; Naeh, Rivka; Kanter, Ido

    2006-03-01

    Different scaling properties for the complexity of bidirectional synchronization and unidirectional learning are essential for the security of neural cryptography. Incrementing the synaptic depth of the networks increases the synchronization time only polynomially, but the success of the geometric attack is reduced exponentially and it clearly fails in the limit of infinite synaptic depth. This method is improved by adding a genetic algorithm, which selects the fittest neural networks. The probability of a successful genetic attack is calculated for different model parameters using numerical simulations. The results show that scaling laws observed in the case of other attacks hold for the improved algorithm, too. The number of networks needed for an effective attack grows exponentially with increasing synaptic depth. In addition, finite-size effects caused by Hebbian and anti-Hebbian learning are analyzed. These learning rules converge to the random walk rule if the synaptic depth is small compared to the square root of the system size.

  15. Genetic attack on neural cryptography

    SciTech Connect

    Ruttor, Andreas; Kinzel, Wolfgang; Naeh, Rivka; Kanter, Ido

    2006-03-15

    Different scaling properties for the complexity of bidirectional synchronization and unidirectional learning are essential for the security of neural cryptography. Incrementing the synaptic depth of the networks increases the synchronization time only polynomially, but the success of the geometric attack is reduced exponentially and it clearly fails in the limit of infinite synaptic depth. This method is improved by adding a genetic algorithm, which selects the fittest neural networks. The probability of a successful genetic attack is calculated for different model parameters using numerical simulations. The results show that scaling laws observed in the case of other attacks hold for the improved algorithm, too. The number of networks needed for an effective attack grows exponentially with increasing synaptic depth. In addition, finite-size effects caused by Hebbian and anti-Hebbian learning are analyzed. These learning rules converge to the random walk rule if the synaptic depth is small compared to the square root of the system size.

  16. Attack vulnerability of complex networks

    NASA Astrophysics Data System (ADS)

    Holme, Petter; Kim, Beom Jun; Yoon, Chang No; Han, Seung Kee

    2002-05-01

    We study the response of complex networks subject to attacks on vertices and edges. Several existing complex network models as well as real-world networks of scientific collaborations and Internet traffic are numerically investigated, and the network performance is quantitatively measured by the average inverse geodesic length and the size of the largest connected subgraph. For each case of attacks on vertices and edges, four different attacking strategies are used: removals by the descending order of the degree and the betweenness centrality, calculated for either the initial network or the current network during the removal procedure. It is found that the removals by the recalculated degrees and betweenness centralities are often more harmful than the attack strategies based on the initial network, suggesting that the network structure changes as important vertices or edges are removed. Furthermore, the correlation between the betweenness centrality and the degree in complex networks is studied.

  17. 14 CFR Appendix H to Part 36 - Noise Requirements For Helicopters Under Subpart H

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... instrumentation. Applicable independent systems are radar tracking, theodolite triangulation, laser trajectography, photo scaling, or differential global positioning system. (3) The helicopter position along the flight... signals recorded at an approved sampling rate. The helicopter position must be recorded relative to...

  18. 33 CFR 149.418 - What fire protection system must a helicopter fueling facility have?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... system complying with 46 CFR 108.489. ... a helicopter fueling facility have? 149.418 Section 149.418 Navigation and Navigable Waters COAST... protection system must a helicopter fueling facility have? In addition to the portable fire...

  19. 33 CFR 149.418 - What fire protection system must a helicopter fueling facility have?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... with 46 CFR 108.489. ... a helicopter fueling facility have? 149.418 Section 149.418 Navigation and Navigable Waters COAST... protection system must a helicopter fueling facility have? In addition to the portable fire...

  20. 33 CFR 149.418 - What fire protection system must a helicopter fueling facility have?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... system complying with 46 CFR 108.489. ... a helicopter fueling facility have? 149.418 Section 149.418 Navigation and Navigable Waters COAST... protection system must a helicopter fueling facility have? In addition to the portable fire...