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  • AIRCRAFT  (324)
  • AERODYNAMICS
  • 1970-1974  (576)
  • 1925-1929
  • 1972  (576)
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  • 1970-1974  (576)
  • 1925-1929
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  • 1
    Publication Date: 2005-11-30
    Description: Wind tunnel tests to determine the aerodynamic characteristics of basically similar short takeoff aircraft were conducted. The investigations were designed to provide data for a systematic direct comparison of five of the concepts considered. The configurations of the five models are illustrated and described. The aerodynamic data are presented in the form of graphs. It was concluded that the most complex systems require the least amount of net thrust.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center STOL Technol.; p 111-120
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  • 2
    Publication Date: 2005-11-30
    Description: Analysis, design, experimental static testing, wind-tunnel testing, and design integration studies are used to develop an augmentor wing jet flap configuration for a jet STOL transport aircraft having maximum propulsion and aerodynamic performance with minimum noise generation. The program has three basic elements: (1) static testing of a scale wing section to demonstrate augmentor performance and noise characteristics; (2) two-dimensional wind-tunnel testing to determine flight-speed effects on performance, and (3) system design and evaluation that optimizes the complete system and ensures that the design is compatible with the requirements for a large STOL transport having a 500-foot sideline noise of 95 perceived noise decibels (PNdb) or less.
    Keywords: AIRCRAFT
    Type: NASA. Lewis Res. Center Aircraft Engine Noise Reduction; p 291-304
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  • 3
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    In:  CASI
    Publication Date: 2005-11-30
    Description: A description of the performance test to compare noise output from a quiet engine with acoustic nacelle to the noise output of the JT3D turbofan engine is presented. Tabulations depict comparative thrusts, bypass ratios, core jet velocities, and fan jet velocities for both engines during simulated takeoff and approach performances.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 215-218
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  • 4
    Publication Date: 2005-11-30
    Description: The principal suppressor parameters and their relationships have been used to formulate a suppressor design methodology which has been applied to the design of several full-scale suppressors. Tests of these suppressors on several full-scale fans have demonstrated noise reductions of the order of 10 PNdB. The amount of suppression in several instances seems to have been limited by reaching noise floors that are not clearly at the estimated jet noise level but are not far above it. In addition to identifying noise floors, two other areas are considered. The first is attenuation by the fan exhaust suppressors, which seems in most cases to be less than that of the inlet. The second is the effectiveness of outer cowl treatment alone on multiple pure tones. This question relates to whether a high-speed fan can become as quiet as a low-speed fan without a substantial increase in the amount of treatment.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 63-102
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  • 5
    Publication Date: 2005-11-30
    Description: Externally-blown-flap noise research can be summarized by the following remarks: With lower-surface blowing, the sources of the flap noise are begining to be understood and the noise scaling laws have been established. Further, progress has been made on suppressing the flap interaction noise at the large flap deflections used during landing. Recent small-scale noise tests of configurations using external upper-surface blowing indicate that engine-over-the-wing configurations may be promising.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 259-290
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  • 6
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    In:  CASI
    Publication Date: 2005-11-30
    Description: STOL noise goals, noise sources, and their affects on engine and propulsion systems design are considered. It is shown that major noise sources constitute the blown-flap system with its turbofan engine and the augmentor wing propulsion system. Most of the problem areas associated with STOL propulsion systems are defined and the development of a multistage fan engine with proper rotor-stator spacings and low noise core exhaust jet is illustrated. A variable-area acoustic inlet provides near sonic flow conditions during takeoff and landing.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 247-258
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  • 7
    Publication Date: 2005-11-30
    Description: The acoustic and aerodynamic test results obtained with the two quiet engines are given in this presentation. Some of the test results reviewed include the performance of the untreated or baseline quiet engines. In addition, test results are shown for various degrees and areas of engine acoustic treatment. Finally, the results obtained on a flight-type, acoustically treated nacelle added to one of the quiet engines is examined.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 183-214
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  • 8
    Publication Date: 2005-11-30
    Description: Estimates of the prospects for quiet airplanes in the future are summarized. The SST using afterburning turbojets and no sound suppression is estimated to produce 129 EPNdb on the sideline. Suppression devices and operating techniques can reduce this noise markedly. The present fleet of 707's and DC-8's produces noises nearly as high as 120 decibels on approach. Combinations of sound absorbing devices and engine modifications are expected to give a noise near 100 decibels. The new advanced technology transports (ATT) are being studied with two noise goals in mind: one is 10 decibels and the other is 20 decibels below the FAR level of 106 on takeoff. New trijets using new quiet engines are expected to meet 90 EPNdb. Future advances in technology are expected to yield another 5 decibels to give noise levels of 80 EPNdb. The STOL airplane has a noise goal of 95 EPNdb along a sideline 500 feet from the runway.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 219-246
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  • 9
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    In:  CASI
    Publication Date: 2005-11-30
    Description: The static program has shown to date that very large noise reductions can be achieved by the sonic inlet concept with realistic inlet length and good aerodynamic performance. It is also shown that different inlet concepts produce substantially different results.
    Keywords: AIRCRAFT
    Type: NASA. Lewis Res. Center Aircraft Engine Noise Reduction; p 305-317
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  • 10
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Three high performance fans were designed, built, and tested, accumulating 444 hours. All three fans are both aerodynamically and mechanically suitable for direct incorporation into engine applications. Two turbofan demonstrators to evaluate both low- and high-speed fan systems were also designed, built, and tested. All components and engine systems are demonstrating high reliability. These components have demonstrated advanced state-of-the-art in acoustics, aerodynamics, and mechanical design.
    Keywords: AIRCRAFT
    Type: NASA. Lewis Res. Center Aircraft Engine Noise Reduction; p 143-162
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  • 11
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Estimates of noise reductions for high bypass ratio engines show that bypass ratio fan noise increases with increasing bypass ratio and dominates above a bypass ratio of about 1.0. Fan noise reduction to the level of jet noise is achieved by elimination of inlet guide vanes, elimination of second fan stage, and increased spacing between rotor and stator. Quiet engine design studies show that, at bypass ratios near 5 or 6 and with low noise fans, noise reductions in the order of 15 to 20 decibels relative to DC-8 and 707 airplanes engines are possible.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 139-142
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  • 12
    Publication Date: 2005-11-30
    Description: Tradeoffs between aerodynamic and acoustic properties of various fan configurations led to the selection of a variety of fans that produce noise levels in the range of 100 to 120 PNdb. Fan configuration and design pressure ratio required for specific mission operations depend in part on the type of mission to be performed. Noise data obtained for single-stage low speed fans, single-stage high speed fans, and two-stage fan engines are presented in table form.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 7-61
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  • 13
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Reduction of fan noise emanating from turbofan engines by using acoustically treated nacelles is considered. Test performance prediction for an acoustically lined nacelle having a three ring inlet, a single ring fan duct, and external cowling expect a 15 PNdb fan noise reduction with 5 percent takeoff thrust loss and a 5.4 percent cruise specific fuel consumption increase.
    Keywords: AIRCRAFT
    Type: NASA. Lewis Res. Center Aircraft Engine Noise Reduction; p 163-181
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  • 14
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Progress reported on principle NASA programs for the reduction of aircraft engine noise emphasizes the Quiet Engine Program. Considered are fan noise and performance, fan noise suppression, and jet noise reduction for a broad spectrum of airplanes including new subsonic airplanes, the older subsonic airplanes in service today, STOL airplanes of the future, and future supersonic transports. Noise reductions achieved in the framework of the Quiet Engine Program are demonstrated and future possible applications of low noise technology to airplanes are discussed.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 1-5
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  • 15
    Publication Date: 2005-11-30
    Description: The vibration environment in a wide range of aerospace and surface vehicles is examined, and definitions related to ride evaluation are reviewed. Three provinces of research and application of ride data are recognized: (1) ride affecting passenger and operator comfort; (2) ride affecting human efficiency; and (3) ride affecting the health and safety of occupants occupationally or repeatedly exposed. Specific reference is made to the proposed ISO guide on human exposure to whole-body vibration. The applications as well as the advantages and limitations of this guide for evaluating vehicle ride are discussed. The derivation of the limits is reviewed with regard to the supporting data and the compromises necessary for wide applicability. Special discussions are included of the frequency and time dependence of these limits and approaches in progress for adjusting them according to different criteria of application.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Symp. on Vehicle Ride Quality; p 175-196
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  • 16
    Publication Date: 2005-11-30
    Description: The problem of in-flight aerodynamic noise has been studied by reliable estimates of full scale surface-pressure fluctuations from scale model tests in wind tunnels. Scaling relationships have been verified, and many details of the fluctuating pressure characteristics such as spatial correlation and convection velocities are understood. The effects of the wind tunnel environmental turbulence and noise have also been investigated sufficiently so that threshold levels of usable data are known.
    Keywords: AERODYNAMICS
    Type: NASA Space Shuttle Technol. Conf.; p 71-96
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  • 17
    Publication Date: 2005-11-30
    Description: The main conclusions reached are: (1) At low subsonic jet exhaust velocities, jet noise varies as the velocity to the eighth power; (2) at high subsonic exhaust velocities, jet noise approaches a variation with velocity to the third power; (3) use of the jet density squared overcorrects density effects on jet noise; (4) subsonic and supersonic jet noise levels can be predicted; and (6) use of multielement nozzles and acoustically lined ejectors significantly suppress jet noise at intermediate jet exhaust velocities.
    Keywords: AIRCRAFT
    Type: Aircraft Engine Noise Reduction; p 103-137
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  • 18
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    In:  CASI
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 121-133
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  • 19
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 97-110
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  • 20
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    In:  CASI
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 49-58
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  • 21
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 71-84
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  • 22
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 85-96
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  • 23
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 1-12
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  • 24
    Publication Date: 2004-12-03
    Keywords: AERODYNAMICS
    Type: Supercritical Wing Technol.: A Report on Flight Evaluation; p 35-48
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  • 25
    Publication Date: 2006-04-26
    Description: A flight test experiment is described, in which various aspects of ride qualities were explored. Situations included simulated cruise and terminal area maneuvers, as might be typical of STOL transport operations. Various motion components were studied in isolation and in many combinations. The experiment included runs with and without turbulence, variations in airplane stability and handling qualities, and differences of pilot technique. The ride quality was strongly affected by roll, yaw, and heave motions; but very little by pitching. It was strongly affected by airplane stability and handling qualities and, in some cases, by piloting technique.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Symp. on Vehicle Ride Quality; p 67-89
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  • 26
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    In:  CASI
    Publication Date: 2006-04-26
    Description: An analysis of the factors which affect riding comfort in various modes of transportation is presented. The subjects discussed are: (1) human factor elements in ride quality, (2) current knowledge of flight dynamics and relation to passenger acceptance, (3) study requirements for human factors in ride quality, and (4) possible criteria for human factor in ride quality.
    Keywords: AIRCRAFT
    Type: Symp. on Vehicle Ride Quality; p 1-22
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  • 27
    Publication Date: 2006-04-26
    Description: A test program was undertaken to determine airline passenger reaction to vibration environments that might be encountered in a supersonic transport or other large commercial jet aircraft. The principal problem addressed was to determine accelerations of vertical and lateral vibration that people find objectionable. Further questions experimentally posed were: (1) what is the relationship between human reactions to vertical and lateral vibration, (2) to single- and combined-frequency vibration, and (3) to single- and combined-axis vibration? Interest was confined to reactions to vibration in the frequency range of 0.20 to 7.0 Hz, a range typical of the vibration environment of a large airplane. Results indicated an increasing sensitivity to vertical vibration as frequency was increased from 1.0 to 7.0 Hz. Subjects were found most sensitive to lateral vibration in the 1.0 to 3.0 Hz range. There was a nearly linear decrease in sensitivity as frequency of lateral vibration was increased from 3.0 to 7.0 Hz.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Symp. on Vehicle Ride Quality; p 91-113
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  • 28
    Publication Date: 2006-04-26
    Description: A flight test program to determine the effects of low frequency vibrations on passengers in short haul aircraft is discussed. The objective of the program is to accumulate flight test data on aircraft ride quality in terms of vehicle motion and acceleration and human responses. The subjects discussed are: (1) test procedures, (2) data processing, and (3) the program schedule.
    Keywords: AIRCRAFT
    Type: Symp. on Vehicle Ride Quality; p 247-251
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  • 29
    Publication Date: 2006-04-26
    Description: The approach of an aircraft manufacturer to ride quality in air transportation is presented. The subjects discussed are: (1) the external and internal environment in terms of vibration and acoustic sources and general response, (2) guidelines and criteria reflecting current practice, (3) present and future efforts to develop rideability criteria, and (4) requirements for data, criteria, and research in various rideability areas.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Symp. on Vehicle Ride Quality; p 23-49
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  • 30
    Publication Date: 2006-03-27
    Description: Noise tests of externally blown flaps with the engine under the wing and engine over the wing configurations were conducted. Flap noise data obtained on a TF-34 aircraft are discussed. Noise data obtained during a free-jet forward-speed-effect analysis are presented. Noise sources associated with upper surface flap blowing are described. Results of a small scale configuration screening study and some large scale model test data are analyzed. The noise data for the engine over wing configurations are compared with the engine under the wing configurations.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 455-473
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  • 31
    Publication Date: 2006-03-27
    Description: The characteristics of aerodynamic noise generated by the interaction of an airstream with a flap surface are discussed. The location and behavior of various noise sources were investigated to determine optimal quieting techniques. A schematic diagram of the jet-flap concepts being considered for integrated-powered-lift systems for short takeoff aircraft is shown. Each of the concepts has in common high velocity turbulent air flowing over relatively rigid surfaces with resultant production of interaction noise. The nature, location, and control of noise sources which involve the interactions of air flows with airfoil surfaces are examined.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 413-426
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  • 32
    Publication Date: 2006-03-27
    Description: Wind-tunnel investigations of the acoustic characteristics of the externally blown jet flap (EBF) and augmentor wing STOL concepts are discussed. The large-scale EBF model was equipped with a triple-slotted flap blown by four JT15D turbofan engines with circular, coannular exhaust nozzles. The large-scale augmentor wing model was equipped with an unlined augmentor blown by a slot primary nozzle. The effects of airspeed and angle of attack on the acoustics of the EBF were small. Flap deflection had a greater effect on the acoustics of the augmentor wing than did airspeed. The total sound power was also significantly higher for landing indicating that turning in the augmentor generated acoustic energy. Airspeed produced a small aft shift in acoustic directivity with no significant change in the peak perceived noise levels or sound power levels. Small-scale research of the acoustics for the augmentor wing has shown that by blowing an acoustically treated augmentor with a lobed primary nozzle, the 95-PNdb noise level goal can be achieved or surpassed.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 443-454
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  • 33
    Publication Date: 2006-03-27
    Description: Tests of the noise produced by the impingement of the jet exhaust on the wing and flap for an externally blown flap system were conducted with a CF700 turbofan engine and an F-111B wing panel. The noise produced with a daisy nozzle installed on the engine was greater than that produced by a conical nozzle at the same thrust. The presence of the wing next to the test nozzles increased the noise, as did increasing the flap deflection angle. Compared with the conical nozzle, the daisy nozzle produced slightly less noise at a flap deflection of 60 deg but produced more noise at the lower flap deflections tested. Tests showed that the single-slotted flap deflected 60 deg, produced less noise than the double-slotted flaps. Also, maintaining the maximum distance between the exit nozzle and flap system resulted in a minor reduction in noise.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 427-441
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  • 34
    Publication Date: 2006-03-27
    Description: A program plan to develop criteria for airworthiness standards for STOL transport aircraft is presented. Initially, three different STOL concepts are to be examined with a goal to arrive at a generalized set of standards. The Breguet 941 deflected-slipstream STOL has been initially evaluated on a piloted motion simulator and in flight. Confidence in establishing criteria for airworthiness standards for STOL transport aircraft has been obtained from these studies.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 345-351
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  • 35
    Publication Date: 2006-03-27
    Description: The Augmentor-Wing Jet STOL Research Aircraft has been developed and has started flight tests. The objectives of the program are to compare aerodynamic characteristics predicted from wind-tunnel data with data obtained in flight, to determine flight dynamic characteristics and limitations of the augmentor-wing concepts, and to contribute to the development of STOL design and operational criteria. Initial flight test results have shown that the aerodynamic characteristics are close to values predicted from wind-tunnel tests. The lateral-directional stability and control characteristics are satisfactory for research STOL missions with stability augmentation, but the longitudinal control require improvement. STOL take-off distance over 11 m is about 290 m, and landing approach speeds are between 60 and 65 knots. The investigation of the STOL operational and performance characteristics is continuing.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 259-282
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  • 36
    Publication Date: 2006-03-27
    Description: The considerations involved in making a piloted simulator an effective research tool in the design and development of new aircraft are discussed. An assessment of the limitations of the simulator in depicting real flight as well as the problem of recognizing erroneous results when the simulator is supplied with incorrect input data is made. Examples of the ways in which the simulator is used to design and develop the augmentor-wing aircraft are presented. Four areas of investigation are: (1) to design the lateral control system for proper feel and response, (2) determine the effect of engine failure during approach, (3) develop the best technique for controlling flight path during approach, and (4) the significance of lift loss in ground effect and how to compensate for such loss.
    Keywords: AIRCRAFT
    Type: Stol Technol.; p 283-290
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  • 37
    Publication Date: 2006-03-27
    Description: A STOL ride-control development program has been initiated with the objective of generating ride-control technology through development and evaluation of an active control system specifically designed to provide ride smoothing on a STOL vehicle. Although much can be learned through analysis, there are deficiencies in technology for translating analysis results into operating hardware. The general approach being followed is to select an existing STOL vehicle for trial and then carry out a study to establish feasibility of a control system or systems to smooth the ride and generate system trade-off data.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 215-226
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  • 38
    Publication Date: 2006-03-27
    Description: The development of STOL technology for application to operational short-haul aircraft is accompanied by the requirement for solving problems in many areas. One of the most obvious problems is STOL aircraft operations in the terminal area. The increased number of terminal operations needed for an economically viable STOL system as compared with the current CTOL system and the incompatibility of STOL and CTOL aircraft speeds are positive indicators of an imminent problem. The high cost of aircraft operations, noise pollution, and poor short-haul service are areas that need improvement. A potential solution to some of the operational problems lies in the capability of making curved landing approaches under both visual and instrument flight conditions.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 245-258
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  • 39
    Publication Date: 2006-03-27
    Description: Analytical investigations and piloted moving base simulator evaluations were conducted for manual control of flight path and airspeed for the approach and landing of a powered lift jet STOL aircraft. Flight-path and airspeed response characteristics were described analytically and were evaluated for the simulation experiments which were carried out on a large motion simulator. The response characteristics were selected and evaluated for a specified path and speed control technique. These characteristics were the initial flight-path response, flight-path overshoot, flight-path-airspeed coupling in response to a change in thrust, and the sensitivity of airspeed to pitch-attitude changes. Results are presented in the form of pilot opinion ratings and commentary, substantiated where appropriate by response time histories and aircraft states at the point of touchdown.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 181-198
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  • 40
    Publication Date: 2006-03-27
    Description: Data from wind-tunnel measurements are presented to show the magnitude of adverse ground effects on the longitudinal aerodynamic coefficients of a powered-lift STOL airplane. A steady-state analysis shows the changes in thrust and angle of attack required during the landing approach and flare as the airplane flies close to the ground. The piloting problems that these ground effects may create were investigated with an in-flight simulator to find the consequences of lift loss during the landing-flare maneuver for a STOL transport. Flight tests were made using the variable stability Navion setup with STOL transport aerodynamics and control responses and were flown at design approach speeds and descent conditions.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 199-213
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  • 41
    Publication Date: 2006-03-27
    Description: Full-scale ground tests of an externally blown flap system were made using the wing of an F-111B airplane and a CF700 engine. Pressure and temperature distributions were determined on the undersurface of the wing, vane, and flap for two engine exhaust nozzles (conical and daisy) at several engine power and engine/wing positions. The tests were made with no airflow over the wing. The leading-edge wing sweep angle was fixed at 26 deg, the angle of incidence between the engine and the wing was fixed at 3 deg, and the tests were conducted with the flap retracted, extended and deflected 35 deg, and extended and deflected 60 deg. The integrated local pressures on the undersurface of the flap produced loads approximately three times as great at the 60 deg flap position as at the 35 deg flap position. With both nozzle configurations, more than 90 percent of the integrated pressure loads were contained within plus or minus 20 percent of the flap span centered around the engine exhaust centerline. The maximum temperature recorded on the flaps was 218 C (424 F) for the conical nozzle and 180 C (356 F) for the daisy nozzle.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 143-156
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  • 42
    Publication Date: 2006-03-27
    Description: Concurrent simulations of powered-lift STOL transport aircraft having either an externally blown flap configuration or an augmentor wing configuration were conducted. The following types of simulators of varying sophistication were used: (1) a simple fixed-base simulation with a simple visual display, (2) a more complex fixed-base simulation using a realistic transport cockpit and a high-quality visual display, and (3) a six-degree-of-freedom motion simulator that had a realistic transport cockpit and a sophisticated visual display. The unaugmented flying qualities determined from these simulations were rated as unacceptable for both the externally blown flap and augmentor wing configurations. The longitudinal, lateral-directional, and single-engine-failure characteristics were rated satisfactory with extensive augmentation, including pitch and roll command systems, flight-path (or speed) augmentation, turn coordination, and effective yaw damping. However, the flare and landing characteristics from any approach glide-path angle in excess of 4 deg were rated as unsatisfactory but acceptable.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 157-800
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  • 43
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    In:  CASI
    Publication Date: 2006-03-27
    Description: The results of some preliminary wind-tunnel investigations made to provide fundamental aerodynamic information on the upper surface blown jet-flap concept incorporating high-bypass-ratio turbofan engines are summarized. The results of the investigation have shown the concept to have aerodynamic performance generally similar to that of other externally blown high-lift systems. A few of the more critical problems associated with this concept have been identified and preliminary solutions to some of these problems have been found. These results have proven to be sufficiently encouraging to warrant continuation of fundamental research efforts on the concept.
    Keywords: AERODYNAMICS
    Type: NASA. Langley Res. Center STOL Technol.; p 97-110
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  • 44
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    In:  CASI
    Publication Date: 2006-03-27
    Description: Results of research on advanced augmentors are discussed. Research concerned with performance has indicated that: (1) augmentors with lobe-type nozzles give higher thrust augmentation than those with slot-type primary nozzles, (2) the thrust of augmentor wings at forward speed is greater than that of internally blown flaps for the speed range of interest, and (3) the optimum augmentor geometry at forward speed may be different from the optimum static geometry. Analysis of augmentor-wing data has shown that the data may be correlated by accounting for the augmentation and entrainment in defining a net thrust coefficient.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 87-96
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  • 45
    Publication Date: 2006-03-27
    Description: A brief outline of augmentor wing research sponsored by Ames Research Center is presented and is followed by a discussion of large-scale wind-tunnel test results for a swept augmentor wing configuration. The results showed that the augmentor wing could be applied to high-speed swept wing designs with little adverse effect on either the basic performance of the augmentor or the longitudinal characteristics, including maximum lift and stall. Three lateral control devices were shown to be effective and ground effect was measured for several complete aircraft configurations.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 71-86
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  • 46
    Publication Date: 2006-03-27
    Description: Small-scale-model data have shown large static loads on the flap system behind the engines. The large-scale-model tests confirmed the magnitude of these loads and indicated that the relative loading of each flap element depends on the engine-wing-flap geometry. Flap response measurements indicated that the unsteady pressure loading excited the natural vibration modes of the flap system on this model. Since this was a boilerplate model, the only conclusion that can be drawn is that the possibility of large vibration loads must be considered for a flight-weight structure. The similarity of the unsteady pressure and flap response spectra for the wind-off and wind-on cases indicated that it may be possible to realistically test flight-weight flap structures on a static test stand rather than endure the extra costs and scheduling problems associated with large-scale wind-tunnel tests. There is a potential flap-temperature problem which if not resolved might preclude the use of materials such as aluminum and the composites in the flap structure.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 121-130
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  • 47
    Publication Date: 2006-03-27
    Description: The application of externally blown flaps for improving the performance of short takeoff aircraft is discussed. The characteristics of externally blown flap powered lift are examined. A method for predicting the aerodynamic performance of a particular externally blown flap configuration is presented. The following specific effects are analyzed: (1) induced aerodynamics, (2) static turning, (3) flap span and deflection, and (4) engine size and chord flap.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 43-54
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  • 48
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    In:  CASI
    Publication Date: 2006-03-27
    Description: Short takeoff aircraft technology development related to the requirements for an expanded and improved short-haul air transportation system is discussed. Systems requirements are summarized, principal aircraft requirements are identified, the status of STOL technology is analyzed, and the scope of the technology efforts covered by the conference are outlined. Charts and diagrams are provided to explain system requirements, lift capability trends, and terminal airspace requirements.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 35-42
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  • 49
    Publication Date: 2006-03-27
    Description: The results of wind-tunnel investigations on the stability and control characteristics of externally blown jet-flap configurations are presented. Conventional wind-tunnel tests and free-flight model tests have shown that longitudinal trim and stability can be achieved by a properly located horizontal tail of sufficient size, and that lateral trim in the engine-out condition can be produced by combinations of differential flap, spoiler, and rudder deflection. Free-flight model tests have revealed a lightly damped Dutch roll lateral oscillation, and have shown that the oscillation can be stabilized by use of artificial damping.
    Keywords: AERODYNAMICS
    Type: STOL Technol.; p 55-70
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  • 50
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    In:  CASI
    Publication Date: 2006-03-27
    Description: The application of short takeoff and landing aircraft for improving short-haul air transportation is examined. The contracts with industry to study quiet turbofan short-field aircraft in the short-haul air transportation system are identified. Studies of appropriate propulsion systems are conducted in parallel with the aircraft studies. The objectives of the studies are to: (1) determine economic and social viability of short-haul air transportation, (2) identify critical technology and technology-related problems, (3) define representative aircraft configurations and characteristics to include development and operational costs, and (4) to establish desirable technology advances for improving short-haul transportation systems.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 9-22
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  • 51
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    In:  CASI
    Publication Date: 2006-03-27
    Description: The requirements for short-haul air transportation services in the 1980 time period are analyzed. The identification of short takeoff and landing aircraft to perform this service is reviewed. The adequacy of technical programs for developing short-haul aircraft is examined. The characteristics of several candidate short-haul aircraft are described. A system analysis, to include the economic and environmental factors, is developed.
    Keywords: AIRCRAFT
    Type: STOL Technol.; p 1-8
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  • 52
    Publication Date: 2011-08-16
    Description: The problems and potential of V/STOL transportation are examined. A detailed review is given of the development, characteristics, and requirements of V/STOL, STOL, and VTOL systems. The problem of whether V/STOL is worth the effort is considered, and it is concluded that such aircraft have a role in meeting real transport requirements, and that their development should be pursued. Finally, a forecast of V/STOL economics is presented, and implementation problems are discussed.
    Keywords: AIRCRAFT
    Type: Technology Review; 74; May 1972
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  • 53
    Publication Date: 2011-08-16
    Description: The wave interference effects for bodies or wings in a mirror-symmetric arrangement, and in an antisymmetric arrangement are discussed. It is shown that while in the case of a mirror-symmetric arrangement large adverse interference effects can be observed, antisymmetric arrangements provide comparatively much smaller wave drags. The single continuous wing panels also adapt themselves more readily to varying angles of obliquity, and hence, to varying flight speeds. A detailed review is presented of the previous work on the aerodynamic properties and flight stability of oblique elliptic wing combinations. A possible mode of application of these combinations to transport aircraft operating at moderate supersonic speeds is suggested.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Feb. 197
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  • 54
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    Publication Date: 2011-08-16
    Description: Noise and congestion present the two main technological constraints on air-transportation growth. Although some of the noise reduction will come with improved flight-path control and steep approaches, the main requirement remains quiet propulsion systems. Higher engine temperatures will compensate for efficiency losses due to noise suppression. Composite structures can reduce structural weight by 20%. New developments in rotorcraft transports are discussed together with advanced subsonic transports of the 1980s and the possibilities for further evolution of the SSTs, leading to a hypersonic aircraft.
    Keywords: AIRCRAFT
    Type: Astronautics and Aeronautics; 10; Jan. 197
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  • 55
    Publication Date: 2011-08-16
    Description: The experiment was performed on the test section sidewall in a supersonic pressure tunnel. The boundary layer at the test station was surveyed in turn by each of 8 impact probes ranging in size from about 1.3 to 48 mm. The impact pressures measured by these probes were combined with the test section static pressure to calculate Mach numbers. Probe displacement effects were evaluated in terms of these Mach number values.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Apr. 197
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  • 56
    Publication Date: 2011-08-16
    Description: Features of hypersonic, finite-span separated flows with a turbulent boundary layer have been studied to provide a partial assessment of transverse outflow effects on separated flowfield characteristics. Results demonstrate the critical importance of transverse outflow in determining some of the characteristic features of a turbulent, separated boundary layer.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Apr. 197
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  • 57
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    Publication Date: 2011-08-16
    Description: The dynamics of tracked air-cushion vehicles considered for high-speed ground transportation systems are examined using a vehicle model represented by a one-degree-of-freedom system. The respective equations of motion are derived, and the control system is discussed. The equations obtained for the cushion are solved using an analog computer. The computer showed the effect of the control technique on the relative motion between vehicle and guideway.
    Keywords: AIRCRAFT
    Type: Instruments and Control Systems; 45; Apr. 197
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  • 58
    Publication Date: 2011-08-16
    Description: A simple eddy-viscosity model is shown to make it possible to calculate numerically the mean properties of a turbulent wake. Although the structure of the Reynolds stress terms is not resolved, the results obtained are adequate for predicting velocity profiles and displacement thicknesses.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Feb. 197
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  • 59
    Publication Date: 2011-08-16
    Description: A review is given of information obtained in recent years concerning the effects on sonic-boom signatures of departures of the atmosphere from a perfectly stratified time invariant model. These effects include the observed random variations in boom overpressures from those expected for a stratified atmosphere, the anomalously large and variable rise times, and the occurrence of spiked or rounded waveforms rather than the characteristic N waves. The extent of the variability in data recorded during actual flight tests is summarized in the form of histograms, representing experimentally obtained probability density functions. The physical mechanisms believed to be responsible for the variations and the anomalous features in the signatures are described. These include refraction and subsequent wavefront rippling by turbulence, the possible focusing or defocusing of rays, the formation of caustics, and the phenomenon of wavefront folding, diffraction, and scattering. Recent statistical theories of shock propagation through a turbulent atmosphere proposed by Crow, George and Plotkin, Pierce, Horning, and others are reviewed.
    Keywords: AIRCRAFT
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  • 60
    Publication Date: 2011-08-16
    Description: The prediction techniques reviedi he present paper permit the calculation of sonic booms produced by rather complex conventional supersonic aircraft designs performing level nonaccelerated flight in a quiet atmosphere. Basic concepts of supersonic flow analysis, for representation of an airplane as a linear distribution of disturbances and for determination of the resultant pressure field complete with shocks, are outlined. Numerical techniques for implementation of the theory are discussed briefly, and examples of the correlation of theory with experimental data from wind tunnel and flight tests are presented. Special attention is given to presentation of a simplified method for rapid 'first-cut' estimation of farfield bow-shock overpressure. Finally, some problems encountered in attempts at applying the prediction techniques for the nearfield at high supersonic Mach numbers are recognized, and the need for further refinement of present techniques or the development of new systems is discussed.
    Keywords: AIRCRAFT
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  • 61
    Publication Date: 2011-08-16
    Description: The application of Rose's (1970) analytical method to the study of a shock wave interacting with a turbulent layer on a blunted compression surface is described. Only those details of the method that specifically apply to the case under consideration are discussed.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Apr. 197
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  • 62
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    Publication Date: 2011-08-16
    Description: Considerations are given to demonstrate that a wing which pivots as a whole would permit supersonic aircraft which avoid sonic boom and reduce noise around airports. Several such wing designs are discussed. Wind-tunnel tests results are given to support the soundness of this wing design.
    Keywords: AIRCRAFT
    Type: Astronautics and Aeronautics; 10; Dec. 197
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  • 63
    Publication Date: 2011-08-16
    Description: Direct skin friction measurements obtained on the wall of a Mach 19.8 nozzle are presented. These measurements of skin friction and values deduced from the profile data are compared with predictions from a finite difference theory and also with several 'flat-plate' prediction methods for skin friction.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Sept
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  • 64
    Publication Date: 2011-08-16
    Description: Investigation of the Taylor instability relative to the dynamical instability whose presence in the shock layer on a spacecraft entering the Jovian atmosphere is to be expected because of the difference in velocity across the shear layer. Presented calculations show that the Taylor instability at the interface between shock-heated freestream gas and ablation products is inconsequential in comparison to the shear layer instability.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Sept
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  • 65
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    Publication Date: 2011-08-16
    Description: The transition Reynolds number for shear layers produced by interactions between weak and strong shock waves is determined on the basis of experiments performed in a 20-in. (Mach 6) and an 11-in. (Mach 6.9) hypersonic tunnel. A variable angle wedge was used to generate a planar shock wave which interacted with the bow wave of a blunt body. An average value of the transition length (defined as the length along the shear layer from the shock interaction to the point where turbulence became visible on schlieren photographs) was used to determine the transition Reynolds number.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Aug. 197
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  • 66
    Publication Date: 2011-08-16
    Description: Correlations are given of measured pressure and heat-transfer peaks for shock/boundary-layer interactions and shear layer attachment on configurations with both two- and three-dimensional interactions. The peak values were obtained from an investigation of shock interference heating on hemispheres, a 30-deg included angle wedge, and a 2.54-cm-diam cylindrical leading-edge fin model. The investigation covers data for Mach numbers of 6 and 20 over freestream Reynolds numbers ranging from (3.3 to 25.6) million per meter, and specific heat ratios of 1.4 and 1.67.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Aug. 197
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  • 67
    Publication Date: 2011-08-16
    Description: Boundary-layer transition on 5- and 15-deg half-angle cones was studied as a function of angle of attack (ranging from 0 to 20 deg) in a 3.5 ft hypersonic wind tunnel at a freestream Mach number of 7.4. It is shown that the influence of the angle of attack on the transition Reynolds number is a function of the meridian angle. On the windward ray of the 15-deg cone, transition Reynolds numbers show an initial slight increase and then a decrease with increasing angle of attack; leeward-ray Reynolds numbers for this cone decrease rapidly with angle of attack. Windward-ray transition Reynolds numbers increase monotonically with angle of attack on the 5-deg cone, but the effect of the angle of attack on the leeward ray is the same as for the 15-deg cone.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Aug. 197
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  • 68
    Publication Date: 2011-08-16
    Description: The results of Murman and Krupp (1971) are used to develop a procedure for computing a transonic flow about a finite lifting wing. A small disturbance equation describing the velocity potential of three-dimensional wings is solved in the process. The procedure is applied to a wing with a symmetric biconvex airfoil section in a zero-incidence subsonic flow, to a supersonic rectangular lifting wing with a sharp leading edge and to a subcritical nonlifting rectangular wing with a blunt leading edge.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; July 197
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  • 69
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    Publication Date: 2011-08-16
    Description: Review of the overall goals, individual objects of ongoing and proposed programs, target dates, and fund requests of NASA's STOL research effort. The realization of a separate STOL short-haul transportation system with a 2000-foot field length capability is shown likely to reduce airport acreage requirements to less than one tenth, approach speed to nearly one half, and airspace required for terminal maneuvering to less than 10% of what conventional high-performance jet aircraft necessitate, and to promise terminal congestion alleviation in areas of high traffic density, improved safety in steep approach, noise abatement, and community annoyance reduction. NASA's described programs will provide the technical foundation upon which industry can base the design and development of aircraft and avionics for the new STOL systems in the latter 1970s, and upon which the government can establish criteria for the certification and regulation of such systems.
    Keywords: AIRCRAFT
    Type: Airport Forum; June 197
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  • 70
    Publication Date: 2011-08-16
    Description: The inverse technique is used to obtain a mathematically and physically consistent solution of the flowfield in a nozzle from the mass generation surface through the supersonic region. The inverse method employs an assumed centerline function which is of the Cauchy type in that the values and the derivatives of the function are known. Since the Cauchy boundary conditions can give rise to numerical instabilities, the governing gasdynamic equations for rotational steady flow were transformed into a form which puts the geometry into a rectangular shape, and which spaces the network of interior points more finely in regions of the greatest gradients of the dependent variables. For arbitrarily specified centerline data, the solution of the governing flow equations may not exist, and if it does it may not depend continuously on the data.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; June 197
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  • 71
    Publication Date: 2011-08-16
    Description: Wall static pressure measurements and performance parameters are presented for axisymmetric supersonic nozzles with relatively steep convergent sections and comparatively small radius-of-curvature throats. The nozzle walls were essentially adiabatic. These results are compared with those obtained in other nozzles tested previously to appraise the influence of contraction shape on performance. Both the flow coefficient and the thrust were less than the corresponding values for one-dimensional, isentropic, plane flow for both the axial and radial inflow nozzles considered, but the specific impulse, the most important performance parameter, was found to be relatively unchanged. The thrust decrement for the axial inflow nozzles was established primarily by the shape of the contraction section, and could be estimated reasonably well from a conical sink flow consideration. The radial inflow nozzle has a potential advantage from a cooling point of view if used in a rocket engine.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; June 197
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  • 72
    Publication Date: 2011-08-16
    Description: Experimental results suggest that the boundary-layer mean profiles in hypersonic flows may be highly transitional in the outer part of the boundary layer before the transition process is detected at the surface. Means of determining the initial location where the transition process begins in the outer part of the boundary layer are considered.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; May 1972
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  • 73
    Publication Date: 2011-08-16
    Description: A first-order theory of the fluctuating lift and drag coefficients associated with the aerodynamically induced motions of rising and falling spherical wind sensors is developed. The equations of motion of a sensor are perturbed about an equilibrium state in which the buoyancy force balances the mean vertical drag force. It is shown that, to within first order in perturbation quantities, the aerodynamic lift force is confined to the horizontal, and the fluctuating drag force associated with fluctuations in the drag coefficient acts along the vertical. The perturbation equations are transformed with Fourier-Stieltjes integrals. The resulting equations lead to relationships between the power spectra of the aerodynamically induced velocity components and the spectra of the fluctuating lift and drag coefficients.
    Keywords: AERODYNAMICS
    Type: Journal of Applied Meteorology; 11; Apr. 197
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  • 74
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    Publication Date: 2011-08-16
    Description: Review of oblique water and fluorocarbon injection test results obtained in experimental studies of the effects of multiple-orifice liquid injection into hypersonic air streams. The results include the finding that maximum lateral penetration from such injections increases linearly with the square root of the jet-to-freestream dynamic-pressure ratio and is proportional to an equivalent orifice diameter.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Dec. 197
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  • 75
    Publication Date: 2011-08-16
    Description: This paper is the second of two companion papers. In the first paper, expressions for the acoustic field generated inside a room with an open window due to incoming transient or periodic signals have been presented. In this paper, the technique has been applied to the specific example of an N-wave type signal. Detailed mathematical analysis is followed by its approximate version and numerical computation. Results of controlled experiments, using simulated sonic booms, have been compared with theoretical predictions.
    Keywords: AIRCRAFT
    Type: Journal of Sound and Vibration; 25; Dec. 22
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  • 76
    Publication Date: 2011-08-16
    Description: A fluid-dynamic investigation was carried out to determine the cause of intense heating observed on the lee meridian of hypersonic delta wings and also to derive means for its suppression. Several experimental techniques were combined with analysis of extensive heat-transfer measurements at a freestream Mach number of six in a range of Reynolds number to acquire a general description of the lee-flow structure. With attached leading-edge flow on the delta wings, the dominant feature is a pair of embedded vortices on the lee meridian whose interaction with the boundary-layer is responsible for the observed local heating. On the basis of flow visualization results and heat-transfer correlations, a qualitative vortex flow model is proposed which differs essentially from the conventional inboard separation vortex model.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Nov. 197
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  • 77
    Publication Date: 2011-08-16
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 9; Oct. 197
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  • 78
    Publication Date: 2011-08-16
    Description: This paper describes the application of linear stochastic optimal control theory to the design of the control system for the air intake, the inlet, of a supersonic air-breathing propulsion system. The controls must maintain a stable inlet shock position in the presence of random airflow disturbances and prevent inlet unstart. Two different linear time invariant controllers are developed. One is designed to minimize a nonquadratic index, the expected frequency of inlet unstart, and the other is designed to minimize the mean square value of inlet shock motion. The quadratic equivalence principle is used to obtain a linear controller that minimizes the nonquadratic index. The two controllers are compared on the basis of unstart prevention, control effort requirements, and frequency response. It is concluded that while controls designed to minimize unstarts are desirable in that the index minimized is physically meaningful, computation time required is longer than for the minimum mean square shock position approach. The simpler minimum mean square shock position solution produced expected unstart frequency values which were not significantly larger than those of the nonquadratic solution.
    Keywords: AIRCRAFT
    Type: Automatica; 8; Sept
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  • 79
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    Publication Date: 2011-08-16
    Description: Analysis of the response of rising spherical balloons to a constant wind shear condition. Wind shear tends to produce a terminal rise rate that is less than the terminal rise rate in the absence of wind shear by no more than 1% of the wind shear and a horizontal balloon velocity defect relative to the local wind with magnitude less than or about equal to 0.2 of the wind shear for most meteorological balloons. An analysis of the behavior of a balloon in a wind field in which the wind shear varies along the vertical is also presented.
    Keywords: AIRCRAFT
    Type: Journal of Geophysical Research; 77; July 20
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  • 80
    Publication Date: 2011-08-16
    Description: Detailed experimental measurements of the characteristics and level of pre- and postshock disturbances obtained for typical disturbance modes and shock angles are presented to aid in the evaluation of transition studies conducted in 'noisy' hypersonic wind tunnels. The presented data suggest that the shock is probably generating total temperature fluctuations in a fashion directly related to shock strength. Since in high supersonic and hypersonic flows the total temperature fluctuations are mainly contained in velocity fluctuations, it may be concluded that the predominant disturbances generated are vorticity as long as the postshock flow is at a sufficiently high Mach number.-
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Dec. 197
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  • 81
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    Publication Date: 2011-08-16
    Description: Review of data obtained on turbulent burst geometry and growth characteristics for cone boundary-layer transition in a helium wind tunnel at a boundary-layer edge Mach number (Me) of 7.6. Detailed data concerning turbulent spot geometry and downstream propagation velocities were obtained using a spark schlieren system with sequential spark capability. In one particular test evidence of a symmetrical turbulent burst ring was obtained; all other bursts developed in a singular random manner. Profiles of the apparent outer edges of the bursts were obtained, and the velocities of the leading and trailing edges of the bursts relative to the local velocity were determined. The velocities of the leading and trailing edges were found to be fairly consistent for each observation, with the leading edge of the burst traveling at about local edge velocity, while the trailing edge moved supersonically relative to local speed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Oct. 197
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  • 82
    Publication Date: 2011-08-16
    Description: Determination of the stagnation region heating of probes entering the Venusian atmosphere. Both convective and radiative heat-transfer rates are predicted, and account is taken of the important effects of radiative transport in the vehicle shock layer. A nongray radiative transport model is utilized which parallels a four-band treatment previously developed for air (Page et al., 1969), but includes two additional bands to account for the important CO(4+) molecular band system. Some comparisons are made between results for Venus entry and results for earth entry obtained using a viscous earth entry program.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Oct. 197
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  • 83
    Publication Date: 2011-08-16
    Description: The objective of the work described in this and the companion paper was to establish a theory for predicting the sound field generated in a room by a sonic boom incident on an open window. In this paper, some basic theoretical results are presented. First, the case of a normally incident harmonic wave was considered. Expressions for the pressure field were obtained by viewing the room as a terminated duct and by using a Green function method. The concept of mode excitation distribution functions was formulated and used to match the boundary conditions. This concept has been extended for oblique incidence. A modified form of Laplace transform technique was used to obtain expressions in the time domain for transient signals.
    Keywords: AIRCRAFT
    Type: Journal of Sound and Vibration; 25; Dec. 22
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  • 84
    Publication Date: 2011-08-16
    Description: A procedure is given for deriving the equations describing the surface streamline metric in a general form and in a form suitable for incorporation into computer codes to calculate an inviscid flow about three-dimensional bodies. Sample results are included to show the application of the metric in conjunction with an axisymmetric analog to predict heat transfer to a typical space shuttle orbiter.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 10; Nov. 197
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  • 85
    Publication Date: 2011-08-16
    Description: Data were obtained concerning a model which utilized a two-dimensional sonic jet. It was found that outflow and jet location significantly influence the magnitude and behavior of the secondary jet interaction forces. Continued refinements in jet interaction analyses which do not account for outflow are of limited usefulness in the design of control systems for supersonic and hypersonic vehicles. The jet total back pressure ratio increases with either jet pressure ratio or freestream Mach number.
    Keywords: AERODYNAMICS
    Type: Journal of Spacecraft and Rockets; 9; Nov. 197
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  • 86
    Publication Date: 2011-08-16
    Description: An assessment is made of recent repeated loads data from short-haul jet transports and several general aviation airplanes. The jet transport data indicate that except for check flight maneuvers the load histories are essentially independent of operator and airplane type. General aviation data show a large amount of scatter in the repeated load history. The use and geographical location of operations may be the primary means of specifying the repeated loads environment.
    Keywords: AIRCRAFT
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  • 87
    Publication Date: 2012-05-23
    Description: An automatic method for determining stability and control derivatives from flight data is presented. The technique, a modification of the Newton-Raphsom method for derivative extraction, has a priori provision that makes use of initial estimates of the derivatives and provides a means of checking the validity of the results. Recommendations for applications of the method are included.
    Keywords: AIRCRAFT
    Type: AGARD Stability and Control te]; 13 p
    Format: text
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  • 88
    Publication Date: 2012-05-23
    Description: Conceptual and wind-tunnel programs leading to the development of technology for applying active controls to the suppression of flutter were studied to provide a powerful tool for required safety margins for flutter in future high-performance supersonic aircraft. The nature of flutter considerations in the design of the U.S. SST prototype aircraft is described as an example of the type of application where active flutter suppression shows promise.
    Keywords: AIRCRAFT
    Type: AGARD Stability and Control te]; 8 p
    Format: text
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  • 89
    Publication Date: 2012-05-23
    Description: Revisions which have been made to previous V/STOL handling qualities requirments based on criteria are discussed. A discussion of the pilot's desire for a particular characteristic is given. In addition, data and reference material are provided to back up the proposed criteria to permit the user to understand the limitations of the data on which the criteria are based. A review is included of several controversial areas including pitch control sensitivity, static longitudinal stability, roll control power, roll-yaw cross coupling, and vertical flight path control.
    Keywords: AIRCRAFT
    Type: AGARD Stability and Control te]; 10 p
    Format: text
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  • 90
    Publication Date: 2012-05-23
    Description: The high subsonic and transonic characteristics of fighter aircraft and the factors affecting aerodynamic boundaries, such as maximum obtainable lift, buffet onset, pitchup, wing rock, and nose slice are discussed. Investigations were made using a general research configuration which encompassed a systematic matrix of wing design parameters. These results emphasized the sensitivity to section and planform geometry at the selected design point. The incorporation of variable-wing-geometry devices in the form of leading-edge slats or flaps was shown in a number of flight and wind-tunnel studies to provide controlled flow over a wide range of flight conditions and substantial improvements in maneuver capabilities. Additional studies indicated that the blending of a highly swept maneuver strake with an efficient moderately swept wing offers a promising approach for improving maneuver characteristics at high angles of attack without excessive penalties in structural weight.
    Keywords: AIRCRAFT
    Type: AGARD Fluid Dyn. of Aircraft Stalling; 11 p
    Format: text
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  • 91
    Publication Date: 2012-05-23
    Description: A brief review of selected handling qualities criteria for V/STOL aircraft shows that although a clearer understanding of the requirements for controversial areas such as roll control power, vertical flight path control, and transition is in hand, considerably more research is needed to refine these criteria for operational IFR activity. Because many items interact to influence the pilots' overall impression of the aircraft's behaviour, additional work of a systematic nature must be done to clarify this aspect. A better definition of a gust model which includes discrete gust effects is needed to firm up criteria for both hover and STOL operation.
    Keywords: AIRCRAFT
    Type: AGARD Handling Qualities Criteria; 8 p
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  • 92
    Publication Date: 2016-06-07
    Description: The design parameters which determine cruise performance for a conventional subsonic jet transport are discussed. It is assumed that the aircraft burns climb fuel to reach cruising altitude and that aeronautical technology determines the ability to carry a given payload at cruising altitude. It is shown that different sizes of transport aircraft are needed to provide the cost optimal vehicle for different given payload-range objectives.
    Keywords: AIRCRAFT
    Type: Proc. of the NASA(MIT Workshop on Airline Systems Analysis, Vol. 1; 50 p
    Format: application/pdf
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  • 93
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2016-06-07
    Description: In the investigation of the failure of one of the three main parachutes of the Apollo 15 spacecraft, which collapsed at approximately 1825 meters after operating properly from deployment at 3050 meters, three conditions considered to be possible causes of the failure were produced. The suspect conditions were the proximity of the forward heat shield that passed the spacecraft at approximately 1825 meters, the dumping of the reaction control system hypergolic propellants at approximately 1825 meters, and the failing of a riser link found on a recovered parachute. (The failed parachute was not recovered). The remaining two parachutes functioned as planned and averted a catastrophic failure. The conclusions concerning the cause of the failure are discussed.
    Keywords: AIRCRAFT
    Type: The 7th Aerospace Mech. Symp.; p 137-148
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  • 94
    Publication Date: 2016-06-07
    Description: The statistical analysis of flight times as well as airplane gross weights and fuel weights of jet-powered civil transport airplanes has shown that the distributions of their frequency of occurrence per flight can be presented approximately in general form. Before, however, these results may be used during the project stage of an airplane for defining a typical mission profile (the parameters of which are assumed to occur, for example, with a probability of 50 percent), the following points have to be taken into account. Because the individual airplanes were rotated during service, the scatter between the distributions of mission profile parameters for airplanes of the same type, which were flown with similar payload, has proven to be very small. Significant deviations from the generalized distributions may occur if an operator uses one airplane preferably on one or two specific routes. Another reason for larger deviations could be that the maintenance services of the operators of the observed airplanes are not representative of other airlines. Although there are indications that this is unlikely, similar information should be obtained from other operators. Such information would improve the reliability of the data.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Advanced Approaches to Fatigue Evaluation; p 541-563
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  • 95
    Publication Date: 2016-06-07
    Description: A review of records maintained by the National Transportation Safety Board showed that 16,054 civil aviation accidents occurred in the United States during the 3-year period ending December 31, 1969. Material failure was an important factor in the cause of 942 of these accidents. Fatigue was identified as the mode of the material failures associated with the cause of 155 accidents and in many other accidents the records indicated that fatigue failures might have been involved. There were 27 fatal accidents and 157 fatalities in accidents in which fatigue failures of metal components were definitely identified. Fatigue failures associated with accidents occurred most frequently in landing-gear components, followed in order by powerplant, propeller, and structural components in fixed-wing aircraft and tail-rotor and main-rotor components in rotorcraft. In a study of 230 laboratory reports on failed components associated with the cause of accidents, fatigue was identified as the mode of failure in more than 60 percent of the failed components. The most frequently identified cause of fatigue, as well as most other types of material failures, was improper maintenance (including inadequate inspection). Fabrication defects, design deficiencies, defective material, and abnormal service damage also caused many fatigue failures. Four case histories of major accidents are included in the paper as illustrations of some of the factors invovled in fatigue failures of aircraft components.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Advanced Approaches to Fatigue Evaluation; p 611-630
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  • 96
    Publication Date: 2016-06-07
    Description: Cost effectiveness airframe considerations dictated a variable geometry wing design that requires weight optimization, maximum working stress resistance and minimum fatigue concentration factors. The extensive use of titanium structural materials employed electron beam welding methods and interference fit fastening techniques as principle mechanical joining means for economic F-14A production and reliability engineering.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Proc. of the Symp. on Welding, Bonding, and Fastening; 20 p
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  • 97
    Publication Date: 2016-06-07
    Description: A brazed titanium honeycomb sandwich system for supersonic transport wing cover panels provides the most efficient structure spanwise, chordwise, and loadwise. Flutter testing shows that high wing stiffness is most efficient in a sandwich structure. This structure also provides good thermal insulation if liquid fuel is carried in direct contact with the wing structure in integral fuel tanks.
    Keywords: AIRCRAFT
    Type: NASA. Langley Res. Center Proc. of the Symp. on Welding, Bonding, and Fastening; 21 p
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  • 98
    Publication Date: 2018-10-19
    Description: A review of major ride-quality criteria used in the design of commercial helicopters, some of the limitations of these criteria, research programs conducted to better define these criteria, and some recommended research programs is presented. Primary emphasis is given to the question of noise and vibration criteria for passenger acceptance and comfort.
    Keywords: AIRCRAFT
    Type: NASA. Langley Research Center Symposium on Vehicle Ride Quality; 51-66
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  • 99
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-28
    Description: This volume contains cost, schedule, and technical information on the following B-70 aircraft subsystems: air induction system, flight control, personnel accommodation and escape, alighting and arresting, mission and traffic control, flight indication, test instrumentation, and installation, checkout, and pre-flight.
    Keywords: AERODYNAMICS
    Type: NASA-CR-115705 , SD-72-SH-0003-VOL-4 , NAS 1.26:115705 , JSC-CN-29834
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  • 100
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-28
    Description: Volume 2 of the final report on the B-70 aircraft study is presented here. The B-70 Program, at the onset, was a full weapon system capable of sustained Mach 3 flight for the major portion of its design missions. The weapon system was to enter the SAC inventory as an RS-70 with the first intercontinental resonnaissance/bomber wing scheduled to go operational in July, 1964. After several redirections, a two XB-70 air vehicle program emerged with its prime objective being to demonstrate the technical feasibility of sustained Mach 3 flight. This section describes the original Weapon System 110A concepts, the evolution of the RS-70 design, and the XB-70 air vehicles which demonstrated the design, fabrication, and technical feasibility of long range Mach 3 flights at high altitude. The data presented shows that a very large step forward in the state-of-the-art of manned aircraft design was achieved during the B-70 development program and that advances were made and incorporated in every area, including design, materials application, and manufacturing techniques.
    Keywords: AERODYNAMICS
    Type: NASA-CR-115703 , SD-72-SH-0003-VOL-2 , NAS 1.26:115703 , JSC-CN-29832
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