Double hinged flap Patent
Double hinged flap for boundary layer control over trailing edges of wings
Turner, T. R.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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High entrainment ejector design
High entrainment constant area multiple nozzle ejectors with two mixing tube lengths for boundary layer control, estimating performance with analytical model
Carey, J. H.↗
Ground effect for V/STOL aircraft configurations and its simulation in the wind tunnel. Part 2: Experimental studies
Wind tunnel tests on a finite, knee-blowing-flapped wing and on a direct jet lift configuration were performed in a 30 x 42 inch wind tunnel. The objectives of these tests were, in experimental order:(1) to obtain definitive fixed-versus-moving ground comparisons on a powered, high-lift finite wing and on a lifting jet configuration as a function of model height and lift, (2) to understand the flow mechanism which lead to observed differences between moving and fixed-ground results, (3) to discover whether the above effects of a moving ground plane can be simulated by tangential-blowing boundary layer control at the wind tunnel floor, and (4) to check the form and the numerical constants for the wall jet blowing equation derived theoretically in Part I of this report. This relates wall jet blowing quantities to model lift coefficient.
Hackett, J. E.↗
Small, high pressure ratio compressor: Aerodynamic and mechanical design
The Small, High-Pressure-Ratio Compressor Program was directed toward the analysis, design, and fabrication of a centrifugal compressor providing a 6:1 pressure ratio and an airflow rate of 2.0 pounds per second. The program consists of preliminary design, detailed areodynamic design, mechanical design, and mechanical acceptance tests. The preliminary design evaluate radial- and backward-curved blades, tandem bladed impellers, impeller-and diffuser-passage boundary-layer control, and vane, pipe, and multiple-stage diffusers. Based on this evaluation, a configuration was selected for detailed aerodynamic and mechanical design. Mechanical acceptance test was performed to demonstrate that mechanical design objectives of the research package were met.
Bryce, C. A.↗
Some design considerations for supersonic cruise mixed compression inlets
A mixed compression inlet designed for supersonic cruise has very demanding requirements for high total pressure recovery and low bleed and cowl drag. However, since the optimum inlet for supersonic cruise performance may have other undesirable characteristics, it is necessary to establish trade-offs between inlet performance and other inlet characteristics. Some of these trade-offs between the amount of internal compression, aerodynamic performance and angle-of-attack tolerance are reviewed. Techniques for analysis of boundary layer control and subsonic diffuser flow are discussed.
Bowditch, D. N.↗
Some design considerations for supersonic cruise mixed compression inlets
A mixed compression inlet designed for supersonic cruise has very demanding requirements for high total pressure recovery and low bleed and cowl drag. However, since the optimum inlet for supersonic cruise performance may have other undesirable characteristics, it is necessary to establish trade-offs between inlet performance and other inlet characteristics. The paper will review some of these trade-offs between the amount of internal compression, aerodynamic performance and angle-of-attack tolerance. Also some techniques in use at the Lewis Research Center for analysis of boundary layer control and subsonic diffuser flow will be discussed.
Bowditch, D. N.↗
Evaluation of a new jet flap propulsive-lift system for turbofan-powered STOL transports
A large-scale STOL transport model with a new jet flap propulsive-lift system was subject to wind-tunnel testing. Aerodynamically, this IBF system combines the benefits of the jet flap and the mechanical flap with boundary layer control. Structurally, it creates its own spanwise air duct with the deflection of the mechanical flap. An additional short-chord control flap, located at the jet-flap exit, provides a powerful means for flight path and lateral controls. The results show that the overall effectiveness of this flap system compares well with other jet flap propulsive-lift systems. A preliminary study based on the wind-tunnel data was made on a medium-size IBF STOL jet transport configuration for a typical-military mission. This study showed that the IBF results in a configuration with a relatively low T/W ratio, making the system an attractive candidate for future designs.
Chin, Y. T.↗
Hybrid upper surface blown flap propulsive-lift concept for the quiet short-haul research aircraft
The hybrid upper surface blowing concept consists of wing-mounted turbofan engines with a major portion of the fan exhaust directed over the wing upper surface to provide high levels of propulsive lift, but with a portion of the fan airflow directed over selected portions of the airframe to provide boundary layer control. NASA-sponsored preliminary design studies identified the hybrid upper surface blowing concept as the best propulsive lift concept to be applied to the Quiet Short-Haul Research Aircraft (QSRA) that is planned as a flight facility to conduct flight research at low noise levels high approach lift coefficients, and steep approaches. Data from NASA in-house and NASA-sponsored small and large-scale wind tunnel tests of various configurations using this concept are presented.
Cochrane, J. A.↗
Interagency Workshop on Lighter than Air Vehicles, Monterey, Calif., September 9-13, 1974, Proceedings
Papers are presented which review modern lighter-than-air (LTA) airship design concepts and LTA structures and materials technology, as well as perform economic and market analyses for assessment of the viability of future LTA development programs. Potential applications of LTA vehicles are examined. Some of the topics covered include preliminary estimates of operating costs for LTA transports, an economic comparison of three heavy lift airborn systems, boundary layer control for airships, computer aided flexible envelope designs, state-of-the-art of metalclad airships, aspects of hybrid-Zeppelins, the LTA vehicle as a total cargo system, unmanned powered balloons, and a practical concept for powered or tethered weight-lifting LTA vehicles. Individual items are announced in this issue.
Vittek, J. F., Jr.↗
Aerodynamic characteristics of a large-scale hybrid upper surface blown flap model having four engines
Data are presented from an investigation of the aerodynamic characteristics of large-scale wind tunnel aircraft model that utilized a hybrid-upper surface blown flap to augment lift. The hybrid concept of this investigation used a portion of the turbofan exhaust air for blowing over the trailing edge flap to provide boundary layer control. The model, tested in the Ames 40- by 80-foot Wind Tunnel, had a 27.5 deg swept wing of aspect ratio 8 and 4 turbofan engines mounted on the upper surface of the wing. The lift of the model was augmented by turbofan exhaust impingement on the wind upper-surface and flap system. Results were obtained for three flap deflections, for some variation of engine nozzle configuration and for jet thrust coefficients from 0 to 3.0. Six-component longitudinal and lateral data are presented with four engine operation and with the critical engine out. In addition, a limited number of cross-plots of the data are presented. All of the tests were made with a downwash rake installed instead of a horizontal tail. Some of these downwash data are also presented.
Carros, R. J.↗
Hybrid upper surface blown flap propulsive-lift concept for the Quiet Short-Haul Research Aircraft
The hybrid upper surface blowing concept consists of wing-mounted turbofan engines with a major portion of the fan exhaust directed over the wing upper surface to provide high levels of propulsive lift, but with a portion of the fan airflow directed over selected portions of the airframe to provide boundary layer control. NASA-sponsored preliminary design studies identified the hybrid upper surface blowing concept as the best propulsive lift concept to be applied to the Quiet Short-Haul Research Aircraft (QSRA) that is planned as a flight facility to conduct flight research at low noise levels, high approach lift coefficients, and steep approaches. Data from NASA in-house and NASA-sponsored small and large-scale wind tunnel tests of various configurations using this concept are presented.
Cochrane, J. A.↗
Low-speed wind-tunnel investigation of a large scale advanced arrow-wing supersonic transport configuration with engines mounted above wing for upper-surface blowing
Tests have been conducted in a full scale tunnel to determine the low speed aerodynamic characteristics of a large scale advanced arrow wing supersonic transport configuration with engines mounted above the wing for upper surface blowing. Tests were made over an angle of attack range of -10 deg to 32 deg, sideslip angles of + or - 5 deg, and a Reynolds number range of 3,530,000 to 7,330,000. Configuration variables included trailing edge flap deflection, engine jet nozzle angle, engine thrust coefficient, engine out operation, and asymmetrical trailing edge boundary layer control for providing roll trim. Downwash measurements at the tail were obtained for different thrust coefficients, tail heights, and at two fuselage stations.
Shivers, J. P.↗
Effects of deflected thrust on the longitudinal aerodynamic characteristics of a close-coupled wing-canard configuration
The effects of power on the longitudinal aerodynamic characteristics of a close-coupled wing-canard fighter configuration with partial-span rectangular nozzles at the trailing edge of the wing were investigated. Data were obtained on a basic wing-strake configuration for nozzle and flap deflections from 0 deg to 30 deg and for nominal thrust coefficients from 0 to 0.30. The model was tested over an angle-of-attack range from -2 deg to 40 deg at Mach numbers of 0.15 and 0.18. Results show substantial improvements in lift-curve slope, in maximum lift, and in drag-due-to-lift efficiency when the canard and strakes have been added to the basic wing-fuselage (wing-alone) configuration. Addition of power increased both lift-curve slope and maximum lift, improved longitudinal stability, and reduced drag due to lift on both the wing-canard and wing-canard-strake configurations. These beneficial effects are primarily derived from boundary-layer control due to moderate thrust coefficients which delay flow separation on the nozzle and inboard portion of the wing flaps.
Yip, L. P.↗
Summary of low-speed aerodynamic characteristics of upper-surface-blown jet-flap configurations
The results of recent wind tunnel investigations to provide fundamental information on the upper surface blown (USB) jet flap concept demonstrated that the USB concept provides good high-lift performance. It is shown that the low speed performance is dependent upon the jet turning angle and turning efficiency and on the use of proper leading and trailing edge treatment to prevent premature flow separation. The best means of achieving good turning performance in any particular USB application must be determined from overall operational considerations in which high speed performance, structures and noise, as well as low speed performance, are evaluated. The large diving moments generated at high lift coefficients can be trimmed satisfactorily with a large, conventional horizontal tail; a high tail position is best from longitudinal stability considerations. Large rolling and yawing moments are introduced with the loss of an engine, but these moments can be trimmed satisfactorily through the use of asymmetrical boundary layer control and through the use of spoiler and rudder deflection as needed.
Phelps, A. E., III↗
Effects of inlet airframe integration on the inlet of an upper surface blowing four-engine STOL aircraft
Inlet and nacelle static pressures were measured on a 0.55-scale model of the Quiet Short-Haul Research Airplane (QSRA) in the Ames Research Center's 40- by 80-Foot Wind Tunnel. This model is powered by four JT-15D engines located above the wing with closely spaced adjacent inlets. A fifth JT-15D engine in the fuselage provides boundary-layer control air. Each inlet was instrumented with four to eight rows of axial pressure taps located between X/R approximately plus or minus 1. The tests simulated a broad range of aircraft operating conditions, including engine-out, with lift coefficients from 0.8 to 10.0. Results indicate that the inlets perform well under most operating conditions with little interaction between inlets when the aircraft is moving. Potential problem areas identified are high sideslip angle during approach and an interaction effect between adjacent inlets with high mass flows in static conditions.
Shovlin, M. D.↗
Design and performance of the propulsion system for the quiet short-haul research aircraft /QSRA/
This paper describes the design and performance of the Quiet Short-Haul Research Aircraft (QSRA) propulsion system. A discussion of the mixed-flow boundary layer control (BLC) system, which uses high and low pressure engine bleed air, is included. This system seriously affected propulsion system performance, particularly engine acceleration characteristics, requiring an integration of BLC system and powerplant controls. Funding limitations for the QSRA Project prevented extensive full-scale testing and systems mockups, resulting in a high reliance on small-scale tests and analytical techniques. Ground tests of the actual aircraft systems showed that the extrapolation of small-scale tests and analytical techniques were in good agreement with measured full-scale results.
Shovlin, M. D.↗
Evaluation of flow quality in two large NASA wind tunnels at transonic speeds
Wind tunnel testing of low drag airfoils and basic transition studies at transonic speeds are designed to provide high quality aerodynamic data at high Reynolds numbers. This requires that the flow quality in facilities used for such research be excellent. To obtain a better understanding of the characteristics of facility disturbances and identification of their sources for possible facility modification, detailed flow quality measurements were made in two prospective NASA wind tunnels. Experimental results are presented of an extensive and systematic flow quality study of the settling chamber, test section, and diffuser in the Langley 8 foot transonic pressure tunnel and the Ames 12 foot pressure wind tunnel. Results indicate that the free stream velocity and pressure fluctuation levels in both facilities are low at subsonic speeds and are so high as to make it difficult to conduct meaningful boundary layer control and transition studies at transonic speeds.
Harvey, W. D.↗
An investigation of the use of a propulsive wing/canard concept for improved maneuvering
The propulsive wing concept is an extension of the flap boundary layer control utilized on several aircraft configurations. Several studies have been made regarding the benefits of the propulsive wing in STOL operation. However, the propulsive wing/canard provides performance benefits also in areas other than STOL. It is expected to improve the maneuvering capability by providing reduced drag at high lift coefficients without appreciably affecting the low lift drag. An increase in the buffet free load factor can also be expected with the blown wing and canard. Attention is given to a program to investigate the wing/canard at maneuvering conditions, and tests at ranges of blowing coefficients equivalent to STOL operation.
Stewart, V. R.↗