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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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At least 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Wind tunnel and flight calibration of the Shuttle Orbiter air data system

The Space Shuttle Orbiter air data system has been subjected to wind tunnel testing including three subsonic tests and one reference probe calibration test in order to obtain preflight calibration. Calibration curves for angle of attack, static pressure, and total pressure are given in the 0.35-0.55 Mach number range which represents flight conditions. The major difficulties encountered concerned the reference pressure of the facility, model-probe scale discrepancies, tunnel changes and blockage effects. Actual flight data calibrations from the approach and landing test program were used to modify the wind tunnel calibrations.

Hillje, E. R.↗
NASA NTRS1977

Effect of flap deflection on the lift coefficient of wings operating in a biplane configuration

Biplane models with a lift flap were tested in a wind tunnel to study the effect of flap deflection on the aerodynamic coefficient of the biplane as well as of the individual wings. Optimization of the position flap was carried out, and the effect of changes in the chord length of the lower wing was determined for the aerodynamic structure of a biplane with a lift flap on the upper wing.

Stasiak, J.↗
NASA NTRS1992

Effect of blade planform variation on the forward-flight performance of small-scale rotors

An investigation was conducted in the Glenn L. Martin Wind Tunnel to determine the effect of blade planform variation on the forward-flight performance of four small-scale rotors. The rotors were 5.417 ft in diameter and differed only in blade planform geometry. The four planforms were: (1) rectangular; (2) 3:1 linear taper starting at 94 percent radius; (3) 3:1 linear taper starting at 75 percent radius; and (4) 3:1 linear taper starting at 50 percent radius. Each planform had a thrust-weighted solidity of 0.098. The investigation included forward-flight simulation at advance ratios from 0.14 to 0.43 for a range of rotor lift and drag coefficients. Among the four rotors, the rectangular rotor required the highest torque for the entire range of rotor drag coefficients attained at advanced ratios greater than 0.14 for rotor lift coefficients C sub L from 0.004 to 0.007. Among the rotors with tapered blades and for C sub L = 0.004 to 0.007, either the 75 percent tapered rotor or the 50 percent tapered rotor required the least amount of torque for the full range of rotor drag coefficients attained at each advance ratio. The performance of the 94 percent tapered rotor was generally between that of the rectangular rotor and the 75 and 50 percent tapered rotors at each advance ratio for this range of rotor lift coefficients.

Noonan, Kevin W.↗
NASA NTRS1946

Effect of Compressibility on the Pressure and Forces Acting on a Modified NACA 65,3-019 Airfoil Having A 0.20-Chord Flap

An investigation has been conducted in the Langley rectangular high-speed tunnel to determine the effect of compressibility on the pressure distribution for a modified NACA 65,3-019 airfoil having a 0.20-chord flap. The investigation was made for an angle-of-attack range extending from -2 to 12 deg at .20 flap deflections from 0 to -12 deg. Test data were obtained for Mach numbers from 0.28 to approximately 0.74. The results show that the effectiveness of the trailing-edge-type control surface rapidly decreased and approached zero as the Mach number increased above the critical value.

AIRFOILS-NACA 65,3-019 (MOD )-MOMENTS & ORDINATES ↗
NASA NTRS1983

Three-dimensional effects on airfoils

The effects of boundary layer flows along the walls of wind tunnels were studied to validate the transfer of two dimensional calculations to three dimensional transonic flowfield calculations. Results from trials in various wind tunnels were examind to determine the effects of the wall boundary flow on the control surfaces of an airfoil. Models sliding along a groove in the wall of a channel at sub- and transonic speeds were examined, with the finding that with either nonuniformities in the groove, or even if the channel walls are uniform, the lateral boundary layer can cause variations in the central flow region or alter the onset of shock at the transition point. Models for the effects in both turbulence and in the absence of turbulence are formulated, and it is noted that the characteristics of individual wind tunnels must be studied to quantify any existing three dimensional effects.

Chevallier, J. P.↗
NASA NTRS1986

Effects of upper-surface nacelles on longitudinal aerodynamic characteristics of high-wing transport configuration

An investigation has been conducted in the Langley 16-Foot Transonic Tunnel to determine the effects of installing and streamline contouring upper-surface nacelles on the longitudinal aerodynamic characteristics of a high-wing transport configuration. Also investigated were the effects of adding a fairing under the nacelle. The investigation was conducted at free-stream Mach numbers from 0.60 to 0.83 at angles fo attack from -2 deg to 4 deg. Flow-through nacelles were used. Streamline contouring the nacelles substantially reduced the interference drag due to installing the nacelles.

Putnam, L. E.↗
NASA NTRS1987

Effects of the installation and operation of jet-exhaust yaw vanes on the longitudinal and lateral-directional characteristics of the F-14 airplane

A wind tunnel investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effects of the installation and use of jet exhaust yaw vanes on the longitudinal and lateral-directional characteristics of the F-14 aircraft. The model was tested at Mach numbers from 0.70 to 1.25 at angles of attack from 0 deg to 4.3 deg. Compressed air was used to simulate nozzle exhaust flow from jet off up to a nozzle pressure ratio of 8. The results of the investigation show that the yaw vanes can augment the rudders to provide directional control, but further investigation will be necessary to optimize the deflection schedule associated with the various nozzle power settings.

Reubush, David E.↗
NASA NTRS1936

Effect of changes in tail arrangement upon the spinning of a low-wing monoplane model

A series of tests was made in the N.A.C.A. free spinning tunnel to find the effect upon spinning characteristics of systematic changes in tail arrangement. The tests were made with a 1/16-scale made of a low-wing monoplane of modern design. The changes consisted of: (1) variation of the fuselage length; (2) variation of the fore-and-aft location of the vertical surfaces; and (3) variation of the vertical location of the horizontal surfaces. The spinning characteristics of the model, including the number of turns required for recovery, were found to vary systematically and regularly with systematic changes in the tail arrangement. The following changes in tail arrangement had harmful effects upon the recovery characteristics (which originally were excellent): (1) shortening the fuselage; (2) placing the vertical surfaces directly above the horizontal surfaces as compared with locations either fore or aft of this position; (3) moving the horizontal surfaces downward from their original location at the top of the fuselage.

Zimmerman, C H↗
NASA NTRS1978

Flight-determined stability and control coefficients of the F-111A airplane

A complete set of linear stability and control derivatives of the F-111A airplane was determined with a modified maximum likelihood estimator. The derivatives were determined at wing sweep angles of 26 deg, 35 deg, and 58 deg. The flight conditions included a Mach number range of 0.63 to 1.43 and an angle of attack range of 2 deg to 15 deg. Maneuvers were performed at normal accelerations from 0.9g to 3.8g during steady turns to assess the aeroelastic effects on the stability and control characteristics. The derivatives generally showed consistent trends and reasonable agreement with the wind tunnel estimates. Significant Mach effects were observed for Mach numbers as low as 0.82. No large effects attributable to aeroelasticity were noted.

Iliff, K. W.↗
NASA NTRS1999

Application of Forebody Strakes for Directional Stability and Control of Transport Aircraft

A brief overview of a cooperative NASA/Boeing research effort, Strake Technology Research Application to Transport Aircraft (STRATA), intended to explore the potential of applying forebody strake technology to transport aircraft configurations for directional stability and control at low angles of attack, is presented. As an initial step in the STRATA program, an exploratory wind-tunnel investigation of the effect of fixed forebody strakes on the directional stability and control characteristics of a generic transport configuration was conducted in the NASA Langley 12-Foot Low-Speed Wind Tunnel. Results of parametric variations in strake chord and span, as well as the effect of strake incidence, are presented. The use of strakes for yaw control is also discussed. Results emphasize the importance of forebody/fuselage crossflow in influencing strake effectiveness. Strake effectiveness is also seen to be directly related to its span, but less sensitive to chord; a very short-chord strake with sufficient span can have a significant effect.

Shah, Gautam H.↗
NASA NTRS1974

Experimental study of the effectiveness of cylindrical plume simulators for predicting jet-on boattail drag at Mach numbers up to 1.30

An investigation has been conducted in a 16-foot transonic tunnel to determine the effectiveness of utilizing solid circular cylinders to simulate the jet exhaust plume for a series of eight nacelle-mounted isolated circular-arc afterbodies. This investigation was conducted at Mach numbers from 0.40 to 1.30 at an angle of attack of 0. Plume simulators with simulator diameter to nozzle-exit diameter ratios of 0.82, 0.88, 0.98, and 1.00 were investigated. Results of this investigation indicate that use of one of the larger diameter simulators at all Mach numbers would generally result in pressure-coefficient distributions and drag coefficients useful for preliminary design work.

Reubush, D. E.↗
NASA NTRS1979

An Exploratory Investigation of the Effect of Plastic Coating on the Profile Drag of a Practical-Metal-Construction Sailplane Airfoil

An exploratory investigation was performed in the Langley low-turbulence pressure tunnel to determine the effect of a plastic coating on the profile drage of a practical-metal-construction sailplaine airfoil. The mode was tested with three surface configurations: (1) filled, painted, and sanded smooth; (2) rough bare metal; and (3) plastic-coated. The investigation was conducted at Reynolds numbers based on airfoil chord of 1,100,000, 2,200,000, and 3,300,000 at a constant Mach number of 0.10. The results indicate that, at all three Reynolds numbers, the order of the drag values of the three surface configurations, starting with the highest drag, was: filled, painted, and sanded smooth; rough bare metal; and plastic-coated.

Somers, D. M.↗
NASA NTRS1984

Effects of tail span and empennage arrangement on drag of a typical single-engine fighter aft end

An investigation was conducted in the Langley 16 foot Transonic Tunnel to determine the effects of tail span and empennage arrangement on drag of a single engine nozzle/afterbody model. Tests were conducted at Mach numbers from 0.50 to 1.20, nozzle pressures frm 1.0 (jet off) to 8.0, and angles of attack from -3 to 9 deg, depending upon Mach numbers. Three empennage arrangements (aft, staggered, and forward) were investigated with several different tail spans. The results of the investigation indicate that tail span and position have a significant effect on the drag at transonic speeds. Unfavorable tail interference was largely due to the outer portion of the tail surfaces. The inner portion near the nozzle and afterbody did little to increase drag other than surface skin friction. Tail positions forward of the nozzle generally had lower tail interference.

Burley, J. R., II↗
NASA NTRS1987

Effect of a trade between boattail angle and wedge size on the performance of a nonaxisymmetric wedge nozzle

An investigation was conducted in the Langley 16-Foot Transonic Tunnel to determine the effect of a boattail angle and wedge-size trade on the performance of nonaxisymmetric wedge nozzles installed on a generic twin-engine fighter aircraft model. Test data were obtained at static conditions and at Mach numbers from 0.60 to 1.25. Angle of attack was held constant at 0 deg. High-pressure air was used to simulate jet exhaust, and the nozzle pressure ratio was varied from 1.0 (jet off) to slightly over 15.0. For the configurations studied, the results indicate that wedge size can be reduced without affecting aeropropulsive performance.

Carson, George T., Jr.↗
NASA NTRS1933

The Effect of Rivet Heads on the Characteristics of a 6 by 36 Foot Clark Y Metal Airfoil

An investigation was conducted in the N.A.C.A. full-scale wind tunnel to determine the effects of exposed rivet heads on the aerodynamic characteristics of a metal-covered 6 by 36 foot Clasky airfoil. Lead punching simulating 1/8inch rivet heads were attached in full-span rows at a pitch of 1 inch at various chord positions. Tests were made at velocities varying from 40 to 120 miles per hour to investigate the scale effect. Rivets at the 5 percent chord position the upper surface of the airfoil produced the greatest increase in drag for a single row. Nine rows of rivets on both surfaces, simulating rivet spacing of multispan construction, increased the drag coefficients by a constant amount at velocities between 100 and 120 miles per hour. Accordingly, if rivets spaced the same as those on the test airfoil were used on a Clark Y wing of 300 square feet area and operated at 200 miles per hour, the drag would be increased over that for the smooth wing by 55 pounds and the power required would be increased by 29 horsepower.

Dearborn, Clinton H↗