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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

High Reynolds Number Effects on HSCT Stability and Control Characteristics

Two wind tunnel tests during 1995 in the National Transonic Facility (NTF 070 and 073) served to define Reynolds number effects on longitudinal and lateral-directional stability and control. Testing was completed at both high lift and transonic conditions. The effect of Reynolds number on the total airplane configuration, horizontal and vertical tail effectiveness, forebody chine performance, rudder control and model aeroelastics was investigated. This paper will present pertinent stability and control results from these two test entries. Note that while model aeroelastic effects are examined in this presentation, no corrections for these effects have been made to the data.

Elzey, Michael B.↗
NASA NTRS1975

Transonic wind-tunnel tests of an F-8 airplane model equipped with 12 and 14-percent thick oblique wings

An experimental investigation was conducted in the Ames 14-foot transonic wind tunnel to study the aerodynamic performance and stability characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing. Two elliptical planform (axis ratio = 8:1) wings, each having a maximum thickness of 12 and 14 percent, were tested. Longitudinal stability data were obtained with no wing and with each of the two wings set at sweep angles of 0, 45, and 60 deg. Lateral directional stability data were obtained for the 12 percent wing only. Test Mach numbers ranged from 0.6 to 1.2 in the unit Reynolds number range from 11.2 to 13.1 million per meter. Angles of attack were between -6 and 22 deg at zero sideslip. Angles of sideslip were between -6 and +6 deg for two angles of attack, depending upon the wing configuration.

Smith, R. C.↗
NASA NTRS1986

Low-speed stability and control characteristics of a transport model with aft-fuselage-mounted advanced turboprops

A limited experimental investigation was conducted in the Langley 4- by 7-Meter Tunnel to explore the effects of aft-fuselage-mounted advanced turboprop installations on the low-speed stability and control characteristics of a representative transport aircraft in a landing configuration. In general, the experimental results indicate that the longitudinal and lateral-directional stability characteristics for the aft-fuselage-mounted single-rotation tractor and counter-rotation pusher propeller configurations tested during this investigation are acceptable aerodynamically. For the single-rotation tractor configuration, the propeller-induced aerodynamics are significantly influenced by the interaction of the propeller slipstream with the pylon and nacelle. The stability characteristics for the counter-rotation pusher configuration are strongly influenced by propeller normal forces. The longitudinal and directional control effectiveness, engine-out characteristics, and ground effects are also presented. In addition, a tabulated presentation of all aerodynamic data presented in this report is included as an appendix.

Applin, Z. T.↗
NASA NTRS1976

Aerodynamic characteristics of a 1/6-scale model of the rotor systems research aircraft with the rotors removed

A wind-tunnel investigation was conducted to refine the aerodynamic characteristics of the rotor systems research aircraft. For the investigation, a 1/6-scale model without a main rotor or a tail rotor was used. The model provided the capability for testing different engine nacelle sizes, engine pylon fairings, and tail configurations. The engine thrust effects were modeled by small engine simulators (fans). Data were obtained primarily over an angle-of-attack range from -13 deg to 13 deg at several values of sideslip. Stability characteristics and control effectiveness were investigated. The model with the scaled engine nacelles and the combination T-tail and lower horizontal tail displayed longitudinal and lateral-directional stability. Results show that by reducing the horizontal or vertical-tail span the longitudinal stability is decreased. Reducing the engine nacelle size increases the static stability of the model. Effective dihedral is essentially zero at 0 deg angle of attack and 0 deg wing incidence.

Mineck, R. E.↗
NASA NTRS1981

Effects of wingtip modifications on handling qualities of agricultural aircraft

The effect of wingtip modifications on the stability and control characteristics of an agricultural airplane has been studied by means of a nonplanar quasi-vortex-lattice method. The method is used to compute the changes in steady state and perturbed state lateral-directional stability and control derivatives produced by wingtip mounted winglets, vortex diffuser vanes, and tip extensions. The study shows that the combination of the excessive positive dihedral effect produced by the winglets and adverse yaw due to aileron deflection can have a detrimental effect on the roll control characteristics of the airplane. Introduction of an aileron-rudder-interconnect, and reduction of the effective dihedral by canting-in of the winglets, or addition of a lower winglet can eliminate the roll control problems.

Van Dam, C. P.↗
NASA NTRS1985

Exploratory low-speed wind-tunnel study of concepts designed to improve aircraft stability and control at high angles of attack

A wind tunnel investigation of concepts to improve the high angle-of-attack stability and control characteristics of a high performance aircraft was conducted. The effect of vertical tail geometry on stability and the effectiveness of several conventional and unusual control concepts was determined. These results were obtained over a large angle-of-attack range. Vertical tail location, cant angle and leading edge sweep could influence both longitudinal and lateral-directional stability. The control concepts tested were found to be effective and to provide control into the post stall angle-of-attack region.

Hahne, D. E.↗
NASA NTRS1973

An experimental investigation of three oblique-wing and body combinations at Mach numbers between 0.60 and 1.40

An experimental investigation was conducted in an 11- by 11-foot transonic wind tunnel to determine the aerodynamic characteristics of three oblique high aspect ratio wings in combination with a high fineness-ratio Sears-Haack body. The three wings had the same elliptical planform and base line curvature but had different airfoil sections. One wing had an airfoil section designed to have a lift coefficient of 1.0 at a Mach number of 0.7, another to have shock-free supersonic flow over the upper surface, and the other to have a lift coefficient of 1.3 at a Mach number of 0.6. Longitudinal and lateral-directional stability data were obtained at wing yaw angles of 0 deg, 45 deg, 50 deg, and 60 deg over a test Mach number range from 0.6 to 1.4 for angles of attack between minus 7 deg and 9 deg. Reynolds numbers for the study were 4 and 6 million per foot. Flow-visualization studies were made to examine the nature of the flow on the wing surfaces. Notable differences were found in the aerodynamic characteristics of the three wing-body combinations, particularly in the lateral-directional characteristics.

Graham, L. A.↗
NASA NTRS1974

Investigation of space shuttle orbiter subsonic stability and control characteristics and determination of control surface hinge moments in the Rockwell International low speed wind tunnel (OA37)

Experimental aerodynamic investigations were conducted on a string-mounted 0.030 scale representation of the 140A/B space shuttle orbiter in the 7.75- by 11-foot low speed wind tunnel. The primary test objectives were to establish basic longitudinal and lateral directional stability and control characteristics for the basic configuration plus control surface hinge moments. Aerodynamic force and moment data were measured in the body axis system by an internally mounted, six-component strain gage balance. Additional configurations investigated were sealed rudder hingeline gaps, sealed elevon gaps and compartmentized speedbrakes.

Hughes, T.↗
NASA NTRS1974

Stability and control characteristics for the inner mold line configuration of the space shuttle orbiter (OA110)

Experimental aerodynamic investigations were conducted on a sting mounted 0.0405-scale representation of the -140A/B inner mold line (IML) space shuttle orbiter in 7.75 x 11 foot low speed wind tunnel, during the time period from 18 March 1974 to 20 March 1974. The primary test objectives were to establish basic longitudinal and lateral-directional stability and control characteristics for the IML orbiter. Additional configurations investigated were sealed elevon hingeline gaps, sealed rudder split line and hingeline gaps, larger radius leading edge on the vertical tail, and sealed speedbrake base. Aerodynamic force and moment data for the orbiter were measured in the body-axis system by an internally mounted, six-component strain gage balance. The model was sting mounted with the center of rotation located at approximately the wing trailing edge. The nominal angle of attack range was from -4 to +30 degrees. Yaw polars were recorded over a nominal yaw angle range from -14 to +14 degrees at constant angles of attack of 0, + or - 5, 10, 15 and 20 degrees.

Hughes, T.↗
NASA NTRS1988

Lateral stability and control derivatives extracted from space shuttle Challenger flight data

Flight data taken from six flights of the Space Transportation System shuttle Challenger (STS-6, 7, 8, 11, 13 and 17) during atmospheric entry are analyzed to determine the shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The vehicle stability and control surface effectiveness are compared across the flights and to preflight predicted values.

Schiess, James R.↗
NASA NTRS1986

Lateral stability and control derivatives extracted from five early flights of the space shuttle Columbia

Flight data taken from the first five flights (STS-2, 3, 4, 5 and 9) of the Space Transportation System Shuttle Columbia during entry are analyzed to determine the Shuttle lateral aerodynamic characteristics. Maximum likelihood estimation is applied to data derived from accelerometer and rate gyro measurements and trajectory, meteorological and control surface data to estimate lateral-directional stability and control derivatives. The estimated parameters are compared across the five flights and to preflight predicted values.

Schiess, J. R.↗
NASA NTRS1973

Wind tunnel tests of an F-8 airplane model equipped with an oblique wing

An experimental investigation was conducted in an 11- by 11-foot transonic wind tunnel to study the lift, drag and stability characteristics of a 0.087-scale model of an operational airplane fitted with an oblique wing. The model wing was of elliptical planform with an unswept aspect ratio of 12.7 and a thickness of 10 percent. All other external geometric features of the model were scaled to the basic full size operational airplane with the engine inlet faired closed. Longitudinal and lateral-directional stability data were obtained with the wing at sweep angles of 0 deg, 45 deg and 60 deg Test Mach numbers ranged from 0.6 to 1.4 deg Angles of attack were between minus 4 deg and 8 deg at zero sideslip. Angles of sideslip were between plus and minus 4 degrees for two angles of attack depending upon the wing configuration. Tests were conducted at a Reynolds number of 6 million per foot except for a few runs when balance capacity limited the Reynolds number to 4 million per foot.

Graham, L. A.↗
NASA NTRS1973

The results of low-speed wind tunnel tests to investigate the effects of the NASA refan JT8D engine nacelles on the stability and control characteristics of the Boeing 727-200

The results from two low-speed wind tunnel tests of the Boeing 727-200 airplane as configured with the NASA refan JT8D-109 turbofan engines are presented. The objective of these tests was to determine the effects of the refan installation on the low-speed stability and control characteristics of the 727 airplane. Four side nacelle locations were tested to insure that aerodynamic interactions of the nacelles and empennage would be optimized. The optimum location was judged to be the same as that of the production JT8D-9 engines; the current production engine mounts can be used for this location. Some small changes in the basic airplane characteristics are attributable to the refan nacelles. The flaps up longitudinal and lateral-directional stability are both slightly increased for low angles of attack and sideslip respectively. The longitudinal stability at stall is improved for both the flaps up and landing flap configurations. The high attitude characteristics of the basic airplane are not significantly altered by the refan nacelle installation. Directional control capability is not affected by the refan nacelles.

Shirkey, M. D.↗
NASA NTRS1999

Experimental Aerodynamic Characteristics of an Oblique Wing for the F-8 OWRA

An experimental investigation was conducted during June-July 1987 in the NASA Ames 11-Foot Transonic Wind Tunnel to study the aerodynamic performance and stability and control characteristics of a 0.087-scale model of an F-8 airplane fitted with an oblique wing. This effort was part of the Oblique Wing Research Aircraft (OWRA) program performed in conjunction with Rockwell International. The Ames-designed, aspect ratio 10.47, tapered wing used specially designed supercritical airfoils with 0.14 thickness/chord ratio at the root and 0.12 at the 85% span location. The wing was tested at two different mounting heights above the fuselage. Performance and longitudinal stability data were obtained at sweep angles of 0deg, 30deg, 45deg, 60deg, and 65deg at Mach numbers ranging from 0.30 to 1.40. Reynolds number varied from 3.1 x 10(exp 6)to 5.2 x 10(exp 6), based on the reference chord length. Angle of attack was varied from -5deg to 18deg. The performance of this wing is compared with that of another oblique wing, designed by Rockwell International, which was tested as part of the same development program. Lateral-directional stability data were obtained for a limited combination of sweep angles and Mach numbers. Sideslip angle was varied from -5deg to +5deg. Landing flap performance was studied, as were the effects of cruise flap deflections to achieve roll trim and tailor wing camber for various flight conditions. Roll-control authority of the flaps and ailerons was measured. A novel, deflected wing tip was evaluated for roll-control authority at high sweep angles.

Kennelly, Robert A., Jr.↗
NASA NTRS1986

Natural laminar flow and airplane stability and control

Location and mode of transition from laminar to turbulent boundary layer flow have a dominant effect on the aerodynamic characteristics of an airfoil section. The influences of these parameters on the sectional lift and drag characteristics of three airfoils are examined. Both analytical and experimental results demonstrate that when the boundary layer transitions near the leading edge as a result of surface roughness, extensive trailing-edge separation of the turbulent boundary layer may occur. If the airfoil has a relatively sharp leading-edge, leading-edge stall due to laminar separation can occur after the leading-edge suction peak is formed. These two-dimensional results are used to examine the effects of boundary layer transition behavior on airplane longitudinal and lateral-directional stability and control.

Vandam, Cornelis P.↗
NASA NTRS1977

Augmentation of maneuver performance by spanwise blowing

A generalized wind tunnel model was tested to investigate new component concepts utilizing spanwise blowing to provide improved maneuver characteristics for advanced fighter aircraft. Primary emphasis was placed on high angle of attack performance, stability, and control at subsonic speeds. Spanwise blowing on a 44 deg swept trapezoidal wing resulted in leading edge vortex enhancement with subsequent large vortex-induced lift increments and drag polar improvements at the higher angles of attack. Small deflections of a leading edge flap delayed these lift and drag benefits to higher angles of attack. In addition, blowing was more effective at higher Mach numbers. Spanwise blowing in conjunction with a deflected trailing edge flap resulted in lift and drag benefits that exceeded the summation of the effects of each high lift device acting alone. Asymmetric blowing was an effective lateral control device at the higher angles of attack. Spanwise blowing on the wing reduced horizontal tail loading and improved the lateral-directional stability characteristics of a wing-horizontal tail-vertical tail configuration.

Erickson, G. E.↗
NASA NTRS1972

Aerodynamic studies of delta-wing shuttle orbiters. Part 1: Low speed

Numerous wind tunnel tests conducted on the evolving delta-wing orbiters have generated a fairly large aerodynamic data base over the entire entry operation range of these vehicles. A limited assessment is made of some of the aerodynamics of the current HO type orbiters, and several specific problem areas selected from the broad data base are discussed. These include, from a subsonic viewpoint, discussions of trim drag effect; effects of the installation of main rocket engine nozzles, OMS and RCS packages, Reynolds number effects, lateral-directional stability characteristics, and landing characteristics.

Freeman, D. C., Jr.↗