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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Space shuttle: Static stability and control investigation of NR/GD delta wing booster (B-20) and delta wing orbiter (134D), volume 1

Experimental aerodynamic investigations have been made on a .0035 scale model North American Rockwell/General Dynamics version of the space shuttle. Static stability and control data were obtained on the delta wing booster alone (B-20) and with the delta wing orbiter (134D) mounted in various positions on the booster. Six component aerodynamic force and moment data were recorded over an angle of attack range from -10 deg to 24 deg at 0 deg and 6 deg sideslip angles and from -10 deg to +10 deg sideslip at 0 deg angle of attack. Mach number ranged from 0.6 to 4.96.

Allen, E. C.↗
NASA NTRS1972

Space shuttle: Static stability and control investigation of NR/GD delta wing booster (B-20) and delta wing orbiter (134-D), volume 3

Experimental aerodynamic investigations have been made on a .0035 scale model North American Rockwell/General Dynamics version of the space shuttle in the NASA/MSFC 14 x 14 Inch Trisonic Wind Tunnel. Static stability and control data were obtained on the delta wing booster alone (B-20) and with the delta wing orbiter (134D) mounted in various positions on the booster. Six component aerodynamic force and moment data were recorded over an angle of attack range from -10 to 24 deg at 0 and 6 deg sideslip angles and from -10 to +10 deg sideslip at 0 deg angle of attack. Mach number ranged from 0.6 to 4.96.

Allen, E. C., Jr.↗
NASA NTRS1981

Self-induced wing rock of slender delta wings

As part of a research program aimed at exploring basic mechanisms that cause wing rock in combat aircraft, an investigation was conducted to study the aerodynamic factors which cause the low-speed wing rock exhibited by slender delta wings. A flat-plate delta wing with 80 deg leading-edge sweep was subjected to conventional static-force tests and dynamic wind-tunnel experiments which included forced-oscillation, rotary, and free-to-roll tests. In addition, visualization of the flow phenomena involved was obtained by observing tuft patterns and using a helium-bubble technique. This paper summarizes the results of this study. Fundamental information is presented on the aerodynamic mechanisms that cause the wing rock and the problem of mathematically modeling the aerodynamics and motions is discussed.

Nguyen, L. T.↗
NASA NTRS1993

An aerodynamic model for one and two degree of freedom wing rock of slender delta wings

The unsteady aerodynamic effects due to the separated flow around slender delta wings in motion were analyzed. By combining the unsteady flow field solution with the rigid body Euler equations of motion, self-induced wing rock motion is simulated. The aerodynamic model successfully captures the qualitative characteristics of wing rock observed in experiments. For the one degree of freedom in roll case, the model is used to look into the mechanisms of wing rock and to investigate the effects of various parameters, like angle of attack, yaw angle, displacement of the separation point, and wing inertia. To investigate the roll and yaw coupling for the delta wing, an additional degree of freedom is added. However, no limit cycle was observed in the two degree of freedom case. Nonetheless, the model can be used to apply various control laws to actively control wing rock using, for example, the displacement of the leading edge vortex separation point by inboard span wise blowing.

Hong, John↗
NASA NTRS1991

Conical Euler simulation of wing rock for a delta wing planform

Unsteady, vortex-dominated flowfields are presently studied by using the conical Euler equations as an efficient first step toward investigation of the full three-dimensional problem, under the assumption that the supersonic flow about a delta wing is conical and therefore allows the three-dimensional problem to be reduced to a two-dimensional one. Attention is given to the case of a delta wing undergoing wing-rock motion. The code developed has also been modified to allow treatment of the 'free-to-roll' case.

Lee, Elizabeth M.↗
NASA NTRS1977

Effects of external stores on the air combat capability of a delta wing fighter

Delta wing point-design fighters with two pylon mounted missiles and aft tail controls (similar to several Soviet designs) have been investigated for a Mach number range from about 0.6 to 2.0. Whereas minimum drag penalties that are expected with the addition of external stores do occur, the effects at higher lifts, corresponding to maneuvering flight, are less severe and often favorable. The drag-due-to-lift factor is less with stores on although the lift curve slope is unaffected. The longitudinal stability level is reduced by the addition of stores while the pitch control effectiveness is unchanged. The directional stability was generally reduced at subsonic speeds and increased at supersonic speeds by the addition of stores but sufficiently high stability levels are obtainable that are compatible with the longitudinal maneuvering limits. Some examples of the potential maneuvering capability in terms of normal acceleration and turn radius are included.

Spearman, M. L.↗
NASA NTRS1993

Active control of wing rock of a delta wing at post-stall using tangential leading edge blowing

Post-stall roll control utilizing tangential leading edge blowing is demonstrated in a wind tunnel on a delta wing model that exhibited wing rock. The dampening effect of symmetric blowing alone on wing rock is found to be effective up to a certain maximum amount of blowing. A moderate amount of symmetric blowing was shown to be effective in linearizing the asymmetric blowing static rolling moment responses.

Wong, G. S.↗
NASA NTRS1993

A study of roll attractor and wing rock of delta wings at high angles of attack

Wing rock is a high angle of attack dynamic phenomenon of limited cycle motion predominantly in roll. The wing rock is one of the limitations to combat effectiveness of the fighter aircraft. Roll Attractor is the steady state or equilibrium trim angle (phi(sub trim)) attained by the free-to-roll model, held at some angle of attack, and released form rest at a given initial roll (bank) angle (phi(sub O)). Multiple roll attractors are attained at different trim angles depending on initial roll angle. The test facility (Vigyan's low speed wind tunnel) and experimental work is presented here along with mathematical modelling of roll attractor phenomenon and analysis and comparison of predictions with experimental data.

Niranjana, T.↗
NASA NTRS2002

A Discrete-Vortex Method for Studying the Wing Rock of Delta Wings

A discrete-vortex method is developed to investigate the wing rock problem associated with highly swept wings. The method uses two logarithmic vortices placed above the wing to represent the vortex flow field and uses boundary conditions based on conical flow, vortex rate of change of momentum, and other considerations to position the vortices and determine their strengths. A relationship based on the time analogy and conical-flow assumptions is used to determine the hysteretic positions of the vortices during roll oscillations. Static and dynamic vortex positions and wing rock amplitudes and frequencies calculated by using the method are generally in good agreement with available experimental data. The results verify that wing rock is caused by hysteretic deflections of the vortices and indicate that the stabilizing moments that limit wing rock amplitudes are the result of the one primary vortex moving outboard of the wing where it has little influence on the wing.

Gainer, Thomas G.↗
NASA NTRS1983

Wing loading on a 60 degree delta wing with vortex flaps

Wind tunnel tests were conducted on a 60 deg delta wing with three vortex flap designs to determine pressure distributions over the wing and flap. The results showed that an optimum vortex flap design depends on proper definition of the vortex flap deflection angle. They also revealed that flap thickness plays an important role in the behavior of the vortex flow over the flap and wing and can have a substantial effect on wing and flap pressure loading. Design codes which fail to account for thickness may result in a much less than optimum flap and deprive the designer of an important tool in designing an effective flap with optimum loading.

Marchman, J. F., III↗