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At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1953

Investigation of the Effects of Propeller Operation on the Low-Speed Stability and Control Characteristics of a 1/6-Scale Model of a Revised Configuration of the Republic XF-84H Airplane

An investigation was made to determine the static longitudinal and lateral stability and control characteristics of a l/6-scale model of the revised Republic XF-84H airplane with and without the propeller operating. The model had a 40deg swept wing of aspect ratio 3.45 and was equipped with a thin, three-blade supersonic-type propeller. Modifications incorporated in the revised model included a raised horizontal tail, increased rudder size, wing fences at 65 percent semispan, and a modified wing leading edge outboard of the fences. The test results for flap-retracted and flap-deflected conditions indicated that the revised configuration should be satisfactory for most normal flight conditions provided the angle of attack does not exceed the angle for pitch-up. An abrupt pitch-up tendency of the model was evident for the zero thrust condition above approximately 15' angle of attack. Although the effects of power were destabilizing, power-on longitudinal stability was satisfactory through the angle-of-attack range for which the model was stable with zero thrust. Above the angle of attack for pitch-up, an uncontrollable left roll-off tendency would be expected with power on and slats retracted. Projection of wing slats or use of leading-edge chord-extensions with only the left extension drooped were found beneficial in controlling the roll-off tendency with power on; however the most effective means found was projection of only the left slat.

Sleeman, William C., Jr.↗
NASA NTRS1948

An Investigation of the Low-speed Static Stability Characteristics of Complete Models Having Sweptback and Sweptforward Wings

An investigation has been conducted in the Langley 300 MPH 7- by 10-foot tunnel to determine the static stability characteristics at low speeds of complete models with various swept wings so that comparisons might be made with available theoretical and empirical methods of predicting the stability characteristics. Longitudinal and lateral stability characteristics, flaps up and down, were obtained for models having 0 degree, 15 degrees, 30 degrees, and 45 degrees sweptforward and sweptback wings.

SWEEP - COMPLETE WINGS↗
NASA NTRS1949

Wind-Tunnel Investigation of the Low-Speed Static Stability and Control Characteristics of a Model of the Bell MX-776 (RASCAL) in Combined Angle of Attack and Sideslip

An investigation has been made in the Langley stability tunnel to determine the low-speed static stability and control characteristics of a model of the Bell MX-776. The results show the model to be longitudinally unstable in the angle-of-attack range around zero angle of attack and to become stable at moderate angles of attack. The results of the present investigation agree reasonably well with results obtained in other facilities at low speed. The present pitching-moment results at low Mach numbers also agree reasonably well with unpublished results of tests of the model at supersonic Mach numbers (up to Mach number 1.86). Unpublished results at moderate and high subsonic speeds, however, indicate considerably greater instability at low angles of attack than is indicated by low-speed results. The results of the present tests also showed that the pitching-moment coefficients for angles of attack up to 12deg remained fairly constant with sideslip angle up to 12deg. The elevators tested produced relatively large pitching moments at zero angle of attack but, as the angle of attack was increased, the elevator effectiveness decreased. The rate of decrease of elevator effectiveness with angle of attack was less for 8deg than for 20deg elevator deflection. Therefore although 8deg deflection caused an appreciable change in longitudinal trim angle and trim lift coefficient a deflection of 20deg caused only a small additional increase in trim angle and trim lift coefficient.

Letko, William↗
NASA NTRS1949

Wind-Tunnel Investigation of the Low-Speed Static Stability and Control Characteristics of a Model of Bell MX-776

An investigation has been made in the Langley stability tunnel to determine the low-speed static stability and control characteristics of a model of the Bell MX-776. The results of the investigation indicated that the basic model configuration was longitudinally stable in the angle-of-attack range from about -16 deg. to 16 deg. but that the stability was a minimum near O deg angle of attack. The data indicated an aerodynamic-center position about 0.64 body diameters behind the center of gravity at low angles of attack. Reduction in the size of the front horizontal fins increased the longitudinal stability. With 20 percent of the span of the normal front horizontal fins cut off the aerodynamic center was about 1.04 body diameters behind the center of gravity, and with front horizontal fins having the same area as the front vertical fins, the aerodynamic center was 2.26 body diameters behind the center of gravity (at low angles of attack).

Queijo, M. J.↗
NASA NTRS1951

Wind-tunnel investigation of the effects of horizontal-tail position on the low-speed longitudinal stability characteristics of an airplane model with a 35 degrees sweptback wing equipped with chordwise fences

An experimental investigation was made in the Langley stability tunnel to determine whether the low-speed longitudinal stability characteristics of a model with a 35 degree sweptback wing could be improved appreciably by lowering the horizontal tail. The investigation included tests of several components of the model and of various model configurations with chordwise fences on the wing.

Queijo, M J↗
NASA NTRS1958

Low-Speed Static Stability Characteristics of Two Configurations Suitable for Lifting Reentry from Satellite Orbit

An investigation of the low-speed static stability and control characteristics of 1/4-scale models of two configurations suitable for lifting reentry from satellite orbit has been made in the Langley free- flight tunnel. One of the models was a thick, all-wing configuration having a delta plan form and the other was a flat delta wing with a half-cone fuselage. The investigation showed that, in general, the all-wing configuration had better longitudinal and lateral stability characteristics than the flat delta configuration.

Paulson, John W.↗
NASA NTRS1974

Wind-tunnel investigation to determine the low speed yawing stability derivatives of a twin jet fighter model at high angles of attack

An investigation was conducted to determine the low-speed yawing stability derivatives of a twin-jet fighter airplane model at high angles of attack. Tests were performed in a low-speed tunnel utilizing variable-curvature walls to simulate pure yawing motion. The results of the study showed that at angles of attack below the stall the yawing derivatives were essentially independent of the yawing velocity and sideslip angle. However, at angles of attack above the stall some nonlinear variations were present and the derivatives were strongly dependent upon sideslip angle. The results also showed that the rolling moment due to yawing was primarily due to the wing-fuselage combination, and that at angles of attack below the stall both the vertical and horizontal tails produced significant contributions to the damping in yaw. Additionally, the tests showed that the use of the forced-oscillation data to represent the yawing stability derivatives is questionable, at high angles of attack, due to large effects arising from the acceleration in sideslip derivatives.

Coe, P. L., Jr.↗
NASA NTRS1959

Low-Speed Static Stability and Control Characteristics of a Model of a Right Triangular Pyramid Reentry Configuration

An investigation of the low-speed static stability and control characteristics of a model of a right triangular pyramid reentry configuration has been made in the Langley free-flight tunnel. The investigation showed that the model had generally satisfactory longitudinal and lateral static stability characteristics. The maximum lift-drag ratio was increased from about 3 to 5 by boattailing the base of the model.

Paulson, John W.↗
NASA NTRS1953

Low-Speed Longitudinal Stability Characteristics of a 1/6-Scale Model of the Republic XF-84H Airplane with the Propeller Operating

A low-speed investigation was made of a 1/6-scale model of the Republic XF-84H airplane. The model had a single tractor propeller and a 40deg swept wing of aspect ratio 3.45. This investigation was undertaken to provide information on the effects of propeller operation on longitudinal stability characteristics for the XF -84H airplane and to provide an indication of slipstream effects that might be encountered on similar swept-wing configurations. Effects of propeller operation were generally destabilizing for all conditions investigated; however, the over-all stability characteristics with power on were greatly dependent on the power-off characteristics. With flaps and slats retracted, longitudinal instability was present at moderate angles of attack both with the propeller off and with power on. The longitudinal stability with flaps and slats deflected, which was satisfactory without power, was decreased by propeller operation, but no marked pitch-up tendency was indicated. Significant improvement in the power-on stability with flaps retracted was achieved by use of either a wing fence at 75 percent semispan, a leading-edge chord-extension from 65 to 94 percent semispan, or a raised horizontal tail located 65 percent semispan above the thrust line.

Sleeman, William C.↗