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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1976

Wind-tunnel tests of a 1/4 scale model of the Bell XS-1 transonic airplane. 1: Longitudinal stability and control characteristics

A 1/4 scale model of the Bell XS-1 transonic aircraft was tested in the Langley 300 mile-per-hour 7 by 10 foot tunnel to determine its low speed longitudinal stability and control characteristics. Pertinent longitudinal flying qualities expected of the XS-1 research airplane were estimated from the results of these tests including the effects of compressibility likely to be encountered at speeds below the force break. It appears that the static longitudinal stability and elevator control power will be adequate, but that the elevator control force gradient in steady flight will be undesirably low for all configurations. It is suggested that a centering spring be incorporated in the elevator control system of the airplane in order to increase the control force gradient in steady flight and in maneuvers.

Donlan, C. J.↗
NASA NTRS1990

Low-speed wind tunnel investigation of the static stability and control characteristics of an advanced turboprop configuration with the propellers placed over the tail

An exploratory wind tunnel investigation was performed in the 30 x 60 foot wind tunnel to determine the low speed static stability and control characteristics into the deep stall regime of an advanced turboprop aircraft with the propellers located over the horizontal tail. By this arrangement, the horizontal tail could potentially provide acoustic shielding to reduce the high community noise caused by the propeller blades. The current configuration was a generic turboprop model equipped with 1 foot diameter single rotating eight bladed propellers that were designed for efficient cruise operation at a Mach number of 0.8. The data presented is static force data. The effects of power on the configuration characteristics were generally favorable. An arrangement with the propellers rotating with the outboard blades moving down was found to have significantly higher installed thrust than an arrangement with the propellers rotating with the inboard blades moving down. The primary unfavorable effect was a large pitch trim change which occurred with power, but the trim change could be minimized with a proper configuration design.

Rhodes, Graham Scott↗
NASA NTRS1948

Longitudinal-stability Investigation of High-lift and Stall-control Devices on a 52 Degree Sweptback Wing with and Without Fuselage and Horizontal Tail at a Reynolds Number of 6.8 x 10(exp 6).

Contains low-speed longitudinal stability characteristics of a 52 degree sweptback wing of aspect ratio 2.88, taper ratio 0.625, and NACA 64 (sub 1)-112 airfoil sections normal to the 0.282-chord line, in combination with split flaps, leading-edge flaps, and upper-surface fences. Low-wing and midwing-fuselage aerodynamic characteristics are presented with and without a horizontal tail at various vertical locations. Tests were conducted at a Reynolds number of 6.8 x 10(exp 6).

STABILITY, LONGITUDINAL - STATIC↗
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 NTRS1946

Comparison of Wind-Tunnel and Flight Measurements of Stability and Control Characteristics of a Douglas A-26 Airplane

Tests in Langley pressure tunnel of model XA-26 bomber were compared with those of A-26B (twin-engine attack bomber) and showed that static longitudinal stability, indicated by elevator-fixed neutral points, and variation of elevator deflection in straight and turning flight were good. Airplane possessed improved stability at low speeds which was attributed to pronounced stalling at root of production wing. At rudder-force reversal at speeds higher than those in flight tests, agreement in rudder-fixed and rudder-free static directional stability was good. Hinge moment obtained at zero sideslip was satisfactory for determining aileron forces in sideslip.

SIDESLIPPING - DOUGLAS A-26↗
NASA NTRS1960

Low-Speed Measurements of Static and Oscillatory Lateral Stability Derivatives of a 1/5-scale Model of a Jet-Powered Vertical-Attitude VTOL Research Airplane

An investigation has been made in the Langley free-flight tunnel to determine the low-speed static lateral stability characteristics and the rolling, yawing, and sideslipping dynamic stability derivatives of a 1/5-scale model of a jet-powered vertical-attitude VTOL research airplane. The results of this investigation are presented herein without analysis.

Shanks, Robert E.↗
NASA NTRS1978

Supersonic transport

An aircraft of supersonic transport configuration is described, featuring thrust vectoring in conjunction with wing apex segments used as canard surfaces during takeoff, landing, and low-speed flight. The angle of incidence of the wing apex segments, when the segments were functioning as canard surfaces, was variable with respect to the aircraft angle of attack. The wing apex segments furthermore formed a portion of the main wing panel swept leading edge when not functioning as canard surfaces. The combination of thrust vectoring and deployable wing apex segments resulted in increased aircraft range and improved low speed longitudinal stability while providing acceptable takeoff length capabilities.

Coe, P. L., Jr.↗
NASA NTRS1980

Low-speed aerodynamic characteristics of a highly swept arrow wing configuration with several deflected leading edge concepts

The effectiveness of leading edge concepts for minimizing or controlling leading edge flow separation was studied. Emphasis was placed on low speed performance, stability, and control characteristics of configurations with highly swept wings. Simple deflection of the leading edge, a variable camber leading edge system, and a leading edge vortex flow system were among the concepts studied. The data are presented without analysis.

Gentry, G. L., Jr.↗
NASA NTRS1980

Leading-edge 'Vortex Flaps' for enhanced subsonic aerodynamics of slender wings

The 'Vortex Flap' is a novel concept aimed at reducing the lift-dependent drag due to leading-edge flow separation on highly swept, slender wings at high angles of attack. The suction effect of coiled vortices generated via controlled separation over leading-edge flap surfaces is utilized to produce an aerodynamic thrust component. This principle was verified through wind-tunnel experiments on 74-deg and 60-deg delta wings and a supersonic-cruise slender wing aircraft configuration. Adaptation of the vortex-flap for augmentation of roll-control on the 74-deg delta at high angles of attack also was demonstrated. Selected results are presented in this paper to indicate the potential of the vortex flap concept to enhance the low-speed performance, stability and control of slender wing aircraft.

Rao, D. M.↗
NASA NTRS1923

Control of airplanes at low speeds

Loss of control over the orientation of an airplane as the incidence approaches and enters the region of stalled flight is a prolific cause of serious accidents. This report discusses methods of landing at slow speeds approaching stall.

CONTROL AT LOW SPEEDS↗