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Results for “Propeller Aerodynamics”

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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Acoustic and aerodynamic study of a pusher-propeller aircraft model

An aerodynamic and acoustic study was made of a pusher-propeller aircraft model in the NASA-Ames 7 x 10 ft Wind Tunnel. The test section was changed to operate as an open jet. The 591 mm diameter unswept propeller was operated alone and in the wake of three empennages: an I tail, Y tail, and a V tail. The radiated noise and detailed wake properties were measured. Results indicate that the unsteady blade loading caused by the blade interactions with the wake mean velocity distribution had a strong effect on the harmonics of blade passage noise. The blade passage harmonics above the first were substantially increased in all horizontal directions by the empennage/propeller interaction. Directivity in the plane of the propeller was maximum perpendicular to the blade surface. Increasing the tail loading caused the propeller harmonics to increase 3 to 5 dB for an empennage/propeller spacing of 0.38 mean empennage chords. The interaction noise became weak as empennage propeller spacing was increased beyond 1.0 mean empennage chord lengths. Unlike the mean wake deficit, the wake turbulence had only a small effect on the propeller noise, that effect being a small increase in the broadband noise.

Soderman, Paul T.↗
NASA NTRS1991

Flow interaction and noise from a counter rotating propeller

The aerodynamic interaction between the forward and rear rotors in a counter rotating propeller (CRP) system, has been examined using a conditional sampling technique applied to three-dimensional thermal anemometer data. The technique effectively freezes the rotors in any desired relative position and provides the inter-rotor flow field. Axial, radial and circumferential mean flow between rotors is shown relative to the 'fixed' forward rotor for various 'fixed' aft rotor positions. Acoustic far field noise data have also been collected for the same operating conditions. The acoustic results are presented with emphasis on the blade passing frequencies and interaction tone of the CRP.

Chung, Jin-Deog↗
NASA NTRS1983

Contribution to the aerodynamic study of wings and propellers

Various problems regarding the aerodynamics of lifting wings are solved. Two methods are proposed for replacing the wing, both involving "viscous" edge vortices. the applications give results which agree well with experiments. Two new methods are also proposed for calculating propellers based on the vortex model consisting of an edge vortex and a "viscous" hub vortex.

Menard, M.↗
NASA NTRS1942

The Characteristics of Two Model Six-blade Counterrotating Pusher Propellers of Conventional and Improved Aerodynamic Design

Two airfoil plans were used for propeller blades. One is modified Clark Y section designed for structural reliability and the second an NACA 16 airfoil section designed to produce minimum aerodynamic losses. At low air speeds, the propeller designed for aerodynamic effects showed a gain of from 1.5 to 4.0 percent in propulsive efficiency over the conventional type depending on the pitch. Because of the numerous variables involved, the effect of each one on the aerodynamic characteristics of the propellers could not be isolated.

PROPELLERS - PROPULSIVE EFFICIENCY↗
NASA NTRS1992

Aerodynamic characteristics of a propeller powered high lift semispan wing

An experimental investigation was conducted on the engine/airframe integration aerodynamics for potential high-lift aircraft configurations. The model consisted of a semispan wing with a double-isolated flap system and a Krueger leading edge device. The advanced propeller and the powered nacelle were tested and aerodynamic characteristics of the combined system are presented. It was found that the lift coefficient of the powered wing could be increased by the propeller slipstream when the rotational speed was increased and high-lift devices were deployed. Moving the nacelle/propeller closer to the wing in the vertical direction indicated higher lift augmentation than a shift in the longitudinal direction. A pitch-down nacelle inclination enhanced the lift performance of the system much better than vertical and horizontal variation of the nacelle locations and showed that the powered wing can sustain higher angles of attack near maximum lift performance.

Takallu, M. A.↗
NASA NTRS1994

Aerodynamic characteristics of a propeller-powered high-lift semispan wing

A small-scale semispan high-lift wing-flap system equipped under the wing with a turboprop engine assembly was tested in the LaRC 14- by 22-Foot Subsonic Tunnel. Experimental data were obtained for various propeller rotational speeds, nacelle locations, and nacelle inclinations. To isolate the effects of the high lift system, data were obtained with and without the flaps and leading-edge device. The effects of the propeller slipstream on the overall longitudinal aerodynamic characteristics of the wing-propeller assembly were examined. Test results indicated that the lift coefficient of the wing could be increased by the propeller slipstream when the rotational speed was increased and high-lift devices were deployed. Decreasing the nacelle inclination (increased pitch down) enhanced the lift performance of the system much more than varying the vertical or horizontal location of the nacelle. Furthermore, decreasing the nacelle inclination led to higher lift curve slope values, which indicated that the powered wing could sustain higher angles of attack near maximum lift performance. Any lift augmentation was accompanied by a drag penalty due to the increased wing lift.

Gentry, Garl L., Jr.↗
NASA NTRS1938

The Aerodynamic Characteristics of Four Full-Scale Propellers Having Different Plan Forms

Tests were made of four propellers, with diameters of 10 feet, having different blade plan forms. One propeller (Navy design no. 5868-r6) was of the usual present-day type and was used as a basis of comparison for the other three, which had unusual plan forms distinguished by the inward (toward the hub) location of the sections having the greatest blade width. It was found that propellers with points of maximum blade width occurring closer to the hub than on the present-day type of blade had higher peak efficiencies but lower take-off efficiencies. This results was found true for a "clean" liquid-cooled engine installation. It appears that some modification could be made to present plan forms which would produce propellers having more satisfactory aerodynamic qualities. The propellers with the inward location of the points of maximum blade width had lower thrust and power coefficients and stalled earlier than the present-day type.

Hartman, Edwin P↗
NASA NTRS1971

Aerodynamic characteristics of the Grumman H-33 orbiter mated to a three segment solid propellant booster

Experimental aerodynamic investigations were conducted on a .003366-scale model of the Grumman space shuttle configuration mounted to a three (3) segmented solid propellant booster. These tests were conducted in the MSFC 14-inch trisonic wind tunnel over a Mach number range of 0.6 to 4.96. The purpose of the test was to determine the aerodynamic characteristics of this configuration. Aerodynamic data was taken over a nominal angle of attack and angle of sideslip of -10 degrees to 10 degrees at zero degrees beta and alpha respectively. In addition, data was obtained for the H-33 orbiter alone to supplement data from TWT 502 and TWT 503.

Sims, F.↗
NASA NTRS1984

Stability and control results for advanced turboprop aft-mount installations

An experimental investigation was recently conducted in the NASA-Langley Research Center 4- by 7-Meter Tunnel to explore the effects of aft-mounted advanced turboprop installations on the low-speed stability and control characteristics of a representative transport aircraft configuration. For the conditions investigated, the experimental results indicate that the longitudinal and directional stability of the configuration was not adversely affected by aft-pylon-mounted single-rotation tractor or counter-rotation pusher propeller installations. The results indicate that for the single-rotation tractor configuration the propeller induced aerodynamics are dominated by the interaction of the propeller slipsteam with the pylon, and that the propeller contribution to the stability characteristics for the counter-rotating pusher configuration is dominated by propeller normal forces. The longitudinal and directional control effectiveness, engine-out characteristics, and ground effects are also presented.

Coe, P. L., Jr.↗
NASA NTRS1985

Theoretical analysis of linearized acoustics and aerodynamics of advanced supersonic propellers

The derivation of a formula for prediction of the noise of supersonic propellers using time domain analysis is presented. This formula is a solution of the Ffowcs Williams-Hawkings equation and does not have the Doppler singularity of some other formulations. The result presented involves some surface integrals over the blade and line integrals over the leading and trailing edges. The blade geometry, motion and surface pressure are needed for noise calculation. To obtain the blade surface pressure, the observer is moved onto the blade surface and a linear singular integral equation is derived which can be solved numerically. Two examples of acoustic calculations using a computer program are currently under development.

Farassat, F.↗
NASA NTRS1952

Calculation of aerodynamic forces on a propeller in pitch or yaw

An analysis was made to determine the applicability of existing propeller theory and the theory of oscillating airfoils to the problem of determining the magnitude of the forces on propellers in pitch or yaw. Strip calculations using compressible airfoil characteristics were first made as though steady-state conditions existed successively at several blade positions of the propeller blades during one revolution. A theory of oscillating airfoils in pulsating incompressible potential flow was then considered from which it was possible to determine factors which would modify the steady-state forces.

PROPELLERS - PITCH AND YAW↗
NASA NTRS1961

Aerodynamic Characteristics of Propeller-Driven VTOL Aircraft

This paper discusses the two major configurations that are usually considered for achieving VTOL while keeping the fuselage essentially horizontal - that is, the tilt-wing and the deflected-slipstream configurations. Because of the high turning losses incurred by deflected-slipstream configurations in hovering and because of the wing-stalling problem of the pure tilt-wing configurations during the transition, it appears that a combination of the two principles should be used. This tilt-wing and flap configuration should make use of a programmed extensible-chord slotted flap together with a leading-edge high-lift device in order to avoid the performance and handling qualities problems associated with wing stalling during the transition while keeping the wing area as low as possible for efficiency in cruising flight.

Kirby, Robert H.↗