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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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12 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1950

Two-dimensional symmetrical inlets with external compression

The purpose of inlets like, for instance, those of air-cooled radiators and scoops is to take a certain air quantity out of the free stream and to partly convert the free-stream velocity into pressure. In the extreme case this pressure conversion may occur either entirely in the interior of the inlet (inlet with internal compression) or entirely in the free stream ahead of the inlet (inlet with external compression). In this report a theory for two-dimensional inlets with external compression is developed and illustrated by numerical examples. Intermediary forms between inlets with internal and external compression which can be derived from the latter are briefly discussed.

FLOW - DIFFUSERS↗
NASA NTRS1952

Performance of Air Inlets at Transonic and Low Supersonic Speeds

A general discussion of the air-inlet problem is presented. Recently obtained drag and pressure-recovery data for transonic-type nose, scoop, and wing-root inlets are summarized. Preliminary results concerning the performance of the sharp-edged supersonic-type inlets at transonic and subsonic speeds also are given.

Nichols, Mark R↗
NASA NTRS1947

Wind Tunnel Development of Means to Alleviate Buffeting of the North American XP-82 Airplane at High Speeds

This report presents the results of wind-tunnel tests of a 0.22-scale model of the North American XP-82 airplane with several modifications designed to reduce the buffeting of the airplane. The effects of various modifications on the air flow over the model are shown by means of photographs of tufts. The drag, lift, and pitching-moment coefficients of the model with several of the modifications are shown. The result indicate that, by reflexing the trailing edge of the center section of the wing and modifying the radiator air-scoop gutter and the inboard lower-surface wing fillets, the start of buffeting can be delayed from a Mach number of 0.70 to 0.775, and that the diving tendency of the airplane would be eliminated up to a Mach number of 0.80.

Anderson, Joseph L.↗
NASA NTRS1939

Pressure Distribution on the Fuselage of a Midwing Airplane Model at High Speeds

The pressure distribution on the fuselage of a midwing airplane model was measured in the NACA 8-foot high speed wind tunnel at speeds from 140 to 440 miles per hour for lift coefficients ranging from -0.2 to 1.0. The primary purpose of the tests was to provide data showing the air pressures on various parts of the fuselage for use in structural design. The data may also be used for the design of scoops and vents. The results show that the highest negative pressures occurred near the wing and were more dependent on the wing than on the fuselage. At high speeds, the magnitude of the pressure coefficients as predicted from pressure coefficients determined experimentally at low speeds by application of the theoretical factor 1/(square root)1-M(exp 2) (where M is the ratio of the air speed to the speed of sound in air) may misrepresent the actual conditions. At the points where the maximum negative pressures ocurred, however, the variation of the pressure coefficients was in good agreement with the theoretical factor, indicating that this factor may afford satisfactory predictions of critical speed, at least for fuselages similar to the shape tested.

Delano, James B.↗
NASA NTRS1942

Investigation of Diving Moments of a Pursuit Airplane in the Ames 16-Foot High Speed Wind Tunnel

A pursuit type airplane encountered severe diving moments in high-speed dives which make recovery difficult. For the purpose of investigating these diving moments and finding means for their reduction, a 1/6-scale model of the airplane was tested in the 16-foot high-speed wind tunnel at Ames Aeronautical Laboratory. The test results indicate that up to a Mach number of at least 0.75, the limit of the tests, the dive-recovery difficulties can be alleviated and the longitudinal maneuverability improved by the substitution of a long symmetrical fuselage for the standard fuselage.

MACH NUMBER↗
NASA NTRS1942

Preliminary Wind-Tunnel Tests of the Effect of Nacelles on the Characteristics of a Twin-Engine Bomber Model with Low-Drag Wing, Special Report

Tests were made in the NACA 19-foot pressure tunnel of a simplified twin-engine bomber model with an NACA low-drag wing primarily to obtain an indication of the effects of engine nacelles on the characteristics of the model both with and without simple split trailing-edge flaps. Nacelles with conventional-type cowlings representative of those used on an existing high-performance airplane and with NACA high-speed type E cowlings were tested. The tests were made without propeller slipstream. The aerodynamic effects of adding the nacelles to the low-drag wing were similar to the effects commonly obtained by adding similar nacelles to conventional wings. The maximum lift coefficient without flaps was slightly increased, but the increment in maximum lift due to deflecting the flaps was somewhat decreased. The stalling characteristics were improved by the presence of the nacelles. Addition of the nacelles had a destabilizing effect on the pitching moments, as is usual for nacelles that project forward of the wing. The drag increments due to the nacelles were of the usual order of magnitude, with the increment due to the nacelles with NACA type E cowlings approximately one-third less than that of the nacelles with conventional cowlings with built-in air scoops.

Wenzinger, Carl J.↗
NASA NTRS1944

Flight Tests of the Effect of Several Modifications on the Maximum Speed of the P-63A Airplane

Presented herein are the results of flight tests conducted to obtain the effect on maximum speed of several modifications to the P-63A airplane. These modifications made to the P-63A airplane as a result of previous flight and full-scale-tunnel tests increased the maximum speed of the airplane by 6 miles per hour. About one-half the increase is attributed to a reduction in drag and the remainder to increased ram at the carburetor entrance. The increase in ram of approximately 0.24 qc was obtained through modifications to the carburetor-scoop entrance and duct. The auxiliary supercharger is hydraulically coupled to the engine in such a way that the speed of the supercharger is regulated by absolute carburetor total pressure. This regulation is set so that full coupling is not reached until the airplane is well above full-throttle altitude. The action of the increased ram in reducing the speed of the auxiliary supercharger in the altitude range just above full-throttle altitude prevented a further speed increase of approximately 2 miles per hour from accompanying the increase in ram. Also, if the· auxiliary supercharger control could be rearranged to permit the maximum supercharger pressure ratio to be obtained at the full-throttle altitude, the speed in either the original or the modified configuration would be increased 5 miles per hour above that actually measured. The pressure recovery on the face of the prestone and oil radiators in the high-speed flight conditions was increased by an average of 14 percent of free-stream impact pressure as a result of the modifications made to the wing duct inlets.

Thomas J Voglewede↗