Flight and ground investigations have been made to compare an exhaust-ejector installation with a standard exhaust-collector-ring installation on air-cooled aircraft engines in a twin-engine airplane. The ground investigation allowed that, whereas the standard engine would have overheated above 600 horsepower, the engine with exhaust ejectors cooled at take-off operating conditions at zero ram. The exhaust ejectors provided as much cooling with cowl flaps closed as the conventional cowl flaps induced when full open at low airspeeds. The propulsive thrust of the exhaust-ejector installation was calculated to be slightly less than the thrust of the collector-ring-installation.

"A 1/12-scale model of a horizontal tail of a fighter airplane was tested through the transonic speeds in the high-speed flow over an airplane wing, the surface of which served as a reflection plane for the model. Measurements of lift, elevator-hinge moment, angle of attack, and elevator angle were made in the Mach number range from 0.75 to 1.04 for elevator deflections ranging from 10 degrees to minus 10 degrees, and for angles of attack of minus 1.2 degrees, 0.4 degrees, and 3.4 degrees. The equipment used to measure the hinge moments of the model proved to be unsatisfactory, and for this reason the hinge-moment data are considered to be only qualitative" (p. 1).

Report discussing an investigation to determine the effects of sweepback and low aspect ratio on the aerodynamic characteristics of a wing at high subsonic Mach numbers. Tests were performed at aspect ratios of 2, 3, and 5 and sweepback angles of 0, 30, and 45 degrees. Generally, sweepback and low aspect ratio were found to both delay and lessen the effects of compressibility.

Report presenting the results of flight testing to determine the zero-lift drag of an NACA 65-009 airfoil at a specified aspect ratio. The results are compared to previous testing of unswept and swept-back arrangements. The swept-forward and swept-back airfoils were found to produce lower values of zero-drag lift than the unswept airfoil.

Report discussing the results of flight tests to determine the drag at zero lift of a swept-back wing of inverse taper using an NACA 65-009 airfoil. The data was compared to untapered wings with a similar degree of sweepback. The tapered wing was found to have a lower drag coefficient than the 34-degree swept-back untapered wing but a higher drag coefficient than the 45-degree swept-back untapered wing.

Report discussing testing to determine the drag characteristics at zero lift of a wing with a circular-arc airfoil section with a maximum thickness of 9 percent chord. The results were compared to previous testing on an NACA 65-009 airfoil. It was found that the NACA airfoil had lower drag coefficients than the circular-arc airfoil tested in this experiment.

Tests to evaluate the effect of a conical windshield on the drag of a bluff body at supersonic speeds were performed for the following configurations: a sharp nose fuselage with stabilizing fins,a blunt nose fuselage with a hemispherical shape, and a blunt nose fuselage with a conical point. Results of the drag coefficient are described at Mach 1.0 and the greatest Mach number of 1.37.

Report presenting tests to determine the effects of sweepback angle and aspect ratio on the drag of an NACA 65-009 airfoil at supersonic speeds. The results indicated that for the range of Mach numbers investigated, increasing the sweepback angle and decreasing the aspect ratio reduced the value of the wing drag coefficient.

Flight tests were conducted to determine the effect of length of a conical windshield on the drag of a bluff body moving at supersonic speeds. A comparison is made between results obtained and results of previous drag tests of body-windshield combinations.The effect of increasing the length of the windshield is discussed.

Report presenting the results of tests to determine the effect of taper on the zero-lift drag of wings of constant exposed aspect ratio at low supersonic speeds. Findings indicated that maximum thickness, leading-edge, and trailing-edge sweep are all important in determining the drag coefficient of a tapered wing.

Report presenting an investigation of the mechanism of interaction of compression shock with boundary layer. Shockless pressure distributions at supercritical Mach numbers were found to be accounted for by a marked thickening of the boundary layer for some distance ahead of a shock wave.

Report presenting an investigation of the low-speed characteristics of a 25-foot span triangular wing with an aspect ratio of 2. the airfoil section of the wing was a symmetrical double wedge with 5-percent maximum thickness at 20-percent chord. Results regarding the longitudinal characteristics, lateral characteristics, and directional characteristics are provided.

Report presenting a study of the characteristics of a large-scale triangular wing to include the effects of section modifications. The wing in this report is the same as the one in the previous report but features various degrees of rounding of the wing leading edge and wing maximum thickness rather than having sharp edges. Results regarding the effects of airfoil section modifications, visible trailing vortices, and surveys in the extended chord plane are provided.

"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" (p. 1).

"A solution is presented for the coupled modes and frequencies of swept wings mounted on a fuselage. The energy method is used in conjunction with power series to obtain the characteristic equations for both symmetrical and asymmetrical vibration. A numerical example which is susceptible to exact solution is presented, and the results for the exact solution and the solution presented in this paper show excellent agreement" (p. 1).

"This report contains the flight-test results of the lateral and directional-stability and control phase (including tests with wing-tip tanks) of a general flying-qualities investigation of the Lockheed P-80A airplane (Army No. 44-85099). These tests were conducted at indicated airspeeds up to 494 miles per hour (0.691 Mach number) at low altitude and up to 378 miles per hour (0.816 Mach number) at high altitude. These tests showed that the flying qualities of the airplane were for the most part in accordance with the requirements of the Army Air Forces Stability and Control Specifications" (p. 1).

This report contains the flight-test results of the stalling characteristics measured during the flying-qualities investigation of the Lockheed P-8OA airplane (Army No. 44-85099). The tests were conducted in straight and turning flight with and without wing-tip tanks. These tests showed satisfactory stalling characteristics and adequate stall warning for all configurations and conditions tested.

This report contains the flight-test results of the longitudinal-stability and -control phase of a general flying qualities investigation of the Lockheed P-80A airplane (Army No. 44-85099). The tests were conducted at indicated airspeeds up to 530 miles per hour (0.76 Mach number) at low altitude and up to 350 miles per hour (0.82) Mach number) at high altitude. These tests showed that the flying qualities of the airplane were in accordance with the requirements of the Army Air Forces Stability and Control Specification except for excessive elevator control forces in maneuvering flight and the inadequacy of the longitudinal trimming control at low airspeeds.

"An analysis of the effects of compressibility on the longitudinal stability, control, and trim of airplanes flying at high subsonic speeds and a discussion of the causes of and the means for lessening or preventing the diving tendency are presented. Wind-tunnel results for Mach numbers up to 0.90 are included for purposes of illustration and cover several investigations of longitudinal stability and control, airfoil characteristics, dive-recovery aids, and elevator characteristics. Methods are indicated for compensating for the undesirable control tendencies results from the characteristics of the wing at supercritical speeds by the appropriate choice of elevator contour" (p. 1).

Report presenting the results of testing in the transonic range of four flutter airfoils attached to a freely falling body. Failures of the airfoils were metered and recorded in order to determine the Mach numbers and altitudes of failure.

"The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of the Douglas XSB2D-1 airplane. Comparisons are made between the root bending moment and section torsional moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending moment coefficients but considerable disagreement for the torsional moment coefficients, the measured moments being greater than the analytical moments. The effects of Mach number on both the bending moment and torsional moment coefficients were small" (p. 1).

"The tests reported herein were made for the purpose of determining the high-speed load distribution on the wing of a 3/16 scale model of a scout-bomber airplane. Comparisons are made between the root bending-moment and section torsional-moment coefficients as obtained experimentally and derived analytically. The results show good correlation for the bending-moment coefficients but considerable disagreement for the torsional-moment coefficients" (p. 1).

Report presenting an investigation in the propeller-research tunnel to develop wing-leading-edge inlets for locations between the inboard and outboard nacelles on each wing of a four-engine airplane. Testing was performed on the basic wing and original inlet as well as NACA-developed inlets for two versions of the airplane.

Report presenting the air-flow behavior over the wing of an XP-51 airplane including photographs of tufts attached to the wing surface and chordwise pressure distributions. A comparison of tuft studies from flight results are compared with results from wind-tunnel testing. Three types of flow were observed: steady flow, unsteady flow, and break-away flow are provided.