Report presenting the results of tests of a circular fuselage with various combinations of tail lengths and vertical tail surfaces with and without the horizontal tail surface in the 6- by 6-foot test section of the stability tunnel in the form of diagrams of variation of coefficients of lateral force and yawing moment with angle of yaw and angle of attack.

Report presenting testing of preformed copper fins which were furnace-brazed to a steel-cylinder barrel. The barrel was electrically heated and blower-cooled to determine heat overall heat-transfer coefficient. Information regarding potential future adaptations of the fins are provided.

Report presenting an investigation of the effect of compressibility on the drag of a Bell P-39N-1 airplane in flight as part of a drag study on several high-speed airplanes for a range of Mach numbers.

Report discusses an analysis and preliminary design of a control linkage that varies automatically with dynamic pressure. The advantages of the device, including greater lateral control than a fixed control linkage without additional aerodynamic balance, are detailed. The effect of variable linkage on lateral-control characteristics is also described.

Report discussing several types of jet-exit designs, including normal, beveled, and unsymmetrical shapes, and their effect on the stability characteristics of the aircraft. No deviation of the jet center line from its exposed path is likely to be obtained if a jet exist is used that is normal to the flow. Having a tilted or asymmetrical exit was found to adversely affect the stability of the aircraft.

Report presenting an investigation of the effects of propeller operation on pitching moments with particular reference to the effect of propeller forces, the field of flow in the slipstream, and the increments of lift on the wing and the tail. A procedure, directly applicable only to single-engine monoplanes without flaps, has been set up for predicting the effect of propeller operation on pitching moments as well.

Report discussing the changes in static longitudinal stability due to tilting the propeller axis of an SB2C-3 airplane downward. Tilting the propeller was found to be beneficial for stability, but only if the pilot was in a forward center-of-gravity position with a tilted engine. Installing a tilted engine reduced trim forces due to the changes in power up to 25 percent.

Report discusses the results of shear testing in which the heads of Du Pont explosive countersunk rivets were allowed to protrude above the skin surface before expansion and the protruding portions were removed after expansion. As the height of the rivet head above the skin increases, the tightness of the rivet was found to increase. The report concludes that it may be desirable to investigating filling an entire shank with an explosive charge in order to permit greater tolerances in the drilled hole diameter and still have consistently tight rivets.

The data presented have no bearing on performance characteristics of airplane, which were considered exceptionally good in previous tests. Some of the undesirable features of lateral and directional stability and control characteristics of the F-8 are listed. Directional stability, with rudder fixed, did not sufficiently restrict aileron yaw; rudder control was inadequate during take-off and landing, and was insufficient to fly airplane with one engine; in clean condition, power of ailerons was slightly below minimum value specified; it was difficult to trim airplane in rough air.

Report presenting the results of aerodynamic tests of seven-blade propellers which were considered as a possible arrangement to avoid vibration difficulties. Variations of relative blade angle and rotational speeds of the front and rear components of a six-blade dual-rotating propeller were also investigated.

Report presenting an investigation of the size and distribution of ice particles on the wings of aircraft and how they affect the aerodynamic characteristics. A simulated ice formation was generated from survey information received from aircraft pilots and was tested to determine the impact on the lift characteristics.

Report discussing the characteristics of the jet-motor air-intake duct system for a pursuit-type airplane with modifications to the duct system. Details of its effects on the Mach number, high pressure recovery, drag, and simplicity of the system are provided. Problems regarding the flow condition through the ducts and some potential modifications to prevent further issues are also described.

"Column and plate compressive strengths of extruded 14S-T aluminum alloy were determined both within and beyond the elastic range from tests of flat-end H-section columns and from local-instability tests of H-, Z-, and channel-section columns. These tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. The results are presented in the form of curves and charts that are suitable for use in the design and analysis of aircraft structures" (p. 1).

The results of this analysis indicate that isothermal pressure losses can be predicted analytically in the type of ducting system which may be broken down into the elementary forms of elbows, diffusers, and straight ducts for which pressure-loss data are published.

Report discusses the "effects of oil introduced into the combustion chamber and of oil-spray piston cooling on the knock-limited performance of aircraft engines" (from Summary). A CFR engine and Allison V-1710 cylinder were used to test the rate of oil consumption, knock, and knock-limited brake mean effective pressure.

Report presenting performance charts for gliders and twin-engine tow planes with different degrees of aerodynamic and structural refinement. The glider charts display the gliding angle, useful load, stalling speeds, power required for level flight at various speeds, and power required for level flight while climbing at various speeds. The tow-plane charts show the stalling speeds, power required for level flight at various speeds, and power required for level flight while climbing at various speeds.

Report presenting an investigation to determine the knock-limited performance in a full-scale aircraft-engine cylinder of leaded blends of 10 pure hydrocarbons and a base fuel.

Report presenting a method for predicting the amplitude and frequency, under certain simplifying conditions, of the hunting oscillations of an automatically controlled aircraft with lag in the control system or in response of the aircraft to the controls. Formulas are given expressing the response to a variation of signal in terms of response to a unit signal.

"An analysis was made to show the relative effectiveness of streamline external fuel tanks, a fuel tank in the form of a wing mounted in a biplane position, and auxiliary wing panels attached at the wing tips to increase the span as temporary means for increasing the range of a fighter-type airplane. Figures and charts for the various devices considered show the results of calculations of range, duration of flight, and take-off distance for both land-base and carrier operation. The results indicated that the wing-tip extensions were the most promising of the devices considered" (p. 1).

Report presenting the deceleration of air from supersonic velocities in channels. A normal shock in the diverging part of the diffuser is probably necessary for stable flow, and ways of minimizing the intensity of this shock have been developed.

Report discusses measurements of the relaxation time of steam and nitrogen due to their importance as turbine-working fluids. Additional calculations regarding different nozzle lengths are included.

Report presenting tests of a three-barrel pressure carburetor to determine the effect of nonuniformity of the air flow in the intake duct on the metering of the carburetor. Measurements were made in the air side of the metering system and in the carburetor barrels for a variety of flow distributions. Results regarding the metering pressure, altitude compensation, effect of throttle on the metering characteristics, and flow of air around the bends are provided

Report discussing a study of the heat-transfer processes in liquid-cooled engines, an equation that has been developed based on the testing, and additional tests on an Allison V-3420-11 engine to determine the accuracy of the equation and the cooling characteristics of the engine. The equation was found to predict heat rejection to a coolant with good accuracy.

"An investigation was made of the methods of supporting single-thickness specimens of aluminum-alloy sheet material in a fixture for determination of compressive stress-strain curves. The specimens were supported in the fixture by rollers, offset-grooved plates, opposite-grooved plates, flat brass plates, or flat wooden plates. The investigation also showed that the compression fixture, the specimen support, and the single-thickness specimens must be accurately made in order to obtain accurate stress-strain curves consistently" (p. 1).