Tests were made in 8-ft high-speed wind tunnel to determine the drag reduction possible by eliminating the barrel jacket of a protruding 50-caliber aircraft gun. It was found that the drag of a standard aircraft gun protruding into the air stream at right angles to the flow can be reduced by 23% by discarding the barrel jacket. At 300 mph and sea-level conditions, this amounts to a decrease in drag of from 83 to 64 pounds. A rough surface finish on the barrel was found to have no adverse effects on the drag of the barrel, the drag being actually less at high Mach Numbers.

Report presenting testing in the full-scale tunnel to provide data for estimating the longitudinal stability and control characteristics of the Curtis XP-55 airplane. Testing included lift, drag, pitching-moment, hinge-moment, and elevator pressure measurements for various combinations of angle of attack, elevator deflection, and elevator tab settings. The results of the force tests and some correlation of the results of the force tests and the pressure measurements are presented in the report.

Report presenting tests of representative models of flying boat hulls to determine the resistance at low speeds. Results regarding the effect of load coefficients, resistance coefficients, and towing and drifting calculations are provided.

Supplement using data from a previous report to show the cargo that can be carried at various ranges, pounds of cargo that can be carried per pound of fuel, and other graphs to simplify the problem of determining which cargo can be carried at any range. The assumptions, parameters, and equations from the original report are carried over in the supplement.

Report presenting an investigation of the effect of spray strips on the low-speed spray characteristics on a model of the Consolidated PB2Y-3 flying boat. The main purpose of the investigation was to determine what form the strips should be fitted to give the most practicable answer to the problem of controlling the spray at heavy loads.

Report presenting tests in the full-scale tunnel to determine the longitudinal- and lateral-stability and control characteristics of a scale model of the XP-69 airplane. The data include measurements of the forces and moments on the model at various angles of attack and angles of yaw. The effects of elevator, rudder, and aileron deflection on control-surface effectiveness and on hinge moments were determined.

Report presenting testing in the two-dimensional low-turbulence pressure tunnel and the two-dimensional low-turbulence tunnel of two models made by the Consolidated Aircraft Corporation, one of the outboard section and one of the inboard section.

Report presenting the results of flight investigations showing that a beveled trailing-edge aileron gives as low or a lower profile drag than a contour aileron. Section profile drag and lift coefficients with two different types of ailerons were obtained at 3 different Reynolds numbers.

Report presenting power-off wind tunnel tests of a scale model of a twin-engine cargo airplane equipped with amphibious floats. Longitudinal and lateral stability and control characteristics were investigated for three flap positions.

Report presenting stability, maximum lift, and high-speed tests of an observation airplane fitted with Maxwell leading-edge slots. The static and dynamic longitudinal and lateral stability was generally satisfactory and not affected much by the slots.

Report presenting testing of the flutter characteristics of the SB2U-2 airplane. The secondary purpose of the test, which ended up being the primary purpose, was to study the behavior of the airplane just below the flutter speed. Results regarding flutter amplitude, frequencies, and energy-absorbing qualities are provided.

Report presenting an investigation of the effect of wing loading, power loading, and aspect ratio on the performance of pursuit airplanes. The study is based on data combined from specifications, wind-tunnel, and flight tests of various airplanes and presented in graphs.

Report presenting tests on a scale model of a four-engine cargo airplane, which was tested in the high-speed wind tunnel. The high-speed characteristics of the airplane, particularly the longitudinal stability and control in dives were investigated. Test results indicated that no important changes in longitudinal stability or controllability occurred until the speed exceeded the predicted maximum level-flight speed by more than 38 percent.

"Tests of a tailless pursuit airplane model at the Ames Aeronautical Laboratory have shown that in conditions corresponding to level flight at a Mach number less than 0.7 and at an altitude under 35,000 feet, no serious compressibility effects occurred and that no sudden adverse diving moments were encountered up to a Mach number of 0.74, the maximum speed of the tests. However, there were indications that the elevons might lose their effectiveness for longitudinal control during a pull-out from a steep dive" (p. 1).

Report presenting a flight investigation of the flying qualities and stalling characteristics of a North American XP-51 airplane. The short-period longitudinal oscillation disappeared within one cycle in all conditions tested. Requirements for satisfactory stalling characteristics were met in all respects except for stall warning.

Report presenting observations made of the air flow around a Martin PBM-3 flying boat. The observations are part of an analysis to aid in the determination of possible methods of reducing the air drag of the airplane. The behavior of the tufts on the hull and tip floats at various airplane speeds by still and moving pictures taken from an accompanying airplane.

"The following surveys on the vibration response of the P-40 rudder and fin-rudder assembly were conducted during the fall of 1942 for the purpose of obtaining information on the flutter characteristics of high-speed airplanes of known performance. The tests on the rudder alone were made with the rudder suspended in a floating condition; the tests on the fin-rudder unit were made with the fin rigidly fastened to a concrete base" (p. 1). A variety of figures and diagrams for the assembly are provided.

Report presenting a study of the flutter characteristics of the P-47 tail assembly, which included replacing the original fabric-covered rudder with a metal-covered rudder and reinforcing the fin. Figures are provided for different configurations and the cycles per second under the same conditions are provided.

Report discussing testing on a model of a pursuit type airplane to determine the effect of several devices that may be applied to improve the high-speed pitching-moment characteristics. Auxiliary flaps, a controllable stabilizer, and a change in wing contour were all found to help increase the amount of control when recovering from high-speed dives.

Report presenting force tests and measurements of the pressure distribution over the elevator and forward part of the fuselage on a flying model of the Curtiss XP-55 airplane in the full-scale tunnel. The results of the elevator pressure measurements are given in this paper. Results regarding chordwise pressure distributions, span-load distribution, and normal-force coefficients are provided.

Report presenting experimental data on the distribution coefficients of technical xylidines for the system gasoline-water. The distribution coefficient is defined as the ratio of the concentration of xylidines in the gasoline layer to that in the water layer. Results regarding the effect of concentration of xylidines, effect of aromatic content of fuel, effect of sea water, and effect of temperature are provided.

Report presenting an investigation to determine the loci of possible positions of a heavy bomber in space following a 12-second interval.

Report presenting testing to determine the low-temperature solubility of technical xylidines in aviation gasoline. Testing included measuring the cloud point, or incipient separation temperature, at several concentrations of technical xylidines in a 65-octane-number clear gasoline without aromatics and with aromatics added in various percentages up to 15 percent by volume and a grade 130, specification AN-F-28, amendment 2, gasoline.

Report presenting a study of the installation of 1800-horsepower engines in the PB2Y-3 airplane in place of the current 1200-horsepower engines. Stability and spray tests were made to determine the performance of the model on the water when tested at both the present and projected conditions of gross load and engine power. Results regarding aerodynamic tests and hydrodynamic tests are provided.