Report discussing tests of a model of the XP-55 to determine which modifications would prevent trim at large positive and negative angles of attack. The model was found to not trim at flat attitudes if the large wing tips with an extension of the wing-tip trimmers and a large elevator are installed on the airplane.

Report discussing spin tests performed on a scale model of the Curtiss-Wright XP-55 airplane. A large elevator with increased deflections and large wing tips with extensions were installed to improve the longitudinal-trim characteristics. Information about the spins, attitude after rotation, and recommended technique for spin recovery is provided.

Report presenting a generalized drag curve providing an estimate for the drag rise due to compressibility as obtained from an analysis of wind-tunnel data of several airfoils, fuselages, nacelles, and windshields at speeds up to and above the wing critical speed. Results regarding drag characteristics and terminal-velocity calculation are provided.

Report presenting an investigation to determine the suitability and precision of a modified, routine-model, infrared spectrophotometer for analyzing binary and ternary mixtures of aircraft-fuel components. Analyses by means of infrared measurements are described for the following hydrocarbon mixtures: 12 known mixtures of 2,2,3-trimethylbutane (triptane) and cyclohexane, 4 known mixtures of triptane and benzene, and 4 known mixtures of triptane, cyclohexane, and benzene.

An investigation was conducted to determine the effect of a coolant solution of 25 percent ethyl alcohol, 25 percent methyl alcohol, and 50 percent water by volume and maximum-economy spark advance on knock-limited performance and fuel economy of a large air-cooled cylinder. The knock-limited performance of the cylinder at engine speeds of 2100 and 2500 rpm was determined for coolant-fuel ratios of 0.0, 0.2, and 0.4. The effect of water-alcohol injection on fuel economy was determined in constant charge-air flow tests. The tests were conducted at a spark advance of 20 deg B.T.C. and maximum-economy spark advance.

Report discusses the results of a study "of the requirements for the attainment of a straight-line trajectory for a preset guided missile in the presence of wind or target motion" (from Summary). Information about the straight-line trajectory, position of the launching airplane, straight-line collision course, and arrangement of the autopilot in the missile is provided. Recommendations are also made about the creation of a bombsight mounting for the pilot of the launching airplane in order to attain the desired straight-line collision course.

Report discusses the differences between the mean tangential velocity of the air leaving the blade tips of a centrifugal supercharger calculated by the conventional turbine equation and by an equation that uses the isentropic increase in total enthalpy. The velocities are compared to experimental values observed with three diffusers.

Report discussing a comparison between a centrifugal-flow-type turbojet engine with an adjustable-area exhaust nozzle and with a series of fixed-area nozzles of various throat diameters. The adjustable-area nozzle was found to be as efficient as the fixed-area nozzles in testing. Information about the corrected static thrust, fuel flow, and tail-pipe gas temperature for both types of nozzles is provided.

Report discussing an investigation to determine the effect of omitting some of the fuel constituents in AN-F-28 Amendment 2 fuel that are normally lost in flight on fuel-vapor loss. Removing the components was found to decrease the fuel-vapor loss and increase the critical altitudes.

Report discussing tests on three fuels in a 14-cylinder double-row radial air-cooled engine at different engine speeds, blower ratios, and spark settings.

"A comparison has been made in flight of the antiknock characteristics of 33-R fuel with that of 28-R and a triptane blend. The knock-limited performance of the three fuels - 33-R, a blend of 80 percent 28-R plus 20 percent triptane (leaded to 4.5 ml TEL/gal), and 28-R - was investigated in two modified 14-cylinder double-row radial air-cooled engines. Tests were conducted on the engines as installed in the left inboard nacelle of an airplane. A carburetor-air temperature of approximately 85 deg F was maintained" (p. 1).

Report discussing testing of 2-percent additions of seven aromatic amines on the knock-limited performance of 28-R fuel in a CFR engine. The most effective antiknock additives are described.

"As part of an investigation of the cooling characteristics of liquid-cooled engines, tests were conducted with an electrically heated single-tube heat exchanger to determine the heat-transfer characteristics of AN-E-2 ethylene glycol and other ethylene glycol-water mixtures. Similar tests were conducted with water and commercial butanol (n-butyl alcohol) for check purposes. The results of tests conducted at an approximately constant liquid-flow rate of 0.67 pound per second (Reynolds number, 14,500 to 112,500) indicate that at an average liquid temperature 200 degrees f, the heat-transfer coefficients obtained using water, nominal (by volume) 30 percent-70 percent and 70 percent-30 percent glycol-water mixtures are approximately 3.8, 2.8, and 1.4 times higher, respectively, than the heat-transfer coefficients obtained using an-e-2 ethylene glycol.