"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).

Report discussing a mock-up injection impeller created to investigate the hydraulic characteristics and limitations of the NACA injection impeller currently in use. Information about the form and magnitude of critical factors of fuel-transfer leakage and peripheral fuel distribution is provided as well as the effects of design variations of components on hydraulic characteristics. Several revisions in portions of the impeller are suggested to improve its fuel-transfer, fuel-pumping, and fuel-equalizing characteristics.

Report presenting an investigation of the transition of the boundary layer from the laminar to the turbulent region on a flat plate, on the concave and convex side of a plate with a 20-foot radius of curvature, and on the convex side of a plate with a 30-inch radius of curvature.

Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.

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 to obtain force-test data on a wing design suitable for high-speed guided missiles, especially data on rolling moments produced in yawed and pitched attitudes. Force tests were conducted on two models of a wing design of low aspect ratio and 20 degree triangular plan form. Results regarding the application of results, four-unit wing design, and six-unit wing design are provided.

An investigation was conducted to compare the performance of two 25-ft-diam rotors which had identical dimensions and were similar in construction but different in blade airfoil-sections. Tests were conducted at indicated blade pitch angles from 3 degrees to 11.5 degrees and rotor speeds of 200, 290, and 371 rpm. The 23012.6 rotor required 2 percent less power to hover than the 0012.6. At thrust coefficients above design, the performance of the 23012.6 became better than the 0012.6 rotor.

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.

Report discussing an investigation to determine whether the crank angle for maximum rate of pressure rise can be used to indicate maximum-economy spark advance. Information about spark-advance tests at constant inlet-air pressure and fuel-air-ratio test results are provided.

"Tests were conducted to determine the effect of engine-operating variables and internal coolants on spark-advance requirements of a single cylinder from a 12-cylinder liquid-cooled engine for maximum take-off power and maximum cruise economy. The effects of fuel-air ratio, engine speed, air flow (charge density), mixture temperature, and internal coolants on peak-power (optimum) spark advance were investigated. In addition, tests were conducted to determine the effect of spark advance on the knock-limited engine performance at several mixture temperatures for conditions simulating take-off, high-power cruise, and low-power cruise" (p. 1).

Report discussing the results of testing on the suitability of six aromatic amines as fuel additives. Antiknock effectiveness, availability, physical properties, and chemical properties for knock tests were explored. The six aromatic amines were xylidines, cumidines, N-methylxylidines, N-methylcumidines, N-methylaniline, and N-methyltoluidine in 28-R aviation fuel.

Report discussing a study of automatic nonreturn air valves for use in an intermittent-jet engine. Four valve-spring materials, three valve-grill materials, and five types of valves were used. Valve A, which was made out of aluminum, was found to perform the best and last the longest.

Report discussing the effects of Mach number on the aerodynamic characteristics of an Allison powered single-engine pursuit airplane. Information about the lift, drag, pitching-moment characteristics, stability, tail effectiveness, and elevator effectiveness with Mach number is provided.

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.

"The knock-limited performance of blends containing General Motors triptane in S reference fuel and in an S plus M base fuel was determined in 17.6, F-3, F-4, and full-scale (single cylinder) engines. The results obtained are presented and are compared with published data from similar tests of 12 aromatics, 10 paraffins (including highly purified triptane), and 2 olefins. The comparison of fuels - which is based on a consideration of (a) antiknock blending sensitivity, (b) lead susceptibility, (c) temperature sensitivity, and (d) comparison of small-scale and full-scale engine data - is presented by means of bar graphs" (p. 1).

Report presenting a method of correlating the effects of compression ratio and inlet-air temperature on the knock limits of aviation fuels. Knock-limited performance tests of several fuels were run to check the method.

Report presenting an investigation to determine the effect of the amount of oil flow to the piston on the ring-sticking characteristics of a piston and ring assembly and on the engine oil consumption. Results regarding the blow-by, lubrication, oil consumption, and method of supplying oil are provided.

Report presenting a method for making lifting-surface calculations by means of magnetic measurements of an electromagnetic-analogy model. The method is based on the perfect analogy between the strength of the magnetic field around a conductor and the strength of the induced-velocity field around a vortex.

Report presenting tests conducted to determine the performance of two pressurized shunt-type cooling systems for liquid-cooled aircraft engines using a mixture of 30 percent AN-E-2 ethylene glycol and 70 percent water as the coolant. Results regarding effect of engine speed on coolant-flow rate, effect of expansion-tank pressure on coolant-flow rate, relation between pump-inlet pressure and expansion-tank pressure, variation of coolant-flow rate with pump-inlet pressure, flow rate through the shunt lines, effect of coolant-flow rate on pressure drop, effect of venturi on performance of the cooling system, and the system operating experience are provided.

Report presenting an experimental investigation of rectangular exhaust-gas ejector pump to provide data that would serve as a guide to the design of ejector applications for aircraft engines with marginal cooling. With a decrease in the quantity of air pumped and an increase in the length of an ejector, the ejector pressure rise increases to optimum values. Results regarding straight ejectors, diffuser ejectors, curved ejectors, ejector aspect ratio, divided ejectors, multistage ejectors, and nozzle-exit effects 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 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 presenting a flight investigation made to determine the effectiveness of dive-recovery flaps installed on the XP-51 airplane as a safety device for recovery from contemplated terminal-velocity dives. The flap installation is described and results are presented of measurements obtained during stick-free pull-ups and pull-outs made by deflecting the dive-recovery flaps to two selected values of flap angle .

Report discusses the results of an investigation to determine the feasibility of using the change in the specific gravity of fuels in aircraft fuel tanks to measure fuel-vaporization loss. Six fuels were tested via fuel-distillation tests and simulated-flight tests. An equation based on the specific gravity of the fuel is also described.