"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).

Report presenting a series of tests made in the 15-foot free-spinning tunnel to study the spin characteristics of a model of a hypothetical canard airplane, which was designed to be about the same size and have the same general aerodynamic characteristics as a Boeing B-247 airplane. The model spun normally and had excellent recovery characteristics.

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.

"An investigation was made of the static longitudinal stability, and control and stall characteristics of XBTK-1 dive bomber. Results indicate that the longitudinal stability will probably be satisfactory for all contemplated flight conditions at the rear-most CG location with elevator both fixed and free. Power effects were small. Sufficient elevator control will be available to trim in any flight condition above the ground" (p. 1).

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 an analysis and simple method to help solve the problem of assisting the take-off of an airplane by means of auxiliary jet propulsion by determining the jet thrust and weight of jet fuel required to provide a desired reduction in take-off distance or increase in pay load or fuel load for a fixed take-off distance. The use of previous experimental work to verify the analysis is also provided.

Test of a ducted body with Internal flow were made in the 8-foot high-speed wind tunnel for the purpose of studying the effects on external drag and an critical speed of the addition of efficient inlet and outlet openings to a basic streamline shape. Drag tests of a 13.6- inch-diameter streamline body of fineness ratio 6.14 were made at Mach numbers ranging from 0.20 to 0.75. The model was centrally mounted on a 9-percent-thick airfoil and was designed to have an efficient airfoil-body juncture and a high critical speed.

"The effect on static-pressure measurements of locating a pitot-static tube 0.55 chord ahead of an airfoil section has been investigated. The tests were conducted in the NACA 24-inch high-speed tunnel on airfoil sections of various thickness ratios over a large range of Mach number. The results show that for a wing having a thickness ratio of 0.15 the measured Mach number, determined from a pitot-static-tube reading, is approximately 0.01 too low at a stream Mach number of 0.4 and approximately 0.03 too low at a Mach number of 0.8" (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 presenting the reasons for the existence of bending stresses due to torsion and the theoretical formulas applying to rectangular boxes with finite bulkhead spacing. Tests are described which were made to verify the theory, strains being measured on a rectangular torsion box with four bulkhead spacings. Results regarding normal stresses are provided.

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.

"The thrust produced by a variety of exhaust stacks and nozzles, and the effect of these stacks and nozzles on the power of a single-cylinder R-2800 engine were investigated over a wide range of engine speeds and manifold pressures in a series of tests in the Pratt & Whitney experimental test department. From the data obtained it is possible to estimate the optimum form of nozzles and the available thrust for airplanes fitted with R-2800 engines under sea-level conditions" (p. 1).

"A study was made of the performance of a jet-propulsion system composed of an engine-driven blower, a combustion chamber, and a discharge nozzle. A simplified analysis is made of this system for the purpose of showing in concise form the effect of the important design variables and operating conditions on jet thrust, thrust horsepower, and fuel consumption. Curves are presented that permit a rapid evaluation of the performance of this system for a range of operating conditions" (p. 1).

Report presenting seven distinct operations in the preparation of 2,2,4,4-tetramethylpentane, including the preparation of di-isobutylene hydrochloride, preparation of dimethylzinc, reaction of dimethylzinc in dry benzene with di-isobutylene hydrochloride, preliminary distillation of the reaction products, treatment of the first distillate with sodium and alcohol, final distillation after appropriate washing of the products, and recovery of the iodine in the zinc residues of II as methyl iodide.

"Tests were made of riveted double-angle columns to determine the total rivet strength that is required to make these built-up columns develop the strength predicted by the standard column formulas. Results of the tests led to the conclusion that the required rivet strength may be calculated by the beam method of design" (p. 1).

Report presenting testing at two engine speeds on six representative fuels rated at 100-octane number by the C.F.R. aviation method. Blends of the fuels with benzene, toluene, xylene, and isopropyl comprise nine other fuels, leading to testing on 15 fuels. Results regarding the tests at 2000 rpm and 250 degrees Fahrenheit inlet-air temperature, at 3100 rpm and 250 degrees Fahrenheit inlet-air temperature, 2000 rpm and 150 degrees Fahrenheit inlet-air temperature, and 3100 rpm and 150 degrees Fahrenheit inlet-air temperature, effect of speed on knock rating, effect of inlet-air temperature on knock rating, and effect of spark advance on knock rating are provided.

Report includes tension fatigue test results on the following types of samples of 0.040-inch alclad 24s-t: (1) monoblock sheet samples as received and after a post-aging heat treatment, (2) "sheet efficiency" samples (two equally stressed sheets joined by a single transverse row of spot welds) both as received and after post-aging, (3) spot-welded lap-joint samples as received and after post-aging, and (4) roll-welded lap-joint samples. (author).

"The results of a series of tests to determine the effect of internal pressure on the buckling load of a thin cylinder under an applied torque indicated that internal pressure raises the shear buckling stress. The experimental results were analyzed with the aid of previously developed theory and a simple interaction formula was derived" (p. 1).

"The design of curved sheet panels to resist shear involves a consideration of several factors: the buckling resistance of the sheet, the stress at which buckling becomes permanent, and the strength which may be developed beyond the buckling limit by tension-field action. Although some experimental as well as theoretical work has been done on the buckling and tension-field phases of this problem, neither of these types of action appears to be very well understood. This report presents the results of the first series of torsion tests of stiffened circular cylinders to be completed in connection with this study at Aluminum Research Laboratories" (p. 1).

Report presenting performance data on a Trane exhaust gas and air heat exchanger. Heat transfer rates were measured using specified exhaust gas rates and ventilating-air rates. The measured thermal outputs and static pressure drops are compared with predicted magnitudes.

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.