From Summary: "The independent variables considered in the analysis included stress-concentration factor, stress-load relation, wing loading, design and cruising speeds, design gust velocity, and airplane size. Several methods for estimating fatigue life from gust frequencies are discussed."

Report presenting determination of air-flow quantity in front of and behind three orifice plates to determine the errors introduced in the quantity measurements by the turbulence behind the orifice plates. For the orifice plates tested, the results showed that the measurements must be taken 40 to 60 hole diameters downstream from the plates to ensure accuracy.

Report discusses the results of yawing tests on a model of the complete hull of the XPB2M-1. The tests indicated that there was a tendency toward directional instability in the vicinity of the hump. The researchers concluded that at a certain range, the curves of yawing moment are discontinuous, and this has led to difficulty in preliminary test flights.

Report presenting the results of recent spin-tunnel tests on models of seven multiengine airplanes and compared with corresponding results for representative single-engine airplanes loaded along the fuselage. Multiengine airplanes were found to give steep spins with high rates of descent and high load factors.

Report presenting tests of the flow of air through brass tubes with the friction coefficient and incompressible flow relation as the main focus. The analytical relation between friction coefficient, tube length, and Mach number is shown for flow without shock and the conditions for flow with and without shock are delimited.

Report presenting testing of a mock-up of a pursuit airplane in the full-scale wind tunnel and the effects of propeller operation and flap deflection on the aerodynamic characteristics of the wing-fuselage combination and of the horizontal tail. The results indicate that with the flap deflected, the propeller-operating conditions cannot be directly determined from the propeller-removed lift coefficient.

Report presenting a method for obtaining exact potential-flow patterns in a compressible fluid. The method is based on a complex-function theory developed for the solutions of the simultaneous first-order partial differential equations in the hodograph variables.

Report presenting column and plate compressive strengths of extruded 24S-T aluminum alloy determined both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of a research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

Report presenting column and plate compressive strengths of extruded 75S-T aluminum alloy both within and beyond the elastic range from tests of thin-strip columns and local-instability tests of H-, Z-, and channel-section columns. The tests are part of an extensive research investigation to provide data on the structural strength of various aircraft materials. Results regarding compressive stress-strain curves and column and plate compressive strengths are provided.

Column and plate compressive strengths of extruded 24S-T aluminum alloy were determined both within and beyond the elastic range from tests of thin-strip columns and 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.

To determine the effect of piston-head temperature on knock-limited power, tests were made in a supercharged CFR engine over a range of fuel-air ratios from 0.055 to 0.120, using S-3 reference fuel, AN-F-28, Amendment-2, aviation gasoline, and AN-F-28 plus 2 percent xylidines by weight. Tests were run at a compression ratio of 7.0 with inlet-air temperatures of 150 F and 250 F and at a compression ratio of 8.0 with an inlet-air temperature of 250 F. All other engine conditions were held constant.

Report presenting testing to obtain experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. Testing occurred over a wide range of air flows and density altitudes.

Report presenting a method of constructing fins of nearly optimum proportions to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. Results regarding cooling equations, cylinder-temperature relationships, and a comparison of three cylinder cooling performances are provided.