Report presenting a set of charts for the convenient determination of flow conditions behind a shock wave and at the surface of inclined planes and axially symmetric cones located in a uniform frictionless supersonic air stream. Shock angle, static-pressure coefficient, static-pressure ratio, total-pressure ratio, Mach number ratio, and velocity ratio for two-dimensional and conical flow fields are plotted for a range of free-stream Mach numbers.

Note presenting analytical comparisons of weights and volumes for flat-plate heat exchangers with the same calculated thermal output and friction pressure drop for three different fin configurations, including no fins, fins in both the air and exhaust gas passages, and fins in the air passages only. Two different heat exchangers were used and compared with predicted weights and volumes.

Report presenting an investigation in the stability tunnel on two semispan swept-wing models to determine experimentally the span-load distributions and to compare the experimental and theoretical results. Lift, drag, pitching moment, and stalling characteristics are provided.

Report presenting measurements of sound pressures for static conditions for two-blade, four-blade, and seven-blade propellers over a range of tip Mach numbers. Results regarding sound pressures and loudness are provided.

Note presenting comparisons of theoretical and experimental airfoil lift coefficients and pressure distributions made for two cascades of entrance vanes and three cascades of blower blades with NACA 6-series airfoils, and for one cascade of turbine blades. Results regarding the entrance vanes, blower blades, turbine blades, and possibilities of three-dimensional effects are provided.

The results of calculations of the viscous and pressure drags of some two-dimensional supersonic airfoils at zero lift are presented. The results indicate that inclusion of viscous drag alters many previous results regarding the desirability of certain airfoil shapes for securing low drags at supersonic speeds. At certain Reynolds and Mach numbers, for instance, a circular-arc airfoil may theoretically have less drag than the previously advocated symmetrical wedge-shape profile; although under different conditions, the circular-arc airfoil may have a higher drag.

Report presenting a correlation of the experimental and calculated effects of the product of inertia on the stability of lateral oscillations of airplanes. The experimental and calculated boundaries were in good agreement with one another, but neglecting the product of inertia led to wide discrepancies. Results regarding stability and its influence on general flight behavior are provided.

Note presenting theories of bending and torsion as applied to the problem of calculating the deflections in aircraft shell structures, particularly of wings. Bending as well as torsional deflections are discussed for wings without or with cut-outs.

From Summary: "The point-source-distribution method of calculating the aerodynamic coefficients of thin wings at supersonic speeds was extended to include the effect of the region between the wing boundary and the foremost Mach wave from the wing leading edge. The effect of this region on the surface velocity potential has been determined by an equivalent function, which is evaluated over a portion of the wing surface. In this manner, the effect of angles of attack and yaw as well as the asymmetry of top and bottom wing surfaces may be calculated."

Note presenting the results of pressure-distribution measurements made during high-speed wind-tunnel tests of a tapered wing of NACA 230-series airfoil sections for a range of angles of attack and free-stream Mach numbers. The peak values of minimum pressure coefficient attained were found to correspond to local Mach numbers of 1.2 to 1.4 except at angles of attack near the low-speed stall. Results regarding the wing lift characteristics, pressure coefficients and section normal-force coefficients, and a comparison of theoretical and experimental chordwise pressure distributions are provided.

Report presenting a consideration of the development of the laminar boundary layer in a compressible fluid. Formulas are given for determining the boundary-layer thickness and the boundary-layer Reynolds number, which is a measure of the boundary-layer stability, for airfoils and bodies of revolution.

Report presenting a dynamometer-stand investigation to determine the effect of exhaust pressure on the performance of a 12-cylinder liquid-cooled aircraft engine equipped with a conventional exhaust collector. The results are presented in the form of curves that show the effect of exhaust pressure on engine power, charge-air flow, volumetric efficiency, inlet-manifold mixture temperature, exhaust-gas temperature, cylinder-head temperature, and heat rejected to the coolant.

Note presenting force tests of two isolated vee-tail surfaces with various amounts of dihedral made to provide an experimental verification of a simplified vee-tail theory and the results are presented which were found to be in good agreement with calculations of previous reports. Plots of the basic test data and summaries of the data in the form of plots of the variation of static-stability derivatives and control-effectiveness parameters with dihedral angle are included.

Report presenting an investigation of the effects of simulated surface conditions, which involved exposure to various combinations of moisture, heat, and ultraviolet light, on the weight, dimensional stability, and flexural properties of reinforced plastics.

Report presenting testing of arc-welded butt joints in a 1/8-inch SAE 4130 steel sheet of aircraft quality under various conditions of welding and heat treatment in order to evaluate the effects of specific welding-technique factors on the strength of the joints. Results regarding static tension tests and fatigue tests are provided.

Note presenting an approximate method for determining the convective cooling requirement in the laminar boundary layer region of a body of revolution in high-speed flight that was developed and applied to a sample body. The convective cooling requirements were found to be small for the range of Mach numbers considered, but increased rapidly with increasing Mach number.

"Following the law of stress adopted in the Navier-Stokes equations, the configuration of the viscous flow in planes at right angles to the axis of an infinite cylinder is found to be independent of the axial motion of the cylinder. In the limiting case of a yawed or swept wing of very high aspect ratio, certain boundary-layer and separation phenomena are thus determined independently by the crosswise component of velocity" (p. 1).

Report presenting recent developments in supersonic flow theory that are applied to obtain estimates of the lift-drag ratios that may be achieved by aircraft employing sweptback wings. As the speed increases in the supersonic range, the attainable lift-drag ratios decrease and the gain due to sweepback also diminishes. Results regarding the airplane with constant chord sweptback wing, airplane with tapered wing, effect of plan form, airfoil section, friction drag, and optimum wing loading and altitude are provided.

Note presenting the relation between knock limit and blend composition of selected aviation fuel components individually blended with virgin base and with alkylate as determined in a full-scale air-cooled aircraft-engine cylinder. Results regarding mixture-response curves, relation of knock limit to blend composition, and correlation of knock ratings are provided.

Note presenting an investigation in the free-flight tunnel to obtain an experimental verification of the theoretical rudder-free dynamic stability characteristics of an airplane model equipped with a rudder with positive floating tendencies and various amounts of friction in the rudder system. Results regarding the rudder-free stability without friction and with friction are provided.

Report presenting high-speed wind-tunnel tests to determine the aerodynamic characteristics of an NACA 6-series airfoil section cambered to have critical Mach numbers higher than those for an airfoil with the same design lift coefficient with a uniform-load type of mean camber line. Comparisons are made between the characteristics of the modified airfoil and those of the NACA 66-210 airfoil with a uniform-load type of mean camber line.

Note presenting observation of the icing zones present in a warm front cloud system made during one of a series of flights designed to investigate the meteorological conditions conducive to the formation of ice on aircraft.

"The stresses in the two spars of a model of a wing having three rectangular cutouts were calculated by the PIBAL method, a modification of Southwell's method of systematic relaxations. The model was built and tested in the Polytechnic Institute of Brooklyn Aeronautical Laboratories and the deflections and strains measured were compared with calculated values. The agreement was found to be satisfactory" (p. 1).

Report presenting an investigation of a flying-boat-hull model to determine the effects on the resistance and spray characteristics of reversed-type longitudinal steps designed so that the surfaces of the steps normal to the hull bottom face inboard. Results of the tests were compared with results of a conventional flying-boat-hull model. No appreciable improvement in the resistance or spray characteristics near the hump speed was noted.