"New application of the Lagrangian multiplier method to stability analysis are described by means of elementary examples. The use of the method in analyzing the stability of (a) clamped plates in shear and (b) plate-stiffener combinations is demonstrated. A detailed analysis for finding upper and lower limits to critical stresses of clamped rectangular plates is presented in the appendix" (p. 1).

"By consideration of antisymmetrical, as well as symmetrical, buckling configurations, the theoretical shear buckling stresses of clamped rectangular flat plates are evaluated more correctly than in previous work. The results given, which represent the average of upper- and lower-limit solutions obtained b the Lagrangian multiplier method, are within 1 1/4 percen of true buckling stresses" (p. 1).

Report presenting a low-speed wind-tunnel investigation of a scale model of an airplane with a 38.7 degree sweptback wing with an aspect ratio of 4.51, a taper ratio of 0.54, and conventional tail surfaces. Results regarding the lift characteristics, longitudinal stability, longitudinal control, directional stability, lateral control, and directional control are provided.

Note presenting results of mechanical tests of several laminated plastics, including canvas laminate molded at low pressure, grade-C canvas laminate, rayon laminate, paper laminate, and glass-fabric laminate. The following tests were performed: static tension, compression, and torsion tests; long-time creep tests at different stresses on specimens loaded in tension; fatigue tests of unnotched specimens in bending; fatigue tests of notched specimens in bending; fatigue tests in bending at temperatures of -75, 77, and 160 degrees Fahrenheit; and fatigue tests in torsion.

Report presenting flight measurements to determine the low-speed flying qualities of an airplane with a wing sweptback 35 degrees at the quarter-chord line. The lateral and directional stability and control characteristics of the airplane without slots and with 80-percent-span slots on the wing are provided.

Report presenting the results of a series of fatigue testing of aluminum-alloy sheet materials and simple riveted joints. The materials tested were 24S-T Alclad, 24S-T bare, 75S-T Alclad, R303-T275 clad, and R303-T275 bare.

"Chordwise pressure distributions are presented from experimental data obtained at six spanwise stations of a 12-foot-span wing incorporating NACA 66-series sections. The data shown were obtained at Mach numbers ranging from 0.20 to 0.60 and at angles of attack from -4 degrees to the stalling angle of attack" (p. 1).

Report presenting testing of a 12-foot-span wing with 16-percent-thick NACA 66-series sections, 2:1 taper ratio, and an aspect ratio of 6 at a range of Mach numbers to determine the effects of compressibility on the lift, pressure, and load characteristics of the wing. Results regarding lift and normal-force characteristics and load distributions are provided.

Report presenting an investigation to study the effects of changes in fuel-nozzle carbon deposition on the combustion efficiency of a single tubular-type, reverse-flow, turbojet combustor. The investigation was conducted because of the need to improve the reproducibility of combustion data for fuel-research purposes.

Report presenting testing of two representative helicopter rotors with widely different characteristics to determine the effect of wind velocity on the power required for sustentation. An appreciable decrease in power required for both rotors for a given thrust as the wind velocity increased was noted. The results for the rotors were essentially the same even though the rotors had different plan forms, airfoil sections, blade twists, and solidities.

Report presenting a source-distribution method for deriving a solution for the time-dependent surface velocity potential of thin finite wings at supersonic speeds. It is illustrated by evaluating the upwash over the tip of an arbitrary-plan-boundary wing with a supersonic and subsonic leading edge.

"Stresses were calculated by a numerical method in three reinforced monocoque cylinders subjected to pure bending. The cylinders were of circular cross section and were reinforced with 8 rings and either 8 or 16 stringers. There was a cutout on one side of each cylinder located symmetrically to the neutral plane and extending over 45, 90, or 135 degrees" (p. 1).

"Results are presented of tests of several 24S-T aluminum-alloy thin-web beams with transverse load applied at the end of an intermediate upright. A method of computing stresses and predicting failures in these directly loaded uprights is presented. A comparison between the experimental and calculated results is given" (p. 1).

From Summary: "The problem of the loss in rolling effectiveness at supersonic flight speeds is considered for the case of the rectangular wing. Equations are obtained from which can be calculated either the loss in rate of roll due to flexibility or the torsional stiffness required to maintain a given rate of roll, for two assumed variations of the spanwise distribution of torsional stiffness. A computation form and figures are provided so that calculations can be made without reference to the details of the analysis."

"Several groups of new airfoil sections, designated as the NACA 8-series, are derived analytically to have lift characteristics at supercritical Mach numbers which are favorable in the sense that the abrupt loss of lift, characteristic of the usual airfoil section at Mach numbers above the critical, is avoided. Aerodynamic characteristics determined, from two-dimensional windtunnel tests at Mach numbers up to approximately 0.9 are presented for each of the derived airfoils. Comparisons are made between the characteristics of these airfoils and the corresponding characteristics of representative NPiCA 6-series airfoils" (p. 1).

The results of an investigation to determine the two-dimensional lift and drag characteristics of nine NACA 6-series airfoil sections at three different Reynolds numbers and a comparison with a different report. The airfoils selected represent sections with variations in thickness, thickness form, and camber.

Note presenting calculations based on test data taken on a single-cylinder compression-ignition engine with a compression ratio of 13.1 and an engine speed of 2200 rpm to determine the performance at sea-level conditions of a compression-ignition engine geared together with a compressor and a turbine. The net specific power output increased with decreasing compression ratio and with increasing fuel-air ratio and engine speed.

Report presenting an experimental investigation of a blowdown turbine installed in the exhaust stream of a 12-cylinder liquid-cooled engine of 1710-cubic-inch displacement. Results regarding turbine performance and performance of complete engine systems are provided.

Note presenting a theoretical method for obtaining the aerodynamic forces acting on a thin wing in an irrotational nonuniform supersonic stream. The method is applied to determine lift and moments acting on a rectangular tail surface due to a spanwise parabolic distribution of upwash. Lift and moments due to a linear upwash distribution are also evaluated.

Report presenting an experimental investigation to determine the effect of varying the rivet diameter and pitch on the compressive strength of flat 24S-T aluminum-alloy Z-stiffened panels of the type for which design charts are available. The current investigation is concerned with panels which have various values of width-to-thickness ratio of the webs of the stiffeners and have such length that failure is by local buckling.

Report presenting an analysis of a turbine-propeller engine operating at constant speed in order to provide information regarding factors influencing optimum proportionment of power between propeller and jet, improvement in engine performance attainable from controlled proportionment of power, and control relations for optimum proportionment of power.

Report presenting a wind-tunnel investigation of the low-speed lateral control characteristics of a tapered, low-drag, semispan wing model equipped with 20-percent-chord sealed ailerons with spans of 0.954, 0.583, and 0.294 percent of a full-span aileron, each with trailing edge angles of 6, 14, and 25 degrees. The investigation included tests with the ailerons unsealed, simulating symmetrical lift-flap configurations with spans of 0.954 and 0.660 percent of a full-span flap. The results indicated that the existing theoretical method tends to give satisfactory results with the exception of ailerons with a trialing-edge angle of 25 degrees.

Note presenting results of a flight investigation of a Curtiss XP-42 airplane equipped with an all-movable horizontal tail with a control system incorporating a combination of geared unbalancing tabs and servotabs. In order to increase the stick forces for rapid deflections without affecting the forces in gradual maneuvers, the servotab linkage was modified by incorporating a viscous damper in one of the links. An investigation of the arrangement showed that the control characteristics were generally satisfactory in rapid maneuvers as well as in steady flight.

Note presenting the results of an investigation conducted to determine the effect of tail length on the spin and recovery characteristics of a model typical of a trainer-type airplane. The model used in the investigation was tested with two tail lengths, and the model with the shorter tail was tested with several ventral fins. Results indicated that the model with the longer tail length had the better recovery characteristics even when the short tail model had comparable or higher levels of tail-damping power factor.