Note presenting a general theory of steady three-dimensional flow of a nonviscous fluid in subsonic and supersonic turbomachines with arbitrary hub and casing shapes and a finite number of blades. The equations obtained to describe the fluid flow on these stream surfaces show clearly the several approximations involved in ordinary two-dimensional treatments.

Report presenting the use of linearized theory for compressible unsteady flow to obtain the velocity potential and lift and moment for a thin, harmonically oscillating, two-dimensional wing-aileron combination moving at sonic speed.

Report presenting an analysis of airfoil data from several NACA 16-series propeller airfoils from tests of 5-inch chord models in the 24-inch high-speed tunnel and 12-inch-chord models in the 8-foot high-speed tunnel. Results indicated that differences of less than 1 percent in propeller efficiency at or near the design condition will be involved in applying data from 5-inch-chord and 12-inch-chord airfoil tests to full-scale propeller design.

Report presenting experimental data obtained in the 4- by 4-foot supersonic tunnel for a parabolic body of revolution of large fineness ratio at mach number 1.59, which are analyzed in order to locate positions at which static-pressure orifices will indicate a constant static pressure independent of the pitch-yaw attitude of the body.

Report presenting a general method of design is developed for two-dimensional unbranched channels with prescribed velocities as a function of arc length along the channel walls. The method is developed for both incompressible and compressible, irrational, nonviscous flow. Five numerical examples are given including three elbow designs with the same prescribed velocity as a function of arc length along the channel walls but with incompressible, linearized compressible, and compressible flow.

"An impulse-momentum method for determining impact conditions for landing gears in eccentric landings is presented. The analysis is primarily concerned with the determination of contact velocities for impacts subsequent to initial touchdown in eccentric landings and with the determination of the effective mass acting on each landing gear. These parameters determine the energy-absorption requirements for the landing gear and, in conjunction with the particular characteristics of the landing gear, govern the magnitude of the ground loads" (p. 1).

Note presenting the use of the Crocco method to solve the simultaneous differential equations of momentum and energy involved in the flow of air in a thin laminar boundary layer on a flat plate. The Crocco method was used because it gave accurate results for arbitrary Prandtl number near unity. Variations of shear, velocity, temperature, and Mach number across the boundary layer are included.

From Summary: "Theoretical solutions are presented for the buckling in uniform axial compression of two types of simply supported curved sandwich plates: the corrugated-core type and the isotropic-core type. The solutions are obtained from a theory for orthotropic curved plates in which deflections due to shear are taken into account. Results are given in the form of equations and curves."

Report presenting the results of experiments conducted to determine time constants of several bare-wire thermocouples mounted in cross flow to an air stream. Four pairs of common thermocouple materials with three different wire diameters were used. Results regarding the time constants, Nusselt numbers, effective gas temperature, and some numerical calculations are provided.

An investigation and analysis of the motions of four fully rolled-up vortices representing the vortex system trailing behind cruciform wings by theoretical and visual-flow methods. Equations are developed for the three-dimensional paths traced by the vortices behind a cruciform wing banked 45 degrees, and calculations are made of the distance behind the wing at which the upper two vortices pass through the lower two.

Note presenting the design of an instrument utilizing Wheatstone bridge type of pressure sensing units that is capable of integration of airfoil pressures into a quantity representative of the normal force and pitching moment acting on the airfoil. Flight and wind-tunnel versions of the instrument are briefly described along with samples of test data obtained from them.

An analysis was made to determine the applicability of existing propeller theory and the theory of oscillating airfoils to the problem of determining the magnitude of the forces on propellers in pitch or yaw. Strip calculations using compressible airfoil characteristics were first made as though steady-state conditions existed successively at several blade positions of the propeller blades during one revolution. A theory of oscillating airfoils in pulsating incompressible potential flow was then considered from which it was possible to determine factors which would modify the steady-state forces.

Powered models of three different flying boats were landed in oncoming waves of various heights and lengths. The effects of varying the trim at landing, the deceleration after landing, and the size of the waves were determined. Data are presented on the motions and accelerations obtained during landings in rough water.

Contributions of vertical tail and fuselage to directional stability are determined from pressure distributions measured over wide ranges of angle of attack and angle of yaw with stabilizer in each of three vertical positions, with stabilizer removed and with both stabilizer and vertical tail removed. Results point out inadequacies of current design methods and show that more accurate methods must treat separately contributions of vertical tail, fuselage area above stabilizer, and fuselage area below stabilizer.

Note presenting a method for proportioning thin-web beams to attain equal strength of web and uprights which may in turn be employed toward optimum design of these components. Improved empirical formulas for this purpose are developed the results checked by experimental loading of six beams.

From Summary: "Accurate spotaneous ignition temperatures have been determined for some 50 pure organic compounds. The effects of a wide variety of additives and of eight selected metals on the spontaneous-ignition-temperature values of representatives of this group also have been observed. Results are correlated with chemical structure and with antiknock characteristics where known; more fundamental aspects of the possible chain-breaking and chain-branching reactions involved are also considered."

Note presenting a device developed to measure local skin friction on a flat plate by measuring the force exerted upon a very small movable part of the surface of a flat plate. The device is applied to both low-speed and high-speed measurements. The paper describes the design and construction of the device and the results of the measurements.

Report presenting the compressive stress for buckling for a rectangular flat sandwich plate with loaded edges simply supported and unloaded edges rigidly clamped. The true values of the buckling stress are estimated as the arithmetic means of these bounds and are presented in a diagram which covers the entire practical range of the geometric and mechanical quantities involved.

"In the yield region of the stress-strain curve the variation in Poisson's ratio from the elastic to the plastic value is most pronounced. This variation was studied experimentally by a systematic series of tests on several aluminum alloys. The tests were conducted under simple tensile and compressive loading along three orthogonal axes" (p. 1).

Report presenting flight-test measurements and pilots' opinions of the longitudinal flying qualities and lateral control characteristics of a small single-rotor helicopter. The damping of the helicopter in pitch and roll was varied by means of a rate-sensitive automatic-control device from the device inoperable to nearly three times that amount. Results regarding the determination of damping, pull-up time histories, time for curve of acceleration to become concave downward in pull-ups, longitudinal oscillations, and lateral control are provided.

Note presenting the hydrodynamic characteristics of a flying boat incorporating a low-drag, planing-tail hull as determined from model tests made in tank no. 2 and compared with tests of the same flying boat incorporating a conventional type of hull. The planing-tail model had a greater range of elevator deflection and center-of-gravity location for stable take-offs than did the conventional model.

Report presenting an investigation of the hodograph method as it is applied in general to the problem of compressible flow.

Report presenting an investigation of the influence of cold-working on the creep properties of an alloy containing 20 percent cobalt, 20 percent chromium, 20 percent nickel, and balance iron and on the same alloy modified by small additions of tungsten alone or tungsten, molybdenum, and columbium in combination. The effects of cold-working were the same on all alloys studied. Results regarding the amount of cold reduction for maximum creep resistance, diffraction lines, stress relaxation properties, and properties of similarity across all alloys are provided.

Note presenting a consideration of Rayleigh's problem for a compressible viscous gas, subject to slip at the wall. Expressions for slip velocity and skin friction are derived with the gas temperature at the wall and the product of viscosity times density assumed constant, or nearly so. The results of the solution are interpreted to define the border region between continuum and slip flow and to estimate the effect of slip.