Report discussing characteristics are given for the two-blade NACA 10-(3)(062)-045 propeller and for the two-blade NACA 10-(3)(08)-045 propeller over a range of advance ratio from 0.5 to 3.8, through a blade-angle range from 20 degrees to 55 degrees measured at the 0.75 radius. Maximum efficiencies of the order of 91.5 to 92 percent were obtained for the propellers. The propeller with the thinner airfoil sections over the outboard portion of the blades, the NACA 10-(3)(062)-045 propeller, had lower losses at high tip speeds, the difference amounting to about 5 percent at a helical tip Mach number of 1.10.

From Introduction: "The results presented herein were calculated for a symmetrical diamond airfoil at zero angle of attack for a range of airfoil-thickness ratios from 0.02 to 0.10, pressure altitude from sea level to 45,000 feet, and free-stream static temperatures to -.40^o F."

Calculations have been made for the icing limit of a diamond airfoil at zero angle of attack in terms of the stream Mach number, stream temperature, and pressure altitude. The icing limit is defined as a wetted-surface temperature of 320 F and is related to the stream conditions by the method of Hardy. The results show that the point most likely to ice on the airfoil lies immediately behind the shoulder and is subject to possible icing at Mach numbers as high as 1.4.

Note presenting results from an investigation of bearing properties of some 75S-T6 and 14S-T6 aluminum-alloy hand forgings in the longitudinal and long transverse directions and in surface and center locations.

From Summary: "An analysis is made of the behavior under a loading of pure bending moment of a thin, infinitely long, pure-monocoque beam having a constant, doubly symmetric, circular-arc cross section. Bending moments, deflections, and stresses are obtained. The analysis shows a nonlinear behavior in bending which leads ultimately to a maximum amount and instability."

Note presenting calculations of the lowest normal modes of vibration of three aluminum-alloy box beams using a matrix iteration method. An experimental confirmation of the theory is also carried out and includes a determination of natural frequencies and determination of normalized mode shapes are provided.

Note presenting an analysis of the combined effect of a series of damping screens followed by an axisymmetric-stream convergence on the mean-square fluctuation-velocity intensities, scales, correlations, and one-dimensional spectra of a turbulence field convected by a main stream. Numerical results for the statistical quantities describing the turbulence field downstream of a screen-contraction configuration are obtained for the case of upstream isotropic turbulence.

Note presenting a machine which will automatically measure and record 100 pressures in a range from 5 to 65 inches of mercury, in approximately 2.5 minutes, to an accuracy of 0.1 inch of mercury. The method used is to compare the unknown pressures with a scanning pressure whose value at any instant is known in digitalized form.

From Summary: "The reduction in column strength due to initial curvature is determined theoretically for a pin-ended idealized inelastic H-section column. Equations relating load and lateral deflection are obtained which permit a systematic variation in the parameters representing the stress-strain properties, column proportions, and initial curvature of the column. The results, presented graphically, show the effect of various combinations of these parameters on column strength."

"The problem of buckling under uniform compression of flat, simply supported, rectangular plates equally spaced longitudinal stiffeners on one side of the plate is investigated. For the case of a plate with one, two, or infinitely many stiffeners, the analysis yields expressions for the effective moment of inertia of the stiffeners that can be used in conjunction with the buckling charts previously presented in NACA TN 1825" (p. 1).

Report presenting a simplified analysis to estimate the extent to which the pressure ratio and power of a nonreturn supersonic wind tunnel operating in the low supersonic Mach number range can be reduced by the evaporation of water injected into the diffuser. It appears to be possible to reduce the power by as much as 20 percent for a typical example of a tunnel operating at Mach number 1.4.

Report analyzing and discussing the problems associated with providing icing protection for the critical components of a typical turbojet transport airplane operating over a range of probable icing conditions. Heating requirements for several thermal methods of protection are evaluated and the airplane performance penalties associated with providing protection from various energy sources are provided.

"The problems associated with providing icing protection for the critical components of a typical turbojet transport airplane operating over a range of probable icing conditions are analyzed and discussed. Heating requirements for several thermal methods of protection are evaluated and the airplane performance penalties associated with providing this protection from various energy sources are assessed. The continuous heating requirements for icing protection and the associated airplane performance penalties for the turbojet transport are considerably increased over those associated with lower-speed aircraft" (p. 1).

Note presenting an investigation of the gases evolved during the firing of vitreous coatings. The scope of the investigation included an examination of gas evolution with a microscope while specimens were being fired, examinations of fired specimens for changes in bubble structure with firing time, examination of changes in normal gas evolution when water-free enamels were used, analysis with the mass spectrometer of gases trapped in the bubble structure, determination of the source of carbon gases in the bubble structure with radioactive carbon as a tracer, and determination of the effect of various pretreatments of the clay used for suspending the coating slip on the resulting bubble structure of the fired specimens.

Note presenting a study of the stability of the mixing of two streams both for the interest in the problem and for clarifying certain points in the basic stability theory. Results show that when the relative speed of the two parallel streams exceeds the sum of their velocities of sound, subsonic oscillations cannot occur and the mixing region can be expected to be stable with respect to small disturbances.

Note presenting a damped sine-wave elevator motion used as a basis for computing the design maneuvering load on the horizontal tail. The results indicated that the maneuvering tail-load variation computed by operational methods with the assumed damped sine-wave elevator motion agreed closely with the loads computed by a method currently used by the US Air Force.

Note presenting the basic equations of Timoshenko for the motion of vibrating non-uniform beams, which allow for effects of transverse shear deformation and rotary inertia, in several forms, including one in which the equations are written in the directions of the characteristics. Numerical traveling-wave solutions are obtained for some elementary problems of finite uniform beams for which the propagation velocities of bending and shear discontinuities are taken to be equal.

"The principal planing characteristics have been obtained for two V-shaped prismatic surfaces having angles of dead rise of 20 degrees and 40 degrees. The load, wetted lengths, resistance, center-of-pressure location, and limited drag data are presented for speed coefficients up to 25.0, beam-loading coefficients from 0.85 to 87.33, keel-wetted-length-beam-ratios up to approximately 8.0, and trims up to 30 degrees. The data indicate that, for a given condition of load, speed, and trim, the wetted length, the distance of the center of pressure from the trailing edge, and the drag increase with an increase in the angle of dead rise" (p. 1).

Report presenting the results of an experimental investigation of the problem of reducing the descending velocity of a helicopter model in steady vertical autorotation by expending the kinetic energy of the rotor in a collective-pitch flare. Test data were obtained over a wide range of operating conditions from a freely falling model rotor restrained laterally by a guide wire. Results regarding justification of initial conditions, effect or rate of change of blade pitch angle, effect of final blade pitch angle, effect of rotor inertia and disk loading, and semiempirical theory are provided.

Note presenting an investigation of the interaction of an oblique shock with a laminar boundary layer in a compressible supersonic stream. This report is a complement to previous report and uses the differential equation method.

Report presenting the determination of the rate of vaporization of a pure liquid from a spherical surface exposed to a gas stream of varying static pressure, which required the use of a heat-balance equation. Results regarding the effect of pressure on Nusselt number, momentum-transfer groups, application of momentum-transfer groups to heat and mass transfer, and effect of pressure on driving potential are provided.

Note presenting an examination of the applicability of some results from the theory of generalized harmonic analysis (or power-spectral analysis) to the analysis of gust loads on airplanes in continuous rough air. The general relations for linear systems between power spectrums of a random input disturbance and an output response are used to relate the spectrum of airplane load in rough air to the spectrum of atmospheric gust velocity.

Report presenting a theoretical analysis made of a pitch-attitude control system as applied to a swept-wing fighter airplane. The system is investigated with and without pitch-rate feedback. The effects of varying gain settings, Mach number, altitude, and variations of elevator deflection, normal acceleration, and flight path are provided.

Note presenting an investigation of the phenomena encountered when a plane oblique shock wave is incident upon the boundary layer of a flat plate. The flow field was divided into a viscous layer near the wall and a supersonic potential outer flow. With the outer flow determined, boundary-layer growth and pressure distribution were computed and results for the laminar cases were obtained and provided.