Report presenting climb and high-speed tests of a Hamilton Standard No. 6507A-2 three-blade propeller, which have been made to determine the effect of blade loading on propeller efficiency. The normal and military power climb efficiencies were found to be about equal at altitudes below 16,000 feet.

Report presenting drag measurements made on a 10-percent-thick wing and 8-percent-thick tail and a 8-percent-thick wing, 6-percent-thick tail version of the X-1 airplane at a variety of Mach numbers. The drag of the thicker wing was found to be much higher than that of the thinner wing. The fuselage was found to cause interference with the wing of both models, making the separation of wing and fuselage drag difficult to determine.

"Flight tests to determine propeller performance have been made of a Curtiss No. 838-102-18 three-blade propeller having trailing-edge extensions on a Republic P-47D-28 airplane in climb and high speed. These tests are a part of a general propeller flight-test program at the Langley Laboratory of the National Advisory Committee for Aeronautics. Results of climb tests indicate that when power is changed from approximately 1475 horsepower at 2550 rpm (roughly normal power) to 2400 horsepower at 2700 rpm (approximately military power) there is a loss in propeller efficiency of 3 percent at an altitude of 7000 feet, and 4 percent at 21,000 feet" (p. 1).

Report presenting a general analysis that allows the rolling motions of an aircraft using a displacement-response, flicker-type automatic pilot to be determined. The system is not ideal for many stabilization problems due to inherent residual oscillations, but it offers a simple and economical solution in situations in which steady state oscillations are not a problem. Results regarding some general remarks, transient and steady states, stabilization boundaries, amplitude equations, and period equations are provided.

Report discussing testing of a model of the pilotless aircraft RM-1 to measure aileron hinge moments in flight in order to determine the reason for loss of roll stabilization at supercritical speeds in flight. The aileron was found to become quickly underbalanced over the full deflection range at supercritical speeds. Information about the general flight behavior, aileron hinge moments, and roll stabilization of the model is provided.

Report presenting a flight test of a supersonic research pilotless aircraft in which large-amplitude aileron oscillations, most likely aileron compressibility flutter, were encountered in the transonic and supersonic speed ranges. Results regarding power-on flight and coasting flight are provided.

"In the first part, the boundary conditions for an open wind tunnel (incompressible flow) are examined with special reference to the effects of the closed entrance and exit sections. In the second part, solutions are derived for four types of two-dimensional open tunnels, including one in which the pressures on the two free surfaces are not equal. In the third part, a general method is given for calculating the boundary effect in an open circular wind tunnel of finite jet length" (p. 509).

Report in two parts: one examines the boundary conditions for an open wind tunnel with special references to the effects of the closed entrance and exit sections, while the other derives solutions of four types of two-dimensional open tunnels, including one in which the pressures on the two free surfaces are not equal.

From Summary: "By the use of a form of the Prandtl-Glauert method that is valid for three-dimensional flow problems, the value of the maximum incremental velocity for compressible flow about thin ellipsoids at zero angle of attack is calculated as a function of the Mach number for various aspect ratios and thickness ratios. The critical Mach numbers (within the accuracy of the Prandtl-Glauert method) of the various ellipsoids are also determined. The results indicate an increase in critical Mach number with decrease in aspect ratio which is large enough to explain experimental results on low-aspect-ratio wings at zero lift."

Report presenting the horizontal and vertical components of the induced velocity in front of an inclined propeller in a horizontal stream obtained by a magnetic-analogy method. The problem was formulated in terms of the linear theory of the acceleration potential of an incompressible nonviscous fluid.

Note presenting an analysis based on simple geometry of the effect of thrust-axis inclination on propeller disk loading. Calculations are in excellent agreement with available flight measurements, so that the analysis is indicated to be adequate for predicting the primary effects of inclination. Because of the possible large effects of wing and fuselage interference, flow angles at the propeller should be determined by survey for most accurate results.

Report presenting pressure distributions over a prolate spheroid of fineness ratio 6 and over a combination of this body with an NACA 65-010 wing section for a range of Mach numbers. Results regarding wall and sting interference, nature of flow over a model in the transonic region, development of supersonic flow from subsonic flow, and a comparison of experimental and theoretical flow at subsonic stream Mach numbers are provided.

Report presenting an analysis of the effects of compressibility on the pressure coefficients of several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of linearized equations of compressible flow. The results indicated that the theoretical methods predict the subsonic pressure-coefficient changes over the central portion of the body but do not predict the pressure-coefficient changes near the nose.

Report presenting an investigation of the closed wind-tunnel phenomenon of choking and the wall-constriction effects in the subsonic Mach number range where supersonic Mach numbers appear using the hydraulic analogy. Application of the results to wind tunnel testing, the subsonic choking phenomena, and effects of the walls are described.

"An investigation was made in the Cleveland Altitude wind tunnel to determine the performance of an Aeroproducts H20C-162-X11M2 four-blade propeller on a YP-47M airplane at high blade loadings and high engine powers. The propeller characteristics were obtained for a range of power coefficients from 0.30 to 1.00 at free-stream Mach numbers of 0.40 and 0.50. The results of the force measurements are indicative only of trends in propeller efficiency with changes in power coefficient and advance-diameter ratio because unknown interference effects existed during the investigation" (p. 1).

Report presenting an investigation to obtain the pressure distribution over a sharp-nose body of revolution with a circular-arc profile and fineness ratio 6 at transonic speeds using the NACA wing-flow method. Results regarding the variation of pressure coefficient with Mach number, pressure distributions along the body axis, pressure drag, and effects of interference and horizontal gradient are provided.

Note presenting fairing compositions applied to aircraft surfaces, welds and junctions of metal plates, and rivet depressions to improve the aerodynamic efficiency of the airplane at high speeds. A method is described for formulating fairing compositions which have, within limits, desired coefficients of thermal expansion. Results regarding water-immersion tests, thermal expansion and softening temperature, temperature-cycle tests, and density are provided.

Report presenting the design of a two-stage, solid-fuel, rocket-propelled, general research pilotless aircraft suitable for investigating stability and control at supersonic velocities. The flight test investigation is described and information is provided for zero-length launchers and operational flight-test techniques of two-stage rockets. Results regarding launching characteristics and lateral stabilization and control flight tests are provided.

Memorandum presenting an approximate subsonic theory developed for the solid blockage interference in circular wind tunnels with walls slotted in the direction of flow. The theory indicated the possibility of obtaining zero blockage interference. Tests in a circular slotted tunnel based on the theory confirmed the theoretical predictions.

Report presenting the application of transient theory to the rational determination of dynamic loads on airplane structures during initial landing impact. Simplified procedures are described by which the distribution of the maximum attainable value of the dynamic stresses in the structure may be obtained.

"The analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, given in NACA TN no. 1423, is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds. The lift, rolling moment due to sideslip, and damping in roll and pitch for this more general case have been treated elsewhere on the basis of the theory of small disturbances. The surface potentials for angle of attack and rolling taken therefrom are used to obtain the several side-force and yawing-moment derivatives that depend on leading-edge suction, and a tentative value for the rolling moment due to yawing" (p. 317).

Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.

Report presenting the analysis of the stability derivatives of low-aspect-ratio triangular wings at subsonic and supersonic speeds, which is extended to apply to triangular wings having large vertex angles and traveling at supersonic speeds.

Report includes the National Advisory Committee for Aeronautics letter of submittal to the President, summaries of the committee's activities and research accomplished, bibliographies, and financial report.