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.

"A flight investigation of a 1/7-scale rocket-powered model of the XF10F Grumman XF10F airplane in the swept-wing configuration has been made. The purpose of this test was to determine the static longitudinal stability, damping in pitch, and longitudinal control effectiveness of the airplane with the center of gravity at 20 percent of the wing mean aerodynamic chord. Only a small amount of data was obtained from the test because, immediately after booster separation at a Mach number of 0.88, the configuration was directionally unstable and diverged in sideslip" (p. 1).

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.

Note presenting an analysis and comparison of atmospheric turbulence as experienced by rocket-powered models and temperature lapse-rate data obtained from rawinsonde soundings in 38 cases by using an assumed temperature lapse-rate stability boundary as a basis for comparison. A limited correlation has been obtained which indicates that atmospheric conditions classified as being unstable will generally be turbulent, but a marginal or stable classification does not necessarily indicate smooth air.

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."

"A flight test was made to determine the servoplane effectiveness and stability characteristics of the free-floating horizontal stabilizer to be used on the XF10F airplane. The results of this test indicate that servoplane effectiveness is practically constant through the speed range up to a Mach number of 1.15, and the stabilizer static stability is satisfactory. A loss of damping occurs over a narrow Mach number range near M = 1.0, resulting in dynamic instability of the stabilizer in this narrow range" (p. 1).

"The rocket-propelled-model technique has been applied to the investigation of low-lift buffeting. Results of preliminary tests show that severe buffeting, wing dropping, and normal-force changes occur almost simultaneously near zero lift over a Mach number range near 0.9 on unswept wings 12 percent thick. On unswept wings 7 percent thick, buffeting did not occur; however, mild wing dropping and normal-force changes were experienced" (p. 1).

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.

"A method of analysis based on slender-wing theory is developed to investigate the characteristics in roll of slender cruciform wings and wing-body combinations. The method makes use of the conformal mapping processes of classical hydrodynamics which transform the region outside a circle and the region outside an arbitrary arrangement of line segments intersecting at the origin. The method of analysis may be utilized to solve other slender cruciform wing-body problems involving arbitrarily assigned boundary conditions" (p. 1).

Report presenting a theoretical approach to determine the lateral frequency response of a fighter airplane to side gusts and rolling gusts at a Mach number of 0.7 and an altitude of 30,000 feet. Frequency response and power spectral density were determined with the controls fixed and in combination with three different basic types of attitude autopilots.

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.

"An analysis is made of the effects of compressibility on the pressure coefficients about several bodies of revolution by comparing experimentally determined pressure coefficients with corresponding pressure coefficients calculated by the use of the linearized equations of compressible flow. The results show that the theoretical methods predict the subsonic pressure-coefficient changes over the central part of the body but do not predict the pressure-coefficient changes near the nose. Extrapolation of the linearized subsonic theory into the mixed subsonic-supersonic flow region fails to predict a rearward movement of the negative pressure-coefficient peak which occurs after the critical stream Mach number has been attained" (p. 1125).

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.

"The equations presented in this report give the interference on the trailing-vortex system of a uniformly loaded finite-span wing in a circular tunnel containing partly open and partly closed walls, with special reference to symmetrical arrangements of the open and closed portions. Methods are given for extending the equations to include tunnel shapes other than circular. The rectangular tunnel is used to demonstrate these methods. The equations are also extended to nonuniformly loaded wings" (p. 361).

Report presenting some equations that give the interference on the trailing-vortex system of a uniformly loaded finite-span wing in a circular tunnel containing partly open and partly closed walls, with special reference to symmetrical arrangements of the open and closed portions. Methods are given for extending the equations to include tunnel shapes other than circular.

Note presenting pressure-distribution expressions and stability derivatives derived by use of linear theory for zero-end-plate triangular vertical tails with subsonic leading edges performing rolling, yawing, and constant-lateral-acceleration motions. Corresponding results for the sideslip motion, most of which have been previously reported, are also included.

Report presenting drag coefficients during power-off transonic flight for the Bell X-1 airplane with a 10-percent-thick wing over a range of Mach numbers and pressure altitudes. The data was compared to an X-1 with an 8-percent-thick wing and a wind tunnel test with a 10-percent-thick wing. Information about necessary angle of attack, drag-rise Mach number, maximum lift-drag ratio, and drag coefficient at zero lift is provided.