Report presenting a modification of the passage contour of a 48-inch centrifugal impeller by changing the shape of the blades with the objective of reducing the deceleration rates along the blade faces and thereby improving the internal efficiency of the impeller. The modified impeller was found to show a general improvement in efficiency throughout the passage over that of the original impeller.

Results of a low-speed wind-tunnel investigation to determine the effect of high-lift devices on the static lateral stability derivatives and the yawing derivatives of an untapered 45 degrees sweptback wing are presented. The tests were made in the curved-flow test section of the Langley stability tunnel at a Reynolds number of 1.1 X 10 to the sixth power.

Note presenting a description of basic electrical networks that compensate for the thermal time lag of thermocouple and resistance thermometer elements used in combustion research and in the control of jet power plants. The measurement or the detection of rapid temperature changes by use of such elements can thereby be improved.

Note presenting a study that is part of a program of experimentation with external noise reduction on light airplanes. Two light airplanes modified by reduction gears, four-bladed propellers, and engine exhaust silencers were flown in comparison with two standard airplanes at a number of sites that may be useful as landing strips. Some conclusions regarding the number and types of complaints received are provided.

Note presenting graphs for rapid evaluation of air-induction systems from considerations of their aerodynamic-performance parameters in combination with power-plant characteristics. The graphs cover the range of supersonic Mach numbers up to 3.0. The illustrative examples indicate that the inlet area required for optimum performance must change with altitude at a fixed Mach number as well as with Mach number at a fixed altitude.

"A derivation of the form of the incompressible turbulent skin-friction law for an insulated flat plate is made in such a way that it may be extended to compressible flows. The ratio of compressible to incompressible skin friction is obtained, and the results are shown to be in agreement with existing experimental results" (p. 1).

From Introduction: "The purpose of the present paper is twofold. First, a close connection will be established between reverse-flow theorems in subsonic and supersonic, steady-state wing theory and known reciprocity relations between two solutions of the equation the flow field."

Report presenting a technique for obtaining a physical picture of the flow behind a wing, combination of wings, or other aircraft components is described. The technique involves photographing from far downstream the action of a large number of tufts of uniform length mounted on a screen. Results regarding the angle of attack variations at zero yaw, effect of sideslip, deflecting tip controls, and yawing oscillation tests are provided.

Previously published methods for stress and strength analysis of plane and curved shear webs working in diagonal tension are presented as a unified method. The treatment is sufficiently comprehensive and detailed to make the paper self-contained. Part 1 discusses the theory and methods for calculating the stresses and shear deflections of web systems as well as the strengths of the web, the stiffeners, and the riveting. Part 2, published separately, presents the experimental evidence. (author).

Report presenting the experimental evidence regarding the analysis of web systems working in diagonal tension given in Part I of the paper.

From Summary: "The principles involved in the operation of several types of stall-warning devices are described and conditions under which difficulty may be experienced are pointed out. In the discussion, stall-warning devices are grouped as special stall-sensing devices and angle-of-attack-sensing devices. Methods of transmitting the warning to the pilot are also discussed. Some specific examples of stall-warning devices are illustrated and described."

Report presenting a background for various general phases of the aircraft-noise problem. The effects of noise are discussed and brief discussions of the physical characteristics of aircraft noise and some ways of protection from noise are included, as well as a bibliography of research related to the noise problem. At the time of this report, no easy and inexpensive solution to the aircraft-noise problem is currently available.