"Several methods (references 1 and 2) based on gas-dynamic principles are available for reducing such measurements. The results obtained by these methods are subject to the limitation of the gas-dynamic theory which is that the mean free path of the molecules between impacts, is small with respect to the measuring device. Inasmuch as no information on the subject is to present known to be available, the purpose of the present paper is to present a method based on the concept of free-molecule theory for use in connection with this problem" (p. 1).

From Summary: "Various ways were tried recently to decrease the friction drag of a body in a flow; they all employ influencing the boundary layer. One of them consists in keeping the boundary layer Laminar by suction; promising tests have been carried out. Since for large Reynolds numbers the friction drag of the laminar boundary layer is much lower than that of the turbulent boundary layer, a considerable saving in drag results from keeping the boundary layer laminar, even with the blower power required for suction taken into account."

Report discussing an investigation of radioactive Chattanooga black shale found in east central Tennessee.

"A method for calculation of a counterrotating propeller which is similar to Walchner's method for calculation of the single propeller in the free air stream is developed and compared with measurements. Several dimensions which are important for the design are given end simple formulas for the gain in efficiency derived. Finally a survey of the behavior of the propeller for various operating conditions is presented" (p. 1).

"By means of characteristics theory, formulas for the numerical treatment of stationary compressible supersonic flows for the two-dimensional and rotationally symmetrical cases have been obtained from their differential equations" (p. 1).

"In an earlier report UM No.1117 by Gothert,the single-source method was applied to the compressible flow around circles, ellipses, lunes, and around an elongated body of revolution at different Mach numbers and the results compared as far as possible with the calculations by Lamla ad Busemann. Essentially, it was found that with favorable source arrangement the single-source method is in good agreement with the calculations of the same degree of approximation by Lamla and Busemann. Near sonic velocity the number of steps must be increased considerably in order to sufficiently approximate the adiabatic curve" (p. 1).

"Charts are presented for the analysis of the stability under compression of simply supported rectangular plates with one, two, three, and an infinite number of identical equally spaced longitudinal stiffeners that have zero torsional stiffness" (p. 1).

"The experimental results are presented for a part of an investigation of the compressive strength of 75S-T6 aluminum-alloy flat panels with longitudinal extruded Z-section stiffeners. This part of the investigation is concerned with panels in which the ratio of the thickness of the stiffener material to the skin material varies from 0.4 to 1.0 and the ratio of stiffener spacing to skin thickness varies from 15 to 40" (p. 1).

The present report deals with the aerodynamic, constructive, and instrumental development of a spoiler control for remote control of flying missiles.

Report presenting an experimental investigation of a series of exhaust mufflers installed on a typical six-cylinder light-airplane engine mounted on a ground dynamometer sound. Several conclusions regarding muffler design are drawn from this testing. Since engine and propeller noise are about equal for this power-plant installation, both engine-exhaust and propeller noises must be reduced to obtain a sizable reduction in overall sound-pressure level.

Note presenting an investigation to determine the effect of automatic stabilization on the lateral oscillatory stability of a hypothetical supersonic airplane. The investigation included an autopilot sensitive to either the yawing or rolling angular velocity. The results of the investigation indicated that all the automatic pilots improved the stability of the original unstable short-period oscillation.

Report of an investigation of the effect of forebody warp on the hydrodynamic qualities of a hypothetical flying boat with a hull length-beam ratio of 15 in smooth water and in waves. Warping the forebody planing bottom was found to appreciably increase the range of stable trim between the lower and upper trim limits of stability, although the center-of-gravity limits of stability were reduced.

Report discussing an Chattanooga shale adit for laboratory test samples of rock and gaining information regarding mining conditions.

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"The present report describes a new method for the prediction of the flow pattern of a gas in the two-dimensional and axially symmetrical case. It is assumed that the expansion of the gas is adiabatic and the flow stationary. The several assumptions necessary of the nozzle shape effect, in general, no essential limitation on the conventional nozzles" (p. 1).

Report presenting a method for the calculation of flutter speed of a uniform wing carrying an arbitrarily placed concentrated mass. The method involves the solution of the differential equations of motion of the wing at flutter speed and does not require the assumption of specific normal modes of vibration.

Report presenting combined force and wake survey tests on three-blade model propellers in order to determine the effects of blade-width distribution on constant-speed efficiency characteristics. The most important result is the demonstration that blade-width distribution has a marked influence on the constant-speed efficiency characteristics of propellers.

Report presenting a wind-tunnel investigation conducted in rolling flow to determine the effects of aspect ratio and sweep on the rolling stability derivatives for a series of untapered wings. The results indicated that when the aspect ratio is held constant, an increase in sweepback angle causes a significant reduction in the damping in roll at low lift coefficients for only the higher aspect ratios tested.

From Summary: "An investigation has been conducted in the NACA Cleveland icing research tunnel to determine the aerodynamic and icing characteristics of several recessed fuel-vent configurations. The vents were investigated aerodynamically to obtain vent-tube pressures and pressure distributions on the ramp surface as functions of tunnel-air velocity and angle of attack. Icing investigations were made to determine the vent-tube pressure losses for several icing conditions at tunnel-air velocities ranging from 220 to 440 feet per second. In general, under nonicing conditions, the configurations with diverging ramp walls maintained, vent-tube pressures greater than the required marginal value of 2 inches of water positive pressure differential between the fuel cell and the compartment containing the fuel cell for a range of angles of attack from 0 to 14deg at a tunnel-air velocity of approximately 240 feet per second."

The results of an experimental investigation of the downwash and wake characteristics behind a rectangular plan-form wing of aspect ratio 3.5 are presented. The airfoil section was a 5-percent-thick, symmetrical double wedge. The tests were made at a Mach number of 1.53 and a Reynolds number of 1.25 million. A comparison between experimental and theoretical values of the downwash angles is made.

Report issued by the Bureau of Mines over studies conducted on the Whiteware clay deposit. As stated in the introduction, "this report presents the factual data obtained by the investigation, which also includes data on trenching and drilling, and the results of some refractory tests and chemical analyses of representative samples of the clay later taken from some of the best trench exposures and from adit dumps" (p. 1-2). This report includes tables, maps, and illustrations.

Report issued by the Bureau of Mines over studies conducted on zinc-lead fields of Oklahoma and Kansas. Properties of the physical features, geology, and drilling are presented. This report includes tables, maps, and illustrations.

Monthly report of the U.S. Geological Survey's trace element investigations including an outline of field work, laboratory work, and staff activities that have been completed or are in process.

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.