Report presenting an investigation to determine the effect of the location of the diffuser vanes with respect to the supercharger outlets and the effect of flow conditions at the impeller inlet on the air-flow distribution in the outlets of the engine-stage supercharger of an 18-cylinder double-row radial aircraft engine. The effect of flow conditions at the impeller inlet was investigated by distorting the flow at the inlet and noting the effect in the supercharger outlets. Results regarding the diffuser effect and inlet effect are provided.

From Introduction: "The present report has been prepared to discuss the indications obtained from the University of Chicago turbulence indicator in relation to simultaneous measurement of atmospheric gustiness made by the NACA, which are summarized herein."

Report presenting knock testing of a sensitive fuel and a relatively insensitive fuel in a full-scale air-cooled cylinder. Six engine variables were investigated: fuel-air ratio, compression ratio, inlet-air temperature, spark advance, exhaust pressure, and cylinder temperature.

Abstract: In the NaF-UF4 system the following intermediate phases have been found: NaUF5, -Na2UF6, -Na2UF6 and NacUF7. NaLaF4 is the only intermediate phase observed in the system NaF-LaF3. In the course of an incomplete study of the system NaF-ThF4 the phases NaTh2F9, -Na2ThF6, -Na2ThF6 and Na4ThF8 have been observed. Crystal structure data are given for all the phases.

"In the present report the true weight distribution law of the wing structure along the span is investigated. It is shown that the triangular distribution and that based on the proportionality to the chords do not correspond to the actual weight distribution, On the basis of extensive data on wings of the CAHI type airplane formulas are obtained from which it is possible to determine the true diagram of the structural weight distribution along the span from a knowledge of only the geometrical dimensions of the wing" (p. 1).

"The present report is concerned with an analytical treatment of the effects of the transverse inclination of an airplane in a turn on the indication of the directional gyro. It is found that the extreme inclinations which the airplane must necessarily assume for a correct turn in the approaches executed at high speed and small radius of curvature, renders the indications of the instrument worthless during such maneuvers" (p. 1).

Data are presented of the flow conditions in the vicinity of an NACA D sub S -type cowling. Tests were made of a 1/2 scale-nacelle model at inlet-velocity ratios ranging from 0.23 to 1.02 and angles of attack from 6 deg to 10 deg. The velocity and direction of flow in the vertical plane of symmetry of the cowling were determined from orifices and tufts installed on a board aligned with the flow. Diagrams showing velocity ratio contours and lines of constant flow angles are given.

Report issued by the U.S. Bureau of Mines on the exploration of the Mount Hope mine. Analysis of samples obtained from core-drilling are listed. This report includes tables, maps, and illustrations.

"The theory of small disturbances is applied to the calculation of the pressure distribution and drag of a closed body of revolution traveling at supersonic speeds. It is shown that toward the rear of the body the shape of the pressure distribution is similar to that for subsonic flow. For fineness ratios between 10 and 15 the theoretical wave drag is of the same order as probable values of the frictional drag" (p. 1).

Report presenting an investigation of the cooling of an 18-cylinder, twin-row, radial, air-cooled engine in a high-performance pursuit airplane for variable engine and flight conditions at a range of altitudes to provide a basis for predicting high-altitude cooling performance from sea-level or low-altitude test results.

Note presenting an investigation of the effects on the aerodynamic characteristics of skin wrinkles on the forward part of the upper surface of two NACA airfoils. The results showed that no appreciable change in normal-force or pitching-moment characteristics over the range of Mach numbers tested was noted. The drag was greater on the wrinkled sections than the smooth sections, however.

Note presenting the Izod-impact strengths and flexural properties of several types of plastic laminates, which are either in use or have potential application in aircraft structures and parts, and were determined at different temperatures. The materials investigated were unsaturated-polyester laminates reinforced with glass fabric and phenolic laminates reinforced with asbestos fabric, high-strength paper, rayon fabric, and cotton fabric.

From Summary: "A method of increasing the compressive strength of 24S-T aluminum-alloy sheet by flexure rolling was investigated. In this method, the sheet was alternately bent and then straightened by rolling a four-step procedure. The results showed that the greatest increase was in compressive yield stress in the with-grain direction regardless of the direction of rolling; the increase was greater as the radius of flexure rolling became smaller and as the number of steps was increased. The tensile properties, however, were little affected."

Report presenting the load capacities of four aluminum-alloy radial-engine crank-pin bearings determined in a centrifugal bearing test machine. Chemical analysis made after the bearings had been tested to failure showed that the actual composition of each aluminum alloy was different from the chemical specifications.

Monthly report documenting orders, opinions, and other legal statements issued by the Office of the Attorney General in Texas.

"Experiments by Deming at the Langley Memorial Aeronautical Laboratory confirm completely the formula of Gutin, which permits the convenient calculation of the sound level of any airplane propeller at low forward speeds. A simplification of the Gutin formula has been achieved by the use of a set of functions giving the sound level in the direction of maximum intensity. The sound level can be read from graphs of the functions for various numbers of blades and tip speeds. Two numerical examples and one experimental example are included; also, a radical fan-type propeller is tentatively treated" (p. 1).

Report presenting experiments to determine the shearing rigidity of curved panels under compression, particularly in that region of loading where the panels are in a buckled state. For the preliminary tests four, and for the final test series eight, circular cylinders were built of aluminum alloy sheet. Results regarding the uniformity of compressive strain, buckling of the panels, distribution of shear strain, calculation of the effective shear modulus, shear rigidity versus compressive strain curves, nondimensional shear rigidity curves, and failure of the cylinders are provided.

Note presenting three internally cooled exhaust valves with the same external dimensions but different throat designs were investigated to determine a method of obtaining increased coolant-flow area with increasing stresses. The valves were statistically loaded to simulate stresses in the throat region caused by valve closure.

"In the calculation of the dimensions of modern machines and building constructions, account is taken of the frequency of the occurrence of the anticipated loads. It is generally assumed that these loads will be repeated an infinite number, or at any rate some millions, of times during the total working life of the construction. When calculating the dimensions of the structural parts of aircraft, on the contrary, a consideration only of those frequencies in the appearance of the loads which actually come into play in the various states of stress is allowable" (p. 1).

Report presenting a two-dimensional wind tunnel investigation for the purpose of developing a suitable double slotted flap on a 14-percent-thick modified NACA 66-series-type airfoil section. Section aerodynamic characteristics of the airfoil with various double-slotted-flap arrangements are presented. Results regarding the airfoil with the flap retracted and flap deflected are provided.

Report presenting testing regarding the effectiveness of ducted head baffles in reducing temperatures of rear-row exhaust-valve seats using a two-row radial engine. Two types of ducted head baffle were investigated on a test stand and the better of the two was tested in flight. Results regarding the preliminary test stand investigation with two baffles and a flight investigation on five rear-row cylinders are provided.

Report discussing an investigation of the effect of variations in pitch distribution on propeller efficiency at low Mach numbers. The three 10-foot-diameter propellers tested consisted of three blades mounted on a streamline body and were tested for a blade-angle range from 15 degrees to 60 degrees. Information about the propeller thrust, power coefficients, force-balance measurements, and total pressure in the propeller wake is provided.

The weekly progress for D and F piles is given. Status of the test to determine the cause of white deposits on the horizontal control rods of the F pile is given. Also discussed are studies of process water control and pressure drop, corrosion, and graphite expansion. Test results indicate that graphite expansion has not seriously limited discharge of process tubes.

Abstract. A satisfactory method has been found for dissolving thorium metal and thorium oxide in heat-treated 25-12 stainless steel vessels without excessive corrosion of the vessels. The dissolution medium consists of strong HNO3 containing a small amount of fluoride or fluo-silicate. the fluoride required has no harmful effects on a subsequent solvent-extraction step for a separation of uranium isotopes from the dissolved thorium.