"In the present paper, under the same lineaeizing assumptions as are made in the derivation in reference 1 but with the explicit consideration and simplification of the form of the wake extending from the rear of the airfoil, the methods of Theodorsen (reference 2) have been extended to obtain the forces on the airfoil not only at a fixed angle of attack but also in arbitrary motion" (p. 1).

"The performance of the turbine component of an NACA research jet engine was investigated with cold air. The interaction and the matching of the turbine with the NACA eight-stage compressor were computed with the combination considered as a jet engine. The over-all performance of the engine was then determined. The internal aerodynamics were studied to the extent of investigating the performance of the first stator ring and its influence on the turbine performance" (p. 397).

"Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters. An adjustable speed governor was found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of preventing unstable burner operation during steady-state operation" (p. 1).

Abstract: The erroneously high values for uranium content of salvage solutions as determined by the ether extraction-ascorbic acid procedure have been demonstrated to be due to the presence of colored organic materials in these solutions. Evaporation of such solutions to fumes of HC104 before extraction has been shown to be completely successful in preventing such interference while pretreatment with activated carbon is sufficiently successful for application in Control laboratories. Complete procedures for application of either protreatment and results of such application to composite salvage solutions received over a six-month period are included.

Report issued by the U.S. Bureau of Mines on the sampling of chrome ore deposits in the western United States. Physical properties of the samples collected are presented. This report includes tables.

Abstract: A TEC regulator amplifier driving an Eaterline-Angus recording meter was used to record magnet current variations. Tests were made to determine magnet current variations. Tests were made to determine magnet current stability for currents from 500 amperes to 4000 amperes. Changes were necessary in both the TEC and GE regulators before currents below 2500 amperes could be regulated. Regulation to 0.025 percent for and hour was obtained for currents of 1000 to 4000 amperes with the TEC and GE regulators, and regulation to 0.05 percent for 500 ampere currents.

"A simple approximate method is given for the calculation of isentropic irrotational flows past symmetrical airfoils, including mixed subsonic-supersonic flows. The method is based on the choice of suitable values for the streamline curvature in the flow field and the subsequent integration of the equations of motion. The method yields limiting solutions for potential flow. The effect of circulation is considered" (p. 1).

"The problem of turbulence in aerodynamics is at present being attacked both theoretically and experimentally. In view of the fact however that purely theoretical considerations have not thus far led to satisfactory results the experimental treatment of the problem is of great importance. Among the different measuring procedures the hot wire methods are so far recognized as the most suitable for investigating the turbulence structure" (p. 1).

Report presenting a method for the calculation of the buckling stress of a multiweb wing in bending as well as design charts based on this method for the minimum-weight design of 24S-T aluminum alloy sheets, extruded 75S-T aluminum alloy, and extruded 0-1HTA magnesium alloy. An example of the use of the charts is also provided.

From Summary: "Three methods for calculating span load distribution, those developed by V.M Falkner, Wm. Mutterperl, and J. Weissinger, have been applied to five swept wings. The angles of sweep ranged from -45 degrees to +45 degrees. These methods were examined to establish their relative accuracy and case of application. Experimentally determined loadings were used as a basis for judging accuracy. For the convenience of the readers the computing forms and all information requisite to their application are included in appendixes. From the analysis it was found that the Weissinger method would be best suited to an over-all study of the effects of plan form on the span loading and associated characteristics of wings."

"It is known that compression shocks which lead from supersonic to subsonic velocity cause the flow to separate on impact on a rigid wall. Such shocks appear at bodies with circular symmetry or wing profiles on locally exceeding sonic velocity, and in Laval nozzles with too high a back pressure. The form of the compression shocks observed therein is investigated" (p. 1).

Note presenting a theoretical solution for the buckling stresses of long plates with transverse curvature loaded in shear and longitudinal direct stress. The theoretical critical-stress combinations for plates with either simply supported or clamped edges are given in figures and tables and a comparison is made with previous theoretical solutions. Results regarding the theoretical results, empirical results and design curves, and some interaction formulas are provided.

"A theoretical solution is presented for the determination of the combinations of direct axial stress and torsion which cause thin-walled cylinders with either simply supported or clamped edges to buckle. This theoretical solution is used in conjunction with available test data to develop empirical curves and formulas for use in design. Comparisons are made with theoretical and empirical solutions obtained in other investigations" (p. 1).

"A theoretical solution is presented for the buckling stress of long plates with transverse curvature loaded in shear. The results are given in the form of curves and formulas for plates with simply supported or clamped edges for a wide range of plate dimensions. Comparisons are made with theoretical solutions obtained in previous investigations" (p. 1).

"Empirical design curves are presented for the critical stress of thin-walled cylinders loaded in axial compression. These curves are plotted in terms of nondimensional parameters of small-deflection theory and are compared with theoretical curves derived for the buckling of cylinders with simply supported and clamped edges. An empirical equation is given for the buckling of cylinders having a length-radius ratio greater than about 0.75" (p. 1).

Note presenting a theoretical solution for the critical stress of thin-walled cylinders loaded in torsion. The results are presented in terms of simple formulas and curves which are applicable to a wide range of cylinder dimensions. The theoretical results are found to be in fairly good agreement with experimental results.

The crystal structures of alloys 61, X-40,X-50, 422-19, 6059, and Vitallium, derived from x-ray diffraction, are discussed. The alloys have been, or are being considered for use in gas turbine applications. The predominant phase was a solid solution of the face centered cubic type of the principal constituent elements.The lattice parameters were found to be between 3.5525 and 3.5662.

Report from the U.S. Bureau of Mines over the studies conducted on the Daisy mine and the Hillside mine in Hardin County, Illinois. Properties of the mines, and the types of mineral deposits found in each are presented. This report includes maps, and illustrations.

The Russian AM 35 and AM 38 aircraft engines have superchargers with a swirl throttle, which appears to be a purely Russian development. This paper gives the results of test runs of the two engines, including the effects of the swirl throttle on engine performance.

Note presenting an investigation to determine the reduction in drag that could be obtained for a conventional-type flying-boat hull by means of aerodynamic refinements. For comparisons, tests were made on a streamline body simulating the fuselage of a modern transport airplane.

Report presenting flutter tests of two wind-tunnel-fan models, one with conventional Clark Y airfoil sections and one with high-camber blade sections. The results indicated that higher flutter speeds were present for high lift coefficients for high-camber blades. Results regarding lift coefficients, blade-tip twisting, power loading, critical Mach numbers, flutter point, vibrational frequencies, and stall-flutter tip Mach number are provided.

Report presenting a review of literature to determine the frequency of sound of a given source strength that is loudest at various distances from the source. Frequencies in the range from 500 to 1000 cycles per second were found to be the easiest to hear, even at a distance of several miles. Sound data obtained from a light trainer airplane showed good agreement with predictions.

Report presenting an investigation in the free-spinning tunnel to determine the effect of horizontal-tail position on rudder hinge moments in simulated spinning conditions. Hinge-moment measurements were made on an unbalanced rudder on a rectangular vertical tail at six positions on the horizontal tail. Results regarding rudder hinge moments, tuft tests, and application of the hinge-moment data are provided.

Report presenting a wind-tunnel investigation to determine the effect of length-beam ratio on the aerodynamic characteristics of a family of flying-boat hulls in the presence of a wing. The hulls were designed to have approximately the same hydrodynamic performance with respect to spray and resistance characteristics. Results regarding the two-dimensional and three-dimensional mounting setups, drag reduction, and aerodynamic refinement effects are provided.