From Introduction: "Certain alternations of a qualitative nature may be performed in spite of the fact that a pressure change cannot be prescribed. It is the purpose of this paper to indicate a method by which qualitative alternation may be performed. It will be noted that the present method of contour modification will serve the intended purpose of the inverse method."

"A solution of Von Karman's fundamental equations for plates with large deflections is presented for the case of a shear web divided into square panels by reinforcing struts. Numerical solutions are given for struts of infinite rigidity and for struts the weight of which is one-fourth the weight of the sheet. The results are compared with Wagner's diagonal tension theory as extended by Kuhn and by Langhaar. It is found that the diagonal tension theory as developed by Kuhn agrees best with the present paper in the practical range when r=1/4. Kuhn's theory is in especially good agreement for the force in the strut when r=1/4" (p. 1).

"A systematic account is given in part I of the use of dimensional analysis in constructing similarity conditions for models and structures. The analysis covers large deflections, buckling, plastic behavior, and materials with nonlinear stress-strain characteristics, as well as the simpler structural problems" (p. 1).

Technical report abstract. The present state of knowledge concerning the effect of pile radiation on a variety of solid materials is reviewed. Radiation corrosion will not be a serious hazard for aluminum or stainless steel but it can be for iron or lead if either are exposed to water. Apart from corrosion the principal uncertainty is in regard to the Wigner effect on the behavior of metals. There is at present no ground for optimism regarding the behavior of tuballoy. The effect on aluminum or a bonding material while less severe must also be considered serious. The expectation in regard to graphite is that its behavior will not cause trouble during the first 100 days of operation although serious troubles will probably arise within two years of operation. Organic materials can be used safely only in regions of limited exposure.

Report presenting testing to obtain experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. Testing occurred over a wide range of air flows and density altitudes.

"Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multicylinder engines. Tests were conducted over a wide range of air flows and density altitudes" (p. 1).

"Theoretical investigations have shown that, because air is compressible, the pressure-drop requirements for cooling an air-cooled engine will be much greater at high altitudes and high speeds than at sea level and low speeds. Tests were conducted by the NACA to obtain some experimental confirmation of the effect of air compressibility on cooling and pressure loss of a baffled cylinder barrel and to evaluate various methods of analysis. The results reported in the present paper are regarded as preliminary to tests on single-cylinder and multi-cylinder engines. Tests were conducted over a wide range of air flows and density altitudes" (p. 185).

Technical report describing the investigation of the short-lived activities produced in oxygen compounds by irradiation with pile neutrons. The most prominent of these activities in cooling water is a beta and gamma emitting activity of about 8 second half-life. Because of its production by epicadmium neutrons it was believed to be the 8 second N16 produced in the pile by n,p on O16. The identification has been accomplished and it is established that the 8 second activity is N16. Part 2 of the report deals with the determination of the recoil range of the Al28 atoms formed by pile n,p reaction on Al27.

Pressure distribution measurements were made over an airfoil with slotted Frise aileron up to 0.76 Mach at various angles of attack and aileron defections. Section characteristics were determined from these pressure data. Results indicated loss of aileron rolling power for deflections ranging from -12 Degrees to -19 Degrees.

Report presenting an analysis of the effect of cooling-air blowers on thrust power using an assumed airplane. Results indicated that when aviation-engine heat exchangers are used above their design altitude, blowers may be used to give additional available pressure and to increase jet thrust. Results regarding airplane speed, altitude, fin width, physical significance of the heat cycle, and thermodynamic efficiency are provided.

Report presenting a method of constructing fins of nearly optimum proportions to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. Results regarding cooling equations, cylinder-temperature relationships, and a comparison of three cylinder cooling performances are provided.

A method of constructing fins of nearly optimum proportions has been developed by the NACA to the point where a cylinder has been manufactured and tested. Data were obtained on cylinder temperature for a wide range of inlet-manifold pressures, engine speeds, and cooling-pressure differences. The results indicate that an improvement of 40 percent in the outside-wall heat-transfer coefficient could be realized on the present NACA cylinder by providing a thermal bond equivalent to that of an integral fin-cylinder wall combination between the preformed fins and the cast cylinder wall" (p. 107).

To determine the effect of piston-head temperature on knock-limited power, tests were made in a supercharged CFR engine over a range of fuel-air ratios from 0.055 to 0.120, using S-3 reference fuel, AN-F-28, Amendment-2, aviation gasoline, and AN-F-28 plus 2 percent xylidines by weight. Tests were run at a compression ratio of 7.0 with inlet-air temperatures of 150 F and 250 F and at a compression ratio of 8.0 with an inlet-air temperature of 250 F. All other engine conditions were held constant.

Technical report. Long-time tests have been made on the effect of various types of radiation on the corrosion of 2S aluminum in simulated W water. In no case was any acceleration of corrosion by the radiation observed; the effect of radiation, if any, appeared to be a protective one. Deuteron irradiation did accelerate the corrosion of mild steel at low flow rates in hot water of pH 6 to 7, but no appreciable effect was observed with copper, stainless steel, or tuballoy. The general theory of the effect of radiation on corrosion is discussed, with the conclusion that no acceleration of corrosion by radiation is to be expected in most cases of practical interest.

Report presenting the use of current methods that include interference and compressibility effects to estimate pressures over and near turrets located on a wing in regions of high interference velocities. The agreement between measured and estimated pressures indicated that present methods are adequate for predicting approximate critical speeds and for estimating loads at subcritical speeds with sufficient accuracy for design purposes.

Various experimenters have shown (H.H. Gersman U.S. Patent 2,335,590, Nov. 30, 1943; Aluminum Co. of America, various technical papers; also CT-482) that when a billet is extruded by proper technique into a rod (or tube by a floating mandril) that flow of material is streamline and and the extruded article is essentially a space replica of the billet, with linearly distorted coordinates. Advantage is taken of this fact in the manufacture of alclad tubing in which a billet containing an inner core of one alloy with the outer part of another alloy cast around it is extruded together into an integral tube, e.g., to combine high corrosion resistance with high strength. The following experiments were carried out because of the desirability of obtaining a control rod which can be water cooled (or immersed in P9) and which contains boron. For some pile structures it may be desirable to have the major portion of the energy released by the neutron absorption of the control rod be spend in the rod itself by the nuclear reactions [formula] rather than in the surrounding media as is the case when absorption of neutrons is by cadmium according to the reaction [formula]. In the later …

Report presenting a series of tests on the Brewster XSBA-1 airplane to determine the effects of various tail modifications. Some of the modifications include variations of the chord of the elevator and rudder while the span and total area of the surfaces are kept constant and variations of the total area of the vertical tail surface. Results regarding the longitudinal stability and control and lateral stability and control are provided.

"The Ackeret iteration process is utilized to obtain higher approximations than that of Prandtl and Glauert for the flow of a compressible fluid past a circular arc profile. The procedure is to expand the velocity potential in a power series of the camber coefficient. The first two terms of the development correspond to the Prandtl-Glauert approximation and yield the well-known correction to the circulation about the profile" (p. 385).

Technical report. The effect of temperature during pile exposure on the fast-neutron-induced change in properties of graphite was studied. Temperatures up to 125 degrees C have no effect upon the rate of increase of elastic modulus; pieces exposed at 300 degrees C on the other hand show no change at all in elastic modulus. The increase in electrical resistance s an inverse function of the temperature of exposure at all temperatures in the range 60 to 300 degrees C.

From Summary: "The application of the well-known basic principle of mechanics, the principle of Jourdain, to problems of the theory of the boundary layer leads to an equation from which the equations of Von Karman, Leibenson, and Golubev are derived as special cases. The given equation may be employed in other integral methods. The present paper deals with the method of the variation of the thickness of the boundary layer. A number of new approximate formulas valuable in aerodynamic calculations for the friction distribution are derived from this procedure. The method has been applied only to laminar boundary layers, but it seems probable that it may be generalized to include turbulent layers as well."

Bulletin presenting an investigation of the effects of various camouflage paints and painting procedures on the drag characteristics of a 60-inch-chord low-drag airfoil in the NACA two-dimensional low-turbulence pressure tunnel.

Report presenting investigations to determine the knock-limited performance of blends of 90 percent by volume AN-F-28, Amendment-2 fuel, and 10 percent by volume of the following fuels: tert-amyl alcohol, 2,6-dimethyl-1, 4-dioxane, methyl tert-butyl ether, methyl tert-butyl ketone, methyl isobutyl ketone, mesityl oxide, acetone, and diisopropyl ketone.

Technical report with short reports on (1) P-9 recovery from UO2F2 solution; (2) Correlation of theories on action of radiation on matter; (3) Literature surveys on organic compounds and on chemistry of UO2F2; (4) effect of radiation on organic compounds; and (5) Effect of radiation on 100 area construction materials.

"An analysis is developed that makes it possible to integrate von Kármán's boundary-layer momentum equation directly. For this purpose, the skin friction coefficient is expressed as a function of the Reynolds number based on the boundary-layer momentum thickness and the boundary-layer shape is assumed to be constant. The integrated equation permits the boundary-layer momentum thickness at the airfoil trailing edge to be rapidly determined for the estimation of airfoil profile-drag coefficients" (p .1).