Memorandum presenting an investigation conducted to evaluate the effectiveness of a simple internal regenerative fuel preheater for a 20-inch-diameter ram jet. Data obtained at subsonic sea-level conditions indicated that fuel could be successfully preheated in this manner.

Report presenting a preliminary theoretical and experimental investigation of the supersonic characteristics of blunt-trailing-edge airfoils. Results regarding the drag measurements at zero lift, measurements at angle of attack, and a general discussion of the theoretical and experimental results is provided.

By use of the assumption that the pressure-volume relation is linear, a solution to the problem of designing a cascade for a given turning and with a prescribed velocity distribution along the blade in a potential flow of a compressible perfect fluid was obtained by a method of correspondence between potential flows of compressible and incompressible fluids. The designing of an isolated airfoil with a prescribed velocity distribution along the airfoil is considered as a special case of cascade. If the prescribed velocity distribution is not theoretically attainable, the method provides a means of modifying the distribution so as to obtain a physically significant blade shape. Numerical examples are included.

Report discussing a wing-alone and wing-fuselage configuration with particular characteristics as part of a series of tests of wings using the transonic-bump test technique. Lift, drag, pitching moment, and root bending moment were obtained for the configurations. The effective downwash angles and dynamic-pressure characteristics in the tail region are also described.

A report discussing a method of computing the critical mass of U₂₃₅ contained in a water solution confined to a spherical core and surrounded by an infinite water tamper, a modification of said method in which the effect of the resonance fission and absorption is taken into account, and physical constants required to calculate the critical mass using these methods.

Introduction: In order to determine the relative corrosion resistance of welded mild and stainless steels in Redox Stream IAW neutralized to pH 0, 2, and 10 a test program, described below, has been carried out.

"Methods are presented that use general correlative time-response input and output data for a linear system to determine the frequency-response function of that system. These methods give an exact description of any linear system for which such transient data are available. Examples are shown of application of a method to both an underdamped and a critically damped exact second-order system, and to an exact first-order system with and without dead time. Experimental data for a turbine-propeller engine showing the response of engine speed to change in propeller-blade angle are presented and analyzed" (p. 547).

Report presenting the results of an experimental investigation to determine the pressure-recovery and mass-flow characteristics of single and twin NACA submerged intakes on the sides of a fuselage at various angles of sideslip. Tests were conducted with single and twin submerged intakes on a model of a fighter-type airplane.

From summary: "A method for the preparation of normal uranyl carbonate has been developed. Heretofore, this compound has been known only as a rare, naturally occurring material." The report further discusses the physical properties of the compound, its solubility in water, and its interaction with sodium carbonate.

The following report is a quarterly report by the Monsanto Chemical Company for liquid waste disposal research, covering the period between April 1 to June 30, 1949.

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.

Abstract: "A method is described for the identification and quantitative determination of trace amounts of rare earths in graphite by measurement of the energies and decays of the activities induced by neutron irradiation. The specific rare earth elements identified are europium and samarium. During the development of this method, the half-lives of Eu-152 and Sm-153 were determined. These are reported as 9.32 +/- 0.04 hours and 46.34 +/- 0.23 respectively."

"An investigation was conducted on a turbulent boundary layer near a smooth surface with pressure gradients sufficient to cause flow separation. The Reynolds number was high, but the speeds were entirely within the incompressible flow range. The investigation consisted of measurements of mean flow, three components of turbulence intensity, turbulent shearing stress, and correlations between two fluctuation components at a point and between the same component of different points" (p. 1).

Fundamental principles and techniques used for voltage measurements primarily for frequencies in the upper audio- and radio-frequency ranges and including part of the ultrahigh frequency range.

Report presenting an investigation of the effect of two wing sections and a tip tank on the aerodynamic characteristics of a rigid unswept wing in the high-speed tunnel over a Mach number range of 0.60 to 0.90. Results regarding the effect of original airfoil sections, effect of modifications to Section B, effect of tip tank, and characteristics of the tip tank in the presence of the wing are provided.

Report presenting the results of an experimental investigation of rim cracking in a welded-blade composite gas-turbine wheel, in two carbon-steel disks, and five tool-steel disks. Various characteristics were investigated, including the effectiveness of holes in preventing crack propagation and the influence of hardness and various types of notch on rim cracking.

"Basic general equations governing the three-dimensional compressible flow of gas through a compressor or turbine are given in terms of total enthalpy, entropy, and velocity components of the gas. Two methods of solution are obtained for the simplified, steady axially symmetric flow; one involves the use of a number of successive planes normal to the axis of the machine and short distances apart, and the other involves only three stations for a stage in which an appropriate radial-flow path is used. Methods of calculation for the limiting cases of zero and infinite blade aspect ratios and an approximate method of calculation for finite blade aspect ratio are also given" (p. 1).