Note presenting an analysis of the use of the Prandtl-Glauert method for subsonic potential flow of a compressible fluid. This paper specifically focuses on the difference between the two- and three-dimensional flow when using this method.

Note presenting a well-known method of generating stream functions of an incompressible fluid flow, which involves taking the imaginary part of an analytic function of a complex variable. This paper is specifically devoted to a detailed discussion of performing computations related to obtaining flow patterns of compressible fluid from analytic functions of a compressible fluid. An example is also provided to illustrate the method.

Report presenting preignition-limited performance data for S reference fuel, diisobutylene, and benzene with an engine-heated hot spot on a supercharged CFR engine at 11 sets of engine operating conditions. Results indicated that increases in compression ratio, spark advance, coolant temperature, or inlet-air temperature decreased the preignition-limited indicated mean effective pressure of all three fuels.

Note presenting a study of the altered surface layers found on nitrided-steel piston rings run in nitrided-steel cylinder barrels in order to determine the physical and chemical characteristics of the altered layers and the mechanism by which the coating layers were formed. An electron and a light microscope were used to study different aspects of the materials.

Note presenting an investigation of the stability of two-dimensional laminar flows of a gas by the method of small perturbations. The chief emphasis is placed on the case of the laminar boundary layer.

Note presenting the application of the equations of the theory of rate processes to stress rupture in order to predict the experimental stress and temperature dependence of the time for rupture for three heat-resisting alloys. Results regarding stress dependence, temperature dependence of slope factor, and temperature dependence of apparent free energy of activation are provided.

Technical report that attempts to bring together the various chemical procedures which proved most useful in studying the results of cyclotron bombardment or small scale neutron bombardments of heavy element targets. The report is limited to the elements of the "actinide", or second rare earth series, starting with thorium and including the newly discovered elements of atomic number 95 and 96. Every attempt is made to include all details necessary so this report can serve as a practical laboratory guide. The report covers separation problems, time factors, and dealing with dangerously radioactive targets.

Abstract: "The results obtained from the tests conducted for the purpose of determining the corrosivity of a 30 percent-solution of uranyl fluoride to various metals indicate that stainless steels (type 302, 304, 321 and 316) have very good resistance; while monel, nickel and aluminum, respectively, exhibit diminishing resistance. Stainless steel, type 316, was the most resistant of the specimen tested."

Report discussing trial runs of a method of recovery of uranium from salvage residue. The method involves hydrofluorination of the residue to remove large quantities of interfering silicates, followed by a fluorination treatment to remove uranium.

Report presenting testing in high-speed flight with a fighter airplane to determine the effect of chordwise pressure distribution resulting from a minor modification in the contour of the wing upper surface. A faired bulge was added to the contour and chordwise pressure distributions were obtained on the original and modified contours.

Report presenting rupture tests of two precision-cast alloys at 1700 and 1800 degrees Fahrenheit. The results indicate that the NT-2 type alloy was stronger than the VT2-2 type alloy for time periods longer than 10 hours. Results regarding a correlation of results and curves of stress against log rupture time are provided.

Note presenting symbols and definitions of various airspeed terms that have been adopted as standard by the NACA Subcommittee on Aircraft Structural Design. the equations, charts, and tables required in the evaluation of true airspeed, calibrated airspeed, equivalent airspeed, impact and dynamic pressures, and Mach and Reynolds numbers have been compiled.

Report presenting the use of thin-airfoil theory on oblique or sweptback airfoils of finite aspect ratio moving at supersonic speeds. In the case of untapered airfoils swept back behind the Mach cone, the pressure distribution at the center section is similar to that given by the Ackeret theory for a straight airfoil.

From Introduction: "The present report is the second prepared to give the results of an analysis of V-G data from commercial transport airplanes. The present report is concerned with an analysis of data obtained with Douglas DC-3 airplanes flying over three transcontinental routes in the United States."

Note presenting a theoretical investigation undertaken to evaluate the effect of small deviations from flatness on the behavior of simply supported square plates under compression, it being assumed that the proportional limit is not exceeded. Results regarding the growth of buckles with increase in load, effective width of plate, experimentally defined buckling or critical stress, critical stress and postbuckling behavior of the plate, and the Southwell plot method of predicting theoretical critical stress are provided.

"An extensive series of tests were conducted on riveted joints to determine the effect of rivet size and rivet pitch on the fatigue lift of joints subjected to "prying" (combined tensile and bending) loads. For each sheet thickness tested, there appeared to be a value of the ratio of rivet pitch to rivet diameter that would ensure a near maximum of the ratio of fatigue strength to static ultimate strength for the joint" (p. 1).

"In order to establish a standard procedure for rating and testing multistage axial-flow compressors, the NACA Subcomittee on Compressors appointed a panel to write such a procedure. This panel made recommendations for standardization of test setups, instrumentation, test procedure, data to be taken, and the presentation of the data. These recommendations are presented" (p. 1).

Report presenting an investigation of a series of landings made with a large bomber-type airplane equipped with twin vertical tails to determine the time history of the impact forces on the landing gear and the resulting response of the airplane structure, especially the horizontal tail, to the landing loads. About 50 landings were made of various types, but complete time histories were only obtained for 23 landings. Results regarding tabulation of landings, velocity at contact, landing-gear loads, effect of braking on landing-gear loads, effect of prerotation on landing-gear loads, structural response to impact loads, and analysis of separate effects of impact parameters are provided.

From Introduction: "The present paper has been prepared to give the results of the analysis of the V-G records obtained from three Boeing S-307 airplanes operating in Caribbean region and the northern part of South America during the period from 1940 to 1944."

Report presenting a mathematical analysis of the effect of misalignment among the components of rectangular and equiangular strain rosettes on the determination of the magnitudes and directions of principal strains. Misalignments of 2 degrees among individual gases introduced serious errors in the computation of principal strains from rosette data.

Report presenting aerodynamic, rain, and icing tests on the standard carburetor air scoop of a large twin-engine cargo airplane and several under-cowling scoops designed to eliminate the ram-pressure loss accompanying impact icing of a standard scoop and carburetor screen. Testing was performed at several angles of attack, charge-air flows, and cooling-air flows.

Note presenting a system for calculating the physical properties of supersonic rotational flow with axial symmetry and supersonic rotational flow in a two-dimensional field as determined by use of the characteristics method. Practical use of the system is based on a step-by-step procedure that requires long numerical calculations. Some applications were made to determine the external and internal flow on bodies of revolution with axial symmetry.

Note presenting tests at high speeds to determine the drag of models, simulating propeller shanks, in the form of a circular cylinder and three airfoils with the rear 25 percent chord cut off. The results indicated that the drag of the airfoils was lower than that of the cylinder over the Mach number range investigated.

Report presenting testing of a model of a single-engine low-wing airplane with three propeller-blade settings and three values of tail length to provide information on the effects of slipstream rotation on the directional stability and control characteristics. Results regarding the comparison of computed and measured coefficients and stability are provided.