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.

Report presenting tests of a partial-span model of a large bomber-type airplane, which were conducted to provide data on the aerodynamic characteristics of the aileron-tab arrangement and of the wing. Testing occurred to determine the rolling-moment, yawing-moment, and hinge-moment characteristics of the aileron and tab and the effect of midchord wing slots on the characteristics of the wing and aileron and tab. Results regarding the aerodynamic and stalling characteristics of the wing and aerodynamic characteristics of the aileron and tab are provided.

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.

"This is the sixth of a series of reports covering an investigation of the general instability problem by the California Institute of Technology. This report and the succeeding reports of this series cover the work done on other loading conditions under the sponsorship of the National Advisory Committee for Aeronautics. This report summarizes the work that has been carried on in the experimental investigation of the problem of general instability of stiffened metal cylinders subjected to combined bending and transverse shear at the C.I.T." (p. 1).

Note presenting measurements of the vertical distribution of liquid water concentration and drop size made in winter stratus clouds in the absence of significant cyclonic or frontal activity. The observations indicate that the clouds are formed by turbulent mixing of the lower layers of the atmosphere, resulting in a region of constant specific humidity and adiabatic lapse rates.

Report presenting a study of the factors influencing the performance of aerodynamic brakes. The increases in drag coefficient that are characteristics of several types of wing and fuselage aerodynamic brakes, which have been tested in wind tunnels or in flight, are summarized in the report.

Report presenting an experimental investigation to determine the orifice coefficient of a jet direct perpendicularly to an air stream as a function of pressure ratio and jet Reynolds number for circular, square, and elliptical orifices. The effect of air-stream velocity on the jet flow was also determined for three tunnel-air velocities.

Report presenting an investigation of a turbine and propeller to determine the conditions of maximum-efficiency operation when utilized as an independent turbine-propeller combination. The procedure used to determine the conditions of maximum efficiency and speed ratio between the turbine and propeller is described.

From Introduction: "The flare assumed is based primarily on reference 1, in which information permitting calculation of the flare characteristics of an airplane was obtained from flight tests. The results of calculations for airplanes having constant lift-drag ratio during the flare are plotted in chart form."

Report presenting an analysis of wind-tunnel data for two types of lateral-control system for large airplanes in order to determine the control-force characteristics and rolling effectiveness of each system. The two types of control systems explored are a spring-tab aileron and a combination spoiler and guide or pilot-aileron arrangement.

"Panels of aluminum alloy sheets, framed by side and end stiffeners, were subjected to combined loading by means of offset knife edges applying loads to top and bottom end plates with reacting forces against the end plates supplied by laterally acting rollers. The test specimens were 17S-T aluminum alloy shoots 0.040 inch thick in panels of 10-inch width and three different lengths (approximately 10, 26, and 30 inch). Data were obtained for the bowing of transverse and longitudinal ribs of rectangular cross section and varying depths mounted on one side of the sheet only, for several ratios of compression to shear loads" (p. 1).

Report presenting results for a part of a test program on 24S-T aluminum-alloy flat compression panels with longitudinal formed hat-section stiffeners. This particular part of the program is concerned with panels in which the thickness of the stiffener material is equal to the thickness of the skin. Results regarding the hat-stiffened panels and a comparison of hat-stiffened and Z-stiffened panels are provided.

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 a study to determine the nature of the surfaces formed on hardened steel parts during rubbing, notably on piston rings and cylinders during run-in. The technique of measuring the small amounts of material transferred from one rubbing surface to another by making one radioactive is applied to hardened steel surfaces, both nitrided and non-nitrided, and to chromium-plated steel.

Eighteen 24S-T alclad cylinders of 20-inch diameter, with skin thickness varying between 0.012 inch and 0.025 inch and length varying between 40.5 inches and 64 inches, were tested in pure bending. They were reinforced with either 16 or 28 stringers and either 5 or 6 rings. One of the purposes of the investigation was to establish the critical value above which failure would occur by general instability and below which panel instability would take place. This value was found to be between 20 and 40 for cylinders with 16 stringers and between 16 and 74 for cylinders with 28 stringers.

Note presenting an investigation of the effect of flow conditions on the geometry of the turbulent Bunsen flame. Data are presented showing the effect of Reynolds number of flow in the range of 3000 to 35,000 on flame speed for burner diameters from 1/8 to 1 1/8 inches and three fuels - acetylene, ethylene, and propane. Results regarding the geometry of the turbulent Bunsen flames, turbulent flame speeds, nature of turbulence in pipe flow, theories of turbulent flame speed, and the nature of variation of turbulent-flame speed are provided.

Report exploring the use of the Busemann third-order approximation for two-dimensional isentropic flow used in suitable conjunction with three-dimensional solutions found by the linearized theory to determine analytically, for small angles of attack and control deflections, the control-surface characteristics of partial-span constant-chord flaps on rectangular wings having finite thickness. Equations are provided for lift coefficient, rolling-moment coefficient, and hinge-moment coefficient due to control deflection, and for pitching-moment coefficient due to flap lift.

Note presenting an investigation of the weight of a simply supported transversely stiffened compression panel subjected to a given buckling load as a function of the stiffener spacing, plate thickness, and the geometry of the stiffener cross section. Results indicate that there are particular combinations of stiffener spacing and plate thickness, dependent on the geometrical properties of the stiffener cross section, for which the panel weight is a minimum.

"A matrix method of determining transmission, scattering, and absorption of radiation, such as gamma rays and neutrons, in large thickness of matter is presented. Experimental data as yet unavailable are required for complete utilization of the method. Material radioactivity whose intensity may be considered to be independent of time is also treated" (p. 1).