"The theoretical critical stress is derived for a simply supported curved rectangular panel in axial compression having a central chordwise stiffener offering no torsional restraint. The results are presented in the form of computed curves and a table. Because a panel of moderate or large curvature buckles in compression at a stress considerably below the theoretical value, a method is suggested to aid in determining the critical stress for use in design" (p. 1).

Report presenting an analysis of the factors determining the power efficiency of radiation thermopiles of the type in which receivers consist of parts of conducts themselves or of coatings or other electrically insulating materials in intimate contact with the conductors. Criterions for maximum power efficiency are calculated for these thermopiles, which can then be applied to general thermopile designs.

"Experimental data on the variation of the point unit thermal conductance in the entrance section of a circular tube are presented for 16 different flow conditions of the entering air. Results are compared with values calculated from existing analytical solutions. The average (integrated mean with length) unit thermal conductance is also calculated for eight entering-air conditions and is compared with values resulting from analytical methods" (p. 1).

Report presenting charts for calculating the quantity of hydrocarbon fuel required to attain a specific combustion temperature when water, alcohol, water-alcohol mixtures, liquid ammonia, liquid carbon dioxide, liquid nitrogen, liquid oxygen, or their mixtures are added to air as diluents or refrigerants.

Report presenting results of testing of 10 gages of each of 6 types of multistrand, single-element, bakelite-bonded wire strain gages. Some of the factors investigated included the uniformity of calibration factors for individual gages of the same type, variation of calibration factor with temperature, creep, effect of current on gage resistance, and variation in gage resistance with temperature.

Report presenting testing of six, 3-inch-chord symmetrical airfoil sections with systemic variations in thickness and maximum-thickness location at Mach numbers near flight values for propeller-shank sections. The tests were performed to illustrate the effects of compressibility on the flow past thick symmetrical airfoil sections. Results regarding flow characteristics and airfoil force characteristics are provided.

Report presenting a high-speed wind-tunnel investigation to determine the lateral-control characteristics of plug and retractable ailerons on a thin, low-drag, semispan wing equipped with a 25-percent-chord, full-span, slotted flap. The ailerons investigated covered 49 percent of the wing semispan, were located at 70-percent-chord station, and were perforated and segmented. Results regarding the wing aerodynamic characteristics, lateral-control characteristics with the plug aileron, lateral control characteristics with the retractable aileron, and a comparison of the characteristics are provided.

Report presenting an investigation of the hydrodynamic characteristics of a powered dynamic model of a hypothetical flying boat with a hull length-beam ratio of 9.0 in Langley tank no. 1. Results regarding trim limits of stability, center-of-gravity limits for stable take-off, landing stability, resistance, and spray characteristics are provided.

Report presenting an investigation to determine the influence of strength and ductility on the room-temperature burst characteristics of solid disks, disks with large-diameter central holes, and disks with small-diameter central holes. Results regarding the stress concentrations causing fracture, ratio of disk strength to tensile strength, effect of small holes, and evaluation of most ductile materials are provided.

Report presenting sound measurements for static conditions in a range of tip Mach numbers for three different dual-rotating-propeller configurations and one combination of two single-rotating propellers operating side by side in the same plane of rotation. The results obtained are compared with a theoretical analysis of the problem and excellent agreement is found.

Note presenting a device that measures the velocity of sound in fluids at stagnation and is especially adaptable to turbine and compressor testing for which the composition of the working fluid may be in doubt. The Helmholtz resonator is used for measuring sonic velocity and compressor Mach number in these devices.

Charts are provided for the estimation and progressive adjustment of two independent variables on which the calculations are based. Additional charts are provided for the graphical calculation of the composition.

Report presenting a method for calculating the pressures on aerodynamic shapes at very high supersonic speeds in dense air with the ratio of specific heats equal to 1. It is applicable to any body of revolution at zero angle of attack and to any two-dimensional profile. Some aerodynamic characteristics of several shapes are calculated, and lift and drag coefficients are shown to be dependent on thickness ratio, thickness distribution, and angle of attack.

Report presenting an investigation to determine whether three-dimensional flows may be efficiently utilized in axial-flow fan and compressor rotors. Two rotors, one with approximately uniform and one with solid-body downstream tangential-velocity distributions, were designed and tested at the designated blade angle. Results regarding the overall fan characteristics, surveys, and comparisons to theory are provided.

Note presenting a determination of the tensile and compressive properties of several types of plastic laminates, which are either in use or have potential application in aircraft structures and parts, at -70, 77, and 200 degrees Fahrenheit. The materials investigated were an unsaturated-polyester laminate with glass fabric as reinforcement and several phenolic laminates with asbestos fabric, high-strength paper, rayon fabric, and cotton fabric as reinforcements. Results regarding tensile properties at various temperatures, compressive properties at various temperatures, comparison of temperature dependence of flexural, tensile, and compressive properties, variation of strength properties of laminates with orientation of specimen, and strain at failure are provided.

Report presenting a low-speed wind-tunnel investigation to determine the effect of taper ratio on the static and yawing stability derivatives of three tapered wings with a constant sweepback of 45 degrees at the quarter-chord line and with an aspect ratio of 2.61 but different taper ratios. Results regarding the characteristics in straight flow and yawing flow are provided.

Report presenting testing of the low-speed aerodynamic characteristics of the NACA 66-series airfoil section in the two-dimensional low-turbulence pressure tunnel. Results regarding the critical-speed characteristics and low-speed characteristics are provided.

Note presenting an approximate method for calculating the pressure distribution on conical bodies of noncircular cross section in a supersonic flow field. By a superposition of elementary conical flows due to line sources, the flow about an arbitrary cone may be described.

Report presenting testing in the free-flight tunnel to determine the lateral stability, control, and general flying characteristics of a free-flying model with an unswept wing of aspect ratio 2. Testing occurred with a lift coefficient of 1.0 and covered a range of geometric dihedral angles and vertical-tail areas. Results regarding oscillatory stability, lateral control, and general flight behavior are provided.

Note presenting some results that have been obtained so far on ceramic coatings for molybdenum. The results indicated that the oxidation of the molybdenum was greatly retarded by the best of the ceramic coatings tried. Protection is possible in oxidizing atmospheres at gas temperatures up to 3500 degrees Fahrenheit.

Report presenting gust-tunnel testing to determine if gust-load factors for airplanes with low-drag wing sections should be higher than those for airplanes with conventional wing sections. A model with a wing with a low-drag section was used with smooth surfaces and with roughness applied to the leading edge to simulate the flow conditions for a conventional section.

Report presenting the use of x-ray diffraction methods to identify the minor phases present in 20 high-temperature alloys in current use. The minor phases were noted in seven of the 20 alloys. A description of the relation of the alloys to one another and their chemical properties are provided.

Note presenting an experimental investigation at low airspeeds of the filling effect observed when a screen or similar resistance is placed across a diffuser. The filling effect is found to be real in that screens can prevent separation or restore separated flow in diffusers even of extreme divergence and to depend principally on screen location and pressure-drop coefficient of the screen.

From Introduction: "In an incomprehensible medium, the mutual interference of a fuselage and wing of high-aspect ratio (to which lifting-line theory is applicable) has been treated by Lennertz, Wiselsberger, Pepper, and Multhopp in reference 1, 2, 3, and 4. It is the purpose of this note to treat the effect of on the aerodynamic loading of the mutual interference between a low-aspect-ratio pointed wing and a fuselage consisting of a slender body of revolution."