Report discusses the maximum lift coefficients for conventional and tailless airplanes in the gliding and landing conditions. Three areas are used to calculate the coefficients: wing area alone, wing area plus horizontal-tail area, and wing area plus horizontal- and vertical-tail areas.

"The determination of flight Mach number from measurements of indicated airspeed and pressure altitude is shown to be relatively simple and leads to direct and accurate computation of true airspeed. A simplified chart is presented for determining flight Mach number and true airspeed for a range of values of indicated airspeed, pressure altitude, and air temperature. A table of standard atmospheric values is included" (p. 1).

Report discussing the effects of supercharging on the take-off thrust and useful load for a typical helicopter. Performance of the engine with the supercharger and on the rotor thrust is detailed.

Report discussing an investigation of the knock-limited performance of triptane in F-3 and F-4 rating engines, two full-scale air-cooled aircraft cylinders, and flight tests on a full-scale multicylinder engine. Information about the lead susceptibility and effect of engine operating conditions is also provided.

Report discussing the results of testing to discover the effects of fuel-vapor loss on F-3 and F-4 knock-limited performance ratings and inspection properties of two aviation fuels, 28-R and 33-R. The percentage of loss at several temperatures, ability to meet Army-Navy fuel specifications, and antiknock rating change is described.

Report presenting a theoretical investigation of the buckling of an infinitely long flat plate with edges elastically restrained against rotation under combinations of longitudinal and transverse direct stress. Interaction curves are presented that give the critical combinations of stress for several different degrees of elastic edge restraint, including simple support and complete fixity.

"Tests of a 1/3-scale model of an NACA E-type cowling were made in the 8-foot high-speed tunnel for the purpose of determining the effect of the gap between the skirt of the hollow spinner and the cowling proper on the pressures available for cooling. It was found that even a large gap (0.096 in. on the model) had no appreciable effect on the available cooling pressures" (p. 1).

Report discusses an investigation into the tensile strength of cast-iron piston rings, NACA microtensile specimens, and bar specimens. Photographs showing the relation between graphite-flake size and tensile strength and radiographs showing the shrinkage cavities in the piston rings are provided. Piston rings tend to be one of the first parts of an aircraft engine to fail, so discovering the ideal material composition and foundry treatment is very important.

Report presenting a consideration of the performance of sliding surfaces, such as piston rings, cylinders, journals, and bearings in aircraft engines with reference to the surface characteristics that they possess before and after running-in, prior to service operation. The phenomena accompanying the running-in process are analyzed.

Report presenting a study of nitrided-steel piston rings in nitrided-steel cylinder barrels, which showed material of high reflectivity on their running faces. The structure of the material could not be resolved at a magnification of 1500 diameters. Results regarding the occurrence of coating, thickness of coating, height of coating above the nominal surface, chemical characteristics, physical characteristics, metallurgical change, and additional tests are provided.

Report presenting performance data on a small exhaust gas and air heat exchanger. The heat transfer rates were measured using about 8000 pounds per hour of exhaust gas and 4300 pounds per hour of ventilating air. The thermal performance of heater no. 2 can be estimated to 3 to 17 percent by use of the method described in the report.

Report presenting laboratory testing to determine the thermal output and pressure drop characteristics of the Airesearch and Solar fluted-type exhaust gas-air heat exchangers. The apparatus used in these tests consisted of a natural gas furnace of 3,000,000 Btu per hour thermal capacity, a centrifugal blower, and a system of ducting and various measuring devices. Results regarding the method of analysis, the Airesearch heat exchanger tests, the solar heat exchanger tests, and a comparison of the two heat exchangers are provided.

Report presenting a method of graphical analysis that allows for the prediction of the thermal and aerodynamic performance of a ram-operated heater and duct system, for cabin heating or wing de-icing, at any altitude and airplane speed. Performance can be predicted from the isothermal total pressure drop across the components of the duct system at several ventilating air rates and the thermal output of the heater at various air and exhaust gas rates.

Report presenting a study to determine the effect on the knock-limited permissible power output on the indicated specific fuel consumption and on the cylinder temperatures of exhaust-gas dilution of the inlet-air charge, inlet-air temperature without exhaust-gas dilation, and of compressible ratio.

Flow across tube banks was investigated by surveys of total dynamic and static pressure by visualization of the flow through the use of titanium tetrachloride smoke, by thermocouple surveys of heated tubes, and by hot-wire surveys of both heated and unheated tubes. It was found that turbulence increased as the depth of the bank increased and that the broad wake behind each tube affected flow over the succeeding tubes.

Report presenting variables that control the cooling of liquid-cooled and air-cooled engines and then to show by illustrations how either engine may be cooled at any desired altitude. Cooling was found to not be the limiting factor in the design of high-altitude airplanes and was also not found to be a valid reason for selecting either liquid- or air-cooled engines for high-altitude operation.

Report discussing testing of a model of the Kaiser tailless airplane in order to determine its general aerodynamic characteristics and the probable stability and control characteristics. Only the results of the tests are presented in this report; the estimated flying qualities are in a separate report. Information about the lift, stall, drag, elevator effectiveness and hinge moments, rudder effectiveness and hinge moments, aileron effectiveness and hinge moments, and characteristics in yaw is included.

Report discussing an investigation of wing-inlet oil-cooler ducts on a twin-engine airplane to determine internal and external-flow characteristics of the ducting installation. Testing was also performed on revised inlets to attempt to develop a ducting system with low overall losses throughout the operating range.

Report presenting tests to verify and extend ultraviolet spectroscopic techniques for applications to the analysis of aviation fuels for their aromatic constituents. Results regarding photographic absorption spectra, spectrophotometric absorption spectra, and spectrophotometric analyses are provided.

Report presenting testing of a Fairchild XR2K-1 airplane equipped with a wing having a full-span Zap flap and upper-surface ailerons in the full-scale wind tunnel and in flight to determine the characteristics of the flap and ailerons. Results regarding the lift, drag, and pitching-moment coefficients of the airplane and the aileron rolling, yawing, and hinge-moment coefficients were measured at various flap deflections are provided. Maximum rolling velocity and acceleration, yawing velocity, time lag in aileron response, and aileron control forces were also determined.

Report presenting an investigation of the pressure-drop characteristics of orifice plates, which has been conducted to facilitate the design of resistances to simulate various types of cooling units. This use of the orifice plates was found to be practical because of the simple construction of the plates, the ease of which pressure drop can be varied by use of corks, and the absence of any large scale effects.

Report discussing tests of a Sikorsky YR-4B helicopter, including photography of a rotor blade in forward-flight conditions at several azimuth angles for several tip-speed ratios. Fabric deformation in the form of sagging and bulging was noted. A reversal in the bending curve near the blade tip was also noted, which was hypothesized to come from losses of lift and high centrifugal force.

"Tests were conducted to develop a slip-ring and brush system that will perform satisfactorily in aircraft-engine, dynamic-strain-measuring applications where resistance-wire strain gages are the means of measuring the strain and to correlate the data obtained from tests in order to provide a basis for predicting the performance of similar slip-ring and brush systems operating under conditions similar to those imposed by these tests." 24 combinations of materials were tested dry and 8 were tested in oil. The five most predictable systems were identified.

Report presenting an investigation conducted with the propeller cuffs and spinner removed to determine their effect in flight on the pressure recovery of the cooling-air flow. Curves are presented to compare the pressure and temperature distribution over the front row of cylinders for flights with and without cuffs and spinner.