From Summary: "A method for the experimental determination of the rate of infiltration of air into aircraft cabins during flight has been developed and tested. This method consists of releasing a quantity of gas in the cabin and calculating the infiltration rate from the measured rate of change of the gas concentration. The results of the flight tests indicate that after the infiltration rate is established at one altitude and airspeed, the infiltration rates at other altitudes and airspeeds can be calculated."

Report presenting an investigation of elevators with three hinges to evaluate the structural hinge-moment increments resulting from changing the elevator angle when the hinge axis is distorted under load. The analytical results are compared to test data obtained for a full-scale semispan fighter-type horizontal tail surface in the 16-foot high-speed tunnel.

Note presenting an equation for the steady-state rate of creep, which has been derived by applying the theory of dislocations to the creep of pure metals. The form of this equation is in good agreement with empirical equations describing creep rates. A discussion of the way the theory can be applied to alloys, in particular heat-resisting alloys, is also provided.

A vertical-tail model with stub fuselage was tested in combination with various simulated horizontal tails to determine the effect of horizontal-tail span and location on the aerodynamic characteristics of the vertical tail. Available theoretical data on end-plate effects were collected and presented in the form most suitable for design purposes. Reasonable agreement was obtained between the measured and theoretical end-plate effects of horizontal tails on vertical tails, and the data indicated that the end-plate effect was determined more by the location of the horizontal tail than by the span of the horizontal tail. The horizontal tail gave most end-plate effect when located near either tip of the vertical tail and, when located near the base of the vertical tail, the end-plate effect was increased by moving the horizontal tail rearward.

Report presenting a study of accurate values of the specific heat for dry air applied to the calculation of work required to compress dry air. Two charts are provided that allow the work of compression to be determined from the initial temperature, overall pressure ratio, and either the compression exponent or adiabatic efficiency of the compressor.

Report presenting testing on a wire strain gage of representative design to determine zero shift after straining at room temperature, error in indicated strains at high and low temperature, and changes in calibration factor and zero shift after exposure to heavy weathering. Results regarding the measurements of zero shift after 1 to 10 cycles of straining and testing to determine whether or not zero shift was removed by prestraining reappeared after the gages were left unstrained are provided.

Note presenting an analysis of the relative distribution of mass along the wings and fuselage and the relative density of the airplane as well as the design of vertical surfaces when determining design requirements for aircraft tail surfaces. A chart is presented that shows an empirical relationship between a tail-damping power factor and the relative density and mass distribution for satisfactory spin recovery.

Note presenting tests conducted on untapered constant-span wings of 0, 30, 45, and 60 degrees sweepback. The purpose of the tests was to investigate the effect of sweepback on stability and control characteristics. The data showed large changes in longitudinal stability at moderate lift coefficients for the 45 and 60 degree sweptback wings.

Note presenting the results of a preliminary study of combustion in flowing gases and apparatus for obtaining high rates of heat release per unit volume of combustion space are described. Tests were made over a wide range of fuel-air ratios, inlet-mixture velocities, and electrical heat inputs, using propane gas as the fuel. Results indicate that the greater the surface-volume ratio, or the greater the amount of heat addible to the gas stream, the greater the inlet-mixture velocity at which appreciable combustion can be obtained.

Note presenting a fixture for compressive tests of thin sheet metal. It consists of two hardened steel guides between which the specimen is held by two adjustable clamps. Results and analysis regarding steel versus brass guides, the lubricant film, tests without the subpress, and comparison of tensile tests with compressive tests using steel guides are provided.

Report presenting an experimental method of measuring both the arithmetic mean velocity and the instantaneous velocity of pulsating flow and with the instruments developed for this purpose. A circuit for a hot-wire anemometer usable for fluctuating flow is described.

Report presenting a two-dimensional wind-tunnel investigation of three low-drag airfoil sections equipped with sealed internally balanced control surfaces designed for use as vertical-tail, horizontal-tail, and wing sections. Testing included determination of control-surface effectiveness and hinge moments and airfoil section drag characteristics. Results regarding vertical-tail section, horizontal-tail section, wing section, and effect of sudden movement of transition on airplane control-surface characteristics are provided.

"This report deals with the calculation of the bending moments in and the distortions of fuselage rings upon which known concentrated and distributed loads are acting. In the procedure suggested, the ring is divided into a number of beams each having a constant radius of curvature. The forces and moments caused in the end sections of the beams by individual unit displacements of the end sections are listed in a table designated as the operations table in conformity with Southwell's nomenclature. The operations table and the external loads are equivalent to a set of linear equations" (p. 1).

"Formulas for the calculation of influence coefficients of curved beams of constant radius of curvature are presented corresponding to displacements in the plane of curvature. Moreover, numerical values are given in tabular and graphic form for a limited number of values of the parameter involved" (p. 1).

"As a first step toward the computation of the velocity distribution along a wing profile of arbitrary shape in a compressible fluid, the circulation-free flow around a symmetrical profile is treated under the assumption of the simplified density-speed relation due to Tchaplygin, Karman, and Tsien. The velocity distribution problem is reduced to a non-linear integral equation which is solved by a fairly rapidly convergent iteration method. Numerical examples are given" (p. 1).