Report presenting pressure-distribution measurements made in steady straight and accelerated flight over a horizontal tail surface of a typical pursuit airplane. Results regarding the variation of horizontal-tail loads with Mach number, variation of root bending moments and fuselage torsional moments with Mach number, and variation of section loads with Mach number are provided.

Note presenting an investigation to provide a means for calculating the heat required for the prevention of fog formations on the inside surfaces of single-panel bullet-resisting windshields during diving flight. An analysis was made to provide relationships for the heat required considering the transient heating of the windshield during diving flight.

"Steady, diabatic (nonadiabatic), frictional, variable-area flow of a compressible fluid is treated in differential form on the basis of the one-dimensional approximation. The basic equations are first stated in terms of pressure, temperature, density, and velocity of the fluid. Considerable simplification and unification of the equations are then achieved by choosing the square of the local Mach number as one of the variables to describe the flow" (p. 1).

Report presenting the performance of a set of axial-flow fan and compressor rotor blades with high design loading in a low-speed test blower. The efficiency curve, efficiency contours, comparison of pitch-section turning angles, and simulated blade roughness are provided.

Note presenting the results of tests to determine the combined effects of rigidity and thickness of wire strain gages on indicated bending strains in thin sheet metal for 15 types of single-element multistrand wire strain gages. In most cases, the indicated extreme-fiber bending strain was greater than the actual strain. The positive error caused by the finite thickness of the gage predominated over the negative error caused by the rigidity of the gage.

Report presenting an investigation at low speed of the downwash behind various small-scale sweptback wings. The wing configurations used in the testing ranged from aspect ratios of 2.5 to 4.0, sweepback angles from 32.5 degrees to 40 degrees, and ratios of root chord to tip chord of 0.62 to 2.06. Results regarding the effect of aspect ratio, effect of taper ratio, effect of tail span and position, and effect of high-lift devices are provided.

Report presenting testing of a gas turbine with rotor blades of a sillimanite-base ceramic material that was designed, constructed, and operated to determine the practicability of ceramics for gas-turbine blading. Two different types of blades were used. Testing indicated that ceramic-blade turbines can be operated at high inlet gas temperatures and moderate speeds for short life, but modifications for extending their life may be possible.

Report presenting some charts on the reflection of a propeller on the basis of efficiency for application to a light airplane design. Various values of power are covered for several different airspeeds, propeller diameters, and blade numbers.

Report presenting calculations of the rotational-noise and vortex-noise loudness levels at distances of 300 and 1000 feet for a variety of propellers with different blade numbers, diameters, and rotational speeds. Calculated results are presented in a chart for designers of propellers.

"A concise nonmathematical review of the subject of boundary layers is presented. The contents, although insufficient for the solution of specific problems, are sufficient for an introduction to the subject. A list of reference papers is given from which the detailed knowledge necessary for the solution of specific problems can be obtained" (p. 1).

Note presenting a continuation of a theoretical investigation of the stability of the laminar boundary layer in a compressible fluid. A series of equations are given that provide information related to Reynolds number effects and the physical significance of the stability analysis.

Note presenting a method for strength analysis of stiffened shear webs, which has been revised and extended from a previous report. A set of formulas and graphs which cover all aspects of strength analysis is given, experimental data are presented, and the accuracy of the formulas as judged by comparison with the data is discussed.

Report presenting tests to determine the effect of heat on the pressure drop through radiator tubes made to establish the adequacy of previously developed theory. Results regarding the evaluation of incompressible pressure drop, tubes with smooth entrances, and tubes with transition fixed are provided.

Report presenting theoretical and experimental data for NACA 6A-series basic thickness airfoils, which were designed to eliminate the trailing-edge cusp present in NACA 6-series sections. Results indicated that the section minimum-drag and maximum-lift characteristics of the 6-series and 6A-series airfoil sections are essentially the same. Drag, lift, pitching-moment characteristics, and aerodynamic center are also provided.

Note presenting an analytical method for calculating the hydrodynamic impact loads and motions experienced by seaplane floats and hulls with scalloped (fluted) bottoms. The analysis, which is applicable to floats with cross sections of any shape, considers that the flow about an immersing planing bottom occurs largely in transverse flow planes which are normal to the keel.

Note presenting the results of force tests and pressure-distribution measurements from a wind-tunnel investigation to determine the effects of size and hinge location of lift and trim flaps on the lift and pitching moment characteristics of a semispan tapered wing with 23 degrees sweepback of the quarter-chord line. The flaps were tested with different chords, spans, and trim flaps. The results indicated that the static longitudinal stability of the sweptback wing, as indicated by the slope of the curves of pitching-moment coefficient against lift coefficient, was increased when the lift flaps were deflected, especially for the larger flaps.

Note presenting an investigation conducted to determine the effect of power and of full-span slotted flaps on the static lateral stability and control characteristics of a single-engine high-wing airplane with tail on and tail off. The model combinations investigated included three power conditions, including with the propeller off, propeller windmilling, and power on, and tested with the flap neutral, single slotted flap, and double slotted flap.

Note presenting an investigation conducted to determine the effect of power and full-span slotted flaps on the longitudinal stability and control characteristics of a single-engine high-wing airplane. The model was tested at three power conditions: propeller off, propeller windmilling, and power on, and with the flap neutral, single slotted flap, and double slotted flap. The results indicated that deflection of the double slotted flap produced almost twice as much lift increment as did the deflection of the single slotted flap.

Report presenting an investigation in the two-dimensional low-turbulence tunnel to find the effects of boundary-layer control on the aerodynamic characteristics of the NACA 65(sub 4)-421 airfoil section with a boundary-layer-control suction slot at 0.45 airfoil chord and a 0.32-airfoil-chord double slotted flap. The airfoil is designed primarily to obtain a high maximum lift coefficient. Results regarding lift and drag characteristics are provided.

Report presenting a wind-tunnel investigation to determine the aerodynamic characteristics of a horizontal tail surface with various amounts of unshielded horn balance and with the surface condition similar to that of a typical fabric-covered elevator.