Report presenting an analysis showing the effect of several design variables on turbine-wheel flight. Equations are developed for the calculations of weights of the disk, the rim, and the blades, and use the following variables: the blading aspect ratio and solidity, the ratio of the centrifugal stress at the blade roots to that in the disk, and the ratio of wheel diameter at the blade root to wheel diameter at the blade tip.

Report presenting a solution for the problem of the compressive buckling of simply supported, flat, rectangular, Metalite type sandwich plates stressed either in the elastic or plastic range. Charts for the analysis of long sandwich plates are provided for plates with face materials of 24S-T3 aluminum alloy, 75S-T6 Alclad aluminum alloy, and stainless steel.

"Results are presented of calculations for the elastic buckling load of a simply supported flat rectangular plate of uniform thickness subjected to unequal compressive stresses at two opposite edges, with a linear variation of stress between the two edges. The difference between the compressive stresses at the two loaded edges is equilibrated by shear stresses along the other two edges. The results show that a plate with a linear stress gradient will buckle at an average stress that is lower, but at a maximum stress that may be appreciably higher, than the uniform compressive buckling stress of the same plate" (p. 1).

Note presenting the compressive buckling stress of outstanding flanges reinforced by bulbs, which was computed by the strain-energy method for flanges with 10 shapes and a range of lengths. The results were checked for some cases by computations based on a differential-equation method. The results were analyzed to determine which shape of flange gave the greatest support to the structure to which it was attached.

Note presenting a low-turbulence wind tunnel investigation of an NACA 64A010 airfoil with a porous surface of sintered bronze to determine the reduction in section drag coefficient that might be obtained at large Reynolds numbers by use of suction to produce continuous inflow through the surface of the model. Results regarding the uncompartmented model, compartmented model, observations on stability of laminar boundary layer, and theoretical calculations are provided.

Report presenting an investigation of the flutter of a small one-blade wooden propeller with a Clark Y section. The highest flutter speeds were found in the vicinity of the angle of zero aerodynamic moment, with flutter speed increasing in this region with decreasing pressure.

Note presenting experimental pressure-time measurements along with schileren photographs of the unsteady-flow phenomena initiated in constant-cross-sectional-area passages. The methods of calculation of the flow phenomena are based on the assumptions of one-dimensional, nonviscous, unsteady flow.

Note presenting an investigation of a two-blade and a three-blade propeller on a slender-nose fighter airplane in climb and at high speed.

Report presenting a method for the calculation of flutter speed of a uniform wing carrying an arbitrarily placed concentrated mass. The method involves the solution of the differential equations of motion of the wing at flutter speed and does not require the assumption of specific normal modes of vibration.

Report presenting the theory for calculating the free-space oscillating pressures associated with a rotating propeller at any point in space. Good agreement was found between analytical and experimental results using this method. Results regarding vibration and sound levels in the fuselage in relation to pressure level are reported.

Measurements have been made of the mean total-head and temperature fields in a round turbulent jet with various initial temperatures. The results show that the jet spreads more rapidly as its density becomes lower than that of the receiving medium, even when the difference is not sufficiently great to cause measurable deviations from the constant-density, dimensionless, dynamic-pressure profile function. Rough analytical considerations have given the same relative spread. The effective "turbulent Prandtl number" for a section of the fully developed jet was found to be equal to the true (laminar) Prandtl number within the accuracy of measurement. (author).

Report presenting tests in the gust tunnel of the 30 degree sweptback wing model to provide information on some of the problems encountered in the prediction of gust loads for airplanes incorporating swept wings. The results indicate that within the scope of the data and the values of gradient distance investigated, the maximum acceleration increment depends on the slope of the lift curve of an equivalent straight wing multiplied by the cosine of the angle of sweep and on the effect of gradual penetration of the sweptback wing into the gust.

Report presenting a wind-tunnel investigation at low Mach and Reynolds numbers to determine the high-lift and lateral control characteristics of a semispan wing of NACA 65(sub 2)-215 airfoil section equipped with a 25-percent-chord, full-span, slotted flap and plug and retractable ailerons. The ailerons were located at the 70-percent-chord station over the outer 49 percent of the wing semispan and were fabricated in five spanwise segments. Results regarding the wing aerodynamic characteristics, lateral control characteristics, comparison of lateral control characteristics of the plug and retractable ailerons, and a comparison of lateral control characteristics of the plug and retractable ailerons on the present wing with similar ailerons on an NACA 65-210 wing are provided.

Note presenting a prismatic-float forebody with an angle of dead rise of 40 degrees that was subjected to smooth-water impacts in the impact basin. The tests were made at fixed trims of 3, 6, 9, and 12 degrees for a range of flightpath angles from approximate 2 to 22 degrees. The data are presented and converted into dimensionless variables for correlation of the experimental results with hydrodynamic impact theory and for comparison of the runs among themselves.

Report presenting combined force and wake survey tests on three-blade model propellers in order to determine the effects of blade-width distribution on constant-speed efficiency characteristics. The most important result is the demonstration that blade-width distribution has a marked influence on the constant-speed efficiency characteristics of propellers.

Report presenting testing to determine the force developed in a shock strut as a function of the flexibility of the attached wing structure. Both the experiment and analysis indicated that wing flexibility had some effect on the shape and peak value of the force-time curve in a shock strut.

"In order to provide engineers interested in rotating-wing aircraft but with no specialized training in stability theory some understanding of the factors that influence the flying qualities of the helicopter, an explanation is made of both the static stability and the stick-fixed oscillation in hovering and forward flight in terms of fundamental physical qualities. Three significant stability factors - static stability with angle of attack, static stability with speed, and damping due to a pitching or rolling velocity - are explained in detail" (p. 1).

Report presenting a wind-tunnel investigation conducted in rolling flow to determine the effects of aspect ratio and sweep on the rolling stability derivatives for a series of untapered wings. The results indicated that when the aspect ratio is held constant, an increase in sweepback angle causes a significant reduction in the damping in roll at low lift coefficients for only the higher aspect ratios tested.

From Summary: "An investigation has been conducted in the NACA Cleveland icing research tunnel to determine the aerodynamic and icing characteristics of several recessed fuel-vent configurations. The vents were investigated aerodynamically to obtain vent-tube pressures and pressure distributions on the ramp surface as functions of tunnel-air velocity and angle of attack. Icing investigations were made to determine the vent-tube pressure losses for several icing conditions at tunnel-air velocities ranging from 220 to 440 feet per second. In general, under nonicing conditions, the configurations with diverging ramp walls maintained, vent-tube pressures greater than the required marginal value of 2 inches of water positive pressure differential between the fuel cell and the compartment containing the fuel cell for a range of angles of attack from 0 to 14deg at a tunnel-air velocity of approximately 240 feet per second."

Report presenting generalized radiation charts for the calculation of the irradiation from water vapor, carbon dioxide, ozone, and the earth in terms of appropriate parameters. Nocturnal irradiation was found to decrease greatly as a function of altitude and meteorological conditions.

Report presenting a comparison of the thermal performance and pressure-drop characteristics of heat exchangers on a heat-exchanger test stand. The exchangers included parallel and cross-flow units as well as extended-surface and all-prime-surface units.

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.

Note presenting an experimental investigation conducted to determine the orifice coefficient of a jet directed 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. Results regarding jets discharging into still air and effect of tunnel-air velocity on jet flow.

"The icing characteristics of two typical light-airplane engine induction systems were investigated using the carburetors and manifolds of engines in the horsepower ranges from 65 to 85 and 165 to 185. The smaller system consisted of a float-type carburetor with an unheated manifold and the larger system consisted of a single-barrel pressure-type carburetor with an oil-jacketed manifold. Carburetor-air temperature and humidity limits of visible and serious Icing were determined for various engine power conditions" (p. 1).