"The trajectories of droplets in the air flowing past NACA 65(1)-208 airfoil and an NACA 65(1)-212 airfoil, both at an angle of attack of 4 degrees, were determined. The amount of water in droplet form impinging on the airfoils, the area of droplet impingement, and the rate of droplet impingement per unit area on the airfoil surface affected were calculated from the trajectories and are presented. The amount, extent, and rate of impingement of the NACA 65(1)-208 airfoil are compared with the results for the NACA 65(1)1-212 airfoil" (p. 1).

An analytical investigation of incompressible flow about wedges was made to determine effects of tunnel-wedge ratio and wedge angle on the wedge pressure distributions. The region of applicability of infinite wedge-type velocity distribution was examined for finite wedges. Theoretical and experimental pressure coefficients for various tunnel-wedge ratios, wedge angles, and subsonic Mach numbers were compared.

Note presenting fatigue data for 76S-T61 aluminum alloy for several combinations of bending and torsion with both alternating and mean stresses. The literature on the effect of combined stress and of mean stress in fatigue is reviewed and the results of the present series are compared with those of various theories. Results regarding fatigue data, fatigue fractures, and static tests are provided.

Report presenting static force-deflection tests on six aircraft tires ranging in size and ply rating. Testing included the vertical loading of all six tire specimens and, for five of the tire specimens, combined vertical loading and side loading and combined vertical loading and torsional loading.

The creep of single crystals of high-purity aluminum was investigated in the range of temperatures from room temperature to 400 F and at resolved-shear-stress levels of 200, 300, and 400 psi. The tests were designed in an attempt to produce data regarding the relation between the rate of strain and the mechanism of deformation. The creep data are analyzed in terms of shear strain rate and the results are discussed with regard to existing creep theories.

"The results of an experimental investigation of the strength of plane diagonal-tension webs with ratios of web depth to web thickness of about 60 are presented. An analysis of the beam indicated that the methods of strength analysis presented in NACA TN 2661 are applicable to beams with flanges symmetrically arranged with respect to the web if the portal-frame effect is taken into account" (p. 1).

Report discussing a new high-speed photographic technique, which employs a variable-frequency light synchronized with a commercially available 16-millimeter high-speed motion-picture camera without appreciable alterations to the camera. The technique is described and results obtained by the technique of photographing the flow past models in a wind tunnel with the schileren method of flow visualization are presented.

Report presenting a new shadowgraph technique for the observation of conical flow phenomena in supersonic flow. The particular advantage of this technique is that it permits observation of the conical flow phenomena in a plane normal or nearly normal to the axis of propagation. Results regarding cones and triangular wings are provided.

Note presenting pressure distributions measured on a model helicopter rotor blade under hovering and simulated forward-flight conditions. Pressure were recorded at advance ratios of 0.10, 0.22, 0.30, 0.40, and 0.50 for a zero-offset flapping-hinge rotor and at 0.10, 0.22, 0.30, 0.45, 0.60, 0.80, and 1.0 for a lifting rotor with a flapping-hinge offset of 13 percent.

Report presenting testing of a flat-bottom V-step model with a beam loading of 4.6 subjected to fixed-trim impacts in smooth water. Testing occurred at three different trim angles and a range of initial flight-path angles. Data were obtained as time histories of draft, vertical velocity, and vertical acceleration. The results are presented as plots of nondimensional lift, draft, vertical velocity, and time against flight-path angle at contact.

"High operating temperatures of new and projected turbine engines require that synthetic fluids be used as lubricants, because these fluids have better thermal stability and viscosity-temperature characteristics than petroleum oils have. An experimental study was conducted to learn the effect of high lubricant bulk temperatures on the boundary lubricating effectiveness of various types of synthetic fluid" (p. 1).

Note presenting experimentally determined influence coefficients for the deflection of two solid delta wings - one wing of constant thickness and the other of constant thickness ratio - with a carry-through-bay chord smaller than the wing root chord. The experimental tip-load deflections of the constant-thickness wing exceed those computed by the present theory by approximately 15 to 20 percent at the tip.

Attenuation characteristics of four different resonator mufflers were determined in both cold tests and engine field tests and compared with the theoretical calculations. These mufflers were specifically designed for a helicopter. Engine-exhaust sound pressures, temperatures, and noise levels from the helicopter were measured. The experimental muffler cold tests indicated close a agreement with theory, whereas the engine tests indicated some discrepancies. Test results show the usefulness of the theoretical equation used for predicting muffler attenuation characteristics.

Report presenting results of experimental measurements of low-frequency combustion instability of a 300-pound-thrust acid-heptane rocket engine as compared with the trends predicted by an analysis of combustion instability in a rocket engine. Results regarding the chugging frequency, combustion time delay, effect of rocket combustion-chamber characteristic length, effect of throttling, effect of injection velocity, effect of oxidant-fuel ratio, variation of chugging frequency with amplitude of chamber pressure fluctuations, and evaluation of the analysis are provided.

Note presenting flight tests made with a typical light airplane to investigate possibilities for obtaining reliable control at low flight speeds. An attempt was made to find a configuration that would provide sufficient elevator control for a three-point landing under the most critical condition and that would also have insufficient elevator control to exceed the angle of attack at which reliable lateral control is obtained in flight under all of the center-of-gravity and power conditions.