A theoretical and experimental investigation has been made of the behavior of a cantilever beam in transverse motion when its root is suddenly brought to rest. Equations are given for determining the stresses, the deflections, and the accelerations that arise in the beam as a result of the impact. The theoretical equations, which have been confirmed experimentally, reveal that, at a given percentage of the distance from root to tip, the bending stresses for a particular mode are independent of the length of the beam, whereas the shear stresses vary inversely with the length.

"Four airfoils sections, designed by the Republic Aviation Corporation for the root and tip sections of the XF-12 airplane, were tested in the Langley two-dimensional low-turbulence tunnels to obtain their aerodynamic characteristics. Lift characteristics were obtained at Reynolds numbers of 3,000,000, 6,000,000, 9,000,000, and 14,000,000, whereas drag characteristics were obtained at Reynolds numbers of 3,000,000, 6,000,000, and 9,000,000. Pressure distributions were obtained for one of the root sections for several angles of attack at a Reynolds number of 2,600,000" (p. 1).

"A continuous 50-hour test was conducted to determine the effect of maximum cruise-power operation at ultra-lean fuel-air mixture and increased spark advance on the mechanical conditions of cylinder components. The test was conducted on a nine-cylinder air-cooled radial engine at the following conditions:brake horsepower, 750; engine speed, 1900 rpm; brake mean effective pressure, 172 pounds per square inch; fuel-air ratio, 0.052; spark advance, 30 deg B.T.C.; and maximum rear-spark-plug-bushing temperature, 400 F. In addition to the data on corrosion and wear, data are presented and briefly discussed on the effect of engine operation at the conditions of this test on economy, knock, preignition, and mixture distribution" (p. 1).

Memorandum describing wind-tunnel tests made to determine the aerodynamic characteristics of a 20-percent-chord plain aileron on a semispan wing with the NACA 0012-64 section. The report includes the results of tests of the wing unswept and swept back 45 degrees and with the aileron deflected from 0 to 10 degrees.

Wind-tunnel tests of the McDonnell XP-85 airplane were conducted to determine its longitudinal, lateral, and directional stability and the characteristics of the aileron, the ruddervator, the leading-edge droop nose flap, and the stall control vanes. The directional stability of the airplane with numerous skyhook modifications and with a ventral fin was also investigated. The results of the tests showed that the effectiveness of the droop nose flaps and the stall control vanes was negligible with regard to either the maximum lift or longitudinal stability of the airplane. Contrary to any previous small-scale results, extension of the skyhook caused a 75-percent reduction in the directional stability of the airplane for both low and high values of lift coefficient. The simplest solution to the problem short of a major redesign of the skyhook appears to be the adoption of a ventral fin.

Report presenting the methods used to estimate and reduce the stresses in a swept propeller to be tested in the 8-foot high-speed tunnel. Specific information regarding the method for determination of stresses, method for reduction of moments, and relative magnitude of factors is provided.

From Summary: "An investigation has been conducted with the Langley helicopter tower to obtain basic performance and control characteristics of the Raman rotor system. Blade-pitch control is obtained in this configuration by utilizing an auxiliary flap to twist the blades. Rotor thrust and power required were measured for the hovering condition and over a range of wind velocities from 0 to 30 miles per hour. The control characteristics and the transient response of the rotor to various control movements were also measured."

Report presenting the results of a wind-tunnel investigation of the low-speed aerodynamic characteristics of a 45 degree sweptback horizontal-tail model of aspect ratio 2 and a comparison of these results with results for a model of the same aspect ratio with an unswept hinge line. Results regarding the lift and hinge-moment parameters, static longitudinal stability, effect of Reynolds number, effect of standard roughness, effect of removing elevator nose seal, and visualization of the air flow are provided.

A heat-transfer investigation was conducted with water flowing in an electrically heated Inconel tube with an inside diameter of 0.204 inch and a length-diameter ratio of 50 for ranges of Reynolds number up to 100,000 and of entrance pressure up to 200 inches of mercury gage. Correlation of average heat-transfer coefficients was obtained by use of the familiar Nusselt relation, wherein the physical properties of water were evaluated at an average bulk temperature. For conditions in which no boiling occurred, the data gave a good correlation. Runs made in the nucleate-boiling region, however, gave higher values of heat-transfer coefficient than would be predicted by the Nusselt relation.

Results of experimental measurements of low-frequency combustion instability of a 300-pound thrust acid-heptane rocket engine were compared to the trends predicted by an analysis of combustion instability in a rocket engine with a pressurized-gas propellant pumping system. The simplified analysis, which assumes a monopropellant model, was based on the concept of a combustion the delay occurring from the moment of propellant injection to the moment of propellant combustion. This combustion time delay was experimentally measured; the experimental values were of approximately half the magnitude predicted by the analysis.

The two techniques for conducting annealing experiments for the purpose of determining the distribution of atoms of a solid among non equilibrium states are considered. Related definitions for resolving power for annealing with steadily rising temperature and for annealing at a series of fixed temperatures are given. The necessary separation of activation energies for the resolution of two different non equilibrium states is found to be greater in the case of a steadily rising temperature, but of the order of 10 percent of the activation energy for both techniques. The resolving power in the case of a steadily rising temperature is independent of the rate of temperature rise.

Memorandum presenting a series of tests made on a full-scale Northrop XB-62 missile to determine the cause of a directional out-of-trim condition which was encountered on the initial missile flight tests. The results indicated that the directional out-of-trim condition was caused by aerodynamic loads induced by engine operation.

Report presenting the effects of inlet-air-flow distortion on the steady-state performance of a current axial-flow turbojet engine studied in an NACA altitude test chamber at a range of altitudes and simulated Mach number of 0.8. Radial distortions of various shapes up to 22 percent of the average engine-inlet total pressure and circumferential distortions up to 26 percent were imposed. Results regarding propagation through the engine, compressor-interstage performance and stall, effects on component performance, effects on overall engine performance, and effect on compressor blade vibration are provided.

The ideal temperature rise due to the constant-pressure combustion of a methylene (CH sub 2) fuel was calculated. CH sub 2 fuel closely approximates MIL-F-5624 grade JP-4 fuel presently used in most turbojet and ram-jet engines. Charts are presented from which the ideal temperature rise or the ideal quantity of fuel required to obtain a specified combustion temperature may be obtained for any flight condition likely to be encountered with turbojet or ram-jet engines using this fuel. The charts are applicable only to a fuel having a hydrogen-carbon mass ratio of 0.168.

Report presenting an investigation to determine the reverse-thrust performance of hemispherical target-type thrust reversers over a wide range of geometric variables. Several factors were found that increased the flow turn angle and reverse-thrust ratio, primarily the hemisphere diameter. Results regarding operating characteristics, relation of flow turn angle and reverse-thrust ratio, reverse-flow velocities and pressures along boattail, effect of boattail shape on reverse-thrust ratio, and modifications to hemispherical thrust reverser are provided.

Pressure-recovery characteristics of a nacelle-type-spike inlet in combination with a vertical-wedge auxiliary scoop are presented for a free-stream Mach number of 1.9 at zero angle of attack. The auxiliary scoop provided 17 percent additional air flow with a drop in critical pressure recovery from 0.86 to 0.81. However, in terms of inlet-engine matching, the pressure recovery of the undersized spike inlet operating at a specified corrected air flow increased with the scoop open, for example, from 0.69 to 0.81.