Memorandum presenting a preliminary investigation to determine the effects of alpha-particle bombardment on the creep rate of aluminum wire at 400 degrees Fahrenheit. The alpha radiation from an 85-millicurie polonium source appeared to decrease slightly the creep rate of the aluminum.

"A method is described by which the total temperature of the gases at the combustion-chamber outlet of a ram-jet engine may be determined from the loss in total pressure measured across the combustion chamber. A working chart is presented by means of which the ratio of the total temperature of the gases at the combustion-chamber outlet to the total temperature of the gases at the combustion-chamber inlet may be determined from the measured loss of total pressure across the combustion chamber and the known values of air flow, total pressure, and total temperature at the combustion-chamber inlet. Values of total-temperature ratio across the combustion chamber of a 20-inch ram jet were obtained in the Cleveland altitude wind tunnel over a range of pressure altitudes from 6000 to 15,000 feet" (p. 1).

Report presenting a correlation of carbon deposition of 19 fuels in a turbojet combustor as a function of the boiling point and of the flame height at the sooting point of the fuels in a simple wick lamp for a particular combustor operating at a single set of conditions. Two similar investigations with different combustors, operating conditions, and nine different fuels yielded similar correlations on the same graph.

Report presenting an experimental investigation to determine the vibration characteristics of loosely mounted turbine blades during service operation of a turbojet engine. High-temperature strain gages were used to measure turbine-blade vibrations. Results regarding oscillograph records, critical speeds and frequencies, vibratory-stress levels, and effect of tightening the blade mount are provided.

Report presenting the effects of fuel properties and change in simulated engine operating conditions on carbon deposition in an annular turbojet combustor. The fuel properties examined included specific gravity, volumetric average boiling temperature, hydrocarbon type, and hydrogen-carbon weight ratio. The fuels included hydrocarbons of the paraffinic, olefinic, and aromatic types as well as fuel mixtures.

Report presenting a wind-tunnel investigation to determine the effects of leading-edge radius and maximum thickness-chord ratio on the variation with Mach number of the aerodynamic characteristics of several thin symmetrical NACA 4-digit-series airfoil sections. The variations with Mach number of the lift, drag, and pitching moment for a 4-percent-chord-thick airfoil section are not significantly affected by a change of leading-edge radius from 0.18 to 0.53 percent of the chord. Results regarding the leading-edge radius effects and maximum thickness-chord ratio are provided.

Work was completed on the high-temperature, high efficiency air filter. Technical assistance was given at a large-scale, privately financed run of an all-glass medium. Full-size filers have been produced in quantity and are offered by manufacturers; it is considered that commercial manufacture has been established. A survey was made of air sampling practices at 37 laboratories. Analysis of the survey results indicated that 22 different kinds of air-sampling filer media were in use among the laboratories questioned. We have recommended that air-assay practice be simplified by use of fewer media. A group of five media has been proposed as adequate for meeting all requirements. Laboratory work was done on the development of a high-efficiency, low-ash, all-purpose, air-assay paper. Two methods of approach were tried. In one an effort was made to produce cellulose fibrils in sufficient quantity and quality to act as the fine-fiber component of a filter. Only moderate success was attained. Better promise was shown by combining synthetic organic microfibers with cellulose fibers in a wet-formed sheet. No plant work was undertaken on this item.

Memorandum presenting the results of an investigation to establish rupture and total-deformation strengths at 1200 and 1800 degrees Fahrenheit for typical commercial treatments of low-carbon N-155 alloy. The results show that there were large differences in strength between the heats of bar stock at temperatures above 1200 degrees Fahrenheit except when a 2200 degree Fahrenheit solution treatment was used.