Report presenting a method of graphical analysis that allows for the prediction of the thermal and aerodynamic performance of a ram-operated heater and duct system, for cabin heating or wing de-icing, at any altitude and airplane speed. Performance can be predicted from the isothermal total pressure drop across the components of the duct system at several ventilating air rates and the thermal output of the heater at various air and exhaust gas rates.

Report presenting an investigation to determine any injurious effects of knock on engine parts. Endurance tests were run on a single-cylinder engine to compare the conditions of cylinders operated with and without knock. Results regarding the history of the tests, conditions of pistons and cylinders, absence of surface ignition, and effect of knock on cylinder temperatures are provided.

Report presenting a study to determine the effect on the knock-limited permissible power output on the indicated specific fuel consumption and on the cylinder temperatures of exhaust-gas dilution of the inlet-air charge, inlet-air temperature without exhaust-gas dilation, and of compressible ratio.

Report presenting a consideration of the performance of sliding surfaces, such as piston rings, cylinders, journals, and bearings in aircraft engines with reference to the surface characteristics that they possess before and after running-in, prior to service operation. The phenomena accompanying the running-in process are analyzed.

Report presenting an investigation of thirteen exhaust-gas-to-air heat exchangers to determine the practicability of the use of such heat exchangers in the thermal ice-prevention systems on aircraft. The results show that the exchangers constitute an excellent source of heated air for aircraft ice prevention and can be constructed to resist thermal and vibrational stresses.

Report presenting an exploration of the electrical effects that glider tows operating in or near a thunderstorm may experience. The three primary hazards are a direct lightning strike, a lightning strike that passes to some intermediate point on the towline, and an electrical current of appreciable magnitude flowing in the towline the whole time that the tow is within a few miles of the thunderstorm.