Data are presented to show the effects of inlet-air pressure, inlet-air temperature, and compression ratio on the maximum permissible performance obtained with a cylinder having a hemispherical-dome combustion chamber. The five aircraft engine fuels used have octane number varying from 90 to 100 plus 2 ml of tetraethyl lead per gallon. The results for each fule can be correlated by plotting the calculated end-gas density factor against the calculated end-gas temperature. Measurements of spark-plug electrode temperatures showed thta, with two spark plugs, cutting off the switch to one spark plug lowered the electrode temperature of that plug from a value of 1,365 degrees F to a value of 957 degrees F. The results indicate that the surface temperatures of combustion-chamber areas which become new sources of ignitiion markedly increase after ignition commences.

Includes the Committee's Reports no. 1-1058, reprinted in v. 1-37.