Fuel-Economy Possibilities of Otto-Cycle Aircraft Engines 390151
MR. HERSEY shows that excellent economy can be obtained from the Otto-cycle aircraft engine by operation at high compression ratios, high mechanical efficiency values, and optimum spark advance. The limiting factor affecting such desirable operation is found to be detonation which can be suppressed by several means that are generally different for the cruising and high-output power conditions.
The paper outlines the general and economy requirements of existing aircraft engines, and the economy effects of various operating conditions. The factors that affect detonation at both high output and economy conditions, as well as the compromises necessary to avoid detonation, are considered in some detail.