COMPARISON OF COMPUTED PERFORMANCE OF COMPOSITE POWER PLANTS USING 18-CYLINDER AIRCRAFT ENGINES WITH 62° AND 40° VALVE OVERLAP

摘要

Calculations based on experimental data for 18-cylinder, radial aircraft engines with different nominal valve overlaps (62° and 40°) were made to compare the performance of two composite power plants using these engines. The composite unit included, in addition to the engine, a steady-flow turbine and an auxiliary supercharger mounted on a common shaft and geared to the engine crankshaft.nThe calculations indicated that, in general, the system U6ing the engine with 40° valve overlap was slightly more efficient and provided more power at the optimum operating conditions than the system incorporating the engine with the 62 valve overlap when fuel was introduced by means of a carburetor.