Performance of a 300-horsepower Hispano-Suiza airplane engine

The National Bureau of Standards tested a 300-horsepower Hispano-Suiza engine to determine the characteristic performance of the engine at various altitudes. The engine was operated at the ground, at 25,000 feet, and at intermediate altitudes, both at full loads similar to those that would be imposed upon the engine at various speeds by a propeller whose normal full-load speed was 1,800 r.p.m. Friction horsepower also was determined in order that the mechanical efficiency of the engine might be calculated. From the test data there were computed the brake horsepower, brake mean effective pressure, specific fuel consumption, mixture ratio, jacket loss, exhaust loss, and thermal, mechanical, and volumetric efficiencies. A record of jacket water temperatures, oil temperatures, manifold pressures, etc., shows the conditions under which the test was made.