DEMONSTRATING the versatility of the hemi-U spherical or spherical segment combustion chamber, a series of carefully controlled tests has been completed in connection with experimental engine developments, as described by the author of this paper. Using regularly available fuels, or stimulated with super fuels, the engines showed power outputs far greater than the previous designs.
The author points out that identical test engines, differing only in combustion-chamber design and valve layouts, showed that a hemispherical head design had a thermal efficiency equal to one full compression ratio better than the next best design, the conventional overhead valve type.
The new engine, which develops more than 180 actual horsepower in the production version, using only nonpremium grades of fuel, is expected to respond to whatever demands may be made upon it when the anticipated quality fuels of the future become available.