Engine builder known as "Cleveland Aero Motor Co." OH.

-Walter Willard builds the "4" model engine in 1917. An air-cooled, 6-cylinder radial with 707 cu. in. of displacement giving 140/150 hp.

-It is a "barrel" type engine, but unlike what has been seen so far. It does not have an inclined plate but a series of planetary gears driven by individual crankshafts for each cylinder.

“Cleveland”

-As it has the planetary system of the same size, the reduction is done exactly in the middle. It has four valves per cylinder, two intake valves and two exhaust valves.

-They planned a range from 100 hp to 600 hp. The shown diagram belongs to model 4 that gave 150 hp.