Ray Williams of New York built both a 1/3 scale model of the Gnome 160 horsepower rotary engine and the World War I Avro 504K airplane that was designed in 1913 in the United Kingdom. Williams flew his model in December 2001, making this the first model rotary engine ever to fly.
The model engine, as in the full-size engine, operates on gasoline with spark ignition and a pressurized oil system. It has a displacement of 27 cu. in. and the engine itself weighs 11 pounds. The engine is 24″-long, 16″-wide, and 19″-high. The scale model Avro 504K that the engine was fitted into had a 12-foot wingspan.
The first successful air-cooled rotary engine was developed in 1896 in the United States. The French-built Gnome rotary was used extensively in airplanes during World War I. A typical rotary engine has a fixed crankshaft with rotating cylinders and crankcase that carry the propeller. Since the oil cannot be reclaimed from a rotating engine, it is discharged after combustion. (This is known as a “total loss” oiling system.) WWI pilots would constantly have to wipe off their goggles and windscreens from this oil spray during flight.