Murray Rotary Engine

Type: Rotary, 6 cylinders, air-cooled, 2-stroke, supercharged

Power rating: 22.4 kW (30 hp) at 1,200 rpm

Displacement: 2.4 L (146 cu in.)

Bore and Stroke: 75 mm (2.95 in.) x 90 mm (3.54 in.)

Weight: 60 kg (132.3 lb)

The Murray engine is the earliest American supercharged engine still in existence. In 1911, Joseph J. Murray began design of air-cooled, valveless, 2-stroke, supercharged rotary engines, with the first model tested early in 1912. The engines were developed by the Murray-Willat Company, and built by the American Motors and Aviation Company, where Murray briefly served as Secretary-Treasurer. Murray engines were built through 1914.

This model followed the earlier 18.6 kW (25-hp) and 52 kW (70-hp) engines, and used an improved vane-type supercharger. Murray’s engines never flew, but this artifact was installed in a Murray-designed monoplane that served as a prop in two early movies produced at Mack Sennett’s Keystone Studios, Saved by Wireless and Civilization. The aircraft was heavily damaged during production of Civilization and apparently not used again. The artifact is mounted on its original metal test stand.