The World's Weirdest Rotary Engine Is A 118-Year-Old French Spinner That Leaks Castor Oil Everywhere

Wankel rotary engine powered thousands of aircraft. One of several problems: It spewed castor oil on its pilots.
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Gnome Monosoupape Type N Rotary 9 Engine

Displacement: 15.9 L (970.38 cu in.) Bore and Stroke: 115 mm (4.53 in.) x 170 mm (6.69 in.) The rotary engine reduced rough the running and overheating of early air-cooled engines, namely.