Almost every internal combustion vehicle on the planet today uses the classic piston engine. These run by converting heat energy into reciprocating motion, and then rotary motion that ultimately powers the wheels through the drivetrain. But what if you could produce a rotary motion directly from combustion? That was the dream of Dr. Felix Wankel, who, after working on the design for more than 30 years, created the world's first rotary engine in collaboration with German motorcycle and automobile manufacturer, NSU. The Wankel rotary was a very promising engine. The German Nazi regime saw it as a competitive advantage over...