rotary engine
Contrary to popular belief, it was not "thought of by Felix Wankel when he was 17". It was developed in the late 1800's before his birth (in 1902).
Used mainly in aircraft, it essentially is a conventional piston-driven internal combustion engine, with the pistons set radially around the center crankshaft. The difference is that the whole engine block rotates around the crankshaft, rather than the pistons turning the crankshaft.
The pistonless rotary engine, as produced by Mazda, was initially designed by Felix Wankel as others describe, yes, but putting his name on all rotary engines is like saying that all watermelons are seedless.
Used mainly in aircraft, it essentially is a conventional piston-driven internal combustion engine, with the pistons set radially around the center crankshaft. The difference is that the whole engine block rotates around the crankshaft, rather than the pistons turning the crankshaft.
The pistonless rotary engine, as produced by Mazda, was initially designed by Felix Wankel as others describe, yes, but putting his name on all rotary engines is like saying that all watermelons are seedless.