The rotary engine was an unconventional design that delivered great power for its size. Here's what's good and bad about it.

Astron aerospace has shown a partial prototype of a new rotary combustion engine it claims runs at an extraordinary 60% thermal efficiency, burning totally clean with zero NOx emissions and nothing ...

Rotary engines (also known as Wankel engines and Wankel rotary engines) are quite different from piston or "reciprocating" engines. One of the distinguishing features is that they don't need valves to ...

For a time, the Wankel rotary engine seemed like the future. In 1963, German automaker NSU—later absorbed into Audi—debuted the Wankel Spider, the first internal-combustion production car not powered ...

In theory, Wankel-style rotary internal combustion engines have many advantages: they ditch the cumbersome crankcase and piston design, replacing it with a simple, single-chamber design and a thick, ...