Wankel rotary engine powered thousands of aircraft. One of several problems: It spewed castor oil on its pilots.

Here's the process of making this rotary valve engine with a different intake and an exhaust system. It wasn't easy to start ...

Join me as I tackle the challenges of repairing and rebuilding my custom rotary valve engine after a dramatic failed start and heavy smoke. Watch the detailed disassembly, from removing the covers to ...

The internal combustion engine, for all its mechanical sophistication, still runs on a 19th-century mechanical idea: pistons ...

A German engineer, Felix Wankel, is credited with developing the world's first rotary engine in the 1950s. Wankel rotary engines use a triangular rotor spinning in a semi-oval case on an eccentric ...

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 ...

In a world dominated by pistons, the rotary engine was something different for motorists. It was the vision of German engineer Felix Wankel, built on the belief that the up-and-down motion of pistons ...

While modern engines feature many tweaks and improvements on the original ideas, they usually aren't as interesting as the strange contraptions engineers experimented with in the early days. Take, for ...