What did Felix Wankel of Germany develop in 1954?

Felix Wankel of Germany developed the rotary engine in 1954, the design that became known as the Wankel engine. It uses an eccentric, roughly triangular rotor instead of the pistons found in conventional reciprocating engines.

Wankel began working with NSU Motorenwerke in Germany in the early 1950s. In 1954, NSU agreed to develop a rotary internal-combustion engine based on his work. The first running prototype appeared in 1957, and NSU later introduced the Wankel Spider, the first production car powered by a rotary engine, in 1964.

The design became especially associated with Mazda, which developed rotary-powered cars including the RX-7 and RX-8. Rotary engines are compact, light, smooth-running and made from relatively few moving parts. However, sealing challenges, fuel consumption and emissions limited their widespread adoption. Wankel engines are sometimes simply called rotary engines, although the broader term can also describe other kinds of rotary combustion engines.