Pistonless rotary engine

A pistonless rotary engine is an <a href="/facts/Internal_combustion_engine/Ju4BXzj0">internal combustion engine</a> that does not use <a href="/facts/Piston/z7pN46u7">pistons</a> in the way a <a href="/facts/Reciprocating_engine/ItLAxmW3">reciprocating engine</a> does. Designs vary widely but typically involve one or more rotors, sometimes called rotary pistons, as described in QT-Wankel: Two Concepts 100 Years Apart. Although many different designs have been constructed, only the <a href="/facts/Wankel_engine/IstzAyor">Wankel engine</a> has achieved widespread adoption.
The term rotary combustion engine has been used as a name for these engines to distinguish them from early (generally up to the early 1920s) <a href="/facts/Aircraft_engine/XJo2Bd2e">aircraft engines</a> and <a href="/facts/Motorcycle_engine/Xj1V5thg">motorcycle engines</a> also known as <a href="/facts/Rotary_engine/QkxnRk0x">rotary engines</a>. However, both continue to be called rotary engines and only the context determines which type is meant, whereas the "pistonless" prefix is less ambiguous.

Pistonless rotary engine open-in-new

Pistonless rotary engine