Editing Pistonless rotary engine (section)

{{short description|Internal combustion engine}}
{{About|pistonless design|other uses of this term|rotary engine (disambiguation)|the early piston design|rotary engine}}
{{more citations needed|date=April 2016}}
[[File:Rotary Engine Photo Sequence 01.gif|thumb|[[Libralato engine]] ]]

A '''pistonless rotary engine''' is an [[internal combustion engine]] that does not use [[piston]]s in the way a [[reciprocating engine]] does. Designs vary widely but typically involve one or more [[wikt:rotor|rotor]]s, sometimes called '''rotary pistons''', as described in QT-Wankel: Two Concepts 100 Years Apart.<ref>{{cite journal |author=Gilles Saint-Hilaire |author2=Roxan Saint-Hilaire |author3=Ylian Saint-Hilaire |author4=Françoise Saint-Hilaire |journal=International Journal of Science and Research |volume=14 |issue=2 |date=February 2025 |url=https://www.ijsr.net/archive/v14i2/SR25210033851.pdf |title=Comparative Analysis of Quasiturbine and Wankel Rotary Engine: Two Concepts 100 Years Apart |pages=723–743 |doi=10.21275/SR25210033851}}</ref> Although many different designs have been constructed, only the [[Wankel engine]] has achieved widespread adoption.

The term '''rotary combustion engine''' has been used as a name for these engines{{Citation needed|date=July 2010}} to distinguish them from early (generally up to the early 1920s) [[aircraft engine]]s and [[motorcycle engine]]s also known as ''[[rotary engine]]s''. However, both continue to be called ''rotary engines'' and only the context determines which type is meant, whereas the "pistonless" prefix is less ambiguous.