Plain English Meaning

A jet-style engine that, instead of pushing the aircraft along with exhaust, uses its turbines to spin a shaft. That shaft then turns something useful — most often a helicopter rotor.

Full Definition

A turbine engine in which most of the power produced by the expanding gases is used to drive a shaft rather than to produce thrust through the exhaust. The shaft typically drives a rotor system in a helicopter, a propeller through a reduction gearbox, or another mechanical load such as an auxiliary power unit.

Context Anchor

Seen in turbine engine discussions, especially when comparing helicopter engines with turbojet, turbofan, and .