Plain English Meaning

An aircraft that looks a bit like a small helicopter, but the overhead rotor is not driven by the engine. The engine drives a propeller that pushes or pulls the aircraft forward, and the moving air spins the rotor on its own to create lift.

Full Definition

A rotorcraft whose lift is produced by a rotor that is not powered by the engine but is turned by air flowing up through it as the aircraft moves forward (autorotation). Forward thrust is provided by a separate engine-driven propeller. The rotor spins freely at all times in flight.

Context Anchor

Seen in light-sport aircraft material as one of the aircraft types a sport pilot may operate with the proper training and privileges.