freewheel unit

freewheel unit

Normal operating position: The engine (outer) and rotor (inner) side of the cogs are in equal contact.

Over running position: The engine is turning slower than the rotor. The rotor is free-wheeling.

A device placed in a drivetrain to permit the rotor of a rotorcraft to continue to turn after an engine failure or to turn faster than the driving part of the engine.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved