Current helicopters use cam locking (friction type) over-running clutches to achieve a free wheeling behavior which is necessary in their drive trains. These conventional over-running clutches tend to be rather large and heavy when designed to meet functional and flight safety requirements. Epilogics has developed a unique positive locking over-running clutch called the Mechanical Diode (tm) (MD) which allows strong, lightweight and extremely reliable designs with almost complete immunity to torsional vibration. One version of the over-running clutch is presently manufactured by Epilogics for automotive racing applications where strength and durability are critically important. We propose to design, build and test a version of the over-running clutch suitable for helicopter use by determining the correct internal geometric shapes for extremely high speed over-running, up to 30,000 rpm. We expect to achieve a design which will be suitable for use between a helicopter engine and drive train. This over-running clutch will provide helicopter driveline manufacturers a lighter, stronger (per unit weight), more reliable and torsionally rigid alternative to the sprag and roller ramp devices presently in use.
