• The output shaft of the engine is bolted directly to the lower sheave (pulley

• The lower sheave transmits power to the upper sheave through the vee belts

• The upper sheave has an overrunning clutch (sprag clutch) contained in its hub

• The inner shaft of the clutch transmits power forward to the main rotor gearbox, and aft to the tail rotor gearbox                                                                                                                                                                                                                             
• The tail rotor gearbox is geared to increase the RPMs to the tail rotor (Over Driven), and the main rotor gearbox is geared to decrease the RPMs to the main rotor (Under Driven)