Mcdonnell Douglas Helicopter Company

Thomas G Ashe

Robert E Head

Channing S Morse

An engine control system for a helicopter having at least one engine is provided, including an electronic engine control unit for each engine and further including a manually operated system for backing up each electronic engine control unit in the event of a failure thereof or for permitting optional manual engine operation. The engine control system includes at least one collective pitch stick and at least one twist grip rotatably mounted on the collective pitch stick. Each twist grip includes a normal (NORM) position within the range of the operating arc which is coincident with a detent. The system includes means for electronically actuating the detent to retract when the twist grip is rotated out of the NORM position into a manual operating mode, so that the electronic disablement of the detent permits an operator to smoothly operate the twist grip through the operating arc when the engine control system is in a manual control mode. The twist grip further includes an additional arc of travel past the idle stop to an OFF position, wherein fuel flow to its corresponding engine is cut off. Significantly, the system includes an electrically actuated mechanical gate over which the twist grip must pass to enter or exit the OFF position. The gate is normally biased closed, and may be opened electrically by means of a pilot-actuated off release pushbutton to enter the OFF position, or may be opened mechanically by twisting the twist grip against the bias to exit the OFF position.

Growing community of inventors

Apache Junction, AZ, United States of America

Thomas G Ashe