ENGINE CONTROLS
The engine is operated using four separate controls consisting of an
emergency power lever, power lever, propeller control lever and a fuel
condition lever. The power and fuel condition levers are engine controls and
the propeller control lever controls propeller speed and feathering.
Power Lever
The power lever is connected, through linkages, to a cam assembly mounted
on the fuel control unit at the rear of the engine. The power lever controls
engine power through its full range from maximum takeoff to full reverse.
The power lever also controls the pitch of the propeller when placed in
BETA range. The power lever has MAX, IDLE, BETA and REVERSE range
positions. The range from the MAX position through IDLE allows selection
of the desired engine power output. The BETA range enables control of
propeller blade angle from idle thrust, through a zero thrust condition to
maximum reverse thrust.
Propeller Control Lever
The propeller control lever is connected, through linkages, to the propeller
governor mounted on top of the propeller reduction gearbox. The propeller
control lever controls the governor settings from the maximum RPM position
to full feather. The lever has two main positions: MAX and FEATHER. The
MAX position is used when a high RPM is desired and governs the propeller
speed at 2200 RPM. The FEATHER position is used during normal shutdown
of the engine to assist in stopping the rotation of the power turbine and front
section of the engine. Rotation of the forward section of the engine is not
desirable when the engine is shutdown, since lubrication is not available after
the gas generator section of the engine comes to a stop. With the propeller
feathered when the engine is shut down, propeller windmilling in gusty wind
conditions can also be minimized. A mechanical stop built into the pedestal
slot of the propeller control lever makes it necessary to move the propeller
lever to the left prior to moving the lever into or out of FEATHER.
Fuel Condition Lever
The fuel condition lever in the cockpit is connected through airframe linkage
to a combined lever and stop mechanism at the top of the fuel control unit
(FCU); this is connected by the FCU linkage to the cut-off lever on the side of
the unit. The lever and stop also function as a hi-idle stop. The fuel condition
lever performs the function of CUTOFF, LOW-IDLE and FLIGHT-IDLE. The
CUTOFF position shuts off all fuel to the engine fuel nozzles. LOW-IDLE
positions the control rod stop to provide a gas generator RPM of 52%
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