Governor/Correlator Functions in Helicopter Flight Control

Helicopter Flight Control: Functions of Governor/Correlator in Helicopter

Governor/Correlator in Helicopter Flight Control


A governor is a sensing device that detects rotor and engine rpm and makes required changes to maintain consistent rotor rpm. When the rotor rpm is set in normal operation, the governor keeps the rpm constant, thus no throttle adjustments are required. Governors are found on all turbine helicopters (as part of the turbine engine's fuel control system) and on certain piston-powered helicopters. 


A correlator connects the collective lever and the engine throttle mechanically. When the collective lever is raised, power is increased automatically, and when it is reduced, power is reduced automatically. This technique keeps rpms near to the desired level, but fine tuning involves adjusting the throttle. Because certain helicopters lack correlators or governors, all collective and throttle actions must be coordinated. The throttle must be increased when the collective is lifted, and it must be decreased when the collective is down. Large adjustments of collective pitch or throttle, like any other helicopter control, should be avoided. Smooth pressure should be used to make all modifications.

main rotor head
Helicopter Main Rotor Head

The collective pitch is the major control for manifold pressure in piston helicopters, and the throttle is the primary control for rpm. The collective pitch control, on the other hand, effects rpm, and the throttle influences manifold pressure; as a result, each is regarded a secondary control of the function of the other. To identify which control to use, both the tachometer (rpm indicator) and the manifold pressure gauge must be examined.

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