What does the pilot do to change the RPM of an engine equipped with a constant-speed propeller when it is operating within the constant-speed range?

What does the pilot do to change the RPM of an engine equipped with a constant-speed propeller when it is operating within the constant-speed range?

• A. Adjust the engine fuel flow.
• B. The pilot moves the propeller pitch control.
• C. Use the throttle to instantly change RPM.
• D. Engage the feather switch.

Answer: (B)

When the propeller is in the constant-speed range, the RPM is controlled by changing the blade angle with the propeller pitch control. The governor automatically adjusts pitch to hold the selected RPM as load or power requests change. So moving the pitch control toward a finer pitch tends to raise RPM, while moving toward a coarser pitch lowers RPM, with the governor doing the automatic tuning to keep the speed steady. The throttle mainly sets engine power, not the stabilized RPM in this range, because the governor maintains RPM by adjusting pitch. The feather switch isn’t used for normal RPM changes; it places the blades in a high-pitch position to reduce drag during an engine-out condition.

When the propeller is in the constant-speed range, the RPM is controlled by changing the blade angle with the propeller pitch control. The governor automatically adjusts pitch to hold the selected RPM as load or power requests change. So moving the pitch control toward a finer pitch tends to raise RPM, while moving toward a coarser pitch lowers RPM, with the governor doing the automatic tuning to keep the speed steady. The throttle mainly sets engine power, not the stabilized RPM in this range, because the governor maintains RPM by adjusting pitch. The feather switch isn’t used for normal RPM changes; it places the blades in a high-pitch position to reduce drag during an engine-out condition.