How is the speed of a constant-speed propeller changed in flight?

• A. by adjusting engine throttle
• B. by changing propeller diameter
• C. by changing the load tension against the flyweights in the governor
• D. by altering airspeed

Answer: (C)

In a constant-speed propeller, speed is controlled by changing the blade pitch through the propeller governor, not by simply shifting throttle. The governor senses engine RPM with its flyweights and uses a calibrated spring to set the desired speed. By altering the load on the propeller—the tension they feel—the governor moves the pitch to increase or decrease RPM. Increasing the load (more blade angle) slows the propeller; decreasing the load (less blade angle) lets it speed up. So, in flight, you change prop speed by adjusting the load on the governor’s flyweights, which changes the blade pitch.