What is the primary purpose of fly weights in a constant speed propeller-equipped aircraft?

The primary purpose of fly weights in a constant speed propeller-equipped aircraft is to regulate the flow of engine oil to and from the propeller. Fly weights are part of the governing mechanism that maintains the desired propeller blade angle based on engine RPM. When the engine RPM exceeds a predefined limit, the centrifugal force acting on the flyweights causes them to move outward, engaging a mechanism that allows engine oil to flow into the propeller hub, which in turn changes the blade pitch to a finer angle. This adjustment helps limit the RPM and maintain optimal performance, ensuring the propeller operates efficiently at varying flight conditions.

While enhancing fuel efficiency and determining engine RPM are important aspects of propeller operation, the specific function of fly weights is directly tied to regulating oil flow to modify blade pitch. In constant speed propellers, pitch control is achieved through a combination of engine speed regulation and oil flow management, making the correct association with oil regulation pivotal in understanding how these components work together in maintaining safe and effective aircraft performance.