What propeller feature allows for the adjustment of blade pitch?

The feature that allows for the adjustment of blade pitch in a propeller system is known as a constant speed, controllable pitch mechanism. This type of propeller can automatically adjust the blade angle to maintain a consistent rotational speed (RPM), optimizing performance under varying flight conditions.

In a constant speed propeller, the blade pitch can be changed by the pilot or automatically by the engine’s control system, depending on the design. This feature is crucial for maximizing thrust and efficiency during different phases of flight, such as takeoff, climb, cruise, and descent. By adjusting the pitch, the propeller can provide the most effective thrust for the current airspeed and engine power, thus improving fuel efficiency and overall aircraft performance.

Other options, such as fixed pitch, variable speed, and feathering with constant torque, do not have the capability for adjusting blade pitch in the same flexible manner as a controllable pitch system, thereby limiting their effectiveness in varying flight conditions. Variable pitch, constant speed, while similar in concept, typically refers to systems that maintain a specific RPM but do not include the comprehensive control aspects present in a constant speed, controllable pitch propeller.