What is a constant-speed propeller designed to do?

A constant-speed propeller is designed to automatically adjust the pitch of the propeller blades in order to maintain a selected engine RPM despite changes in airspeed or engine power settings. This capability allows the pilot to optimize engine performance by ensuring that the engine runs efficiently, and it helps maintain a steady thrust level appropriate for the aircraft's operating conditions.

When the engine RPM is set to a specific value, the constant-speed propeller changes its blade angle to either decrease or increase thrust as needed, depending on whether the aircraft is climbing, cruising, or descending. This not only improves performance during various phases of flight but also contributes to overall engine efficiency and responsiveness.

While maximizing fuel efficiency is an important benefit of using a constant-speed propeller, it is not its primary function. Its main role lies in the ability to adjust engine RPM and thrust based on the pilot's settings and the demands of flight. The other options, such as increasing weight tolerance or enhancing drag performance, do not pertain to the purpose of a constant-speed propeller and are not relevant to its design or function.