Fixed-pitch propellers are propellers with which characteristic?

• A. Propellers with variable blade angles.
• B. Propellers with fixed blade angles.
• C. Propellers with feathering capability.
• D. Propellers designed to automatically adjust pitch in flight.

Answer: (B)

Fixed-pitch propellers have blades set to a single, unchangeable angle relative to the plane of rotation; the pitch cannot be adjusted in flight. This means the thrust and efficiency are optimized for a specific operating condition, and power is changed by adjusting engine RPM rather than by changing blade angle. This contrasts with variable-pitch or controllable-pitch props, which allow in-flight changes to blade angle to suit different airspeeds and power settings, and with feathering or automatic pitch systems that are features of those variable-pitch designs. So the defining characteristic is that the blades have fixed blade angles.