AerodynamicsQuestion 484 of 934

Why is a fixed-pitch propeller a compromise?

  1. It is efficient at all airspeeds but only one rpm
  2. It is efficient at all rpm but only one altitude
  3. It is efficient at one airspeed and rpm pair
  4. It cannot produce thrust at cruise speed
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Correct answer: It is efficient at one airspeed and rpm pair

The pilot cannot change the airspeed and rpm combination in flight.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 5: Aerodynamics of Flight — Basic Propeller Principles, page 126

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Questions last reviewed: 18 October 2026