Which blade angle minimizes drag when the engine is shut down?

• A. Zero-no thrust
• B. Positive-thrust
• C. Negative-reverse thrust
• D. Feather-minimize drag when engine shut down

Answer: (D)

When the engine is shut down, the propeller can windmill and create significant drag unless the blades are positioned to shed that drag. Feathering the propeller does exactly that: it moves the blades to a high pitch so they present the smallest possible surface to the oncoming air (nearly edge-on). This dramatically reduces aerodynamic drag and the tendency to windmill, helping maintain the aircraft’s glide and overall efficiency with the engine off. Other blade angles would either catch more wind and add drag or produce thrust cues that aren’t useful when the engine isn’t running, whereas feathering minimizes drag effectively in this situation.