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AerodynamicsQuestion 489 of 934

When is the corkscrew effect of the slipstream strongest?

  1. At low propeller speed and high forward speed
  2. At high propeller speed and low forward speed
  3. At cruise speed with a low power setting
  4. During a power-off glide
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Correct answer: At high propeller speed and low forward speed

At high rpm and low airspeed, the spiral is compact and exerts a strong sideward force on the vertical tail.

Source: Pilot's Handbook of Aeronautical Knowledge (FAA-H-8083-25C), Chapter 5: Aerodynamics of Flight — Torque and P-Factor — Corkscrew Effect, page 128

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Questions last reviewed: 18 October 2026