FAA Commercial Pilot Airplane (CAX)Aerodynamics and PerformanceMedium
An airplane's 1G stall speed is 50 knots. During a pull-up from a dive, the pilot imposes a load factor of 2G. What is the airplane's stall speed during this maneuver?
- A70.7 knots
- B57.7 knots
- C100.0 knots
- D61.2 knots
Show answer & explanationAnswer & explanation
Correct answer: A. 70.7 knots
Accelerated stall speed is calculated as Vs × √n, where n is the load factor. Here, Vs = 50 × √2 = 50 × 1.414 = 70.7 knots. This shows that even in a straight pull-up (not just a turn), increased load factor raises the stall speed.
Why the other options are wrong
- B. Incorrect intermediate calculation, does not match √2 multiplier.
- C. Incorrectly doubles the stall speed instead of applying the square root.
- D. Does not correctly apply the square root of load factor.
Accelerated Stall Speed (Pull-Up)
Stall speed increases with the square root of load factor during any maneuver imposing G-forces, not just turns.
- Formula: Vs(accelerated) = Vs(1G) × √n
- Applies to pull-ups, turns, and turbulence
- Higher G-load always raises the stall speed
Memory trick: Square root the G's to find the stall's new degrees (of speed).