If the unaccelerated stall speed is 60 knots, what is the stall speed under a load factor of 2 Gs?

If the unaccelerated stall speed is 60 knots, what is the stall speed under a load factor of 2 Gs?

• A. 84 knots
• B. 60 knots
• C. 100 knots
• D. 120 knots

Answer: (A)

Stall speed rises with load factor because the wing must generate more lift to support the heavier load. At stall, lift equals weight, and with a higher load factor n, the required lift becomes n times the weight. Since lift is proportional to V^2 for a given wing (L = 0.5 ρ V^2 S Cl, with Cl,max fixed at stall), increasing the required lift means V must increase as the square root of n. This gives Vstall = Vs1 × sqrt(n). With an unaccelerated stall speed of 60 knots at 1 g and a load factor of 2 g, the stall speed is 60 × sqrt(2) ≈ 84.9 knots. So the best answer is about 84 knots. Choosing the other values would ignore the sqrt(n) relationship: 60 knots would ignore the higher load factor, while 100 or 120 knots would imply a larger or different scaling than dictated by V^2 ∝ n.

Stall speed rises with load factor because the wing must generate more lift to support the heavier load. At stall, lift equals weight, and with a higher load factor n, the required lift becomes n times the weight. Since lift is proportional to V^2 for a given wing (L = 0.5 ρ V^2 S Cl, with Cl,max fixed at stall), increasing the required lift means V must increase as the square root of n. This gives Vstall = Vs1 × sqrt(n).

With an unaccelerated stall speed of 60 knots at 1 g and a load factor of 2 g, the stall speed is 60 × sqrt(2) ≈ 84.9 knots. So the best answer is about 84 knots.

Choosing the other values would ignore the sqrt(n) relationship: 60 knots would ignore the higher load factor, while 100 or 120 knots would imply a larger or different scaling than dictated by V^2 ∝ n.