Given a constant load factor, which statements about the variation of induced drag with changes of speed and mass are correct or incorrect? 1. When speed decreases, induced drag decreases. 2. When mass decreases, induced drag increases.

• A. 1 and 2 are correct.
• B. 1 is correct, 2 is incorrect.
• C. 1 is incorrect, 2 is correct.
• D. 1 and 2 are incorrect.

Answer: (D)

Induced drag for a given flight condition scales with the square of the lift and inversely with speed. With a constant load factor, lift L is L = nW, so L ∝ W. The classic relation gives D_i ∝ L^2 / (ρ V^2), so D_i ∝ W^2 / V^2, and since weight W ∝ mass, D_i ∝ m^2 / V^2.

This means: as speed decreases, induced drag increases (the 1/V^2 term dominates). As mass decreases, induced drag decreases (the W^2 term gets smaller). Therefore, both statements are incorrect.