How does total drag change in straight and level flight at constant mass as speed increases from stall to Vne?

• A. Remains constant
• B. Initially decreases, then increases
• C. Continuously decreases
• D. Initially increases, then decreases

Answer: (B)

Total drag in level flight with constant weight is the sum of induced drag and parasite drag. Lift must balance weight, so as speed increases, the lift coefficient falls. Induced drag is tied to the square of lift coefficient, so it drops quickly with speed (roughly inversely with velocity squared). Parasite drag, on the other hand, grows with speed because dynamic pressure increases and drag due to the airplane’s shape becomes more significant, so it increases roughly with velocity squared.

At low speeds near stall, induced drag dominates, keeping total drag high. As you speed up, induced drag falls faster than parasite drag rises, so total drag decreases. But as speed continues to increase, parasite drag becomes the dominant contributor and causes the total drag to rise again. The minimum drag occurs somewhere between stall and Vne, where the two components balance. Therefore, total drag decreases initially, then increases as speed moves from stall toward Vne.