Increasing airfoil speed results in what for lift?

Increasing airfoil speed results in what for lift?

• A. Lift increases
• B. Lift decreases
• C. Lift remains unchanged
• D. Lift is unpredictable

Answer: (A)

Increasing airfoil speed raises the dynamic pressure acting on the wing, which increases lift. Lift can be expressed as L = q S Cl, where q = 1/2 ρ V^2 is the dynamic pressure. As velocity increases, q grows with the square of V, so lift increases (assuming the angle of attack and air density stay about the same, so Cl doesn’t change dramatically). In practical terms, doubling speed roughly quadruples lift if Cl remains constant. Lift doesn’t decrease or stay unpredictable simply due to speed, though Cl can change with angle of attack—the main takeaway is that higher speed boosts lift because of higher dynamic pressure.

Increasing airfoil speed raises the dynamic pressure acting on the wing, which increases lift. Lift can be expressed as L = q S Cl, where q = 1/2 ρ V^2 is the dynamic pressure. As velocity increases, q grows with the square of V, so lift increases (assuming the angle of attack and air density stay about the same, so Cl doesn’t change dramatically). In practical terms, doubling speed roughly quadruples lift if Cl remains constant. Lift doesn’t decrease or stay unpredictable simply due to speed, though Cl can change with angle of attack—the main takeaway is that higher speed boosts lift because of higher dynamic pressure.