To produce the same lift while in ground effect as when out of ground effect, the airplane requires which change to angle of attack?

To produce the same lift while in ground effect as when out of ground effect, the airplane requires which change to angle of attack?

• A. A lower angle of attack
• B. A higher angle of attack
• C. The same angle of attack
• D. A variable angle of attack

Answer: (A)

In ground effect, the wing becomes more lift-efficient because the presence of the ground reduces downwash and induced drag. That means for the same angle of attack you generate more lift when close to the surface than you do out of ground effect. So to produce the same amount of lift in ground effect as you do out of it, you don’t need as steep an angle of attack—you can accomplish it with a lower angle of attack. If you kept the same angle of attack, you’d typically get more lift in ground effect, and increasing the angle would increase lift further or bring you closer to stall depending on the aircraft.

In ground effect, the wing becomes more lift-efficient because the presence of the ground reduces downwash and induced drag. That means for the same angle of attack you generate more lift when close to the surface than you do out of ground effect.

So to produce the same amount of lift in ground effect as you do out of it, you don’t need as steep an angle of attack—you can accomplish it with a lower angle of attack. If you kept the same angle of attack, you’d typically get more lift in ground effect, and increasing the angle would increase lift further or bring you closer to stall depending on the aircraft.