If the same angle of attack is maintained in ground effect as when out of ground effect, what happens to lift and induced drag?

If the same angle of attack is maintained in ground effect as when out of ground effect, what happens to lift and induced drag?

• A. Lift increases and induced drag decreases
• B. Lift decreases and induced drag increases
• C. Lift remains the same and induced drag remains the same
• D. Lift increases and induced drag increases

Answer: (A)

Proximity to the ground changes the wing’s wake. When the wing is close to the surface, the ground interferes with the wingtip vortices and reduces the downward deflection of the airflow (downwash). This makes the wing more efficient: for the same angle of attack and airspeed, it generates more lift. At the same time, the weaker downwash means less energy is wasted in the wing’s wake, so induced drag is reduced. So, maintaining the same angle of attack in ground effect produces higher lift and lower induced drag.

Proximity to the ground changes the wing’s wake. When the wing is close to the surface, the ground interferes with the wingtip vortices and reduces the downward deflection of the airflow (downwash). This makes the wing more efficient: for the same angle of attack and airspeed, it generates more lift. At the same time, the weaker downwash means less energy is wasted in the wing’s wake, so induced drag is reduced. So, maintaining the same angle of attack in ground effect produces higher lift and lower induced drag.