What occurs in ground effect with regard to induced angle of attack and drag?

In ground effect, the relationship between induced angle of attack and drag is particularly significant for aircraft performance during takeoff and landing phases. When an aircraft is flying close to the ground, the interaction of the wing with the ground alters the airflow patterns around the wings. As a result, the lift produced by the wings increases while the induced drag decreases.

The primary reason this happens is that the closer proximity to the ground reduces the strength of the wingtip vortices that are created as the aircraft generates lift. These vortices are responsible for creating downwash, which in turn, affects the effective angle of attack; as the aircraft nears the ground, the downwash is less severe, enabling the wings to operate more efficiently. Consequently, this leads to a decrease in the induced angle of attack required to maintain lift and a corresponding reduction in induced drag, allowing the aircraft to fly more effectively with less power or thrust needed.

This phenomenon explains why during takeoff and landing within ground effect, pilots can experience improved performance characteristics such as increased lift and reduced drag, contributing to smoother operations near the ground.