Flap angle

Flap Angle. The angle between the chord of the wing and the chord of the flap. Flaps are often lowered about 5° to assist take-off and usually about 30° to 45° for landing.

Flap activation increases the angle of attack across the wing / flap section. At 10 degrees, more lift than drag is produced. As the flap angle is increased more drag and less lift is produced for each increment of deployment.