Zero lift axis
From Wikipedia, the free encyclopedia
An angle of attack of an aerofoil that produces no lift. (Coefficient of lift, CL is zero.) For asymmetric aerofoils, this angle is negative for the CL to be zero. (See diagram at right.) For symmetric aerofoils the zero lift axis is aligned with the chord line of the wing.
Flying vertical lines in Aerobatics requires the aircraft to fly perpendicular to the ground. This is defeated if the wing produces any lift (positive or negative) which causes the airplane to pitch onto its back or underside.
