Lift, angle of attack and the stall

The lift equation

L = C_L × ½ρV² × S. The lift coefficient C_L depends mainly on the angle of attack (the angle between the chord line and the relative airflow) and on the wing's shape.

C_L rises almost linearly with angle of attack, then curves over to C_L max at the critical angle of attack. Beyond it the airflow separates from the upper surface and lift falls: the stall. For a given configuration a wing stalls at the same critical angle of attack at any weight or (low) speed; at high Mach number, or with ice on the wing, it stalls at a lower angle.