The angle between the chord line of an airfoil and the relative wind is called what?

The angle formed between the chord line of an airfoil and the direction of the relative wind is known as the angle of attack. This angle is crucial in determining the lift generated by the airfoil; as the angle of attack increases, the lift typically increases up to a certain point before flow separation leads to stall.

Understanding angle of attack is vital for pilots and engineers as it directly influences the performance of an aircraft. When pilots adjust the pitch of the aircraft, they effectively change the angle of attack, impacting the lift and drag forces acting on the airfoil. This concept is fundamental in aerodynamics, affecting everything from takeoff to cruising to landing.