What does the angle of attack represent?

The angle of attack is defined as the angle between the chord line of an airfoil (typically a wing) and the direction of the relative airflow. This angle is crucial for understanding lift generation. As the angle of attack increases, the lift produced by the wing also increases until a certain point, commonly referred to as the critical angle of attack. Beyond this angle, airflow begins to separate from the wing surface, leading to a stall condition where lift dramatically decreases.

The concept of angle of attack is integral to aircraft performance. It directly impacts how much lift is generated at different flight conditions and affects the aircraft's stall characteristics. Pilots must be adept at managing the angle of attack during various phases of flight to ensure safe and efficient operations.

In contrast, while the angle between the aircraft and the horizon, the angle of incidence of the wing, and the angle between the wing and the fuselage are all relevant measurements in aviation, they pertain to different aerodynamic principles or aircraft geometry and do not accurately capture the relationship that defines angle of attack.