At what angle of attack does an airfoil stall, regardless of gross weight?

The angle of attack at which an airfoil stalls is a fundamental characteristic of that airfoil and remains consistent regardless of factors like gross weight, airspeed, or altitude. This angle, known as the critical angle of attack, is determined by the airfoil's design and its shape.

When the angle of attack is increased to this critical point, the airflow begins to separate from the upper surface of the airfoil, leading to a loss of lift and the onset of stall. This phenomenon occurs because the stall is related to the airflow characteristics over the wing rather than the aircraft's weight, ensuring that all airfoils of the same design will experience stall at the same angle of attack. Knowing the critical angle of attack is crucial for pilots, as it helps them avoid stalls by maintaining their flight operations within safe limits.