How does weight affect the stall angle and stall indicated airspeed (IAS) of an aircraft?

Weight has a significant impact on the aerodynamic performance of an aircraft, particularly concerning the stall angle and stall indicated airspeed (IAS).

When an aircraft's weight increases, the stall speed, which is the minimum speed at which the aircraft can fly without stalling, also increases. This occurs because heavier aircraft require a greater amount of lift to counteract the increased weight. The lift generated by the wings is a function of airspeed, so to produce the necessary lift to maintain level flight under increased weight, the aircraft must achieve a higher speed, thereby increasing the stall speed.

On the other hand, the stall angle, which is the angle of attack at which the aircraft will stall, remains relatively constant regardless of the weight of the aircraft. This angle is determined by the wing's aerodynamic design and characteristics, such as its camber and airfoil shape, rather than the aircraft's mass. Therefore, while the stall speed increases with added weight, the stall angle does not alter significantly.

As a result, the correct understanding is that while the stall angle remains constant, the stall speed increases with the increase in weight. This leads to the conclusion that stall speed is variable based on weight, while the stall angle primarily remains constant across different loading conditions.