Which design feature is used to avoid stalls in the wing?

The design feature that is commonly used to avoid stalls in the wing is wing washout. Wing washout refers to the intentional geometric twist in the wing design, where the angle of incidence decreases from the root of the wing to the tip. This means that the root section of the wing will stall before the tip section.

By having a higher angle of attack at the wing root, the stall will initiate there first, allowing the pilot to maintain aileron control and avoiding a complete loss of control. This characteristic is particularly important for maintaining aileron effectiveness and overall aircraft controllability during high angle-of-attack conditions, as it helps ensure a more benign stall behavior.

While the other features like ailerons, flaps, and slats serve other important roles in aircraft performance and control, they do not directly provide the same stall management benefits that washout does. Ailerons are primarily used for roll control, flaps increase lift during takeoff and landing, and slats enhance airflow over the wing at higher angles of attack but do not specifically facilitate stall management as effectively as washout does.