What does the term "twist" refer to in wing design?

In wing design, the term "twist" specifically refers to a varying angle of incidence along the wing span. This feature is crucial because it helps to enhance the overall aerodynamic performance of the wing. By adjusting the angle of incidence from the root to the tip of the wing, designers can optimize lift distribution and ensure that different sections of the wing achieve the best possible performance throughout various phases of flight.

The application of twist allows the wing to maintain effective lift at a range of angles of attack, helping to prevent stalling in the outer sections of the wing. This characteristic is especially significant during takeoff and landing, where wing performance is critical. By promoting a smoother distribution of lift across the span of the wing, twist enhances control and stability, which can lead to safer and more efficient flight.

In contrast, other aspects of wing design, such as material variation, flexibility, and weight reduction, play important roles as well but do not define the term "twist." Each of these features can impact the wing's performance, but they do not relate directly to the angle of incidence variation that "twist" describes.