Which wing design feature helps to reduce the likelihood of a wing-tip stall?

The feature that helps to reduce the likelihood of a wing-tip stall is greater camber at the tip. Camber refers to the curvature of the wing; increasing the camber at the wing tip enhances lift and improves airflow over the wing surface, especially during critical phases of flight such as maneuvering or at lower speeds.

When a wing experiences a stall, it is often the case that the airfoil loses lift first at the wing tip due to the distribution of lift across the wing. By increasing the camber at the tip, the aerodynamic design promotes smoother airflow and delayed stall characteristics, allowing the tip to maintain lift longer than the rest of the wing. This is crucial for maintaining controllability and improving overall aircraft performance.

In contrast to this correct approach, simply increasing wing weight does not directly address aerodynamic performance and could be counterproductive by affecting the aircraft's overall lift-to-weight ratio. Increasing wing length, while beneficial in some respects, does not inherently address the stall behavior at the tips. Sharp leading edges can be beneficial for certain high-speed applications, but they do not fundamentally enhance stall resistance at the tips of a wing. Thus, greater camber at the tip is the most effective design feature in reducing the likelihood of a wing-tip stall.