What is the purpose of dihedral in aircraft design?

The purpose of dihedral in aircraft design is primarily to enhance lateral stability. Dihedral refers to the upward angle of the wings relative to the horizontal plane. When an aircraft has a dihedral angle, the wings are positioned in such a way that they help counteract any rolling motion caused by turbulence or asymmetrical loading. If the aircraft begins to roll to one side, the wing on that side will experience a higher angle of attack, which increases lift on that wing, while the wing on the opposite side will experience a lower angle of attack, resulting in decreased lift. This differential creates a restoring moment that helps the aircraft return to level flight, thus enhancing overall stability.

This aspect of dihedral contributes significantly to the aircraft's aerodynamic behavior, particularly during turns and in response to external disturbances. In contrast, the other options relate to different aerodynamic principles that do not directly pertain to the specific role of dihedral in maintaining lateral stability.