What is the purpose of incorporating a dihedral angle in wing design?

Incorporating a dihedral angle in wing design primarily enhances lateral stability and roll resistance. The dihedral angle refers to the upward angle of the wings from horizontal. When an aircraft with dihedral wings experiences a roll due to an imbalance in lift (for example, if one wing encounters more turbulent air), the wing that drops becomes less effective due to the increased angle of attack, while the wing that rises gains more lift. This aerodynamic effect generates a restoring moment—encouraging the aircraft to return to level flight.

The design promotes stability in flight, making it easier to control the aircraft, especially during turns and turbulence. A dihedral angle creates a naturally stabilizing effect; as the wings are positioned to enhance the relationship between lift and roll movements, pilots experience improved ease in maintaining equilibrium during flight.

Other options do not align with this purpose. Improving engine efficiency or optimizing aerodynamic shape are typically related to different design aspects of aircraft, rather than stability. Increasing drag contradicts the goal of effective design, as drag generally reduces the efficiency of flight. Therefore, the dihedral angle is explicitly meant to ensure the aircraft's stability and response to rolling events, making it a key feature in wing design for various types of aircraft.