Which effect is achieved by winglets on aircraft wings?

• A. Reduce induced drag by weakening wingtip vortices
• B. Increase wingtip vortices to stabilize flight
• C. Increase wing weight for better performance
• D. Decrease lift at cruise

Answer: (A)

Winglets cut induced drag by weakening the wingtip vortices that form when the wing generates lift. As air streams off the wingtip, it curls into a strong vortex that creates downwash behind the wing and adds to drag. Winglets act like small vertical surfaces at the tip, redirecting some of that swirling airflow outward and upward. That reduces the strength of the wingtip vortex and, in turn, the downwash and induced drag. Because the winglets effectively increase the wingspan’s effective span, the apparent aspect ratio goes up, making lift more efficiently produced for a given drag. The practical result is improved fuel efficiency and range, especially during cruise when induced drag is a larger portion of total drag. They don’t function by increasing vortices, they don’t add wing weight for better performance, and they don’t decrease lift at cruise.