What is a winglet's primary function?

The primary function of a winglet is to reduce drag. Winglets are vertical extensions at the tips of wings designed to address vortex formation. When an aircraft is in flight, especially during cruise, the pressure difference between the upper and lower surfaces of the wing creates vortices at the wingtips. These vortices induce drag, known as induced drag, which negatively impacts fuel efficiency and overall aerodynamic performance.

By incorporating winglets, the airflow around the wingtips is altered, effectively minimizing the strength of these vortices. This reduction in vortex strength decreases induced drag, allowing the aircraft to maintain lift with less energy. Consequently, winglets contribute to enhanced fuel efficiency and performance during both cruise and climb phases of flight, aligning with their primary design purpose.

While increasing wing span, improving landing stability, and enhancing climb performance may have indirect benefits associated with the use of winglets, the main goal is specifically the reduction of drag, which leads to more efficient flight.