Winglets (or wingtip devices) come in many shapes and sizes. Hence, the terminologies used for them differ by aircraft type and manufacturer. Winglets are vertical, canted, or curved devices installed at the wingtips to increase the aircraft’s aerodynamic efficiency.

Aircraft fuel efficiency

Fuel efficiency is directly affected by the magnitudes of drag airliners experience during flight. Apart from the parasite drag (form, interference, and skin friction), a large portion of the aerodynamic drag results from the airflow rolling from the higher-pressure side of the wing to the lower-pressure side, causing wingtip vortices.

Lift-induced drag is generated as a byproduct of the downwash from the vortices, which affects the aircraft’s aerodynamic efficiency. Depending upon the aircraft type and phase of flight, approximately 35 to 40% of the total drag can be associated with lift-induced drag.

Wingtip devices

Wingtip devices improve the aircraft’s performance by managing the pressure distribution as the high-pressure flow wraps around the wingtips. The lift-induced drag on aircraft is reduced by partial recovery of the tip vortex energy through winglets. Depending on the type of device and flight conditions, wingtip devices can improve fuel efficiency by 2-5%.

First wingtip devices

Before the Wright Brothers’ first flight, Frederick Lanchester, an English engineer,…