Wingtip device

Wingtip devices are usually intended to improve the efficiency of fixed-wing aircraft. There are several types of wingtip devices, and though they function in different manners, the intended effect is always to reduce the aircraft's drag by altering the airflow near the wingtips. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without materially increasing the wingspan. An extension of span would lower lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan (e.g., available width at airport gates).

Wingtip devices increase the lift generated at the wingtip (by smoothing the airflow across the upper wing near the tip) and reduce the lift-induced drag caused by wingtip vortices, improving lift-to-drag ratio. This increases fuel efficiency in powered aircraft and increases cross-country speed in gliders, in both cases increasing range.

Winglets are employed on many aircraft types, such as:

• Rutan VariEze, the first aircraft to use winglets (1975)
• Learjet 28/29, the first production jet aircraft to use winglets (1977)
• Glaser-Dirks DG-303, an early glider derivative design, incorporating winglets as factory standard equipment
• Airbus A310-300, the first airliner to feature wingtip fences (1985)
• Boeing 747-400, the first mainline airliner to feature winglets (1988)
• Ilyushin Il-96, first Russian and modern jet to feature winglets (1988)
• Tupolev Tu-204, first narrow body aircraft to feature winglets (1994)