Wing tips

A wing tip (or wingtip) is the part of the wing that is most distant from the fuselage of a fixed-wing aircraft.

Because the wing tip shape influences the size and drag of the wingtip vortices, tip design has produced a diversity of shapes, including:

Winglets have become popular additions to high speed aircraft to increase fuel efficiency by reducing drag from wingtip vortices. In lower speed aircraft, the effect of the wingtip shape is less apparent, with only a marginal performance difference between round, square, and Hoerner style tips The slowest speed aircraft, STOL aircraft, may use wingtips to shape airflow for controlability at low airspeeds.

Wing tips are also an expression of aircraft design style, so their shape may be influenced by marketing considerations as well as by aerodynamic requirements.

Wing tips are often used by aircraft designers to mount navigation lights, anti-collision strobe lights, landing lights, handholds, and identification markings.

Wing tip tanks can act as a winglet and distribute weight more evenly across the wing spar.

On fighter aircraft, they may also be fitted with hardpoints, for mounting drop tanks and weapons systems, such as missiles and electronic countermeasures. Wingtip mounted hose/drogue systems allow Aerial refueling of multiple aircraft with separation.

Aerobatic aircraft use wingtip mounted crosses for visual attitude reference. Wingtip mounted smoke systems and fireworks highlight rolling aerobatic maneuvers. Some airshow acts feature the pilot touching or dragging the wingtip along the ground.

Aircraft with a single main landing gear or very high aspect ratio wings such as gliders, may place small landing gear in the wingtips. Some uncommon designs,like the Rutan Quickie, and Convair XFY placed the main landing gear in the wingtips. Some early World War I aircraft used wooded skids on the wingtips to minimize damage on ground looping incidents.

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Wikipedia