Awing tip (orwingtip) is the part of the wing that is most distant from thefuselage of afixed-wing aircraft.
Because the wing tip shape influences the size anddrag of thewingtip vortices, tip design has produced a diversity of shapes, including:
Winglets have become popular additions to high speed aircraft to increasefuel 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.[1] The slowest speed aircraft,STOL aircraft, may use wingtips to shape airflow for controllability at low airspeeds.
Wing tips are also an expression of aircraft design style, so their shape may be influenced bymarketing considerations as well as byaerodynamic requirements.
Wing tips are often used by aircraft designers to mountnavigation lights, anti-collisionstrobe lights,landing lights, handholds, and identification markings.
Wing tip tanks can act as a winglet and distribute weight more evenly across the wing spar.
Onfighter aircraft, they may also be fitted withhardpoints, for mountingdrop tanks and weapons systems, such asmissiles andelectronic countermeasures. Wingtip mounted hose/drogue systems allowAerial 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 asgliders, may place small landing gear in the wingtips. Some uncommon designs, like theRutan Quickie, andConvair 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.
Several amphibious aircraft such as theConsolidated PBY Catalina, use retractable wingtips as floats.
Moveable wingtips can affect the controlability of a wing.Wing warping the ends of the wing, produced roll control on the earliest of aircraft such as theWright Flyer. TheNorth American XB-70 Valkyrie raised and lowered its wingtips in flight to adjust its stability in supersonic and subsonic flight.
Wingtips can also house the power plant or thrust of an aircraft. TheEWR VJ 101 used tip mounted jets, theV-22 uses tilting wingtip mounted engines, and theHarrier uses wingtip thrust for stability while hovering.
Rotary wing aircraft wingtips may be swept or curved to reduce noise and vibration. Some rotary wing aircraft place their propulsion in wingtiptip jets.
Due to limited space withinnaval vessels, manynaval aircraft possessfolding wings and wingtips for storage purposes, minimizing the area they occupy within the ship'shangar. Some aircraft operated on land may possess a similar mechanism to allow them to fit within a small, oftenreinforced, hangar.
TheBoeing 777X will feature 3.5 m (11 ft) folding wingtips supplied byLiebherr Aerospace fromLindenberg. The mechanism was demonstrated forAviation Week at theBoeing Everett Factory in October 2016. The folding takes 20 seconds to complete.[citation needed]
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