The tip is the end part of the wing structure, plumage or propeller blades of aircraft.
The wingtip begins at the place where the wing spars end and, as a rule, is a hollow monocoque / semi-monocoque structure, in which navigation fire (lights) and, often, static charge (lightning) strikers are located. The tip of the keel and stabilizer have a similar design.
At the wingtips can be installed aerodynamic tips , ( end wings , winglets ( English winglet "wing"), end washers or Whitcomb washers , sharklets - small additional elements on the ends of the plane of the wing of the aircraft in the form of wings or flat washers, which serve to increase effective wing span , reducing the inductive resistance created by the vortex breaking off from the end of the wing and, as a result, increasing the lifting force at the end of the wing. This is its scope. Winglets increase fuel economy in airplanes or flight range in gliders . At present, the same types of airplanes can have different wingtips. For example, sharklets raise the end of the wing.
Content
History and Development
Richard Whitcomb, an aviation specialist and engineer, an employee at NASA , was one of the first researchers to study the influence of wingtip shapes on the aerodynamics of an airplane. In the early 1970s. he constructed a wingtip extending perpendicularly up and down from the wing plane.
On passenger aircraft, aerodynamic tips were first used on the 1985 Boeing 747-400 . Since 2009, this design has been used on the wings of medium-range Airbus A-320 aircraft.
In the early 1990s. Louis Gratzer, chief aerodynamics specialist at Aviation Partners, invented and patented the “blended winglet,” a mated wing that bends smoothly upward along an arc of large radius and has a large elongation. The very first use of new design wings for the modernization of the Gulfstream II business jet in 1991 reduced fuel consumption by 7%. Such large-scale savings due to modernization turned out to be unprecedented in the history of aviation, except for the alteration of the entire aircraft or remotorization.
Of the mass-produced or produced Russian and Soviet aircraft, aerodynamic wingtips are Su-80 , Tu-204/214 , Tu-334 , Il-96 and Ukrainian An-158 and An-178 . Also, the wings on the tips were supposed to be used in the design of the Yak-44 and Il-106 aircraft [1] . In 1986, the Xian Y-7 variant (the Chinese version of the An-24 ) was created with aerodynamic tips [2] . The Chinese also use completely original winglets at the tip of the Y-5C ( An-2 ), consisting of three vertical wings.
Winglets are a mandatory requirement of the London City airport for aircraft, so when in 2016 the Irish airline CityJet was the first in Europe to purchase Russian Superjet SSJ-100 aircraft, it demanded that Sukhoi Civil Aircraft modernize this model and make horizontal winglets [1 ] .
Principle of Operation
The lifting force of the wing is formed due to the pressure difference under the wing and above the wing. Due to the pressure difference, part of the air flows over the edge of the wing from the high-pressure region from below to the low-pressure region from above, forming an end vortex. The energy of motion is spent on the formation of a vortex, which leads to the appearance of an inductive resistance force. The terminal vortex also leads to a redistribution of the lifting force along the wing span, reducing its effective area and elongation, and reducing aerodynamic quality . The installation of aerodynamic tips helps to achieve the optimal shape of the distribution of lift.
The disadvantages of using wingtips are a significant increase in the effect of wind on the aircraft during take-off and landing, as well as a more rigid chatter when flying in a turbulent atmosphere.
Ridge Ends
The ridge tips are the horizontal tips of the wings, having a greater sweep angle than the main part of the wing. The main purpose of such endings is to increase fuel economy, improved performance during climb, reducing the take-off length during take-off. Ridge tips reduce the inductive drag of the wing. Tests of these tips in NASA and Boeing showed that fuel efficiency with such tips was 5.5% versus 3.5-4.5%, which provided the usual vertical tips. Ridge tips are already in use on the Boeing 767 , Boeing 777 , Boeing 787 , Boeing 747-8 and Airbus A350 .
Gallery
Various airplanes and gliders with aerodynamic wingtips:
Rutan VariEze , the first aircraft to use winglets for the first time in 1975
Learjet 28/29
McDonnell Douglas MD-11
IL-96
Raytheon Hawker 800 SP
Rutan long-ez
DG Flugzeugbau DG-808
Boeing 787 with ridge tips.
Aer Lingus logo on Airbus A330 Winglet
Boeing 737-800
Tu-204
Airbus A350
Airbus a340
Two Bombardier CRJ-200
Boeing 737-800
Boeing 737-800 with two-sided wingtips Split Scimitar.