There are a number of elements in aircraft fuselages that may go unnoticed by non-experts but which are still extraordinarily important. A good example are the small structures out on the tips of their wings known as ¨winglets¨ and ¨sharklets¨. Designed to boost a plane´s aerodynamic efficiency (LINK) and flight range and reduce its fuel consumption, the most recognisable of these have the shape of a fin folded upwards, but there are some variations.
A Bit of History
As almost always, the military blazes trails when it comes to implementing new developments. Typically, a new element is tested first by military aviation, and then once its effectiveness is proven, it becomes utilised by the commercial sector.
In this case the story begins during World War II, although there´s no specific moment to point to – instead, for precedents we need to go back to the first decade of the 20th century. But it was in the last great world conflict where the first wingtip devices were really put to the test, as an innovation made on small jet planes of the German Luftwaffe, in which case the tips of the wings were folded downwards.
Its appearance in civilian aviation began in the 1970s, when Boeing began experimenting with a model called the KC-135. Then in 1977 the first civilian winglets were incorporated into a so-called executive business plane, the Learjet 28.
In 1986, a very light aircraft called the Model 76 Voyager, created in the United States, achieved a milestone: flying around the world without refueling, and among its features was a wing structure with two winglets. In commercial aviation, the first aircraft to use wingtip devices to improve its aerodynamics was the Airbus A300 – specifically wingtips, a type of winglets with a vertical plane opposite the tip of the wing and extending both up and down.
We have, therefore, the first downward wingtip devices (known as “Hoemer tips”; later, winglets that were simply small planes raised upwards by 90 degrees; later wingtips appeared, and after their appearance in the Airbus, all commercial aviation began to use them, as their effectiveness in flight and their energy savings was amply demonstrated.
Types of Wingtip Devices
Today there are different types of wingtip devices; in fact, the world´s two largest manufacturers,give theirs a different name: Boeng´s are winglets whilst Airbus refers to them as sharklets.
The differences between devices have to do with the research and development of each company, which implements improvements as aeronautical engineering evolves. These days, following are the main types of wingtip devices:
Canted Winglet
A fin placed at an angle with respect to the plane that forms the wing. The aircraft´s size, characteristics, and performance will determine the size of the winglet, as well as the angle at which it´s placed.
Blended Winglet
A variation of the canted winglet which instead of an angle describes an ascending curve to improve the aerodynamics of the aircraft (this is essentially the sharklet manufactured by Airbus).
Wingtip Fence
Also made by Airbus, it´s a kind of plane perpendicular to the wing, as we mentioned above.
Raked Wingtip
Used by, for example, the Airbus A350, this device is part of the plane and bends backwards, similar how the wings of seagulls do when they fly.
Split Scimitar
Like the wingtip fence, this is a double device, ascending and descending. But here they ´re curved one upwards and the other downwards.
How Wingtip Devices Help
We´ve already hinted at some of the major advantages for commercial aircraft, but here we lay it all out:
Reduction of Fuel Consumption
It´s estimated that winglets or sharklets can reduce an aircraft’s fuel costs by around 5 percent – which means not just saving money but lowering its carbon footprint.
Improvement in Aerodynamic Stability
The extension of the plane upwards avoids making longer wings to reduce the turbulence generated at the tips of the semi-wings, whereas lengthening the wings would increase the weight of the ship and decrease its efficiency.
All in all, these devices result in improvements in safety, efficiency, speed, and the overall flight experience – in short, a win win win win!