While looking out the aircraft window, you might be wondering what are those fins on the airplane wingtip. Some look like tails, some look like an arrow, some are large, some are small, and some are just pointed at the edge. Those are called winglets, and they are wingtip devices that improve the efficiency of aircraft by reducing drag.
So how does a wingtip device or winglet work?
Drag is known as the force acting opposite to the relative motion of any object moving with respect to a surrounding fluid, but for the case of aircraft, air.
A winglet or wingtip device helps reduce the wake of air vortices when air moves at different speeds at the top or bottom of the wing. These vortices on the edge of the wing create the drag, thus, reducing the efficiency of aircraft as more power is used. By cutting down this vortex which then reduces drag, less power is used, hence making the aircraft more efficient.
More than just making the aircraft look more slick and stylish, wingtip devices have brought some serious fuel savings and have reduced emissions by 3 to 6%.
Different aircraft have wingtip devices of different shapes and sizes.
Winglets found on Airbus aircraft
The Airbus A320 family uses two types, a wing fence and a blended wingtip which Airbus terms as “sharklet”.
The wing-fence seen on the photo of an AirAsia A320 above came out in earlier versions of the aircraft. While both a wing-fence and sharklet serve the same purpose, the latter has proven to make the A320 more efficient.
Today, all A320 aircraft family uses ‘Sharklets’ or Airbus’ own version of a blended wingtip.
Boeing 737 wingtip decices
Most of the New Generation version of the Boeing 737 uses the blended wingtip similar to that of the Airbus sharklet. However, some versions of the NG before the 737 MAX were already equipped with a newer type of wingtip device called a “Split-Tip Winglet”.
Later versions of the Boeing 737NG uses Split-Scimitar Wingtips seen in the picture above. Far away, it may seem like the wingtip splits but if you would look closely, you would notice a main blended wingtip with an added fin pointing downwards. On the other hand, the 737 MAX’s wingtip splits into two. Below is a comparison of both. The left is a wingtip of a 737 MAX and the right belongs to a 737NG.
Canted and raked wingtips
The Boeing 747-400, Airbus A330, and A340 use the canted wingtip. The Jumbo jet was first to introduce the canted-wingtip which has helped increase the range by 3.5% compared to its previous model, the 747-300. Airbus then followed by also using canted wingtips on its A330 and A340 in 1992 and 1993.
Almost all of Boeing’s widebody aircraft being released today like 777, 787, and the 747-8 uses raked wingtips where the tip has a greater sweep and much-pointed edge than the rest of the wing. According to Boeing, this improves fuel efficiency, take-off, and climbing performance.
Wingtip devices or winglets are not there primarily for aesthetic purposes only, but they are there to improve an aircraft’s performance and efficiency. More than 8,000 aircraft now flying around the world make use of wingtip devices. This has resulted in almost 20 billion liters of jet fuel saved, avoiding over 56 million tonnes of CO2 emissions since 2000.
