If you have flown anywhere in the past few years you might have noticed an increasing number of airplanes with odd ends to their wings. These ends to the wing are called “Winglets” and they are pretty incredible, but often go unnoticed or unappreciated. The picture above is a United 737 with Split Scimitar Winglets. The “split” implies that there is an upper and lower winglet. The point of these winglets? Increased fuel efficiency, increased wing performance, and decreased drag.
When a wing is generating lift air is passing over and under the wing and different speeds, but things get really interesting at the end of the wing. The air passing under the wing tries to go around the end of the wing and creates a “wingtip vortex.” As the air passes around the end of the wing, it has a tendency to press on the top of the wing. This reduces the effective surface of the wing, decreasing lift and increasing drag. This translates into reduced fuel efficiency.
The winglet blocks this rotation from pressing down on the end of the wing. The result is an increased wing effectiveness. The winglet works to reduce wing-tip drag and increase the lift to drag ratio. The device may seem small, but they serve a huge purpose. United Airlines estimates that a single winglet saves 45,000 gallons of fuel a year! The installation is very easy to retrofit on older planes and majority of new planes delivered come with some type of winglet. Airbus and Boeing both incorporate winglets on many of their aircraft because of increased performance.
The winglet not only improves fuel efficiency, but because it actually makes the whole wing more “effective” planes are able to take off and land on shorter runways more safely, planes are able to carry more weight, and fly farther due to these odd looking devices. Lastly, some airlines have figured out they offer a unique place to advertise. American Airlines, Westjet, and a few others have decided to put their web address on the winglet to help advertise their brand!
Winglets might not be the most interesting thing in the world, but they serve a huge purpose and next time you’re on a plane with Winglets I hope you are able to appreciate what a huge purpose they serve.