Winglets are a common feature of commercial airliners. Most commercial airliners don’t have straight wings. If you’ve ever looked out the window while flying, you may recall seeing the tips of the wings curving upward. Known as winglets, these curved wing tips improve fuel efficiency by 6% on average.
What Are Winglets?
Winglets are curved wing tips or extensions. Their origins can be traced back to the end of the 19th century. In 1897, English engineer Frederick Lanchester filed a patent for plate-based wing extensions. Lanchester believed these wing extensions could help to control air vortices.
Today, winglets are found on most midsize and large airplanes. While their design varies, they all consist curved wing tips that promote greater fuel efficiency.
The Basics of Air Vortices
Winglets work by suppressing air vortices. How does this translate into better fuel efficiency exactly? Airplanes generate lift through pressure differential. The air flowing under an airplane’s wings has greater pressure than the air flowing over the airplane’s wings. This pressure differential creates pockets of swirling, fast-moving air known as air vortices.
Air vortices are a source of drag. They create resistance that slows down airplanes during flight. Winglets, however, are designed to minimize vortices so that airplanes encounter less drag.
Winglets and Air Disruption
Winglets essentially disrupt the air at the end of the wings. Air vortices involve high-pressure and low-pressure air meeting at the tips of an airplane’s wings. When left unchecked, the swirling pockets of air create a form of induced drag. Winglets, though, create disruptions where the high-pressure and low-pressure air meet, resulting in less drag.
They don’t prevent air vortices from forming. Rather, winglets work to reduce the size and strength of these air vortices.
Different Types of Winglets
There are many different types of winglets. The Boeing 737 and 757 feature blended winglets. They are characterized by a smooth transition from the wing to the tip.
Some airplanes feature split scimitar winglets. Scimitar winglets still curve upward, but they also curve downward. They essentially split at the end to create a dual-curved design.
Airbus airliners often feature sharklets. Sharklets look like traditional winglets but with a slightly more prominent fin, hence the name.
In Conclusion
Regardless of the shape or style, all winglets work by suppressing air vortices. Air vortices are swirling pockets of air where the high-pressure and low-pressure air meet. They create drag that opposes an airplane’s motion. By suppressing air vortices, winglets allow airplanes to fly with less resistance, which promotes greater fuel efficiency.
