Winglet

A winglet on a Boeing 757

A winglet is a component that reduces how much fuel airplanes use during flight. It does this by lowering the amount of induced drag.

Explanation of induced drag

Drag happens when air pushes, or exerts force, against a moving object.

However, induced drag happens when air is pushed out from under the plane's wing and to its far edge, known as the wingtip. This air then goes up and over the wingtip, creating a spiral; these spirals are known as wingtip vortices.^[1]

These spirals of air bring more high-pressure air from under the wing to the space above the wing, pulling the wing down and backward. This process is what makes induced drag.

Induced drag increases with the strength of wingtip vortices. Heavier and slower airplanes create stronger wingtip vortices; as a result, they create more induced drag.

Applications

A winglet of a Japanese U-4

To keep high-pressure air under the wings of an airplane, winglets are used. Winglets make it harder for air to go around the wingtips and push the wings down; as a result, the plane's induced drag is reduced.

Winglets are useful in large aircraft that make a lot of induced drag, such as business jets, airliners, and cargo planes.

Winglet Media

The Airbus A350 wingtip device
Line drawing of wingtip vortices behind a conventional wingtip (on the left) and a blended winglet (on the right)
The Ha 137 prototype aircraft, fitted with vertical wing extensions, c.1935–1937
Winglet on KC-135 Stratotanker with attached tufts showing airflow during NASA tests in 1979–1980
Gulfstream V model winglet flutter tests at NASA Langley transonic wind tunnel
Winglet of McDonnell Douglas MD-11F
A Learjet 28/29, the first commercial aircraft with winglets
Wingtip fences are featured on most Airbus legacy models.
The Boeing 787 Dreamliner is an example of raked wingtips utilization.
Boeing 737-8 MAX (N8704Q cn 36988/5788) at 2016 Farnborough Airshow (EGLF / FAB)