Winglets: Types, Benefits & Differences | Aircraft Aerodynamics

[Hatty]

I have always known quite a bit about aircraft and aerodynamics, but there is something that I have never quite figured out. What is the difference between raked wingtips, blended winglets, wingtip fences, etc? I am guessing that they each have traits that benifit certain aircraft over others, but what are they?

 

[ajSpades]

Winglets, raked (scimitar) winglets, blended winglets, etc. are all about increasing the efficiency of the wing generating lift. On conventional wings there is a circulation of air from the bottom of the wing (higher pressure) around the wingtip to the top of the wing (lower pressure). This circulation increases drag as well as producing powerful vortices that can disrupt nearby aircraft.

Winglets are one (but not necessarily the best) way to mitigate this circulation. Putting a physical barrier (vertical winglets) on the tip of the aircraft helps block the flow of air. Raked (scimitar) winglets are much more efficient and require much less structure to achieve what winglets do.

One reason a lot of heavier aircraft lately have winglets is that they are easy to add on. You are basically putting a flat-plate at the wingtip. Newer transport aircraft, most notably the Boeing 787, will be incorporating raked (scimitar) wingtips.

 

[ravenprp]

You are correct in thinking that each type of winglet has its own unique benefits and is suited for different aircraft. Let's break down the different types of winglets and their respective advantages.

1. Raked Wingtips: These are angled extensions at the end of the wing that are designed to reduce drag and improve fuel efficiency. They work by reducing the strength of the wingtip vortex, which is a swirling air current that forms at the tip of the wing. Raked wingtips are typically found on larger aircraft, such as the Boeing 787 Dreamliner, and are most effective at high speeds.

2. Blended Winglets: These are curved extensions at the end of the wing that blend smoothly into the wing. They work similarly to raked wingtips by reducing drag and improving fuel efficiency. However, blended winglets are more versatile and can be found on a variety of aircraft, from smaller regional jets to larger commercial planes.

3. Wingtip Fences: These are vertical surfaces attached to the wingtip that help to control the spanwise flow of air. This reduces the strength of the wingtip vortex and improves the overall aerodynamics of the wing. Wingtip fences are commonly seen on smaller aircraft, such as the Cessna Citation, and are most effective at low speeds.

Each of these winglet types has its own unique shape and purpose, but they all work towards the same goal of improving aerodynamics and reducing drag. The choice of winglet will depend on the specific design and needs of the aircraft. For example, raked wingtips are more effective at high speeds, while wingtip fences are better suited for slower speeds.

In addition to their aerodynamic benefits, winglets also have other advantages such as reducing fuel consumption, increasing range, and improving stability and control. They can also help to reduce noise and emissions, making them beneficial for both the aircraft and the environment.

In summary, the different types of winglets each have their own strengths and are suited for different aircraft. It is important for aircraft designers to carefully consider the needs and specifications of their aircraft when choosing a winglet type, in order to maximize its benefits and improve overall performance.