Have you ever wondered why wingtips on modern airplanes are vertical? How does something relatively small can affect big airliner? It's time to talk about the winglets.
To understand why winglets are necessary, we have to talk about basic physics. Just like the boats leave swirling trails on the water, objects in air disturb it as well. The turbulence behind the planes looks really similar to the vortices over the ships.
Now, imagine the wing. As you probably know, the lift is achieved by the difference in pressure, between the lower part, with relatively low air velocity, and the upper part, where air travels very fast. These two masses of air meet at the end of the wing.
Everything in Nature has to be balanced. High and low pressure tries to mix and stabilize as one air mass. While this process occurs, the air is swirling around and create the vortex. Because vortices create a significant amount of drag the fuel penalty is relatively high. Jet requires more thrust that, consequently, requires more fuel and puts a lot of wear on the engines. We will show you the most typical that we see in LINETECH during maintenance.
Every year we maintain dozens of Airbus products. All of the A320 family aircraft are equipped with standard wingtips, that disturb the vortices. These small devices are light, require virtually no maintenance and are just fine. However, they are not as efficient as solutions provided by competitors and the third-party manufacturers, which pushed Airbus towards Boeing-style winglet called "Sharklet", as seen on A320NEO family and most of the new Current Engine Option A320, A319, and A321's.
Speaking of Boeing, the winglet created by Seattle based aviation giant is by far most recognizable. Recently Boeing pushed the idea even further, creating split scimitar winglet. It has opposite, small fin below. The scimitar means that the tip is even smaller and aerodynamic to reduce induced drag to a minimum. The ideas of the split scimitar winglets were used to design new wingtips of a Boeing 737 MAX.
In LINETECH we had an opportunity to work with both Split Scimitar Winglet-equipped 737's and some time ago at our first MAX.
During maintenance, we often have to check the winglets, and pride ourselves in being the very first MRO in Poland to perform after-market winglet installation, which required heavy modifications in the wing itself. We are very happy, that our customers saved Millions of Dollars annually.
To give credit to other reputable manufacturers, similar technology was used in wide-body Airbuses, and split winglet was first seen on McDonnell Douglas (now Boeing) MD-11 aircraft.
Some of the newly designed wings can withstand great stress, so the winglet doesn't have to be vertical. The 777, 787 or A350 use raked winglet that is blended into the wing itself. It gets the job done, and looks very very cool.
Sometimes you can see planes that don't have winglets, despite being fairly new. Some of the business jets simply don't need them. These airplanes often have laminar flow wing, that is so efficient, induced drag doesn't affect them as much.
Some of the solutions are currently being tested in commercial aviation. An A330 with a laminar flow wing is currently being tested by Airbus. The European manufacturer calls the technology BLADE. We had a privilege to see this last year at ILA Berlin, where LINETECH promoted our base and line maintenance.