You never used to see it, but nowadays every aircraft has a kink at the end of its wings. What is it for?
The kink is there for a reason and has a name. This is a winglet. The winglet improves the performance of the aircraft, or rather, the wings. It allows you to fly more economically.
How it works exactly is a rather technical story. An aeroplane builds up lift with its wings, read more about this in our theory booklet. The air pressure at the top of the wings is lower than at the bottom. This way, the aeroplane is as it were sucked into the air and hangs on its wings. Pilots therefore sometimes say: "we are going to hang for a while".
Leaky hoover hose
Have you ever tried to clean the floor with a leaking hoover hose? That doesn't work at all of course, because false air is sucked in through the hole in the hose. You lose suction power.
The same happens with wings without winglets. Air flows from an area with high pressure to an area with lower pressure. So air is sucked from the bottom of the wing to the top. This does not provide any lift:
In green (with the minuses) you see the area where the air pressure is relatively lower. And in red (with the pluses) where the air pressure is somewhat higher. These areas run into each other.
By making the end of the wing (almost) vertical, aeronautical engineers ensure that air cannot be sucked from the bottom to the top of the wing so easily:
As a result, less lift is lost. And that in turn means that an aeroplane gets more lift out of every litre of fuel it burns. In short, you get further on a full tank.
The result? You can save up to 4% in fuel consumption!
Is that all?
Not quite, the winglet also reduces the turbulence behind the aircraft. This makes it safer for traffic coming up behind.