eli5 why are flaps extended during takeoff if they slow down the plane?
In: Engineering
They make the wings bigger so they push the plane upwards harder.
Try this: Get a friend or family member to drive you, and open the window. Use a couple regular pieces of paper, but cut on in half cross-wise so it’s 8.5×6.5 inches. Glue each one to some cardboard. Then go drive around somewhere safe holding one of those out the window tilted slightly up. Then do it at the same speed with the other one. You’ll notice that the air pushes up harder against the bigger piece. It also pushes back, against the direction the car is going. The more you tilt, or the bigger the piece, the harder it pushes up and back.
What flaps do is make the wing bigger, so it pushes up harder. That also means it pushes back more, too. In fact, if you go too fast then you aren’t allowed to use the flaps at all because they’ll break from how hard the air pushes them back.
That’s why we use flaps just at takeoff and landing. We want to be going ever slower to land, so we don’t have to roll so far to stop once we’re on the ground. So flaps help with that. And on takeoff we start from 0, so we use flaps until we’re in the air and going pretty fast. Then we pull in the flaps so the air doesn’t push back so hard, and we can go even faster.
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