eli5 why are flaps extended during takeoff if they slow down the plane?

Question

eli5 why are flaps extended during takeoff if they slow down the plane?

In: Engineering

Answer 1

Some planes need a bit of extra lift to get off the runway and climb at the desired rate, but having the wing be that shape would negatively impact performance in other situations (like in cruise flight). So the plane is designed to have the flaps at a certain setting during takeoff which can then be retracted when that extra lift is not needed.  

Creating lift does create extra drag but it depends on a lot of things like speed, angle of attack, and the shape of the wing.  

Ultimately though to answer OPs question the flaps are lowered on some airplanes during takeoff because the benefits outweigh the cost.