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

In modern aviation, the wings are designed optimally for (fuel) efficient flight at high speeds and high altitudes – since that’s where they spend the vast majority of the flight. So, they tend to have a thin cross-section and be long and ‘narrow’, and that generates enough lift but relatively little drag.

But the above type of wing would be far from ideal for low-speed take off and landings. So, most aircraft have slats on the leading edge of the wing and flaps on the trailing edge which can be lowered to *effectively* turn the wing into a ‘deeper’ aerofoil shape which generates a lot more lift at low speeds – even if it is more draggy. Requiring a high take-off speed is dangerous, especially in the even of an aborted take-off.