Why can headwind assist planes when taking off and landing? Why does tailwind not help with takeoff?
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Planes generate an upwards force using to effects. One is the Bernoulli effect where the faster moving air abow the wing creates a pressure difference which provides an upwards force on the wings. The other effects is air resistance by flying into the air at an angle the air will push the plane up. Its like sticking your hand out from the car window, if its at a 45-ish° angle to the oncoming wind your hand will try to rise.
Now planes when taking off will use a lot of that second effect but they need to get into the air first. Thats where the Bernoulli effect comes in. Now hom much lift comes from that is a function of the velocity of air moving over the wings. Since all kinds of lift comes from the relative air speed for a plane it isn’t the velocity relative to the ground thats important its their air speed. If there is headwind that increases air speed. So the plane has to accelerate less to take off.
Same for landing. The safest landing is a landing preformed with high air speed and low ground speed. You want to have a low velocity relative to the ground so you can stop before you reach the end of the runway. But if the air speed is too low you will stall, an fall. Head wind keeps air speed high to allow the plane to approach much slower.
The way to think about this is that a plane uses fast moving air to stay in the sky but from the perspective of the plane it doesn’t matter whether its the plane moving fast through still air or the wind is blowing fast across the stationary plane. The plane will have lift either way.
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