this post was submitted on 26 Jun 2024
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Science Memes

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Mythbusters (mander.xyz)
submitted 5 months ago by [email protected] to c/[email protected]
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[–] [email protected] 2 points 5 months ago (1 children)

Oh wow thank you. This is genuinely excellent and immensely helpful. I think this bit:

A treadmill will only push an aircraft or whatever else along, with an acceleration that is equal to, or lower, than the rolling resistance. If you try to accelerate the plane faster, it’ll ‘slip’

As well as this video that I found where a pilot explains how under specific but unrealistic conditions you could construct a treadmill that does indeed prevent an aeroplane from taking off,

Really helped solidify my understanding of the problem. So you end up with a situation where the wheels are going to be slipping, just like the slippage created when your hand pushes a toy car on a treadmill.

Thanks!

[–] FuglyDuck 2 points 5 months ago

So, another way to think about it is with Kites.

The air flows around it the same way it would any other kind of aircraft, though they have effectively zero ground speed.

They do differ in that, being tethered, they’re pulled through the air, with the wind providing the energy to stay up.

But they’re still moving through the air, and the airfoils are inducing drag to convert some of that energy into lift.

In both cases, the important speed is relative to the air, not the ground and not the treadmill. The wheels might impart some drag while they’re on the ground, but they’re never going to impart enough to overpower the engines- 747s typically take off at about 75% of their rated take off power, which means a longer take off roll, but less wear and tear.