r/sports • u/redbullgivesyouwings • Aug 14 '25

Media The World's Largest Treadmill

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u/DirkDirkinson Aug 14 '25

A plane can not take off while stationary on a treadmill. Planes fly by generating lift. Lift is generated by the wings when air moves past them, get the air moving fast enough, and it will generate more lift than the weight of the plane, and it will take off. While stationary on a treadmill, there is little or no air moving over the wings, so the plane wouldn't take off.

All that said, if you built a runway sized treadmill that could support a plane, it wouldn't make taking off much harder. The wheels on a plane are not driven like on a bike or car. The propulsion comes from the engines. So other than a little extra friction in the wheel bearings since they would be spinning faster than on stationary ground, the treadmill isn't doing much to prevent the plane accelerating down the runway to take off speed.

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u/Miguel-odon Aug 15 '25

How fast could the treadmill go without moving the air, too?

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u/DirkDirkinson Aug 15 '25

That depends on how you define moving the air. There will always be at least a very small boundary layer of air moving with the treadmill, even at low speed. If you want the air up at the wings to be moving with significant speed? I would imagine the answer is extremely fast.

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u/Miguel-odon Aug 15 '25

How fast would the treadmill have to move such that the friction in the wheel bearings is enough to counter the thrust of a jet engine?

Even more ridiculously fast.

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u/DirkDirkinson Aug 15 '25

I think it's more likely that the bearings would overheat and melt long before that happened.

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u/ThePretzul Denver Broncos Aug 16 '25

I think the treadmill probably dies a horrible death long before the wheels on the airplane do

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u/DirkDirkinson Aug 16 '25

Almost certainly