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Jon Letendre

747 on conveyer

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No. If a person is moving at the same rate as an escalator hes essentially standing still. On the other hand if the person in the same example was wearing a wind suit and there was sufficient air moving over him to provide lift then, yes, he might fly. 

The plane in the example is not provided any lift to overcome gravity. The speed needed to gain loft is nullified by the counter rotating conveyor.

The better question is why does it matter?

https://blog.xkcd.com/2008/09/09/the-goddamn-airplane-on-the-goddamn-treadmill/

Holding my breath for merjets answer. ;)

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Hi Geoff,

The plane sits atop freely-spinning wheels and is pushed forward by jets attached to the wings.

Imagine standing on a skateboard on a moving walkway at the airport.

There is a little bit of friction where wheels meet walkway and in the bearings of the wheels, so you are going along with the walkway just like the people with no skateboard underneath them.

I am on solid floor beside the walkway.

We hold hands and I start to walk in the direction opposite of the walkway.

Will the walkway win this tug-of-war, will it pull you in its direction, or will I win and get you to come in my direction?

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2 hours ago, Jon Letendre said:

747-take-off-conveyor-belt.jpg

Yes. The air moving over the wings will provided life and the engines or propellers will provide forward thrust.  The plane will raise of the ground and go forward in the air.

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Just now, BaalChatzaf said:

Yes. The air moving over the wings will provided life and the engines or propellers will provide forward thrust.  The plane will raise of the ground and go forward in the air.

Just like every other takeoff the plane has ever taken.

only difference is her wheels will be spinning at double the usual rate, and  backwards.

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It is interesting to note, also, that the conveyer can run in either direction at any speed, it can even switch directions while the plane is accelerating for takeoff - with no effect on the plane's forward progress and eventual takeoff.

Edit: I almost forgot Bob is on the forum. There will be a small dent in plane acceleration if the conveyer switches direction during takeoff, due to the rotational inertia of the wheels.

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