I didn't say move forward at 10mph. I said wheels turn at 10mph. Since the wheels are moving forward as fast as the treadmill is moving backwards, they cancel each other out and there is no forward motion. No forward motion = no overall ground speed, no lift, no flight.

Maybe you guys should actually read my post instead of just jumping on the "oh, you're wrong" bandwagon.

BTW, friction is what keeps the tires on your S from just spinning every time you go somewhere.

 

Explain how those two forces "cancel out". The thrust of the plane will provide forward motion regardless of treadmill speed because the engines on a plane do not use the treadmill IN ANY WAY to provide the forward motion.

A man on Youtube even got his 5 year old kid to understand this. I don't see how you are still not getting it. On top of that, you're being so arrogant about it.

 

this plane won't be moving 1mph ground speed though, it would be moving 11mph ground speed even though the treadmill is spinning 10mph or Xmph for that matter. i just really can't believe that you are missing that. hell its been proven.

 

If you give enough engine thrust to move the wheels forward at 10mph as you say, THE ENTIRE PLANE WILL MOVE FORWARD AT 10MPH NO MATTER WHAT THE WHEELS ARE DOING. Get the plane moving at 10mph on a stationary treadmill, then turn the treadmill on to 50mph backwards, and the plane will continue at 10mph as if the treadmill wasn't ever there.

 

I'm about ready to move this onto the treadmill of the corner...

 

You still don't understand how a plane works. WHEN A PLANE STANDS STILL, WITH ENGINES ON, LIFT IS GENERATED!

 

Check Bernoulli's principle. There has to be air movement over the wings. Engine's pull/push the aircraft through the air to provide that air movement over the wings. Otherwise, why would there be runways?



If the treadmill is rotating -------> at 10mph

and the wheels of the airplane are rotating <------ at 10mph

The airplane remains stationary (ground speed 0mph), so, no lift is created.


If the treadmill is rotating -------> at 10mph

and the wheels of the airplane are rotating <---------- at 11mph

The airplane moves <--- at 1mph. If that is fast enough for the wings to produce enough lift (using Bernoulli's principle) to overcome the weight of the aircraft, it will take off.


Look at it this way. If you put an RC car on the treadmill and turned it on, the car would fall off the back end of the treadmill, right? If you use the remote for the car to accelerate to match it's wheel speed with the backward speed of the treadmill, it would remain stationary (this is what you do when you are running on a treadmill, otherwise you'd just run right off of it, right?). If you accelerate the car so it's wheel speed is faster than the backwards speed of the treadmill, it will drive off the front of the treadmill (which is where an airplane would make lift - forward movement).

I did not say it would not take off, I said that it would have to simply have enough thrust to move forward fast enough, but the forward movement is what is key.

 

The engines are moving air over the wings. When a propeller is spinning, it is pushing air over the wings, regardless of the planes motion.

 

True, but not enough lift is produced to take-off, again, why else would there be runways?

 

It is a function of air speed over the wings. Ground speed is theoretically irrelevant. Obviously a plane with a prop or props that are forward of the wings generates SOME lift. Is it enough to allow the aircraft to take off? Typically it is not but it it at least theoretically possible. A jet aircraft creates no lift at all in this way.

In either case it is strictly a function of air speed over the wings. Ground speed is not a factor. For example, say a plane needs 80 knots of air speed to lift off. If it attains a ground speed of 30 knots into a 50 knot head wind, it will lift off. The thrust generation of the aircraft whether it is a jet or prop plane works against the air, not the ground.