plane on a conveyor belt?

[eskimo2]

I think that the “It won’t move or fly” believers have either chimed out or now get it…  

We seem to have some other discussions going on now.  

Those folks who are discussing the catapult and treadmill runway need to clarify if the catapult is attached to the moving belt of the treadmill runway, or if it is affixed to the earth.  I see people interpreting that one at least two ways.

[Kurt]

Originally posted by eskimo2
I think that the “It won’t move or fly” believers have either chimed out or now get it…  

Except for APDrone... He is their evil commander...  chop off the head and the body will die.

[sluggish]

As long as everyone realizes that I was the first one with the correct answer and therefore I won, we can let this thread die a peaceful death with minimal bruising to anyones ego.

[Kurt]

Originally posted by APDrone
If you try to push more thrust than the wheels can keep up, you get to where the plane is going faster than the landing gear, and then this happens:



If the wheels cannot spin fast enough to stay under the center of gravity, the plane will attempt to leave the wheels behind.  Remember, if this happens before you have attained stall speed, you have wreckage.

And suppose its not a tail dragger APDrone... Suppose its got tricycle gear like pretty much everything does these days.    Its certainly not going to nose over like that.

[eagl]

I think that makes sandman the loser, for immediately posting the wrong answer.

Drone gets the loser cheerleader award for trying to disprove Newton in support of sandman's answer

[FBplmmr]

Originally posted by Kurt
And suppose its not a tail dragger APDrone... Suppose its got tricycle gear like pretty much everything does these days.    Its certainly not going to nose over like that.

then it slows down the rotation of the earth!

[eskimo2]

Drone,

Imagine that you are at the gym.  You put roller blades on and get on a treadmill, grab onto the handles and turn it on.  Can you pull yourself forward?

Even if it was a super duper treadmill going super duper fast, do you think that you would not be able to pull yourself forward?

[icemaw]

everybody know once you reach 88mph the flux capacitor kicks in and you get transported back to the future.

[sluggish]

Originally posted by icemaw
everybody know once you reach 88mph the flux capacitor kicks in and you get transported back to the future.

That's not the problem though.  The problem is with generating the 1.21 gigawatts of electricity nessecary to activate the flux capacitor.  I'm sure that in the future plutonium is available at every corner store but right now it's a little hard to come by!

[john9001]

i'm bidding on a flux capacitor on ebay. i may not win, the bidding is going pretty high.

but back on subject, how do seaplanes fly, they have no wheels?

[Sandman]

Originally posted by eagl
I think that makes sandman the loser, for immediately posting the wrong answer.

Drone gets the loser cheerleader award for trying to disprove Newton in support of sandman's answer

Hehe... the cheerleader put way more effort into it.

[hitech]

eagl:

Not much torque in a pure jet. Hi bypass engines have some stators on the housing that produce a fair amount.

As to the original question, it would fly. Rope pulling the airplane is the best example.

Also it would not tip over like the F4 picture no mater how fast you ran the conveyor (Assuming wheels held together).

That is do to the fact rolling friction does not change with speed.
Basicly they are in the form of Force = Weight * Coefficient.  

Where the Weight is the weight on the wheel. And the coefficient is based on the surface, tire deformation, and includes bearing friction. Most comes from just deforming the tire on a hard surface.

[Tuomio]

Actually, the plane would not get up.

If we leave the wheel friction out of the equation, the belt speed will reach infinity if the groundspeed (which is measured from the ground around the conveyor belt) differs from zero (ground speed will be the same with airspeed until it reaches minimun takeoff speed of given plane). This means, that the equation is useless without friction.

With friction, well the airspeed will be zero because the belt will input enough friction in the tire contact to negate thrust from engines. Yes, the tires would spin at outrageous speeds but the plane would be standing still, engines full forward.

Edit: Its important to understand, that the tires are connected to the airplane and they can and will affect the forward pointing newtons. Even without the conveyor belt; as in real life.

[APDrone]

Since Kurt renegged on his finality, I, too, shall take a final final parting shot.

Originally posted by rabbidrabbit
...Even if it was a super duper treadmill going super duper fast, do you think that you would not be able to pull yourself forward?

I requote the original post:

Originally posted by rabbidrabbit
A plane is standing on a runway that can move like a giant conveyor belt. The plane applies full forward power and attempts to take off. This conveyor has a control system that tracks the plane's wheel speed and tunes the speed of the conveyor to be exactly the same but in the opposite direction, similar to a treadmill.
The question is:

Will the plane take off or not?

No mention about allowing or disallowing differentiations in rapid acceleration.. wheel speed will be matched.. period.  

By that definition, a wheel can NEVER roll out of the matching mechanism and can NEVER move forward.  

That is the basis of my entire argument.  I'm not arguing if the physics are in place that would allow such a device to exist. That is not the question placed.  The question is that if the rotation of the wheels have no ability to move the aircraft forward in relation to the rest of the world that isn't on this treadmill thingy or whatever it turns out to be, can the plane attain enough airspeed to take off.  No winches, no catapults, no fingers, no paper.. Airplane, its engine, its gear.  

My answer is still 'No' based on these assumptions of the argument.

And with the previously mentioned caveats ( which seems like an eternity ago ) that there is no significant head-wind and the  aircraft in question does not have the inherent capability of creating enough lift with its engine to launch without a runway.  I'm thinking in terms of the F16, which I understand to have a thrust to weight ratio greater than 1:1, so, theoretically, it should be able to launch straight up. At least that's what they told us 20+ years ago..

I don't 'do' jets.  My observations are based on propeller driven craft.
 
Ok. I'm really done this time.

[Golfer]

The plane flys.  It can be a C-172 and it will fly.  It can be a Citation and it will fly.  It can be an F-15 and it will fly.