will it take off?

[SPYDERLK]

NorthwestBlue et al, we only need enuf tire traction to prevent the plane moving with locked brakes. Tire and bearing friction losses can be zero and the plane can still be held still by the magic conveyor if the wheels are not massless. To hold the plane still the conveyor would just push backward on the tire contact patch an amount equal to the thrust of the plane engine. This would, of course, spin up the wheels very quickly to an rpm where they would fly apart. Until this happened tho the planes thrust would be counteracted by the force=MA being applied to spin up/accelerate the wheel mass. The plane would remain still. After the centrepital explosion the plane would be pretty torn up by flying debris and whats left of it would flop down on the conveyor that would be running backward at somewhat less than mach 1. Takeoff would not be an issue at this point.
Larry

 

[HTWT]

What does it imply when it states when the plane moves???? I do not believe it means it is stationary. If it is stationary then the treadmill does not move.

 

[N80]

This would, of course, spin up the wheels very quickly to an rpm where they would fly apart.

I seem to remember some USAF aircraft, maybe the Valkyrie (experimental suspersonic bomber...possibly the most beautiful plane ever) that spun the wheels up prior to landing to decrease the heat and friction of initial contact.

 

[SPYDERLK]

I seem to remember some USAF aircraft, maybe the Valkyrie (experimental suspersonic bomber...possibly the most beautiful plane ever) that spun the wheels up prior to landing to decrease the heat and friction of initial contact.

Yeah, I believe it. Lotsa good reasons probably. A plane like that may have a high landing speed that would exacerbate the backward jolt coming from quick wheel spinup on ground contact. This could cause transient stability problems in addition to the high wear and stresses.
Larry

 

[WVBill]

Get a model airplane (or anything with wheels). Go to the gym.
Stand next to one of the treadmills and hold the model airplane on the treadmill. Have someone else control the treadmill.

Start walking forward while holding the airplane in contact with the treadmill. (You are the airplane's engine pulling it through the air) At the same time, have your helper start the treadmill.
You WILL move the airplane "through the air".

Have your helper keep increasing the speed of the treadmill.
If the treadmill were long enough and you could run fast enough the movement of the air over the wings would create enough lift and the plane will fly.

The surrounding air (with the exception of a very thin boundary layer) is independent of the treadmill/conveyor belt/runway. The airplane's engine/propellor interacts with the surrounding air - not the treadmill/conveyor belt/runway.

You could do this experiment with a flyable model plane too if the gym would let you.

WVBill

 

[SPYDERLK]

WVBill, on the model plane you are the equivalent of millions of horspower on a large plane. You are literally the equivalent of a rocket engine - able to lift the load straight up against gravity and with enuf left over to accelerate the loads mass at several G's. The analogy you give includes so much excess thrust that any retarding force resulting from a real world conveyor accelerating the wheels would be lost in the noise. A magic conveyor however, acting against non massless wheels that could be constantly accelerated [ultimately to infinite rpm] without exploding, would counter any finite thrust and prevent plane motion wrt earth forever.
Larry

 

[MossRoad]

A nice trout sounds better Moss.

Buggiesd are always transpoted in a container requireing them to be in flight. Keeps the weight down you know!

Yes. Getting a rise out of a nice trout is always nice. Maybe that's why they call internet scams fishing?

 

[Piedmont3]

I have been reading this for about a week now.
I have a couple of questions?

Have you ever walked on a treadmill? or maybe even run on a treadmill?...
I have done both as well as running outside on the road.

Did you feel the wind blowing your hair?
Not on the treadmill but yes on the road. The difference is I was moving forward on the road and not moving forward on the treadmill.

I say that the plane will not move if the conveyor and will keep up with the wheels of the plane, regardless of the forces expended or created by the engine.
If the plane does not move forward, then the plane will not take off.

 

[Highbeam]

The plane will move forward, gain airspeed, gain lift, and then fly. To gain forward motion the plane's prop grabs onto the air (the air is not connected to the wheels or the conveyor) to pull the plane and the wheels do nothing to restrain the plane from moving forward. Wheels will move fast but the prop just keeps on grabbing air and making thrust to acelerate the plane.

I think the best example was the early one of a guy with rollerskates on a treadmill pulling on a rope attached to a far wall. The source of force for forward motion is not being created by the wheels of the skates or of the plane.

If there is word trickery such that the plane can not gain groundspeed then of course there will be no lift and no flight.

 

[turnkey4099]

I keep waiting for the naysayers to explain just what happens to the thrust of the engine (either prop or jet). Remember it is acting on the surrounding air which is not interacting with the MCB, i.e., if the air is calm it will remain calm no matter the speed or direction of the MCB. So the prop spins up, develops thrust trying to move the plane _through the air_. How do you who maintain the plane won't move (through the air) explain away the simple physics of the above? You somehow have to get rid of some pretty massive force trying to pull the plane _through the air_.

It is a simple equation where force = thrust. You have force, what are you going to do with the 'thrust'?

Harry K