will it take off?

Egon · Feb 3, 2008

I know you don't Eric but there was a trick answer. Read again!

Tricks go both ways!

Sooner or later we all die. It matters not what we survived.!

ray66v · Feb 3, 2008

Egon said:
Sooner or later we all die. It matters not what we survived.!

None of us are getting out of this alive.

Egon · Feb 3, 2008

It all depends on the airspeed!

patrick_g · Feb 3, 2008

SPYDERLK said:
With skis I can see at high speed that tremendous energy is dissipated, but I cant see how that can increasingly factor against thrust as conveyor speed rises. How does that work??

Youre right. Its the mind exercise of considering the possibilities that makes this fun. Were doing alot better on this than MythBusters.
larry

Friction is not linear with varying speeds in the case of a ski on ice or snow. The speeding ski warms up which changes the nature of the interface in the interstitial spaces.

Energy or the work done per unit time dragging a ski is a function of coefficient of friction, weight of the loaded ski A-N-D the speed of the ski (as well as various design considerations in the shape of the ski.)

"Force acting through a distance" where the distance is increased per unit time with higher speeds is increased energy dissipated per unit time which can, if made great enough by sufficient velocity of the conveyor, will equal and cancel any finite thrust. This is the frictional analog to the rotational inertia being used to develop a counter force to offset thrust. You don't need rolling friction to counter the thrust, just a conveyor that can accelerate quickly enough.

If you go "real world" on me then I confess the tires will lose traction and be rapidly worn out and overheated to the blow out stage very quickly but then waht has reality to do with any version of the problem not letting the plane take off with wheels spinning at twice the takeoff speed?

An aside for those who think an airplane prop moves along like a lead screw. It doesn't. There is considerable slippage, more so at the start of the takeoff roll.

Thrust is a force measurable in such units as poundals where a poundal (pdl) is the force that will impart the acceleration of one ft per second per second to an object that weighs one pound. Strictly speaking a pound is not a force such as we might use in the equation F=MA.

Pat

patrick_g · Feb 3, 2008

ray66v said:
None of us are getting out of this alive.

What, no possibility even quite remote for rapture?

Pat

Egon · Feb 3, 2008

Seeing that the "Myth Busters" have "Proven" that the conveyor belt is a success we just have to devise a method of pulling a tarp under commercial aircraft!

Now which truck make should we use to pull this tarp??

I've got a Dodge so I'd suggest a Dodge!

Mayhaps I should also try and grow a Mustache!

tallyho8 · Feb 3, 2008

While we're at it, could we determine what happens when an irresistible force meets an immovable object?

Will the immovable object take off?

patrick_g · Feb 4, 2008

Egon, All the Myth Busters proved was that their truck was not up to the task of providing a Magic Conveyor. They used a Dodge, maybe we should consider a GMC or a Ford or a pedicab.

Pat

Egon · Feb 4, 2008

Okay, that leaves a Ford or Chevy or Tundra or ???

turnkey4099 · Feb 4, 2008

patrick_g said:
Friction is not linear with varying speeds in the case of a ski on ice or snow. The speeding ski warms up which changes the nature of the interface in the interstitial spaces.

Energy or the work done per unit time dragging a ski is a function of coefficient of friction, weight of the loaded ski A-N-D the speed of the ski (as well as various design considerations in the shape of the ski.)

<snippage>

Pat

Unless I misunderstood my physics class way back when, the coefficient of friction on a ski goes down as friction warms the ski. Of course there would be an upper limit to that effect.

I posted the original 'skis/ice' bit and, as usual, forgot to add 'takes off as long as thrust overcomes drag'.

I must admit that the long discussion involving infinite speeds, etc. is fog to me. I think too linearly to understand it, I guess. In my view, the max speed of the plane is Take Off, around 70 for a reasonable example, thus the converor's max speed would be 70 retrograde and wheels max would be 140. I can't get my mind wrapped around the reasoning allowing any speeds above that.

Harry K