maybe i should of rephrased the question

if the treadmill was limited to takeoff speed

seeing as its pretty much improbably that we could get one to go 20 times the speed of sound like you are implying, and even at that speed, it would be the failure of the wheels and not the friction that would limit the takeoff of the aircraft

negating mechanical failure, there is nothing that the treadmill could to to prevent the airplane to take off.

ir force of friction is just too small. you are forgetting another force in this equation, and that is momentum. agreed that larger planes have more momentum than smaller ones, thats clear. but generally, once that much mass gets any kind of forward motion, the force of friction is like pissing into the ocean, it is a mute point

If it was limited to takeoff speed then correct most planes can still take off no problem.

But I did say from the beginning a theoretical treadmill that could go any speed that was required :P
That is what I thought you meant by treadmill.

True, but 70miles an hour is only like 110 km/h or so. At 150-180km/h it is a much more pronounced lurch when you go into neutral (or speed limiter kicks in, lol)

yeh realistically the question is irrelevant due to no one makes a tread mill large enough or quick enough to stop the plane taking off,

it cant take off it the treadmill goes a million miles a hour backwards as it dosent generate enough thrust to overcome that and it would just end up going straight into a object like a house or a wall

if the treadmill is only going 10km a hour then you can easily take off,

if they are going the same speed you would just stay constant as the air wouldnt be flowing under any quicker than it just not turning on its engine or the treadmill as you would not be generating thrust going forward provided the friction applied to the wheels was equal to the thrust generated


this relies on having wheels big enough it makes a difference to otherwise the plane would just end up dragging itself forward on its normal wheels due to them being too small as the force of the plane and thrust would be greater than the applied friction from the wheels. if you had a million wheels the friction/backwards motion would stop it going forwards,

planes generate approx 10,000 pounds of thrust so the treadmill would need to generate 10,000 pounds of negative thrust or friction to keep it still or take it backwards



interesting debate tho

are greater speeds greater air resistance so that makes sense it would also mean a greater deacceleration as u would have more to lose speed wise

lol
comming from a aero engineer, i dont know what plane you are talking about. because it varies quite alot

a 747 has 4 engines, that create about 48,000 pounds of thrust apiece. thats close to 200,000 lbs of thrust

even a G5 has 2 engines that create about 15K pounds each

It it was an example as I didnt know how much they did so thank u I do now know but my point was more about the scenario rather than the fact I dint know how much thrust was generated by a aeroplane feel free to disprove that and I will have no complaints

It it was an example as I didnt know how much they did so thank u I do now know but my point was more about the scenario rather than the fact I dint know how much thrust was generated by a aeroplane feel free to disprove that and I will have no complaints

I think Diz is onto something.

a governor, or speed limiter is different, thats not putting your car or truck into neutral thats a plate forcing your car to decelerate.

there is no "lurch" when going into netural, unless you are doing something wrong

netural disengages everything, and the car is working on momentum alone, since the loss of momentum is a smoth curve, i dont know where this lurch you speak of comes from, unless something is seriously wrong with your car, or you are thinking of downshifting and not going into netural

....

I suppose it would depend on your friction

Imagine it this way.

You have a jet engine; it is suspended by a rope in a pendulum configuration. You turn on the engine. It moves forward and up.


Now you add wheels to the jet engine, and let them touch the ground, while still leaving it suspended from the pendulum. It rolls forward and follows the rope up.


Now you let the wheels touch the treadmill. So long as the treadmill is not applying any backwards force to the engine (which, if it has zero friction, it won't) then once again it rolls forward and moves up.


Then if you remove the rope, it should behave identically other than not following the trajectory of the rope.


Now if the wheels are not frictionless, then you have to define the amount of friction they have, and break out the calculations

A plane sized super fast treadmill is more likely to exist then a frictionless wheel!

apparently nasa says its possible for radio waves to get trapped in the atmosphere and not be heard for years. im hopin for orson wells to be played and panick people again

and the award for the most random and worthless comment of the thread goes tooooooooooooooooooooooooooooooooo

KEMO! COME ON DOWN!

Maybe they will get deflected off of mars then come back to us?