Antz
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I don't think it will take off... I might be confused...
Asuming the tredmill can keep up with the planes speed...
The plane will not take off because the upward force is not being generated... otherwise planes would just sit on the run way and not bother with the long run up before taking off, they'd just use the wind...
The plane only takes that long run up to maximise upward force... on a tredmill there would be no upward force.................................
HELP!
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Antz
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AND ALSO... you ever tried walking on a tredmill set to run speed... you fall off the back... the plane would have to provide thrust in order to keep up with the tredmill and then more the thrust off the thing??????
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Steve
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read the thread you will realise
the planes wheels are not providing the drive like your legs are on a treadmill
[Edited on 25-05-2006 by Steve]
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Antz
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So what you're trying to say is the plane might as well be floating above the belt, as in, the belt drive the wheels thus keeping the plane in 1 spot... then the thrusters used to power it forward?...
It wouldn't work becuase the wheels would not be able to turn that fast with friction, therfor the plane would fall off the back, soooooo you'd have to use maximum thrust and a bit more to take off (the bit more just being used to stop it from falling off the back before it gets max thrust)........ the friction alone caused by the belt would prevent it taking off, or rather prevent maximum speed.
[Edited on 25-05-2006 by Antz]
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Steve
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the friction on the wheels is very very small, go try it using a toy car
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Antz
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ahhhh.... wait.... planes take off from moving boats, so yeah, it would take off, or rather, in the right conditions ie right sized belt and all that it would be possible.
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Antz
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quote:
Originally posted by Steve
the friction on the wheels is very very small, go try it using a toy car
Yeah, but my point was... if you put a toy can on a belt and held it it would be fine, but as soon as you let go it would stop and fall off the back.....
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Steve
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yeah, but the force that is needed to hold it is hardly anything.
scale it up, say the eine are providing 24000lbs of thrusand the friction force acting on the wheels is say 500lbs there is plenty to make it move fast enough
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RichR
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my final say on this:
I do agree that if the wheels spin - there will be forward momentum - I understand that argument and the physics/energy transference therein
My argument relates to wether the wheels would spin
scenario1
You take a model car and place it on a treadmill - the wheels freewheels
now take the car off and turn the treadmill off
place the car on the treadmill but this time put all your physical weight on top of the toy car - acting perpendicular to the treadmill - if enough energy is exerted when you come to turn the treadmill on and increase the speed - the downward pressure/mass and gravity force acting would be enough to prevent the treadmill from moving
its like a belt sander - if you push the wood onto it with too much pressure you stop the sanding belt from moving Yes?
People are assuming that the friction force is negligable but I argue that it isnt; as I said before I fully understand the argument by Steve,John, Ian, Jules etc
but Ian wrote off the mass of the plane as having any effect
my argument is that the mass of the plane and gravitational forces acting will be enough to prevent the wheels from spinning
now we know that a plane winds up its thrust to nearly full thrust at the end of the runway, with its brakes on - these brakes prevent the wheel from spinning and forward momentum of the aircraft; until such a tiem as the thrust is at full throttle and the brakes are released - the brakes can clearly hold back the plane from nearly full thrust - If this wasnt the case planes would drag themselves down the runway as the thrust increased!
if the brakes stop the wheels, then why cant the counter acting motion of the conveyour and the force of mass acting downwards act in the same way - preventing the forward momentum of the plane
As I said I understand the argument as to why the plane would take off but the argument hinges on wether the wheels would spin - remember that the mass distribution and scaling of a toy car to a full size plane is massively different
I'm not going to argue anymore as I understand both points of view - but it would be nice if someone could see where I'm coming from!
and Jules my statement regarding the weight as a function of cosine squared isnt a theory its one of the forward momentum calculations components - it takes account of all forces - your argument was ignoring the physical mass of the plane!
[Edited on 25-05-2006 by LiVe LeE]
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Ally
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Ask Jeeves for gods sake.
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chris_uk
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its quite simple...
there is no wind being generated under and above the planes wings, therefore no lift.. so a plane cannot take off.
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RichR
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chris that isnt the argument - infact it has nothing to do with the argument - if the wheels do spin then there will be forward momentum - the plane will get lift
I'm arguing that the wheels wont spin
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gianluigi
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The plane wil l take off
Only if Chuck Norris roundhouse kicks it from behind which will generate more than enough thrust and lift.
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chris_uk
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quote:
Originally posted by LiVe LeE
chris that isnt the argument - infact it has nothing to do with the argument - if the wheels do spin then there will be forward momentum - the plane will get lift
I'm arguing that the wheels wont spin
if the plane is sat on a conveyor belt.. and starts to go and the plane is somehow magically held there without falling off the wheels will spin..
(imagine a reverse roaling road)
the plane does not use its wheels to gain thrust or momentum.. the wheels on a plane are like he wheels on the back of your car.. they just spin.. the thrust comes from the turbine engines on the wings..
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John
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RichR
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change the one tonne weight of the car to 75-100 tonne+ of a plane - rollers wouldn't roll
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chris_uk
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quote:
Originally posted by LiVe LeE
change the one tonne weight of the car to 75-100 tonne+ of a plane - rollers wouldn't roll
it was an example u pleb..
the wheels on a plane DO NOT produce thrust.. planes use the jet engines to produce thrust.. so if you stuck it on a conveyor belt there would b no wind generated so no takeoff would happen.. IF!! you had 1000's of fans blowing at the plane at about 170 mph, then yes the plane would take off and it would stay stationary.
every seen birds in the sky just seeming to hover in the air?? same principle
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RichR
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jesus christ u muppet - read the full 33 pages on the real thread - dont come in with your half hearted theories - most of which have been dismissed already
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Sam
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Will you all STFU this is BORING now! 
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chris_uk
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quote:
Originally posted by LiVe LeE
jesus christ u muppet - read the full 33 pages on the real thread - dont come in with your half hearted theories - most of which have been dismissed already
the question right from the start was 'will a plae take off if it was on a conveyor belt'
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Antz
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And the answer is yes it will...
Jesus, I thought I was thick but I get it now! 
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3CorsaMeal
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all DIE DIE DIE
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Steve
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OMFG not again
look the answer IS it WILL, people need to stop arguing this fact and start to think why it will
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3CorsaMeal
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i've convinced myself, and thats enough 
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Haimsey
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seven
Marcy Marc 
White Sport Progress Thread
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