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Plane on a Conveyor - IT TOOK OFF!

Discussion in 'General' started by will., 13 Dec 2007.

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Will the plane fly

  1. Yay

    89 vote(s)
    72.4%
  2. Nay

    34 vote(s)
    27.6%
  1. chrisb2e9

    chrisb2e9 Dont do that...

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    because a wheel is a mechanical moving part it creates friction when it rotates. Some people think that the friction generated is enough to keep the plane from accelerating to a point where it has enough airspeed to generate enough lift to get airborne.

    Some people are also interpereting the question wrong. they think that the speed of the belt is linked to the rotatinal speed of the wheel, and that the belt and the wheel will keep increasing in speed and never stop increasing in speed. because the wheel is, in this scenario, going extremly fast, they think that there is again, enough friction to keep the plane from accelerating.

    Of course that interpretation is wrong, the speed of the belt is linked to the speed of the airplane. This will cause the wheels to rotate at double their normal speed, which can easily be proven with math.(but I wont get into it because its already been proven in this thread) However even with the increased speed of the wheel, the friction is still not enough to keep the plane from taking off.
     
  2. Smilodon

    Smilodon The Antagonist

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    OK, so this now 13 pages long thread is this long just because someone didn't bother to understand the original problem/question?

    Why am I not surprised? :duh:
     
  3. Oclocker

    Oclocker What's a Dremel?

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    ice cubes are only valid in a scenario such as mythbusters (ie they changed rules so they could claim "myth busted" - but all they proved is they cannot read !) Whilst its possible plane in original scenario would fly, I still think its uncertain & quoting anything outwith the original scenario is invalid. Until its a proven fact its not science!
     
  4. Smilodon

    Smilodon The Antagonist

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    What makes you so sure that you are right, and they (we) are wrong?

    I mean, who decided on the definition here?
     
  5. chrisb2e9

    chrisb2e9 Dont do that...

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    double post
     
  6. chrisb2e9

    chrisb2e9 Dont do that...

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    Thats a fair question. Does anyone know where we can find the original question so we can see if it is open to interprentation?

    1. of course not. unless the chain was a few thousand feet long and the plane was able to get enough speed to take off before the chain pulled tight. and then assuming a tight enough chain, it would crash soon after.

    2. yes, the belt may move some water directly above it, but not enough to have an effect on you.

    3. I think it would crash first. planes aren't the most stable things on the ground. and an avalanche isn't exactly a stable platform to take off from.
     
  7. mvagusta

    mvagusta Did a skid that went for two weeks.

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    Actually chris, a plane can hover when chained to the ground - it can't fly away unless the chain breaks, but if the plane is one that can create enough windspeed through/around the wings, it will hover!


    If the mythbusters re-revisit this myth, and this time use a drag car to pull that conveyor as fast as possible, the plane still takes off, we would still get people saying: "no, it only worked cos it was a small light plane..." :wallbash:
     
  8. Oclocker

    Oclocker What's a Dremel?

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    tbh i'm not sure. but i have googled and looked up some of the older refs to this "scenario" And whilst they vary a lot none "re-invent the wheel" like mythbusters did. What really bugs me is people saying "anyone not agreeing is an eejit, yet they 'prove' their case applying science that isn't in original scenario. The fact that there are so many versions of this myth means that even if its set up as a real life test, then not everyones gonna accept the result. the response time of belt to wheels may be blamed by some for test result failing to match the result they expected. Its a hypothetical scenario - and everyones entitled to an opinion as it is impossible to prove either way imho!
     
  9. mvagusta

    mvagusta Did a skid that went for two weeks.

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    LMAO!!! that's excellent!!! Who cares about what the facts are, or what we see others proove, we are all still entitled to our own opinion!!!

    That's Cheesecake :rock:
     
  10. Smilodon

    Smilodon The Antagonist

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    Actually, I doubt that there are many planes that could do that. For that to happen the engine (most likely a propeller) have to push enough air over the wings. Larger planes often have the engines under the wings, or in the nose of the plane. neither of them will provide much lift by itself. Another scenario is that the force of the engine itself is able to push the plane at an angle. In the latter scenario we are talking about powerful jet fighters.

    Exactly. I'm starting to believe that figuring out who's right in this case will be like trying to figure out which religion is the better one. So this really isn't a discussion about whether the plane will fly or not, it's about what the myth is really about.
     
  11. willyolio

    willyolio What's a Dremel?

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    there's really only 2 interpretations that i can see:

    1. the conveyor belt is moving at the same speed as takeoff speed. mythbusters already proved that one.

    2. the conveyor belt is moving at whatever speed necessary to stop the plane from moving (presumably so fast that the wheels and bearings melt or something). if that were the case, why not just chain the damn plane to the ground? the answer's obvious here. the only plane i know of that can take off in that scenario is the Harrier.
     
  12. Oclocker

    Oclocker What's a Dremel?

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    yes - in the same way some religious people believe in intelligent design and try to bend science to suit..
    But the point is that no ones proved anything anywhere on this senario, and until then yes your entitled to believe plane will fly off and/or world is flat ( its possible the world s flat scenario has been disproved ? )

    As for the original meme - i am sure i recall it from a LONG time in distant past - maybe as mentioned below usenet..

    http://waxy.org/archive/2008/02/06/origins_.shtml
     
  13. mvagusta

    mvagusta Did a skid that went for two weeks.

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    There are some planes that can hover a little under full power if you chain them to the ground, and there are many that will hover while chained to the ground with the engines turned off, when the wind is blowing fast enough.

    Note, both scenarios i've described here assume things like a little slack in the chains, no loads such as cargo, ammo, people, fuel etc in the plane, except for a pilot & a little fuel for my first example, and no avalanches either!

    edit: what? the world is flat? :hehe: :confused:
     
  14. chrisb2e9

    chrisb2e9 Dont do that...

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    and an example of one would be?
    and don't say something like a harrier because that's a different ballgame. there the thrust being produced is greater than the weight of the plane and the thrust is pointed straight down, in opposition to the weight so it is able to take off vertically.

    lets see an example of an actual plane where the prop wash is strong enough that it can cause the plane to actually lift off the ground without it moving.

    again, name one.
     
  15. Jipa

    Jipa Avoiding the "I guess.." since 2004

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    Oh god, drop it already! I don't see any issues involved with the test in MB. Some may always argue, but some also believe in god and ghosts. Anyway I'd claim that a plane on a conveyor belt TAKES OFF until otherwise proven. Not the other way around!
     
  16. Oclocker

    Oclocker What's a Dremel?

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    So your religious then? ie no proof needed that plane will fly? just your claim ? Sounds like mormonism ?
     
  17. Tomm

    Tomm I also ride trials :¬)

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    Yes, I am thinking exactly that. I think we are talking at crossed purposes. For the original scenario (conveyor speed = plane speed), the plane takes off. That's simple (and obvious). But you were talking about a different scenario whereby the conveyor speed is matched to the rotational speed of the wheels - that's what I was talking about. I know the plane's wheels will spin freely etc, but the speed of the wheels is NOT entirely independent of the speed of the plane. In fact they are intrinsically linked.

    This is the formula I gave before:

    s = w - c

    where
    s = speed of plane, through the air
    w = rotating speed of plane's wheels
    c = speed of conveyor belt

    Assuming the wheels don't skid or spin, this formula holds true regardless of whether the wheels power the plane.

    But perhaps it is more logical to rearrange this to:

    w = s + c

    (I.e. wheel speed = plane speed + conveyor speed)

    If w = c, s must necessarily be zero - which is what mvagusta was saying.
     
  18. supermonkey

    supermonkey Deal with it

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    :hehe:
    I think this thread just got GODwined. Is there really any point to dragging this debate on any further?

    -monkey
     
  19. mvagusta

    mvagusta Did a skid that went for two weeks.

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    I'd have to do a fair bit of googling to get some names of planes that can do it, but basically, they have strong prop motors, and with no payload, are relatively light - mainly cargo & bombers - oh, and at least some headwind is required!

    No-one heard of empty cargo planes lifting/hovering with the motors off, just a huge amount of wind?

    And the amount of hover i'm talking about here, can be as little as a few cm, but that's still a hover!
     
  20. willyolio

    willyolio What's a Dremel?

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    technically any plane can hover then, as long as airspeed and windspeed are exactly the same magnitude in opposite directions. some ultralights, or gliders, might be able to do it at very low (i.e. less than hurricane) winds.
     

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