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Post by Orbs on Jul 15, 2009 21:37:47 GMT
Could it land on a treadmill? ![;)](//storage.proboards.com/800541/images/0m0lbCuTEBzaRn6f8QaM.gif) Yes, but it will still travel the same distance down the runway as if it wasn't there. S'cuse me?
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Post by rocket88 on Jul 15, 2009 21:38:05 GMT
I know this has been on the internet for a while, but haven't seen it on the oatie, and thought it would make a change to the conspiracy theories and how wank britain is.A plane is standing on a runway that is made of a large conveyor belt. The plane fires up its engines, but as it moves forward, the conveyor belt senses the speed of the plane's forward motion and instantaneously moves at exactly the same speed in the opposite direction. Can the plane take off? NO, of course it cant. Now shut up you thick (maybe piss taking ![;)](//storage.proboards.com/800541/images/0m0lbCuTEBzaRn6f8QaM.gif) twat ? Discuss. I say yes.
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Post by edinburghstokie on Jul 15, 2009 21:48:16 GMT
now then rocket, no need for name calling, particularly if you are wrong.
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Post by bondygodfatherleek on Jul 15, 2009 22:11:40 GMT
now then rocket, no need for name calling, particularly if you are wrong. Stoke_ed, you know I'm the last one to cause trouble. But the Baggage Handlers Union have asked me to have a quite word with you lot. Is the plane going to fly or not??? ![;)](//storage.proboards.com/800541/images/0m0lbCuTEBzaRn6f8QaM.gif) 8-)Bondy ![](http://blog.nj.com/ledgerupdates_impact/2008/07/large_Baggage.jpg)
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Post by rocket88 on Jul 15, 2009 22:34:45 GMT
now then rocket, no need for name calling, particularly if you are wrong. I put a smiley in there , you daft cunt!!! ![;)](//storage.proboards.com/800541/images/0m0lbCuTEBzaRn6f8QaM.gif) ;D I am sure that you have posted this thread as a piss-take, as you seriously cannot be serious ??? It's so obvious that it does not deserve a serious answer!!!! ;D
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Post by bondygodfatherleek on Jul 15, 2009 22:42:28 GMT
now then rocket, no need for name calling, particularly if you are wrong. I put a smiley in there , you daft cunt!!! ![;)](//storage.proboards.com/800541/images/0m0lbCuTEBzaRn6f8QaM.gif) ;D I am sure that you have posted this thread as a piss-take, as you seriously cannot be serious ??? It's so obvious that it does not deserve a serious answer!!!! ;D Rockett, stop your swearing. ![:-[](//storage.proboards.com/800541/images/fwGSRilBFZwfei5Q6XIp.gif) Now have you got a valid driving licence. if so meet me at the Airport at 4 am sharp and bring your goggles. We'll have to start moving the back log of planes, there's a couple of air stewards in it for you. ![:o](//storage.proboards.com/800541/images/7TTgAtwUz19SBi0cvrCX.gif) ;D ;D 8-)Bondy ![8-)](//storage.proboards.com/800541/images/ibnJJzaA6ZhfTOIekEAf.gif) Make sure you take your blood pressure pills this time ![::)](//storage.proboards.com/800541/images/cj7bsBj2jOTuEAUVaPt5.gif)
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Post by edinburghstokie on Jul 19, 2009 21:12:49 GMT
Dave, have you asked you aeronautical engineering friend yet?
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Post by jonesinamillion on Jul 19, 2009 23:13:05 GMT
My mother is writing into theNew Scientist Magazine fr a definitive answer, i'll let you know the answer (I'm still going with yes!).
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Post by edinburghstokie on Jul 20, 2009 6:39:13 GMT
Just seen this analogy and think it might really help some people here.
If you are running with a kite at 5 mph, into a wind that is 5 mph, the kite lifts off… Isn’t that essentially the same thing?
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Post by beagriestache on Jul 20, 2009 8:02:05 GMT
Depends on what the air speed over and under the kite surface is, as this is ultimately what produces lift. I suspect with a kite the angle of attack of the kite means the airspeed differential over its surface is a lot greater than your simple equation would indicate.
I accept your theory about the thrust of the engine being in the air etc, however I still don't think a large heavy aeroplane would take off on a treadmill as the downward force due to gravity on the free-spinning wheels is significant.
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Post by edinburghstokie on Jul 20, 2009 11:51:49 GMT
Ah but the force is directly down, and the thrust is exactly 90° to that. The component of a force at 90° to it is always zero. Therefore gravity will not affect the forward motion.
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Post by beagriestache on Jul 20, 2009 12:01:43 GMT
That's true but gravity and therefore the weight of the plane (which is obviously a function of gravity) will have a significant effect at this scale in terms of friction and therefore drag. It's a big assumption that the wheels turn frictionlessly at this scale.
And if they don't as a result of down force on the wheels, bearings whatever, then the treadmill can exert drag on the plane and at great enough speeds render it effectively stationary.
So your theoretical plane may take off. But can a plane take off on a treadmill? No.
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Post by mermaidsal on Jul 20, 2009 12:30:45 GMT
Has this damn plane still not taken off, hasn't ANYONE spent the weekend making a treadmill and a plane to try it?? Lightweights ;D
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Post by thepremierbanksy on Jul 20, 2009 13:41:50 GMT
Just seen this analogy and think it might really help some people here. If you are running with a kite at 5 mph, into a wind that is 5 mph, the kite lifts off… Isn’t that essentially the same thing? Nope. Like all the answers to your original question, the important thing is the wind speed in relation to the wings. In the example of your kite the fact you are running into the wind is additive and so the airspeed speed = 10 mph. You could achieve the same by airspeed by standing still in a 10mph wind or by running at 10mhp in no wind. Your plane on the treadmill is subtractive, the two forces cancel eachother out so that the plane is not moving, therefore airspeed is 0mph (assuming the absence of wind). As for landing on a treadmill, yes that could be done but only assuming the wheels have friction (obv you will want to brake). With frictionless wheels though you could possibly swoop and land on a treadmill with the engines still going and zip along it like it wasn't there. To land on a treadmill properly would be very dangerous as you would need to land dead-straight.
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Post by Irish Stokie on Jul 20, 2009 16:12:34 GMT
My Dad is an aeronautical engineer so to put this to bed, no a plane cannot take off on a treadmill
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Post by beagriestache on Jul 20, 2009 16:17:39 GMT
Yay, I win!
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Post by french toast on Jul 20, 2009 17:08:03 GMT
my dad isnt one of them but he says it will so, the thread is reopened
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Post by neoisd1 on Jul 20, 2009 17:49:40 GMT
Can't believe this is still on going! THE PLANE WILL TAKE OFF! And for all of you who say it won't please just answer me this simple question then!
"By what mechanism does the conveyor belt restrain the plane from moving forward?"
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myatt
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Posts: 194
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Post by myatt on Jul 20, 2009 20:27:38 GMT
Having only just seen this, I think you are all missing the point! Its obviously an impossible situation, to which there is no answer.
The plane has to take off becuase the engines act on the air and there is no force to stop it moving forward.
It cannot take off due to the fact that it won't move forward due to the treadmill.
Both reasons are 100% vaild. It does make you think though!
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Post by thepremierbanksy on Jul 20, 2009 20:54:31 GMT
Having only just seen this, I think you are all missing the point! Its obviously an impossible situation, to which there is no answer. The plane has to take off becuase the engines act on the air and there is no force to stop it moving forward. It cannot take off due to the fact that it won't move forward due to the treadmill. Both reasons are 100% vaild. It does make you think though! The engines are on and displace air, but that air does not pass under the wings are create uplift. The plane will not take off, nor is it an impossible situation.
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Post by rocket88 on Jul 20, 2009 21:52:12 GMT
If the plane is not physically moving forward there is no air pressure created under the wings (& lower pressure above the wings). Think about it ????? Why the hell would companies spend millions creating & maintaining runways if they weren't needed ?
Bangs head against wall & begins to sob uncontrollably.........
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Post by march4 on Jul 20, 2009 22:00:23 GMT
If the plane is not physically moving forward there is no air pressure created under the wings (& lower pressure above the wings). Think about it ????? Why the hell would companies spend millions creating & maintaining runways if they weren't needed ? Bangs head against wall & begins to sob uncontrollably......... That must be the final and convincing answer. If planes could take off from conveyor belts wouldn't aircraft carriers be covered in them to get the planes into the air? And why do our airports have all of those runways if they are only needed for landing? I am tempted to mock this up with a model to prove the point, but I'm too preoccupied at the moment thinking of a use for Vincent Pericard (sorry wrong board).
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Post by edinburghstokie on Jul 21, 2009 6:19:54 GMT
Planes can take off on conveyor belts, however the conveyor belt has no effect on the take off (might counteract it a little at the start). Therefore the runway is still the same length. The plane still has to build up air speed which it can only do by moving forward (what the engines do).
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Post by wembley4372 on Jul 21, 2009 7:09:46 GMT
We should convert this technology to make the motorways conveyer belts, much better to waz along a 180mph not having to worry about driving.
Might be a bit dodgy coming off the M6 at junction 15 with that bend though!
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Post by rocket88 on Jul 21, 2009 11:16:52 GMT
Planes can take off on conveyor belts, however the conveyor belt has no effect on the take off (might counteract it a little at the start). Therefore the runway is still the same length. The plane still has to build up air speed which it can only do by moving forward (what the engines do). Answer me this; If I stood on the ground next to the plane/treadmill, would the plane be moving forwards in relation to my stationary position ? If you answer YES, please explain how it's capable of moving forward (in relation to a stationary object), when it's on a treadmill which cancels out any forward movement. If you answer NO, please explain how airspeed is attained to gain lift. All this question boils down to is, "is the plane travelling forwards in relation to a stationary object" ?
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Post by es on Jul 21, 2009 11:41:44 GMT
Planes can take off on conveyor belts, however the conveyor belt has no effect on the take off (might counteract it a little at the start). Therefore the runway is still the same length. The plane still has to build up air speed which it can only do by moving forward (what the engines do). If you answer YES, please explain how it's capable of moving forward (in relation to a stationary object), when it's on a treadmill which cancels out any forward movement. [/b][/quote] fuck sake. when the plane moves forward (with jets) the wheels (free turning) will move faster...
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Post by neoisd1 on Jul 21, 2009 11:56:52 GMT
Planes can take off on conveyor belts, however the conveyor belt has no effect on the take off (might counteract it a little at the start). Therefore the runway is still the same length. The plane still has to build up air speed which it can only do by moving forward (what the engines do). Answer me this; If I stood on the ground next to the plane/treadmill, would the plane be moving forwards in relation to my stationary position ? If you answer YES, please explain how it's capable of moving forward (in relation to a stationary object), when it's on a treadmill which cancels out any forward movement. [/b][/quote] YES YES YES! The whole point is that the TREADMILL CANNOT cancel out any forward movement! In essence the plane will take off the same if its on a treadmill or on a normal runway as the wheels are independent of its engines and therefore will just spin faster as the treadmill moves faster. Why people can't get their head around this is beyond me?!!?
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Post by rocket88 on Jul 21, 2009 12:21:33 GMT
I feel silly now!!! ![:-[](//storage.proboards.com/800541/images/fwGSRilBFZwfei5Q6XIp.gif) I pictured a treadmill that was 'plane sized', not the length of a runway!!! ;D Edit; Please feel free to hurl insults & abuse at me.
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Post by rocket88 on Jul 21, 2009 12:25:14 GMT
I know this has been on the internet for a while, but haven't seen it on the oatie, and thought it would make a change to the conspiracy theories and how wank britain is.A plane is standing on a runway that is made of a large conveyor belt. The plane fires up its engines, but as it moves forward, the conveyor belt senses the speed of the plane's forward motion and instantaneously moves at exactly the same speed in the opposite direction. Can the plane take off? Discuss. I say yes. Just re-read the question & I've changed my mind. No, it can't take off, because of this bit >"but as it moves forward, the conveyor belt senses the speed of the plane's forward motion and instantaneously moves at exactly the same speed in the opposite direction". If the conveyor belt instantaneously cancels out the forward motion, then the plane is in fact at a standstill in relation to the ground. It's got nothing to do with the speed of the wheels, the question states that it's the PLANES forward motion that is detected & compensated for by the belt. The plane is effectively rendered stationary & won't take off.
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Post by rocket88 on Jul 21, 2009 12:38:27 GMT
If the plane does 100mph & the belt does 100mph in the opposite direction, the wheels will be rotating as if they were doing 200mph, but the planes going nowhere.
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