Burble Burble Posted February 6, 2008 Share Posted February 6, 2008 Why use the plane anyway? Turn the teadmill round and step on it. Cheapest flight you'll ever take. Quote Link to comment Share on other sites More sharing options...
AndrewOW Posted February 6, 2008 Share Posted February 6, 2008 No air is passing over and under the wings to give lift (high/low pressures) etc, plus the engines would overheat too I'd thought. EDIT: So no it won't take off. Just ask supradibbs So I was wrong Oh well every day is a learning day. (Its still doesn't seem logical, but still!) I'd like to cue the conveyor belt scene, where they were trying in escape the mincing machine, in Wallace & Gromit, A Close Shave, but I cannot find it easily. Oh well, its the thought that counts Quote Link to comment Share on other sites More sharing options...
spidermonkey Posted February 6, 2008 Share Posted February 6, 2008 People always say that, when they've been proved wrong about this question. The question is worded perfectly, but people jump to the wrong conclusion before thinking it through thoroughly. i think you will see that i have said i was wrong due to some cleverly raised points by some people on here, it is my opinion that the question is not as clear as it could be, again that is my opinion, also i have not seen this evidence that i was proven wrong just a few posts with some clever theories in them that has made me change my opinion, i only stated that if the thrust or moment was counteracted exactly then the plane cannot take off, this is how i misread the question in the 1st place, still this has been a most enjoyable thread so well done to its creator:) Quote Link to comment Share on other sites More sharing options...
Jay_vr6 Posted February 6, 2008 Share Posted February 6, 2008 I can't be bothered to read 11 pages of this but I just saw this on mythbusters Quote Link to comment Share on other sites More sharing options...
spidermonkey Posted February 6, 2008 Share Posted February 6, 2008 I can't be bothered to read 11 pages of this but I just saw this on mythbusters oh you should it has been VERY entertaining, i have realy enjoyed this and i was on the wrong side Quote Link to comment Share on other sites More sharing options...
Matt H Posted February 6, 2008 Share Posted February 6, 2008 I dont know if it was just me but.. It doesnt bother me that people dont understand things or get things wrong, but i have to admit; when people where still arguing the toss after the first post that pointed out that a plane drives itself from thrust and not though its wheels was posted, shouldnt everyone have gone...arw yes, of course. It kinda of annoyed me... maybe i'm a snob. In the office when people were arguing the toss with me over it, the most stupid thing someone said was... o.k so i could accept that the plane might stand still and then just take off after a while?!?!!!! This was one of the chaps who said i was stupid, and i wasnt getting it?!?! yet he thinks that a plane could build up thrust, not move and still take off?!?! That really annoyed me Quote Link to comment Share on other sites More sharing options...
Jay_vr6 Posted February 6, 2008 Share Posted February 6, 2008 SpiderMonkey I'm going back to page 1 and reading the lot, if its rubbish I'll be back to find you Quote Link to comment Share on other sites More sharing options...
OhGod Posted February 6, 2008 Share Posted February 6, 2008 a plane drives itself from thrust and not though its wheels The problem with this, which I tried to explain in my previous post but probably didn't do very well is it ignores the effect the wheels have on the plane, regardless of the fact they don't provide the thrust. I'll try again with my thinking; Plane is sat on the treadmill thingy, engines off. Treadmill starts up - the plane will start moving backwards with it, right? I think we can all agree on that. Therefore the treadmill, via the wheels, is applying a force on the plane pulling it backwards. Now in order to go forwards at, say, 10mph the plane will need to apply thrust usually required for 10mph *plus* a little extra to overcome the backwards force of the treadmill, yes? The backwards pull doesn't simply go away because the plane's engines have turned on. Now, as they engines begin to apply that 'bit extra' thrust, the treadmill increases speed, applying more force on the plane, in the reverse direction...? Now the plane needs to supply more thrust through it's engines...and again the treadmill increases speed. The only way you can ignore the treadmill - as some of you seem to be doing - is to assume that the wheels can somehow spin freely, with no friction or force on the plane itself. Quote Link to comment Share on other sites More sharing options...
JustGav Posted February 6, 2008 Share Posted February 6, 2008 is to assume that the wheels can somehow spin freely, with no friction or force on the plane itself. They do though I voted no before I even read it clearly and probably made a tit of myself Quote Link to comment Share on other sites More sharing options...
rpslaughter1982 Posted February 6, 2008 Share Posted February 6, 2008 quote "Plane is sat on the treadmill thingy, engines off. Treadmill starts up - the plane will start moving backwards with it, right? I think we can all agree on that. " not necessarily true, this is all down to the friction of the wheel and the hub. In previous examples when people say that they are holding the plane/cyclist/ matchbox car still on the treadmill they would only be exerting a force on the object equal to the friction forces of the object on the belt. If a brick is on the treadmill then it would move at the same speed as the belt. A tennis ball would spin and move along at a lower speed than the brick If you had a rug with a ball on it and pulled it slowly the ball would move with the rug as the friction force holding the ball would stop it moving, if you pulled the rug fast the ball would spin back and not move as fast Quote Link to comment Share on other sites More sharing options...
Supra Pilot Posted February 6, 2008 Share Posted February 6, 2008 To the 'Yes' men....... Read through the 1st 2 or 3 pages and shocked at some of the replies of some people that are wrong and strong on this! Seems Myth busters and Wikipiedia are the new Bibles in bullsh1t.... Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 To the 'Yes' men....... Read through the 1st 2 or 3 pages and shocked at some of the replies of some people that are wrong and strong on this! Seems Myth busters and Wikipiedia are the new Bibles in bullsh1t.... Care to name and shame? I read your post as you don't agree with the "yes" parties. Is this correct? Quote Link to comment Share on other sites More sharing options...
Supra Pilot Posted February 6, 2008 Share Posted February 6, 2008 Correct... 'The plane cannot take off!' I will make a simple reply maybe later on this, but first I need to go and put my skill/knowledge to use and make an Aircraft safe to fly! (in real life, not in wiki or some tele program) Rgds Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 Yes... 'The plane cannot take off!' Why? What makes you say this? Quote Link to comment Share on other sites More sharing options...
Darren-K Posted February 6, 2008 Share Posted February 6, 2008 the palne can not take of as it has zero forward velocity. and thus,no upward lift. Quote Link to comment Share on other sites More sharing options...
Supra Pilot Posted February 6, 2008 Share Posted February 6, 2008 weeehhahahkljj, i did not log off lkaj;lfjeiorj;ojl k;jnldkj jakljf;jaofjpaj;fkljal;kjf; klaj; kljfaof;klajf Quote Link to comment Share on other sites More sharing options...
caseys Posted February 6, 2008 Share Posted February 6, 2008 I wasn't making any inflamatory comments The gravity thing was a terrible pun though, I admit to that. Right, sorted then. Next up - the perennial non-question "what happens if I drive at the speed of light and turn on my headlights..." Depends. In what medium are you driving through? And are you driving in a straight line? Will Lorenz come into play? Do you have tachyon emitting headlights? If not, do you want a set? Oh no, ignore my first question, as even if it was a medium that slowed down light, you would yourself still be at the same speed as the light you're emitting. Negating that idea. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 I've just got home and realised that I was right all along. If the plane is moving at a ground speed of 0... as it will have to be if it is stationary... then there is no way that the plane can get lift once moving in said situation as the amount of air flowing over the wings is still the same as if the plane was stood still. I therefore revoke my previous statement and think that no, the plane won't take off. It will stay stationary but may well suffer from hotwheels at some point. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 I've just got home and realised that I was right all along. If the plane is moving at a ground speed of 0... as it will have to be if it is stationary... then there is no way that the plane can get lift once moving in this situation as the amount of air flowing over the wings is still the same as if the plane was stood still. I therefore revoke my previous statement and think that no, the plane won't take off. It will stay stationary but may well suffer from hotwheels at some point. Add to that: I don't see how the plane can gain forward momentum on the conveyor if it's moving at the same speed and rate of accleration. We aren't talking about the plane working against the earth, but the plane working against the surface it is resting on. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 Que Ian C. Quote Link to comment Share on other sites More sharing options...
johnnyknox Posted February 6, 2008 Share Posted February 6, 2008 I've just got home and realised that I was right all along. If the plane is moving at a ground speed of 0... as it will have to be if it is stationary... then there is no way that the plane can get lift once moving in this situation as the amount of air flowing over the wings is still the same as if the plane was stood still. I therefore revoke my previous statement and think that no, the plane won't take off. It will stay stationary but may well suffer from hotwheels at some point. I initially thought it was No..it won't take off...but It's the wheels that are the only thing making contact with the conveyor belt. The forward thrust is produced by the plane's engines, which push the plane forward. This means the wheels are working twice as hard, however power is not going to the wheels, the engines are creating thrust which has no contact with the ground..so this means the plane will move forward as normal, but the wheels will be spinning twice as fast as normal...so It will take off Quote Link to comment Share on other sites More sharing options...
AndrewOW Posted February 6, 2008 Share Posted February 6, 2008 After all these arguments for and against, i do believe that the plane will 'eventually' take off as the propeller or jet engine will move the plane forward and gradually fast enough to leave the ground. Well as long as the 'treadmill runway' is long enough, and the plane is powerful enough. I think RedM mentioned this near the start of the thread. Quote Link to comment Share on other sites More sharing options...
AndrewOW Posted February 6, 2008 Share Posted February 6, 2008 I initially thought it was No..it won't take off...but It's the wheels that are the only thing making contact with the conveyor belt. The forward thrust is produced by the plane's engines, which push the plane forward. This means the wheels are working twice as hard, however power is not going to the wheels, the engines are creating thrust which has no contact with the ground..so this means the plane will move forward as normal, but the wheels will be spinning twice as fast as normal...so It will take off Touché Its only taken 173 posts to get there, mind you! Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 OK.... imagine this: In the original scenario we have a plane completely stationary on this conveyor runway. As soon as the plane moves forward, the conveyor moves backwards to compensate. Therefore, wheels do not move. If wheels do not move from their position on the earth, plane does not move and so will be unable to create lift as there is no air flowing around the wings. Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted February 6, 2008 Share Posted February 6, 2008 OK.... imagine this: In the original scenario we have a plane completely stationary on this conveyor runway. As soon as the plane moves forward, the conveyor moves backwards to compensate. Therefore, wheels do not move. If wheels do not move from their position on the earth, plane does not move and so will be unable to create lift as there is no air flowing around the wings. wheels are connected to the plane, after all. Quote Link to comment Share on other sites More sharing options...
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