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Post by Dom on Feb 2, 2006 9:33:39 GMT -5
Ahh TP But if someone kept pushing you then you would go forward. No matter how fast the conveyor belt went.
My Lord I have wasted too much of my time on this really really annoying question already.
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Post by dunc85 on Feb 2, 2006 9:35:39 GMT -5
As has been said previously, the biggest misconception among the nay-sayers is that the plane gets its thrust from it's wheels. The wheels have no effect on the plane, they spin freely at the same speed as the conveyor.
The plane's engines however, are pushing against the air, moving it forward.
Do not think of the plane as a car/runner as that is completely different.
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Post by 3lbgrayling on Feb 2, 2006 9:44:33 GMT -5
zzzzzzzzzzzzzzzzzzzzzzzzzzzzz zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz zzzzzzzzzzzzzzzzzzzzzzzzzzzzz jim
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Post by Gnat on Feb 2, 2006 9:59:10 GMT -5
Remove this post to the SexyLoops forum!
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Post by clockwork on Feb 2, 2006 10:04:35 GMT -5
You are standing still on a conveyor belt with roller skates on, the wheels are not turning. Someone pushes you from behind. If the belt didn't move, you'd move forward in relation to the earth. If the belt moves, the wheels would turn but you'd go nowhere. TP, this is what the whole issue boils down to. If you had a jet engine on your back and you were wearing roller skates, you would move forwards, the thrust of the air would continually push you. The conveyor doesn't pull you backwards it just makes your wheels spin. If you believe that the conveyor pulls you backward you will always be in the no camp. If you think about the hovercraft as Dom mentioned, you will see it's the same thing (almost) although the wheels touching the moving belt will have a "tiny" effect on the forward motion. On all the forums I have just googled, the majority start at "will not fly" and most of them change sides later, leaving a few stubborn mules in the can't fly camp physics gurus, aerospace gurus and maths gurus have been at this for months it seems.
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Post by T.P. on Feb 2, 2006 10:08:54 GMT -5
As has been said previously, the biggest misconception among the nay-sayers is that the plane gets its thrust from it's wheels. The wheels have no effect on the plane, they spin freely at the same speed as the conveyor. The plane's engines however, are pushing against the air, moving it forward. Do not think of the plane as a car/runner as that is completely different. I agree with this but the plane will still not be moving forward in relation to the earth. This is an example of where your argument works really well: Think of an airboat, it has a plane engine on the back of it and no wheels. When the plane engine runs the boat moves forward across the earth, it's windy and very very noisy (and too much fun!). If there was a conveyor belt underneath it, it would make no difference. The boat is above the conveyor belt and not using it at all. This is not what is happening in a plane! A plane is attached to the ground via wheels. As hard as the plane engine will try to move the plane forward the wheels will turn. As the wheels turn they will drive the conveyor belt in the opposite direction. This will prevent the plane from gaining any ground in relation to the earth. If the plane doesn't go anywhere then no air will be displaced over it's wings to create lift. I think the trap here is thinking about jet planes and thinking that they work any differently to a kite, or paper aeroplane. The reason they have as much power as they do is because they have to reach incredible airspeeds in order to take off. Fundamentaly though the principles are the same. Like I said before it's a shame there is no definative answer. Good question though. T.P.
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Post by Sewinman on Feb 2, 2006 10:12:58 GMT -5
If the plane does take-off can it please then crash into the pro-boards server.
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Post by Silver Stoat on Feb 2, 2006 10:13:42 GMT -5
ClockWork, Dom, guinea, dunc85, I believe you are correct and my answer was totally wrong.
Regardless of what is happening at the ground/conveyer and wheel interface, the thrust of the engine(s) will move the plane foreward.
Dave.
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Post by MarkH on Feb 2, 2006 10:23:35 GMT -5
If you had a jet engine on your back and you were wearing roller skates, you would move forwards, the thrust of the air would continually push you. The conveyor doesn't pull you backwards it just makes your wheels spin. I was in the 'no' camp at the start of this but reading this and thinking about it convinced me to switch to the yes camp, for a few of seconds. You would only move forward in this case if the speed generated by forward thrust from the jet engine was greater than the speed of the roller and we are told that the speeds are constantly equalised. So I'm still in the 'no' camp, I think. ;D
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Post by clockwork on Feb 2, 2006 10:26:35 GMT -5
You would only move forward in this case if the speed generated by forward thrust from the jet engine was greater than the speed of the roller Why? you assume the roller is having an effect on the plane's forward movement. if the roller went 50 times the speed of the plane, the plane wouldn't care the wheels would get hot from mega-fast freewheeling though
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Post by clockwork on Feb 2, 2006 10:30:24 GMT -5
A plane is attached to the ground via wheels. As hard as the plane engine will try to move the plane forward the wheels will turn. As the wheels turn they will drive the conveyor belt in the opposite direction. This will prevent the plane from gaining any ground in relation to the earth. it is not attached, it is just resting on the wheels. The wheels on a plane are not used to drive it, just to keep it scraping the runway when it lands and to reduce friction at take off. A plane taking off on snow with skis would be a good thing to think about. If the Skis were well waxed and the conveyor had snow on it.
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Post by MarkH on Feb 2, 2006 10:32:03 GMT -5
Why? you assume the roller is having an effect on the plane's forward movement. if the roller went 50 times the speed of the plane, the plane wouldn't care Mmmmm. If the plane's engines were switched off it would freewheel and remain stationery. I wouldn't be dragged backwards, suggesting that the roller does not have an effect on the plane's movement, as you say. Oh I don't fecking know ...
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Post by traprain on Feb 2, 2006 11:40:36 GMT -5
of course it will take off
provided the wheels of the plane are free-spinning it is irrelevant how fast the runway is moving
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Post by JonMartin on Feb 2, 2006 12:26:17 GMT -5
Think rocket plane, missile, both will become airborne from a stationary launch position.
As the man said, "for every action there is an equal and opposite reaction".
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flyonly2006
Full Member
My favourite Perthshire Hill Loch
Posts: 139
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Post by flyonly2006 on Feb 2, 2006 12:37:06 GMT -5
If the plane's engine power is adjusted to match the speed of the conveyor and achieve a static position there is no way take off will be achieved as there would be no air flowing over the wings.
Anyway, which airline is trying this - RyanAir? 'cause these bastards will try anything to delay your flight.
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