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Post by nemesis on Feb 14, 2008 0:56:08 GMT 1
I'm sticking by my original post and and backing up Mike. It makes no diff how big the plane is, how powerful or what type of engine(s) it has, what the wheels are or aren't doing or how fast the conveyor belt is going. If there is no airflow over the wings, that airplane is staying firmly on the ground. Without airflow over the wings, it's a car, lol. This is why aircraft can stall at low speed. The airflow over the wings drops to to the point where they can no longer produce lift and the aircraft becomes an expensive brick. Would I lie to you?..... hmm?
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Post by Mark on Feb 14, 2008 2:47:55 GMT 1
That second video shows exactly what we're trying to say. That lil aircraft was sat on that treadmill at a registed speed of ten miles an hour, more than enough to lift it off the ground if it were travelling forward at that speed. Because it was stationary with no actual airflow, it happily stuck to the ground. True, but the engine power was very low. Full throttle is not needed because there was no air resistance to overcome or lift to generate. If the conveyor was switched off, the plane would only trundle along the ground very slowly at the same power, and would not take off. Have another read of the question. It simply states that the conveyor belt moves backwards at the same speed as the aircraft moves forwards. I.e. The conveyor moves to match the plane, not the other way round. In the 'doesn't take off idea' the plane is staying still, so the conveyor should be staying still. I.e. The plane is parked !
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Post by swanrail on Feb 14, 2008 12:41:37 GMT 1
From my own experience of travelling in the cockpit of a 737 (as an observer I hasten to add) the rotation (lift off) speed was about 140mph. With my previous post, the friction giving rise to a false airflow would be such that the belt would have to move at least twice this speed to generate the 140mph airflow by friction. and probalby more. At 10 mph, forget it!! The frictional airflow would be neglible, so it all comes down to what type of aircraft and what speeds are involved. I guess a model dong 140mph would not last very long!!! All aircraft have differing take off speeds, due to weight and wing design - look at the Lysanders used during the war!! A puff of wind would get them up, al la gliders.
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Post by Mike B on Feb 14, 2008 15:59:24 GMT 1
I'm sticking by my original post and and backing up Mike. Hi Nem, Doesn't it feel great to be one of the few people right about this question? ;D ;D ;D
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Post by nemesis on Feb 14, 2008 17:35:46 GMT 1
Lol Mike. It's a heavy burden being a genious ain't it? ;D
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Post by Mike B on Feb 14, 2008 19:07:26 GMT 1
Lol Mike. It's a heavy burden being a genious ain't it? ;D Quad erat demonstrandum!
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Post by nemesis on Feb 14, 2008 20:16:42 GMT 1
Or, as i prefer to quote... "Audentis fortuna iuvat".
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Post by eric on Feb 14, 2008 20:50:53 GMT 1
Fancy words don' make ya right, y'know!
And besids which, it WAS demonstrated earlier! The plane took off!!!!!
The belt went backwards....the prop pulled the aircraft through the air (the whole point of it)...and it took off, with it's wheels going round like crazy.
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Post by nm on Feb 14, 2008 21:21:12 GMT 1
Quid quad? Quod?
NM
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Post by nemesis on Feb 15, 2008 1:03:56 GMT 1
Eric, the only thing that video proved was that the aircraft was moving too fast for the conveyor belt to keep up. The original question was, would the aircraft take off if the conveyor belt matched the aircraft's speed in the oposite direction. and the answer is still no, lol.
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Post by Baz on Feb 15, 2008 8:42:56 GMT 1
I can't believe the amount of huff and puff this has caused. Stick to your guns nemisis ;D afkmatrix - you should be shot. I checked out the original site and the video. Haven't gone through it with a fine tooth comb, but to my way of thinking, the question is a bit obtuse anyway. If the question is intended in such a way that the plane stays stationary the answer in my humble opinion is definitely - NO Why? noooooo air current across the wing to create lift. If the question has the intention to allow for other forces to intervene and the plane can move forward, then the answer is - YES. Why, forward movement = air movement across the wings creating lift - ergo, up goes plane. The video showed forward movement of the plane. What a load of Crap about wheel speed..........not relevant How does that sound Nem Bazza - an upside down view of it all ! YEAH ITS FRIDAY NIGHT - Thinks.................when can I take next holidays ??
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Post by Baz on Feb 15, 2008 8:58:18 GMT 1
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Post by Baz on Feb 15, 2008 9:01:55 GMT 1
Hey you guys.............. where did all this latin stuff come from Thats not fair. Get intoum Nappy
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Post by Baz on Feb 15, 2008 9:13:25 GMT 1
MMMMMmmmmmmmmmmm Bazza thinks...........................gooogle maps............... ............I see no Mitcham in France
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Post by Mark on Feb 15, 2008 9:15:44 GMT 1
.......I see no Mitcham in France But there are some French in Mitcham
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