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For every action there must be an equal and opposite reaction. In the case of a plane, the reaction of the engines is that of motion, against a stationary runway. If the runway is moving, the two are cancelled out and there will be no motion. And without motion there will be no lift.
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Do you know that, with a 50 character limit, it's -
The plane should take off, but will need more thrust in proportion to a 'normal' take off to counter a slightly greater degree of friction on the wheels from the conveyor.
As the plane uses thrust to achieve air speed, the engine will need to have sufficient thrust to generate the airspeed needed to lift off - the wheels on the conveyor are irrelevant.
The only drawback with this theory is that the plane needs to be moving through air, as it is the resistance generate by this air that lifts the plane, but if there is enough thrust then you may be able to lift off without the air under the wings - long shot I know, but theoretically possible.....Too old to care, young enough to rememberComment
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well to put it bluntly, anyone wanting to know the answer needs to watch mythbusters, they answer it and the pilot of the aircraft gets it wrong,
the way most people look at it is that they automatically think of the aircraft similar to a car,
in fact due to the fact that there is no drive whatsoever through the wheels of the plane , the speed of the conveyor belt is completely irrelevant,
THE PLANE WILL TAKE OFF!!!PayPal for stickers : scuffsnscrapes@hotmail.comComment
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What makes you think I'm going to? I haven't stated yet which answer I believe to be true. But it is interesting watching you lot explain your answers, and seeing some of you make incorrect analogies/assumptions.Originally posted by MOTRAV View PostYa canae change the laws of physics captain !!!!!!!!!!!!!!!!!!!!!!!!!!
When the aircraft reaches V1 speed (approx 186 mph For a fully laden 747) although the conveyor belt will be moving backwards at the same speed it bears no relation to the forward movement of the plane . When the airflow over the wings reach the pint where the centre of gravity moves rearwards the nose will lift this takes one set of wheels out of the equation . when the aircraft reaces V2 (approx 206mph for a fully laden jumbo jet ) unstick will happen and the aircraft will fly .
Please refer to Boyles law of thermodynamics and Newtons 3rd law .
PICK THE BONES OUTTA THAT slugsie
Mo
Paul </Slugsie>
Immortal.so far!
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Bugger, you weren't supposed to bring that up. This episode of Mythbusters (which airs tomorrow night in the US) is what started this off.Originally posted by animal View PostPaul </Slugsie>
Immortal.so far!Comment
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Gah, dont be stupid!...
However, if the belt goes fast enough, there will be some air movement caused by friction. Assuming no speed limit, there will come a point when the belt is moving fast enough to generate sufficient airflow to lift the aeroplane. (Not correct spelling, rather than americanism)Cutting steps in the roof of the worldComment
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I'm honestly not that fussed, I just like answering these type of questions using both possible answers.
Another way to look at it is this: If the plane is suspended from a big bit of string, like a clothes line, with a conveyor belt under it, but with its undercarriage up and therefore not touching the conveyor. Same rules apply, plane moves forward at 10mph, conveyor belt moves back at 10mph.
Now would it take off? Of course it would, so what's different about the way a plane generates thrust and lift in this scenario?Do you know that, with a 50 character limit, it'sComment
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May I pick the bones outta that?Originally posted by MOTRAV View PostYa canae change the laws of physics captain !!!!!!!!!!!!!!!!!!!!!!!!!!
When the aircraft reaches V1 speed (approx 186 mph For a fully laden 747) although the conveyor belt will be moving backwards at the same speed it bears no relation to the forward movement of the plane . When the airflow over the wings reach the pint where the centre of gravity moves rearwards the nose will lift this takes one set of wheels out of the equation . when the aircraft reaces V2 (approx 206mph for a fully laden jumbo jet ) unstick will happen and the aircraft will fly .
Please refer to Boyles law of thermodynamics and Newtons 3rd law .
PICK THE BONES OUTTA THAT slugsie
Mo
The CoG NEVER moves rearward, unless you want an unstable aeroplane...
Simply, lift becomes sufficient to outweigh gravity and drag and the wing acheives flight.
Bah! Armchair aerodynamicists!!!Cutting steps in the roof of the worldComment
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You're getting airspeed mixed up with groundspeed. There is no forward motion. In the original premise, the groundspeed is cancelled out, and so is the airspeed. Without airspeed, 'planes dont fly. They just fall and give us material for 'Air Crash Investigation' and 'Seconds From Disaster'Originally posted by animal View Postyes it will fly, because its the thrust from the engines that gets the plane moving and they are not driven by the wheels , therefore no matter how fast the conveyor belt is moving, the wheels will be spinning faster and faster but will not be slowing the plane down
so for the plane to be doing 10mph for example, it must be phisically moving through the air, not have its wheels moving that fast!
therefore there will be lift and the plane will take offCutting steps in the roof of the worldComment
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PayPal for stickers : scuffsnscrapes@hotmail.comComment
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In your original premise, there was no mention of driven wheels, only speed. One moves forward by the same amount as the other moves backward. No airspeed, no flight. I dont give a flying (or non- in this case) f*** what mythbusters says.Originally posted by Slugsie View PostCutting steps in the roof of the worldComment
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Surely airspeed would be measured in knots, rather than MPH....
it's in me shed, mate.Comment
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...but thinking some more (this is whoring at its best), if it IS a trick question, and the whole assembly is moving forward at a speed equivalent to the drive of the conveyorbelt moving backwards (converyor on a very fast, very large lorry!) then there will be airspeed, but thats b0llocks and cheating.
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if a plane landed on a conveyor belt would it be bumpy??nee nar nee nar, i'm a fire engine!Comment
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Dunno, at 2500mph, you have to be able to count the bumps on that rope pretty fast!Originally posted by Chillitt View PostSurely airspeed would be measured in knots, rather than MPH....Cutting steps in the roof of the worldComment
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