Paul_J
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Registered: 6th Jun 02
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It was steves example that made me get my head around it.
as I pictured myself at the gym, with the treadmill running putting a car on and it making a racket with the wheels wizzing underneathe - and realised I could probably just hold it there with like 1 finger and then push it lightly forward and it would go. Just would make a racket with the toy cars wheels wizzing underneath  weird image in my head - all these people thinking wtf is he doing?
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bradfincham
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Registered: 20th Sep 02
Location: East Of England Drives: Clio 172
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quote:
Originally posted by Steve
exactly the same principle though 
Yeh i know mate
Thankyou for making it so easy for myself and Paul to grasp!
Untill your example i had 2 minds about the whole situation?
Wheres Cyber gone? Back to flight simulator??
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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HERES THE PERFECT FUCKING EXAMPLE IV THOUGHT TO GET PEOPLES HEADS ROUND IT
Ok when your running on a tread mill the only reason you go nowhere is becuase your legs are pushing against amn equal momentum in the opposite direction.
Right, if you put some rollerskates on, on the treadmill, you would still be able to pull yourself to the end using your arms and a rope as easy as if you were on a fixed surface
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Paul_J
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Registered: 6th Jun 02
Location: London
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^^ I'm picturing OJC on his skates falling all over the place on a treadmill
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Cybermonkey
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Registered: 22nd Sep 02
Location: Sydney, Australia
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quote:
Originally posted by bradfincham
quote:
Originally posted by Steve
exactly the same principle though
Yeh i know mate
Thankyou for making it so easy for myself and Paul to grasp!
Untill your example i had 2 minds about the whole situation?
Wheres Cyber gone? Back to flight simulator??
get a grip, im still standing by my own conclusion of what happens. your wording was totally poor to begin with, and even after reading the question from a credible source could i understand precisely what it was saying, and i still believe an aircraft WILL NOT take off, no forward movement, no lift
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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david you tw@ i cant believe you are still arguing this, there WILL be forward movement read, my examples and realise you are wrong
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3CorsaMeal
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Registered: 11th Apr 02
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as long as the plane is moving it will take off
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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READ MY TWO EXAMPLES TO SHOW HOW THE PLANE WOULD MOVE ON THE CONVEYOR BELT
Think of it this way, push a toy car along a treadmill your arm will still move at the same rate and use the same amount of force to get it to the end as it would if the car were on a solid surface
AND
Ok when your running on a tread mill the only reason you go nowhere is becuase your legs are pushing against amn equal momentum in the opposite direction.
Right, if you put some rollerskates on, on the treadmill, you would still be able to pull yourself to the end using your arms and a rope as easy as if you were on a fixed surface. To compare, the tread mill is the conveyor belt, the rollerskates and you are the plane and its wheels, the rope is the air, and your arms are the jets pushing against the air
[Edited on 24-05-2006 by Steve]
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3CorsaMeal
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i reckon so.
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Brett
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Registered: 16th Dec 02
Location: Manchester
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I still agree with Monkey, it won't take off.
In effect the plane will be stood still
quote:
conveyor belt that is moving at the same speed as the plane
[Edited on 24-05-2006 by loafofbrett]
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Cosmo
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Registered: 29th Mar 01
Location: Im the real one!
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quote:
Originally posted by Steve
READ THESE TWO EXAMPLES TO SHOW HOW THE PLANE WOULD MOVE ON THE CONVEYOR BELT
Think of it this way, push a toy car along a treadmill your arm will still move at the same rate and use the same amount of force to get it to the end as it would if the car were on a solid surface
AND
Ok when your running on a tread mill the only reason you go nowhere is becuase your legs are pushing against amn equal momentum in the opposite direction.
Right, if you put some rollerskates on, on the treadmill, you would still be able to pull yourself to the end using your arms and a rope as easy as if you were on a fixed surface. To compare, the tread mill is the conveyor belt, the rollerskates and you are the plane and its wheels, the rope is the air, and your arms are the jets pushing against the air
[Edited on 24-05-2006 by Steve]
I understand both of these...but where is the forward momentum coming from for the plane? As the question says, the converyor belt speeds up as the plane does, so technically there would be zero airflow over the wings and therefore no lift.
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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FFS my examples make it so clear, go back to school :@mad:
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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quote:
Originally posted by Cosmo
quote:
Originally posted by Steve
READ THESE TWO EXAMPLES TO SHOW HOW THE PLANE WOULD MOVE ON THE CONVEYOR BELT
Think of it this way, push a toy car along a treadmill your arm will still move at the same rate and use the same amount of force to get it to the end as it would if the car were on a solid surface
AND
Ok when your running on a tread mill the only reason you go nowhere is becuase your legs are pushing against amn equal momentum in the opposite direction.
Right, if you put some rollerskates on, on the treadmill, you would still be able to pull yourself to the end using your arms and a rope as easy as if you were on a fixed surface. To compare, the tread mill is the conveyor belt, the rollerskates and you are the plane and its wheels, the rope is the air, and your arms are the jets pushing against the air
[Edited on 24-05-2006 by Steve]
I understand both of these...but where is the forward momentum coming from for the plane? As the question says, the converyor belt speeds up as the plane does, so technically there would be zero airflow over the wings and therefore no lift.
the forward momentum is coming from the jet engines just as it would normally.
the speed of the conveyor belt is irrelevant as the wheels will just spin faster, the jet engines pushing against the air is fixed and not effected in anyway by the conveyor belt
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bradfincham
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Registered: 20th Sep 02
Location: East Of England Drives: Clio 172
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quote:
Originally posted by Cybermonkey
quote:
Originally posted by bradfincham
quote:
Originally posted by Steve
exactly the same principle though
Yeh i know mate
Thankyou for making it so easy for myself and Paul to grasp!
Untill your example i had 2 minds about the whole situation?
Wheres Cyber gone? Back to flight simulator??
get a grip, im still standing by my own conclusion of what happens. your wording was totally poor to begin with, and even after reading the question from a credible source could i understand precisely what it was saying, and i still believe an aircraft WILL NOT take off, no forward movement, no lift
Calm down, or did you loose your sense of humour
The question is worded like that on purpose, its been posted on thousands of forums!
Ive read hundreds of replies, from RAF pilots and they all agree that the wheels have absoultely nothing to do with it, as the thrust will propell the plane down the conveyor belt as normal just the wheels will have to spin twice as fast due to the conveyor going the other way 
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Steve
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Registered: 30th Mar 02
Location: Worcestershire Drives: Defender
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yes, its blatantly obvious when you think about smaller world examples
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Cosmo
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Registered: 29th Mar 01
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quote:
Originally posted by Steve
the forward momentum is coming from the jet engines just as it would normally.
the speed of the conveyor belt is irrelevant as the wheels will just spin faster, the jet engines pushing against the air is fixed and not effected in anyway by the conveyor belt
so the plane would still move along the converyor belt, which would have to be as long as (if not longer) than a normal run way?
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Steve
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Registered: 30th Mar 02
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yes the conveyor belt would still need to be the length of the runway
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Cosmo
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Registered: 29th Mar 01
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quote:
Originally posted by Steve
yes the conveyor belt would still need to be the length of the runway
stupid fucking question, got my head round it now though. I was imagining just a short converyor belt and it trying to take of on that
Landing would be interesting though
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stuartmitchell
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Registered: 24th Apr 04
Location: Kirkliston, Edinburgh
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It will take off, read this on Integra forum
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Brett
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Registered: 16th Dec 02
Location: Manchester
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THe question is worded so that the conveyor belt equals the speed opposite to that of the plane.
The way the question is put, the plane wouldn't move at all.
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Cybermonkey
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Registered: 22nd Sep 02
Location: Sydney, Australia
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wont work, the tyres wont be able to handle the speed, they will burst and the aircraft will skid uncontrollably off the conveyor
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Cosmo
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Registered: 29th Mar 01
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quote:
Originally posted by Cybermonkey
wont work, the tyres wont be able to handle the speed, they will burst and the aircraft will skid uncontrollably off the conveyor
but atleast the passengers would get to use those blow up slide thingys!!
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RichR
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Registered: 17th Oct 01
Location: Waterhouses, Staffordshire
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even though the wheels arnt driven per se - when the aircraft is on the runway/conveyor belt - it is through these wheels that forward propulsion is achieved surely!
If the wheels and hence ground speed is set to zero - as the conveyor belt moves at the same rate as the wheels, the aircraft essentially would be stationary with NO forward propulsion!
When on the conveyor belt, with no coherent wind conditions - there would be no difference between the relative air speed and ground speed, as the two are in contact - the two can only change once the aircraft has taken off
as these two are the same, I dont see that forward propulsion would be gained
Steve using your analogy; the toy car on the tread mill - in order to remain in equilibrium ( ie not move forwards or backwards) the force from your finger and gravity must be equal and opposite to the force generated between the tread mill and wheels - in order to move the car out of a state of equilibrium you will have to overcome the force of the treadmill - by applying an accelerant! this force would in no way be equal to the force required to move the toy car whilst not on the treadmill; it would be equal to the required acceration + the force required to keep the car in equilibrium
as such, if no forward motion (thrust force) is made by the aircraft, no lift will be generated by the wings; the plane wont take off!
thats in my opinion and I've been accepted to read a Masters of Aerodynamics at Southampton University starting September 2007 - although what do I know!
[Edited on 24-05-2006 by LiVe LeE]
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gianluigi
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Registered: 9th Mar 05
Location: Ipswich, Suffolk
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Lee
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Cybermonkey
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Registered: 22nd Sep 02
Location: Sydney, Australia
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Lee, we are arguing with idiots here.
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