Robin
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quote:
Originally posted by Colin
quote:
Originally posted by Robin
lets use the car as an example, as you brought it up.
if you sit a car on a conveyor belt which is doing 50mph, the wheels on the car would spin yes?
no
If you drove onto a conveyor belt doing 50mph & the conveyor belt was doing 50mph you would slow gradually until you remain pretty much at a standstill
no, i meant if the car was in neutral, you parked on a belt, and the belt went from 0-50 instantly, the wheels would turn.
same with the plane. then the plane has the ability to apply force which isn't connected to the wheels, meaning it would move forward, and thus take off.
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Brett
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The plane is using air to push, not the ground. It has wheels that will just freely spin and go nowhere.
If you put the brakes on the wheels, then yes it'd go backwards.
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Robin
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quote:
Originally posted by Colin
what about making it really simple, see those flat escilators they have at the airpost to take you to the terminal from main building, if you jump onto one of them the wrong way & start walking (at a simmilar pace to the machine) do you go anywhere
but if you walk faster, you do.
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Robin
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quote:
Originally posted by M2RTY
quote:
Originally posted by loafofbrett
OK...
Imagine you are on a tread mill with roller skates on.
You have a friend pushing you from behind (he's the jet engines).
He'll still be able to push you forward all day long as the skates are just free wheeling.
no as you will now be moving at the same speed as the treadmill in the opposite direction = still relitive to the ground
correct. then your friend is adding MORE thrust, which would move you forward.
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Colin
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So the planes already on the conveyor belt & its moving Im confused.....theres so many variables to take into account, i summerise it may take off depending on which of those are in its favour!!
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Colin
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quote:
Originally posted by Robin
quote:
Originally posted by Colin
what about making it really simple, see those flat escilators they have at the airpost to take you to the terminal from main building, if you jump onto one of them the wrong way & start walking (at a simmilar pace to the machine) do you go anywhere
but if you walk faster, you do.
Yes, which was what I said if the plane thrusts faster it will take off!!
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Robin
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exactly.  I thought you were saying it wouldn't :lol;
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Colin
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Nope it will so long as the force excerted by the plane exceeds that excerted by the moving runway. Think that was the point Marv was making too.
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Colin
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Like if you went onto a conveyor belt & only gave the plane say 1/8th thrust it would probably go backwards, 1/2 sitting still, full thrust it would start going forwards. Depends on a huge amount of variables, probably loads we havnt taken into account also.
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MarkM
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Would the plane not need a LOT of forward force from the engines to build its speed up to take off speed?
Compared to a normal ground not moving?
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Colin
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quote:
Originally posted by MarkM
Would the plane not need a LOT of forward force from the engines to build its speed up to take off speed?
Compared to a normal ground not moving?
Probably so, would need a science boffin to work out how much, planes werent designed to take off from conveyor belts
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Robin
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It would need more thrust Mark, but not a massive amount more, as the friction from the wheels wouldn't affect it that much.
For the friction to matter, the wheels would not turn when you landed.
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Colin
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I think 99 times out of 100 if you tried to land on a conveyor belt you would crash
Edit - Infact of course the wheels would turn it wouldnt just stop instantainously, it would just slow down quicker
wheels are connected to 100 tones of plane & when that hits a runway doing whatever speed they land at of course its going to keep going forward, then the conveyor will catch up on the forward force being bared upon it & stop - quicker than normal landings.
[Edited on 09-01-2007 by Colin]
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MarkM
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Surely this has been tested somewhere...
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Russ
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quote:
Originally posted by Colin
what about making it really simple, see those flat escilators they have at the airpost to take you to the terminal from main building, if you jump onto one of them the wrong way & start walking (at a simmilar pace to the machine) do you go anywhere
do your feet freewheel coling
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Jules S
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I still like my reverse engineering that says the plane would have to stop dead when landing on the conveyor belt*
*If it couldn't take off from it
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Colin
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quote:
Originally posted by Russ
quote:
Originally posted by Colin
what about making it really simple, see those flat escilators they have at the airpost to take you to the terminal from main building, if you jump onto one of them the wrong way & start walking (at a simmilar pace to the machine) do you go anywhere
do your feet freewheel coling
That was a loose example, the plane moving has nothing to do with freewheeling & its wheels not being powered, its all to do with the forces being exerted in a particular direction.
If I push you you fall??? If you push me back at the same time you dont fall!! Theres another example!!
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Colin
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quote:
Originally posted by Jules S
I still like my reverse engineering that says the plane would have to stop dead when landing on the conveyor belt*
*If it couldn't take off from it
Passengers would recieve some awful whiplash
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Russ
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quote:
Originally posted by Colin
quote:
Originally posted by Russ
quote:
Originally posted by Colin
what about making it really simple, see those flat escilators they have at the airpost to take you to the terminal from main building, if you jump onto one of them the wrong way & start walking (at a simmilar pace to the machine) do you go anywhere
do your feet freewheel coling
That was a loose example, the plane moving has nothing to do with freewheeling & its wheels not being powered, its all to do with the forces being exerted in a particular direction.
If I push you you fall??? If you push me back at the same time you dont fall!! Theres another example!!
if you push me when i have roller skates on..
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Colin
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If I push you when you have rollerskates on yes you'll go backwards but then if you have a jato rocket booster stuck to your ass putting out 3000Nm of thrust you will go forwards. If I can match the force of the force of the Jato you will go nowhere. You comprende
[Edited on 09-01-2007 by Colin]
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Robin
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If you could create enough force to counteract the 3000Nm by friction in the wheels, yeah, you'd stay still.
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ed
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quote:
Originally posted by Antz
I only read to page 2... but I actually wrang Rolls Royce and they said hundreds of people ring up about this every day, they didn't have enough time to explain the dynamics of this but IT WOULD TAKE OFF!
You did what to them?
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Ally
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Wrang, like wrung where you squeeze the water out...
at a guess
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Colin
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Who would be prepared to be a test dummy in the plane taking off & landing on a conveyor belt?? Im going to write to Stellios @ Easy Jet & C-Trak Conveyors Ltd to see if we can answer this once & for all....maybe even get a trial take off & landing!
Need some volenteres
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Robin
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If only Jim'll fix it was still on tv  
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