M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by Robin
if the belt was travelling at the exact opposite speed to the speed of the plane with that amount of thrust on a normal runway, the plane would take off, as the friction in the wheel hubs would not slow the plane enough.
the belt would need to be travelling considerably faster than the plane would be on a normal runway.
a plane takes off at 150mph lets say, so the plane on a conveyor belt moving at 150mph in the opposite direction would still move, as the wheels are turning.
if the belt was travelling at enough speed to create the friction to slow the plane, you are right, it would not take off, but that speed would be greater than the take off speed of the plane.
NO NO NO
150mph + -150mph = 0
NOTHING
NO MOVEMENT
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by CorSRi_BT
quote:
Originally posted by M2RTY
the plan will be stood stationary
Not if the plane is moving faster than the belt.
If you are running on a treadmill it doesn't speed up when you do.
yes which is why i pointed out the different senarios
if the plane was travelling at 50mph on a belt ALSO moving in the same direction at 50mph then the plane would take off as
50 + 50 = 100mph
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by M2RTY
or in a simple mathmatic equation
for arguments sake lets use 100mph as the speed which the plane leaves the belt and flys
if plane = 100mph and belt = 0 then the plane will fly (the belt is not moving)
e.g 100 + 0 = 100
if plane = 100 and belt = -100 then the plane will remain stationary (the belt is moving the same speed as the plane in the opposite direction)
e.g 100 + -100 = 0
if plane = 100 and belt = -50 (i.e half the speed of the plane) then the plane will move at half the speed relitive to the ground but not take off as it does not have the 100mph speed it requires
100 + -50 = 50
|
Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
|
no it doesn't.
you are assuming that the wheels are not freewheeling 
stand on a treadmill in some rollerskates whilst holding on to the bar, then tell me that the treadmill moving makes you move.
if you add some thrust, you will move forward.
to counteract that, you need to move the treadmill faster than the speed you would be doing on solid ground.
for 150 + -150 to = 0, you would need more resistance on the bearings in the wheel hubs, which would stop the wheels turning when you land... which we know doesn't happen.
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
instead of the plane pushing itself forward at 100mph it will push the belt back at 100mph
= no movement
|
Dave
Member
Registered: 26th Feb 01
Location: Lancs
User status: Offline
|
No it won't, the wheels are irrelevant as they aren't powered. The thrust is produced by air rushing out of the back of the engine, increasing the speed of the conveyor just increases the speed of the wheels and has very little, if any effect on the plane.
|
Scotty_B
Member
Registered: 11th Jun 03
Location: East Kilbride
User status: Offline
|
quote:
Originally posted by M2RTY
instead of the plane pushing itself forward at 100mph it will push the belt back at 100mph
= no movement
Depends what type of conveyor belt it is.
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by Robin
if you add some thrust, you will move forward.
no you wont
if a treadmill was moving at 5mph and you added enough thrust to move 5mph you would stay the same
this is THE SAME as holding the treadmill, the same force is required to move you 5mph forward
both cancel out the speed of the treadmill seperatly you can not do both at the same time
[Edited on 09-01-2007 by M2RTY]
|
Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
|
I 100% guarantee I can pull myself forward on a treadmill whilst wearing rollerskates.
If I was to strap a rocket to my back, I would move forward.
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by CorsaDave
No it won't, the wheels are irrelevant as they aren't powered. The thrust is produced by air rushing out of the back of the engine, increasing the speed of the conveyor just increases the speed of the wheels and has very little, if any effect on the plane.
no
if the power comes from the wheels or turbines on the wings it does not matter
it could come from 100 people running, it does not matter
it is the direction that counts, not the way it moves
if you drive a car on a conveyerbelt at the same speed it is moving or in a plane or swim against a current with the same opposite speed you will remain in the EXACT same possition
|
Brett
Premium Member
Registered: 16th Dec 02
Location: Manchester
User status: Offline
|
m2rty, you are wrong, this thread is sooo last year 
|
Leighton
Member
Registered: 21st Feb 01
Location: Liverpool
User status: Offline
|
quote:
Originally posted by Robin
if the belt was travelling at the exact opposite speed to the speed of the plane with that amount of thrust on a normal runway, the plane would take off, as the friction in the wheel hubs would not slow the plane enough.
the belt would need to be travelling considerably faster than the plane would be on a normal runway.
a plane takes off at 150mph lets say, so the plane on a conveyor belt moving at 150mph in the opposite direction would still move, as the wheels are turning.
if the belt was travelling at enough speed to create the friction to slow the plane, you are right, it would not take off, but that speed would be greater than the take off speed of the plane.
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by Robin
I 100% guarantee I can pull myself forward on a treadmill whilst wearing rollerskates.
If I was to strap a rocket to my back, I would move forward.
yes
but what does the plane hold on to?
nothing
there is nothing constant between the stationary ground and the plane which makes your theory irrelivant
|
Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
|
And you wouldn't need 5mph worth of force to move, you would need less, as the treadmill would not be putting 5mph of backwards motion on the wheels, as the wheels are turning.
|
Colin
Member
Registered: 4th Apr 02
User status: Offline
|
quote:
Originally posted by Robin
I 100% guarantee I can pull myself forward on a treadmill whilst wearing rollerskates.
If I was to strap a rocket to my back, I would move forward.
I really think we need to see that
VIDS
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by loafofbrett
m2rty, you are wrong, this thread is sooo last year
so when the plane leaves the belt, what speed does it move at if it needs to go at a constant 100mph to fly?
its impossible
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
quote:
Originally posted by Robin
And you wouldn't need 5mph worth of force to move, you would need less, as the treadmill would not be putting 5mph of backwards motion on the wheels, as the wheels are turning.
ok, force to EQUAL 5mph in movement
|
Colin
Member
Registered: 4th Apr 02
User status: Offline
|
Way I see it is if you roll onto something exerting a force this way <- & your exerting an equal force that away -> you wont move!! Basic law's of physics 
|
Robin
Premium Member
Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
User status: Offline
|
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?
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
i gtg as ive finished work
basic physics say
if one thing moves X in one direction and another moves -X
then X + -X = 0
nothing
[Edited on 09-01-2007 by M2RTY]
|
Brett
Premium Member
Registered: 16th Dec 02
Location: Manchester
User status: Offline
|
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.
|
Colin
Member
Registered: 4th Apr 02
User status: Offline
|
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
|
Dave
Member
Registered: 26th Feb 01
Location: Lancs
User status: Offline
|
quote:
Originally posted by M2RTY
quote:
Originally posted by CorsaDave
No it won't, the wheels are irrelevant as they aren't powered. The thrust is produced by air rushing out of the back of the engine, increasing the speed of the conveyor just increases the speed of the wheels and has very little, if any effect on the plane.
no
if the power comes from the wheels or turbines on the wings it does not matter
it could come from 100 people running, it does not matter
it is the direction that counts, not the way it moves
if you drive a car on a conveyerbelt at the same speed it is moving or in a plane or swim against a current with the same opposite speed you will remain in the EXACT same possition
But thats the point, a car travelling on a conveyor would be stationary if the speeds were equal, just like running on a treadmill. However, the wheels on a plane are not driven like the wheels of a car or the legs of a human, they just sit there acting like bearings while the engines suck in air and blast it out of the back, creating thrust.
Next time you are at Asda buy a toy car, put it on the conveyor and push, you'll see what I mean.
|
M2RTY
Member
Registered: 25th May 01
User status: Offline
|
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
|
Colin
Member
Registered: 4th Apr 02
User status: Offline
|
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
|
