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gpssti4 27 November 2012 02:03 PM

Question.
 
Stolen from another forum.....

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?

So can it, or can't it?

mike74 27 November 2012 02:07 PM

They actually did this on episode of Mythbusters, can't remember the outcome though!

CrisPDuk 27 November 2012 02:17 PM

Whether or not a plane takes off has nothing to do with it's speed over the ground, it's airspeed over (and under) the wings that matters. So if you've got that, yes the plane will take off, if you haven't, no it won't. Simples :)

gpssti4 27 November 2012 02:18 PM


Originally Posted by mike74 (Post 10885319)
can't remember the outcome though!

Doh!

gpssti4 27 November 2012 02:19 PM


Originally Posted by CrisPDuk (Post 10885334)
Whether or not a plane takes off has nothing to do with it's speed over the ground, it's airspeed over (and under) the wings that matters. So if you've got that, yes the plane will take off, if you haven't, no it won't. Simples :)

Indeed, as the wheels aren't driven I don't see how the conveyor makes any difference. 85 pages on one of the Vauxhall forums. :luxhello:

TelBoy 27 November 2012 02:20 PM

On a forum of users familiar with rolling roads, i'm sure everybody knows the answer :)

gpssti4 27 November 2012 02:25 PM


Originally Posted by TelBoy (Post 10885339)
On a forum of users familiar with rolling roads, i'm sure everybody knows the answer :)

Yes, with a remap and a dump value it will take off. :thumb:

TelBoy 27 November 2012 02:27 PM

A dump value :Suspiciou

f1_fan 27 November 2012 02:27 PM


Originally Posted by CrisPDuk (Post 10885334)
Whether or not a plane takes off has nothing to do with it's speed over the ground, it's airspeed over (and under) the wings that matters. So if you've got that, yes the plane will take off, if you haven't, no it won't. Simples :)

This ^^^

gpssti4 27 November 2012 02:28 PM


Originally Posted by TelBoy (Post 10885351)
A dump value :Suspiciou


Hmmm fat finger and and iPad don't mix.






Or maybe it was autocorrect. :Suspiciou

Camsedin 27 November 2012 02:28 PM

the plane wont take off if its standing still.

a plane needs wind/air going over/under the wings to give it lift.


aw someone beat me to it :)

TelBoy 27 November 2012 02:30 PM

Why doesn't it surprise me that it took a Vauxhall forum 85 pages to see sense :wonder:



:norty:

gpssti4 27 November 2012 02:32 PM


Originally Posted by TelBoy (Post 10885356)
Why doesn't it surprise me that it took a Vauxhall forum 85 pages to see sense :wonder:



:norty:

More importantly, why was I on a Vauxhall forum :wonder:

Miniman 27 November 2012 02:37 PM

Surely it's the air moving over the wings that creates the lift (pressure differences etc etc). So unless the conveyor is moving the air a few feet above it, then no lift will be generated and no the plane won't take off.

TelBoy 27 November 2012 02:43 PM

If only somebody had suggested that before, Miniman :cry:

ReallyReallyGoodMeat 27 November 2012 02:46 PM

The Bernoulli effect.

jonc 27 November 2012 03:12 PM

No it won't take off.................84 pages to go........

Leslie 27 November 2012 03:57 PM

The groundspeed in this case would not influence the airspeed which is what enables the aircraft's wings to produce lift.

It would not fly.

Les

Ian 27 November 2012 04:04 PM

will the engine be running? if it is, wont that make air flow over the wings etc?

TelBoy 27 November 2012 04:09 PM

Ian if this gets even to page 3 i'm holding you personally responsible :mad:

Jamie 27 November 2012 05:04 PM


Originally Posted by gpssti4 (Post 10885314)
Stolen from another forum.....

A plane is standing on a runway that can move (some sort of band conveyer). The plane moves in one direction, while the conveyer moves in the opposite direction. This conveyer has a control system that tracks the plane speed and tunes the speed of the conveyer to be exactly the same (but in the opposite direction). Can the plane take off?

So can it, or can't it?

What cave have you been living in ? or was it prison? ph many moons years ago:lol1:

Ian 27 November 2012 06:07 PM


Originally Posted by TelBoy (Post 10885467)
Ian if this gets even to page 3 i'm holding you personally responsible :mad:


;-)

gpssti4 27 November 2012 06:09 PM


Originally Posted by Jamie (Post 10885552)
What cave have you been living in ? or was it prison? ph many moons years ago:lol1:


<<<< look at where I live. We've only just got electricity. :razz:

jonc 27 November 2012 06:34 PM

Does this question apply to VTOL planes?

addi monster 27 November 2012 06:39 PM

The plane will take off simples, the plane builds up speed from the propeller ect pulling it through the air not from wheels pushing it accross the ground so no matter whether its on a treadmill or not the propellor will pull it up to speed and take off.

Aaron1978 27 November 2012 06:55 PM


Originally Posted by addi monster (Post 10885667)
The plane will take off simples, the plane builds up speed from the propeller ect pulling it through the air not from wheels pushing it accross the ground so no matter whether its on a treadmill or not the propellor will pull it up to speed and take off.

Have you missed out a smiley? As it clearly won't in the scenario in post 1;)

addi monster 27 November 2012 07:01 PM


Originally Posted by azz250478 (Post 10885690)
Have you missed out a smiley? As it clearly won't in the scenario in post 1;)

Did you not read what i posted ? ;)
The wheels do not play a part in the take off (no drive at all) so even if the conveyor was doing 10 million mph the plane would still move forward.


jonc 27 November 2012 07:04 PM

The plane wont take off. If the planes like 747 jumbo have a take off speed of 200mph, the conveyor belt runway would also move in the opposite direction, thus the wheels would be rolling at 400mph which far exceeds the design spec of the wheels, tyres and bearings. Therefore these wheels will explode rupturing the fuselage and wings and the plane will explode into massive ball of fire along with all the passengers. Therefore nobody should ever try this to prove me wrong.

addi monster 27 November 2012 07:15 PM


Originally Posted by jonc (Post 10885701)
The plane wont take off. If the planes like 747 jumbo have a take off speed of 200mph, the conveyor belt runway would also move in the opposite direction, thus the wheels would be rolling at 400mph which far exceeds the design spec of the wheels, tyres and bearings. Therefore these wheels will explode rupturing the fuselage and wings and the plane will explode into massive ball of fire along with all the passengers. Therefore nobody should ever try this to prove me wrong.

The OP said " A PLANE" not specific in any way so see my above post and it will take off, point taken about huge aircraft ratings ect but a plane will indeed take of under the circumstances :thumb:

TelBoy 27 November 2012 07:21 PM

:cry:


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