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| Will the plane take off? |
| Yes it will |
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38% |
[ 10 ] |
| No it wont |
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61% |
[ 16 ] |
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| Total Votes : 26 |
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JongnoGuru
Joined: 25 May 2004
Location: peeing on your doorstep
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 Posted: Mon Dec 05, 2005 11:21 pm Post subject: |
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Despite being mentioned, red-herring fashion, in the question as posed in the OP, I'm not really understanding why all the focus on the speed of the conveyor belt and the speed of the wheels. I say forget them both.
In fact, just image this hypothetical aircraft HAS NO WHEELS, and the runway HAS NO CONVEYOR BELT. Imagine this plane is being magically SUSPENDED IN MID-AIR. (by Messrs Copperfield & Blaine, if you must)
It will fly for the same reason that massive planes can perform takeoffs on water or ice, where there is little to zero traction whatsoever. Engine thrust.
(no?) |
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Pligganease
Joined: 14 Sep 2004
Location: The deep south...
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| Posted: Mon Dec 05, 2005 11:38 pm Post subject: |
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Imagine that you have the same conveyor belt, except that it is miniature and small enough to fit on your desk. However, instead of an airplane, you have a car.
The car and the conveyor are matching opposite speeds, and have a net velocity of 0.0000km/h. This is where I was when I was thinking the other way...
The point Hypnotist was making was that if you have this state of zero net velocity, it is irrelevant to the engines of the aircraft that are independent of the ground and conveyor.
So you have this miniature conveyor/car set on your desk. Imagine your hand is the jet/prop engine that is independent of the ground. If you reach down and push the car forward with your finger, will it move forward? Yes. This is the point I was missing. The engines will move the plane forward regardless of the conveyor and, therefore, lift will be created. |
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Swiss James
Joined: 26 Nov 2003
Location: Shanghai
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| Posted: Tue Dec 06, 2005 12:12 am Post subject: |
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| JongnoGuru wrote: |
Despite being mentioned, red-herring fashion, in the question as posed in the OP, I'm not really understanding why all the focus on the speed of the conveyor belt and the speed of the wheels. I say forget them both.
In fact, just image this hypothetical aircraft HAS NO WHEELS, and the runway HAS NO CONVEYOR BELT. Imagine this plane is being magically SUSPENDED IN MID-AIR. (by Messrs Copperfield & Blaine, if you must)
It will fly for the same reason that massive planes can perform takeoffs on water or ice, where there is little to zero traction whatsoever. Engine thrust.
(no?) |
Of course- I reckon as long as it can keep straight it'll take off much easier this way, because it won't have to overcome the friction of the wheels on the ground to reach its top speed either.
The key is that if you're standing at X looking at the cockpit on the conveyor belt,
>===o
o o
_______
X
then at some point the thurst of the engines will be too much and this will happen
>===o
o o
_____________
X
>===o
o o
_____________
X
>===o
o o
_____________
X
>===o ^
o o ^
_____________
X!!
because the wheels insane spinning become ineffective at overcoming the huge thrust of the planes desire to move forward.
Then everybody can go home and have a nice slice of battenburg cake. |
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jazblanc77
Joined: 22 Feb 2004
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| Posted: Tue Dec 06, 2005 7:32 am Post subject: |
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| deessell wrote: |
Are you watching Myth Busters on the Discovery Channel???  |
It runs on Wednesdays at 10pm so, probably not! |
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huck
Joined: 19 Jan 2003
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| Posted: Tue Dec 06, 2005 8:14 am Post subject: |
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| So let's say the wheels are locked - they won't spin - and there is no conveyor belt. You're saying that the thrust of the engines is strong enough to push the plane on wheels that are locked up? |
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Ya-ta Boy
Joined: 16 Jan 2003
Location: Established in 1994
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| Posted: Tue Dec 06, 2005 4:21 pm Post subject: |
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| I want someone to film a demonstration of this. |
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hypnotist
Joined: 04 Dec 2004
Location: I wish I were a sock
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| Posted: Tue Dec 06, 2005 4:31 pm Post subject: |
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| huck wrote: |
| So let's say the wheels are locked - they won't spin - and there is no conveyor belt. You're saying that the thrust of the engines is strong enough to push the plane on wheels that are locked up? |
I don't quite see what this has to do with the scenario we're discussing, but for some planes I believe this is indeed the case. Some fighter jets are powerful enough to jump out of their chocks, too. |
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Wangja
Joined: 17 May 2004
Location: Seoul, Yongsan
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| Posted: Tue Dec 06, 2005 4:41 pm Post subject: |
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Forget wheels: forget floats: forget propellors: forget jets.
If the wings do not pass through the air to generate lift the plane does not fly. |
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hypnotist
Joined: 04 Dec 2004
Location: I wish I were a sock
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| Posted: Tue Dec 06, 2005 4:53 pm Post subject: |
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| Wangja wrote: |
Forget wheels: forget floats: forget propellors: forget jets.
If the wings do not pass through the air to generate lift the plane does not fly. |
We know, we know, we know 
My position is that the aircraft (and thus its wings) does move through the air.
This is what I was arguing when Pligganease had his* Damascusian conversion. The conveyor can't stop the plane moving forward.
* hope that's right  |
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Wangja
Joined: 17 May 2004
Location: Seoul, Yongsan
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| Posted: Tue Dec 06, 2005 5:34 pm Post subject: |
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Every time I post on this thread I feel as if I am losing one IQ point. 
I understand the logic that as there is no connection between the wheels (which are free to revolve and independent of the thrust) and the conveyor the plane could move forward under propeller power, irrespective of the speed - or direction of travel - of the conveyor. In this case, the plane could move forward and take off, just as it could from an aircraft carrier.
But that is not how I read the original scenario - so I concede and lose 10 IQ points!!
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Swiss James
Joined: 26 Nov 2003
Location: Shanghai
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| Posted: Tue Dec 06, 2005 5:50 pm Post subject: |
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| hypnotist wrote: |
| huck wrote: |
| So let's say the wheels are locked - they won't spin - and there is no conveyor belt. You're saying that the thrust of the engines is strong enough to push the plane on wheels that are locked up? |
I don't quite see what this has to do with the scenario we're discussing, but for some planes I believe this is indeed the case. Some fighter jets are powerful enough to jump out of their chocks, too. |
I think it's a very similar scenario and we're saying yes- the thurst of the engines will overcome the friction of the wheels. |
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hypnotist
Joined: 04 Dec 2004
Location: I wish I were a sock
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| Posted: Tue Dec 06, 2005 5:55 pm Post subject: |
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| Wangja wrote: |
Every time I post on this thread I feel as if I am losing one IQ point.
I understand the logic that as there is no connection between the wheels (which are free to revolve and independent of the thrust) and the conveyor the plane could move forward under propeller power, irrespective of the speed - or direction of travel - of the conveyor. In this case, the plane could move forward and take off, just as it could from an aircraft carrier.
But that is not how I read the original scenario - so I concede and lose 10 IQ points!!
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Then my work here is done, and I can leave Korea a happy man One and a half weeks to go...
I'm still intrigued as to how you did read the original scenario though! |
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Wangja
Joined: 17 May 2004
Location: Seoul, Yongsan
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| Posted: Tue Dec 06, 2005 5:58 pm Post subject: |
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| hypnotist wrote: |
Then my work here is done, and I can leave Korea a happy man One and a half weeks to go...
I'm still intrigued as to how you did read the original scenario though! |
W r o n g l y!
You are coming back I hope H? |
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hypnotist
Joined: 04 Dec 2004
Location: I wish I were a sock
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| Posted: Tue Dec 06, 2005 6:05 pm Post subject: |
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| Wangja wrote: |
| hypnotist wrote: |
Then my work here is done, and I can leave Korea a happy man One and a half weeks to go...
I'm still intrigued as to how you did read the original scenario though! |
W r o n g l y!
You are coming back I hope H? |
Well, I'm quitting work to go and do an MBA, and then I'm after a job in international development or similar. Having said that, it looks at least possible I'll have a Korean wife by the end of it (*gulp*) and I notice the UN has opened an ESCAP Training Center in Incheon which is right up my street, so...
To be honest, I like the country enough that it'd be difficult to keep me away - and I'd love to stay over here a few months learning Korean (and actually living in Seoul). Particularly if I'm going to end up married to a Korean. She's already said she'd be happy to support me in that case, daft girl |
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Pligganease
Joined: 14 Sep 2004
Location: The deep south...
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| Posted: Tue Dec 06, 2005 9:40 pm Post subject: |
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| hypnotist wrote: |
| ...when Pligganease had his* Damascusian conversion. The conveyor can't stop the plane moving forward. |
I'll admit it when I'm wrong...  |
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