Will the Plane Take-Off - Merged with MythBusters Show Thread

 
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Old 10-22-2007 | 03:13 PM
  #481  
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EDIT: Bad example. Never mind.

Last edited by levon1830; 10-22-2007 at 03:15 PM.
Old 10-22-2007 | 03:13 PM
  #482  
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Originally Posted by Whiskers
Ok, I see now and I agree on the following:
-The jets will cause the plane to move as fast as it would with or without the treadmill.
-If the treadmill was very long, it will take off of the treadmill.
No do not back out on this you bastard. Can you overtake a treadmill that is going as fast as you? NO so the plane can't either and if it does start to lift for whatever reason it will hit the ground.
Old 10-22-2007 | 03:14 PM
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Maybe think of it this way: A Jet Car is running down a conveyor belt. Does it just sit there if the converor has any speed to it? The jet propulsion does not have to overcome the speed of the conveyor, just the wind resistence.
Old 10-22-2007 | 03:15 PM
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Originally Posted by Whiskers
Ok, I see now and I agree on the following:
-The jets will cause the plane to move as fast as it would with or without the treadmill.
-If the treadmill was very long, it will take off of the treadmill.

Yeah I would argue that the treadmill would have to be as long if not longer than a regular runway, the plane still has to get up to speed the physics of the plane getting into the air hasn't changed...


because the treadmill is fixed to the ground, and the plane is moving through space (air) using space (air) it's not really a fair contest between the two.
Old 10-22-2007 | 03:15 PM
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Originally Posted by JJ4Short
No do not back out on this you bastard. Can you overtake a treadmill that is going as fast as you? NO so the plane can't either and if it does start to lift for whatever reason it will hit the ground.

You use your legs to move forward. A plane uses a jet engine.

they are TOTALLY different.

explain to me how those are acceptable comparisons?
Old 10-22-2007 | 03:16 PM
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Originally Posted by JJ4Short
From what I read in the original post the treadmill will constantly match the planes speed so its not moving!

I don't know why I am getting so bent up but its crazy to me!
Thats right. But since the plane doesn't depend on the wheels for foward motion, it doesn't matter.
Old 10-22-2007 | 03:18 PM
  #487  
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Originally Posted by JJ4Short
No do not back out on this you bastard. Can you overtake a treadmill that is going as fast as you? NO so the plane can't either and if it does start to lift for whatever reason it will hit the ground.
They are saying that it doesn't matter that the treadmill is going backwards....They are saying to pretend that Luke's Land Cruiser in on a treadmill...The threadmill can be going 1,000,000 mph, but if the jets fire on the Land Cruiser, it will go forward....
Old 10-22-2007 | 03:18 PM
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Originally Posted by levon1830
Think about this question: can a powerful jetski--let's assume the 2007 Sea-Doo RXT with its 215 hp supercharged engine--travel upstream in a fast-moving river?

If the stream is just as fast as the jetski No, its impossible.

I believe the plane might start lifting up because of natural air blowing by eventually but it will fall on its belly.

Why do you guys keep saying "The plane is not going the speed of the wheels" Yes it is, if the wheels aren't going anywhere the plane is standing still. if you kick it the jets unless they are some powerful jets the planes not going anywhere.

If the plane could leave the treadmill we would only need runways for landing. The plane is not moving...the end therefore its up to the thrust of the jets, now if the thrust of the jets can make it take off without use of the runway then you have a fucking fast jet.
Old 10-22-2007 | 03:19 PM
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Why take up so much space at airports with half mile runways if a plane could launch stationary on a big treadmill?

Its because it's not possible. As the engines try to propel the plane foward, the treadmill is pulling it back, so think of it this way.......if the plane's engines were shut off, the plane would move backwards being pulled by the treadmill......turn them on and the engines are only countering the effects of the treadmill to keep it in place. As long as the treadmill is going to match the speed of the plane in the opposite way, the plane will not take off.
Old 10-22-2007 | 03:20 PM
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Originally Posted by Smalls
Thats right. But since the plane doesn't depend on the wheels for foward motion, it doesn't matter.
The plane does not achieve forward motion via force applied to the ground through its wheels. The wheels are on a plane to make it easier to achieve forward motion with a less powerful engine.
Old 10-22-2007 | 03:20 PM
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Originally Posted by cibs
Yeah I would argue that the treadmill would have to be as long if not longer than a regular runway, the plane still has to get up to speed the physics of the plane getting into the air hasn't changed...


because the treadmill is fixed to the ground, and the plane is moving through space (air) using space (air) it's not really a fair contest between the two.
There would be some resistance between the wheels and the treadmill....
Old 10-22-2007 | 03:21 PM
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Originally Posted by JJ4Short
If the stream is just as fast as the jetski No, its impossible.

I believe the plane might start lifting up because of natural air blowing by eventually but it will fall on its belly.

Why do you guys keep saying "The plane is not going the speed of the wheels" Yes it is, if the wheels aren't going anywhere the plane is standing still. if you kick it the jets unless they are some powerful jets the planes not going anywhere.

If the plane could leave the treadmill we would only need runways for landing. The plane is not moving...the end therefore its up to the thrust of the jets, now if the thrust of the jets can make it take off without use of the runway then you have a fucking fast jet.
Ignore my jetski analogy. That was a bad one.
Old 10-22-2007 | 03:22 PM
  #493  
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Originally Posted by cibs
You use your legs to move forward. A plane uses a jet engine.

they are TOTALLY different.

explain to me how those are acceptable comparisons?

The plain is not moving through "space" until it has enough lift to lift itself off the ground. What does it need to do this? LIFT, what makes lift? Wind going under the wings. How do you make wind go under the wings...move it down the runway. What happens if it is not moving down the runway? No Lift...therefore it is not in the air...there for it might lift a little from the jets but fall right on its belly.

UNLESS said Jets are strong enough to have the plane take off from standstill.
Old 10-22-2007 | 03:22 PM
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Originally Posted by JJ4Short
If the stream is just as fast as the jetski No, its impossible.

I believe the plane might start lifting up because of natural air blowing by eventually but it will fall on its belly.

Why do you guys keep saying "The plane is not going the speed of the wheels" Yes it is, if the wheels aren't going anywhere the plane is standing still. if you kick it the jets unless they are some powerful jets the planes not going anywhere.

If the plane could leave the treadmill we would only need runways for landing. The plane is not moving...the end therefore its up to the thrust of the jets, now if the thrust of the jets can make it take off without use of the runway then you have a fucking fast jet.


You still never addressed the holding a rope while on rollerblades on a treadmill scenario.

the plane does not go the speed of the wheels if it's on a treadmill. speed is relative to space right? to other landmarks on the ground.

Let's try this - you're wearing rollerblades on a treadmill holding onto a rope fastened to the wall infront of you. the treadmill is set to it's highest speed...

So the wheels on the rollerblades are moving at say 10mph... according to your argument because the wheels are moving at 10mph you are too?
Old 10-22-2007 | 03:24 PM
  #495  
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Originally Posted by JJ4Short
The plain is not moving through "space" until it has enough lift to lift itself off the ground. What does it need to do this? LIFT, what makes lift? Wind going under the wings. How do you make wind go under the wings...move it down the runway. What happens if it is not moving down the runway? No Lift...therefore it is not in the air...there for it might lift a little from the jets but fall right on its belly.

UNLESS said Jets are strong enough to have the plane take off from standstill.

EVERYTHING moves through space when moving. when it lifts off the ground it's still moving through space except now instead of moving in a linear fashion bound by gravity it's moving up away from gravity as well as forwards.


and the air from the jets would not lift the jet up at all if the scenario you pose would be true... would never happen
Old 10-22-2007 | 03:24 PM
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Originally Posted by levon1830
The plane does not achieve forward motion via force applied to the ground through its wheels. The wheels are on a plane to make it easier to achieve forward motion with a less powerful engine.
No but it needs its wheels to move. If you are pushing the wheels backwards and the plane is sitting in one spot, the plane will not take off and if it does it will crash. Sorry. Jets are not strong enough to go from a dead stop, unless they built some and put it on the plane.
Old 10-22-2007 | 03:24 PM
  #497  
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Originally Posted by JJ4Short
The plain is not moving through "space" until it has enough lift to lift itself off the ground. What does it need to do this? LIFT, what makes lift? Wind going under the wings. How do you make wind go under the wings...move it down the runway. What happens if it is not moving down the runway? No Lift...therefore it is not in the air...there for it might lift a little from the jets but fall right on its belly.

UNLESS said Jets are strong enough to have the plane take off from standstill.
You and I are in space right now as we sit in front of our computers typing responses to this thread. You do not have to be in the air to be considered 'in space.'
Old 10-22-2007 | 03:24 PM
  #498  
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Originally Posted by JJ4Short
No do not back out on this you bastard. Can you overtake a treadmill that is going as fast as you? NO so the plane can't either and if it does start to lift for whatever reason it will hit the ground.

You move on the treadmill by pushing off against the ground. Your forward speed is directly related and effected by the movement of the ground. So if the ground is moving backwards you have to push twice as hard. The difference here is that a plane pushes against the air to move forward, and the treadmill moving underneath wont change that.

If the AIR was moving backwards (lets say a very strong wind) then that might prevent it from moving forward.
Old 10-22-2007 | 03:24 PM
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Winter ban games. JJ and whiskers get my nomination.
Old 10-22-2007 | 03:24 PM
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Originally Posted by JJ4Short
The plain is not moving through "space" until it has enough lift to lift itself off the ground. What does it need to do this? LIFT, what makes lift? Wind going under the wings. How do you make wind go under the wings...move it down the runway. What happens if it is not moving down the runway? No Lift...therefore it is not in the air...there for it might lift a little from the jets but fall right on its belly.

UNLESS said Jets are strong enough to have the plane take off from standstill.
Again, the assumption here is that the plane is moving forward as fast as it would on a normal surface......Again, think of a whole runway that is a treadmill and realize that the plane will travel the entire length of the runway (or at least as long as it takes for liftoff)..
Old 10-22-2007 | 03:25 PM
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Fuck it who wants to put money on it! I am serious that bitch ain't going nowhere!
Old 10-22-2007 | 03:26 PM
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Originally Posted by salvo24
Why take up so much space at airports with half mile runways if a plane could launch stationary on a big treadmill?

The planes have to land somewhere..
Old 10-22-2007 | 03:26 PM
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Originally Posted by dom
Winter ban games. JJ and whiskers get my nomination.
No...I swiched sides last page...
Old 10-22-2007 | 03:27 PM
  #504  
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http://txfx.net/2005/12/08/airplane-on-a-conveyor-belt/

When an airplane takes off, there is one major forward force… the forward thrust. The main rearward force is air resistance. The turning of the wheels provides a small frictional force, but because the wheels are free-rolling, this friction is very small. Unless the wheels are locked, the friction is always going to be less than the thrust, which means that the overall force is still forward, and the plane will still move.

Gah… people are freakin’ stupid.
Old 10-22-2007 | 03:28 PM
  #505  
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Was my jet car analogy a bad one or something? Doesn't that help clear it up?
Old 10-22-2007 | 03:28 PM
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Originally Posted by levon1830
The plane does not achieve forward motion via force applied to the ground through its wheels. The wheels are on a plane to make it easier to achieve forward motion with a less powerful engine.

oh i agree. the plane does not stay stationary.
Old 10-22-2007 | 03:28 PM
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BTW what kind of plane are we talking about?

Big difference between an A810 and an F16
Old 10-22-2007 | 03:29 PM
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Originally Posted by JJ4Short
BTW what kind of plane are we talking about?

Big difference between an A810 and an F16
Doesn't matter
Old 10-22-2007 | 03:30 PM
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Originally Posted by dom
http://txfx.net/2005/12/08/airplane-on-a-conveyor-belt/

When an airplane takes off, there is one major forward force… the forward thrust. The main rearward force is air resistance. The turning of the wheels provides a small frictional force, but because the wheels are free-rolling, this friction is very small. Unless the wheels are locked, the friction is always going to be less than the thrust, which means that the overall force is still forward, and the plane will still move.

Gah… people are freakin’ stupid.

Nice link, has the most complete explanation I've read so far, with examples and everything. If after reading that you don't get it then I'll take your money JJ. Given that mythbusters tests it properly.
Old 10-22-2007 | 03:30 PM
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Originally Posted by JJ4Short
BTW what kind of plane are we talking about?

Big difference between an A810 and an F16
Its a KFC820....
Old 10-22-2007 | 03:30 PM
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Hmm I am starting to rethink this...how powerful are jet engines at full thrust...someone get back to me on this...NO bets fuck you guys No bans either DOM rich Canadian bastard and by bastard I mean super great guy.
Old 10-22-2007 | 03:31 PM
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aggggh this is killing me. If the plane can overcome the threadmill (assuming it's infinite is size) than it breaks the assumption that the threadmill can match the planes speed.
Old 10-22-2007 | 03:31 PM
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Originally Posted by Smalls
oh i agree. the plane does not stay stationary.
Yeah, I know. I was just trying to clear things up for those who still think the plane achieves forward motion via energy applied to the earth (or runway, or conveyor belt) via its wheels.
Old 10-22-2007 | 03:32 PM
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Originally Posted by JJ4Short
Hmm I am starting to rethink this...how powerful are jet engines at full thrust...someone get back to me on this...NO bets fuck you guys No bans either DOM rich Canadian bastard and by bastard I mean super great guy.

It would depend on the engine. But you'd have to assume that the engine on any given plane is enough to make it fly. If that isn't the case it wouldn't be a plane it would be a hunk of metal with some engines that push it around.

This scenario calls for a plane.
Old 10-22-2007 | 03:32 PM
  #515  
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Originally Posted by Whiskers
Its a KFC820....
Well when we drop in the deliciousness factor then its a whole different ball game.
Old 10-22-2007 | 03:33 PM
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Originally Posted by AQUI NO!
aggggh this is killing me. If the plane can overcome the threadmill (assuming it's infinite is size) than it breaks the assumption that the threadmill can match the planes speed.

the treadmill can go 5 times faster than the plane if it wants... the plane will still take off....
Old 10-22-2007 | 03:33 PM
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The only thing that would change this would be if the wheels seized / blew up...
Old 10-22-2007 | 03:40 PM
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http://www.meignorant.com/plane_Moz

Ok a canadian explained it.
Old 10-22-2007 | 03:40 PM
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Originally Posted by Whiskers
No...I swiched sides last page...

Good job converting. I used to think it wouldn't take off either. Notice how people switch from "not taking off" to "taking off" but not vice versa. . .
Old 10-22-2007 | 03:42 PM
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Originally Posted by Whiskers
No...I swiched sides last page...



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