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 Message Boards » » so a plane takes off from a treadmill.... Page 1 2 3 4 [5] 6 7 8 9 10 11, Prev Next  
tchenku
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11/19/2007 9:39:27 AM

benz240
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^^ there is negligible resistance to motion by the wheels

and once again, A TREADMILL IS IRRELEVANT TO PLANES

[Edited on November 19, 2007 at 9:40 AM. Reason : ]

11/19/2007 9:39:42 AM

baonest
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now its an official page 5.

page 4 is not officials.
official stamp---\/



[Edited on November 19, 2007 at 9:44 AM. Reason : ]

11/19/2007 9:44:05 AM

benz240
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^ haha shit is funnier each time i read it

11/19/2007 9:46:05 AM

humandrive
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I see the .gif of the kid with the wheels. The problem is she is not on a treadmill so it is worthless.

11/19/2007 10:15:07 AM

ScHpEnXeL
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because that matters and all

11/19/2007 10:16:42 AM

humandrive
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the treadmill seems very important to this plane problem

11/19/2007 10:19:11 AM

tchenku
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the Heelys pic is just for fun

Do you think the plane will take off faster with the treadmill going in the same direction? Because it won't. Basically, treat it like the plane is on a frictionless surface with likewise zero friction in its wheels and wheel bearings

[Edited on November 19, 2007 at 10:52 AM. Reason : ]

11/19/2007 10:51:54 AM

ScHpEnXeL
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yeah, without friction, the conveyor does nothing.. and since the plane has wheels, there is not enough friction to matter.. thus, ignore the conveyor, plane takes off, stfu

11/19/2007 10:53:44 AM

Wyloch
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How did this thread reach 5 pages?

The plane does not take off.

/thread

11/19/2007 12:04:27 PM

ScHpEnXeL
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troll

11/19/2007 12:05:02 PM

Wyloch
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Ah. I see.

11/19/2007 12:07:39 PM

Jen
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my pick of best tww threads

dont know if the damn thing takes of or not but it sure is funny that ppl are still fighting bout it

11/19/2007 12:13:14 PM

Wraith
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Hahaha this thread causes so many carl faces.

First of all:
Quote :
" if it does, it's because the props generated airspeed over the wings"

lol

I hope you know that if this worked, it would be a totally new way of hovering.

Second:
I'm really kind of interested as to how exactly the Mythbusters are going to set this up. For one, they are going to need an extremely large treadmill and a plane with an extremely short take off distance. And even if they build/acquire this treadmill, how are they going to get it to match speed with the plane constantly? Very tricky set up. I kind of get the feeling that they aren't going to be able to replicate enough ideal variables to get proper results.

Third:
Let's say that instead of wheels/treadmill, the situation is ice skates and a giant sheet of moving , freshley zambonied ice. It would probably be easier for you to understand since ice is generally easier to see as being as close to frictionless as practically possible. So say you are on this sheet of ice with your skates and it starts moving fast. Because it is FRICTIONLESS, you are going to stay still. It is frictionless, therefore there is NO force acting on you in the X-direction. So now someone throws a rope to you and you pick up the rope. Still no force acting on you in the X-direction cause it is frictionless. So now you start pulling yourself forward. The ice has no effect on the skates because it is frictionless. The only force on you in the X-direction is the tension caused by you pulling yourself forward. So now instead of you on the ice, it is a plane with giant ice skates for a landing gear and a bunch of guys pulling it. Same thing happens. So now instead of guys pulling, it is a jet pushing or a prop pulling. It still goes forward. I think the thing most people seem to have trouble with is understanding that it is gonna move forward.

[Edited on November 19, 2007 at 12:27 PM. Reason : ]

11/19/2007 12:26:58 PM

Wyloch
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^ I thought the myth specified that the treadmill will move at the same speed as the wheels.

When on the ground, the plane will not move unless the wheels can create net horiz. distance. If the treadmill constantly adjusts, how will the plane move?

11/19/2007 12:30:07 PM

CapnObvious
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I think I finally understand what you "The plane will take off" guys are talking about. And let me just say, you are wrong (I am sure that you will correct me if I am wrong ).

You are saying that the engines are propelling the plane on the treadmill. The wheels are merely a medium to slide accross the ground and have nothing to with the actual movement of the plane. Therefore, with the engines pushing, the plane will move forward as normal, the wheels will spin twice as fast in the opposite direction, and the plane will take off as planned. Do I understand you correctly?

If so, then you are wrong. The problem is that the myth implies that the plane is not actually moving because it is on a treadmill (hence why the treadmill is involved). You keep saying that the treadmill doesn't matter, but it is the KEY part of this myth. I suppose it is more of a question if a plane can "accelerate" is one place then start ascending without actually moving anywhere.

If you can get into a position where the plane is "working" on the treadmill but not actually moving anywhere, as the original premise of the myth dictates, then the plane will not take off. Seems pretty obvious to me. It is not moving with respect to the air around it, and therefore cannot fly.

If we are to assume that the treadmill doesn't actually matter and the plane will move forward as planned, then the entire premise of this myth is null because it can never happen. It WILL NOT take off because this is an invalid scenario. So, for those of you saying it will take off, you are still wrong.

Thanks for playing. Let me know if I messed up any of your logic for how you expect this myth to occur.

[Edited on November 19, 2007 at 12:38 PM. Reason : .]

11/19/2007 12:36:55 PM

Wyloch
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^ Correct.

11/19/2007 12:37:43 PM

Wyloch
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Of course MythBusters will probably screw this up as usual by not putting their model on a variable speed treadmill.

I remember once they were baffled because a steel cable rated at 5,000 pounds kept snapping when tied to a car traveling double digit mph. "But the car only weighs 3,000 pounds, so we don't know why the cable is snapping." I hate that show.

[Edited on November 19, 2007 at 12:43 PM. Reason : ]

11/19/2007 12:43:12 PM

Wraith
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How is the treadmill stopping the plane from moving?

11/19/2007 2:19:03 PM

Doss2k
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Wow... I cant believe people are still arguing it wouldnt take off

11/19/2007 2:49:07 PM

Smath74
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Quote :
"I think I finally understand what you "The plane will take off" guys are talking about. And let me just say, you are wrong (I am sure that you will correct me if I am wrong ).

You are saying that the engines are propelling the plane on the treadmill. The wheels are merely a medium to slide accross the ground and have nothing to with the actual movement of the plane. Therefore, with the engines pushing, the plane will move forward as normal, the wheels will spin twice as fast in the opposite direction, and the plane will take off as planned. Do I understand you correctly?

If so, then you are wrong. The problem is that the myth implies that the plane is not actually moving because it is on a treadmill (hence why the treadmill is involved). You keep saying that the treadmill doesn't matter, but it is the KEY part of this myth. I suppose it is more of a question if a plane can "accelerate" is one place then start ascending without actually moving anywhere.

If you can get into a position where the plane is "working" on the treadmill but not actually moving anywhere, as the original premise of the myth dictates, then the plane will not take off. Seems pretty obvious to me. It is not moving with respect to the air around it, and therefore cannot fly.

If we are to assume that the treadmill doesn't actually matter and the plane will move forward as planned, then the entire premise of this myth is null because it can never happen. It WILL NOT take off because this is an invalid scenario. So, for those of you saying it will take off, you are still wrong.

Thanks for playing. Let me know if I messed up any of your logic for how you expect this myth to occur."


of course if the plane isn't moving it won't take off.

but that is not what the original myth dictates. it says that the treadmill will move the same speed but in the opposite direction as the plane.

this means that if the plane was not moving, neither would the treadmill.

if the treadmill was moving 300mph east, then the plane would HAVE to be moving 300 mph west, and therefore it would be moving relative to the air and it would fly. (there would be a total difference of 600mph between the plane and the treadmill.)

11/19/2007 2:51:32 PM

Skack
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It would be funny to reverse the treadmill right as the plane is trying to take off and watch it sling it off the runway.

11/19/2007 3:03:00 PM

moron
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^ Huh? that wouldn't happen either.

11/19/2007 3:05:08 PM

bbehe
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11/19/2007 3:08:05 PM

Aficionado
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Quote :
"It would be funny to reverse the treadmill right as the plane is trying to take off and watch it sling it off the runway."


inertia

11/19/2007 3:11:33 PM

Arab13
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planes don't "work" on the ground.... cars do

Quote :
"Therefore, with the engines pushing, the plane will move forward as normal, the wheels will spin twice as fast in the opposite direction, and the plane will take off as planned."


yes, ground speed =! airspeed, planes need a certain amount of airspeed to fly

Quote :
"It would be funny to reverse the treadmill right as the plane is trying to take off and watch it sling it off the runway."


it would be funny, b/c it wouldn't do anything

(technically there is some friction involved here, but it's negligible

[Edited on November 19, 2007 at 3:16 PM. Reason : s]

11/19/2007 3:13:58 PM

ScHpEnXeL
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Do you guys really not get it that treadmill does nothing to change the planes velocity in relation to air speed? That is all the matters here, the plane will absolutely take off and I can't tell if you guys are just trolling or if you seriously think it won't. The plane is still going to move down the runway no matter how fast the ground is moving. The air is not connected to the ground and the plane's speed relative to the air it is going through will still be high enough for the plane to take off, period.

Quote :
"The problem is that the myth implies that the plane is not actually moving because it is on a treadmill (hence why the treadmill is involved)."


No, the myth is saying if you're a dumbass, that's what you'll assume and thus conclude that it doesn't take off. That isn't what would happen though

edit: There's gotta be able to do this with a really long treadmill and an RC plane just to prove this shit..

[Edited on November 19, 2007 at 3:16 PM. Reason : asdf]

11/19/2007 3:15:14 PM

mdozer73
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This thread is funny.

Lets say they set up the treadmill to run 10 mph.

The plane is on the treadmill as they turn it on. The wheels of the plane start turning at 10 mph but the plane isnt moving.

Lets assume the plane needs 100 mph to take-off.

The plane starts to accelerate it's engines and begins to move forward. The propulsion of the plane is against the air around it, not the ground so every mph the plane accelerates the wheels are turning 10 mph faster.

Right before takeoff, the plane's wheels are turning 110 mph due to the treadmill, but the plane is only moving 100 mph.

Then it takes off.

The End!

BTW: The treadmill will have to be as long as a runway, or atleast long enough for whatever type of plane they use to takeoff.

[Edited on November 19, 2007 at 3:19 PM. Reason : mo]

11/19/2007 3:16:36 PM

Arab13
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^^ yeah, that's what i was thinking about how they would do it

[Edited on November 19, 2007 at 3:17 PM. Reason : 3]

11/19/2007 3:17:01 PM

Wyloch
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...I think I finally understand.

Yeah, it would take off.

For those still thinking it wouldn't: if you had a constant wind blowing against the plane at a speed equal that which would be produced by the engines, it would still take off, but to a ground observer it would appear to have no horizontal motion...and that would be a freakin' sight...

11/19/2007 3:26:02 PM

Doss2k
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It's pretty simple you just have to consider where the forward movement is being generated. If it were a car or a bike or a person on the treadmill then yes they would stand still. The wheels are simply there to turn and cancel out most of the friction as the engines provide the movement speed. The people who claim it wont take off are assuming that the forward speed of the plane is being driven by the wheels in which case they would be correct, last i checked though if that were the case as soon as the plane came off the groud its forward movement would stop along with the plane and hence come back to earth very quickly.

11/19/2007 3:27:40 PM

NutGrass
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mythbusters is going to use an ultra light plane for this experiment. the pilot and crew were all wrong on their predictions on what would happen.

11/19/2007 4:05:50 PM

Wyloch
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I feel like a failed engineer for ever being wrong on this one.

11/19/2007 4:17:38 PM

hondaguy
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Quote :
"I feel like a failed engineer for ever being wrong on this one."


good, you should

11/19/2007 4:46:10 PM

69
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^

11/19/2007 6:51:07 PM

XSMP
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ok - the plane would not take off, if the treadmill was canceling out the plane's forward movement.
the plane would* take off if the treadmill was assisting the plane in moving forward, however that
is a big god damn treadmill.

bottom line here is aerodynamics. if the plane is stationary, it isn't going anywhere.
/thread

11/19/2007 7:34:34 PM

Smath74
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how the fuck would the treadmill hold the plane stationary? mofo has jet fucking engines.

11/19/2007 7:39:00 PM

damosyangsta
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TWW: discovering old-ass internet memes for the first time.

11/19/2007 7:42:21 PM

humandrive
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It can't take off the treadmill is making sure the wind speed over the wings at zero

11/19/2007 7:43:14 PM

XSMP
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here's an analogy for ya - pretend that one treadmill works as a dyno (like for car performance testing)
the other is like the walkways in the airport that help you get across the terminal faster.

11/19/2007 7:46:56 PM

damosyangsta
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Why do they even test myths like this? Simple common sense could prove it wrong.

11/19/2007 7:49:11 PM

Beckers
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Lift is generated by the movement of air over the airfoils...if there is no forward movement of the plane then the air is not being moved over the airfoil and lift cannot be generated. End of Story.

11/19/2007 7:50:30 PM

XSMP
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i said that 7 posts ago

11/19/2007 7:51:12 PM

Beckers
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haha...yeah...
but don't make me break out my Lift equation

11/19/2007 7:59:04 PM

XSMP
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im
not
beckers

11/19/2007 8:01:58 PM

ScHpEnXeL
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Quote :
"Lift is generated by the movement of air over the airfoils...if there is no forward movement of the plane then the air is not being moved over the airfoil and lift cannot be generated. End of Story."


the whole point is the treadmill isn't going to stop it from moving forward relative to the air that is still stationary, you can essentially roll the wheels whatever way you want to, it isn't changing the air speed relative to the wings

11/19/2007 8:28:59 PM

ScHpEnXeL
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Quote :
"It can't take off the treadmill is making sure the wind speed over the wings at zero"


yea, because we all know that treadmills are made to move a bunch of air

11/19/2007 8:29:41 PM

ScHpEnXeL
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Quote :
"here's an analogy for ya - pretend that one treadmill works as a dyno (like for car performance testing)
the other is like the walkways in the airport that help you get across the terminal faster.

"


for the dyno analogy, you have to realize a planes wheels roll freely and have absolutely nothing to do with its movement in any direction. as for the airport walkways, imagine being on them with roller skates and being pulled by someone with a rope that isn't on the moving walkway... you can still move freely

11/19/2007 8:35:33 PM

Wyloch
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If the treadmill is moving at 100% of takeoff speed, the plane will move forward.

It the treadmill is moving at 1000% of takeoff speed, the plane will move forward.

It the treadmill is moving at 10000% of takeoff speed, the plane will still...move forward.

11/19/2007 9:53:51 PM

ScHpEnXeL
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Thank God somebody gets it

11/19/2007 9:55:04 PM

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