Quote :

"The myth is whether the plane can take off if its remaining at a standstill with engines at full throttle."

but that would never happen. if the engines are at full thrust then the plane will move forward no matter how fast the treadmill is going. it will not remain stationary!!!

1/29/2008 12:08:13 PM

[Edited on January 29, 2008 at 12:12 PM. Reason : .]

1/29/2008 12:12:21 PM

there's a whole lot of stupid in this thread.

1/29/2008 12:12:35 PM

Quote :

"but that would never happen. if the engines are at full thrust then the plane will move forward no matter how fast the treadmill is going. it will not remain stationary!!! "

Duder

I'm going to assume, for the sake of my faith in the American College system, that you are joking.

1/29/2008 12:15:47 PM

that is of course neglecting frictional forces from the bearing in the wheels...that will be the only limitation. take it from an engineer....but in case you don't believe me here is the mr rogers explanation for you





[Edited on January 29, 2008 at 12:27 PM. Reason : ...]

1/29/2008 12:23:58 PM

Uhhhhhhhhhhhhhhhhhhh

If you look at his experiment, his plane accelerates regardless of the treadmill speed because he's providing thrust independent of the of the force at the wheels.

This falls under the "uninteresting myth" that I defined earlier. Nobody should logically argue that a plane can't accelerate to flight OFF a treadmill.

This is almost an inverse of the experiment where a car going 60mph can drive up a ramp into a 18 wheeler and come to a complete stop almost instantly.

The argument I'll make is that if the treadmill were to match the acceleration of any object on it then that object would stay stationary. This is why when you start walking, or running, on a treadmill you don't run off. Stationary objects don't provide lift, and with no lift a plane won't take off.

1/29/2008 12:37:36 PM

Quote :

"If you look at his experiment, his plane accelerates regardless of the treadmill speed because he's providing thrust independent of the of the force at the wheels."

TA DAAAAAAAAAAA....you just solved the myth. that's how all planes work. thrust is provided by either a prop or a jet engine...not the wheels

anyway....the original myth states a treadmill of infinite length

Quote :

"The argument I'll make is that if the treadmill were to match the acceleration of any object on it then that object would stay stationary. This is why when you start walking, or running, on a treadmill you don't run off. Stationary objects don't provide lift, and with no lift a plane won't take off."

did you even watch the video? I will state again...THE PLANE MOVES FORWARD...I.E. NOT STATIONARY!!


[Edited on January 29, 2008 at 12:44 PM. Reason : UGH]

1/29/2008 12:38:44 PM

then the engines wouldn't even need to be on except to overcome a little inertial friction

1/29/2008 12:39:31 PM

Sandsanta,

The treadmill cannot possibly stop the plane from moving unless the wheels stop turning and become locked to the airplane (hitting the brakes), or the treadmill goes so fast that the friction in the wheels becomes high enough to melt them off of the plane, in which case, you are right the plane will never take off because as soon as it becomes locked to the treadmill, it will be thrown off into a fiery mass of dead people.

The only transferrance of force from the treadmill to the airplane occurs via the friction in the wheel bearings. If you think that friction can overcome the thrust of a jet engine, you are wrong.


Signed,

Reality.

1/29/2008 12:44:39 PM

sparky im sorry but you're either trying to troll or you're essentially one really dumb kid.

Quote :

" that's how all planes work. thrust is provided by either a prop or a jet engine...not the wheels\ "

No wai! That's never been any issue as far as what I've argued. I've always maintained that if the acceleration of the treadmill matches the acceleration of the god damn plane it won't take off.

Why? Because it remains stationary.

Whats that mean?

Lift, the mechanism that allows flight, won't happen as there won't be air moving over and under the wings.

Quote :

" did you even watch the video? I will state again...THE PLANE MOVES FORWARD...I.E. NOT STATIONARY!! "

Revoke your god damn engineering degree. Just hand that in right now. Seriously. Avoid english as well since you can't read and avoid science as you clearly don't know what a controlled experiment is.

The acceleration of the treadmill at no point matches the acceleration of the plane so naturally the god damn thing can move forward.

I can prove this concept to you in five minutes at the NC State gym. Get on the treadmill, and ill speed it up, you tell me how much directional velocity you have if you actively match the acceleration of the belt.

[Edited on January 29, 2008 at 12:49 PM. Reason : I mean the guy's own math proves this, even though when he realized it he was like "uhhh anyway"]

1/29/2008 12:47:18 PM

^ are you that stupid?
It doesn't matter if the treadmill matches the acceleration of the plane. The only force is the wheels spinning freely. The treadmill could acclerate 1000000000x faster than the plane, and it will still take off, because the wheels spin freely, and the only acting forces on the plane is thrust and gravity esentially.

It will take off regardless of speed or acceleration of the treadmill.

1/29/2008 12:51:44 PM

please tell me how a treadmill will do anything to the plane with jet engines on except cause the wheels to rotate twice as fast?


it won't. the plane will move forward at 300 mph just as the treadmill is moving backwards at 300 mph.

the wheels will rotate at the equivilant of 600 mph.





now, if you claim the plane is stationary, then the treadmill MUST be stationary as well, if it moves the same speed as the plane in the opposite direction.

1/29/2008 12:53:57 PM

^^^damn you are an idiot. do you really think a pilot will only use say 10% of a planes engine thrust to take off?? no...they go full throttle. i see what you are saying...if the plane is not moving relative to the air or ground around it (not the treadmill) then it won't take off....just as the video demonstrated. did you see where he had the plane at partial thrust keeping it stationary no matter the speed of the treadmill? however when he went full thrust the plane moved forward. given a long enough treadmill and enough thrust the plane will take off. the treadmill is insignificant. can i please please put you on a treadmill with roller skates and strap and jet engine to you and see if you move forward??

[Edited on January 29, 2008 at 12:56 PM. Reason : ^^^]

1/29/2008 12:55:45 PM

^^wow

[Edited on January 29, 2008 at 1:01 PM. Reason : idiot or troll, you decide]

1/29/2008 12:59:33 PM

Quote :

"It doesn't matter if the treadmill matches the acceleration of the plane. The only force is the wheels spinning freely. "

Ok let me slow it down because you guys are clearly not seeing this.

When you're on a treadmill and your speed matches the speed of the belt, you are stationary. This not argued fact.

In the guys experiment, he sped the belt up to max, and then applied thrust. The object accelerated. Again, yes, overcoming the counterforce and moving forward. No magic there either.

However, if the belts acceleration matches the acceleration provided by thrust, then the wheels are in essence, spinning freely and the object remains stationary. It doesn't move forward, or back, it just stays.

Again, come with me to a gym and bring yourself or a remote control car and we can easily simulate this.

Quote :

" The treadmill could acclerate 1000000000x faster than the plane, and it will still take off, "

No, it would actually get thrown off the belt due to the force of friction.

Quote :

" damn you are an idiot. do you really think a pilot will only use say 10% of a planes engine thrust to take off?? no...they go full throttle. i see what you are saying...if the plane is not moving relative to the air or ground around it (not the treadmill) then it won't take off....just as the video demonstrated. did you see where he had the plane at partial thrust keeping it stationary no matter the speed of the treadmill? however when he went full thrust the plane moved forward. given a long enough treadmill and enough thrust the plane will take off. the treadmill is insignificant. can i please please put you on a treadmill with roller skates and strap and jet engine to you and see if you move forward?? "

What you fail to grasp, along with every other "engineer" continuing this retarded debate is that the speed of the belt was set when he went "full throttle". If the belt accelerated to parity with the increase in thrust, then forces would cancel out and the plane would again remain stationary.

1/29/2008 1:02:27 PM

Quote :

"When you're on a treadmill and your speed matches the speed of the belt, you are stationary. This not argued fact."

If you are transferring force between the treadmill and yourself, this is true. (Like walking on a treadmill).

There is almost zero transfer of forces between the plane and the treadmill.

The engines are transferring force to the air, not the treadmill.

1/29/2008 1:06:53 PM

Quote :

"Again, come with me to a gym and bring yourself or a remote control car and we can easily simulate this."

nigga said bring a car

1/29/2008 1:08:44 PM

Quote :

"No, it would actually get thrown off the belt due to the force of friction."

negative, it has wheels yes? ever see a table cloth yanked off and all the stuff stay on? that's the only effect that the plane would have that's influenced at all by the belt, the wheels will just spin like crazy, it would take minimal thrust to keep it stationary (over coming the tiny bit of friction in the imperfect wheels). at full thrust the plane would accelerate the air (no force transfered or connected in anyway with the tread mill) with enough force to provide the adequate thrust to take off.

whether or not the wheels and the tires would destroy themselves through excessive rotational forces is a different bit all together.

if the airplane has engines at full throttle, nothing short of locking the wheel brakes or a tail wind of the same speed would keep the plane from accelerating and taking off.

this is why you can take off on: water, ice, moving objects

[Edited on January 29, 2008 at 1:12 PM. Reason : s]

1/29/2008 1:09:13 PM

Quote :

"Again, come with me to a gym and bring yourself or a remote control car and we can easily simulate this."

and here is your flaw in logic....its not a car...its a plane.

the whole reason that he increased the speed of the treadmill while keeping the thrust constant was to show that the speed of the plane is independent of the speed of the treadmill. so it doesn't matter how fast the treadmill goes, all that does is make the wheels spin faster.

[Edited on January 29, 2008 at 1:14 PM. Reason : f]

1/29/2008 1:13:06 PM

Quote :

"idiot or troll, you decide"

to this whole thread.



[Edited on January 29, 2008 at 1:22 PM. Reason : .]

1/29/2008 1:21:26 PM

I wouldn't normally be as shocked had some of the people in this thread not possessed engineering degrees.

I concede. If the plane is made of purestrain gold, it'll take off on hopes and aspirations alone.

1/29/2008 1:33:31 PM

Quote :

"I can prove this concept to you in five minutes at the NC State gym. Get on the treadmill, and ill speed it up, you tell me how much directional velocity you have if you actively match the acceleration of the belt. "

Quote :

"However, if the belts acceleration matches the acceleration provided by thrust, then the wheels are in essence, spinning freely and the object remains stationary. It doesn't move forward, or back, it just stays. Again, come with me to a gym and bring yourself or a remote control car and we can easily simulate this."

both of these sentences indicate that you're missing out on the fundamental difference between a person or car on a treadmill and a plane on a treadmill.

A person and a car are powered by legs/wheels which provide force directly on the treadmill. Therefore, you are perfectly correct in saying that if a person or car accelerates on a treadmill, then the treadmill can accelerate in the opposite direction, preventing them from moving.

But a plane generates it's forward moving force from engines that provide thrust against the air, not the treadmill. Therefore, any thrust that is provided by the engine against the air cannot be compensated for by turning the treadmill faster.

If you're hung up on the whole gym and treadmill issue, try this.
Go to the gym, but strap a rocket to your back, horizontal to the ground. Get on the treadmill and crank it up and start running. Accelerate your run, and speed up the treadmill to match it. No problem so far. Now, turn on the rocket on your back. What happens? Hopefully you smash your face in the mirror in front of the treadmill.
The rocket is providing thrust against the air that is behind you. You will agree that as soon as you ignite the rocket boosters, it doesn't matter how fast you start running or how fast the treadmill goes in the opposite direction, you're going to go flying off the front of the belt, right?

This is exactly what happens with the plane when it turns its engines on. The only difference is, instead of smashing head first into a wall because your arms don't provide you any lift, the airplane will take off when it reaches the right speed.

1/29/2008 1:38:59 PM

Ok now that it is settled...would a seaplane take off on a fast moving river? /troll

[Edited on January 29, 2008 at 1:44 PM. Reason : hahaha had to label]

1/29/2008 1:39:00 PM

I vote troll, nobody is this dumb if they've even glanced at the 50 threads about this myth.

1/29/2008 1:40:16 PM

Quote :

"When you're on a treadmill and your speed matches the speed of the belt, you are stationary. This not argued fact."

uh, if you have speed, (on a treadmill or not,) you are not stationary.

1/29/2008 1:41:52 PM

You can have speed if your reference point is you, on a treadmill.

1/29/2008 1:44:02 PM

that's not the reference point in this question. the reference point is the surrounding body of air.

1/29/2008 1:45:32 PM

Right, well in that case you don't have speed. You're stationary.

1/29/2008 1:46:01 PM

same principle scuba steve ;-)

yes it will take off!! however i would argue that it would take more thrust since the friction of the pontoons on the water is probably greater then the friction on the wheel bearings.

1/29/2008 1:46:36 PM

Quote :

"Right, well in that case you don't have speed. You're stationary."

no you are not. the force of the jet engines are pushing the plane in relation to the airmass.

1/29/2008 1:48:11 PM

NC State education at its finest.

PURESTRAIN JET ENGINES

1/29/2008 1:50:26 PM

this isn't rocket science guys

1/29/2008 1:53:36 PM

Quote :

"1. Push a treadmill with the rear of it close to a wall. The wall in this example represents the standing air around a airplane sitting on the runway. 2. Put on rollerskates (or stand on a skateboard) and get on the treadmill facing the wall. You now represent an airplane sitting on the runway. 3. Push your arms against the wall with light force. Congratulations, you have just turned the engines in the plane on. 4. Have a friend start the treadmill, while you still apply force to the wall. The treadmill is now moving. 5. To complete the experiment, have your friend change the speed of the treadmill as much as he/she wants, and use the force of your arms (engines) to move yourself forward and backward on the treadmill. Push really hard (cranking up the engines) and move yourself on the treadmill. Congratulations, if you pushed hard enough, you took off. If you have really good bearings in your skates, the force of the friction will be negligible, and you will require almost the same amount of pushing from your arms to keep you in the same spot on the treadmill regardless of the speed of the treadmill. "

1/29/2008 1:54:31 PM

see that stuff coming out of the back? the force of that stuff coming out of the back makes the plane go forward. it doesn't care what the wheels are doing unless they are unable move. (if the parking brake is on.)

1/29/2008 1:58:19 PM

i will be watching this

1/29/2008 2:00:08 PM

This myth is busted, why would someone take off on a treadmill?

1/29/2008 2:04:06 PM

....

Quote :

"this isn't rocket science guys"

1/29/2008 2:07:17 PM

I guarantee that there are going to be a lot of pissed off people on Wednesday night.

1/29/2008 2:12:10 PM

Quote :

"(if the parking brake is on.)"

[Edited on January 29, 2008 at 2:15 PM. Reason : ITS NOT ROCKET SURGERY]

1/29/2008 2:15:28 PM

http://community.discovery.com/eve/forums/a/tpc/f/9401967776/m/5841963149/p/4
will explode Wednesday night.

1/29/2008 2:15:57 PM

Quote :

" However, if the belts acceleration matches the acceleration provided by thrust, then the wheels are in essence, spinning freely and the object remains stationary. It doesn't move forward, or back, it just stays. "

Once the plane's engines are to the point where they can overcome friction, the acceleration of the treadmill is irrelevant.

The acceleration is irrelevant anyway, since the plane obviously can very easily overcome friction (if he put some wd40 or used higher quality wheels, it could probably take less thrust than in the video), but it's REALLY irrelevant once it starts moving.

1/29/2008 2:44:06 PM

i'm waiting on SandSanta's response to

Quote :

"If you're hung up on the whole gym and treadmill issue, try this. Go to the gym, but strap a rocket to your back, horizontal to the ground. Get on the treadmill and crank it up and start running. Accelerate your run, and speed up the treadmill to match it. No problem so far. Now, turn on the rocket on your back. What happens? Hopefully you smash your face in the mirror in front of the treadmill. The rocket is providing thrust against the air that is behind you. You will agree that as soon as you ignite the rocket boosters, it doesn't matter how fast you start running or how fast the treadmill goes in the opposite direction, you're going to go flying off the front of the belt, right? This is exactly what happens with the plane when it turns its engines on. The only difference is, instead of smashing head first into a wall because your arms don't provide you any lift, the airplane will take off when it reaches the right speed."

i'm picturing him thinking really hard and then a sudden dawning, a realization, epiphany! then him slinking away and pretending like he never posted in here

1/29/2008 2:58:32 PM

I don't think sandsanta is going to be too thrilled to strap a rocket to his back OR smash his head in to a wall.

1/29/2008 3:11:10 PM

still no cure for cancer

1/29/2008 3:24:05 PM

I can't believe this is so difficult to understand... for what seems to be a lot of engineers.

Those who said the plane will not take off are correct. Ultimately, the only way the plane is going to take off is when sufficient lift is generated, and at least it appears that everyone agrees on that.

Let's say that the plane needs to hit 100mph ground speed (made up number, not important) to take off. Motion and speed are always relative. If that 100mph speed is with a 0mph tailwind, then with a 1mph tailwind, your ground speed would need to be 101mph. If you had a 1mph headwind, then you could take off at 99mph.

So, if the treadmill is moving in the opposite direction of the plane at equal speed, then the plane's motion relative to the ground is 0. If there is no head or tailwind, then the air's speed relative to the ground is also 0. Therefore there's no way to generate lift in this situation.

Now if you add a 100mph headwind, then the plane can take off, but this would also be the case if the treadmill was off and the plane was just sitting there.

Ultimately, if the plane is not moving sufficiently fast relative to the ground/air, then it cannot take off.


[Edited on January 29, 2008 at 3:34 PM. Reason : adsf]

1/29/2008 3:33:10 PM

^ You're joking, right? I thought you were smarter than this.

1/29/2008 3:34:38 PM

Unfortunately, while your explanation of a plane needing air speed to fly is correct, you are incorrect in your understanding of the physics of the myth.

The plane will move forward relative to the earth, because the treadmill has no way to exert force on the plane to stop it from such movement.

1/29/2008 3:34:48 PM

wow bobby, i thought you were brighter than this...

the plane is connected to the treadmill via a frictionless surface

^ hehehehehehe that made me chuckle, "OH NOES I CAN'T DRIVE HOME THE EARTHS SPINNINGS IN THE WRONG WAYS!!!!"

[Edited on January 29, 2008 at 3:36 PM. Reason : s]

1/29/2008 3:35:04 PM

OH, THAT SHIT'S TAKING OFF BUDDY. AND WHEN IT DOES, I'MA GONNA BE ON IT.

1/29/2008 3:35:25 PM

Quote :

"the plane is connected to the treadmill via a frictionless surface"

If the surface was frictionless, then the wheels would not roll, they would slide.

1/29/2008 3:36:31 PM