Final answer to the airplane on a long treadmill problem ...

[Ruiner]

The plane will fly and here is why...

Original problem:
There is treadmill and it is as long as a runway. The plane is sitting on the treadmill. The wheels on the plane are free-rolling. The treadmill will roll, in reverse, to match the exact speed of the plane. For example, if the plane is doing 100knots, then the treadmill will sping at 100knots in reverse. Will the plane take off?

Here is a simple experiment that I just thought up to try at home for those few left that do not believe...

Do this:

Take a matchbox car and put it on a piece of paper. Now, yank the piece of paper from under the car. Does the car move backwards? Not really if at all. What little bit is attributed to the friction in the wheel bearings.Now, imagine that the car had jet engines/packs on it and it was being pushed forward already via those engines. The paper still wouldn't do shit to stop the forward motion as the wheels roll freely.

Better yet, do this:

ROLL a matchbox car along the ground/table and when it gets over the paper (while it is still moving forward), yank the paper. Does it stop the car from going forward? I mean, you will yank the paper at a MUCH faster speed than the car is moving forward. Perhaps 10 to 20x faster. The car will STILL continue to move forward even though you yanked the paper (like a treadmill would do).

That is a real world example of why the plane would take off given a treadmill that was a long as a typical runway. [/discussion about this]

[Julio]

lol.. good stuff.. that was a good thread..

[5thgcelica]

sounds like i need to find that thread and do some laughing...haha.

[Bishop]

damn, guess i missed the thread?

[Ruiner]

There, I added in the original question/problem in italics.

[5thgcelica]

damn, guess i missed the thread?


dude. we miss everything now that we live at LTC lol.

[Brady]

way to bring the OT to the whore's lounge...btw i have you a new list the pathfinders.

[5thgcelica]

There, I added in the original question/problem in italics.


thanks ruiner

[Bishop]

dude. we miss everything now that we live at LTC lol.
lol werd

[Ruiner]

way to bring the OT to the whore's lounge...btw i have you a new list the pathfinders.

Cool. Now I just need to sell the Porsche...

[gijoe0720]

And what made you just all of a sudden think of this? That thread was posted a long time ago

[Ruiner]

And what made you just all of a sudden think of this? That thread was posted a long time ago

Same thread on another board... I got tired of explaining it to the people who cannot understand.

[5thgcelica]

Cool. Now I just need to sell the Porsche...


what? you're joking right?

[Ruiner]

what? you're joking right?

No, not at all...

[5thgcelica]

No, not at all...


but why, its so gorgeous

[Ruiner]

but why, its so gorgeous

Cars come and go... I'll get another one, no worries.

[HyPer50]

The things rich people do in all there free time.....

[Big Baller]

Just like I said in the first thread, the wheel speed has absolutely no relevance at all.

[Hektik]

I dont beleive the plane will fly. Because an aircraft needs a certain amount of wind underneath its wings to help push up on it. The jets or propellers alone will not be able to lift unless there is some sort of up ward force. This is the same reason why aircraft carriers have to reach a certain speed in knots in the ocean to create enough wind at the bow of the ship to force the jets up. So if an aircraft is on a treadmill it is really not moving forward anymore than the treadmill is moving in reverse in wich case would not create the sufficient amount of force to lift the aircraft. The wheels will be spinning but the aircraft is in all reality sitting in one position.
Just my opinion.

[Ruiner]

I dont beleive the plane will fly. Because an aircraft needs a certain amount of wind underneath its wings to help push up on it. The jets or propellers alone will not be able to lift unless there is some sort of up ward force. This is the same reason why aircraft carriers have to reach a certain speed in knots in the ocean to create enough wind at the bow of the ship to force the jets up. So if an aircraft is on a treadmill it is really not moving forward anymore than the treadmill is moving in reverse in wich case would not create the sufficient amount of force to lift the aircraft. The wheels will be spinning but the aircraft is in all reality sitting in one position.
Just my opinion.

Huh? Imagine that the treadmill is as long as a normal runway. :) It will travel down the treadmill while picking up speed.

[Hektik]

Huh? Imagine that the treadmill is as long as a normal runway. :) It will travel down the treadmill while picking up speed.
If the treadmill is moving in reverse at the same speed as the wheels of the plane are moving forward the aircraft will not move forward.. If a person jumps on a treadmill and runs at 15 miles an hour and the treadmill is moving in reverse at 15 miles an hour and there is another person running at 15 miles an hour on solid ground will the person on the treadmill keep up with the person on solid ground?

[5thgcelica]

its not the wheels that propel the plane... the jet engines do. they push air. the wheels are tehre just to make it not have friction on the ground.

[Hektik]

its not the wheels that propel the plane... the jet engines do. they push air. the wheels are tehre just to make it not have friction on the ground.

correct but the engines only propelle the jet forward creating an upforce on the wings wich are what lifts the jet. just like when u drive in the car and hold ur hand out of the window the higher the speed the harder it is to lower ur hand becasue the forward thrust is what is causing ur hand to lift same thing with a jet the engines push forwrd and the wings lift.

[Ruiner]

correct but the engines only propelle the jet forward creating an upforce on the wings wich are what lifts the jet. just like when u drive in the car and hold ur hand out of the window the higher the speed the harder it is to lower ur hand becasue the forward thrust is what is causing ur hand to lift same thing with a jet the engines push forwrd and the wings lift.

Yes, we all know what causes lift. What I am showing IA.com is that the treadmill moving backwards WILL NOT affect the forward movement of the plane.

[fight club]

correct but the engines only propelle the jet forward creating an upforce on the wings wich are what lifts the jet. just like when u drive in the car and hold ur hand out of the window the higher the speed the harder it is to lower ur hand becasue the forward thrust is what is causing ur hand to lift same thing with a jet the engines push forwrd and the wings lift.


heres you a good visual. the automatic walkways at the airport. we stand next to each other and one is lined to run on the sidewalk and im running next to it. the speed you are moving is the speed of the sidewalk, but you're running in the wrong direction. you are saying that while i would reach the end, you would not move.

[Flip]

Well stated :)

[Hektik]

Yes, we all know what causes lift. What I am showing IA.com is that the treadmill moving backwards WILL NOT affect the forward movement of the plane.
If the treadmill is moving backwards at the same speed as the plane is moving forward how will the plane actually move forward. when u run on a treadmill no matter how fast u are running as long as u are running at the same speed as the treadmill u stand in one place right.

[Hektik]

heres you a good visual. the automatic walkways at the airport. we stand next to each other and one is lined to run on the sidewalk and im running next to it. the speed you are moving is the speed of the sidewalk, but you're running in the wrong direction. you are saying that while i would reach the end, you would not move.

Ok so what were saying is that the treadmill is going FORWARD and Im going FORWARD both of us at the same speed yes this will double my speed. but if im going------> that way and the treadmill is going <------ that way the 2 speeds will cancel each other out . now if what ruiner is talking about the treadmill and the plane both going the same way then yes I can understand the plane taking of but if they are going in different directions the no the plane will not fly.:goodjob:

[Ruiner]

If the treadmill is moving backwards at the same speed as the plane is moving forward how will the plane actually move forward. when u run on a treadmill no matter how fast u are running as long as u are running at the same speed as the treadmill u stand in one place right.

Umm, the engines will push it forward. The engines act on the air, not the ground. The wheels spin freely and have NO power to them. You understand this, correct? It's the same as if you are on a treadmill with roller skates and you strap on a jetpack to push you forward.

Better yet, stand on a treadmill and have a friend pull you with a rope. That rope = jet engines

[Ruiner]

Ok so what were saying is that the treadmill is going FORWARD and Im going FORWARD both of us at the same speed yes this will double my speed. but if im going------> that way and the treadmill is going <------ that way the 2 speeds will cancel each other out . now if what ruiner is talking about the treadmill and the plane both going the same way then yes I can understand the plane taking of but if they are going in different directions the no the plane will not fly.:goodjob:

Care to make a wager on this? I am confident in my stance. How confident are you in yours? Put your money where your mouth is.

I'll let you read it one more time:

Original problem:
There is treadmill and it is as long as a runway. The plane is sitting on the treadmill. The wheels on the plane are free-rolling. The treadmill will roll, in reverse, to match the exact speed of the plane. For example, if the plane is doing 100knots, then the treadmill will spin at 100knots in reverse. As the plane increases speed, so will the treadmill. Will the plane take off

[Big Baller]

Fucking damn it people, the wheel speed has absolutely no relevance at all.

[HyPer50]

Grab some of your rich friends Ruiner and lets make this happen... IA Mythbusters to the rescue.

[Hektik]

Theres no reason for me to make a wager Im completely confident on my stance but at the same time I see no reason to make this a bet plus im not a gambling man naver have been never will be. only reason im making this argument is because u asked for a discussion. and that is all it is. all im saying wether u accept it or not is that there needs to be lift u already stated that u aswell as all of IA.com know what lift is well how will there be lift if there is no actuall forward movement. please explain to make as to how there is a forward movement on a treadmill. when the treadmill is moving at 100knots to match the speed of the aircraft at 100 knots. Is the plane actually moving forward no. ok lets put it this way lets reuse the previous example ur at the airport on oje of those long escalator belts that are flat ok and u are walking in the opposite direction that the belt is moving but at the same speed you WILL stand in one single location now if u were to pick up speed and the belt stayed at the same speed then u would move but as long as u and the belt are at the same speed u will stay put.

[Hektik]

Fucking damn it people, the wheel speed has absolutely no relevance at all.
thats excatly what im saying the wyheels can spin at 100knots all day but that will not lift the jet.:goodjob: :goodjob:

[Ruiner]

Theres no reason for me to make a wager Im completely confident on my stance but at the same time I see no reason to make this a bet plus im not a gambling man naver have been never will be. only reason im making this argument is because u asked for a discussion. and that is all it is. all im saying wether u accept it or not is that there needs to be lift u already stated that u aswell as all of IA.com know what lift is well how will there be lift if there is no actuall forward movement. please explain to make as to how there is a forward movement on a treadmill. when the treadmill is moving at 100knots to match the speed of the aircraft at 100 knots. Is the plane actually moving forward no. ok lets put it this way lets reuse the previous example ur at the airport on oje of those long escalator belts that are flat ok and u are walking in the opposite direction that the belt is moving but at the same speed you WILL stand in one single location now if u were to pick up speed and the belt stayed at the same speed then u would move but as long as u and the belt are at the same speed u will stay put.

Shit, man, you are dense. Do you understand that there is NO power going to the wheels of a plane. NONE. The wheels DO NOT push the plane forward. The wheels spin freely. Knowing that, what is to stop the plane from moving forward? Remember, the wheels spin freely.

As for not betting, why not? It isn't gambling if you are 100% confident in your answer now is it? Nope. Bet me. Be a man and put your money where your mouth is...

[Hektik]

Shit, man, you are dense. Do you understand that there is NO power going to the wheels of a plane. NONE. The wheels DO NOT push the plane forward. The wheels spin freely. Knowing that, what is to stop the plane from moving forward? Remember, the wheels spin freely.

As for not betting, why not? It isn't gambling if you are 100% confident in your answer now is it? Nope. Bet me. Be a man and put your money where your mouth is...

Listen I spent the last four years of my life around jets I am 100% sure that the jet , aircraft or plane will not fly. You are correct in saying that there is NO power going to the wheels of a jet. But if the the AC is on a treadmill it will not take of because it will not move forward fast enough, IF at all, to create lift. Also I dont need to make a bet to prove Im a man Im sorry you feel that you have to. Im not trying to make this more than it is only stating what I know and what I have seen. An F/A18 fighter hornet can be propelled of an ircraft carrier on a catapult from 0-200 mph in under 3 seconds BUT unless the carrier is moving forward fast enough to create the upward wind wich will in turn create LIFT under the jets wings the jet will fall in the ocean. there for u can run a plane on a treadmill all day at 100 knots it will not fly becasue there is NO wind under its wings.......:goodjob:

[Ruiner]

Listen I spent the last four years of my life around jets I am 100% sure that the jet , aircraft or plane will not fly. You are correct in saying that there is NO power going to the wheels of a jet. But if the the AC is on a treadmill it will not take of because it will not move forward fast enough, IF at all, to create lift. Also I dont need to make a bet to prove Im a man Im sorry you feel that you have to. Im not trying to make this more than it is only stating what I know and what I have seen. An F/A18 fighter hornet can be propelled of an ircraft carrier on a catapult from 0-200 mph in under 3 seconds BUT unless the carrier is moving forward fast enough to create the upward wind wich will in turn create LIFT under the jets wings the jet will fall in the ocean. there for u can run a plane on a treadmill all day at 100 knots it will not fly becasue there is NO wind under its wings.......:goodjob:

The treadmill is as long as a runway!

Bet me! Please, please bet me!

[Hektik]

what does the length of the treadmill have to do with anything if it is going to stay in one spot?

[Hektik]

Bet me! Please, please bet me!
o and no:taun:

[fight club]

so according to your logic, if i try to run the opposite way on the moving sidewalk at an airport and im running at the same speed its rotating, i wont move?

[Ruiner]

what does the length of the treadmill have to do with anything if it is going to stay in one spot?

Because it won't stay in one spot...?

[Ruiner]

so according to your logic, if i try to run the opposite way on the moving sidewalk at an airport and im running at the same speed its rotating, i wont move?

Different logic. Your legs power you and are directly connected to the moving sidewalk. The wheels on an airplane have NO power and roll freely. The engines that "pull/push" through the air provide the power on the plane.

[Ruiner]

o and no:taun:

$10? Don't be a pussy...stick by your guns. It's easy money for you if you know 100% for sure...

[fight club]

ok so occording to his logic, if i was on roller blades and being pulled by a rope attached to a deisel truck, and tried to go the other way i wouldnt move.

[HyPer50]

Ughhh... this is a confusing ass thing... I think that if it was like a jet plane, ya it would be able to take off... it'd be the equilvenent of a RPG... all they have is thrust, no lift or movement to get them started up in the air. But then I sit here and try and imagine an old prop plane taking off without REALLY moving anywhere.... and I just can't picture it.. I mean ya, they engine would be up to speed but I dont see how it would be able to get down the runway with a treadmill moving the opposite direction... I mean, free spinning wheels would be basically the equivelent of just holding the plane in place wouldn't it? eh... fuck it, I dont understand this stuff... i'll leave it to the big boys before my head explodes...

[Ruiner]

Ughhh... this is a confusing ass thing... I think that if it was like a jet plane, ya it would be able to take off... it'd be the equilvenent of a RPG... all they have is thrust, no lift or movement to get them started up in the air. But then I sit here and try and imagine an old prop plane taking off without REALLY moving anywhere.... and I just can't picture it.. I mean ya, they engine would be up to speed but I dont see how it would be able to get down the runway with a treadmill moving the opposite direction... I mean, free spinning wheels would be basically the equivelent of just holding the plane in place wouldn't it? eh... fuck it, I dont understand this stuff... i'll leave it to the big boys before my head explodes...

No, the wheels are free-spinning. What FORCE could they really apply backwards?

[Hektik]

Different logic. Your legs power you and are directly connected to the moving sidewalk. The wheels on an airplane have NO power and roll freely. The engines that "pull/push" through the air provide the power on the plane.

you know what I will go ahead and admit defeat. you wanted a discussion and you got one. but now I see what you mean.

[Ruiner]

you know what I will go ahead and admit defeat. you wanted a discussion and you got one. but now I see what you mean.

Look at it this way:

If you have a plane on a frozen sheet of slippery ice...and the plane's wheels are locked (the brakes are on). Will the plane take off under throttle? :)

[Hektik]

Ughhh... this is a confusing ass thing... I think that if it was like a jet plane, ya it would be able to take off... it'd be the equilvenent of a RPG... all they have is thrust, no lift or movement to get them started up in the air. But then I sit here and try and imagine an old prop plane taking off without REALLY moving anywhere.... and I just can't picture it.. I mean ya, they engine would be up to speed but I dont see how it would be able to get down the runway with a treadmill moving the opposite direction... I mean, free spinning wheels would be basically the equivelent of just holding the plane in place wouldn't it? eh... fuck it, I dont understand this stuff... i'll leave it to the big boys before my head explodes...
no what ruiner is explaining is that the wheels will spin at 100knots and the treadmill will spin at 100knots BUT the jet will go forward and the treadmill will go backwards but since the wheels are free spinning they will spin backwards with the treadmill and the jet will still go forward so even though the wheels are spinning the jet will still move forward. the treadmill would have to be as long as a regular track just so the jet has enough distance to pick up speed but the wheels will just spin regarless:goodjob:

[Hektik]

Look at it this way:

If you have a plane on a frozen sheet of slippery ice...and the plane's wheels are locked (the brakes are on). Will the plane take off under throttle? :)

yea I get what ur saying now :goodjob: . The wheels have nothing to do with it and the treadmill does nothing as well becasue the jets are pushing forward. im still keeping my $10 though:D

[Ruiner]

no what ruiner is explaining is that the wheels will spin at 100knots and the treadmill will spin at 100knots BUT the jet will go forward and the treadmill will go backwards but since the wheels are free spinning they will spin backwards with the treadmill and the jet will still go forward so even though the wheels are spinning the jet will still move forward. the treadmill would have to be as long as a regular track just so the jet has enough distance to pick up speed but the wheels will just spin regarless:goodjob:

BINGO! Actually,the wheels would spin at 2x the rate of the forward movement...

http://i4.tinypic.com/10ngozs.jpg

[Hektik]

BINGO! Actually,the wheels would spin at 2x the rate of the forward movement...

http://i4.tinypic.com/10ngozs.jpg

got it nice diagram to

[SampaGuy]

if u hold a shopping on a cart on a treadmill, the wheels of the cart will be going say 10mph while the treadmill goes -10mph. the cart however, does not move. if u accelerate the treadmill to -20mph, the wheels of the cart will spin at 20mph but the cart will still not move. therefore it doesnt matter what speed the treadmill goes because the wheels are free spinning. so now that u have a cart not moving, but rolling along with the treadmill, put jet engines on it. will the cart move forward? get it?

[Ruiner]

yea I get what ur saying now :goodjob: . The wheels have nothing to do with it and the treadmill does nothing as well becasue the jets are pushing forward. im still keeping my $10 though:D

You made a wise choice. :goodjob:

[Hektik]

You made a wise choice. :goodjob:
I lied I gambled once in my life it was a quarter (25c) in a casino lost them will never do it again:D

[HyPer50]

No, the wheels are free-spinning. What FORCE could they really apply backwards?

I dont see them applying any force, but I just can't see them moving forward, rather just spinning in place since the plane is pulling them one direction, and the treadmill is pulling them in the opposite at the same speed. like i said, i'm just gonna leave this to you guys... never claimed i was smart when it comes to these type of things lol... i'm much more a visual/hands on person than i am able to do crap in my head lol...

[ATK_Designs]

I'm late and I like your explanation. Your Idea of freely spinning wheels is true, but remeber, there are power to the treadmill. So it's like an opposite upside down situation.

So it's like how your car is being dyno or when you do the OBDI Emission check. The Plane will be the rollers of the machine (don't know what's it called) and the Treadmill is the car itself.

However, your "real life" experience has nothing to do with the plane on the treadmill since

A. The paper doesn't work the same way as the tread mill. Treadmill puts out torque and power.
B. Plane requires horizontal air movement to lift it up.

Since:

1. PLane has +A velocity on +X Direction
2. Treadmill has -A Velocity on -X direction.

According to Physic,

If there's equal and opposite force that applied at the same time, there won't be any changes in the X direction movement.

Therefore, there won't be any -A^n velocity of the air movement.

The plane will not take off.

[ShooterMcGavin]

ok reading through this entire thing and hearing mostly ruiner and hektik debate, i'll have to say that my first instinct was to say the plane won't take off. while i understand that the wheels are free spinning, i still believe that the jet engines are what causes the wheels to spin at any speed (which is then matched by the treadmill), therefore causing the plane to stay in the same place.

however, after reading through ruiner's further explanation, i came to think that maybe he is right. yet the only way i'd agree with that is if somehow, the wheel speed does not match the treadmill speed. by that i mean the jet engines can propel it enough to where the wheels will outspin the treadmill, thereby giving it forward movement and lift and all that. but then again, this doesn't really agree with ruiner's original supposition.

after reading interlude's post just now, i'm back to thinking that this plane will not take off......either way though, thanks for making me think like this, it's been a while :D

[Ruiner]

I'm late and I like your explanation. Your Idea of freely spinning wheels is true, but remeber, there are power to the treadmill. So it's like an opposite upside down situation.

So it's like how your car is being dyno or when you do the OBDI Emission check. The Plane will be the rollers of the machine (don't know what's it called) and the Treadmill is the car itself.

However, your "real life" experience has nothing to do with the plane on the treadmill since

A. The paper doesn't work the same way as the tread mill. Treadmill puts out torque and power.
B. Plane requires horizontal air movement to lift it up.

Since:

1. PLane has +A velocity on +X Direction
2. Treadmill has -A Velocity on -X direction.

According to Physic,

If there's equal and opposite force that applied at the same time, there won't be any changes in the X direction movement.

Therefore, there won't be any -A^n velocity of the air movement.

The plane will not take off.

If you are so sure, then take a bet with me.

I will say this: you are wrong. :)

It IS NOT like your car on a dyno. In a car, the power goes to the wheels. In a plane, it "pushes" through the air via the engines. There is NO connection with the ground. BIG difference. Answer me this: how does a plane with sleds on the bottom take off in the snow? No wheels...

The plane, no matter how fast the treadmill is spinning, will push forward, THROUGH the air, and down the treadmill (that is as long as a runway). During that time, the plane will pick up speed and finally reach take off velocity.

If you don't believe me, bet me. :) It's VERY simple.

[Ruiner]

after reading interlude's post just now, i'm back to thinking that this plane will not take off......either way though, thanks for making me think like this, it's been a while :D

If you don't believe that it will take off, then bet me. Put up or shut up. :)

[Ruiner]

if u hold a shopping on a cart on a treadmill, the wheels of the cart will be going say 10mph while the treadmill goes -10mph. the cart however, does not move. if u accelerate the treadmill to -20mph, the wheels of the cart will spin at 20mph but the cart will still not move. therefore it doesnt matter what speed the treadmill goes because the wheels are free spinning. so now that u have a cart not moving, but rolling along with the treadmill, put jet engines on it. will the cart move forward? get it?

Apparently nobody else gets it, though. That worries me, honestly. It's a VERY simple concept. The treadmill is only there to cause confusion, but that's it. The plane will still take off (given a long enough treadmill).

[ShooterMcGavin]

If you are so sure, then take a bet with me.

I will say this: you are wrong. :)

It IS NOT like your car on a dyno. In a car, the power goes to the wheels. In a plane, it "pushes" through the air. BIG difference.

The plane, no matter how fast the treadmill is spinning, will push forward, THROUGH the air, and down the treadmill (that is as long as a runway). During that time, the plane will pick up speed and finally reach take off velocity.

If you don't believe me, bet me. :) It's VERY simple.

i do believe you, IF you can concur that in order for the plane to actually move forward on the treadmill and take off, it's wheels will have to spin at a faster speed than the treadmill. because although i agree there is no power going directly to the wheels (therefore making it different than a car, or a person running), the plane is still "grounded" via the wheels, and needs the wheels in order for traction and to pick up speed with.

[Ruiner]

i do believe you, IF you can concur that in order for the plane to actually move forward on the treadmill and take off, it's wheels will have to spin at a faster speed than the treadmill. because although i agree there is no power going directly to the wheels (therefore making it different than a car, or a person running), the plane is still "grounded" via the wheels, and needs the wheels in order for traction and to pick up speed with.

Traction? No

Let me ask you this:

A plane is sitting on a huge frozen lake bed. The frozen sheet is slippery. The plane locks its wheels (puts the brakes on) and then applies engine thrust. Will the plane take off?

[ShooterMcGavin]

i believe traction is present and valid considering it's on a treadmill, however, i see your point that it can be arbitrary. however, what i seem to have trouble conceiving is how the plane will actually MOVE DOWN this treadmill when the treadmill is moving against it at whatever speed the wheels are spinning :thinking: and yes, that plane on the frozen lake will take off (only if you have iceman from top gun flying it though :D )

[chrisdavis]

i do believe you, IF you can concur that in order for the plane to actually move forward on the treadmill and take off, it's wheels will have to spin at a faster speed than the treadmill. because although i agree there is no power going directly to the wheels (therefore making it different than a car, or a person running), the plane is still "grounded" via the wheels, and needs the wheels in order for traction and to pick up speed with.

Take the treadmill out of the equation. Suspend the plane from cables(plane not touching the ground) and fire up the engines. Once the plane has enough thust it will move forward. The wheels merely reduce friction between the ground. At some point the plane's engine overcomes the weight of the plane itself and moves forward.

[Ruiner]

i believe traction is present and valid considering it's on a treadmill, however, i see your point that it can be arbitrary. however, what i seem to have trouble conceiving is how the plane will actually MOVE DOWN this treadmill when the treadmill is moving against it at whatever speed the wheels are spinning :thinking: and yes, that plane on the frozen lake will take off (only if you have iceman from top gun flying it though :D )


Think about it this way:

- Stand on a treadmill with roller skates....
- Hold onto the bar and keep yourself stationary.
- At this point, your wheels and ONLY your wheels are spinning at the speed of the treadmill. You are stationary.
- Now, try to pull yourself forward. It should be VERY easy to do. Increase the treadmill speed. Still easy to pull yourself forward.
- Now, imagine that you strapped a jetpack on your back and used those engines to "push" you forward while still on the treadmill.
- The jetpack = a plane's engines

It's VERY simple... you will move forward and increase speed much like a plane will move forward, increase speed after enough distance, and finally take off.

[ShooterMcGavin]

exactly, i understand/comprehend that perfectly. i guess what i am really curious about, and something that originally put doubt into my head (as well as countless others who have thought about this), is that when the thrust from the engines starts to push the plane forward, what exactly are the wheels doing? as in, what is the speed of the wheels? (even though i realize this is arbitrary!)

[Ruiner]

exactly, i understand/comprehend that perfectly. i guess what i am really curious about, and something that originally put doubt into my head (as well as countless others who have thought about this), is that when the thrust from the engines starts to push the plane forward, what exactly are the wheels doing? as in, what is the speed of the wheels? (even though i realize this is arbitrary!)

The wheels are spinning and nothing else! That is the fun of it. The wheels ONLY spin, freely! Actually, the wheels will spin at twice the rate of forward motion of the plane as the treadmill is doing the same speed in reverse.

So, the plane is moving at 100knots forward and the treadmill is doing 100knots in reverse...the wheels are spinning (and ONLY SPINNING) at 200knots. They still have no affect on the plane's forward motion. All the treadmill does is spin the wheels.

http://i4.tinypic.com/10ngozs.jpg

[ShooterMcGavin]

The wheels are spinning and nothing else! That is the fun of it. The wheels ONLY spin, freely! Actually, the wheels will spin at twice the rate of forward motion of the plane as the treadmill is doing the same speed in reverse.

So, the plane is moving at 100knots forward and the treadmill is doing 100knots in reverse...the wheels are spinning (and ONLY SPINNING) at 200knots. They still have no affect on the plane's forward motion. All the treadmill does is spin the wheels.

http://i4.tinypic.com/10ngozs.jpg

perfect! that was my thinking originally, that in order for the plane to MOVE FORWARD, the RATE at which the wheels were spinning could not equal the rate of the treadmill moving against it (and speed of the treadmill and the wheels really have no bearing on whether or not the plane will take off). see? i'm with ya, just had to make sure i was understanding all parts of this "situation" :D :goodjob: :yay:

[Z0_o6]

hehe what happens when a wheel bearing locks up? :P I do completely understand though. as long as the jet engines are able to put force on something that isn't counteracting them, the plane will move. there is forward thrust regardless.

[Ruiner]

perfect! that was my thinking originally, that in order for the plane to MOVE FORWARD, the RATE at which the wheels were spinning could not equal the rate of the treadmill moving against it (and speed of the treadmill and the wheels really have no bearing on whether or not the plane will take off). see? i'm with ya, just had to make sure i was understanding all parts of this "situation" :D :goodjob: :yay:

Your logic is still off. It has NOTHING to do with how fast the wheels are spinning, NOTHING. As I said earlier, a plane could take off with NO wheels on the snow or no wheels in the water or locked wheels on a sheet of ice.

The plane has to overcome the friction produced by the wheels. Since the wheels are free spinning, then the only friction that they are producing comes from the bearings... that's it. Once it overcomes that little bit of friction, the plane moves forward.

[{X}Echo419]

the plane can't fly. it's been proven. since the plane is no moving there is no drag thus no lift.
hell, if it was possible the Navy would have giant floating treadmill. :2cents:

[ShooterMcGavin]

Your logic is still off. It has NOTHING to do with how fast the wheels are spinning, NOTHING. As I said earlier, a plane could take off with NO wheels on the snow or no wheels in the water or locked wheels on a sheet of ice.

The plane has to overcome the friction produced by the wheels. Since the wheels are free spinning, then the only friction that they are producing comes from the bearings... that's it. Once it overcomes that little bit of friction, the plane moves forward.

i think maybe you're misunderstanding me or i didn't explain myself well enough? i understand the speed of the wheels have nothing to do with this equation, it's all about the force that's being applied by the engines. however, and please tell me if this is where i'm wrong, i believe the wheels must spin at a higher rate than the treadmill moving against it AS A BYPRODUCT of the force being applied to move the plane forward. because if this is not the case, then why is it that the wheels would freely spin at twice the rate of the treadmill? hope this clears it up for good :tongue:

[Ruiner]

the plane can't fly. it's been proven. since the plane is no moving there is no drag thus no lift.
hell, if it was possible the Navy would have giant floating treadmill. :2cents:

What would stop the plane from moving if it applied thrust from its engines?

[Ruiner]

i think maybe you're misunderstanding me or i didn't explain myself well enough? i understand the speed of the wheels have nothing to do with this equation, it's all about the force that's being applied by the engines. however, and please tell me if this is where i'm wrong, i believe the wheels must spin at a higher rate than the treadmill moving against it AS A BYPRODUCT of the force being applied to move the plane forward. because if this is not the case, then why is it that the wheels would freely spin at twice the rate of the treadmill? hope this clears it up for good :tongue:

Look at it this way: if the plane was in the air and YOU were making the wheels on the plane spin, would the plane fall out of the air? That's all that the treadmill is doing...spinning the wheels. NOTHING MORE.

Look at the diagram again and you will understand why the wheels spin at the plane's forward speed + the treadmill's speed:

http://i4.tinypic.com/10ngozs.jpg

[Ruiner]

the plane can't fly. it's been proven. since the plane is no moving there is no drag thus no lift.
hell, if it was possible the Navy would have giant floating treadmill. :2cents:

BET ME! Please, be a man and bet me if it is such a sure thing.

[ShooterMcGavin]

Look at it this way: if the plane was in the air and YOU were making the wheels on the plane spin, would the plane fall out of the air? That's all that the treadmill is doing...spinning the wheels. NOTHING MORE.

Look at the diagram again and you will understand why the wheels spin at the plane's forward speed + the treadmill's speed:

http://i4.tinypic.com/10ngozs.jpg

can't see the pic cuz it's being blocked by websense :doh: but i understand what you're saying and even though i don't think i'm expressing it correctly, what i'm saying is what you're saying :D

and to hopefully prove that i do fully comprehend, here's a simple followup question that you can easily answer: would it be possible to have/build a treadmill that will move/accelerate in a manner in which it will actually keep the plane in the same spot and grounded?

[ShooterMcGavin]

BET ME! Please, be a man and bet me if it is such a sure thing.
lirl, all about betting today huh? i understand though with that new place you're getting, mortgages are a bitch :D

[ATK_Designs]

If you are so sure, then take a bet with me.

I will say this: you are wrong. :)

It IS NOT like your car on a dyno. In a car, the power goes to the wheels. In a plane, it "pushes" through the air via the engines. There is NO connection with the ground. BIG difference. Answer me this: how does a plane with sleds on the bottom take off in the snow? No wheels...

The plane, no matter how fast the treadmill is spinning, will push forward, THROUGH the air, and down the treadmill (that is as long as a runway). During that time, the plane will pick up speed and finally reach take off velocity.

If you don't believe me, bet me. :) It's VERY simple.

1. I said that plane = dyno roller, treadmill = car. Please reread what i said.

2. Plane will take off on snow since there AREN'T any -A Velocity on X axis with -hp & -tq. Also, the snow surface is STATIONARY has enough friction for the plane to grip on. Treadmill has -A Velocity on X axis with -hp & -tq. It counters every +A velocity in the +X direction.

3. Plane doesn't require right velocity/speed to lift off, it requires enough lift force of the air movement. It relies on its speed to help it move ALONG the density of the air to cause enough lift. If the plan is to run on the space runway where there aren't any air, it will not have any vertical movement. It will move VERY fast on the outerspace runway, but not UP unless it has a thrust engine to push it up and changes its Y directional velocity. The plane can run at 500mph on the runway while the air is moving at the SAME velocity and SAME force and SAME direction as the plane, it still WILL NOT take off.

I don't believe it bet. :o But I understand your concept very well.

It's time for the Mythbuster to prove this. :doh:

Also, the PLANE WILL TAKE OFF on the treadmill if it has this condition:

A thrust engine that creates +B velocity in +Y direction.

If its thrust engine only has purely +A Velocity in +X Direction, it WILL NOT take off.

[Ruiner]

can't see the pic cuz it's being blocked by websense :doh: but i understand what you're saying and even though i don't think i'm expressing it correctly, what i'm saying is what you're saying :D

and to hopefully prove that i do fully comprehend, here's a simple followup question that you can easily answer: would it be possible to have/build a treadmill that will move/accelerate in a manner in which it will actually keep the plane in the same spot and grounded?

As long as the wheels are free rolling (neutral), no, not really. There is a small amount of friction in the wheel bearings. If the plane's thrust matches that friction, exactly, then the plane will stay stationary. Once the plane's thrust passes that friction amount, the plane will move forward.

[Ruiner]

1. I said that plane = dyno roller, treadmill = car. Please reread what i said.

2. Plane will take off on snow since there AREN'T any -A Velocity on X axis with -hp & -tq. Also, the snow will have enough friction for the plan to grip on. Treadmill has -A Velocity on X axis with -hp & -tq. It counters every +A velocity in the +X direction.

3. Plane doesn't require right velocity/speed to lift off, it requires enough lift force of the air movement. It relies on its speed to help it move ALONG the density of the air to cause enough lift. If the plan is to run on the space runway where there aren't any air, it will not have any vertical movement. It will move VERY fast on the outerspace runway, but not UP unless it has a thrust engine to push it up and changes its Y directional velocity. The plane can run at 500mph on the runway while the air is moving at the SAME velocity and SAME force and SAME direction as the plane, it still WILL NOT take off.

I don't believe it bet. :o But I understand your concept very well.

It's time for the Mythbuster to prove this. :doh:

A plane DOES require velocity/speed to lift. The speed of the air over the top of the wing vs over the bottom of the wing creates a pressure difference and that is what gives you lift.

Wrong on the bolded part. How can a treadmill counteract the FORWARD push of the engines by spinning the wheels of a plane? All it does is spin the wheels. Answer me that. I just busted your theory, btw...

[ShooterMcGavin]

As long as the wheels are free rolling (neutral), no, not really. There is a small amount of friction in the wheel bearings. If the plane's thrust matches that friction, exactly, then the plane will stay stationary. Once the plane's thrust passes that friction amount, the plane will move forward.

but the key is, what if said treadmill can accelerate constantly? F=ma, so whatever force is provided by engines, it can be equally matched and exceeded by the treadmill if it has enough acceleration, no?

[ATK_Designs]

A plane DOES require velocity/speed to lift. The speed of the air over the top of the wing vs over the bottom of the wing creates a pressure difference and that is what gives you lift.

Wrong on the bolded part. How can a treadmill counteract the FORWARD push of the engines by spinning the wheels of a plane? All it does is spin the wheels. Answer me that. I just busted your theory, btw...

Again, for the 3rd time.

The plane's wheels are the same thing as the dyno's roller. It outputs no pwr or tq. ;)

The treadmill does output HP and TQ, in negative direction. ;)


So imagine it this way, instead of having your porsche sexing up on top of the dyno, this time, the dyno is doing a reverse cowboy (on top) on your porsche :idb:

Also: I said that the plan doesn't require the RIGHT velocity, not that it doesn't require ANY velocity at all. I was, however, wrong in the mean that it does require the velocity. What I meant was that it Does not require the exact same *book* velocity to lift off. Each plane is different and also in each situation (atmosphere density)

[Ruiner]

Again, for the 3rd time.

The plane's wheels are the same thing as the dyno's roller. It outputs no pwr or tq. ;)

The treadmill does output HP and TQ, in negative direction. ;)


So imagine it this way, instead of having your porsche sexing up on top of the dyno, this time, the dyno is doing a reverse cowboy (on top) on your porsche :idb:

No, it is not the same:

The wheels on my car are powered by my engine... what are the wheels powered by on a plane?

Another example: Let's say that my car is on a dyno in neutral...and I have a jet engine attached to it. I crank up the engine, what happens to my car on the dyno?

[Ruiner]

Interlude, you do realize that the statement "The treadmill does output HP and TQ, in negative direction" is true, but that it is ONLY doing this on free-spinning wheels, right?

[ATK_Designs]

No, it is not the same:

The wheels on my car are powered by my engine... what are the wheels powered by on a plane?

Another example: Let's say that my car is on a dyno in neutral...and I have a jet engine attached to it. I crank up the engine, what happens to my car on the dyno?

Dude, the wheels of the plane are freespining. I was sampled backward. If you must match the plane/treadmill (motorized) example, you must attach the jet engine TO the dyno.

In that case you'll move the whole Dyno station backward. But in this subject, the car (treadmill) must have matching negative speed as the dyno wheels are putting. ;)


Interlude, you do realize that the statement "The treadmill does output HP and TQ, in negative direction" is true, but that it is ONLY doing this on free-spinning wheels, right?

I was talking about the motorized treadmill.

So in this subject, the treadmill is free spinning and NOT motorized??:confused:

If so, you're 100% correct. It's the same as those air plane on the water. It WILL LIFT OFF.

[Ruiner]

I was talking about the motorized treadmill.

So in this subject, the treadmill is free spinning and NOT motorized??:confused:

If so, you're 100% correct. It's the same as those air plane on the water. It WILL LIFT OFF.

No, the treadmill is motorized, but the wheels of the plane are free spinning. The treadmill has torque, but it ONLY applies it to wheels that are free spinning.

Your dyno question was wrong in a sense. The wheels on the car would need to be free spinning (in neutral) as well. Will the dyno work and apply torque to the car if the car is in neutral? Nope. Just like the treadmill will not apply torque to the plane if the wheels are free spinning.

[ATK_Designs]

No, the treadmill is motorized, but the wheels of the plane are free spinning. The treadmill has torque, but it ONLY applies it to wheels that are free spinning.

Your dyno question was wrong in a sense. The wheels on the car would need to be free spinning (in neutral) as well. Will the dyno work and apply torque to the car if the car is in neutral? Nope. Just like the treadmill will not apply torque to the plane if the wheels are free spinning.

Oh okay,

but I was NOT talking in the sense that your car is in neutral + jet engine, no, not that.

I was talking about the plane's wheels = the same as the dyno's rollers.
And the treadmill = the car itself.

Lift up or not is based on air pressure. if there aren't any, plane will not lift off. Also, the treadmill will adjusting its negative velocity accordingly to the plane's.

Using the car vs dyno was a bad example. It was only to show you that the treadmill does output torque and HP in negative X direction to cancel out the free rolling velocity in positive X direction.

[Ruiner]

Oh okay,

but I was NOT talking in the sense that your car is in neutral + jet engine, no, not that.

I was talking about the plane's wheels = the same as the dyno's rollers.
And the treadmill = the car itself.

Lift up or not is based on air pressure. if there aren't any, plane will not lift off. Also, the treadmill will adjusting its negative velocity accordingly to the plane's.

Using the car vs dyno was a bad example. It was only to show you that the treadmill does output torque and HP in negative X direction to cancel out the free rolling velocity in positive X direction.

HOW is it cancelling the forward velocity, though?

Answer these questions for me:
- The treadmill is only spinning the wheels of the plane, yes?
- The wheels of the plane are free rolling, yes?
- Can spinning free rolling wheels cancel out the forward velocity of the plane?

I want you to think about that last question really hard... It actually makes the wheels spin faster. Look below:

http://i4.tinypic.com/10ngozs.jpg

[3kgtdrvr]

wow, that was a lot to read and really confusing to lol i didnt even get halfway before i gave up but i think as long as the plane it moving foward it should take off. if the treadmill can move and not pull the plane with it = 0 resisance or friction between the wheels and the treadmill and inside the wheels or wheel bearing so the treadmill can spin and the plane stay still so that 100% of the force of the engines goes towards pushing the plane then it should take off without any problem. damn good question though! really got me thinking :goodjob:

[Ruiner]

wow, that was a lot to read and really confusing to lol i didnt even get halfway before i gave up but i think as long as the plane it moving foward it should take off. if the treadmill can move and not pull the plane with it = 0 resisance or friction between the wheels and the treadmill and inside the wheels or wheel bearing so the treadmill can spin and the plane stay still so that 100% of the force of the engines goes towards pushing the plane then it should take off without any problem. damn good question though! really got me thinking :goodjob:

Even with friction in the wheel bearings, the plane's thrust will easily overcome that...

[Xan]

The propellers provide the thrust. Tricky question first time you hear it.

[ShooterMcGavin]

but the key is, what if said treadmill can accelerate constantly? F=ma, so whatever force is provided by engines, it can be equally matched and exceeded by the treadmill if it has enough acceleration, no?

ruiner? anything?

[Ruiner]

ruiner? anything?

The treadmill matches the SPEED of the plane, not the thrust. The tread mill can be moving at 100,000knots while the plane is going at 100knots. It WOULD NOT matter. It would ONLY make the wheels spin at 100,100knots. NOTHING MORE. Guys, the wheels would spin faster, but that would not change the thrust up the engines.

The treadmill in NO way can counteract the THRUST of the engines.

[JennB]

You are correct.

It's much simpler than it sounds. So many people think in terms of cars when there really isn't a relation. Cars are moved by their wheels, planes are not. The wheels on the plane might as well not even be there, they have no effect at all on the movement of the plane. The engines move it through the air and will do that it the wheels are spinning or if the plane is on water even.



(I'm sure something like that has been said at one point, but damn this thread is long)

[Ruiner]

You are correct.

It's much simpler than it sounds. So many people think in terms of cars when there really isn't a relation. Cars are moved by their wheels, planes are not. The wheels on the plane might as well not even be there, they have no effect at all on the movement of the plane. The engines move it through the air and will do that it the wheels are spinning or if the plane is on water even.



(I'm sure something like that has been said at one point, but damn this thread is long)

How come their minds cannot grasp this concept? I see that you are about my age...perhaps it comes with age and schooling? I dunno...

[speedminded]

The treadmill matches the SPEED of the plane, not the thrust. The tread mill can be moving at 100,000knots while the plane is going at 100knots. It WOULD NOT matter. It would ONLY make the wheels spin at 100,100knots. NOTHING MORE. Guys, the wheels would spin faster, but that would not change the thrust up the engines.

The treadmill in NO way can counteract the THRUST of the engines.lemme help you out with the porsche on the dyno analogy....imagine a vehicle on the dyno in neutral...the wheels are free spinning just as a planes wheels are. Now imagine if that car was not strapped down on the dyno, it should remain free wheeling on top of the rollers even if power were applied to the dyno (like a treadmill) in turn causing the wheels to spin. Ok so now you would have a car sitting there with wheels spinning but not going anywhere (ever seen anyone spin 2 basketballs on top of each other or a man running on a floating barrel or log in the water?) Same idea, one causes the other to spin but since the bottom one is stationary neither go anywhere.

Anyways, back to the car on the dyno...it's not strapped down and no power is being supplied to the wheels. Now imagine if you had 4 people or even just one person run and push the back of the vehicle...is the car still going to go forward? yes. Now if you turn on the engines of the plane is it going to go anywhere? yes.

[JennB]

How come their minds cannot grasp this concept? I see that you are about my age...perhaps it comes with age and schooling? I dunno...


It's just hard to make the separation of concepts.

We're probably both very logical people so it's easier for us to understand.



Now emotions, I don't understand. Math and science, I'm on it.

[ATK_Designs]

all of this, with pictures and all; yet, you forgot the weight & Gravity.

I'm not going to try and argue any further. It's infact very simple. All engineers that I know also say that the plan will not take up.

remember,

1. Air plane thrust engine give it +X Velocity
2. Plane's weight give it -Y Velocity
3. Gravity weight adds to that -Y velocity
4. Treadmill gives enqual -X Velocity.

So, I will not trying to be precise, but instead be very simple about it, you have

X - 2Y = Plane's velocity
-X = Treadmill Velocity

Put them on the equation, you still end up with -2Y. You need Possitive Y to give it lifts. That above is not entirely correct equation since you'd have to factor in a lot more, however, it'll just yield extra -Y velocity, of which would further strengthen the concept.

X & Y are X-Y Axis of directionals

Anyone know physics can always tell this. I'm not saying I'm right since I'm also an engineer, but if a bunch of others senior engineers who said the same thing as I am, there must be a common.

I don't want to argue anymore if you don't understand. Have a good day. :)

[Vteckidd]

ill bet $1000 that the plane WOULD fly. Ruiner find the video that the kids made with the skateboard. that is all the proof you need.

the wheels arent driving the plane forward. The ENGINES in the rear are. an the plane will achieve thrust an lift off

[Vteckidd]

Anyways, back to the car on the dyno...it's not strapped down and no power is being supplied to the wheels. Now imagine if you had 4 people or even just one person run and push the back of the vehicle...is the car still going to go forward? yes. Now if you turn on the engines of the plane is it going to go anywhere? yes.
EGGSFUCKINGZACTLY

[speedminded]

all of this, with pictures and all; yet, you forgot the weight & Gravity.

I'm not going to try and argue any further. It's infact very simple. All engineers that I know also say that the plan will not take up.

remember,

1. Air plane thrust engine give it +X Velocity
2. Plane's weight give it -Y Velocity
3. Gravity weight adds to that -Y velocity
4. Treadmill gives enqual -X Velocity.

So, I will not trying to be precise, but instead be very simple about it, you have

X - 2Y = Plane's velocity
-X = Treadmill Velocity

Put them on the equation, you still end up with -2Y. You need Possitive Y to give it lifts. That above is not entirely correct equation since you'd have to factor in a lot more, however, it'll just yield extra -Y velocity, of which would further strengthen the concept.

X & Y are X-Y Axis of directionals

Anyone know physics can always tell this. I'm not saying I'm right since I'm also an engineer, but if a bunch of others senior engineers who said the same thing as I am, there must be a common.

I don't want to argue anymore if you don't understand. Have a good day. :)Let's make it simple, the treadmill in no way what so ever will ever prevent the plane from moving forward...no matter what. Therefore gravity, lift, thrust, etc. everything is EXACTLY the same as if it were on a tarmac. Period.

Ask those same engineers if it's possible to drive into the back of a moving truck, just as KITT did in Knight Rider or the SSR does on it's commercial where it does a 180° onto the trailer...

[fight club]

Let's make it simple, the treadmill in no way what so ever will ever prevent the plane from moving forward...no matter what. Therefore gravity, lift, thrust, etc. everything is EXACTLY the same as if it were on a tarmac. Period.

Ask those same engineers if it's possible to drive into the back of a moving truck, just as KITT did in Knight Rider or the SSR does on it's commercial where it does a 180° onto the trailer...
its very possible. ive done it loads of times... in spyhunter. :D

[ATK_Designs]

Let's make it simple, the treadmill in no way what so ever will ever prevent the plane from moving forward...no matter what. Therefore gravity, lift, thrust, etc. everything is EXACTLY the same as if it were on a tarmac. Period.

Ask those same engineers if it's possible to drive into the back of a moving truck, just as KITT did in Knight Rider or the SSR does on it's commercial where it does a 180° onto the trailer...


:o They can just stop working since they're earning well over 6-figure incomes.

About the car on the dyno, please read what I said TONS of time before, it's the UPSIDE DOWN Example.

Treadmill = car = output tq & hp
Plane = Dyno = no tq/hp - free wheelies.

YOU CANNOT STRAP A THRUST ENGINE ONTO THE CAR AND COMPARE IT, since it'd be the same as strapping the engine onto the treadmill.

I said that using it was a bad example since I don't know how dyno works (whether it actually can spin its roller or not).

[speedminded]

:o They can just stop working since they're earning well over 6-figure incomes.I sure hope it's not in aeronautical engineering!

[speedminded]

:o They can just stop working since they're earning well over 6-figure incomes.

About the car on the dyno, please read what I said TONS of time before, it's the UPSIDE DOWN Example.

Treadmill = car = output tq & hp
Plane = Dyno = no tq/hp - free wheelies.

YOU CANNOT STRAP A THRUST ENGINE ONTO THE CAR AND COMPARE IT, since it'd be the same as strapping the engine onto the treadmill.

I said that using it was a bad example since I don't know how dyno works (whether it actually can spin its roller or not).See my dyno example, it explains it perfectly.

[ATK_Designs]

I sure hope it's not in aeronautical engineering!

They're mixed, some of them are Telcom, hardware, and some work for Lockheed Martin. When I asked them this question, they laughed and said that this been discussed a longggggg time ago, even before I was born. It was one of the trick to stir up the discussions.

[{X}Echo419]

What would stop the plane from moving if it applied thrust from its engines?

because the Plance is not going anywhere.

it's the wind passing over the wings(called drag) and making the plane fly.

ya know what you can do(maybe) but a remote controled air plane on a treadmill put the threadmill on full speed then put the plane on it and try to fly it.
the plane will probally fall off or at best stay on the treadmill and not gain "any" altitude".

[fight club]

all of this, with pictures and all; yet, you forgot the weight & Gravity.

I'm not going to try and argue any further. It's infact very simple. All engineers that I know also say that the plan will not take up.

remember,

1. Air plane thrust engine give it +X Velocity
2. Plane's weight give it -Y Velocity
3. Gravity weight adds to that -Y velocity
4. Treadmill gives enqual -X Velocity.

So, I will not trying to be precise, but instead be very simple about it, you have

X - 2Y = Plane's velocity
-X = Treadmill Velocity

Put them on the equation, you still end up with -2Y. You need Possitive Y to give it lifts. That above is not entirely correct equation since you'd have to factor in a lot more, however, it'll just yield extra -Y velocity, of which would further strengthen the concept.

X & Y are X-Y Axis of directionals

Anyone know physics can always tell this. I'm not saying I'm right since I'm also an engineer, but if a bunch of others senior engineers who said the same thing as I am, there must be a common.

I don't want to argue anymore if you don't understand. Have a good day. :)


your weight on earth is the force of gravity upon any material object. you cant factor it in twice.

[ATK_Designs]

See my dyno example, it explains it perfectly.

I read that, it's different than my example.

However, you forgot the fact that you need people pushing it and perfect horizonal movement, NOT having any UP force, while the dyno rollers are motorized AND rolling in separate direction - NOT freewheeling.

That's why I said that using the car & Dyno was a bad example. Since it has different factors, for example: Dyno's rollers doesn't act the same as treadmill since it doesn't have full surface movement but rather, spot movement.

Oh well, believe what you want,

I'm tired of all this typing. :D

Edit; cherry kool aid (member.php?u=3705) you're correct, I forgot, I factored it twice. Thanks for correcting.

[speedminded]

They're mixed, some of them are Telcom, hardware, and some work for Lockheed Martin. When I asked them this question, they laughed and said that this been discussed a longggggg time ago, even before I was born. It was one of the trick to stir up the discussions.Since they are all engineers and have the money why don't they build me a small scale version of this situation: a treadmill not much more than 10-12' long should be sufficient and a radio controlled airplane capable of some sort of remote start...

[fight club]

no problem!

[JennB]

http://www.straightdope.com/columns/060203.html

[ShooterMcGavin]

read this, it's an avaitor/engineer POV on this whole thing, it's lengthy but it explains in full detail:

http://www.avweb.com/news/columns/191034-1.html

[ShooterMcGavin]

The treadmill matches the SPEED of the plane, not the thrust. The tread mill can be moving at 100,000knots while the plane is going at 100knots. It WOULD NOT matter. It would ONLY make the wheels spin at 100,100knots. NOTHING MORE. Guys, the wheels would spin faster, but that would not change the thrust up the engines.

The treadmill in NO way can counteract the THRUST of the engines.
correct, that's not what i was saying and i'm acknowledging this is a departure from the original question. the followup question involves whether or not a treadmill could be designed to match the FORCE (or acceleration) of the plane. in which case, wouldn't the answer be yes?

[swiftblaze]

In regards to Echo's post,

The remote control plane idea is flawed because it needs to travel a longer distance in order to generatete enough lift to take off. I can guarantee you that the plane will move forward. As stated earlier, stand on a treadmill with rollerskates and hold on to the front bar. Set the treadmill to a high setting and attempt to pull yourself forward. You will be able to very easily. This contradicts your previous statements stating that the "plance" will not move forward. The wheels are freely spinning and do not affect the thrust pushing the plane forward. A remote control plane will move forward on the treadmill fine, but it does not have near enough distance to take off. On the other hand, a treadmill the size of a runway will provide adequate distance for a plane to be able to take off.

I have an interesting idea. This same giant treadmill can be used in the car scene as well. If you place a car on a treadmill while in neutral and attach a jet engine in the trunk, will it move forward? Yes! The wheels are not providing any power whatsoever. The jet engine mounted in the trunk of the car will push the car foward against the treadmill since the wheels are only acting as a contact point between the car and the ground. The car can gain quite a bit of speed as well. Now, image if you have an airplane capable of producing twice the amount of thrust as that single jet engine mounted in the back of the car. Understand where I am coming from? The wheels are merely a contact point and are needed to provide control and reduce friction. A plane would not be able to take off very well on a runway while resting on its belly. The free spinning parts allow for this to happen. However, a plane will be able to take off on ice without landing gear. The ice will not provide enough resistance to prevent the plane from taking off or catching on fire. Hell, planes take off from water all the time without landing gear.

I have another interesting idea to consider. Let's say you replaced the wheels of the plane with a flat surface the provides no friction whatsoever. Will the plane move forward with the engines at full throttle? YES! The treadmill will spin freely under this "frictionless" material and will not effect the speed of the plane moving forward. I know this is a lengthy response, but I hope this will eliminate some of the doubts from others who are skeptical about the whole plane vs. treadmill idea. Next time you go to an airport with motorized walkways, bring some rollerskates and hold on to the railing. Then, have a friend behind you try to push you the opposite direction of the motorized sidewalk. You will receive many crazy looks, but you WILL move forward.

This is just my http://forums.importatlanta.com/images/smilies/2cents.gif on this question.

Chris

[SNapper]

lol how is a plane gunna take off without air passing over it's wings?

[speedminded]

lol how is a plane gunna take off without air passing over it's wings?jesus christ people, the conveyor/treadmill IN NO WAY prevents the aircraft from moving forward...it is NO DIFFERANT than a runway.

With that said, how does the airplane get on the conveyor and is it already moving or what? With no problems at all the plane could taxi on to a moving conveyor and in no way would it effect the motion of the airplane...just like if you were on a bicyle and road up to a running treadmill, did a wheelie and put the front wheel on the conveyor belt....would it throw the bicycle backwards? NO Could you continue to ride forward (up to the rear wheel, but not touching the rear wheel)? YES.

In order to ride up on the tread mill you would have to match the rear wheel speed to the treadmills speed, why? because the bicycles rear wheel powers the bicycle...The wheels on a plane DO NOT propel the aircraft.

[swiftblaze]

lol how is a plane gunna take off without air passing over it's wings?

LOL. I'm in a hurry at work and neglected to mention that in my post. The plane will be taking off under the same conditions as those from a stationary runway since all variables will remain the same, and the aircraft does not rely on power to the wheels to take off. The wheels are free spinning and will not slow the planes forward momentum caused by thrust from the jet engines.

[ShooterMcGavin]

READ THE ARTICLE IN THE LINK, answers all your questions, i promise.

[speedminded]

LOL. I'm in a hurry at work an neglected to mention that in my post. The plane will be taking off under the same conditions as those from a stationary runway since all variables will remain the same.Thankyou!

[swiftblaze]

READ THE ARTICLE IN THE LINK, answers all your questions, i promise.

Agreed! :goodjob: