MythBusters

[sdifox]

Originally posted by: jandrews

Originally posted by: pnad
The plane is NOT stationary. That is the point. The treadmill is incapable of keeping a plane stationary.

so when you are running on a treadmill you feel the wind picking up and blowing in your face when at the gym? lmao, uh no.

when you are running on a treadmill, you are using your legs pushing against the treadmill to generate forward momentum. Planes don't do the same thing.

 

[jandrews]

Originally posted by: sdifox

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: HydroSqueegee
The plane is not going forward, therefore no air is passing over/under the wings which equals no lift. It will not take off. There is simply nothing there to LIFT it.

Here are two ways to think about it:

1) Imagine a car on a treadmill. The car derives the force necessary to move it forward by the tires spinning and friction with the ground. Put a car on this mythical treadmill and it won't move forward - right? The faster the wheels spin, the faster the treadmill spins. No movement.

Why isn't this true of a plane? A plane does not push against the ground to move forward. The jets, props, whatever push against the air around the plane. Think about sea planes. They take off and land on the water and don't have anything to propel them through the water. The wheels are only attached to a plane to reduce friction between the plane and the ground - they don't actually propel the plane at all.

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

Let me know if you'd like further clarification. I'll do my best to explain.

I dont know if you just dont understand but you are not answering his question at all. He is saying that a plane will not take off because there is no air moving under the wings to provide lift regardless of the propulsion of the jet engines.

All your answers respond to someone stating that jet engines dont do much and the wheels are a factor but dont address his comments at all.

A better more simple question would be why do planes have wings at all? According to people who say the engines provide all the lift why not just make a plane that is submarine shaped (taking turning out of the equation of course).

How is the treadmill going to keep the plane static? air is being sucked into the jet engine and pushed out back, the wheel is there to keep the plane from hitting ground, not to propel it.

From my understanding, the treadmill will keep the plane from continuing in a forward motion. The wheels will spin and the treadmill will keep pace with the wheels thus the plane will appear stationary, correct? The wheels are not the propulsion obviously but they do give the plane the medium to increase speed and wind resistance under the wings to allow for an effective takeoff.

 

[BeauJangles]

Originally posted by: jandrews

Originally posted by: dainthomas

Originally posted by: jandrews

Originally posted by: pnad
The plane is NOT stationary. That is the point. The treadmill is incapable of keeping a plane stationary.

so when you are running on a treadmill you feel the wind picking up and blowing in your face when at the gym? lmao, uh no.

If I was wearing a jet pack and wearing roller skates I would.

So, am I correct in understanding that you believe that someone who is on a treadmill where the track moves under them will somehow work up wind resistance when they reach a certain speed? I cannot even explain how insane that sounds. I feel like I am in the twilight zone where everyone else is crazy and I am the only sane one but they all believe they are sane. I dont care what you say, there is no way that an object on wheels that remains in the same position as it started will build up wind resistance.

Read my post above.

When you run on a treadmill, you push yourself forward via friction with the ground. That is not true for an airplane, which pushes itself forward by 'pushing' on the air behind it. The plane's wheels would not stay in the same place as the forward thrust from the engines would move the plane.

Again, read my post above. I think I've laid it out pretty well.

 

[pnad]

A stationary object will not fly, you are 100% correct.

The point is, as I stated earlier, a treadmill cannot keep a plane stationary. The plane WILL move forward. Did you even watch the youtube vid that was posted?

Do you have a treadmill and rollerblades?
Get on that thing and pull yourself forward with it turned off.
Now set it to 5mph and try again.
Now again at 10mph.
Did you move forward? (yes)
Did you notice an increase in forced required to move you forward? (no)

 

[jandrews]

Originally posted by: pnad
A stationary object will not fly, you are 100% correct.

The point is, as I stated earlier, a treadmill cannot keep a plane stationary. The plane WILL move forward. Did you even watch the youtube vid that was posted?

Do you have a treadmill and rollerblades?
Get on that thing and pull yourself forward with it turned off.
Now set it to 5mph and try again.
Now again at 10mph.
Did you move forward? (yes)
Did you notice an increase in forced required to move you forward? (no)

In all fairness, a treadmill has quite a bit of restraint on its spinning belt. So from my understanding the whole argument for the plane taking off is that even on a conveyor belt the plane will still move forward? If this is the argument, I will concur with that sentiment.

On the other hand, there are a lot of variables here. The 'looseness' of the conveyor belt is unknown and a driving factor. If the conveyor belt easily moves then the plane would never get forward momentum and the wind resistance to take off. The wheels would spin, the plane would stay in place, there would be no wind resistance and the plane would not take off.

Regardless, I think mythbusters is going to do the myth in a way that will leave nearly everybody dissatisifed and the argument will go on. Apparently the argument is more about variables than anything.

From my understanding the wheels would be rubber on the plane and the track would be rubber. The plane starts very slow and is very heavy and the treadmill would be able to keep pace. I am not a person who thinks that they would initially have a motor powered treadmill that set the pace.

 

[purbeast0]

do you feel wind in your face when you are running on a treadmill?

no.

there is no air under the wings to cause lift off.

the plane is not going to take off.

EDIT:

if this whole debate is about the plane physically moving from point A to point B on a huge ass treadmill, then yes I think it can take off.

if the plane is stationary on a treadmill at point A, it will not take off.

I had always assumed it was about the latter.

 

[BeauJangles]

Originally posted by: purbeast0
do you feel wind in your face when you are running on a treadmill?

no.

there is no air under the wings to cause lift off.

the plane is not going to take off.

from my above post:

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

edit: Think about it this way, if the plane wouldn't take off on a conveyor belt because the wheels aren't spinning, then how does it fly in the air? The wheels don't spin there either. Easy, the plane flies through the air because the jets or props push against the air, moving the plane forward. The plane moves through the air at a high enough speed to generate lift across the wings and it flies.

 

[jandrews]

Originally posted by: BlinderBomber

Originally posted by: purbeast0
do you feel wind in your face when you are running on a treadmill?

no.

there is no air under the wings to cause lift off.

the plane is not going to take off.

from my above post:

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

edit: Think about it this way, if the plane wouldn't take off on a conveyor belt because the wheels aren't spinning, then how does it fly in the air? The wheels don't spin there either. Easy, the plane flies through the air because the jets or props push against the air, moving the plane forward. The plane moves through the air at a high enough speed to generate lift across the wings and it flies.

I understand what you are saying but the problem is there is no seperate force for the plane. The only force is the engines, I am saying the treadmill has no motor powering it and the planes motion and grip on the wheels is what makes it move.

 

[dainthomas]

Originally posted by: jandrews

Originally posted by: dainthomas

Originally posted by: jandrews

Originally posted by: pnad
The plane is NOT stationary. That is the point. The treadmill is incapable of keeping a plane stationary.

so when you are running on a treadmill you feel the wind picking up and blowing in your face when at the gym? lmao, uh no.

If I was wearing a jet pack and wearing roller skates I would.

So, am I correct in understanding that you believe that someone who is on a treadmill where the track moves under them will somehow work up wind resistance when they reach a certain speed? I cannot even explain how insane that sounds. I feel like I am in the twilight zone where everyone else is crazy and I am the only sane one but they all believe they are sane. I dont care what you say, there is no way that an object on wheels that remains in the same position as it started will build up wind resistance.

This is where you are confused. A treadmill cannot keep an object on wheels in the same position.

Unless you have a magical infinite treadmill. As was stated in the previous thread, the magical infinite treadmill assumption also requires the magical frictionless wheels assumption in which case it still moves forward.

 

[JujuFish]

Originally posted by: jandrews
If the conveyor belt easily moves then the plane would never get forward momentum and the wind resistance to take off.

Uh, wrong. The conveyor belt could spin twice as fast as the plane needs to take off and the plane will still move forward and take off.

 

[BeauJangles]

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: purbeast0
do you feel wind in your face when you are running on a treadmill?

no.

there is no air under the wings to cause lift off.

the plane is not going to take off.

from my above post:

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

edit: Think about it this way, if the plane wouldn't take off on a conveyor belt because the wheels aren't spinning, then how does it fly in the air? The wheels don't spin there either. Easy, the plane flies through the air because the jets or props push against the air, moving the plane forward. The plane moves through the air at a high enough speed to generate lift across the wings and it flies.

I understand what you are saying but the problem is there is no seperate force for the plane. The only force is the engines, I am saying the treadmill has no motor powering it and the planes motion and grip on the wheels is what makes it move.

I think you're confused.

The only force is the engines

If the only force is the engines what are they pushing against to generate forward motion? - it can't be the ground because those same engines propel the plane through the air when it's flying. You're thinking about this problem as if a plane works just like a car, which it doesn't.

Without friction, the treadmill could move at 1,000,000 miles per hour and the plane would still take off. Even with friction, the plane would take off until the friction of the spinning wheels inhibited the plane from achieving its liftoff speed.

 

[ElFenix]

obviously the plane's wheel bearings overheat and seize and the plane explodes.

 

[Jeff7]

Originally posted by: ElFenix
obviously the plane's wheel bearings overheat and seize and the plane explodes.

Maybe a bird (or Adam Savage) flies into one of the engines.

 

[JoLLyRoGer]

Originally posted by: jandrews

Originally posted by: sdifox

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: HydroSqueegee
The plane is not going forward, therefore no air is passing over/under the wings which equals no lift. It will not take off. There is simply nothing there to LIFT it.

Here are two ways to think about it:

1) Imagine a car on a treadmill. The car derives the force necessary to move it forward by the tires spinning and friction with the ground. Put a car on this mythical treadmill and it won't move forward - right? The faster the wheels spin, the faster the treadmill spins. No movement.

Why isn't this true of a plane? A plane does not push against the ground to move forward. The jets, props, whatever push against the air around the plane. Think about sea planes. They take off and land on the water and don't have anything to propel them through the water. The wheels are only attached to a plane to reduce friction between the plane and the ground - they don't actually propel the plane at all.

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

Let me know if you'd like further clarification. I'll do my best to explain.

I dont know if you just dont understand but you are not answering his question at all. He is saying that a plane will not take off because there is no air moving under the wings to provide lift regardless of the propulsion of the jet engines.

All your answers respond to someone stating that jet engines dont do much and the wheels are a factor but dont address his comments at all.

A better more simple question would be why do planes have wings at all? According to people who say the engines provide all the lift why not just make a plane that is submarine shaped (taking turning out of the equation of course).

How is the treadmill going to keep the plane static? air is being sucked into the jet engine and pushed out back, the wheel is there to keep the plane from hitting ground, not to propel it.

From my understanding, the treadmill will keep the plane from continuing in a forward motion. The wheels will spin and the treadmill will keep pace with the wheels thus the plane will appear stationary, correct? The wheels are not the propulsion obviously but they do give the plane the medium to increase speed and wind resistance under the wings to allow for an effective takeoff.

NO, FALSE!!!

The wheels are not the medium the plane uses to increase speed! That's what the engines are for!!! Suck-Bang-Blow. That's it!! A plane does not even need wheels to take off under the right conditions!

Wheels and treadmills mean NOTHING - C'mon and say it with me - they mean NOTHING to a JET or a Turboprop aircraft engine. These devices use the air as their meduim to gain momentum the same way a sub-marine pushes its self through the water. Cars, Dogs, and People all use the ground as their medium.

Let me break it down for you:
Cars and Trucks push against the ground (with help from gravitiy providing downforce) - That is their medium

Boats and Subs push agains the water.

Planes push against the AIR - That's IT! AIR is the medium, not the Goddamn wheels on the Goddamn plane!

Am I getting through to you??

 

[ThePresence]

Planes can take off with skis on ice.

/thread

 

[sdifox]

Originally posted by: BlinderBomber

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: purbeast0
do you feel wind in your face when you are running on a treadmill?

no.

there is no air under the wings to cause lift off.

the plane is not going to take off.

from my above post:

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

edit: Think about it this way, if the plane wouldn't take off on a conveyor belt because the wheels aren't spinning, then how does it fly in the air? The wheels don't spin there either. Easy, the plane flies through the air because the jets or props push against the air, moving the plane forward. The plane moves through the air at a high enough speed to generate lift across the wings and it flies.

I understand what you are saying but the problem is there is no seperate force for the plane. The only force is the engines, I am saying the treadmill has no motor powering it and the planes motion and grip on the wheels is what makes it move.

I think you're confused.

The only force is the engines

If the only force is the engines what are they pushing against to generate forward motion? - it can't be the ground because those same engines propel the plane through the air when it's flying. You're thinking about this problem as if a plane works just like a car, which it doesn't.

Without friction, the treadmill could move at 1,000,000 miles per hour and the plane would still take off. Even with friction, the plane would take off until the friction of the spinning wheels inhibited the plane from achieving its liftoff speed.

Forward motion is generated by the opposite force of the jet exhaust, AKA thrust.

http://travel.howstuffworks.co...sa.gov/Engines101.html

 

[jandrews]

Originally posted by: JoLLyRoGer

Originally posted by: jandrews

Originally posted by: sdifox

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: HydroSqueegee
The plane is not going forward, therefore no air is passing over/under the wings which equals no lift. It will not take off. There is simply nothing there to LIFT it.

Here are two ways to think about it:

1) Imagine a car on a treadmill. The car derives the force necessary to move it forward by the tires spinning and friction with the ground. Put a car on this mythical treadmill and it won't move forward - right? The faster the wheels spin, the faster the treadmill spins. No movement.

Why isn't this true of a plane? A plane does not push against the ground to move forward. The jets, props, whatever push against the air around the plane. Think about sea planes. They take off and land on the water and don't have anything to propel them through the water. The wheels are only attached to a plane to reduce friction between the plane and the ground - they don't actually propel the plane at all.

2) Imagine you're on a treadmill with roller blades. (let's assume there is no friction) When you turn on the treadmill to 5 mph your wheels will spin at 5 mph and you will go nowhere, right? Increase speed as much as you want, but your feet won't move at all. Now, imagine there is a rope attached to the wall in front of you. When you grab the rope and pull, what happens? You move forward. Why? Because the force of the rope is independent of the forces acting on the wheels on your roller blades. A jet engine works the same way. It acts completely independently of anything going on underneath it.

Let me know if you'd like further clarification. I'll do my best to explain.

I dont know if you just dont understand but you are not answering his question at all. He is saying that a plane will not take off because there is no air moving under the wings to provide lift regardless of the propulsion of the jet engines.

All your answers respond to someone stating that jet engines dont do much and the wheels are a factor but dont address his comments at all.

A better more simple question would be why do planes have wings at all? According to people who say the engines provide all the lift why not just make a plane that is submarine shaped (taking turning out of the equation of course).

How is the treadmill going to keep the plane static? air is being sucked into the jet engine and pushed out back, the wheel is there to keep the plane from hitting ground, not to propel it.

From my understanding, the treadmill will keep the plane from continuing in a forward motion. The wheels will spin and the treadmill will keep pace with the wheels thus the plane will appear stationary, correct? The wheels are not the propulsion obviously but they do give the plane the medium to increase speed and wind resistance under the wings to allow for an effective takeoff.

NO, FALSE!!!

The wheels are not the medium the plane uses to increase speed! That's what the engines are for!!! Suck-Bang-Blow. That's it!! A plane does not even need wheels to take off under the right conditions!

Wheels and treadmills mean NOTHING - C'mon and say it with me - they mean NOTHING to a JET or a Turboprop aircraft engine. These devices use the air as their meduim to gain momentum the same way a sub-marine pushes its self through the water. Cars, Dogs, and People all use the ground as their medium.

Let me break it down for you:
Cars and Trucks push against the ground (with help from gravitiy providing downforce) - That is their medium

Boats and Subs push agains the water.

Planes push against the AIR - That's IT! AIR is the medium, not the Goddamn wheels on the Goddamn plane!

Am I getting through to you??

hahaha, oh man I love when people get so riled up about this, I can understand because a few pages ago I was calling people names myself!

For the examples given with the given variables I agree. If a plane was on a treadmill it would eventually supercede the speed of the treadmill and take off.

If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

I think the big argument people have is they consider the plane will remain stationary due to the treadmill picking up the speed and not allowing the plane to get any wind resistance. I think people overlook this point and think that other people just dont understand when if it was explained to most people in that manner the debate would be over.

Should still be interesting to see them test.

 

[BeauJangles]

Originally posted by: jandrews
If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

Explain. What is an "infinite" treadmill?

 

[jandrews]

Originally posted by: BlinderBomber

Originally posted by: jandrews
If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

Explain. What is an "infinite" treadmill?

a treadmill that has a starting point but no ending point.

 

[BeauJangles]

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: jandrews
If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

Explain. What is an "infinite" treadmill?

a treadmill that has a starting point but no ending point.

If that's what he means then, no, it doesn't matter. The treadmill could be 200 miles long and the plane would still take off. The only thing that would stop the plane taking off would be the force of friction, if it became great enough.

 

[JujuFish]

Originally posted by: jandrews
I think the big argument people have is they consider the plane will remain stationary due to the treadmill picking up the speed and not allowing the plane to get any wind resistance. I think people overlook this point and think that other people just dont understand when if it was explained to most people in that manner the debate would be over.

Uh, no. We realize that's exactly what people think. Have you not been reading anything at all? Everyone's been trying to explain just why the plane would NOT be stationary.

 

[jandrews]

Originally posted by: BlinderBomber

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: jandrews
If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

Explain. What is an "infinite" treadmill?

a treadmill that has a starting point but no ending point.

If that's what he means then, no, it doesn't matter. The treadmill could be 200 miles long and the plane would still take off. The only thing that would stop the plane taking off would be the force of friction, if it became great enough.

what do you imply by the force of friction? A plane that can gain no windspeed wont take off and isnt that what a infinetely long treadmill would be able to take away from it? This is considering it is a standard 747 with standard engines and a treadmill that would match the speed of the planes wheels causing it to remain in place.

 

[jandrews]

Originally posted by: JujuFish

Originally posted by: jandrews
I think the big argument people have is they consider the plane will remain stationary due to the treadmill picking up the speed and not allowing the plane to get any wind resistance. I think people overlook this point and think that other people just dont understand when if it was explained to most people in that manner the debate would be over.

Uh, no. We realize that's exactly what people think. Have you not been reading anything at all? Everyone's been trying to explain just why the plane would NOT be stationary.

Sure I have, it is becoming evident to me that you have not been reading anything because you missed my entire post saying why I thought the way I thought and the progression to understanding what other people meant.

 

[BlackTigers]

Originally posted by: jandrewstandard 747 with standard engines and a treadmill that would match the speed of the planes wheels causing it to remain in place.

What do you think is making the wheels spin?

 

[BeauJangles]

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: jandrews

Originally posted by: BlinderBomber

Originally posted by: jandrews
If somehow there was somehow an infinite treadmill with no friction the plane would not take off.

Explain. What is an "infinite" treadmill?

a treadmill that has a starting point but no ending point.

If that's what he means then, no, it doesn't matter. The treadmill could be 200 miles long and the plane would still take off. The only thing that would stop the plane taking off would be the force of friction, if it became great enough.

what do you imply by the force of friction? A plane that can gain no windspeed wont take off and isnt that what a infinetely long treadmill would be able to take away from it? This is considering it is a standard 747 with standard engines and a treadmill that would match the speed of the planes wheels causing it to remain in place.

I'd encourage you to read through my posts again, but I'll be happy to keep trying to explain it.

Can you answer the following questions for me:

Imagine we took an airplane and hung it on a huge sling. The landing gear is deployed, but not touching anything. Now the pilot turns on the jets. What will happen?

A sea plane is sitting on a lake. The pilot fires up the engine. What happens?