Mythbusters to take on "the plane and the treadmill" conundrum?

[redgtxdi]

Hmmm..............




Well, I still say plane does *not* take off.


Another thing I want to say is "barring propellers creating wind speed over the wings".




An F-16 (which propels thrust out the rear, thus NOT interfering w/ wind-speed dynamics over the wings or body of the plane could push thrust a bazillion mph & still not get off the ground regardless of how much 'flap' or 'up aileron' was induced............UNLESS..............the thrust nozzle was pointed upward creating vertical disposition of thrust & creating rocketed type of takeoff scenario............no???

 

[Tom]

Originally posted by: smack Down

Originally posted by: Linflas

Originally posted by: smack Down

Originally posted by: Rob9874

Originally posted by: Garth
Do you agree that were the nose of the plane tied to an immovable post in front of the treadmill, the plane would remain stationary while the treadmill moved underneath it?

I do, that's a good analogy. And then, would you agree if someone pulled that post forward, it would not also pull the plane forward, even though the treadmill was matching the speed of its wheels?

The plane can't move forward if the treadmill is matching the speed of the wheels. It is impossible to have movement under such a case.

If the motive force causing a plane to move forward was provided at the wheels your statement would be correct. In this same hypothetical situation an automobile absolutely would not move forward since the motive power is applied to the wheels.

No it is simple math.

Lets say the wheel speed is 4 mph. Then the treadmil also must be 4 mph. The net speed is there for zero.
4 -4 = 0. It has nothing to do with where or how force is applied.

The relevant speed of the treadmill is the surface of the treadmill, that is what has to match the wheel speed, not the rotation of the treadmill.

The wheel, and plane, can be stationary relevant to the treadmill surface, and vice-versa, and the plane can move relative to the air, because the treadmill surface can move, relative to the air, too.

And the same thing is true whatever the speed of the wheel is, relative to the surface of the treadmill.

 

[DanTMWTMP]

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down
You can push any object forward on a treadmill at constant speed. If the treadmill is going to match the speed the object moves on it then you can never move the object.

Wrong. There is insufficient friction in the wheels to cause this. As stated, if the treadmill matches the object's forward speed, the wheels simply spin twice as fast for a given groundspeed.

ZV

No as stated the treadmill matches the speed of the object on the treadmill. It does not match the ground speed of the object. Otherwise the car would not have moved.

As long as the wheel are spinning a force is going to be applied to the axel that is porpotional to the speed the wheel is spinning.

Think about it.

If you put a plane on a treadmill and the planes engines are off do you really think it is just going to sit there.

The drag of the landing gear is infinitesimally small. Not enough to consider when compared to the thrust of the engine. If the engine is off, the drag of the landing gear is enough to cause the plane to "ride" the treadmill because there are no other forces acting at the moment. Once the engine is running, it becomes by far the dominant force, easily overcoming the drag of the landing gear. If the engine couldn't overcome the drag of the landing gear, the airplane wouldn't be able to take off even from a normal runway.

ZV

The size of the forces doesn't matter because the treadmill can increase speed infinitly so it can apply an infinite amount of force.

*sigh*

Please don't vote. Or breed.

ZV

Awah how cute have to resort to more lame persional attacks.

well, i don't think he has a choice, because you fail to realize that the plane will indeed fly; so unfortunately, i'm going to have to agree w/ zemmervolt and continue his intention to insult you due to your hubris and ineptude...

the treadmill has no bearing on the plane's engines, which are acting upon the AIR, not the goddamn treadmill. Engines don't give a sh!t about the treadmill. The wheels are free spinning, plane will move at the same rate as it does on any runway, and take off.

/thread.

 

[Cerpin Taxt]

Originally posted by: smack Down

Originally posted by: Rob9874

Originally posted by: Garth
Do you agree that were the nose of the plane tied to an immovable post in front of the treadmill, the plane would remain stationary while the treadmill moved underneath it?

I do, that's a good analogy. And then, would you agree if someone pulled that post forward, it would not also pull the plane forward, even though the treadmill was matching the speed of its wheels?

The plane can't move forward if the treadmill is matching the speed of the wheels. It is impossible to have movement under such a case.

We are not concerned about the speed of the wheels. We are concerned with the speed of the plane. Answer the question.

 

[AbsolutDealage]

Originally posted by: redgtxdi
Hmmm..............




Well, I still say plane does *not* take off.


Another thing I want to say is "barring propellers creating wind speed over the wings".




An F-16 (which propels thrust out the rear, thus NOT interfering w/ wind-speed dynamics over the wings or body of the plane could push thrust a bazillion mph & still not get off the ground regardless of how much 'flap' or 'up aileron' was induced............UNLESS..............the thrust nozzle was pointed upward creating vertical disposition of thrust & creating rocketed type of takeoff scenario............no???

Please tell me you are joking.... you think that the only reason planes take off is the engines pushing air over the wings?

 

[smack Down]

well, i don't think he has a choice, because you fail to realize that the plane will indeed fly; so unfortunately, i'm going to have to agree w/ zemmervolt and continue his intention to insult you due to your hubris and ineptude...

the treadmill has no bearing on the plane's engines, which are acting upon the AIR, not the goddamn treadmill. Engines don't give a sh!t about the treadmill. The wheels are free spinning, plane will move at the same rate as it does on any runway, and take off.

/thread.

Would you care to support the claim that the wheels have no effect or just perfer to pull it out your ass.

Lets consider a stopped plane on a treadmill.
If the treadmill is going 10 mph how fast will the plane move?
If the treadmill is going 100 mph how fast will the plane move?
If the treadmill is going 1000 mph how fast will the plane move?
If the treadmill is going 10000 mph how fast will the plane move?
If the treadmill is going 100000 mph how fast will the plane move?

 

[AbsolutDealage]

Originally posted by: smack Down

Would you care to support the claim that the wheels have no effect or just perfer to pull it out your ass.

Lets consider a stopped plane on a treadmill.
If the treadmill is going 10 mph how fast will the plane move?
If the treadmill is going 100 mph how fast will the plane move?
If the treadmill is going 1000 mph how fast will the plane move?
If the treadmill is going 10000 mph how fast will the plane move?
If the treadmill is going 100000 mph how fast will the plane move?

Keep diggin' that grave. Let us know when you're done.

 

[smack Down]

Originally posted by: AbsolutDealage

Originally posted by: smack Down

Would you care to support the claim that the wheels have no effect or just perfer to pull it out your ass.

Lets consider a stopped plane on a treadmill.
If the treadmill is going 10 mph how fast will the plane move?
If the treadmill is going 100 mph how fast will the plane move?
If the treadmill is going 1000 mph how fast will the plane move?
If the treadmill is going 10000 mph how fast will the plane move?
If the treadmill is going 100000 mph how fast will the plane move?

Keep diggin' that grave. Let us know when you're done.

Well how fast wiill the plane move? Are you one of the people that thinks it can magicaly hover over the treadmill?

 

[kthroyer]

To Rob9874,

You nailed it.

The plane being pulled by a string with the wheels freely spinning is exactly the way people need to visualize this problem. No matter how fast the treadmill rotated you could pull the plane forward with the string, because the force moving the plane forward has zero to do with the interaction of the wheels and the treadmill. The treadmill could be spinning at a zillion mile per hour, and as long as the wheels could spin without friction, you could pull the plane forward with the string.

Some of the replies in here are scary.

 

[OutHouse]

Originally posted by: DanTMWTMP

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down

Originally posted by: Zenmervolt

Originally posted by: smack Down
You can push any object forward on a treadmill at constant speed. If the treadmill is going to match the speed the object moves on it then you can never move the object.

Wrong. There is insufficient friction in the wheels to cause this. As stated, if the treadmill matches the object's forward speed, the wheels simply spin twice as fast for a given groundspeed.

ZV

No as stated the treadmill matches the speed of the object on the treadmill. It does not match the ground speed of the object. Otherwise the car would not have moved.

As long as the wheel are spinning a force is going to be applied to the axel that is porpotional to the speed the wheel is spinning.

Think about it.

If you put a plane on a treadmill and the planes engines are off do you really think it is just going to sit there.

The drag of the landing gear is infinitesimally small. Not enough to consider when compared to the thrust of the engine. If the engine is off, the drag of the landing gear is enough to cause the plane to "ride" the treadmill because there are no other forces acting at the moment. Once the engine is running, it becomes by far the dominant force, easily overcoming the drag of the landing gear. If the engine couldn't overcome the drag of the landing gear, the airplane wouldn't be able to take off even from a normal runway.

ZV

The size of the forces doesn't matter because the treadmill can increase speed infinitly so it can apply an infinite amount of force.

*sigh*

Please don't vote. Or breed.

ZV

Awah how cute have to resort to more lame persional attacks.

well, i don't think he has a choice, because you fail to realize that the plane will indeed fly; so unfortunately, i'm going to have to agree w/ zemmervolt and continue his intention to insult you due to your hubris and ineptude...

the treadmill has no bearing on the plane's engines, which are acting upon the AIR, not the goddamn treadmill. Engines don't give a sh!t about the treadmill. The wheels are free spinning, plane will move at the same rate as it does on any runway, and take off.

/thread.

no wind no airspeed no lift

/thread.

 

[DanTMWTMP]

Originally posted by: smack Down

well, i don't think he has a choice, because you fail to realize that the plane will indeed fly; so unfortunately, i'm going to have to agree w/ zemmervolt and continue his intention to insult you due to your hubris and ineptude...

the treadmill has no bearing on the plane's engines, which are acting upon the AIR, not the goddamn treadmill. Engines don't give a sh!t about the treadmill. The wheels are free spinning, plane will move at the same rate as it does on any runway, and take off.

/thread.

Would you care to support the claim that the wheels have no effect or just perfer to pull it out your ass.

Lets consider a stopped plane on a treadmill.
If the treadmill is going 10 mph how fast will the plane move?
If the treadmill is going 100 mph how fast will the plane move?
If the treadmill is going 1000 mph how fast will the plane move?
If the treadmill is going 10000 mph how fast will the plane move?
If the treadmill is going 100000 mph how fast will the plane move?

the engines have no bearing on the treadmill. it's only purpose is to move air, and not against the treadmill. If a car was on the treadmill, the car would not move foward. If a plane was on it, it will move foward since the engines only care about airspeed, and not groundspeed. If the treadmill is moving 10 mph or 1000000 mph, the plane will still move at the same pace.

Very very simple concept, and nothing is out of my ass, except you are thinking out of your own.

if we go by your logic, then if a guy is holding onto a rope on a treadmill, his arms will tear apart and he'll move backwards.
by your logic, that means if you attach a string to a skateboard, and pull it across the treadmill, you won't be able to pull it? you're pulling it at 5 mph, and the treadmill is moving 5 mph, so, by your logic, the skateboard will stay put eh? right? no. the skateboard will move towards you as you pull the damn thing, and the wheels will just be free spinning.

the rope/string is another force that is ignorant of the ground. the air in which the plane's engine is acting on is ignorant of the ground.

so simple, yet you refuse to believe it. get your own head out of your own ass, dumbass.

 

[JujuFish]

Oh joy, this thread has popped up yet again.

Even in the impossibility of the treadmill matching the wheels' rotational speed rather than the physically possible problem of the treadmill matching the forward motion, the plane can still take off. Everyone accepts the fact that in the physically impossible scenario, infinite forces exist. Good. Now, all the plane has to do to take off is lock its wheels in place with something. The wheels will never move. Since the wheels will never move, the treadmill will also never move. However, the plane will move forward, skidding and bumping along, because of the thrust provided. Since that thrust can be infinite, since everyone agrees in this impossible scenario that these infinite forces exist, nothing will be opposing the plane except a smaller frictional force caused from the skidding. The plane will accelerate and take off.

On a side note, I hope for the sake of humanity that we can all agree that in the scenario where the treadmill matches the forward movement of the plane that the plane takes off.

 

[smack Down]

Originally posted by: DanTMWTMP
Blah, Blah Blah.

What would be the speed of a plane on a treadmill if its engine is stopped? ie the plane is off?

If the treadmill is going 10 mph how fast will the plane move?
If the treadmill is going 100 mph how fast will the plane move?
If the treadmill is going 1000 mph how fast will the plane move?
If the treadmill is going 10000 mph how fast will the plane move?
If the treadmill is going 100000 mph how fast will the plane move?

 

[LS20]

Originally posted by: Zenmervolt
OK, REGARDLESS of treadmill speed, the airplane moves forward. The thrust comes from Newton's 3rd law (every action has an equal and opposite reaction) and since the engines of the plane push the air backwards, the airplane is in turn thrust forwards. The entire treadmill part is a very cleaver red-herring that gives an excellent example of an area where traditional logic fails.

The first premise of the situation, that the treadmill always compensates for the plane's forward motion, is simply not possible. Ever. Given the manner in which a plane achieves forward motion it is not, and will never be, physically possible to have a treadmill that compensates for the plane's thrust. It violates the basic laws of physics.
ZV

okay, take the wheels away from the plane, have its belly resting on the ground. turn on thrusters. what happens? SCRAPE SCRAPE SCRAPE. all this talk about physics and elementary school - where does gravity come into play?

 

[AbsolutDealage]

Originally posted by: smack Down
Well how fast wiill the plane move? Are you one of the people that thinks it can magicaly hover over the treadmill?

OK, well, let's go with that then. What if you were to design a plane that had a big hovercraft cushion on the bottom instead of wheels. It sits on a cushion of air over a treadmill that will match the plane's groundspeed. Will it take off?

Now, do you realize that it is the exact same scenario?

 

[Midlander]

The ignorance in this thread is staggering and disappointing. Either that or a couple of you are just trolling. <backs out of thread> :beer:

 

[randay]

Originally posted by: LS20

Originally posted by: Zenmervolt
OK, REGARDLESS of treadmill speed, the airplane moves forward. The thrust comes from Newton's 3rd law (every action has an equal and opposite reaction) and since the engines of the plane push the air backwards, the airplane is in turn thrust forwards. The entire treadmill part is a very cleaver red-herring that gives an excellent example of an area where traditional logic fails.

The first premise of the situation, that the treadmill always compensates for the plane's forward motion, is simply not possible. Ever. Given the manner in which a plane achieves forward motion it is not, and will never be, physically possible to have a treadmill that compensates for the plane's thrust. It violates the basic laws of physics.
ZV

okay, take the wheels away from the plane, have its belly resting on the ground. turn on thrusters. what happens? SCRAPE SCRAPE SCRAPE. all this talk about physics and elementary school - where does gravity come into play?

It comes into play when certain people got dropped on thier heads as babies?

 

[Number1]

Has anybody in the "it will not fly" camp read sao123's post? That would be a start to get a good understanding of the problem and it?s solution.
The speed of the plane is in relation to the ground. If the plane is not moving in relation to the ground, the treadmill is not moving. If the plane is moving at 25 MPH in relation to the ground, the treadmill is moving at 25 MPH in the opposite direction. The prop moves the plane trough the air. The treadmill rotates the wheels. The plane accelerates and takes off.

 

[LS20]

Originally posted by: Zenmervolt
As explained a half-dozen times already, the plane does not remain stationary.

ZV

put a toy plane -- or toy car -- on a real treadmill. turn treadmill on. where does car go? belt brings car backwards

now place your finger on the rear bumper of the car (or plane). now there are opposing forces (car vs finger) just like plane scenario (thrust)... where does car go?

 

[smack Down]

Originally posted by: Number1
Has anybody in the "it will not fly" camp read sao123's post? That would be a start to get a good understanding of the problem and it?s solution.
The speed of the plane is in relation to the ground. If the plane is not moving in relation to the ground, the treadmill is not moving. If the plane is moving at 25 MPH in relation to the ground, the treadmill is moving at 25 MPH in the opposite direction. The prop moves the plane trough the air. The treadmill rotates the wheels. The plane accelerates and takes off.

Just cause saso123 failed to read the post describing the situation doesn't the rest of us did.

 

[Linflas]

Originally posted by: LS20

Originally posted by: Zenmervolt
OK, REGARDLESS of treadmill speed, the airplane moves forward. The thrust comes from Newton's 3rd law (every action has an equal and opposite reaction) and since the engines of the plane push the air backwards, the airplane is in turn thrust forwards. The entire treadmill part is a very cleaver red-herring that gives an excellent example of an area where traditional logic fails.

The first premise of the situation, that the treadmill always compensates for the plane's forward motion, is simply not possible. Ever. Given the manner in which a plane achieves forward motion it is not, and will never be, physically possible to have a treadmill that compensates for the plane's thrust. It violates the basic laws of physics.
ZV

okay, take the wheels away from the plane, have its belly resting on the ground. turn on thrusters. what happens? SCRAPE SCRAPE SCRAPE. all this talk about physics and elementary school - where does gravity come into play?

Gravity is what is overcome by lift. If the engines had sufficient thrust to overcome the friction of the plane directly on the ground the plane would take off. The original Wright Flyer did not have wheels yet it managed to get off the ground by traveling along a rail.

 

[Rob9874]

Originally posted by: LS20

Originally posted by: Zenmervolt
As explained a half-dozen times already, the plane does not remain stationary.

ZV

put a toy plane -- or toy car -- on a real treadmill. turn treadmill on. where does car go? belt brings car backwards

now place your finger on the rear bumper of the car (or plane). now there are opposing forces (car vs finger) just like plane scenario (thrust)... where does car go?

Now, use that finger to push the car forward (more thrust), where does the car go?

 

[AbsolutDealage]

Originally posted by: smack Down

Originally posted by: Number1
Has anybody in the "it will not fly" camp read sao123's post? That would be a start to get a good understanding of the problem and it?s solution.
The speed of the plane is in relation to the ground. If the plane is not moving in relation to the ground, the treadmill is not moving. If the plane is moving at 25 MPH in relation to the ground, the treadmill is moving at 25 MPH in the opposite direction. The prop moves the plane trough the air. The treadmill rotates the wheels. The plane accelerates and takes off.

Just cause saso123 failed to read the post describing the situation doesn't the rest of us did.

Since you are so apt to point out other people not answering questions, what about my hovercraft scenario above?

 

[OutHouse]

Originally posted by: Number1
Has anybody in the "it will not fly" camp read sao123's post? That would be a start to get a good understanding of the problem and it?s solution.
The speed of the plane is in relation to the ground. If the plane is not moving in relation to the ground, the treadmill is not moving. If the plane is moving at 25 MPH in relation to the ground, the treadmill is moving at 25 MPH in the opposite direction. The prop moves the plane trough the air. The treadmill rotates the wheels. The plane accelerates and takes off.

i read it and it still does not explain where the wind comes from to get that lift. if the plane is going 25mph west and the treadmill is going 25mph east the plane is not moving. sure the wheels are but the plane is staying in one spot. how hard is that to understand???

 

[smack Down]

Originally posted by: AbsolutDealage

Originally posted by: smack Down

Originally posted by: Number1
Has anybody in the "it will not fly" camp read sao123's post? That would be a start to get a good understanding of the problem and it?s solution.
The speed of the plane is in relation to the ground. If the plane is not moving in relation to the ground, the treadmill is not moving. If the plane is moving at 25 MPH in relation to the ground, the treadmill is moving at 25 MPH in the opposite direction. The prop moves the plane trough the air. The treadmill rotates the wheels. The plane accelerates and takes off.

Just cause saso123 failed to read the post describing the situation doesn't the rest of us did.

Since you are so apt to point out other people not answering questions, what about my hovercraft scenario above?

How about we stick to the case at hand. If you wish to expand on your hover craft or what ever so that it makes sence go for it. But I think there are already way to many other bad comparisions in this thread.