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Topic: Direct Down Wind Faster Than The Wind (Read 21043 times) previous topic - next topic

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Re: Direct Down Wind Faster Than The Wind
Reply #2175
To spin a wheel, the belt MUST deform into an arc at the bottom of the wheel, regardless of whether there is any wheel deformation or not, as I said earlier.

To roll on a surface, the wheel MUST deform where it meets the surface, regardless of whether or not there is any surface deformation.
Can a surface spin a wheel? Can a wheel roll on a belt?

Re: Direct Down Wind Faster Than The Wind
Reply #2176
In real life there cannot ever be a precise "contact point".  Even two "point particles" interact at a distance, because they interact via forces with non-zero range and because their quantum wavefunctions cannot never be perfectly localized in position.

Of course, none of that matters for the cart.  Heinz, you really think there is a difference in the wheel/surface deformation between a cart on a treadmill in still air, and a cart on a "road" made out of treadmill belt in a steady wind?  That would violate relativity of motion.

Re: Direct Down Wind Faster Than The Wind
Reply #2177
In real life there cannot ever be a precise "contact point".  Even two "point particles" interact at a distance, because they interact via forces with non-zero range and because their quantum wavefunctions cannot never be perfectly localized in position.

Of course, none of that matters for the cart.  Heinz, you really think there is a difference in the wheel/surface deformation between a cart on a treadmill in still air, and a cart on a "road" made out of treadmill belt in a steady wind?  That would violate relativity of motion.


What, exactly do you mean by "relativity of motion"?
I suppose you mean Galilean relativity, which refers only to uniform linear motion.
First, let us consider the case of the cart on the treadmill. The belt is driving the wheels and transferring energy to the wheels. In order to do this, the belt must deform into an arc, however small that arc may be, because point contact cannot spin the wheels, as you seem to know.
When that arc is formed, the force acting on the wheel can be resolved into two components:
1)   The tangential force, which acts to turn the wheel
2)   The radial reaction force, which acts to push the wheel away from the belt
You can see these force components clearly in this diagram:
The image is inverted with the belt at the top, but everything is valid.



Initially, the cart is held down on the belt, to get the wheels and propeller spinning, and the act of holding the cart down overcomes the reaction force. But, once the cart is released, the reaction force will push the wheels away from the belt, causing a loss of traction.
 With reduced traction, propeller thrust briefly exceeds wheel brake force and the cart can advance on the belt. But, whatever goes up must come back down, and the wheels will once again make contact, briefly, with the belt and the cart regains some or all of the energy used in the brief advance up the belt. This results in a cyclic action of the cart periodically advancing during reduction in wheel drag and periodically regaining traction and recovering energy. The cart literally oscillates up the belt by intermittently losing and gaining traction.
There is no reason to think this type of motion is covered by Galilean relativity, which is only concerned with uniform linear motion.
If you place this cart on a road in a wind that is moving at the same speed as the treadmill belt was, what basis do you have for thinking the cart will behave the same way it did on the belt?
Galilean relative motion says nothing about these two very different situations and it is only the illusion of relative motion which has totally confused and fooled everyone, except for a very few people, myself included.
If you think the cart's motion on the road in the wind must be the same as it is on the treadmill, I would appreciate your explanation of why you think that.

I am glad to see you taking an interest in this thread.

Do you think the experiment with the balloons should be done or not?
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2178
Heinz apparently thinks a treadmill belt somehow functions as both a pulley cable and a perpetual-motion trampoline. Is there anything treadmills can't do?

ETA: Other than act as a moving surface, which is the one thing they are actually designed to do. Heinz apparently thinks they are ironically astonishingly bad at that!

Re: Direct Down Wind Faster Than The Wind
Reply #2179
Heinz apparently thinks a treadmill belt somehow functions as both a pulley cable and a perpetual-motion trampoline. Is there anything treadmills can't do?

ETA: Other than act as a moving surface, which is the one thing they are actually designed to do. Heinz apparently thinks they are ironically astonishingly bad at that!

You don't know what i think. You don't even know what you think, if you think at all.
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2180
Well I did say "apparently." But you do keep comparing the wheel resting on the treadmill to a pulley. For example, here:
In fact, any wheel deformation will make it much more difficult for the belt to spin the wheel.


Why?

Try spinning a brick with a belt and see for yourself.

Engineers go to great lengths to see that pulleys are as round as possible and usually made of rigid metal.

Pulley deformation is unwanted. Can you even guess why?
And you also have said...
Initially, the cart is held down on the belt, to get the wheels and propeller spinning, and the act of holding the cart down overcomes the reaction force. But, once the cart is released, the reaction force will push the wheels away from the belt, causing a loss of traction.
 With reduced traction, propeller thrust briefly exceeds wheel brake force and the cart can advance on the belt. But, whatever goes up must come back down, and the wheels will once again make contact, briefly, with the belt and the cart regains some or all of the energy used in the brief advance up the belt. This results in a cyclic action of the cart periodically advancing during reduction in wheel drag and periodically regaining traction and recovering energy.
That certainly sounds like a perpetual-motion trampoline. Why wouldn't it eventually stop losing traction?

And as far as the part about it functioning as a moving surface, you sure don't seem eager to analyze it as such.

Re: Direct Down Wind Faster Than The Wind
Reply #2181
Well I did say "apparently." But you do keep comparing the wheel resting on the treadmill to a pulley. For example, here:
In fact, any wheel deformation will make it much more difficult for the belt to spin the wheel.


Why?

Try spinning a brick with a belt and see for yourself.

Engineers go to great lengths to see that pulleys are as round as possible and usually made of rigid metal.

Pulley deformation is unwanted. Can you even guess why?
And you also have said...
Initially, the cart is held down on the belt, to get the wheels and propeller spinning, and the act of holding the cart down overcomes the reaction force. But, once the cart is released, the reaction force will push the wheels away from the belt, causing a loss of traction.
 With reduced traction, propeller thrust briefly exceeds wheel brake force and the cart can advance on the belt. But, whatever goes up must come back down, and the wheels will once again make contact, briefly, with the belt and the cart regains some or all of the energy used in the brief advance up the belt. This results in a cyclic action of the cart periodically advancing during reduction in wheel drag and periodically regaining traction and recovering energy.
That certainly sounds like a perpetual-motion trampoline. Why wouldn't it eventually stop losing traction?

And as far as the part about it functioning as a moving surface, you sure don't seem eager to analyze it as such.

How is it perpetual motion when it is all driven by a motor on the treadmill?
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2182
A motor that's making the belt go sideways. Not up and down.

Re: Direct Down Wind Faster Than The Wind
Reply #2183
What, exactly do you mean by "relativity of motion"?
I suppose you mean Galilean relativity, which refers only to uniform linear motion.

Either that or special relativity, which also refers to linear motion.  What both say is the following:  given a solution to the laws of physics (i.e. a possible physical process), you can act on it with a transformation that shifts the velocity of everything by some amount (fixed and simply additive for Galilean transforms), and the result is another solution (i.e. another possible physical process).

Now, consider a very long treadmill moving under still air, with a cart slowly advancing up the belt at speed v.  The belt moves at speed w.  Act with the Galilean transform that brings the top surface of the belt to rest.  The new situation is a cart moving at speed w + v, that much is indisputable (it's just the definition of the transform).  The top surface of the belt is at rest in the new frame, while the air is moving over it at speed w.  Therefore this is, at least by some reasonable definitions, an instance of dead dwfttw. 

It would help if you could clarify precisely where you think the above is incorrect.

Quote
Do you think the experiment with the balloons should be done or not?

The original Blackbird run had streamers attached that showed the relative wind direction, and it certainly looked to me that they reversed.  Furthermore GPS data showed the speed and direction and it clearly exceeded windspeed.  With that said, sure, it would be fun to see it chase down some balloons.

  • Brother Daniel
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Re: Direct Down Wind Faster Than The Wind
Reply #2184
Amusing to see Heinz still plugging his moronic "cyclic" fantasy.
Your cyclic hypothesis has been thoroughly debunked.  You seem to think that by repeating it over and over again, you can magically transform it from something stupid into something true.
Oh? Where and when did this "debunking" happen? Please provide a link.
You could start with this demonstration that your arguments for it are self-contradictory.

  • MikeB
Re: Direct Down Wind Faster Than The Wind
Reply #2185
............
To spin a wheel, the belt MUST deform into an arc at the bottom of the wheel, regardless of whether there is any wheel deformation or not, as I said earlier.

To roll on a surface, the wheel MUST deform where it meets the surface, regardless of whether or not there is any surface deformation.
Heinz, this is the same misconception you have been peddling for a long time and I'm pretty sure where you were introduced to it.

You considered the case where you have a rotating shaft with a pulley or wheel, and you want to transmit power to it via a belt.  The wheel is fixed in place and the moving belt has to be brought into contact with it, with some pressure, to create enough friction against the wheel to rotate it, especially with any significant torque.  In this case even the slightest pressure against the wheel will deform the belt (locally curve it) and may have to be significant in order to transmit force / power.  So to transmit any torque to the wheel, make the wheel turn, the belt has to deform.

Then you have been claiming that this is equivalent to a wheel rolling on a surface, and that a treadmill belt has to act the same as what I described above.  This is nonsense; a treadmill belt is backed up by a smooth, flat surface and does not have to deform at all against a wheel to transmit torque to it.  The flat backing provides the force, not the belt tension wrapping around a wheel as with some farm implement.
To roll on a firm surface, a wheel need not have any specific deformation, this is a bizarre idea.  A wheel can have lots of deformation, creating plenty of rolling resistance and also energy loss due to the hysteresis involved in rubber flexing.  Or it can be nearly infinitely rigid against a similar surface, with the least rolling resistance and energy loss.

Balloons anyone?

  • MikeB
Re: Direct Down Wind Faster Than The Wind
Reply #2186
...... With that said, sure, it would be fun to see it chase down some balloons.
Yes it would!  I see a modest chance of that happening this Saturday although proper video with a cell phone may be the biggest challenge.

  • F X
  • The one and only
Re: Direct Down Wind Faster Than The Wind
Reply #2187
To roll on a firm surface, a wheel need not have any specific deformation, this is a bizarre idea. 
That this needs to be said is just so absurd.
"If you pick up a starving dog and make him prosperous he will not bite you. This is the principal difference between a dog and man."
― Mark Twain 🔭

Re: Direct Down Wind Faster Than The Wind
Reply #2188
  With that said, sure, it would be fun to see it chase down some balloons.
I expect the balloon test will be done.  But I can give you a 100% guarantee that it won't satisfy the idiot.  

The balloons will either be heavier than air and will therefore hit the ground at least occasionally, or they'll be lighter than air and they'll simply fly away.  On top of that, wind isn't perfectly 100% laminar with constant speed and direction.  And then you have the filming.  Even if all of the above were 100% perfect, we'd hear about how the angles were all wrong for the video.  I'm sure there are 100 more excuses I won't bother to try and think of, but surely no one here thinks a balloon test (or any other test) would ever change the idiot's mind.

Re: Direct Down Wind Faster Than The Wind
Reply #2189
What, exactly do you mean by "relativity of motion"?
I suppose you mean Galilean relativity, which refers only to uniform linear motion.

Either that or special relativity, which also refers to linear motion.  What both say is the following:  given a solution to the laws of physics (i.e. a possible physical process), you can act on it with a transformation that shifts the velocity of everything by some amount (fixed and simply additive for Galilean transforms), and the result is another solution (i.e. another possible physical process).

I don't think we need to involve SR and Lorentz transforms here as there are no relativistic velocities involved.

Now, consider a very long treadmill moving under still air, with a cart slowly advancing up the belt at speed v.  The belt moves at speed w.  Act with the Galilean transform that brings the top surface of the belt to rest.  The new situation is a cart moving at speed w + v, that much is indisputable (it's just the definition of the transform).  The top surface of the belt is at rest in the new frame, while the air is moving over it at speed w.  Therefore this is, at least by some reasonable definitions, an instance of dead dwfttw. 

It would help if you could clarify precisely where you think the above is incorrect.

Your assumption that the belt is in uniform linear motion is incorrect.

Just suppose, for a second, that the cart is driven not by the long stretch of belt, but only by the part of the belt that is going around the rollers. For the sake of argument say that the belt is moving at 4.5 m/s and the rollers have a circumference of 0.27 m so that they are rotating at 16.67 rev/sec or 1000 rpm.

The angular velocity of the rollers and the belt around the rollers is about 105 rad/sec. That is not uniform linear motion at all! We accept the surface of the earth as a nearly inertial frame even though it has an angular velocity of 7.2921159 × 10−5 rad/sec but surely you would never accept 105 rad/sec as being an inertial frame and you would never claim a Galilean transform of such motion.

Now consider that the cart's wheels also have a circumference of 0.27 m and when on that same belt, they rotate at 1000 rpm. Of course, they have the same angular velocity of 105 rad/sec and so does the section of belt that is in contact with them!

As you have noted yourself, point contact will not spin the wheels, and the belt must deform into a small arc around the bottom of those wheels. The section of belt that is passing through that arc is not in uniform linear motion, it is moving in circular motion with a angular velocity of 105 rad/sec! Let that fact sink in. Looking at the long flat expanse of belt is what is confusing you! The only part of the belt that matters to the cart is the small arcs at the bottom of the wheels, nothing else. Once you realize that you understand that the GT is wrong. In fact, you cannot claim a GT of the cart on the belt to a cart on the road.


Quote
Do you think the experiment with the balloons should be done or not?

The original Blackbird run had streamers attached that showed the relative wind direction, and it certainly looked to me that they reversed.  Furthermore GPS data showed the speed and direction and it clearly exceeded windspeed.  With that said, sure, it would be fun to see it chase down some balloons.

Yes, the streamers did reverse, at least two times in the video that I watched. The first time was at the very start of the video, before the cart ever started to move! That is the wind gusting and changing direction, that's all.
The second time was the same thing because the reversal happened so quickly that it would indicate a very fast acceleration. However, there is nothing in the video to indicate the cart itself suddenly accelerated! In fact, the cart just keeps lumbering along at the same apparent speed while the streamers reverse quickly. That is the wind!

Yes, we do need the balloons, thanks.

Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2190
............
To spin a wheel, the belt MUST deform into an arc at the bottom of the wheel, regardless of whether there is any wheel deformation or not, as I said earlier.

To roll on a surface, the wheel MUST deform where it meets the surface, regardless of whether or not there is any surface deformation.
Heinz, this is the same misconception you have been peddling for a long time and I'm pretty sure where you were introduced to it.

You considered the case where you have a rotating shaft with a pulley or wheel, and you want to transmit power to it via a belt.  The wheel is fixed in place and the moving belt has to be brought into contact with it, with some pressure, to create enough friction against the wheel to rotate it, especially with any significant torque.  In this case even the slightest pressure against the wheel will deform the belt (locally curve it) and may have to be significant in order to transmit force / power.  So to transmit any torque to the wheel, make the wheel turn, the belt has to deform.

Then you have been claiming that this is equivalent to a wheel rolling on a surface,

Absolutely not! I am saying this is very different from a wheel rolling on a surface.


and that a treadmill belt has to act the same as what I described above.


A treadmill belt that is driving a wheel is exactly what you have described above. It is not a wheel rolling on a surface.

This is nonsense; a treadmill belt is backed up by a smooth, flat surface and does not have to deform at all against a wheel to transmit torque to it.  The flat backing provides the force, not the belt tension wrapping around a wheel as with some farm implement.

Now you are the one talking nonsense. The treadmill belt does have a smooth flat surface under it; it has to in order to support the weight of the many fatasses that are running on the belt! But the belt is tensioned so that it does not always rub against that flat surface, or else a lot of the motor's energy is wasted in heat from continuous friction and the belt would soon wear out.

To roll on a firm surface, a wheel need not have any specific deformation, this is a bizarre idea.  A wheel can have lots of deformation, creating plenty of rolling resistance and also energy loss due to the hysteresis involved in rubber flexing.  Or it can be nearly infinitely rigid against a similar surface, with the least rolling resistance and energy loss.

A wheel must deform in order to roll on a flat surface. If the wheel does not deform, it will simply spin in place. Rolling involves advancing. If you march in place, you are just putting your feet down in the same spot over and over. In order to walk, you need to put one foot down in advance of the other. Likewise, in order to roll a wheel must continually place down contact points in advance of the contact point it is making at any instant in time. How can an infinitely rigid wheel possibly do that? As it turns, it will just put down a contact point in the same exact place, over and over. It is bizarre to think that an infinitely rigid wheel can roll on a flat surface! Rolling involves deformation at the contact patch, without which, no rolling can happen, only spinning in place!

Balloons anyone?

Yes, please! Lots of big bunches of balloons, the more the better. I love balloons and I will love them even more after the 19th. No need for helium-filled as they will simply lift off and out of the picture. Ordinary air-filled will do just fine for this purpose. Thanks in advance!
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2191

A wheel must deform in order to roll on a flat surface. If the wheel does not deform, it will simply spin in place. Rolling involves advancing. If you march in place, you are just putting your feet down in the same spot over and over. In order to walk, you need to put one foot down in advance of the other. Likewise, in order to roll a wheel must continually place down contact points in advance of the contact point it is making at any instant in time. How can an infinitely rigid wheel possibly do that? As it turns, it will just put down a contact point in the same exact place, over and over. It is bizarre to think that an infinitely rigid wheel can roll on a flat surface! Rolling involves deformation at the contact patch, without which, no rolling can happen, only spinning in place!



This whole business about deformation at the contact point is of course pure bullshit.  Of course it's true that a point contact of any real-world material cannot carry any force, either normal or tangential, since it would imply infinite stress or pressure at that point.  But this is just the classic bullshit lie/misdirection.  It doesn't matter whether the wheel, the surface, or both deform.  And if you really care which it is, just make the road out of the same material as the treadmill belt.


What Spork said.

Re: Direct Down Wind Faster Than The Wind
Reply #2192
For those in the audience who definitely know a lot less about physics than Heinz...
Good luck finding such a person.  I've certainly never met one.


Definitely what Spork said.

Re: Direct Down Wind Faster Than The Wind
Reply #2193
>>  The only part of the belt that matters to the cart is the small arcs at the bottom of the wheels, nothing else. 

This is my favorite quote in a long time!  After years of stupidity about how the belt didn't count since it is rotating about rollers in front of and behind the cart, now we learn that only the belt in contact with the car matters!



Re: Direct Down Wind Faster Than The Wind
Reply #2194
>> The only part of the belt that matters to the cart is the small arcs at the bottom of the wheels, nothing else.

This is my favorite quote in a long time!  After years of stupidity about how the belt didn't count since it is rotating about rollers in front of and behind the cart, now we learn that only the belt in contact with the car matters!




Did you know that, on average, our planet  receives about 84 Terrawatts of Power from the sun every 24 hours?

But the only part of that which matters, is the amount that falls on YOU! (about 164 Watts per square meter)

Amazing, eh spork?

If the belt was 5 million miles long, the only part of the belt that matters to the cart is those little arcs at the bottom of the wheels, and those arcs are not in uniform linear motion.

Bring on the Balloons!!

Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2195
A motor that's making the belt go sideways. Not up and down.

The cart.
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2196
A motor that's making the belt go sideways. Not up and down.

The cart.
Nice to see your usual level of coherence in this post.

Re: Direct Down Wind Faster Than The Wind
Reply #2197
A motor that's making the belt go sideways. Not up and down.

The cart.
Nice to see your usual level of coherence in this post.

Not clear? It is the cart that moves up and down, not the belt.

It does so because of the reaction force from the belt, when the belt delivers power to the wheels, which I explained earlier.

There is not a similar reaction force from rolling on the ground. The ground does not deliver any power to the wheels in any reference frame despite what the crackpots say.
Where are the damn balloons?

Re: Direct Down Wind Faster Than The Wind
Reply #2198
A motor that's making the belt go sideways. Not up and down.

The cart.
Nice to see your usual level of coherence in this post.

Not clear? It is the cart that moves up and down, not the belt.

It does so because of the reaction force from the belt, when the belt delivers power to the wheels, which I explained earlier.

There is not a similar reaction force from rolling on the ground. The ground does not deliver any power to the wheels in any reference frame despite what the crackpots say.
Wow. I think I finally understand part of your issues. You're amazingly bad at following a discussion. That kind of memory issue can really hinder learning. Anyway, to remind you, even though it's still on the same page, here's the context of my comment that the motor makes the belt go sideways rather than up and down...
Well I did say "apparently." But you do keep comparing the wheel resting on the treadmill to a pulley. For example, here:
In fact, any wheel deformation will make it much more difficult for the belt to spin the wheel.


Why?

Try spinning a brick with a belt and see for yourself.

Engineers go to great lengths to see that pulleys are as round as possible and usually made of rigid metal.

Pulley deformation is unwanted. Can you even guess why?
And you also have said...
Initially, the cart is held down on the belt, to get the wheels and propeller spinning, and the act of holding the cart down overcomes the reaction force. But, once the cart is released, the reaction force will push the wheels away from the belt, causing a loss of traction.
 With reduced traction, propeller thrust briefly exceeds wheel brake force and the cart can advance on the belt. But, whatever goes up must come back down, and the wheels will once again make contact, briefly, with the belt and the cart regains some or all of the energy used in the brief advance up the belt. This results in a cyclic action of the cart periodically advancing during reduction in wheel drag and periodically regaining traction and recovering energy.
That certainly sounds like a perpetual-motion trampoline. Why wouldn't it eventually stop losing traction?

And as far as the part about it functioning as a moving surface, you sure don't seem eager to analyze it as such.

How is it perpetual motion when it is all driven by a motor on the treadmill?

A motor that's making the belt go sideways. Not up and down.
As you can see, the question was why the cart doesn't eventually stop losing traction. Telling me that it's the cart moving up and down and not the belt doesn't explain why it doesn't eventually stop doing so. In reality of course, it would stop doing so almost immediately, if there even was any noticeable up/down movement, which there very likely is none.

Re: Direct Down Wind Faster Than The Wind
Reply #2199

There is not a similar reaction force from rolling on the ground. The ground does not deliver any power to the wheels in any reference frame despite what the crackpots say.

Why? Because Heinz can't understand it.