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Old 12th November 2008, 07:23 AM   #161
ThinAirDesigns
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Originally Posted by humber View Post
Yes, there appears to be little acceptance of qualitative descriptions along the lines of opposing forces. If only Einstein had not used the word "Relativity".
Yeah, "if only". LOL

In the context of this discussion Galileo and Newton beat Einstein to the punch by a large margin, but why quibble with details eh?

"13", I'm working on a response to your excellent "twin wind tunnel" question. Be with you in a bit.

Carry on.

JB
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Old 12th November 2008, 07:38 AM   #162
spork
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Quote:
humber says:
Your videos are evidence that something is happening. If I were to build one, I would fully expect to get the same result. What is being argued, is why that happens, and how it relates to support for a machine of this type that can actually travel faster than the wind.
You say you'd expect to get the same results, but you describe different results than we consistently get. This cart in a steady wind achieves a steady state speed faster than the wind. It will climb a hill steady state or it will push against a stop (at or above wind speed) steady state.

Quote:
So, do you have links for a machine that does that in a controlled constant- wind environment?
Yes. I don't think I'm permitted to post links yet, but I've posted 6 videos we've made over the past several days. Look for spork33 on youtube and you'll see them all. Most of our tests are performed on the treadmill because this gives us exactly the controlled steady-state conditions you ask for. The treadmill represents a moving road immersed in a non-moving airmass. This of course is identical to a moving airmass over a non-moving road. The principle of equivalency of inertial frames tells us there is no way for any experment to distinguis between these two cases.


Quote:
My_wan says:
Well, let's start at 0 craft speed. Propellers not turning and the wind blowing the craft itself is the only thing to move it. Once the wheels do turn then the prop turns at the same rate. We know the wheels have to be the power right now because if the wind in the prop was the power turning the wheels it would run the craft backward.
In our video #3 you can see the cart is started from a stand-still by a fairly abrupt gust. In this particular shot we did not have the rubber bands on the front wheels to act as treads. As such the wheels were forced to turn against the direction of motion of the cart for the first 3 seconds or so. This is NOT the norm. In that very same video you can see a start from a stand-still in which the prop turns in the normal direction from the very start. The reason for this is that, while the wind would *tend* to rotate the prop in the opposite direction, it also *tends* to push the prop (and therefore the cart) forward. The gearing and prop pitch is such that the latter tendency will always win out as long as the wheels don't slip.

Quote:
Anyway.. there is a clear direction that the forces propagate through the craft and I'm not just picking the one that seems to make sense
That is correct, and in normal operation this direction is always the same - whether operating on the open road or on a treadmill. The two cases are dynamically identical.

Quote:
humber
As far as I can see, the videos show a completely understandable and predictable trifle.
I think you'll see there is plenty of footage in our videos that don't even remotely support your oscillation assertion.

Quote:
OK, it seems that you are proposing a rectifying mechanism. That would work, but not without storage. That is, energy is accepted one way, stored, 'turned around' and added to the motive force. Spronk's design has this built in, but he refuses to see it.
What I refuse to ACCEPT is a baseless theory of yours that involves the non-neccessary and non-observed oscillation that you seem to require to beat the wind. Our craft can and does exceed the wind speed steady state.

Quote:
The propeller's precession, forces the rear wheels to engage with the road; the front will tend to lift, which probably accounts for its dragster-like design.
I don't think you know what precession means. It clearly has no bearing on any problem in which the cart's orientation is fixed. Perhaps you can elaborate on this.

Quote:
What this means is that when the vehicle is being driven by the wind, a large amount of energy is absorbed. On the other hand, when the wind drops, it can coast on the stored energy while releasing less to the environment than it previously stored. It accumulates and stores as it goes along.
The oscillation theory is complete bunk. That is not what's observed, and that's not what my analysis shows. This is not an oscillating system.

Quote:
If the propeller were also to be used to charge a battery and then drive a motor, would that qualify as a contender ?
NO! Steady-state operation is a requirement.

Quote:
fsol
So, we can see your calculations where?
This vector analysis along with some verbal description can fully describe how the cart works and why it's possible to exceed the wind speed steady state. Look it over and let me know when you want to discuss what it means and how it applies to this cart.

Quote:
.13. said:
Set up two wind tunnels. One has a solid floor and airflow the other has a treadmill with no airflow. Put a cart in each. Turn on the ariflow and the treadmill. Hold the carts above ground and make sure both of their wheels has zero angular velocity. Drop them on the ground. They will travel to opposite directions. Right?
If we drop each onto the surface, with no speed relative to that surface, and with no initial wheel rotation, they will behave identically with respect to the surface on which they're dropped. Galileo, Newton, and Einstein all tell us this has to be so.

Quote:
humber said:
And the video of wind-powered craft operating in a controlled constant-wind environment ?
Youtube. Look at the videos under spork33. You'll find 6 (or more by the time you may happen to check it out). We continue to post videos to responsd to specific questions. If you have a question that can be resolved by an experiment we can conduct, we will try and do so, and post a video showing the result.

Quote:
technoextreme said:
I know why. He thinks propellers work in only one direction.
I'm more familiar with the workings of propellers than you'll ever know.


Quote:
The only reason why the cart doesn't go backwards is because the forces equalize and the cart stops accelerating.
The reason the cart doesn't go backwards is because it's exploiting the energy available at the road/wind interface which makes it go forwards - faster than the wind.

Quote:
I'm not disputing the cart doesn't move but his mystical magical description ignores the fact that with the headwind the propeller starts acting like a generator in the wrong direction thus counteracting the force of the wheels.
Perhaps you should study the attached vector analysis and follow along as I describe how it pertains to the situation at hand. While it may seem mystical to you, I assure you it's just plain old physics and aero to anyone that understands the analysis.
Attached Images
File Type: jpg Clipboard01.jpg (18.6 KB, 10 views)
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Old 12th November 2008, 07:42 AM   #163
spork
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Originally Posted by ThinAirDesigns View Post
"13", I'm working on a response to your excellent "twin wind tunnel" question. Be with you in a bit.
JB, I address that question in the above tome. Unfortunately the answer could easily be missed amidst the shear quantity of verbiage. Unfortunately when I sleep the world continues to ask questions. That leads to LONG responses.

Perhaps you can add to my response to the wind-tunnel question.

Last edited by spork; 12th November 2008 at 07:47 AM.
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Old 12th November 2008, 07:48 AM   #164
ThinAirDesigns
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Originally Posted by .13. View Post
Set up two wind tunnels. One has a solid floor and airflow the other has a treadmill with no airflow.
Hi 13. I like where you're going here, but to make sure we're on the same page I may have to ask a couple questions and add a few details before we can move forward. Hope you don't mind.

Tunnel "A" will be the one with a blower that moves the air.
Tunnel "B" will be the one with the motor moving the floor.

For ease of discussion, lets say both 'tunnels' are aligned in an east/west direction.

(I know there are two videos under discussion and while the dynamics of both carts are identical, the design is a bit different. These design differences make this discussion difficult so I'm going to arbitrarily pick one design to discuss -- and I pick the small version running on the treadmill. The cart I have chosen has two front wheels and a single rear and the prop is in the rear as the cart goes 'downwind'. Now we know the front of the cart from the rear and its direction of travel.)

To make is so the carts can face and 'travel' the same direction in both tests we setup our 'tunnels' in the following manner:

Tunnel "A" has the wind blowing from west to east.
Tunnel "B" has the floor moving from east to west.
The carts face east.

Quote:
Put a cart in each. Turn on the airflow and the treadmill.
We'll do just that, and again for clarity let's set both controls to 10mph.

And one more thing before we proceed -- for sake of discussion I'm going to define the performance of our carts such that they have the performance to travel just 1mph faster than the wind that is propelling them.

Quote:
Hold the carts above ground and make sure both of their wheels has zero angular velocity.
I'm with you ... the wheels and propellers are perfectly still in relation to the cart chassis. Of course this means that on cart "A" you have to lock the prop/wheels from free-spinning as they sit in the airflow but that's easy. Cart "B" has no such need as there is no air rushing by to spin the prop.

(Note #1: Please notice the difference in the above 'start environment between "A" and "B" ... I'll be referring to it later)

Quote:
Drop them on the ground. They will travel to opposite directions. Right?
13, before I get to answering your question, would you mind confirming for me that my added details are OK with you and that I haven't twisted your scenario beyond recognition.

Thanks

JB
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Old 12th November 2008, 07:48 AM   #165
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How to make the machine go further and faster "against the wind"?

Make the prop heavier.
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Old 12th November 2008, 07:52 AM   #166
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Originally Posted by humber View Post
OK, it seems that you are proposing a rectifying mechanism. That would work, but not without storage. That is, energy is accepted one way, stored, 'turned around' and added to the motive force. Spronk's design has this built in, but he refuses to see it.
In fact the only energy storage capacity of the device in sporks video is momentum. That is p=mv where p is the momentum and mv is mass times velocity. Given the extremely low mass of the device in sporks video this momentum would run that prop at any speed for more than several seconds even without expending it pushing the craft up that incline. Much less maintain full prop speed.

So storing angular momentum in the spinning parts does occur by a very small amount. Let's assume it's enough to actually drive the craft off the treadmill as shown. This would mean that when he let loose of the craft it would take off very fast and slow down as the momentum was spent overcoming the treadmill going the other way. Now watch the video again.
http://www.youtube.com/watch?v=1BRvYZd81AQ&fmt=18
What you see is the craft taking off very slowly then gaining speed. This cannot by any stretch of the imagination be attributed to stored momentum. It would be like having your car gain speed when it lost power.
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Old 12th November 2008, 07:57 AM   #167
ThinAirDesigns
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Originally Posted by mhaze View Post
How to make the machine go further and faster "against the wind"?

Make the prop heavier.
Someone doesn't understand the term "steady state".

And just to put my above comment in context, here is my claim:

"We have built and can demonstrate upon demand a vehicle which can travel directly downwind, faster than the wind, powered only by the wind, steady state."

A heavier prop has no impact (other the added friction associated with the bearings, wheels, etc) on the results in a steady state scenario.

JB

PS: I don't think I've mentioned that I have been sporks partner in building mulitiple version of DDWFTTW devices seen on Youtube.
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Old 12th November 2008, 08:02 AM   #168
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Originally Posted by my_wan View Post
The thing missing here is the fact that as the speed of the craft increases so does the speed of the propeller.
Yes, and so does the speed of the air that the propeller pushes back. But not by the same absolute difference as the increase of the speed of the craft.

Originally Posted by my_wan View Post
Therefore the propeller will always push the air faster than the air is already moving by the same difference in speed as it was at lower speeds.
No, I'm afraid that's not the case.

As I said in my analysis, the wheels are connected to the propeller so that when the forward speed of the device (wrt ground) is vdev, the propeller tries to move the air forward (wrt ground) at speed vprop. vprop / vdev is a constant given by the transmission and the angle of the propeller blades, and I call it f, the leverage factor.

(This is from the ground's reference frame. If you wanted to look at it from the device's reference frame, which you seem to prefer, the ratio of the speed at which the propeller tries to move the air backward (wrt device) and the speed at which the ground moves backward (wrt device) is f1. The following relationship applies: f = 1 - f1. At this point, you should stop, do the math and check for yourself that this relationship is correct.)

What you need to realize is that in order for the device to move forward, f must be > 0 (and to move at higher than wind speed, it also must be < 1). This means that f1 must be < 1 (and > 0). And this means that when the forward speed of the device (wrt ground) increases by x, the backward speed at which the propeller pushes air (wrt device) also increases, but by less than x. (Verify this. Be careful with signs and reference frames; I have not used them arbitrarily, I made very sure they are right.)

This means that the difference between backward air speed (wrt device) and the speed at which the propeller pushes air backward (wrt device) decreases as the device accelerates. When the device reaches forward speed (wrt ground) vwind / f, the difference will be zero and the device will no longer accelerate. (Use math to verify this.)

If in doubt, ask Spork or JB. They seem to understand the theory behind their device and should be able to confirm this to you.

Originally Posted by my_wan View Post
If the propeller had the same RPM at all speeds then you would be right, but it doesn't.
The propeller never has the same RPM at all speeds (unless f = 1, when the propeller always has zero RPM). This has nothing to do with whether I'm right or not. See above.

Originally Posted by my_wan View Post
The wheels are geared directly to the propeller so that as the craft gains speed so does the propeller.
Yes, but not by the same amount (to be more accurate, the angular velocity of the propeller is irrelevant here; what's important is the speed at which the propeller pushes the air backward).

Originally Posted by my_wan View Post
This gearing is such that the difference in propeller speed always exceeds the wind speed relative to the propeller by the same amount at all speeds.
Strictly taken, this doesn't make sense. If instead of "difference in propeller speed" you wrote "speed at which the propeller pushes the air backward wrt device", then it would make sense, but the answer is no.

Originally Posted by my_wan View Post
This difference is the same amount as the air speed relative to the ground.
I'm afraid not. This would only be the case if f was 0, but in that case, the device would not work.

Originally Posted by my_wan View Post
There are some practical engineering issues that makes this description less than mathematically perfect yet it remains qualitatively accurate. Hopefully you can see how the constant speed difference (power source) I kept talking about applies to the propeller vs wind speed relative to the propeller now.
Sorry, that's not the case.

Originally Posted by my_wan View Post
Please try to remain as clear as you where in the post quoted above.
I tried.
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Old 12th November 2008, 08:03 AM   #169
spork
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Originally Posted by mhaze
How to make the machine go further and faster "against the wind"?
Simply use a lower prop pitch and turn the cart into the wind.


Originally Posted by my_wan View Post
Given the extremely low mass of the device in sporks video this momentum would run that prop at any speed for more than several seconds even without expending it pushing the craft up that incline. Much less maintain full prop speed.
We specifically address this question in video #5. When we lift the cart off the treadmill the prop coasts to a stop in under 7 seconds. In video #6 we manage to balance the cart and treadmill (with positive incline) well enough to keep the cart in operation unassisted for 1:48 before it falls off the treadmill. Clearly the cart didn't store enough energy to make this possible.
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Old 12th November 2008, 09:17 AM   #170
humber
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Originally Posted by my_wan View Post
In fact the only energy storage capacity of the device in sporks video is momentum. That is p=mv where p is the momentum and mv is mass times velocity. Given the extremely low mass of the device in sporks video this momentum would run that prop at any speed for more than several seconds even without expending it pushing the craft up that incline. Much less maintain full prop speed.

So storing angular momentum in the spinning parts does occur by a very small amount. Let's assume it's enough to actually drive the craft off the treadmill as shown. This would mean that when he let loose of the craft it would take off very fast and slow down as the momentum was spent overcoming the treadmill going the other way. Now watch the video again.
http://www.youtube.com/watch?v=1BRvYZd81AQ&fmt=18
What you see is the craft taking off very slowly then gaining speed. This cannot by any stretch of the imagination be attributed to stored momentum. It would be like having your car gain speed when it lost power.
Perhaps you have not read my posts, but this is largely what I have been saying, though we are not fully in agreement.

1.Yes, he shows that.
2. It's not so small, but that is not that important.
3. If that assumption is made, then there would be even less to show.

When the device is first placed on treadmill and held, (spinning) the opposing forces of drag, and that from the belt, are almost in equilibrium. So, when released it could go either way, but it goes forward. It won't take off fast, because as you say, the momentum is relatively small. In principle, it could be spent, and the device reverse direction, but in practice, simple natural mechanisms serve to maintain that momentum.

You accept the the momentum can drive it forward, so what in general, stops it from doing that? The force from the belt.
This is the crux of the matter, the drive and drag are not separate forces, but opposing forces derived from the same source, but split in direction.
It could be either; increase in one, reduction of the other.

However, the presence of the momentum, will probably, (though by no means certainly) drive the device forward. It won't "run out" because it is constantly replenished.
There are many opportunities for simple and natural phenomenon to achieve this, apart from the necessary but convenient finger.

I think you will agree that the belt "should" carry the device backwards. But what if the friction between the wheels were to be momentarily reduced?
Now the drive is gone, but the propeller is spinning, so forward it goes. When friction returns, the lost momentum can be regained. It need not necessarily be a complete loss of friction, so some mechanism, such as non-linear or slip-stick friction, could do the same. It happens over short time scales, perhaps at the frequency of the fan or treadmill motor.
It is an example of natural forced feedback with a storage element.
A fully detailed explanation would cover perturbation theory etc.

As far as the incline goes, it makes no real difference. In principle, if the forces were to be completely and always in balance, then the device would stay in position regardless of how fast the drive belt were to be going. Changing the angle simply changes the horizontal component of the forces.

So, properly designed, I would think such device could show much more assured progress than you see in the videos.
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Old 12th November 2008, 09:19 AM   #171
humber
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Originally Posted by ThinAirDesigns View Post
Yeah, "if only". LOL

In the context of this discussion Galileo and Newton beat Einstein to the punch by a large margin, but why quibble with details eh?

"13", I'm working on a response to your excellent "twin wind tunnel" question. Be with you in a bit.

Carry on.

JB
Yes, if only people read Einstein's papers, those that he won the Nobel prize for, perhaps the would learn something about momentum.
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Old 12th November 2008, 09:39 AM   #172
.13.
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Originally Posted by ThinAirDesigns View Post
13, before I get to answering your question, would you mind confirming for me that my added details are OK with you and that I haven't twisted your scenario beyond recognition.

Thanks

JB
Looks good.


Originally Posted by spork View Post
JB, I address that question in the above tome. Unfortunately the answer could easily be missed amidst the shear quantity of verbiage. Unfortunately when I sleep the world continues to ask questions. That leads to LONG responses.

Perhaps you can add to my response to the wind-tunnel question.
I noticed. I'll let JB answer it with more detail.
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Old 12th November 2008, 10:01 AM   #173
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So if the cart is placed on an incline, in still air, it will go uphill spontaneously?

Scalability? How big of a prop is needed to actually make man-sized one?
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Old 12th November 2008, 10:07 AM   #174
.13.
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Originally Posted by my_wan View Post
The emphasized statement was:
"if the wind in the prop was the power turning the wheels it would run the craft backward".
Now look at the diagram I drew:
http://www.internationalskeptics.com...aaeb9be526.gifDirection of travel is to the left <----.

Notice that when the wheels rotate as shown the prop ejects air to the right while the wind travels to the left. Now if this wind is what turned the propeller the ejected air would necessarily be in the same direction as the air turning it, but it's not. If the air output is reversed from that shown the wheels must also turn in the opposite direction, because they are directly connected, making the craft go right instead of left as shown. Since the craft does go left the prop must be driven by the wheels and not visa versa. So there's you "why" on the emphasized statement.
You say: "Now if this wind is what turned the propeller the ejected air would necessarily be in the same direction as the air turning it, but it's not."

I agree that the air is not ejected backwards. But: That doesn't mean the wind isn't turning the propeller. The propeller slows down the wind flowing through it and that gives the cart energy to move forward. Right?

If you were right and the wind would drive the cart to opposite direction: Wouldn't the cart initially accelerate backwards instead of forward?
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Old 12th November 2008, 10:25 AM   #175
humber
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Originally Posted by spork View Post
You say you'd expect to get the same results, but you describe different results than we consistently get. This cart in a steady wind achieves a steady state speed faster than the wind. It will climb a hill steady state or it will push against a stop (at or above wind speed) steady state.
Referring to the item on the belt, I have never expressed otherwise. The wind experiment could be anything. I have already covered that. Against a stop is even easier. However, you do claim that the treadmill experiments support the wind versions. You do disagree with my version of how it operates. Also the claim that these demonstrations violate any of the known laws of physics. I heard that.

Quote:
Yes. I don't think I'm permitted to post links yet, but I've posted 6 videos we've made over the past several days. Look for spork33 on youtube and you'll see them all. Most of our tests are performed on the treadmill because this gives us exactly the controlled steady-state conditions you ask for. The treadmill represents a moving road immersed in a non-moving airmass. This of course is identical to a moving airmass over a non-moving road. The principle of equivalency of inertial frames tells us there is no way for any experment to distinguis between these two cases.
OK, but please stop making such claims for wind performance until demonstrated.

Quote:
In our video #3 you can see the cart is started from a stand-still by a fairly abrupt gust. In this particular shot we did not have the rubber bands on the front wheels to act as treads. As such the wheels were forced to turn against the direction of motion of the cart for the first 3 seconds or so. This is NOT the norm. In that very same video you can see a start from a stand-still in which the prop turns in the normal direction from the very start. The reason for this is that, while the wind would *tend* to rotate the prop in the opposite direction, it also *tends* to push the prop (and therefore the cart) forward. The gearing and prop pitch is such that the latter tendency will always win out as long as the wheels don't slip.
Quote:
That is correct, and in normal operation this direction is always the same - whether operating on the open road or on a treadmill. The two cases are dynamically identical.
I think you'll see there is plenty of footage in our videos that don't even remotely support your oscillation assertion.
I think you are assuming that I connect the treadmill and real-world wind performance. They show superficial similarities, but I have already mentioned that I don't seriously connect the two. My "oscillation assertion" applies to the the video posted by the OP. The big trolley with the wooden propeller. I didf suggest that as a putative mechanism for how the trolley moves up the treadmill. They are not strongly related ,though

Quote:
What I refuse to ACCEPT is a baseless theory of yours that involves the non-neccessary and non-observed oscillation that you seem to require to beat the wind. Our craft can and does exceed the wind speed steady state.
I have not seen any evidence that it beats the wind. Yours or any other. Once again, most this applies to the other video. Your wind demonstrations are in another category again.

Quote:
I don't think you know what precession means. It clearly has no bearing on any problem in which the cart's orientation is fixed. Perhaps you can elaborate on this.
In the only video showing any real claim to recorded performance is the one that I just mentioned. The precession of that propeller, will indeed do as I claim. However, it could be something that concerns the other model in terms of stability. I used it to demonstrate that the cart in that video is nothing more than a flywheel on wheels, which it is.

Quote:
The oscillation theory is complete bunk. That is not what's observed, and that's not what my analysis shows. This is not an oscillating system.
Must be some misunderstanding.

Quote:
NO! Steady-state operation is a requirement.
Irony

Quote:
This vector analysis along with some verbal description can fully describe how the cart works and why it's possible to exceed the wind speed steady state. Look it over and let me know when you want to discuss what it means and how it applies to this cart.
Sorry, but I really don't know what you are on about here. The device in video #3, in the carpark? Well, that's another matter. Looks to me like it is a response to the gust that initiates its launch. Could be anything.
I am surprised that you think there is anything to claim.

Quote:
Perhaps you should study the attached vector analysis and follow along as I describe how it pertains to the situation at hand. While it may seem mystical to you, I assure you it's just plain old physics and aero to anyone that understands the analysis.
Are we going sailing ? The drive belt demonstrations are said to support your ideas.
I agree, it's just plain old aero. Air is quite viscous you know. The performance of objects of the size and mass shown in #3, are not subject to such simple analysis.

Last edited by humber; 12th November 2008 at 10:55 AM.
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Old 12th November 2008, 10:45 AM   #176
mhaze
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Originally Posted by .13. View Post
You say: "Now if this wind is what turned the propeller the ejected air would necessarily be in the same direction as the air turning it, but it's not."

I agree that the air is not ejected backwards. But: That doesn't mean the wind isn't turning the propeller. The propeller slows down the wind flowing through it and that gives the cart energy to move forward. Right?

If you were right and the wind would drive the cart to opposite direction: Wouldn't the cart initially accelerate backwards instead of forward?
If the machine does not operate by way of a transient stored momentum (this being partly in the machine, and partly in the local airstream) then it should be possible to put on it, RC controls and get it to remain stationary on the moving belt for an arbitrary length of time.

Glue a small diameter tube to the machine, and place it on the treadmill with a piano wire parallel to the track, said wire sliding through the tube. Use one RC servo to vary friction against the wire with a felt pad - this is to keep the machine from sliding off the forward end of the treadmill.
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Old 12th November 2008, 11:00 AM   #177
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Too much like evidence.
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Old 12th November 2008, 11:08 AM   #178
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Originally Posted by Thabiguy View Post
Yes, and so does the speed of the air that the propeller pushes back. But not by the same absolute difference as the increase of the speed of the craft.
Which is exactly why the wind speed difference wrt craft remains a constant at all speeds. It may not be exactly the "same absolute difference" but close enough and it can be designed so that it does making it even more efficient.

Originally Posted by Thabiguy View Post
No, I'm afraid that's not the case.
So just because the difference is not exact due to design issues that a difference is not maintained at all. Isn't that like admitting that a properly designed craft would work but since this one isn't perfect it can't work?

Originally Posted by Thabiguy View Post
As I said in my analysis, the wheels are connected to the propeller so that when the forward speed of the device (wrt ground) is vdev, the propeller tries to move the air forward (wrt ground) at speed vprop. vprop / vdev is a constant given by the transmission and the angle of the propeller blades, and I call it f, the leverage factor.
Quote one says: "propeller pushes back". Here you say: "the wheels are connected to the propeller so that when the forward speed of the device (wrt ground) is vdev, the propeller tries to move the air forward". The propeller cannot possibly change direction and start moving the air forward without reversing direction of the prop which also reverses direction of the wheels.

When the craft first takes off the prop is moving air in the opposite direction of the wind. If the wind was powering it it would go the same direction, not opposite. You only need to watch carefully the video below to see that. Once the craft gets faster than the ground wind speed then the prop wind is going the same direction as the wind. Therefore the wind can't reverse it because the wind is helping it go that direction, which is the same direction it was going when below wind speed and blowing against the wind.

Watch this video again and pay careful attention to the prop blade angles and the direction of wind.
http://www.youtube.com/watch?v=aJpdWHFqHm0
Below ground wind speed the prop is working against the wind. So if the prop was going to reverse its direction due to wind it would be before the craft exceeded ground wind speed, not after.
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Old 12th November 2008, 11:24 AM   #179
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The sock is scarcely evidence of anything. Not far out enough to definitely say it is the breeze, yet close enough to the obfuscating propeller. This is an extraordinarily lax way of demonstrating a supposedly extraordinary device. Smoke and mirrors.
There is sufficient momentum to cover transient wind drops.
Propeller's are simply not a case of driving one way or the other, but you already know that.
Real wind is not an homogeneous entity. It has general and local turbulence, and very locally, around objects such as trees, road surfaces and dodgy wind carts. Weeps.

Last edited by humber; 12th November 2008 at 11:25 AM.
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Old 12th November 2008, 11:40 AM   #180
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Originally Posted by mhaze View Post
If the machine does not operate by way of a transient stored momentum (this being partly in the machine, and partly in the local airstream) then it should be possible to put on it, RC controls and get it to remain stationary on the moving belt for an arbitrary length of time.

Glue a small diameter tube to the machine, and place it on the treadmill with a piano wire parallel to the track, said wire sliding through the tube. Use one RC servo to vary friction against the wire with a felt pad - this is to keep the machine from sliding off the forward end of the treadmill.

Humber:
Quote:
Too much like evidence.
Perhaps I'm confused here. Are the two of you claiming that our video, posted on youtube and titled "downwind faster than the wind #6", showing the cart running on the treadmill *untouched* by human hands for almost TWO MINUTES, doesn't cover all the points in mhaze's post?

OK, I'll asked the question directly -- If close to two minutes isn't enough time to convince you, within the 10 minute limit of YouTube, how long must we leave it run before you will drop the "stored momentum" argument?

JB
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Old 12th November 2008, 11:47 AM   #181
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Originally Posted by .13. View Post
You say: "Now if this wind is what turned the propeller the ejected air would necessarily be in the same direction as the air turning it, but it's not."

I agree that the air is not ejected backwards. But: That doesn't mean the wind isn't turning the propeller. The propeller slows down the wind flowing through it and that gives the cart energy to move forward. Right?
Yes, except that the wind is not what's turning the prop. If the prop is spinning against the wind so that it slows the wind down where does the prop get the energy to actively slow that wind down? From the wheels, not the turning prop. The wheels get the energy from forward motion of the whole craft, not from the turning prop. So yes, the wind is trying to slow down the prop, plus it's pushing the whole cart, which gives the cart forward motion. The forward motion turns the wheels. The wheels give the prop the power to turn the prop against what the wind is trying to make it turn. Therefore the wind cannot be what is turning the prop.

Once the craft exceeds ground wind speed then the wheels no longer have to force the prop against the wind because the wind relative the to prop is now working in the same direction. The continued force through the wheels now only has to add motion to the wind instead of working to slow it down.

Originally Posted by .13. View Post
If you were right and the wind would drive the cart to opposite direction: Wouldn't the cart initially accelerate backward instead of forward?
No, because the wind is pushing the whole cart, not just the prop rotation. The motion of the whole cart give the wheel torque which then provides the torque to turn the prop in the opposite rotation of what the wind alone would turn it. Once faster than the ground wind speed it no longer has to work against the wind to continue turning the prop that same direction.
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Old 12th November 2008, 11:49 AM   #182
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Please read my answer to my_wan #170. Two minutes, 2 months. Why do you at all see this as relevant?
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Old 12th November 2008, 11:58 AM   #183
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Originally Posted by humber View Post
Referring to the item on the belt, I have never expressed otherwise. The wind experiment could be anything.
The two cases are identical to the cart. If you understood the basic principle of equivalency of inertial frames you would never argue differently for a moment.

Quote:
However, you do claim that the treadmill experiments support the wind versions.
Yes - because they are identical. This is not worthy of debate at any level.

Quote:
You do disagree with my version of how it operates.
I don't think that's an accurate characterization. I think it's more accurate to say - I've described exactly how it operates. I've pointed out that your "theory" is demonstrably wrong. I designed and built the silly thing based on first principles of aerodynamics (which really didn't strain my aero background). What would possibly make you think that you had any basis to correct my math and experimental results?

Quote:
Also the claim that these demonstrations violate any of the known laws of physics. I heard that.
I have stated clearly and repeatedly that this cart does NOT violate any physical laws.

Quote:
please stop making such claims for wind performance until demonstrated.
I've demonstrated it every day for over a week. I've posted the results for all to see. Please stop making bizarre statements about physics and aerodynamics when you clearly have no background whatever in these fields.

Quote:
I think you are assuming that I connect the treadmill and real-world wind performance.
No - I don't. You've made it quite clear that you're ignorant of the fact that the two are identical.

Quote:
My "oscillation assertion" applies to the the video posted by the OP.
Your "oscillation assertion" is an idea akin to the proof that we haven't put men on the moon.

Quote:
I have not seen any evidence that it beats the wind.
Indeed you have. But your denial of basic physical laws causes you to claim otherwise.

Quote:
The precession of that propeller, will indeed do as I claim.
Precession of the propeller cannot possibly even come into play unless the attitude of the vehicle is changing. You clearly don't understand what precession means.

Quote:
Must be some misunderstanding.
Yes; your misunderstanding of the most fundamental laws of physics and of the scientific method.
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Old 12th November 2008, 12:00 PM   #184
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Originally Posted by mhaze View Post
If the machine does not operate by way of a transient stored momentum (this being partly in the machine, and partly in the local airstream) then it should be possible to put on it, RC controls and get it to remain stationary on the moving belt for an arbitrary length of time.
That is absolutely true. Perhaps we'll do that experiment, but all it will prove is that people will then claim we're powering the vehicle with the onboard battery.
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Old 12th November 2008, 12:00 PM   #185
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Originally Posted by humber View Post
Please read my answer to my_wan #170. Two minutes, 2 months. Why do you at all see this as relevant?
I'm sorry humber, I though from your "too much like evidence" comment that you agreed with mhaze's post immediately previous to yours.

mhaze's description of mounting a guide system to the treadmill demonstrated he wished to see it run longer than it has -- I'm simply asking the obvious question ... how long is enough.

My mistake as related to you, but the question still stands to mhaze.

JB

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Old 12th November 2008, 12:02 PM   #186
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my_wan, are your referring to the propeller actually rotating in the opposite direction? I see it only for a brief period.
It could be aliasing. It depends upon the RPM and the video frame rate.
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Old 12th November 2008, 12:06 PM   #187
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Originally Posted by my_wan View Post
Once the craft exceeds ground wind speed then the wheels no longer have to force the prop against the wind because the wind relative the to prop is now working in the same direction.
That is not true. I've shown this in my vector analysis. If you don't care for mathematical proof and experimental results, little can be done.


Quote:
Once faster than the ground wind speed it no longer has to work against the wind to continue turning the prop that same direction.
Please review my vector analysis. It is the foundation upon which I designed the cart.
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Old 12th November 2008, 12:07 PM   #188
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humber:
Quote:
The precession of that propeller, will indeed do as I claim.
-

I just have to get in on this one quickly.

Humber, how in the world to you come up with any reasonable expectation of precession effect when we're driving it straight up a treadmill -- remember, we're not taking this thing out on a curvy road for a spin after all.

???????

Where do you get this stuff?

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Old 12th November 2008, 12:07 PM   #189
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Originally Posted by humber View Post
Too much like evidence.
It started out as just a claim by spork. Evidence needed. Spork built a proof of concept model. mhaze post some idea of an experiment that doesn't indicate what he claims is would. In fact the friction servo is physically no different whatsover from the spoon (spork) that spork used to hold the craft in check in the video. You respond tongue in cheek: "Too much like evidence". Yet the experiments and analysis continue while you are so smug without ever even leaving your computer chair.

True, the burden is on us pro guys. I just thought the irony of the irony of the smugness was worth noting.
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Old 12th November 2008, 12:09 PM   #190
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Originally Posted by my_wan View Post
Yes, except that the wind is not what's turning the prop. If the prop is spinning against the wind so that it slows the wind down where does the prop get the energy to actively slow that wind down? From the wheels, not the turning prop. The wheels get the energy from forward motion of the whole craft, not from the turning prop. So yes, the wind is trying to slow down the prop, plus it's pushing the whole cart, which gives the cart forward motion. The forward motion turns the wheels. The wheels give the prop the power to turn the prop against what the wind is trying to make it turn. Therefore the wind cannot be what is turning the prop.

Once the craft exceeds ground wind speed then the wheels no longer have to force the prop against the wind because the wind relative the to prop is now working in the same direction. The continued force through the wheels now only has to add motion to the wind instead of working to slow it down.



No, because the wind is pushing the whole cart, not just the prop rotation. The motion of the whole cart give the wheel torque which then provides the torque to turn the prop in the opposite rotation of what the wind alone would turn it. Once faster than the ground wind speed it no longer has to work against the wind to continue turning the prop that same direction.
Now I get it. The prop is set in such a way that if I were to rotate it with my finger, in the direction where the wind would rotate it if it were allowed to spin freely, it would spin the wheels backwards. Right?

EDIT:
After reading post #187 by spork it seems you've made a mistake or I misunderstood your meaning.

Last edited by .13.; 12th November 2008 at 12:18 PM.
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Old 12th November 2008, 12:15 PM   #191
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Originally Posted by ThinAirDesigns View Post
<snip>
My mistake as related to you, but the question still stands to mhaze.
JB
OK JB, no problem, but it would be disingenuous of me to completely disown the remark. You know why I don't see it as relevant, but I still don't understand why you do.
If a cat tries to climb a slippery pole, it like in the cartoons, could scramble to stay in one place. It only has to accumulate enough force to defeat gravity. If the period between scrambles is long enough, then it will be seen to move up and down a bit. As those periods become shorter, it looks more and more like it is remaining in the same position. This is not a completely accurate analogy, but it does have some descriptive value, I think.
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Old 12th November 2008, 12:16 PM   #192
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Originally Posted by humber View Post
my_wan, are your referring to the propeller actually rotating in the opposite direction? I see it only for a brief period.
It could be aliasing. It depends upon the RPM and the video frame rate.
After the craft gains speed you can see the aliasing kick in. When he pushes it just a few inches you can easily see the actual rotation. Aliasing cannot be an issue when the entire movement is only a fraction of a rotation. Click full screen and wait till his second try to make it even easier to see.
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Old 12th November 2008, 12:17 PM   #193
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Originally Posted by .13. View Post
Now I get it. The prop is set in such a way that if I were to rotate it with my finger, in the direction where the wind would rotate it if it were allowed to spin freely, it would spin the wheels backwards. Right?
Yes, exactly.
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Old 12th November 2008, 12:25 PM   #194
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Originally Posted by humber View Post
OK JB, no problem, but it would be disingenuous of me to completely disown the remark. You know why I don't see it as relevant, but I still don't understand why you do.
If a cat tries to climb a slippery pole, it like in the cartoons, could scramble to stay in one place. It only has to accumulate enough force to defeat gravity. If the period between scrambles is long enough, then it will be seen to move up and down a bit. As those periods become shorter, it looks more and more like it is remaining in the same position. This is not a completely accurate analogy, but it does have some descriptive value, I think.
Humber, while we're conversing -- You must know of course I disagree with your version of how the device works, but I've no problem with that, it just presents a fun challange.

Let's you and I devise a test that will confirm or falsify your claims. It can't be hard to do.

I do have to concede I truly don't understand your theory -- some sort of high frequency hopping arrangement ?? What makes you think that it hops?

JB
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Old 12th November 2008, 12:29 PM   #195
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Originally Posted by ThinAirDesigns View Post
humber:
Humber, how in the world to you come up with any reasonable expectation of precession effect when we're driving it straight up a treadmill -- remember, we're not taking this thing out on a curvy road for a spin after all.
>snip>
JB
This is a mix-up, at least I think it is. I can't link here to the video, but it's in the first post, behind the agreement notice.

The precession effect is only of little consequence. If the friction between the wheels can be modulated, it provides a means of non-linearity, that can be used to "decouple" the otherwise permanent connection of the propeller to the road. Connection between the road and the wheels is critical to the hypothesis. If it is broken even only, say, 10% of the time, perhaps due to road texture, then that can be enough to make the claim invalid. Precession will force connection when driven, more than it will when coasting, a matter in favour of the builder.

This does have a passing resemblance to the way that the treadmill model uses transient energy, but I did not specifically mention in that connection.
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Old 12th November 2008, 12:37 PM   #196
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Originally Posted by ThinAirDesigns View Post
Let's you and I devise a test that will confirm or falsify your claims. It can't be hard to do.
I do have to concede I truly don't understand your theory -- some sort of high frequency hopping arrangement ?? What makes you think that it hops?
JB
This is difficult, because the problem is quite specific to the circumstances, and I don't see how it is possible to disprove anything that doesn't exist. I mean, I could only shoot myself in the foot by showing something that doesn't work. It's a natural phenomenon.
I will certainly think about it, though.
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Old 12th November 2008, 12:39 PM   #197
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The treadmill videos prove nothing. A motor coupled to a prop is going to create thrust. Nothing groundbreaking about that.
Without storing energy or doing anything more complex than coupling a wheel to a prop, this craft is supposedly traveling faster than the tailwind powering it.
Looking at your plans, this is essentially the same craft I built as kid 25 years ago. That's how I found out about entropy.
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Old 12th November 2008, 12:44 PM   #198
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Originally Posted by my_wan View Post
It started out as just a claim by spork. Evidence needed. Spork built a proof of concept model. mhaze post some idea of an experiment that doesn't indicate what he claims is would. In fact the friction servo is physically no different whatsover from the spoon (spork) that spork used to hold the craft in check in the video. You respond tongue in cheek: "Too much like evidence". Yet the experiments and analysis continue while you are so smug without ever even leaving your computer chair.

True, the burden is on us pro guys. I just thought the irony of the irony of the smugness was worth noting.
my-wan, I have said before, this is not about people. It may surprise you to learn that I do appreciate the effort that has been expended, but it baffles me a bit, because theory so profoundly contradicts the given explanation, if not the device itself. Secondly, reality does not allow compensation for trying. Trust me, I do experiments. Emoticon noted.

ETA:
I should say that I am more likely to respond to "can you explain this" than claims of overturning
centuries of scientific endeavor, based upon ???? and sarcasm.

Last edited by humber; 12th November 2008 at 12:59 PM.
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Old 12th November 2008, 12:55 PM   #199
ThinAirDesigns
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Originally Posted by JWideman View Post
The treadmill videos prove nothing. A motor coupled to a prop is going to create thrust. Nothing groundbreaking about that.
Without storing energy or doing anything more complex than coupling a wheel to a prop, this craft is supposedly traveling faster than the tailwind powering it.
Looking at your plans, this is essentially the same craft I built as kid 25 years ago. That's how I found out about entropy.
Hello again JW. Did you read my post #134?

If your interested in an exchange on the subject of inertial frames of reference, I would love to have one with you.

If not, that's cool as well.

JB

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Old 12th November 2008, 01:00 PM   #200
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Originally Posted by JWideman View Post
The treadmill videos prove nothing. A motor coupled to a prop is going to create thrust.
This has been explained numerous times. From the point of view of the vehicle, there is no difference between being on a treadmill in still air and on the ground in wind. Yes, the energy that moves the vehicle forward comes from the treadmill motor. That is irrelevant.
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