Down wind faster than the wind

[CaveDave]

Originally Posted by CaveDave
Because of limitations of my OS, machine, and connection, I don't attempt you-tube or any other video downloads

Would someone post some good still shots and also a plan-view (overhead view) diagram showing the road, vehicle, direction of travel, wind direction, and propeller axis orientation with blade angle/rotation direction all included?

Hey, I don't want you to risk a youtube download. I'll be happy to get all that documentation together for you. But that doesn't seem like enough. I could bring the cart by your house, and we'll do the experiment together. When is good for you?

You left out the why:

it takes an hour for 5 minutes of unviewable images and chopped audio.

Your response seems to indicate you believe I made an unreasonable request.

I don't believe a couple of stills from the video and a photo of a simple sketch or two (I assume one of you have a camera if you make videos) could be that burdensome to provide.

You and your friends came here to convince us of the efficacy of the device, I think it should be your burden to provide the evidence.

Cheers.

Dave

 

[spork]

If I am wrong, you will be able to tell me so. I ask you to please tell me how the following is flawed.

Will do.

this cart will only run faster than the wind, if the wind is variable.

This is incorrect. The cart will go downwind faster than the wind in a perfectly steady wind. And it will do so steady state. I've done the analysis, and we've built a cart. Neither the math nor the real world backs you up on this.

That is all that this device does. It's a wind-driven flywheel.

You're simply incorrect. The math and the real world do not back you up here.

I can point to clues and indicators shown in the video, that support this contention, but can tell me why that explanation does not work ?

The explanation doesn't work because it simply isn't correct. Whether gusts will tend to increase the speed of the cart is not at issue. What is at issue is how fast the cart will be going. And it's already going faster than the wind. This is shown by analysis and experiment.

Spork's model is similar. Its momentum keeps it running in a very similar manner. The belt is the wind. If the cart slows, momentum drives it until some small disturbance allows it to pick up more. That's it.

I love it! We'll call this "small disturbance drive". How many miles per small disturbance can we get?

Newton's law of opposite and equal reaction, means that the cart will certainly not follow the belt backwards, because of the opposing 'thrust' of the propeller.

Well, that's interesting. In that case it's a real pisser that JB and I spent so many hours before succeeding. I guess our earlier attempts weren't aware of Newton's second law - because they managed to follow the belt backwards.

The cart 'mirrors' its input. Momentum does the rest. If it slows, then energy comes from the stored momentum to maintain that speed.
I agree it appears circular in description.

"circular"? not so much. Utter nonsense based on your unfounded opinion? More like it.

if it slows, the momentum of the flywheel, a reservoir of energy, can be called upon to drive it forward again. It takes what energy it it needs; directly from the belt, or from stored momentum, so as to maintain that balance.

You're making my brain hurt.

You know what's a much more likely theory? The analysis that we've presented. The analysis that actually predicts exactly what we see both on the open road and the treadmill. There's really no need to appeal to negative energy crystal pyramid flywheel flux inverters.

 

[humber]

To add to the general hubbub, the force is drag and not thrust.
However, it is not necessary to make that distinction, but that one is the opposite of the other. That's agreed, I think.

Try a cart that has sails and skids rather than wheels. If the friction between the skids and the belt is zero, then in a vacuum, it could be moved about at will.
Add air, and the sail will create a drag force in opposition to any attempt to move it forward or backwards along the belt.
The propeller provided drag, because it opposes movement along the belt.
Call that thrust then, but be consistent with that definition.

 

[spork]

I think it should be your burden to provide the evidence.

If convincing you mattered to me, the burden would definitely be mine. I care just enough to meet you 99% of the way. We did the analysis, built two carts, tweaked them for days, tested and demonstrated them indoors and out, took many videos, posted them on youtube, and have spent countless hours trying to help explain the simple truth of how and why this little parlour trick works just fine without violating every law of physics.

If you don't care to let your computer download a youtube video, you're going to miss all the truly globe changing breakthroughs you would otherwise experience (because that's where they all are).

 

[humber]

Spork,
Note that I was referring to the original video with the windsock. You have not explained why that is not an adequate explanation.

You are claiming to have a video of a vehicle like your model that exceeds windspeed. I take it that this was conducted in a wind tunnel with verified constant speed? Please, show me this. I would be astonished.

The math does not back up the idea. It contradicts. In fact, it's based upon the assumption that zero is not zero.
If you would have me believe that the videos are 'proof' then you must also supply a plausible means of operation.

See previous post regarding drag.

It's a prediction based upon a false assumption that supports itself. Seeing is not necessarily believing.
It is not at all fair to say, "See, it works" if you are the only judge on the matter and have complete control of the experiment.

 

[spork]

Spork,
Note that I was referring to the original video with the windsock. You have not explained why that is not an adequate explanation.

It's not about coming up with an "adequate explanation". The object is to arrive at the correct explanation. Your explanation simply isn't correct. There's nothing about it that's correct. If I tell you the moon orbits the earth because the sky is blue, how will you counter that brilliant argument? Here's how - you should tell me that my "explanation" is simply B.S.

You are claiming to have a video of a vehicle like your model that exceeds windspeed. I take it that this was conducted in a wind tunnel with verified constant speed? Please, show me this. I would be astonished.

I believe the videos are linked in this thread.

The math does not back up the idea. It contradicts. In fact, it's based upon the assumption that zero is not zero.

Do you have a random word generator you use to come up with this stuff?

If you would have me believe that the videos are 'proof' then you must also supply a plausible means of operation.

The videos are what they are. Take them as you like. The fact that you don't like, or can't follow, the explanations doesn't mean they haven't been offered.

See previous post regarding drag.

No

It is not at all fair to say, "See, it works" if you are the only judge on the matter and have complete control of the experiment.

I've told you how to build one of these things. You may choose to do so. You may even succeed. You might then become a believer. But I have no hope or expectation that you'll ever understand how it works.

 

[humber]

I love it! We'll call this "small disturbance drive". How many miles per small disturbance can we get?
Well, that's interesting. In that case it's a real pisser that JB and I spent so many hours before succeeding. I guess our earlier attempts weren't aware of Newton's second law - because they managed to follow the belt backwards. "circular"? not so much. Utter nonsense based on your unfounded opinion? More like it.

No. Newton's law of opposite and equal reaction mean that thrust and drag are opposing forces, but it also means that the decision as to which is which is arbitrary. That is not necessary to any equations on the matter. A force is a force, just the sign changes.
Convention has it, that thrust is the force that comes from some motivator.

The belt drives the wheels and propeller. When the propellor's mass absorbs energy, then it appears it drag. When that same mass returns energy it is thrust. The choice of name is arbitrary, as long as the distinction is consistent. That's the flaw in your argument and calculations.


I cannot find a links to your experiments other than the treadmills. Where are they, please?
Your videos are not only presented for viewing, but you claim a means of operation, and describe a critics a "genius". Not so facile, is it?

 

[spork]

Why am I getting a completely innaccurate remedial course in dynamics from a person so hard of thinking?

That's the flaw in your argument and calculations.

My flawed arguments and calculations resulted in a very real vehicle that does exactly what those calculations predicted. And now that I offer you a paint-by-numbers approach to repeating these experiments yourself with little or no trial and error - I get the most bizarre lecture about how dynamics works. What I don't hear is "you're darn right I'm going to build one - and prove you wrong".

 

[humber]

Why am I getting a completely innaccurate remedial course in dynamics from a person so hard of thinking?
<snip>

Spork,they are subjective assertions.
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.

So, do you have links for a machine that does that in a controlled constant- wind environment?

 

[my_wan]

I feel I should clarify this somewhat. The drag certainly does lower the top speed, but even if there was no unwanted drag at all, the device still wouldn't be able to accelerate indefinitely. The propelling assembly provides forward force only up to a certain speed (v_wind / f). At this speed, the propeller is pushing back the air at the same speed as the air is already flowing back (with respect to the device), so the air will no longer exert any force on the propeller. The drag makes the actual limit lower than that, but this is the fundamental limit of the concept.

I'm glad to finally get any sort of clarification. Now take a close look at this sentence:

"At this speed, the propeller is pushing back the air at the same speed as the air is already flowing back (with respect to the device), so the air will no longer exert any force on the propeller."

The thing missing here is the fact that as the speed of the craft increases so does the speed of the propeller. 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. If the propeller had the same RPM at all speeds then you would be right, but it doesn't. The wheels are geared directly to the propeller so that as the craft gains speed so does the propeller. 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. This difference is the same amount as the air speed relative to the ground.

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. Please try to remain as clear as you where in the post quoted above.

 

[my_wan]

Because of limitations of my OS, machine, and connection, I don't attempt you-tube or any other video downloads: it takes an hour for 5 minutes of unviewable images and chopped audio.

Would someone post some good still shots and also a plan-view (overhead view) diagram showing the road, vehicle, direction of travel, wind direction, and propeller axis orientation with blade angle/rotation direction all included?

Cheers

Dave

Here is a very simple diagram of the craft.

Direction of travel is to the left <----.

 

[humber]

I'm glad to finally get any sort of clarification. Now take a close look at this sentence:

"At this speed, the propeller is pushing back the air at the same speed as the air is already flowing back (with respect to the device), so the air will no longer exert any force on the propeller."

The thing missing here is the fact that as the speed of the craft increases so does the speed of the propeller. 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. If the propeller had the same RPM at all speeds then you would be right, but it doesn't. The wheels are geared directly to the propeller so that as the craft gains speed so does the propeller. 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. This difference is the same amount as the air speed relative to the ground.

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. Please try to remain as clear as you where in the post quoted above.

My_wan, it seems that you are making the same mistake as others.
Not F1-F2 = 0, But F1+F2 =2.

The 'speed' of the wind is not the direct issue, but whether it releases to, or absorbs energy from the environment. The gearing works both ways. It allows perhaps more energy to be absorbed, say through higher efficiency, but that very mechanism reduces the potential motive force by the same amount.
At an exaggerated scale, the propeller is passing through a sea of tennis balls of varying kinetic energy. It is not the 'speed' that counts but the propellers capacity to absorb or release momentum from those tennis balls.
So it seems to me, that this is ignored, and the sign of the force, is decided on the basis that it is supports or denies a working device.

 

[my_wan]

My_wan, it seems that you are making the same mistake as others.
Not F1-F2 = 0, But F1+F2 =2.

The 'speed' of the wind is not the direct issue, but whether it releases to, or absorbs energy from the environment. The gearing works both ways. It allows perhaps more energy to be absorbed, say through higher efficiency, but that very mechanism reduces the potential motive force by the same amount.
At an exaggerated scale, the propeller is passing through a sea of tennis balls of varying kinetic energy. It is not the 'speed' that counts but the propellers capacity to absorb or release momentum from those tennis balls.
So it seems to me, that this is ignored, and the sign of the force, is decided on the basis that it is supports or denies a working device.

Good point. I'll use this sentence of yours to represent what you said: "The gearing works both ways." Yes it in fact does. It is also a fact that by changing gear ratios and other parameters you can make it work both ways in practice. So the question then is which direction does the torque actually come from in practice given the plans spork published?

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. So now all we have to do is increase prop speed at the same rate and the craft speed and the same relative condition persist. The prop therefore continues to be powered by the wheels and the prop speed only increases enough to maintain exactly the same wind differential even as the craft gains speed. Just because it exceeds ground wind speed does not mean it exceeds wind speed relative to the craft, due to the prop.

The way I got through this part in my thinking was to consider the drive shaft run into a ring with a flange. The drive shaft has a peg so it turns freely in the ring until it hits the flange. This mean the peg will be on one side if the wheels power the prop and on the other side if the prop powers the wheels. It can't be both at the same time unless you want to call it Schroedinger's craft, LMAO. 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. I even had to concede the Betz' Law issue to spork in a previous debate for this very reason.

 

[humber]

Good point. I'll use this sentence of yours to represent what you said: "The gearing works both ways." Yes it in fact does. It is also a fact that by changing gear ratios and other parameters you can make it work both ways in practice. So the question then is which direction does the torque actually come from in practice given the plans spork published?

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. So now all we have to do is increase prop speed at the same rate and the craft speed and the same relative condition persist. The prop therefore continues to be powered by the wheels and the prop speed only increases enough to maintain exactly the same wind differential even as the craft gains speed. Just because it exceeds ground wind speed does not mean it exceeds wind speed relative to the craft, due to the prop.

The way I got through this part in my thinking was to consider the drive shaft run into a ring with a flange. The drive shaft has a peg so it turns freely in the ring until it hits the flange. This mean the peg will be on one side if the wheels power the prop and on the other side if the prop powers the wheels. It can't be both at the same time unless you want to call it Schroedinger's craft, LMAO. 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. I even had to concede the Betz' Law issue to spork in a previous debate for this very reason.

Perhaps you are thinking that this is about your debate with Spork?
As far as I can see, the videos show a completely understandable and predictable trifle.

I was referring to your general arguments for a real machine.

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.

Anyway, you can use the vehicle shown in the original video.

There are few such rectifying mechanisms in this machine, but the most obvious are the wheels. Wouldn't you use low rolling-resistance wheels, as found on solar-powered craft?
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.

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.
If the propeller were also to be used to charge a battery and then drive a motor, would that qualify as a contender ?

 

[fsol]

Why am I getting a completely innaccurate remedial course in dynamics from a person so hard of thinking?



My flawed arguments and calculations resulted in a very real vehicle that does exactly what those calculations predicted. And now that I offer you a paint-by-numbers approach to repeating these experiments yourself with little or no trial and error - I get the most bizarre lecture about how dynamics works. What I don't hear is "you're darn right I'm going to build one - and prove you wrong".

So, we can see your calculations where?

 

[.13.]

It's been established from the days of Galileo and Newton that motion is relative. There is no physics experiment, no matter how sensitive the instrument, which can determine if the road is still and the air is moving or if the road is moving and the air is still.

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?

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.So now all we have to do is increase prop speed at the same rate and the craft speed and the same relative condition persist. The prop therefore continues to be powered by the wheels and the prop speed only increases enough to maintain exactly the same wind differential even as the craft gains speed. Just because it exceeds ground wind speed does not mean it exceeds wind speed relative to the craft, due to the prop.

Why? <- refers to emphasised statement.

 

[humber]

And the video of wind-powered craft operating in a controlled constant-wind environment ?

 

[technoextreme]

Why? <- refers to emphasised statement.

I know why. He thinks propellers work in only one direction. The only reason why the cart doesn't go backwards is because the forces equalize and the cart stops accelerating. 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.

 

[humber]

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".

 

[my_wan]

Why? <- refers to emphasised statement.

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:

Direction 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.

I know why. He thinks propellers work in only one direction. <snip>

That's an impossible position to maintain as much as I stressed to you the direct connection between the wheels and the prop. The above argument demonstrates just how aware I am that the prop can go both directions but that that also means the wheels must also go the other direction running the thing backward. Turn the wheels one way the prop blows air one way. Turn the wheels the other way the prop blows air the other way. Doesn't get simpler than that.