Down wind faster than the wind

[humber]

And yet it DOES NOT do that when we do it on a flat belt. Instead it advances on the treadmill. So in addition to not reading the thread, you must have watched the video while shaving.

As opposed to admiring oneself in the mirror. Nice logical response to inquiry as usual.

But of course, John Freestone is right, you do make a fuss that it can go up hill. As is contained in his comment, and as I have told you, friction is the key, so mo' friction, mo' better. Up hill = good.

 

[Michael C]

Note that this does have real wind, which makes them really stupid if you are right, so there would be no point in listening to them, would there? Take your pick.

This works both with and without "real wind". Do you honestly believe that a treadmill without "real wind" is useless, and one with "real wind" is useful?

 

[humber]

This works both with and without "real wind". Do you honestly believe that a treadmill without "real wind" is useless, and one with "real wind" is useful?

In the no wind case, it is a dyno.

 

[spork]

Nice logical response to inquiry as usual.

There was no inquiry. There was the claim that we faked it.

But of course, John Freestone is right,...

Well John, if this isn't enough to make you change your mind, you can't be helped.

 

[humber]

Jodn Freestone
I should be careful, having just made such a silly mistake, but at the moment I can't think of any other explanation. My guess is that it must be a fake."

Phew!. There's a blistering attack. Also you will note, that the remainder contained no supporting remarks, but spoke only of how stupid you were, and how you should get out more.

Odd, that you should think I did the same, especially when made in denial that the videos were outright fakes.

It seems that you have chosen.

 

[Myriad]

The demonstrator made a big thing about the treadmill being angled, with the model driving itself up the slope, but if it weren't trying to roll down the slope with gravity, it would just travel along with the belt and fall off the end. He even pushes against it. Of course, this push helps it to stay in one place, while the wheels are turned. Once it's got going, it may drive itself faster than the treadmill via the prop.

John, in some of the videos it's a little difficult to see which way the treadmill is going. The above comments make it sound like you're seeing the treadmill moving up the slope, that is from left to right (as I did when I first viewed one of the treadmill videos). The treadmill is actually moving down the slope, right to left. So if the humbercraft didn't have net thrust in the left to right direction, up the slope, both gravity and the treadmill's movement would be sending it off the downhill left end of the belt.

Respectfully,
Myriad

 

[humber]

John, in some of the videos it's a little difficult to see which way the treadmill is going. The above comments make it sound like you're seeing the treadmill moving up the slope, that is from left to right (as I did when I first viewed one of the treadmill videos). The treadmill is actually moving down the slope, right to left. So if the humbercraft didn't have net thrust in the left to right direction, up the slope, both gravity and the treadmill's movement would be sending it off the downhill left end of the belt.

Respectfully,
Myriad

Myriad, as I have said before, the humbercraft would make a much better job of it.
But you also know, that I do say that there is a net forward force, but that it is small, and not enough to move a cart in real wind.

Two conditions apply for your remark to stand.
1. There must be a means of producing adequate force to send it of the end. In this case, there is not, because any additional torque cancels it self out as I have previously described.

2. Both the acquisition of force, and the propulsion of the cart require adequate friction.

The ease of movement of the device upon the belt - in fact is skids about - support both those contentions.

Your faithful servant,
Humber

 

[spork]

You sure do spout one helluva lot of pseudo science B.S. when you could just build one of these things yourself for $40. But I guess the real world doesn't count unless it's faithful to your bizarre notions of the laws of physics.

 

[ynot]

What I believe adds to the confusion and creates suspicions is the relatively poor level of test demonstrations offered. There seems to have been a lot more effort and attention given to construction the cart than to the testing of it.

At the very minimum the cart should be set up on the treadmill so that it doesn’t need to be “interfered” with by human hands at all. Only guides, stops and strings should be used to keep the cart under control.

 

[spork]

What I believe adds to the confusion and creates suspicions is the relatively poor level of test demonstrations offered.

We went to a good deal of trouble to show everything we possibly could, and even made and posted a number of videos in direct response to our critics.

At the very minimum the cart should be set up on the treadmill so that it doesn’t need to be “interfered” with by human hands at all. Only guides, stops and strings should be used to keep the cart under control.

I look forward to seeing your video of this test when you've built your cart.


One of our videos shows the cart "hovering" on the treadmill on a positive incline for 1 min, 48 seconds without any interference from anything. If people wish not to believe I'm confident they'll find a reason.

 

[Michael C]

Don’t have much time right now but here are a few quick things that helped me understand how the principle works . . .

The wind is pushing against the reverse wind created by the propeller and not the cart or propeller.

When the cart is moving at the speed of the wind this reverse wind is effectively moving in the direction of the wind slower than the cart and wind so the wind can still push on it.

This is the way I first overcame my skepticism. It may be a simplification, but it's a good step on the way to understanding what is going on. My first, hasty reaction to the video in the OP was "Hey, that can't work. There must be something pulling it". Then I started trying to analyse what was going on and very quickly began to have doubts. When I realised that the prop was turning in the opposite direction to the direction it would turn it you lifted the cart off the ground to let the wheels spin, the penny dropped.

The speed of the propeller comes from the relative speed of the cart and ground and not the cart and wind.

That's exactly it. There is a direct relation between the speed of the propeller and the speed of the cart along the ground. And the important thing about the speed of the propeller is that its effective speed through the air in the direction of the cart's movement is slower than the speed of the cart along the road. It took me a while to get my mind around this, but the purely mechanical models (no air involved) helped here.

 

[spork]

A rare and accurate description. Thanks Michael.

 

[John Freestone]

Several of us have now demonstrated this and have posted videos of same. You are showing yourself to be a fool by jumping in with both feet (in your mouth) without even having read the thread.

That's just me, spork. I just jump in sometimes and say what I feel like saying and I don't give a fillet of fish if it turns out I'm talking rubbish. I feel that having started by saying I thought it was an amazing reality, then realised I was wrong, my freedom to change my mind and my openness about being wrong would be clear. I was excited about the thread and jumped in because I thought I'd spotted the relevant facts, and I wasn't prepared to wade through 32 pages of discussion first. It was then only fair to post again to say I'd realised my 'schoolboy error'. If I am now still wrong and you demonstrated it and have videos and all that, well time will prove that. Big deal. Pardon me for sharing my opinion.

That you choose to call our credibility into question because of your own lack of understanding is shameful. Fortunately, no one here puts any weight behind your words as you've admitted to jumping in with a conclusion without understanding what's being claimed.

Please don't speak for other people. Others might take my words as informative, for all you know, and it is not shameful for me to state that I cannot understand how such a vehicle could possibly do what has been claimed, if that is that a purely wind-powered vehicle is able to move continuously directly downwind faster than the wind powering it, and, that being the case, that I could not think of a better explanation for the video I watched.

Well, I guess it's off to another thread for you - so you can offer your opinion on other matters you don't understand - and then move on.

Good grief, no. This is fascinating!

Did you study intuition or physics?

Er, both, though my physics is a long time ago and only up to the British A level, and a year of foundation physics for my geology degree, which I didn't complete. I am sorry if you object to me jumping in at this stage, and I will spend a while reading from the beginning, but if you would be so kind I would love you to summarize briefly what is wrong with this objection:

The vehicle described has as its sole source of energy the passage of a steady wind from the rear. It accelerates directly downwind. As it accelerates, the passage of wind is reduced proportionally. Hence, if it were to reach windspeed, there would no longer be any relative wind speed past the propeller or any part of the vehicle. Hence there would be no additional source of energy. Similarly, if I blow a piece of paper across the table, it cannot go faster than my breath is blowing. There is some drag, and in fact it goes slower. Now, it does not matter in the slightest what magical engineering feat of origami I might be able to perform with that piece of paper. If its sole source of energy is the wind moving past it, then as it increases in speed, that reduces, towards a theoretical zero when it is moving at windspeed.

What if we'd tested it in a very long wind tunnel? Would you insist we unplug the fan? What if we'd tested it outdoors? Would you insist we do it when the wind is not blowing - despite this being a wind powered vehicle!?

No, you're going off at tangents here. I was suggesting that little insight is to be gained on the matter of whether this wind-powered machine does go faster than the wind or not by putting it on a separately powered treadmill to drive its wheels. However, perhaps this is to demonstrate some clever bit of physics I don't know about yet. It just strikes me as rather odd, like if I said I had a solar powered flying house brick, and as one of my demonstrations offered a video of me lobbing it off a cliff.

And yet it DOES NOT do that when we do it on a flat belt. Instead it advances on the treadmill. So in addition to not reading the thread, you must have watched the video while shaving.

No, I only read books while shaving. I don't want to get an electric shock.

 

[ynot]

We went to a good deal of trouble to show everything we possibly could, and even made and posted a number of videos in direct response to our critics.



I look forward to seeing your video of this test when you've built your cart.


One of our videos shows the cart "hovering" on the treadmill on a positive incline for 1 min, 48 seconds without any interference from anything. If people wish not to believe I'm confident they'll find a reason.

I’m not saying your test demonstratioins are so bad that they are worthless and they are part of what convinces me that the claim is valid. Although understanding the mechanics involved is the main convincer and I wouldn't accept on your videos alone. I’m merely saying that they could be done better. You have never (to my knowledge) shown a test where someone isn’t manually poking and proding the cart or where the speed of the treadmill speed is gradually increased from standstill with the cart on it.

I think my suggested test of having the cart tethered on a string from the top end of the treadmill would be more credible and believable than the tests you have provided. The cart should be placed toward the lower end of the tread (but not to close to the roller) before the treadmill is turned on. The treadmill should be started at the slowest speed and gradually sped up to the point where the thrust of the fan just exceeds the rolling resistance of the wheels and the string becomes slack. This would prove no stored energy is being used. Then speed the treadmill up faster so the cart advances against the motion of the tread. Ideally the tread should have a slight uphill angle.

Obviously you are under no obigation to do such a test and I certainly don’t need to see it to be convinced. It may help others to become convinced however and may remove some of the criticisms of your current tests. You have the cart and treadmill and a piece of string shouldn’t be to hard to find and it wouldn‘t take much time to do. I don’t have a working cart and I really don‘t have the time to build one as this is the busiest time of the year for my business. Your cart demonstrates the principle on a treadmill adequately enough for myself so if I was going to invest more time and money building a test cart it would probably be a larger one for outside wind use as I don‘t think this has been adequately done as yet. I like the idea of fitting the system to a racing bike and pedaling downwind to the speed of the wind and see if I then go faster. The real wind speed would be made apparent with a stream of bubbles.

ETA - You might also like to consider doing a test with a bit more weight added to your cart.

 

[John Freestone]

Welcome to the discussion John.

Thanks, Dan.

Before you read the rest of this thread, how about entering into a bit of a wager? Since JREF probably frowns upon using it's site for gambling, this is what I propose we do...

Let the believers and non-believers put up equal sums of money to back their belief. We'll then enlist the services of the JREF staff to test the device to see if it performs as claimed. The losers pay their wager as a donation to JREF.

[As a bonus, if JREF can be convinced beforehand that the device must be violating the laws of physics in order to perform as claimed and therefore qualifies for the MDC, All parties will split the $1M prize money.]

Unfortunately, I do not like to gamble on principle*, otherwise I would take you up on this. OTOH, I will eat my hat if this thing can do what I think is being claimed, and independent qualified engineers verify it to my satisfaction. I'm happy to post a photo of my hat...and, if I'm wrong, a video of me eating it.


*The principle of not liking to lose money.

 

[Thabiguy]

... but if you would be so kind I would love you to summarize briefly what is wrong with this objection:

I can give you such a brief summary, if you don't mind me doing it.

The vehicle described has as its sole source of energy the passage of a steady wind from the rear.

This may be misleading. The source of energy is the steady wind from the rear, but in this case, it's important that wind is relative motion of air with respect to the ground - not just with respect to the vehicle.

It accelerates directly downwind. As it accelerates, the passage of wind is reduced proportionally.

Correct.

Hence, if it were to reach windspeed, there would no longer be any relative wind speed past the propeller or any part of the vehicle.

Not correct. When the vehicle reaches windspeed, the propelling assembly is "moving forward" at less than windspeed. This is not so easy to see with the propeller version, but very easy to see with many other devices utilizing the same concept that have been presented - and illustrated - throughout this thread.

Note that this only works because the device is in non-sliding contact with the ground.

Hence there would be no additional source of energy.

Not correct. Even at windspeed, there is still a source of energy for the vehicle - the relative motion of the air and the ground. The vehicle has interfaces to both (this is of crucial importance) and is thus able to exploit that difference.

Similarly, if I blow a piece of paper across the table, it cannot go faster than my breath is blowing. There is some drag, and in fact it goes slower. Now, it does not matter in the slightest what magical engineering feat of origami I might be able to perform with that piece of paper. If its sole source of energy is the wind moving past it, then as it increases in speed, that reduces, towards a theoretical zero when it is moving at windspeed.

All correct. However, this is true because the piece of origami has no contact with the ground (or any other medium moving with respect to the air). If it had contact to such medium, what you wrote would no longer be true and the origami could in fact move faster than your breath is blowing.

OTOH, I will eat my hat if this thing can do what I think is being claimed, and independent qualified engineers verify it to my satisfaction. I'm happy to post a photo of my hat...and, if I'm wrong, a video of me eating it.

It's impressive that you're willing to do that, but perhaps you could choose something else to do that would pose less danger to your health.

 

[spork]

EDIT: I see that thebiguy has beat me to the punch. I haven't read his response yet, but I'm sure it's every bit as accurate and 7 dB less sarcastic than mine. Read on if you care to.

Big deal. Pardon me for sharing my opinion.

I have no problem with anyone sharing their opinion or skepticism. I felt you were telling us "fact" and calling our intelligence or integrity into question. If I'm wrong - sorry. I don't plan to even look back at the posts.

it is not shameful for me to state that I cannot understand how such a vehicle could possibly do what has been claimed

No, it's shameful to state that you do know when you do not - and then take pokes at those that do. Again - maybe that's not what happened.

I am sorry if you object to me jumping in at this stage...

I don't mind one bit. And if you jumped in asking questions you'd have gotten answers. I don't want to cover the other part again in this post.

...but if you would be so kind I would love you to summarize briefly what is wrong with this objection

I'll be happy to. But you have to promise to pay attention. I originally posed this as a brainteaser for a reason - you're supposed to get the wrong answer.

The vehicle described has as its sole source of energy the passage of a steady wind from the rear. It accelerates directly downwind. As it accelerates, the passage of wind is reduced proportionally. Hence, if it were to reach windspeed, there would no longer be any relative wind speed past the propeller or any part of the vehicle.

You were right until the end. At wind speed there will be no passage of wind over the vehicle - and no passage of wind across the disk of the prop. But the blades of the prop are going crosswind just as fast as they're going downwind - the wheels and trasnsmission provide the necessary kinematic constraint to ensure this. At this point the tips of the prop blades are exactly analogous to an ice boat on a 45 degree downwind tack in which it's downwind velocity component is equal to the wind speed (ice boats can achieve steady state downwind velocity components of 3 to 4X wind speed).

Similarly, if I blow a piece of paper across the table, it cannot go faster than my breath is blowing. There is some drag, and in fact it goes slower. Now, it does not matter in the slightest what magical engineering feat of origami I might be able to perform with that piece of paper. If its sole source of energy is the wind moving past it, then as it increases in speed, that reduces, towards a theoretical zero when it is moving at windspeed.

You're right that a piece of paper in just about any shape will never outpace the wind. However, I don't know how good your origami skills are. If you manage to make a vehicle that can exploit the energy available at the ground/air interface and leverage that into speed over force, maybe you can achieve that goal. But you'd have to have a black-belt in origami.

No, you're going off at tangents here. I was suggesting that little insight is to be gained on the matter of whether this wind-powered machine does go faster than the wind or not by putting it on a separately powered treadmill to drive its wheels.

I'm not going off on a tangent at all. I'm responding directly to your criticism of the treadmill. The principle of equivalence of inertial reference frames tells us that a moving road in still air is identical to a still road and moving air. How I power the road or the wind is not material.

 

[spork]

I’m not saying your test demonstratioins are so bad that they are worthless.

We did these tests and videos precisely because people made such claims about Goodman's video. I'm sorry you don't find them convincing. However, we've also offered to ship our vehicle to skeptics to test for themselves, posted the parts and build plans for a vehicle you can make in a couple of hours for $40, and even offer to sell you the complete parts kit at our cost. If we're pulling a scam, it's a darn poor one.

You have never (to my knowledge) shown a test where someone isn’t manually poking and proding the cart

That's your fault, not mine. We posted a video in which the car is left alone for 1 minute, 38 seconds, and I've mentioned it repeatedly. And I'm sure I'll have to continue mentioning it.

I think my suggested test of having the cart tethered on a string from the top end of the treadmill would be more credible and believable than the tests you have provided.

Perhaps they will be more believable to you. I assure you anything involving a string or tether of any sort will be less believable to others.

So it sounds like you've changed your mind and don't want a set of parts. I'll remove you from the list.

 

[John Freestone]

I can give you such a brief summary, if you don't mind me doing it.

Thank you Thabiguy...

This may be misleading. The source of energy is the steady wind from the rear, but in this case, it's important that wind is relative motion of air with respect to the ground - not just with respect to the vehicle.

I disagree. As far as the energy input to the vehicle is concerned, it is solely the vehicle's windspeed, IMHO. For a stationary electricity generating wind turbine, the two are the same thing, but if somehow the turbine moved to track the wind perfectly, it would experience no wind at all and stop turning. The wind speed relative to the ground would remain the same.

Not correct. When the vehicle reaches windspeed, the propelling assembly is "moving forward" at less than windspeed.

I don't understand. The propelling assembly - prop, it's mounting? - they are part of the vehicle and are not "moving forward" or backward, relative to the rest of the vehicle, surely? When the vehicle reaches windspeed (which it won't, as I've said) its propeller assembly is (would be) moving at windspeed. If it were moving forward at less than windspeed, it would fall off the back of the vehicle, surely?

This is not so easy to see with the propeller version, but very easy to see with many other devices utilizing the same concept that have been presented - and illustrated - throughout this thread.

Thanks, I'm almost at the bottom of page 1 now!

Note that this only works because the device is in non-sliding contact with the ground.

Ok. Let me see if I can get my head round how this might work: The prop isn't a wind turbine, translating the wind energy into rotation of the wheels to drive the thing forward; the vehicle is pushed forward more by the wind hitting the flat of the blades and rest of the vehicle (and sometimes a reasonable little starting push, maybe, that's not a problem). The motion of the vehicle forward over the ground drives the wheels, which in turn rotates the propeller. This would explain why in the road test video of J Goodman's machine, the blades seem to be angled to drive like a plane's propeller, not be driven by the passage of the wind. Is that the theory? Hmmm...interesting if it is. I'm still concerned about whether the wind pushing it could create enough power in that way to "push back against the wind" so to speak, but I guess I'm less confident. Warming my hat.

Not correct. Even at windspeed, there is still a source of energy for the vehicle - the relative motion of the air and the ground. The vehicle has interfaces to both (this is of crucial importance) and is thus able to exploit that difference.

Ok. Maybe. You see, I was going to object that the 'interface' with the ground is only of rolling resistance and can only slow the vehicle, but I was working on the idea of a turbine driving the wheels, and maybe that's wrong. Iif the other scheme is what you're saying happens, it could perhaps be the other way round: the force of pushing the machine across the ground would 'interface' with the wheels in a driving sense, like when you push a wind-up toy on its spring-loaded wheels - it adds energy to the system. I think it must depend on whether this is possible - that the wind pushing it can generate extra energy that can be used to push back against the wind - which still sounds rather like 'perpetual motion' or pulling oneself up by the bootstraps, to be honest, but maybe that's possible.

All correct. However, this is true because the piece of origami has no contact with the ground (or any other medium moving with respect to the air). If it had contact to such medium, what you wrote would no longer be true and the origami could in fact move faster than your breath is blowing.

Yes that fits with what you seem to be suggesting, or what I've made of it. Anyway, let's forget origami. If that kind of thing is how it's supposed to be working, then I apologise, at least for misunderstanding the fundamental workings of it. Whether it works is another matter.

It's impressive that you're willing to do that, but perhaps you could choose something else to do that would pose less danger to your health.

Ok. Since I find myself a little less sure again, I'll take that as a serious warning! You're medically qualified. And my hat is quite big and probably poisonous.

 

[spork]

For a stationary electricity generating wind turbine, the two are the same thing, but if somehow the turbine moved to track the wind perfectly, it would experience no wind at all and stop turning.

Yeah, but if it were on wheels you could still harness that energy with a generator attached to the wheels. You can get it from the air, the ground, or both. Our vehicle uses both.

When the vehicle reaches windspeed (which it won't, as I've said)...

And yet it does - and continues to accelerate.

its propeller assembly is (would be) moving at windspeed. If it were moving forward at less than windspeed, it would fall off the back of the vehicle, surely?

Did you read my post explaining the cross-wind component of the prop tips and how that motion is constrained by the wheels?

Ok. Let me see if I can get my head round how this might work: The prop isn't a wind turbine, translating the wind energy into rotation of the wheels to drive the thing forward; the vehicle is pushed forward more by the wind hitting the flat of the blades and rest of the vehicle (and sometimes a reasonable little starting push, maybe, that's not a problem). The motion of the vehicle forward over the ground drives the wheels, which in turn rotates the propeller. This would explain why in the road test video of J Goodman's machine, the blades seem to be angled to drive like a plane's propeller, not be driven by the passage of the wind. Is that the theory?

That's correct with one key correction... once the prop gets spinning it acts like a prop - not like a bluff body.

>>... but I guess I'm less confident. Warming my hat.

You should consider boiling it.

I think it must depend on whether this is possible - that the wind pushing it can generate extra energy that can be used to push back against the wind - which still sounds rather like 'perpetual motion' or pulling oneself up by the bootstraps, to be honest, but maybe that's possible.

Probably one of the key things that suggests it's not perpetual motion is the fact that it needs a continuous supply of energy to keep going.