Down wind faster than the wind

[GregLondon]

Your first paper was clearly condescending and showed a picture of the debate that was not even close to the one I have seen so I can't see your point at all.

No point really. In the end, I admitted when I was wrong. I apologized to spork at one point. (or twice. or thrice.) He wouldn't have any of it. I rewrote my paper. And he's carrying around some sort of weird grudge about it, like I've done him irreparable harm or something. Then I make a pretty short post here pointing to a completely neutralized version of my document and no where to I even mention spork, and he comes out slinging mud about how big of a meanie I am. Meanwhile, he's gotten a number of threads locked for his behaviour on this topic. And he was definitely combative on the forum I was on, and unapologetic about it.

I can be an ass. And I can apologize for it. I don't need lessons in ettiquette from someone who can't actually demonstrate it. When spork goes back through all the threads and apologizes to all the people he's been a jerk to, then he can give advice about it.

That's all I was saying.

 

[ThinAirDesigns]

Don't make me drag out the "Greg London Greatest Hits" compilation post -- along with this supposed apology.

After his performance in this document, Greg is the last guy in the world you would want involved in an engineering decision where "people die" if you screw up.

The hubris was just amazing ... 'I don't need to test because I understand it soooo well and I impose scientific rigor' blah, blah, blah. All the while blusteringly presenting a design that defied the laws of physics he so haughtily claimed to know and repeatedly belittling our device and knowledge of it.

We ended up having to do the test of his design that because of his 'critical systems' engineering experience he 'didn't need to do'.

http://www.youtube.com/watch?v=axoflkkwwyI

What a 'critical systems, lives on the line, people die, scientific and engineering rigor' hoot this guy is.
JB

 

[ynot]

No point really. In the end, I admitted when I was wrong. I apologized to spork at one point. (or twice. or thrice.) He wouldn't have any of it. I rewrote my paper. And he's carrying around some sort of weird grudge about it, like I've done him irreparable harm or something. Then I make a pretty short post here pointing to a completely neutralized version of my document and no where to I even mention spork, and he comes out slinging mud about how big of a meanie I am. Meanwhile, he's gotten a number of threads locked for his behaviour on this topic. And he was definitely combative on the forum I was on, and unapologetic about it.

I can be an ass. And I can apologize for it. I don't need lessons in ettiquette from someone who can't actually demonstrate it. When spork goes back through all the threads and apologizes to all the people he's been a jerk to, then he can give advice about it.

That's all I was saying.

Just ignore Spork & Co as I do. They really aren’t that important to the debated even though they have introduced the debate to many forums. It was never “their idea” and they haven’t really offered much more to the debate than others have offered before them or since. They spend more time insulting and trying to discredit people than they do debating the actual principle. One of the things that made me question that the principle was genuine was the unnecessarily insulting way they treat people who dare to question not so much the principle, but their superior knowledge. Why they do this is anyones guess but a clue might be found in Spork’s own words . .

When I asked what practicle use the principle might have Spork replied - “The only practical application it has is to start pissing matches on internet forums. And for that it has no equal”.

His avatar on one of the many another forums he insults people on reads - “Fear the Spork”.

This guy is apparently employed as a science advisor to a large Silicon Valley business!

 

[ThinAirDesigns]

Ynot:

Just ignore Spork & Co as I do.

You have no idea how funny that is Ynot, considering how often you say it followed by your complete and absolute inability to "ignore Spork & Co"

Laugh Riot.

JB

 

[GregLondon]

thinair, is there anything that would reconcile you? Do you need me to post something publicly? send you a private email with some kind of specific apology? What would it take?

 

[John Freestone]

Hi Greg

Tumbleweed - that was the no-moving-parts cylinder thing, right? I had a scan through your paper. Welcome. I will try not to get involved in the personal stuff on this.

There's an interesting question left hanging for me, which is whether it is possible to build a DDFTTW device with no moving parts (in the sense, obviously, of not moving with respect to any other parts). I can't see a way, myself, but it might be an interesting challenge to bang one's head on for a while.

I wasn't enough of an expert to predict whether your tumbleweed design would work or not with confidence before I saw it tested, but it looked decidedly unlikely, certainly at the kinds of windspeeds spork & JB tested it at on a treadmill. Pardon me if I've missed a lot, and particularly if you dispute that they tested a significantly correct version, their results, or whatever. I'm just hoping I'm not being a complete dipstick and mixing you up with someone entirely different.

This also raises another question: could the device beat the wind at faster windspeeds? Less efficient carts with props need higher windspeeds to generate the sufficient mechanical advantage or whatever it might be called by the tech-heads round here, and the curved surfaces of the fins suggest that there might be some windspeed at which it could work. Obviously, if it works, but hasn't met a sufficiently fast wind yet, that would also answer the first question.

 

[spork]

thinair, is there anything that would reconcile you? Do you need me to post something publicly? send you a private email with some kind of specific apology? What would it take?

A few points worth noting Greg...

First, I have NEVER insulted anyone on any forum without first having been attacked.

Second, the physics threads were locked because no one on the physics forums understands even the most basic principles of physics (with the exception of Russ Waters who eventually understood the principle of equivalence of inertial frames). The physics forum is an astonishing group of humbers.

Third, your behavior on BoingBoing was astonishingly insulting, condescending, and WRONG.

Finally, you claim to have offered an apology (or two or three), but they were basically of the form "sorry you weren't man enough to take my insults".

There are several people that have outright attacked JB and myself over this thing (some on this forum). They've offered sincere apologies, and we've put it completely behind us. Do you honestly want to dredge up your record of abuse and wrongness again?

 

[spork]

There's an interesting question left hanging for me, which is whether it is possible to build a DDFTTW device with no moving parts

John, I'm almost certain it's not possible to build a DDWFTTW vehicle with no moving parts. But I can answer your other questions more definitively. Yes, the "tumbleweed" in question is Greg's design. And No, it cannot work, not even in theory, at ANY wind speed. Sadly, if I understand correctly, that means a lot of people will die horrible fiery deaths.

 

[John Freestone]

John, I'm almost certain it's not possible to build a DDWFTTW vehicle with no moving parts.

Gosh. That's quite tempting, the almost-certainly impossible. I'll sleep on it and have one for you by breakfast.

But I can answer your other questions more definitively. Yes, the "tumbleweed" in question is Greg's design. And No, it cannot work, not even in theory, at ANY wind speed.

Thanks, spork.

 

[GregLondon]

Tumbleweed - that was the no-moving-parts cylinder thing, right? I had a scan through your paper.

yep. my first version was teh no moving parts cylinder.

Pardon me if I've missed a lot, and particularly if you dispute that they tested a significantly correct version, their results, or whatever.

The latest version of my document says that no-moving-parts cylinder doesn't work. If you read an older version, click on my username and go to my website for the latest rev. Somewhere in my latest rev I describe my first design as teh no-moving-parts cylinder and then show why I was wrong and why it doesn't work.

There's an interesting question left hanging for me, which is whether it is possible to build a DDFTTW device with no moving parts

I don't know if it's possible or not. I came up with a strange design that only has two moving parts total. but it would be a machining challenge to actually try and build it. ANd it would be extremely difficult to balance. It's hard to describe in text.

One part would consist of a "wheel" that is two pieces of metal bolted together through the axle. In between these two pieces, you'd have to machine gear teeth that go around the axle. the two pieces might look like "dualies" on a truck. Two "tires" side-by-side. On the "sidewalls" of the tires in betwen the tires, you'd have to machine some gear teeth that go around the axle.

The second moving part is a propeller on a horizontal shaft with a gear that engages the teeth between teh tires. The shaft would have the propeller in back, the gear in the middle, and part of the shaft woudl stick out front wtih a counterweight so that the second piece's center of mass is right where the gear teeth contact the tire. So that the thing doesn't want to roll over from its own weight. So you could place it on the ground and it won't roll over and push the prop into the dirt.

And the gear teeth on the tire would have to curve around the gear of teh prop shaft so that it can hold the shaft up, but the gear teeth would have to have a gap big enough for the shaft itself to stick out fore and aft.

Trying to get it to move would be hard too. You couldn't just put it on a treadmill because the prop needs to be spinning and if it isn't the prop will just spin around and gouge a hole into the rubber. ANd there isn't anything to hold onto, cause there's no stationary part of the device.

If it starts out stationary and you put a tailwind behind it, you might be able to get the prop to spin and that would cause the prop and shaft to rotate along the shaft but also "climb" up the teeth on the tires. When the prop "climbs", it moves the center of gravity of the whole object and the tires rotate forward, bringing the prop back down to horizontal.

You'd probably have to put it on the ground in a controlled windtunnel, and slowly bring up the windspeed until it started moving and then adjust the speed to make sure the propshaft doesn't climb right into a rollover. Once you get over a certain speed, the prop starts working efficiently and the power on the prop is much greater than the friction between teh gears (the only point of friction in this design), and there should be a steady state point where it is going faster than the wind.

If it would work at all. Like I said, building it would be hard. And getting it from zero to steady state wouldn't be easy either. And in the end, you don't really get anything other than a design with only two moving parts but is harder to build and operate than other designs with five or ten moving parts. So I stopped working on the idea much more than that.

Not that any of this has much practical value, but anyway.

 

[GregLondon]

Originally Posted by GregLondon

thinair, is there anything that would reconcile you? Do you need me to post something publicly? send you a private email with some kind of specific apology? What would it take?

Do you honestly want to dredge up your record of abuse and wrongness again?

I'm not sure how you got from "what would it take to reconcile you" to "dredge up my record".

They've offered sincere apologies.

I'm not sure what you mean by a "sincere" apology such that "I'm sorry" doesn't qualify.

and we've put it completely behind us

Hm, why is it I"m having a hard time believing you?

Sadly, if I understand correctly, that means a lot of people will die horrible fiery deaths.

sarcasm duely noted.

I have NEVER insulted anyone on any forum without first having been attacked.

And if you don't get a "sincere" apology, you will return that first insult with a lifetime's worth of insults? You know, at some point, the "he started it" bit wears off, and the continued "insults in return" start becoming brand new insults all their own.

I'm sorry for my abusive behaviour on the BoingBoing thread.

You can either accept that as "sincere" or not. But either way, I'm not taking continued abuse from you.

If there is something specific you need to reconcile whatever you need to reconcile, beyond a "I'm sorry for my abusive behaviour on BoingBoing", you're going to have to let me know and maybe I can give it to you. If you're irreconciliable, then you're irreconciliable. Either way, at some point the "I only attack after someone attacks me first" loses its credibility when you keep the "counter" attacks going months later.

 

[spork]

I'm sorry for my abusive behaviour on the BoingBoing thread.

That's the first genuine apology I think I've heard from you. And as far as I'm concerned it's behind us now. I'd much rather discuss the merits and methods than to have the pissing match.

Without further insult from you, you won't hear more from me.

 

[Dan O.]

That's the first genuine apology I think I've heard from you. And as far as I'm concerned it's behind us now. I'd much rather discuss the merits and methods than to have the pissing match.

Without further insult from you, you'll won't hear more from me.

Thanks spork, now I don't have to warn everyone about the civility requirements on this board. The management here doesn't often lock threads because it is rarely the thread that is misbehaving. Instead, they tend to lock the abusive posters; often preceded by a warning to attack the argument not the arguer; which is somewhat puzzling since they then proceed to attack the arguer in the form of suspensions and banning and let the arguments stand.

 

[John Freestone]

yep. my first version was teh no moving parts cylinder.



The latest version of my document says that no-moving-parts cylinder doesn't work. If you read an older version, click on my username and go to my website for the latest rev. Somewhere in my latest rev I describe my first design as teh no-moving-parts cylinder and then show why I was wrong and why it doesn't work.

Oh good, I got the right bod. Pity about that, it's a nice design.

I don't know if it's possible or not. I came up with a strange design that only has two moving parts total. but it would be a machining challenge to actually try and build it. ANd it would be extremely difficult to balance. It's hard to describe in text.

<snip>

Not that any of this has much practical value, but anyway.

Yes, I think you've described that well enough to get the general picture, and it's interesting in how it uses gravity and its own weight to develop torque.

So that's two separate parts moving relative to each other. Hmmm. This could develop into a little side issue of its own. I slept on the problem, but didn't manage anything with no moving parts. [ETA: I think it's probably better to call that a 1-part cart, and not just because it rhymes, but it's the same thing, since you can't have one part moving relative to itself - well, we know someone who could, but that's another story.]

I think I've also invented a 2-part DDWFTTW machine. I can hear the fanfare now. The phone hasn't stopped. I'll post a diagram and details later.

 

[ThinAirDesigns]

I'm sorry for my abusive behaviour on the BoingBoing thread.

That's the first of the sort that I've seen and it's much appreciated and accepted. Really.

Carry on.

JB

 

[John Freestone]

Here's my attempt at a two-part DDWFTTW cart for criticism and general discussion, with an alternative version too. There are lots of variables to play with - the length, number and type of vanes, radius span of the vanes, mass and shape of counterweight, etc.

There is also another completely different way to do this, putting the cylinder on an axle that goes through the cowl, then with a wheel on each side, outside the cowl. I chose this version, using the possibly dodgy trick of what I've called a pin-bearing, because putting the axle through the cowl makes it more likely to require a proper bearing with its own moving parts, and I was trying to go purist. The cowl ought to be constructed with just the right amount of give so that it can be sprung over the pointy ends of the pins, which should hold everything in place.

I can't see any problem with this or a very similar design, but I might be way off. I'm not sure if anyone else has invented it before me, and I have to say that although it was my own idea, it's the result of putting various other ideas on the DDWFTTW threads and elsewhere together. In particular, it's very little other than Greg London's Tumbleweed device with the cowl added (which I am hoping solves whatever theoretical problem there was with that, while sacrificing a 'moving part' - his was an attempt to make it all in one).

If it does work, I have to thank Greg also for the last bit in the puzzle. I had got a three-piece machine by just putting the cowl over from a chassis, and putting another axle and tailwheel or nosewheel on, until he posted his 2-part idea with a geared prop, which depends on a counterweight. Then I realised that I could do the same thing with a simple cowl. I guess the diagrams and little bit of text is enough.

until I get some feedback from the aero and mech experts round here.

The first I thought might be a little unstable in the wind, hence the more symmetrical lozenge shaped one after. Of course, a simpler version still would be just to put a simpler circular-arc-shaped cowl on without the streamlining. Spork - you might even be able to knock something up from your Tumbleweed and a tin can!

 

[GregLondon]

John, If I understand your design, when your cart is going at the exact same speed as the wind, the cowl doesn't do anything (because at the speed of the wind, there is no air flowing over the cowl), and its just a fixed vane wheel, which can't go faster than the wind.

 

[ThinAirDesigns]

John, If I understand your design, when your cart is going at the exact same speed as the wind, the cowl doesn't do anything (because at the speed of the wind, there is no air flowing over the cowl), and its just a fixed vane wheel, which can't go faster than the wind.

Greg has nailed your problem John. Unless you can somehow make the vanes under the cowl operate in a vacuum, you're more screwed the close you get to windspeed.

The cowl doesn't prevent the simple 'churn' that your vanes engage in at windspeed -- in fact, I'd bet that a design without a cowl will go faster in the wind than one without due to interference drag (but that's just a guess).

JB

 

[John Freestone]

John, If I understand your design, when your cart is going at the exact same speed as the wind, the cowl doesn't do anything (because at the speed of the wind, there is no air flowing over the cowl), and its just a fixed vane wheel, which can't go faster than the wind.

Greg has nailed your problem John. Unless you can somehow make the vanes under the cowl operate in a vacuum, you're more screwed the close you get to windspeed.

The cowl doesn't prevent the simple 'churn' that your vanes engage in at windspeed -- in fact, I'd bet that a design without a cowl will go faster in the wind than one without due to interference drag (but that's just a guess).

JB

Oh. That's disappointing. It's very annoying actually, because my intuition was that the churning effect would make this not work, but I confused myself with a little knowledge, maybe, or possibly someone else misguided me. I've been trying to track the posts down. At #1412 in this thread, when I had realised that my main objections to DDWFTTW were false, but I was still on the fence and looking at the various analogies, I said:

In the hypothetical version someone described (sorry, forgot who just now) with two wheels, the top one geared at half speed of the ground wheel, and driving the whole by vanes attached to that upper wheel, it was supposed to work because only the top half of the vanes were exposed to the wind. Presumably we can't expose the bottom half going in the wong direction (forwards, relative to the vehicle, I think), and faster than the vehicle.

Never mind, you put it in a bit of a barrel shaped cowl, was the answer. But then I wonder, how is it that those paddles moving round inside the cowl in the wrong direction don't still suck air backwards through their protective casing anyway, and all that supposed advantage be lost again?

I said "described", but I thought there was also a diagram of a circle of vanes on a wheel, the bottom ones (in this case) shrouded from the air supposedly for the same reasons the top ones are in my design. [ETA: sentence corrected]

Unfortunately, in all the things I was getting wrong and being corrected on, I thought this was one of them. I thought someone corrected that point, but I haven't found it. Maybe it just got passed over.

I presume that I've described it well enough - the cowl "hugs" the vanes over the top half or more, like they're spinning in a tin can (it's not that clear in the drawing), so that only the lower vanes are exposed to the direct flow of the wind. JB, that seems to be what you're saying, you understand that, but it will suck the air in anyway, so the cowl is useless (worse than), but you also say that Greg has nailed the problem, and Greg's description seems nothing to do with the air being sucked back in and churned round the vane.

Greg, I realise that the cowl isn't having any particular or important aerodynamic effect on the wind - it is only there to remove the effect of the vanes as they move forward. The design's intended advantage above windspeed was from the relative backward motion of the vanes under the axle position as their speed reduces, the same advantage they would have if flopping over or hinged as in one of your designs. I guess you must know that, and just haven't spelled out that the problem is that the cowl will not effectively stop the upper vanes from pushing the air backwards.

As I said, it's so annoying, because that's the belief I had coming in to all this months ago! I should have questioned that again first and not wasted half a day! Oh well. Thanks anyway.

 

[GregLondon]

Greg's description seems nothing to do with the air being sucked back in and churned round the vane.

There are probably a few ways to describe it, but yeah, when it's moving at the same speed as the wind, the cowl doesn't do anything. But air still churns around the vanes, slowing down the wheel. When it slows down, below airspeed, the vanes will accelerate it up again, but once its moving at the speed of the wind, nothing leverages it to go faster. It's no longer getting any advantage from the wind, cause its pushing on the wind all around the vane in all dirrections.

When a propeller cart is moving as fast as the wind, the propeller is still pushing air backwards (and only backwards), so it wants to accelerate teh cart faster than the wind.

hm.

I thik one way you might be able to get a one-part-cart would be if you had some stiff wire coiled like a corkscrew with a big enough diameter that you could put a propeller inside it, and then it would only work if you placed it on "ground" that was basically geared teeth. then if the prop pitch advances one inch per revolution, but the corkscrew is 1.2 inches per revolution (or 0.8, I cant figure it in my head), you might get something that would go faster than the wind.

It's either one moving piece or two, depending on whether you have to count the "ground".

Not very practical, but again none of this is really.