Monday, January 25, 2010

70> Speaking of....

The other day I was looking over Jerry Schneider’s excellent ITT website for anything new and a link caught my eye. (It had the word “New” in red Italic, right after the title)
It turned out be a site that hadn’t been updated since 2003, so I guess it’s just new to the ITT site. Anyway, the hanging system described therein bares a striking resemblance to the system I have been piecing together. So much so, that I emailed the designer out of courtesy, telling him he deserved credit for a lot good ideas that many people (including me) thought were mine. A lot of what I have come up with has evolved as this blog has progressed and my thought processes have been fairly transparent. Yet it appears I could have just gone to this guy’s site and lifted almost every idea from him. So much for original thinking. Anyway the guy’s name is Tad Winiecki and he apparently started a motorcycle gang once that Unimodal (SkyTran) founder Doug Malewicki joined. Tad thought Doug’s designs were pretty unfriendly to handicapped and elderly, (That’s for sure) so he started playing around with his own designs. Particularly intriguing is his concept for creating track from roll-formed steel. Anyway, Tad, I really didn’t steal your ideas…Honest!

Speaking of SkyTran, I have long thought that the combination of PRT and high-speed levitated travel was an odd one. Whereas the concept of going fast in podcars is nothing new, it seems to me that the “bread and butter” of PRT is in neighborhood travel. The acceleration and deceleration distances, and rounded corners of a high-speed track would seem incompatible with city layouts and traffic dynamics. Inductrack technology assumes the need for wheels at startup. I would submit that it would be best to just use those wheels for most urban use, not because wheels are better, but because the track would be so over-priced for its low-speed function. That being said, the Inductrack technology is pretty remarkable. As I understand it, in a nutshell, it involves an unpowered bed or track on which a permanent magnet studded sled will levitate as long as it is kept moving. I believe a breakthrough aspect is this; it seems that to varying degrees there exists a “magnetic friction” which is produced as repelling magnets are drawn across each other. Apparently “Inductrack” is very efficient at controlling this effect. Although Mr. Malewicki sees this invention as useful for PRT, and NASA is interested in it for launching rockets, I see another use. It seems to me that they have invented the perfect magnetic bearing. I don’t know how it would miniaturize, but for large scale or platter type configurations it would seem to be ideal. I would be interested in how it would work in wind generators for example.

Speaking of wind generators, on his Jpods website, Bill James raises the possibility of covering PRT track with solar panels to power the “podcars”. (Yes, I am trying to warm up to the term after it was pointed out to me that podcars produces better search results than PRT.) Anyway the concept of supplying energy along the track rather than “piping” it in has a certain appeal, although I would question some of Mr. James’ premises. One thing that I learned years ago is that the energy “density” of solar radiation is not all that great. Far greater is the energy density of wind, although the fact that it cubes in power every time the wind speed doubles also means the reverse – as the wind slows, the extractable energy falls off a cliff. None-the-less in windy parts of the country it’s there for the taking. Here is a picture that caught my eye recently.

The concept of having the transmission towers produce energy themselves is rather poetic, don’t you think? Part of the problem with wind generation has been that it is often not generated near where the users are. If PRT starts going between cities, the reverse will be true. The track will need power away from the city. Perfect for periodically placed wind generators.
Speaking of cubing wind energy  – One sure way to get increased wind speed is to go up. Here is a concept with nothing to do with PRT but that every PRT advocate will appreciate. Lighter-than-air wind generators. So big they increase wind speed just by forcing air to move around their shear size.


Neat eh? (photo courtesy of MAGENN Power Inc.)

Oh, yeah. Speaking of towers, I couldn’t help but notice this one, holding up this PRT track.

Who published this anyway? Beamways? Very Nice. This form of bridge is called a “cable-stayed” bridge and is quite distinct, structurally, from suspension bridges like the Golden Gate, which have cables anchored in the ground. This style is just made for PRT…er…  Podcars. It is even wind generator ready.



afransen said...

I'm not sure how suitable cable-stayed bridge piers would be for wind turbines, unless you mean vertical axis turbines. Horizontal axis turbines obviously need to face the wind, which means the turbine would have to be at least a blade's length above the cables.

I wouldn't use vertical axis wind turbines in cities. They are pretty ugly. Also, most designs need to be jump-started, requiring a motor.

Bengt Gustafsson said...

The picture is not by Beamways, but by Hans Kylberg, the maker of the Bubbles and Beams videos. He died of cancer last year. He held the idea that using fewer towers and suspension bridge technology would be a good idea. Personally I think that the height of the towers would prevent their use in many situations.

Hans made the first images of the Beamways system and also some for the FlyWay system at

Anonymous said...

Vertical axis turbines are starting to be used here (Finland) in some mobile telecom poles.

I believe this company is behind the whole idea from the 1920's. To me, these don't seem ugly at all. And they're rather quiet.

Anonymous said...

A little correction to you, Dan: :)

"So big they increase wind speed just by forcing air to move around their shear size."

Actually, the floating wind generators you have the pic of are supposed to be lifted so high up that they reach a layer of very powerful winds. Their size does not really have anything to do with that - only needed to lift them up there.... (must go!)

Dan said...

Dan The Blogger Responds –
Hi afransen, I have a tendency to throw stuff out there, even stuff I know won’t (and probably shouldn’t) stick. It’s “Dan’s 16th rule of engineering.” (post 38)
I have a tendency to alternate between very carefully considered, practical, design options and whimsical imaginings. It’s all part of the creative process, and my sense of humor. I was dreaming vertical axis, probably out in the plains somewhere, maybe circa 2050. That last sentence of that post was meant as a joke. Sort of…

Well hello, Bengt. Good to hear from you. I thought I saw a cross between the "Convenient Future" video and your site’s illustrations. That elevator technique should have been a dead giveaway to the Bubbles and Beams connection.
The question of fewer supports and suspension technology is something I want to post about soon. Those masts he shows are pretty enormous, I must say. On the other hand, Anderson’s experiences with the American cities led him to conclude that it was worth the extra expense of using round tube trusses, just to get the smallest profile and longest span. My own sense is that, in general, replacing compression components with tension components is usually a good thing. (Bucky Fuller was my childhood hero) I do, however, share your view that tall towers are a drawback. A compromise system might give the best of both worlds.

Also, that address is dead, but change “.se” to “.com” and it works. I had never explored that link very deeply, because of the great big vehicles and cartoon-like graphics. I really should have. There is a wealth of good ideas to be found. It explores a lot more technical aspects than one might think. They even promote open standards.

Thanks for that link, akauppi. I was glad to see some performance data on that style and size range. I could use something like those at my cabin. As far as the wind speed thing, although the one pictured isn’t, in reality, all that big, the laws of fluid mechanics still apply. Reasonably streamlined objects placed in a wind of a given speed will indeed increase the wind speed around them by making the wind travel further in the same amount of time. (also decreasing air pressure, by Bernoulli’s principle) With very big objects like mountains or buildings, the effect can be dramatic. Add to that the exponential increases in power from just incremental wind speed improvements, and you have an effect that I thought was worth mentioning…

Your basic point stands, though. The principle advantage of the inflatable design is to catch wind at a higher altitude. It is also true that the advantage of altitude dwarfs the fluid dynamics advantage. To those readers out there who have never considered this stuff, a main problem and expense with wind power is getting high enough to get to a stiff and steady breeze. I just get carried away sometimes with my 16th rule, and start thinking really, really big. Just wait ‘till I reveal my ultra-giant inflatable ocean-floor tethered, wind-powered, submersed-bladder hydrogen production facility!