Flying Wind Turbines

OneWayTraffic · Post by **OneWayTraffic** » Mon Jun 23, 2008 6:11 am

www.skywindpower.com

Basically the idea is to put a rotorcraft at the end of a kilometers long tether and fly it into the jetstream. Once there the electric motors switch into generators and generate power for both lift and electricity. There's a peer reviewed paper with specifics. "Harnessing High-Atitude Wind Power" with the IEEE. I've read the paper and apart from personal increduity at the whole idea it actually sounds well thought out.

Any of the engineers and physicists on here want to have a look and critique? If it works this could be as big as polywell for terrestial use.

MSimon · Post by **MSimon** » Mon Jun 23, 2008 9:09 am

I think this has already been shot down here.

BTW how do you get the cable untangled?

How do you handle wind shear?

Tom Ligon · Post by **Tom Ligon** » Mon Jun 23, 2008 12:07 pm

Sounds like a fun kite toy to me.

I think it can be made to fly and produce power, but I doubt it would be as worthwhile as supporters think. Existing wind farms are amazingly feeble for their sizes. Enough of these to make a dent would amount to a huge number of cables for planes to weave thru.

OneWayTraffic · Post by **OneWayTraffic** » Mon Jun 23, 2008 1:24 pm

MSimon wrote:I think this has already been shot down here.

BTW how do you get the cable untangled?

How do you handle wind shear?

I don't recall any thread on it. I'll have a search but if you could give a link...
Why would the cable get tangled? I understand they'll use a combination of GPS and modern avionics to maintain position. This should also help vs wind shear. The kites themselves will be capable of powered flight so that could be used in a pinch. Here's a 30second clip taken way back in the 80's of a very early prototype.

http://nz.youtube.com/watch?v=QndvFtdPfcM

The guy who first had the idea was a professor of engineering so I'd guess that he's thought of the obvious problems. I'm sure they'd lose a few to accidents every year but the energy payback is very good so a mean lifetime of just a few years wouldn't be an issue.

Has anyone read the peer reviewed article?

OneWayTraffic · Post by **OneWayTraffic** » Mon Jun 23, 2008 1:36 pm

Tom Ligon wrote:Sounds like a fun kite toy to me.

I think it can be made to fly and produce power, but I doubt it would be as worthwhile as supporters think. Existing wind farms are amazingly feeble for their sizes. Enough of these to make a dent would amount to a huge number of cables for planes to weave thru.

They'd plan to restrict the airspace.

A FEG is a tethered device, and tethers going up to high altitudes obviously pose a problem to aircraft. But, while it is not well known, balloons tethered at up to 15,000 feet already exist along the southern border of the United States carrying radar equipment to detect drug flights.

Calculations show that airspace restricted for power generation will need far less restricted airspace to supply all the nation's needs than is already restricted from civil aviation use.

From the site there's plenty of places in the jetstream where wind produces in excess of 5kw per square meter and up to 20kw. Efficiency of turbines is about 50%. Putting a unit with 1000sq m of swept area in here could capture about 0.5*1000*5kw=2.5MW of energy with considerably higher than 50% capacity factors. Then it's all a question of how big you can make them (they think 10MW is optimum) and how many you can stack in a certain area (a balance of energy density vs risk of collisions.)

I'm not saying it's easy. But I wouldn't say that it's harder than fusion for example. Rather the opposite it seems to me. And this is just one method for capturing high altitude wind. There's a bunch of others and only one needs to work well.

OneWayTraffic · Post by **OneWayTraffic** » Mon Jun 23, 2008 1:38 pm

MSimon wrote:I think this has already been shot down here.

BTW how do you get the cable untangled?

How do you handle wind shear?

We get many questions about weight and electrical losses in the tether, and other aspects. Tether technology is not simple, but a number of vendors now compete in this field selling primarily to the military and NASA. There are now available commercial tethers meeting our specifications, which do not weigh too much, have relatively small electrical losses, and meet other requirements. Transmission is at high voltage, which means that small diameter, light, conductors may be used. The electrical losses which do occur, while not sought, do result in warming the tether, which is desirable.

Lightning and atmospheric static discharge as they affect tethers containing conductors are problems frequently brought to our attention. The name of Benjamin Franklin is often mentioned. However, the frequency of conditions in which these atmopheric conditions are a potential problem is close to zero in key parts of the world needing energy the most. This includes much of the United States, as may be seen by clicking on this NOAA link to view Vaidala's NLDN 5 year Flash Density Map: http://www.lightningsafety.noaa.gov/lightningmap.htm.
Even where lightning conditions do seasonally exist, with good warning provided by current technology, FEGs will be grounded, and returned to service rapidly after the passing storm. Furthermore, lightning problems have been addressed and solved in other tether applications and will be utilized by FEGs when conditions are not severe.

When encountered, turbulence is a problem for FEGs, but a tethered rotorcraft such as an FEG has the freedom to move a little, like a kite, and settle back, rather than sit rigidly restrained by a tower and vibrate. This comes about primarily because of the long tether simply changing shape a bit when the FEG encounters a wind gust and then gradually resuming its natural drape, thus reducing tensions at the FEG. This is typically by over a factor of ten as compared to being rigidly restrained.
In addition, programmed electronic controls, using GPS and gyroscope attitude sensing information, assure that rotor pitch and airfoil control surfaces react in damping fashion to the FEG movement in this situation.

That last paragraph sounds like it's been thought out to me.

Mike Holmes · Post by **Mike Holmes** » Mon Jun 23, 2008 1:46 pm

If somebody questions polywell containment, they just need to be convinced. If it's a flying wind station, then cables and windshear make it impractical...

I see...

I suppose you can always claim that you're doing the other guy a service by making him constantly explain himself. Not just buying into the pat explanations given on the website. Uh... casual peer review? Healthy skepticism should be a part of any scientist's mind, I suppose. But so is enthusiasm for discovering new processes... no?

Wind shear? Isn't that just one of those "engineering details?" That's the explanation that's always given for those minor nuisance problems that are involved in creating a IEC reactor that would be used to produce power.

I can hear somebody saying "If it can be proven to provide excess power, platoons of engineers will be put on the project to solve all of these little problems." That's what we'd say about polywell, no?

To be clear, I'm not a fan of polywell, specifically... I'm a fan of whichever technology gives us cheap green power that gets us off of depenence on foriegn oil markets. Jupiter can wait until we get world peace.

Let's say instead of tethers, they manage to figure out how to generate power in the flying stations (small generators run on excess prop turbine speed or something). The power could be fired back to earth by laser. Since the devices are maneuverable, in theory, they can even avoid cloud-cover, especially if there are multiple ground stations to fire at (which there'd have to be).

Who knows what they might come up with?

Are all energy projects really a competition for funds and mental capital? (I wouldn't presume any intellectual jealousy as the source of any objections, but you gotta know it's going to look that way to the non-converted).

Ever seen the BBC series called "Connections" by James Burke? No? Rent it ASAP (your library probably has a copy).

It'll be some guy coming up with a solution to flying his "kite" that ends up making fusion power possible. Or something equally as unpredictable. Even if he never produces a watt of usable energy.

Mike

OneWayTraffic · Post by **OneWayTraffic** » Mon Jun 23, 2008 1:56 pm

Mike Holmes wrote:If somebody questions polywell containment, they just need to be convinced. If it's a flying wind station, then cables and windshear make it impractical...

I see...

I suppose you can always claim that you're doing the other guy a service by making him constantly explain himself. Not just buying into the pat explanations given on the website. Uh... casual peer review?

Wind shear? Isn't that just one of those "engineering details?" That's the explanation that's always given for those minor nuisance problems that are involved in creating a IEC reactor that would be used to produce power.

I can hear somebody saying "If it can be proven to provide excess power, platoons of engineers will be put on the project to solve all of these little problems." That's what we'd say about polywell, no?

To be clear, I'm not a fan of polywell, specifically... I'm a fan of whichever technology gives us cheap green power that gets us off of depenence on foriegn oil markets. Jupiter can wait until we get world peace.

Let's say instead of tethers, they manage to figure out how to generate power in the flying stations (small generators run on excess prop turbine speed or something). The power could be fired back to earth by laser. Since the devices are maneuverable, in theory, they can even avoid cloud-cover, especially if there are multiple ground stations to fire at (which there'd have to be).

Who knows what they might come up with?

Are all energy projects really a competition for funds and mental capital?

Ever seen the BBC series called "Connections" by James Burke? No? Rent it ASAP (your library probably has a copy).

It'll be some guy coming up with a solution to flying his "kite" that ends up making fusion power possible. Or something equally as unpredictable. Even if he never produces a watt of usable energy.

Mike

I like your first paragraph especially.

But the tethers are an integral part of the design unfortunately. Without the tether, then the turbine would need to expend more energy to stay on station than it could possibly generate. On the other hand "commerically available tethers exist that satisfy our specifications." I'd love to be able to say the same about polywell design.

Mike Holmes · Post by **Mike Holmes** » Mon Jun 23, 2008 2:15 pm

Yeah, my laser idea is purely speculative. But the point is that it's this is the kind of project that can fuel imaginations, and the end result may be something unforseen. Compare the first fission reactors with what folks have come up with more recently as the plans for new reactors. You can't imagine the latter plans without the original, inefficient, reactors having been designed.

The Wright Brother's flyer wasn't practical at all. But the airbus is. You can't get the latter without first getting the former.

One of my favorite quotes is from one of the Wright brothers (I paraphrase as it's from memory), "I don't believe that man will ever achieve powered flight." A statement made just a few years before he proved himself wrong.

At the very least, when being skeptical of somebody else's project, use that perspective to see how the majority of people are going to see the Polywell project. Yeah, probably a lot less "proven" than the wind-power idea in question.

Mike

Tom Ligon · Post by **Tom Ligon** » Mon Jun 23, 2008 2:28 pm

You should see some of the nutty flying machines I work with. There's nothing about this thing that won't fly given a stiff breeze. Its a tethered autogyro, simple.

The pilot in me is worried about restricting airspace, and how much airspace. There's a heliostat flying near Yuma at about 15000 ft (I've flown over it and seen it). Check the airspace restriction circle around it. Now calculate how much of a circle, or maybe an arc, since the prevailing winds at altitude will be more or less westerly, you need for something flying in a jet stream. How much power does it make? How many do we need? How much airspace must be restricted? I think there's gonna be an awful lot of restricted airspace if they rely on this technology.

And the jet stream moves.

All alternative energy production schemes will go into the pot and we'll see what cooks up. If the Polywell works as well as Dr. Bussard thought, it will be very strong due to high power output for the capital equipment, and good, steady output in all weather, 24/7. That will knock out most competitors, not because they won't work, but because they won't compete.

But, alas, the Polywell has a way to go. I have no objection to looking at all the options, and this is one of them. I'm just not excited by the prospect of all those cables in my airspace, if we can avoid it, particularly if the output fails to allow me to live in the manner to which I am accustomed.

And if it flys, my present company will probably be controlling it, which I have absolutely no doubt we can do.

hanelyp · Post by **hanelyp** » Mon Jun 23, 2008 6:22 pm

I have high confidence something like this could be made to work. Ideal altitude and turbine configuration remain to be determined. Cost for the system is uncertain until someone pulls it off.

If this turns out to be a winner, expect the watermelons to scream bloody murder over disrupting the jet stream and messing up weather patterns.

Mike Holmes · Post by **Mike Holmes** » Mon Jun 23, 2008 6:25 pm

LHM?

I like Polywell, specifically, for the reasons you state, Tom. Yeah, if I had my druthers, fusion reactors sounds way more fun and profitable than tethered wind machines. Jupiter (heck, Alpha Centauri, if we implement Bussard's other big idea) would be a wonderful side-effect.

But I'll take what I can get. A bird in the hand...

My point is simply that I'd rather not knock a new technology without it being demonstrated as being a problem. "It might limit my airspace" sounds about as good an objection as "politicians might shoot it down because you could put it on a pair of semis, and use it to irradiate downtown Manhattan." (A fear that one poster had of the polywell).

Which is the weirder idea... thousands of mile-long cables... or ten-million degrees in an electromagnetic bottle?

I think that the carbon-sequestering, fuel spewing, bio-bug might be the weirdest idea. And maybe the best...

But the one that lowers my commuting bill soonest (without destroying the environment*) is the one that's the best. Sorry if that's greedy.

Mike

*I've always been intrigued by the "explode thermonuclear weapons in a cave" idea for a fusion reactor... but not crazy enough to advocate it.

MSimon · Post by **MSimon** » Mon Jun 23, 2008 8:33 pm

When it comes to BFRs, I believe I have pointed out every flaw I have seen. With the idea: "if we know the problems we can work on solutions".

Some one in a recent thread said I shouldn't be so out front about the proliferation problems of BFRs. My reply was: yes I should.

All this should be taken in the spirit of a rigorous design review. All designs should be rigorously reviewed.

MSimon · Post by **MSimon** » Mon Jun 23, 2008 9:00 pm

I believe barrage balloons were used extensively in WW2.

the real objective of the balloons was to deny low-altitude flight to the enemy.

http://wiki.answers.com/Q/What_were_Bar ... ir_purpose

So might we conclude that the purpose of these power tethers is to deny high and low level flight to our friends?

After you make them work economically you have to figure out how to integrate them into the air travel system. BFRs only have to be made to work with and integrate with the current electrical power system.

And don't aircraft use the jet stream to lower fuel costs?

Some things will need to be worked out.

Mike Holmes · Post by **Mike Holmes** » Mon Jun 23, 2008 9:10 pm

Rigor, absolutely. And you should expect the same from our flying generator friend. Good work.

I'm not seeing a lack of rigor on either side.

On the other hand, your proposal that the purpose of their design is to forestall flight, because that was what air barage balloons were for, is akin to saying that the purpose of cars is to kill us, since they give off emmisions that were used in Nazi death camp experiments. A bit of a lack of rigor there.

I'm not saying it can't be a problem, or won't. I'm saying that they'll try to avoid it, cognizant of the problem as they are, and we won't know until they show us the design.

Mike