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Darrieus Line

04/14/2011 2:22 PM

In 1979 I had a pure R&D Company, Pantech Energy System in Long Island N.Y.

It was dedicated to research in Renewable Energies. One of which was Wind.

The first thing we did in this Field was to "Invent" a Vertical Axis Wind Turbine (VAWT)

Our first idea was to use a cyclically variable vane pitch. But later experiments showed that this was not necessary. With a fixed pitch the windmill ran well, being the only problem that it is NOT SELFSTARTING.

For large machines we had to tie the vanes with wires (As in the old biplane aircraft) to fight the centrifugal forces that tended to flex the vanes outwards.

Later, we thought that it would be a good idea to flex the vanes in the factory and eliminate the guy wires.

This is how we invented our windmill. We went to patent it and found out that it had been invented in the 30's by a wonderful french inventor, M Darrieus.

The funny thing of this story is that by the same time a Canadian Company and Alcoa Aluminium Patented (Falsely) The same idea and spent enormous amounts of money in its R&D (Including Sandia National Paboratories).

Fortunately, aware ot the patent, we did not further spend a single dollar, but thought a lot about it.

Why these VAWTs have NOT succeeded in the Market?

IMO, their best advantage was at the same time their Achiles Tendon. They can accept air from any point in the Horizon, if installed verically. Now it makes a lot of sense to install them directly on the groung in a very short tower. But due to the wind sheear the layers of wind closest to the ground have very little energy.

We studied the possibilit of installing them with its axis horizontal. Later we saw the possibility of adding many of such windmills in series, making a long string between tall posts,

Then, after some rough experiments, we found out that we could liminate one blade from each individual Darrieus. The system is well balanced and only needs counterweigths at the extremes.

These long lines of half Darrieus hanging from widely spaced tall towers can be made very long, installed along mountain divides and can be used as electric transmission lines that overcompensate their own losses. The towers are much less expensive than the typical towers because, in this case they can be guyed. One important feature of the Darrieus is that it takes air from one sense or its opposite, rotating always in the same sense.

They are not orientable, but this is not so bad. In most places most of the yearly energy of the WIND comes from just one direction one sense or its opposite.

For a relatively small installation, all we need is two short lines making an angle of 90ยบ installed usually at one corner of our property.

For this machine we should balance the total yearly watt.hours against the OVERALL price and compare it with the standard wind farms of OAWTs

Generators are in the owers

Chorete

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#1

Re: Darrieus Line

04/14/2011 3:20 PM

It looks like you may need more support between towers. That looks to be 70 meters between towers. Very unstable in the wind.

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#2

Re: Darrieus Line

04/14/2011 3:44 PM

I don't believe I have seen a wind turbine blade system this wide (and low) before.

My experience in this field is mostly with standard 3-bladed turbines and wind farms, and power transmission and distribution lines, but just looking at it I think this design may have some potential practical flaws due to uneven wind loading across the blades between the two towers, and line oscillations (due to wind flow) preventing smooth movement (or even damaging the blade assembly). Additionally the design will suffer from wind direction changes reducing its overall performance (which will vary substantially between sites).

However, I have seen worse designs (from a practical point of view) proposed, tested and partially funded. Have you tried modeling the design or small scale concept testing?

If I were a wind farm operator (or in this case residential or commercial property owner) would ask how would this design compare to the equivalent of two standard wind turbines of proven design and reliability?

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#3

Re: Darrieus Line

04/14/2011 4:28 PM

Interesting idea.

I'm curious....if the patent was from the 30's and you were exploring the concept in 1979, while you might not be able to patent the idea, what stopped you from using it to create a product? Surely enough time had passed that you would not violate the patent by using the idea.

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#4

Re: Darrieus Line

04/14/2011 6:17 PM

You should not do any R&D work in a long ago expired patent, because what you may achieve is easily copied by Companies much larger with no fear of infringement.

Unless your R&D carries you to fields extremely separated from the original patent. And this has been our case, but took a lot of time.

Standard Mw propeller type turbines have seriuos problems of blade vibration, because blades are cantilevered. Also they have a problen of the need to feather the blades for hurricanes, and towers have to be standing with no guys and the machinery encasement MUST turn on top of the towe In our case blades are strongly anchored at both edges, and so no vibrations are expected, and there is no need to feather the blades because in hurricanes they stall in a natural way and the push of the wind on them gets reduced by a factor of 10. Darrieus keep turning slowly in an hurricane with no fear of damage But forming a long line of independent units there is a serious danger of torsional vibrations. So axes of each Darrieus should be a thin walled fat tube for max torsional strength. As the line of Darrieus between towers makes a flat Cathenary, the different Darrieus should be connected with strong flexible joints. I cannot empasize enough how muh simpler this DARRIEEUS LINE IS, as compared with the typical wind farmf

The GENERATORS ARE FIXED TO THE TOWERS, no need to swing them. That simplifies the electrical layout.

There is no question about the technical feasibility of this design.

The only thing to be considered is. IS IT ECONOMICALLY ADVANTAGEOUS over standard wind farms?.

Chorete

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#5
In reply to #4

Re: Darrieus Line

04/14/2011 7:02 PM

There is no question about the technical feasibility of this design.

From your point of view there may not be, but without actual modeling, small scale testing and full scale trial data I think you will find there are potential feasibility and design issues if a full-scale prototype was trialed.

The only thing to be considered is. IS IT ECONOMICALLY ADVANTAGEOUS over standard wind farms?.

Again without anything more than a picture, a brief description and my own limited personal knowledge and experience it is hard to say. I would say, possibly feasible but application specific.

Have you tried searching for similar wind turbine designs that may have been worked on or trialed either based on the patent or similar concept?

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#8
In reply to #4

Re: Darrieus Line

04/15/2011 8:05 AM

You should not do any R&D work in a long ago expired patent, because what you may achieve is easily copied by Companies much larger with no fear of infringement.

I partially disagree. If no one has generated a product based on a patented idea, that in and of itself does not mean it's not a worthwhile venture. It could be the patent was ahead of it's time (i.e. not easily implemented with existing technology at the time the patent was filed), or it could be that the patent holder lost interest or funding.

Regardless, you (or your company) could be the first to market with the product and have a leg up on the competition. Granted not as much as if your product was protected by a patent. Along those lines....during the R&D or product development it can be worthwhile to come up with a variation of the patent that is itself patentable.

I suppose it's also a matter of corporate philosophy. Years ago I worked for a company that did not want me to pursue a design as it was similar to a patented idea and the patent was still valid (or whatever you call it). Our patent attorney even agreed that the my design was sufficient in avoiding patent infringement. However, our company had recently been engaged in litigation regarding design ownership and was litigation averse, so they told me to come up with something else.

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#6

Re: Darrieus Line

04/15/2011 12:04 AM

Coming from an area (originally) where icing is a big deal in the winter, I'd think that the strength required to support those loads would be cost-prohibitive. At 25 meters, the horizontal supports and blades are right in the area where freezing fog occurs. The ice accretion rates would be truly spectacular. Those ice build-ups would be tremendously heavy. Not only would they create static loads, but also would have a high probability of causing rotational balance issues.

In general, the boundary layer varies significantly with ground cover. In the US plains, 25 meters likely does get you above most of it, but does still leave you in a zone with high gust variation. In other areas with more trees, that level would be higher up.

In general, a Darrius is less efficient than a standard horizontal axis turbine (that is why they have become the standard). Yes, it has other advantages, but the issues I point out above likely make it a problematic choice.

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#7

Re: Darrieus Line

04/15/2011 6:04 AM

Why not put up two support cables, one above the other: and have a string of vertically oriented VAWTS. That way you only lose out when the wind is directly along the line.

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#9
In reply to #7

Re: Darrieus Line

04/15/2011 8:45 AM

Hi Randall . Do you realize that you just have made one of the best inventions of the Century!.

I have seen inmediately the tremendous advantajes of your invention. There'll be no problems with cable vibrations, and the suspension cables can be used as electrical transmission lines.

Either you are a GENIUS or very lucky to have found such an amazing solution!.

In the very first answers I have already found two extremely important messages. Yours and the one about ice. The problem with ice can be solved using the energy fron the turbine to heat the differnt Darrieus It there is no wind, then we'll use stored energy.

WONDERFUL IDEA Randall. May I have permission to work on this design?.

Would you patent it? I have a very long history with patents an their serious drawbacks for independent inventors.

Do you want that I patent it in your behalf?.

Spain is one of the most advanced Countries in Wind Power

A very good place to start a serious project.

Chorete

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#10
In reply to #9

Re: Darrieus Line

04/15/2011 10:48 AM

I suspect that the patent is already blown (no pun intended) by the idea being in a public forum.

You have my permission and wholehearted good wishes to pursue the idea in any way that you want to.

EDIT

Incidentally putting the string across a valley would seen favourite: saves the cost of the towers.

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#11
In reply to #7

Re: Darrieus Line

04/15/2011 1:24 PM

Randall, as Chorete has identified this comment as "... very useful/insightful with respect to the original Forum Thread", a GA vote is in order. Well done, my genius friend!

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#12
In reply to #11

Re: Darrieus Line

04/15/2011 2:44 PM

And I, following that logic, concur with you. The OP obviously liked it. Don't know if he's voted yet, or not.

Congratulations on #100, Randall.

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#14
In reply to #12

Re: Darrieus Line

04/15/2011 7:44 PM

Thanks to both of you. The fickle nature of GAs has been discussed often on CR4, and, I have to agree that it is impossible to predict which answers will meet with others approval. But I do enjoy getting them, so 100 does seem like a bit of a milestone. You will overtake me soon Doorman, and I don't suppose either of us will ever get close to lyn.

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#13

Re: Darrieus Line

04/15/2011 3:46 PM

One of the reason why vertical axis are not popular is that with two or three blades they produce a pulsating power that translate into vibration. When more blades are added, the power is more constant but the efficiency goes down and the cost increase. Hydro-Quebec built a large one in the 1990's but had all kind of bearings problems (and others). It has been dismantled as far as I know.

The typical horizontal axis propeller offers a nearly constant torque over a full rotation. Unfortunately, you need to orient it in the wind direction.

Nothing is perfect...

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#15
In reply to #13

Re: Darrieus Line

04/15/2011 7:50 PM

I'm pretty sure I've seen pictures of VAWTs with blades which "spiral" from top to bottom: presumably this is an attempt to smooth the pulsating power?

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#16

Re: Darrieus Line

04/16/2011 8:53 AM

Exactly! This is what I did: To spiral the blades.

But aside of using them for an improved DARRIEUS I saw that it could be used to build the strangest and most beautyful flying machine

<http://www.youtube.com/watch?v=Z59qISgdRp4>

<http://www.youtube.com/watch?v=uPi-oIn5eew>

The propeller was used for convenience but it is unnecessary

Enjoy it!

<http://www.youtube.com/watch?v=e18G9x_PHI0>

I hink these videos were taken in 1979

chorete

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#17
In reply to #16

Re: Darrieus Line

04/17/2011 10:39 PM

While spiraling the blades reduce / eliminate the pulsating power problem, you still have sections of the blades that don't produce any (or much) power for some of the rotation. This means that you need more blades which increases cost and most likely decrease the efficiency.

There are good engineering reasons why 99.9% of the windmills producing meaningful power are horizontal axis propellers. The blades work for 100% of the revolution with almost constant power (if high enough from the ground).

I applaud your effort but you also must keep an open mind as why things are done this way. Good luck.

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#18
In reply to #17

Re: Darrieus Line

04/17/2011 10:49 PM

keep an open mind as why things are done this way

You have never read any of Chorete's other threads then?

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#19
In reply to #18

Re: Darrieus Line

04/18/2011 10:11 AM

Should I?

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#20

Re: Darrieus Line

04/19/2011 10:34 AM

I am really surprised at the lack of interest for my Duranopters (Choretecopters?), derived from the Darrieus during the period of time I thought to be the lone inventor.

The Duranopters are aerodynamic marvels. They fly majestatically with an enormous stability and controllability. Up to date nobody has been able to write a good explnation of its aerodynamics.

It is quite complex, but I must say :Eppur si muove! .

I wish I could find somebody in the list who wants to build one with electric motors and RC. It is worth the time consumed.

chorete

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#21
In reply to #20

Re: Darrieus Line

04/19/2011 10:45 AM

Chorete, I admit I have never heard the word 'Duranopter' before today. Wikipedia knows it not, and a Google search of the word turns up three YouTube videos, all posted by you.

Other than an intriguing and interesting small scale demonstration, what would be the utility of such a flying machine?

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#24
In reply to #20

Re: Darrieus Line

04/19/2011 10:38 PM

very interesting! ... where else did you mention these?

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#25
In reply to #24

Re: Darrieus Line

04/20/2011 6:26 AM

At post #16 above

Chorete,

.....Yes I agree (GA for post #16), very interesting. Do you have any build plans? Or plans to make and sell them?

As an aside Chorete,

......In order to keep the "conversation flow" readable: when you reply to a specific post use the reply button just beneath the post:-

The advantage of this may not be obvious if your default setup is to read posts chronologically.

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#26
In reply to #25

Re: Darrieus Line

04/20/2011 8:25 AM

well that is why I didn't see it before.... not properly linked.

and who has time to cut and paste... lol

dear Chorete... when making a link, just right click on a selected word, and paste the link and click okay.

thanks Randall

Chris

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#22

Re: Darrieus Line

04/19/2011 4:59 PM

Practically nothing.

But they are a beautyful excercise on Aerodynamics.

They are so intrinsically stable (Not due to gyroscopic forces, the stablity is aerodynamic, with NO control surfaces) that may be they could be used as UAVs by the Military or some other nasty use.

Sorry

Chorete

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#23
In reply to #22

Re: Darrieus Line

04/19/2011 5:07 PM

"But they are a beautyful excercise on Aerodynamics."

I agree 100% I have watched your videos, and I am considering building one (attempting, anyway), just for the fun of watching it fly.

Thank you Chorete!

[edit] As I consider, have YOU considered offering these in a kit form? Can this be protected with a patent (I sort of doubt it)? This might be the next Hula-Hoop. Go ahead, make a little money from this. While this is not a great contribution to the betterment of mankind, was the Hula-Hoop that contribution?

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#27

Re: Darrieus Line

04/20/2011 12:26 PM

About the Duranopter (Duran is my Last Name), I am glad that most people likes it.

In 1979 I demonstrated it in front of several friends, engineers from Grumman, Republic Aviation, Boeing and Piasecky. Let me say without false humility, that they were all astonished. There was a very hot discussion to find out what was the use for it.

And the conclussion was that the best bet was to make a toy. I felt offended and left it in a shelf ll these years. But I have changed my mind and now I really would like that some of you takes seriously the idea (That could be millionaire) and starts making toys. Either rubber prowered or electric RC.

As you may understnd I have a lot of knowledge on the subject.

So I warn any possible volounteer to be aware of the difficulties.

The major problem is that nobody has been able to describe its aerodynamics, so it is not possible to follow a reasonable path to improve it. Everything must be matter of trial and error.

It is surprising how things that you are sure would improve the flight, do not work at all.

Nevertheless I promise all my help. I have lots of CADs and real protos .

chorete

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#28

Re: Darrieus Line

04/21/2011 4:34 PM

I still would like to lure somebody into building one of these flying beauties.

http://www.youtube.com/watch?v=4qQo98bm-Dc

Chorete

I am a computermoron, can't create the link

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#29
In reply to #28

Re: Darrieus Line

04/21/2011 4:41 PM

WOW! I did it.

Chorete

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