Adriaan, here is a better explanation:
On your report, KD 599, you have this link:
www.greenenergywindturbine.com/download/vawt/760131.pdfThat link doesn't work because that website (greenenergywindturbine.com) is OUT-OF-BUSINESS and FOR-SALE.
So I did a search and found the PDF that you were linking to. That PDF deals with the testing of TWO and Three-Bucket Savonius Rotors by Sandia Laboratories. I provided the new link to where I found the PDF, which is this:
www.vawt.om2cm.sk/sites/default/files/2or3savonius.pdfMaybe you want to update your KD 599 report and add the link to where the PDF is still available.
I hope this is clear.
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By the way, this is an interesting thread. I would like to encourage Elemental Madness and topspeed to continue with their experiments. With the guidance of ULR, electrondady1, Adriaan and others, it could be possible to come up with a practical VAWT design that is easy to build.
As I said before, a HAWT mounted on a high tower would be ideal to produce power from the wind. Not everybody has the land or the money to pay for and erect a tall tower. There are millions of people around the world that have strong surface winds and would like to be able to make a little power, and for them, a VAWT would be ideal.
What choices do we have? There is the Darrieus, patented by Georges Jean Marie Darrieus, a French engineer, in 1926. And the Savonius, invented by the Finnish engineer Sigurd Johannes Savonius in 1922 and patented in 1925.
The Darrieus needs fast winds to start turning and then they spin so fast that end up self-destroying. The Savonius turns too slow to produce any power with the home made axial flux alternators that we build today.
We need to combine the H-Darrieus and the Savonius into one design that would start in low winds and would not go so fast that it blows to pieces.
We don't have to depend on designs that are over 90 years old. We can learn from them, but this is 2019 for crying out loud!!!
It is time to re-invent the wheel. We can do it RIGHT HERE, RIGHT NOW.
If you are a guest reading this, I encourage you to join the Forum and help us design a VAWT for the 21st century.
Here is a design that I have been working on for a long time. I am presenting it here for your consideration and critique. I hope that we can improve it and someone can build a prototype for testing. I call it the Darivonius 2020.
Ed