Talk:Savonius wind turbine

Error in power formula?
My job is wind turbine engineer (horizontal axis), and normally the power is P = .5*C_P*rho*A*v^3

I don't think that's different for a Savonius turbine. However, if I calculate the C_P that the .36 from the text gives, assuming 1.225 kg/m air density, I get C_P = .36/(1.225*0.5) = 0.59, the Betz limit. I guess someone thought that the Betz limit, which is a theoretical maximum for _all_ turbines, is also the maximum for the Savonius? That's untrue, because it's efficiency it much lower that a horizontal shaft type. From here http://re.buildingefficiency.info/wp-content/uploads/2012/08/turbine_efficiency1.jpg I get a C_P of max 0.15, almost four times lower. I think someone should adjust the formula or many get disappointed :( — Preceding unsigned comment added by 80.61.120.187 (talk) 16:13, 20 June 2014 (UTC)

The above link to a jpeg (an absence of any citation) doesn't work, so there is no validation of the assertion of lower efficiency.

Also in the power formula discussions in the main article, the assertion that the Savonius is a purely drag device is questionable, for two reasons;

1) any wind current, on striking a vane and exiting, is directed onto the rear of opposite advancing vane, applying some degree of force. 2) there is the potential for some degree of lift being generated by the curved edge of the vane as it advances into the wind current. Donquixote2u (talk) 02:33, 24 June 2018 (UTC)

Adjusting the tilt of the blades
has anyone tried adjusting the tilt of the blades as speed increases? — Preceding unsigned comment added by 144.138.113.88 (talk) 07:57, 25 August 2005 (UTC)


 * There is no merit in doing so with the Savonius because it relies totally on the differential drag between the two halves. Tilting the blades doesn't really affect drag significantly. Perhaps you'tre thinking of the Darrieus wind turbine which has aerofoil-shaped blades and relies on lift rather than drag. In such a turbine, tilting the blades cyclically can give worthwhile improvements, and has been tried on a small scale. Unfortunately the Darrieus doesn't scale up all that well, not because of the aerodynamics but because of simple centrifugal and cyclic lift forces, which require substantial mechanical structure to withstand - adding cyclic pitch control into the mix would make for a complex and problematic structural design. However, since helicopters have even more complex blade control and they seem to work, the problems are probably solvable, but the current view seems to be that Darrieus type designs are not worth pursuing when the more conventional propellor type is a more understood and mature technology, and which overall gives better results in theory and practice. Graham 23:23, 25 August 2005 (UTC)

Link trouble
The first link (about DIY wind turbine) does not work --Jean Yevenes (talk) 18:20, 3 August 2008 (UTC)

Commercial link
Link about helixWind turbines should not be there, it's commercial. —Preceding unsigned comment added by 86.66.32.161 (talk) 10:25, 20 November 2010 (UTC)

Diagram and dimensions
There is no explaination of D and E dimensions in the third image. Biggerbyfar (talk) 11:20, 12 July 2009 (UTC)

Move

 * Not Moved. A redirect has been created. Station1 (talk) 05:38, 2 October 2009 (UTC)

Savonius wind turbine → Savonius WECS — I propose to move the article to the name Savonius WECS to allow the article to be used to explain mechanical devices that used the Savonius bladed rotor. See wind energy conversion system (WECS) KVDP (talk) 14:15, 24 September 2009 (UTC)
 * Oppose but by all means add the info that you wanted to add. It doesn't sound like you need to change the name of the article to do that. 199.125.109.138 (talk) 17:18, 24 September 2009 (UTC)
 * Oppose Savonius wind turbine is a perfectly good title - Savonius (name of inventor) wind turbine (what it is). See also WP:COMMONNAME. Mjroots (talk) 10:48, 25 September 2009 (UTC)
 * Oppose Current title is descriptive of the article, proposed title is cryptic. A redirect would be appropriate though.   GB fan  talk 13:13, 28 September 2009 (UTC)

Origin Johann Bessler
Since there is no citation of evidence, Johann Bessler should not be mentioned as possible inventor of the original savonius-rotor in this article. In the finnish Biography from Sigurd Savonius is written, that Savonius has been trying to find a way to make Flettners Rotor independent of any artificial Powersupply to serve for it´s inicial Spinspeed of 4 times the Windspeed. As result he found his remarkable simple and in terms of aerodynamics at the same time higly complicated technique. It is not very logico, why Bessler should have had such avanced knowlegde about aerodynamics. Sigurd Savonius, so tells his autobiography, spent Years on the finnish lakes with a small rowing boat trying and testing his invention as a propulsion for ships. He died quiet young of lunginfection, results from this particular investication are - to me - not known.

And anyways, You can be shure, in germany Bessler would be named as Inventor for this concept if there was just a little a chance to it. Bessler is not mentioned anywhere concerning Savonius. There is nothing to be found. To me it seems to be just a bad joke. --Kalinco (talk) 08:00, 16 August 2011 (UTC)

More than a month ago I asked about the Bessler Question here, but no reply. I surched german literatur for Bessler as early inventor of the savonius turbine type. To mention Bessler is nonsens. Proof: Autor Felix von König in his book "Windenergie in praktischer Nutzung" 2. Edition 1978, Udo Pfriemer Verlag, München -ISBN 3-7906-0077-6. He describes a very rich range of historic Windmills in all kinds of application an technique from VAWT to HAWT up to modern times. He mentions the savonius-Rotor as invention made by Sigurd Savonius, Finnland. He also describes ancient Windmills with curves Blades but not the special technique from Savonius, dating from the 17.th century, describedin the book from 1616: "Machinae novae" written by Fausto Veranzio, Italy. There is absolutely no mention of Bessler found Königs book and neither in any other cientific volume to be relied on as proof, that he could have had any relation to Savonius invention. I am going to rectify this part in Your article. --Kalinco (talk) 06:23, 2 October 2011 (UTC)

The gap is not mentioned.
Upon gap zero between buckets, there is firm prior invention in the Butler Ames patent. Ames had zero gap for a rotatable airfoil. The US Navy bounded a study of Savonius at gap 0.0. But at gap 0.0, Butler Ames would be the inventor in a filing in 1908. 68.123.235.180 (talk) 20:31, 12 December 2014 (UTC)

Iceland
A company from Iceland has a diffferent design. Setenzatsu.2 (talk) 21:46, 21 April 2020 (UTC)