[Turtle]

I have in mind to try building a small windmill for electrical generation, and the simplest rotor looks like the Savonius rotor. The biggest drawback is the air resistance of the backsides of the cups, and I already have some design modifications in mind to offset this.

Here's a bit of a read-up on rotors and the power of wind in general. Practical Wind Generated Electricity
Interestingly, the Wicki article on Savonius rotors is auf Deutsch und meine wortsprache sind klein. Plenty of reading out there if you just search 'Savonius rotor'.

Any of you have any practical experience with this design? Any of you have any impractical experience with this design? I'll be back in a while with some little drawerings.

PS Found a wicki auf Englishe >>Savonius wind turbine - Wikipedia, the free encyclopedia

auf Deutsch >>Savonius-Rotor - Wikipedia

[Jay-qu]

How does the air that gets in their efficiently escape?

[Turtle]

Originally Posted by Jay-qu

How does the air that gets in their efficiently escape?

I think it spills out the out-board edge as the rotor turns. I have a little one made of a pop can, a couple straws, and corrugated paper; however, we have no wind just now and my little fan is insufficient to turn it.

I saw one article in which the writer suggested using fabric rather than solid material; I like that idea.

This little bit is what I have in mind more or less. >> IngentaConnect Valve-Aided Twisted Savonius Rotor

Originally Posted by ingentaconnect.com

...Another proposition for increasing specific output is to place non-return valves inside the concave side of the blades....

I'm thinking vanes on axles like a shutter to act as the valves; when the convex side is facing the wind the shutters close and full force is applied, and when the convex side comes into the wind the shutters open and let the air through. Admittedly more moving parts, and I can only imagine what it would sound like operating, but it might overcome the main inefficiency of the Savonius rotor.

We'll see how jazzed I get when I get some wind (without rain) & try my little model. I'll put up a vid on u-tube of it.

[freeztar]

Originally Posted by Turtle

I think it spills out the out-board edge as the rotor turns. I have a little one made of a pop can, a couple straws, and corrugated paper; however, we have no wind just now and my little fan is insufficient to turn it.

Take it to the Columbia!

I saw one article in which the writer suggested using fabric rather than solid material; I like that idea.

Don Quixote Style!

I'm thinking vanes on axles like a shutter to act as the valves; when the convex side is facing the wind the shutters close and full force is applied, and when the convex side comes into the wind the shutters open and let the air through. Admittedly more moving parts, and I can only imagine what it would sound like operating, but it might overcome the main inefficiency of the Savonius rotor.

What if the "shutters" could be angled in such a way to create lift as well as provide for the system you suggest. The vertical motion could be converted into lateral motion, thus accelerating the axle even more (retention of efficiency, maybe?).
I'm envisioning something similar to those toys in which you spin the stick and the toy fans out and floats/accelerates up (they look like umbrellas, can't remember the name).
Or perhaps more to the topic, aerodynamic ridges within the semi-cylinders that correlate with helicopter blades, or perhaps a different 'lateral lift' approach.

Or perhaps I'm bonkers...
I love brainstorming though.

Come to think of it, perhaps a Mobius strip holds the answer.
This makes me think of the correlation that was drawn between Mr. Fuller and the phenomena observed on the north pole of Saturn. Perhaps convex and concave are not the best.

[Turtle]

Originally Posted by freeztar

Take it to the Columbia!


Don Quixote Style!



What if the "shutters" could be angled in such a way to create lift as well as provide for the system you suggest. The vertical motion could be converted into lateral motion, thus accelerating the axle even more (retention of efficiency, maybe?).
I'm envisioning something similar to those toys in which you spin the stick and the toy fans out and floats/accelerates up (they look like umbrellas, can't remember the name).
Or perhaps more to the topic, aerodynamic ridges within the semi-cylinders that correlate with helicopter blades, or perhaps a different 'lateral lift' approach.

Or perhaps I'm bonkers...
I love brainstorming though.

Come to think of it, perhaps a Mobius strip holds the answer.
This makes me think of the correlation that was drawn between Mr. Fuller and the phenomena observed on the north pole of Saturn. Perhaps convex and concave are not the best.

Try as I might, I can't edit one iota of your post to quote.

I tried the Mobius strip, but it acts as a wind vane (with an axle down the long axis) rather than a rotor. That is to say it rotates 'into' the wind and stays there until wind direction changes. Great minds think alike though.

Here's a little vid of my pop-can getup. The spinning is by hand just to show rotation. Wind tests to follow, weather permitting. >>

YouTube - savonius rotor

I thought about giving the vanes/shutters and airfoil cross-section too, but for now expect any model I make to be a down-n'-dirty version.

By all means please submit drawings and or models of your own design ideas. One source I read said this is the oldest type of windmill on Earth, which makes improving it practically, something of a unique challenge.

[Turtle]

Originally Posted by Turtle

...
I thought about giving the vanes/shutters and airfoil cross-section too, but for now expect any model I make to be a down-n'-dirty version.

By all means please submit drawings and or models of your own design ideas. One source I read said this is the oldest type of windmill on Earth, which makes improving it practically, something of a unique challenge.

Sweet Mother of Betty!! Can I make an understatemnt or what!? When I think 'proof of concept' or 'model' I never would have imagined this!!! >>

YouTube - Encore Clean Energy SideWinder Wind...

That is apparently just the beginning of videos of Savonius rotors gone wild. Oh lordy!

addendum (ok;more dum'b than adden' )

YouTube - Neo-Aerodynamic 1 at low wind Wind...

YouTube - 50lb Savonius Wind Turbine

[Jay-qu]

Hey check this one out! I dont know if it counts as savonius, but its cool

YouTube - Aerotecture Wind Turbine

it looks like they tapered the ends, maybe that helps with the air getting out..

[InfiniteNow]

Originally Posted by Jay-qu

Hey check this one out! I dont know if it counts as savonius, but its cool

YouTube - Aerotecture Wind Turbine

it looks like they tapered the ends, maybe that helps with the air getting out..

Getting the air out has never been a problem in this household.

Per Jay's suggestion, here is another link with more:

Aerotecture International - Products

[Turtle]

Originally Posted by InfiniteNow

Getting the air out has never been a problem in this household.

Per Jay's suggestion, here is another link with more:

Aerotecture International - Products

I saw the vid when I was surfin'; thanks for the link too. My only qualifying remark is that it's not a Savonius rotor as it uses airfoils.

I'm starting to think about how to incorporate a laminar flow housing to collect wind over a larger surface area (intake duct) and deliver it to the Savonius rotor at a higher pressure and lower surface area (cross-section of delivery duct.) We'll see.

[CraigD]

If it was my effort going into the project, I’d make a Darrieus wind turbine. It has a simplicity and vertical orientation similar to the Savonius, but is much more efficient – better, ultimately, than a traditional propeller windmill design. There are quite a few interesting variations of the design, including modifications to get around the design’s chief limitation of not being self starting.