Fieldlines.com: The Otherpower discussion board
Homebrewed Electricity => Wind => Topic started by: Rudl on May 09, 2011, 04:37:19 AM
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Hi all together,
I want to make a Savonius Rahai construction,
I have found here: http://www.energy.ca.gov/2005publications/CEC-500-2005-084/CEC-500-2005-084.PDF on page 19 the optimized form.
I draw it over and did it in the picture of page 22 to find out the centre of rotation. There I notized, that the curve which I draw over on page 19 is not as high as the curve on page 22.
Can someone tell me, which is the better solution.
Rudl[attachment=1]
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Maybe the picture has just been stretched for design issues?
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That design was discussed here more than a few times.
The profile outlined in red is considered the optimum profile though I don't know of anyone whose built a machine using that profile.
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This profile seems not to be very popular.
Is there a reason?
RUdl
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RUdl
That was an interesting read, however a few things come to mind after reading that and doing a little more searching and then re-reading.
The non-popularity may come from the need to engineer fabrication methods and then building an actual device.
When this "study" was doned there was more modeling done using computational methods than real work-horse type testing.
If you take a look at the wing style and the fact that there may be the need for specific overlap or gap or a combination of both , this design may not be in the realm of most DIY'ers.
While this style does seem to have benefits over the larger wind speeds even the speed they have are far higher than a great number of DIY mills are built for.
IF you setout the build a unit with this profil, I for one would like to see the 3-D mock-up and subsequent testing in winds ranging from 6mph and above.
Bruce S
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The upwind side of the of the cycle is the problem . For the most part the drag side can't get any faster than the wind speed regardless of how well you do getting the upwind foil worked out . One thing this design has going for it is the a short upwind cycle and the wind jet from one blade to the other . I haven't built one of these . I do think they have good torque built tall . The genset needs to remain set to cut in at after the RPM is up .