New C Rotor with free flooting C

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New C Rotor with free flooting C

Beitragvon BobMann » Di 6. Dez 2011, 02:38

Hello from the USA Now I can read your post. I am the builder of the Tree Top Wind Mill a VAWT using a Lenz and a Mann Smart Drive I invented.
I build a copy of the Lenz to work with my PMAs. I have found them costly to build. I designed a C rotor that has a piviteding C tube to help with wind drag.
I would like some feed back on it if you would be so kind. I very much like the work you have been doing over there with it.
I have done some wind drag test of the Lenz to the C Rotor blade and a VID to show the come of the redeisgn of the C. i still need some feed back on what PMAs
you have been running with this blade and blade count.
Here is my Youtube

http://www.youtube.com/user/CNGBOB?feature=mhee

Bob Mann
Boston MA USA
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Re: New C Rotor with free flooting C

Beitragvon Bernd » Di 6. Dez 2011, 18:23

Hello Bob and welcome to this board.
I know your windturbines and your experiments from the vawts.net site.

I am happy to see that you now are interessted in the C-Rotor.
I have seen your video were you have repelled the turbines using an electrical motor.
I like the way you find your conclusions, especially this comparement i think is interesting and helpfull.

Do i think right that the "half fasten" mounting of the the C slat is not self adjusting when spinning ?

What i can say so far is that our formulas, how to find the dimensions of the C-Rotor blades, are calculating
a bit to small blades. Until now i think around 30% bigger than our formulas are calculating, we will be much
closer to the ideal blade dimension.

Grüsse

Bernd
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Re: New C Rotor with free flooting C

Beitragvon BobMann » Di 6. Dez 2011, 18:56

Hello
I am build it with a 4 inch half C tube now for testing with a 3 blade at 30 inch circle.
I fell the plate needs to be used in the push part of the unit like in the flat side of the Lenz 7%.

I have over come the C getting stuck in a closed postion at stand still in vawt.net site some one posted this. I will use
three magnets to per blade to hold them in the stock location and limit the C from closing right up with a rubber stopper.

I will re run the test VID for you with unit before installing on my tree test site.
You have done some great work here.
My wife is German
You group should take a close look at my Mann Smart Drive as a low cost but supper strong PMA.
Bob Mann
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Re: New C Rotor with free flooting C

Beitragvon Bernd » Di 6. Dez 2011, 19:07

Oh if your wife is german, you must be able to speak german too. :)
Some time ago i did some measurements using a AOA at the C-Rotor blade, but i ever got the best results
at 0 Degree AOA. Maybe you will find out something different.
I have 4 Fisher Paykel smart drives in my garage, but not finished until now.

Grüsse

Bernd
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Re: New C Rotor with free flooting C

Beitragvon labitrail » Mi 7. Dez 2011, 11:28

An interesting idea to let the C float freely depending on the direction of the air stream. I was thinking about to position the C not in the middle of the blade but in a ratio around 1/3 to 2/3 (inner / outer distance) to use the main air stream to push it forward like the Lenz but also to use the stream flowing back on the inner side for buoyancy. Perhaps this may also work in combination with the floating C.
Bodo
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Re: New C Rotor with free flooting C

Beitragvon BobMann » Mi 7. Dez 2011, 14:14

I had that in mind when testing the floating C .
I have a test set of 3 wings build using drain 4 inch PCV thin wall pipe. it would be very easy to drill a few set of mounting hole off center to do your test.
I have tested the magnet stop for the outside C to plate worked great. So in at stationary state the C is at rest with out side fully open and the inside has 2/3 open so to catch wind
from both sides.
As in MR Bernd post it may be better to up the C to 4-5 inch but I well test a 5 blade unit at 4 inch C and the plate is at 9 inch now it would be easer to add some longer
arms to push out the blades to 40 or so inchs as so that 3 blades at a time are in the push of the wind at all times.

Bob Mann
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Re: New C Rotor with free flooting C

Beitragvon labitrail » Mi 7. Dez 2011, 20:04

sounds very interesting, Bob. I will wait for your results an then I will try to test the best combination if possible in a wind tunnel.
Bye, Bodo
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Re: New C Rotor with free flooting C

Beitragvon BobMann » Sa 10. Dez 2011, 02:40

I finished the new C flooting Rotor Blade and tested it on the spin test stand.

Here is the raw data some one will need to do some math for me to see if this works.

The Stock stand no wings takes 406 watts to spin with new blades at 100RPM

The new C Flooting Rotor Blade one blade takes 664 watts to spin at 100 RPM

Spining it backwards at 100 RPM free flooting stays in the middle most of the time is 726 Watts.

If you lock it in the out side most spot or inside most spot it is 670 Watts of power to spin it.

This is a 4 inch half drain pipe foot print.

All three C blades moving forword at 100 RPM is 727 Watts

backwards is 1086 Watts this plates are at the Lenz 7% mount point

Now for the Lenz one blade used at 100 RPM forword is 870 Watts and it running backwards is 1311 Watts

here is the vid
http://www.youtube.com/user/CNGBOB?feature=mhee
Bob Mann
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Re: New C Rotor with free flooting C

Beitragvon labitrail » Sa 10. Dez 2011, 16:38

Looks good. I will come back with some drawings to talk about the same shapes and figures.
cu Bodo
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Re: New C Rotor with free flooting C

Beitragvon Bernd » So 11. Dez 2011, 10:38

I think the difference between the diameters of the half tubes of the Lenz and the C-Rotor ( 7 and 4 inch) is crucial
for the different results you got.
To compare them really fair they should have the same dimensions i think.

Grüsse

Bernd
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