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Author Topic: 2 blades vs 4 blades at 48 inches.  (Read 1376 times)

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Paulm

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2 blades vs 4 blades at 48 inches.
« on: November 29, 2004, 05:13:06 AM »
I am at the stage of making my blades. I like the idea of using ABS 4 inch pipe. With a generator that my require higher than average rpm which would be better ? 2 or 4 blades? I have tall trees and some tubulance. My test 2 blade unit did some shaking when turning quickly left and right. Is a blade design of four smoother during a turbulant wind? It seems hard on the bearing and mount on the pole with that shake, especially during high rpm.


Paul.

« Last Edit: November 29, 2004, 05:13:06 AM by (unknown) »
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test lab guy

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #1 on: November 29, 2004, 06:32:08 AM »
The two blade rotor during yaw will shake just like you have expirenced.  The four blade will perform much better in yaw, but will run at a lower tip speed.  Are you choosing 2 or 4 because you have a hubless design going with the ABS pipe?  Is 3 blades with a hub an option?  


I have an idea to throw out for discussion.  It tends to violate Hugh's keep it simple rule, but here goes:  Run your 2 blade design and a yaw damper.  Use an automotive fan clutch and gear belt.  Run a small gear on the clutch mounted off to the side on the pole, a much larger gear at the bottom of yaw assembly.


I'm sure this has been tried or discussed before, I will search and post back if I find out more.


Regards,

TLG

« Last Edit: November 29, 2004, 06:32:08 AM by test lab guy »
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Paulm

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #2 on: November 29, 2004, 06:57:40 AM »
I'll prbably go with three blades.I like the look of 3 blades and it seems to be the standard on those HUGE industrial props. I'll use a metal hub on the shaft of my converted motor and attach the blades to it.


Paul M.

« Last Edit: November 29, 2004, 06:57:40 AM by Paulm »
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tizoo

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #3 on: November 29, 2004, 09:58:03 AM »
Hi, I'm very much interested in building a windpower generator... can you give info or tell me where I can get the information using 4"ABS Pipes for Blades. Thank You
« Last Edit: November 29, 2004, 09:58:03 AM by tizoo »
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Paulm

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #4 on: November 29, 2004, 10:19:39 AM »
Search this web site for PVC blades, you'll get some nice photos and info.
« Last Edit: November 29, 2004, 10:19:39 AM by Paulm »
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Jerry

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #5 on: November 29, 2004, 10:47:58 AM »
Running my 4 blade ABS I get 63 watts at 5 mph and 650 watts at 30 mph. This was on a 1 HP ac motor convesion. This was with 49" and 4 blades.


ABS Jerry blades are $15 each with Mike mods. $10 each without Mike mods.


                         JK TAS Jerry

« Last Edit: November 29, 2004, 10:47:58 AM by Jerry »
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wooferhound

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #6 on: November 29, 2004, 04:38:36 PM »
 Here's the basic plans to make PVC Pipe props . . .


http://www.fieldlines.com/story/2003/11/11/172721/53

« Last Edit: November 29, 2004, 04:38:36 PM by wooferhound »
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ghurd

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Re: 2 blades vs 4 blades at 48 inches.
« Reply #7 on: November 30, 2004, 01:08:00 AM »
You could get a commercial 3-blade hub and mount the blades to it?
« Last Edit: November 30, 2004, 01:08:00 AM by ghurd »
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