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Author Topic: with blades to use  (Read 2494 times)

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honda

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with blades to use
« on: July 02, 2009, 03:00:33 PM »
new to site,and wood like to say hi, and could use some help on with blades to use on my windmill,and solar set up,shoud I use 5 blades or 3 blades my generator put out 12volts-3.50amps-at330rpm and at 700 rpm it make 25 volts and 7amps who sell the the best blades,that I can used,   thank you  honda        
« Last Edit: July 02, 2009, 03:00:33 PM by (unknown) »
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ghurd

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Re: with blades to use
« Reply #1 on: July 02, 2009, 09:31:52 AM »
I get the feeling the measurements were open volts and shorted amps.

Not the best way to measure for output.


I am guessing it will make about 3A into a 12V battery at 700 RPM.

Consider making PVC blades from thick wall 6" pipe.  Maybe 42" diameter.


Can carve wood blades for better performance when you know more about the operating parameters.

Might be a decent match for Rich H's 18" each CNC blades, if he is still selling them.


Three will be better than 5 blades for it.

G-

« Last Edit: July 02, 2009, 09:31:52 AM by ghurd »
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gotwind2

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Re: with blades to use
« Reply #2 on: July 02, 2009, 12:34:40 PM »
I agree with Ghurd.

The quickest and easiest method is to maybe start with some pvc pipe to find what blade diameter works with your alternator in various wind speeds, start large, and you can always chop the blades down 5ft,4ft, 3 ft maybe.


Wooden blades will perform better, but the pvc route will give you some idea, and in my experience they performed pretty darn well.


Heres on of my 4 ft diameter blades attached to an Ametek motor.




« Last Edit: July 02, 2009, 12:34:40 PM by gotwind2 »
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Onthero

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Re: with blades to use
« Reply #3 on: July 03, 2009, 08:30:03 AM »
hey gotwind2, let me pick up on your blade design, are'nt your blades mounted wrong ?!


I think it would lead to much better performance if you make the straight edge of your blade (wich is now the trailing edge), the leading edge.


Here i see the same:


Also many other PVC blades seem wrongly mounted to me.

« Last Edit: July 03, 2009, 08:30:03 AM by Onthero »
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Simen

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Re: with blades to use
« Reply #4 on: July 03, 2009, 01:51:41 PM »
Gotwind's blades are perfectly ok; they'll just turn CCW. ;)


Yours turn CW.


Cornelius

« Last Edit: July 03, 2009, 01:51:41 PM by Simen »
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Simen

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Re: with blades to use
« Reply #5 on: July 03, 2009, 01:52:52 PM »
Oh, sorry; i mean the other way around. :D
« Last Edit: July 03, 2009, 01:52:52 PM by Simen »
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I will accept the rules that you feel necessary to your freedom. I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do. - (R. A. Heinlein)

Onthero

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Re: with blades to use
« Reply #6 on: July 03, 2009, 04:21:03 PM »
Ok then, but from an aerodynamic point of view, it seemed better to me that the strong curved edge tnow the leading edge) would be the trailing edge, but ok, if you guys are sure it will have no influence on performance .. (i find it quit bizarre but ok)
« Last Edit: July 03, 2009, 04:21:03 PM by Onthero »
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tlaycock

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Re: with blades to use
« Reply #7 on: July 03, 2009, 05:49:43 PM »
I see a problem with the second picture of blades. They look like some type of wood blade. The end view of the blade shows the air foil backwards ??


The first picture is correct for plastic pipe blades and direction of turn is to the straight edge.

« Last Edit: July 03, 2009, 05:49:43 PM by tlaycock »
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Onthero

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Re: with blades to use
« Reply #8 on: July 06, 2009, 04:43:20 AM »
I think the airfoil is correct for the direction it wil spin (CCW).

Can anyone confirm this ?
« Last Edit: July 06, 2009, 04:43:20 AM by Onthero »
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Capt Slog

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Re: with blades to use
« Reply #9 on: July 07, 2009, 04:31:03 AM »
They look fine to me, and CCW it is.


.

« Last Edit: July 07, 2009, 04:31:03 AM by Capt Slog »
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