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Forum Index : Other Stuff : pvc pipe blades
| Author | Message | ||||
| need2know Newbie  Joined: 16/06/2008 Location: United StatesPosts: 5 |
I have been experimenting with pvc pipe as a source for blades..I make them on my table saw cutting 6 inch pie into 3 pieces, Then marking and cutting from the outer edge being 2inches wide down to 6 inches with a cut down to about 2 1/2inches wide. This is bolted onto a hub. Does anyone have any suggestions as to how I can beef them up for strong wind? lottolearn |
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Dodgeman Newbie Joined: 19/07/2008 Location: United StatesPosts: 33 |
heres how I beefed mine up, I knew, with 4 feet of blade (6 inch, schedule 40 pvc, cut into 4th's) that I would need more than the roughly 7 inch circular size of the hub to hold them on, so I added 3- 4 inch, blade supports at 120 dergees evenly. Now, instead of 2 botls holding the blades on I have 4, I also did not cut out the blade at the root end of the blade, I dont know if this impedes performance or not, but on a smaller mill I made, without blade supports and with cut outs at blade roots, they broke off at the cut, in strong wind, hense, the new design with support 
Here is a pic of the cutouts (or lack thereof, in my case) I am talking about. 
Hope that helps some |
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| need2know Newbie Joined: 16/06/2008 Location: United StatesPosts: 5 |
Thank you dodgeman. I hadn't thougth of additional arms for each blade.However, I made three blades with 6 inch pipe. Each blade is about 6 inches at the root so some cutout is necessary. lottolearn |
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| domwild Guru  Joined: 16/12/2005 Location: AustraliaPosts: 873 |
If I see it correctly, you are using one strap from hub to prop. I use two, front and back. That should beef it up. Jerry of Fieldlines fame suggests using an alu sandwich front and back. Mentioned this before: Use primer, which sticks to tiles, PVC, etc. (Bunnings) and then paint prop white or silver to guard against UV making it brittle, ready to fly away. Good luck! Taxation as a means of achieving prosperity is like a man standing inside a bucket trying to lift himself up. Winston Churchill |
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Gizmo Admin Group  Joined: 05/06/2004 Location: AustraliaPosts: 5031 |
I agree with Dom, use a strap both front and back. The root area of any turbine is the most stressed part of your whole windmill, you need to make it strong. When the windmill turns to face the wind or furl out of it, the gyroscopic forces will be trying to tear the blades off at the root. On my 6 blade turbine with PVC blades, I use a larger metal plate at the back to support the blade and tilt it at the correct angle. On the front I have another smaller metal plate that will stop the rear plate bending back ( its happened! ), and reduce any twisting in the blade when the windmill furls. 
Glenn The best time to plant a tree was twenty years ago, the second best time is right now. JAQ |
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