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Forum Index : Windmills : Securing blade hub to rotor

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imsmooth

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Joined: 07/02/2008
Location: United States
Posts: 214

Posted: 02:54am 22 Apr 2008

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I will most likely drill some holes in my hub and screw it to the magnetic rotor. The rotor, however, is conical and slants, while the blade hub is flat. How do you screw the two securely together? Does two bolts per blade spoke sound reasonable? My blades will be 4.25 feet.

Gizmo

Admin Group

Joined: 05/06/2004
Location: Australia
Posts: 5116

Posted: 06:53am 22 Apr 2008

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I wonder, has anyone tried filling the hub with epoxy to make it stronger. If you blocked up the drain holes, you could fill both sides with goo, making that ribbed section between the spline and the magnet ring a lot stronger. Of course on the inside you would have to be carefull you dont over fill and foul the stator.

Once filled, the blade mounting holes could be drilled to suit whatever blades you use.

Just an idea, I really should have a look at a hub to see if its do-able.

imsmooth, I would use more than two bolts. The hub is the most stressed point of your turbine, especially with it furls.

Glenn

The best time to plant a tree was twenty years ago, the second best time is right now.
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dazz
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Joined: 15/04/2008
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Posts: 78

Posted: 08:22am 22 Apr 2008

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I have done similar things with polyurathane. If you cap the holes from underneath(with say bottle tops attached over the holes with silicone) then the resin will flow through the holes and form a rivit to hold the large mass above. Otherwise the mass would need to be screwed on to stop it falling out.

One thing to consider is the added weight of the resin will add to the momentum of the hub a little. this may or may not be relevant for light wind starting

Daryl

dazz
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Joined: 15/04/2008
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Posts: 78

Posted: 08:24am 22 Apr 2008

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on second thought, bottle tops might be a bit big and get in the way of the rotor. but you get the idea :)

Also, the hub would need to be placed on a very level surface for pouring, otherwise the resin would not set parallel to the hub. This would result in the attached blades to wobble through rotation

Daryl
Edited by dazz 2008-04-23

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