The initial model of the "slatmill" was built from fiberglass reinforced plastic cut into discs and then quartered 3" Schedule 30 PVC pipe. I'm trying to provide good instructions for things as we go, but I'm getting behind on writing and the pictures for this one pretty much say it all, so if you have any questions just drop me an email and I'll try to explain any confusion!
The model proved to be great at grabbing small amounts of wind, and despite being only built to prove the concept, was pretty hearty! It did meet it's final doom after a few months in operation, but I knew the hot glue that held the fins on wouldn't hold forever. Concept proved, on to the more-power version.
|The discs can really be made from anything tough enough to hold the weight of the fins. I used what I had handy, you should too. There's no magic here, just use some hard object with a pair of holes as a protractor to make a good circle. Once you have a nice disc (ours happened to be 18" in diameter because that's what size scrap I had) just drill holes around them so that the holes are equally spaced.|
|In this model, since I didn't know for sure what I was doing, one of the design goals was to be able to adjust the pitch of the slats to find the best angle for the design. So, because they needed to be moveable, the slats weren't any use for structural support. I looked around and decided this "Z" aluminum would do nicely, so I cut some chunks of hardwood and then chiseled out the profile of the aluminum stock so it could be pounded in (once for the top and once for the bottom).|
|Not pretty, but it was pretty effective. Some simple angle brackets would do the same job and be less work, if they'd been handy.|
|With the aluminum (sort of) firmly fixed in the wood, I just bolted the wood to the center of the two discs.|
|Almost done, just bolt the bottom disc on and get the slats ready.|
|The PVC pipe is just cut lengthwise to get it in quarters. I used a cloth ruler to figure out a quarter of the circumference and then mark it. Pressing the pipe up against a straight edge let me draw a good line, and then I just cut down each of them with a jigsaw. Because I needed to be able to adjust the angle of the blades, we glued them to dowels that would be moveable.|
|All glued up and ready to go. (Wood glue won't stick to PVC for anything, in case you're curious.)|
|After the dowels were attached to the PVC sections and the discs attached to the "frame", we just slid them in. I used tough tape to hold their angle.|
|All done. My little brother Elijah was assisting on the surgery. :) I had already machined a hub to attach to my rod and bearing test stand, so we bolted that to the center of the bottom disc and put it on the test stand.|
|Kind of majestic looking, huh? Notice how little the leaves in the tree right behind it are moving! Of course the model wasn't being slowed down by a generator yet, but it's catching wind!|
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