Best DIY config for rotating frame on mast?

Discussion in 'Frame Construction' started by AdironDoc, Nov 4, 2010.

  1. AdironDoc

    AdironDoc WindyNation Engineer

    Got the threaded rod in and added a cheap tail section. Decided to lose the spring and hinge... too prone to weather. The hole in the PVC is offset and results in a furling up to a certain point (around 110 degrees) at which point it binds and is difficult to bend further. A very strong wind may still overcome this. Any ideas on how I could put a stopper on this design?


    Tail Section and Furling Axis
  2. timber

    timber WindyNation Engineer

    Hi AdironDoc,

    A couple of pieces of your 1" square tubing mounted with 2ea. 1/4" or 5/16" bolts to your existing square tubing might work for stops.

    Note: At one time a while back, I tried using PVC as a blade material.
    It was easy to work with and the blades worked great but UV rays in combination with cold conditions made them very brittle.
    My blades ended up over 100 feet away in different directions when we had a nice strong wind one winter day.
    I would be somewhat concerned about using PVC for any long term solution.
    Would it be possible to replace the PVC with Sch 40 or even Sch 80 steel pipe.
    The stronger you build this, the longer it will last without problems.
    Just a thought.

  3. AdironDoc

    AdironDoc WindyNation Engineer

    Ah yes, good point. I was wondering the same when I used the PVC. Although there's very little weight on the tail section, it will potentially be snapping up against the stopper. I thought, in the icy deep of winter it could shatter. I'll be looking for a section of lightweight steel tubing, maybe EMT, which aside from potential bending, would never crack or break.

  4. windyguru

    windyguru WindyNation Expert

    Do not use PVC for any situation where it will be in tension or shear. Compression is probably OK in some situations, for instance, like a bushing where a ~500 Watt wind turbine sits on a PVC bushing. And only use it in compression where the PVC will be out of the sun light.

    Now, there are of course many, many exceptions to what I just said but the point is you do not want to do mechanical engineering load calculations to find out if the piece of PVC you want to use will be strong enough. Odds are it will not be and it will eventually snap and if it does not snap the UV from the sun will eventually break it down. My advice is to stick with steel for any part that your common sense tells you that "this part probably needs to be strong".
  5. AdironDoc

    AdironDoc WindyNation Engineer

    Ok, so I'm almost finished with the frame. To protect the turbo-torques, I will slide a threaded 1/4" rod laterally through the galvanized frame and bend it upward at 90 deg. This should prevent the aluminum tail section from bending beyond 90. When I have it painted up (I'll leave the plexiglass vane clear), I'll take another viddy. Until then, he she is...

    and moving, albeit slowly..

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