The Continuing Turbine Saga

[Arletta]

Well, as luck would have it I spent my designated turbine building time trapped in the office, making little depressing turbine models out of Post-it note pages. The frustration of gainful employment.

However, progress has not been totally elusive. Working late into the night, I managed to remove the two little plastic ridges from the top of my 5 gallon bucket, so now all I have to do is cut it in half once my blistered hands heal a bit. Perhaps I should consider expanding my tool collection. My swiss army knife is very versatile but there is a limit.

I was idly looking at a Rockler woodworking catalog last weekend and noticed that they sell hardware for those rotating cabinet shelf things...essentially two metal disks on an axle, fifteen bucks. Wonder if those would work for my turbine. One could somehow stick the plastic vanes to the disks, leaving a tiny space between the inner vane edges and the axle. Then affix a short piece of pvc pipe over the base of the axle, to the bottom of the lower disk. This tube would then be the active axle which would turn the alternator. May make the turbine more efficient since the vanes wouldn't have to overcome the weight and resistance of a full length axle.

On the other hand, the air space between the vane edges and the axle might defeat any increased efficiency.

Thanks for the comment, Demetri...know what you mean about the neighbors. Mine already think I'm a bit strange and when they see me standing on the roof with my turbine they'll probably call the funny farm.

On your turbine did you twist the vanes around the axle or just put them opposite eachother like a basic Savonius shape? I'm having trouble figuring out how wide to make the vanes in proportion to height and how much twisting them really increases efficiency. My pop bottle prototypes seem to work pretty well with narrow, minimally contorted vanes but manufactured turbines seem to have the twisted hourglass shape.

As I type the wind is picking up, inspiring me to go find some bandaids and a pair of leather gloves and get back to work on this.  

[Demetri]

My design didn't have any twist to the blades, too much hassle. There was no overlap, just the edges of the blades butted up against the axle. Seemed to work quite well, though were I to build another to drive an alternator I would make it twice as tall, using two buckets, and stagger the blades, to make a four bladed mill instead of two long blades. I switched between a hacksaw and a propane heated soldering iron to cut my bucket up. The Tiger didn't do too well, just tore up the first bucket. Many pieces. Hope this helps.

Demetri

[Norm]

  If only you could post a couple little pics of your projects...a pic is like a thousand words or lacking a camera you could draw a picture. I just used a plain pocket knife to cut my 2-liter pop bottles, except for the top part which is a little tougher, where I resort to a sabre-saw, haven't lost any fingers....yet! To deal with the neighbors, you just disguise them as ornamental windmills...like a duck with wings and then just keep  making em bigger, until one day the neighbor is looking at an ornamental duck with an 8 foot wing span thats puttin out about 800 watts or so!(:>) have fun!   Norm.  

[Gordy]

Arletta,

    From what I have read on the VAT's there are two main reasions for putting the twist in the buckets. One is to make them easier starting in low winds, the second is to reduce the torque impulses as the buckets turn in and out of the wind. Which can cause viberations and posible pulsing in the generated power. One option is to build your mill in section 2,3,4... sections high and offset each section from the last one. When looking down from the top a 2 section mill would be offset by 90 degress (+), 4 sections would be 45 degress. That way part of the mill is always catcing the wind.

     Do a google search for Pico.com or Picoturbine.com it is one or the other, anyway it is a neat site.

                                                      Good luck,

                                                      Gordy