Author Topic: Wind speed power verses Generator Power out  (Read 16126 times)

0 Members and 1 Guest are viewing this topic.

Offline niall

  • Sr. Member
  • ****
  • Posts: 299
  • Karma: +16/-0
  • No Personal Text Set by User
Re: Wind speed power verses Generator Power out
« Reply #45 on: February 18, 2012, 06:49:15 pm »
hope this is on topic ... :)

i,d go a bit further with the issue of home made blades ....i think you can actually compete very well  with the commercial blades ...it,s a matter of personal choice i guess..

its pretty easy to "knock" up a constant pitch , constant chord ,no taper wood blade....that,ll work just fine

now... if you have extra time on your hands , (and your a bit nuts) you can use a blade calculator and make the non linear twist ,graduated chord , taper blade .....you can even feather the trailing edge to a razor point if you wish .... :)...get a ultra smooth leading edge etc....

going after these traits might seem a bit extreame ....but the side effect often overlooked (i think) is that you get a stronger quieter blade .....

if you really want to get certified you can play with winglets at the blade tips ....and yes it has to be fun ..... :o

the best part is your in controll of your own machine ....you can replace the parts , if you need too

 

Offline ChrisOlson

  • Hero Member
  • *****
  • Posts: 510
  • Karma: +29/-5
  • just trying to survive
Re: Wind speed power verses Generator Power out
« Reply #46 on: February 18, 2012, 07:01:18 pm »
Oh, I'm not going to knock homebrew blades.  If you're skilled enough you can match the commercial ones.  After all, somebody has to build the commercial ones too.  It's just that I'm pushing Cp .40 with those S809's.  I like that airfoil and it's really hard to carve it.  It was designed by the NREL, specifically for wind turbines, to be forgiving of dirt, ice and roughness on the blade surface.  They run fairly quiet at high tip speeds.  And I like the glass blades because glass never soaks up, or gives up, moisture or changes weight or density with age.
--
Chris

Offline niall

  • Sr. Member
  • ****
  • Posts: 299
  • Karma: +16/-0
  • No Personal Text Set by User
Re: Wind speed power verses Generator Power out
« Reply #47 on: February 18, 2012, 07:18:37 pm »
hi Chris.... :)

yes ....that airfoil seems almost impossible to carve....and moisture content in wood blades can throw out balance a little .....

buying commercial blades seems tricky .....theres so much iffy stuff out there

sorry for going of  topic a bit ... :)

Offline bvan1941

  • Full Member
  • ***
  • Posts: 113
  • Karma: +5/-0
  • No Personal Text Set by User
Re: Wind speed power verses Generator Power out
« Reply #48 on: February 19, 2012, 11:26:44 am »
Chris,
I agree that the design of the S-809 blade takes sophisticated equipment and to evaluate the foils ability. The part of your statement that has some error in it is the belief that "fiberglass is impermeable to moisture(water)! Wrong--- fiberglass is actually just a big sponge without a waterproof layer applied and chemically bonded to the fiberglass.
 In fact if one were to look at raw fiberglass under a strong magnifying glass or microscope. one would see thousands of holes in the material. (The holes are microscopic gas /air created in the mixing and chemical reaction of the resin catalyst mixture). The only thing that keeps boats or anything made from fiberglass watertight, is a very thin layer on the outside that's called"gelcoat."If the people in this forum would cover their fiberglass with "gelcoat" when they take the stator out of the mold, they wouldn't have moisture get in and start the delaminating of the fiberglass. Another little known fact when dealing with fiberglass (polyester,vinylester,epoxy resins), is all resins bought off the shelf, has liquid wax mixed into it. This is what make the fiberglass "smooth to the touch," otherwise it would be "sticky" to the touch and stay that way for quite a while.

When applying "gelcoat" to "cured fiberglass" one MUST LIGHTLY SAND OFF ALL THIS OUTER LAYER OF WAX that comes to the surface during the curing process in the mold. Gelcoat can be put on by brush, roller or sprayed, your choice. Two coats applied immediately will negate the required sanding necessary if allowed to dry between coats. This procedure also applies when building up multiple layers of fiberglass as well. Unless your using resin without wax already mixed in the resin, the "rule" is apply successive layers before the curing is complete (meaning, while the previous layer is still "tacky" and before the wax rises to the top of the fiberglass).

Just trying to help (Thirty years of fiberglass work repairing boats !!!)
Bill


Offline Wolvenar

  • Senior Moderator
  • Hero Member
  • *******
  • Posts: 1474
  • Karma: +40/-0
  • Mr. Murphys pawn
Re: Wind speed power verses Generator Power out
« Reply #49 on: February 19, 2012, 05:33:12 pm »
Couple notes on applying a gel coat..

This stuff is rather dangerous, you MUST have the correct equipment and respirators, or risk serious health problems.
Another possible solution is a couple step process. I have used a thick polyurethane paint, like a bed liner ( Herculiner ).
I strain out the rubber pieces, then use it for boat bottoms etc. As polyurethane does not hold up well to UV, there are additional polyurethane
compatible coatings meant for this problem.  Downside in this is this turns into a relatively thick coating, but it works well for at least a decade, and is much less toxic and expensive to apply. Gel coat is relatively thick also, so the results may be comparable.
Trying to make power from alternative energy any which way I can.
Just to abuse what I make. (and run this site)