Author Topic: Glass fiber blades vs. wood blades  (Read 1823 times)

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rinaldoparaipan

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Glass fiber blades vs. wood blades
« on: January 19, 2013, 02:18:50 PM »
Hello everybody.
After two years of tests I have some conclusions.
First I want your opinion and after I'll tell you my point of view.

birdhouse

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Re: Glass fiber blades vs. wood blades
« Reply #1 on: January 19, 2013, 03:08:25 PM »
i think the question is a little open ended. 

are we talking about homebrew blades?  large sized hombrew blades?  small commercial blades, or large scal MW+ turbine blades. 

i'll concentrate on smallish hombrew blades. 

i think the best medium is whatever the builder is comfortable with using, as well as what assets the builder has in his/her shop. 

sure, if you've got a three or four axis mill, vacuum bagging equipment, and the knowledge on how t use it all, fiberglass is probably better. 

however, if you own a saw, a chisel, a sander and a paintbrush, wood is probably far superior for that particular builder. 

for my blades i kinda split the difference.  i carved them from laminated wood blanks, then put a layer of fiberglass over the top.  then coated liberally with two part paint.  1.5years up, and they still look like the day they were installed!

adam


clockmanFRA

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Re: Glass fiber blades vs. wood blades
« Reply #2 on: January 19, 2013, 03:13:34 PM »
My first set of 3.6m diameter Hugh Piggott designs were cedar and are very light and very durable, I coated them with Vinyl ester resin. They have been up 4 years and get a coat of fresh paint every 18 months or so.

Now for the rest of my 3.6m wind Turbines I make Fiberglass but still the exact copy of Hugh's design. My real reason was that getting good cedar that is quarter sawn has proved very difficult.

My moulds are very rigid and bolt together when foam filling. The blade half's are simple and fun to make, but the internal I beam and the cutting for the blade joint of the 2 half's is a right pain and very fiddly.

Also after a few years my first set of fiberglass blades all fractured on the leading and trailing edges down at the root, so the I beam must be well joined to the internal root ply filler, (necessary for the screws to bite
 Into).

Fiberglass blades are also twice the weight of my Cedar ones. But I will carry on making them and giving them a good test.

Pic1, blade joint fracture.
Pic2, shows moulds for 3.7m dia set of blades, left side are the matt cutting templates.



« Last Edit: January 19, 2013, 03:25:35 PM by clockmanFRA »
Everything is possible, just give me time.

OzInverter man. Normandy France.
http://www.bryanhorology.com/renewable-energy-creation.php

3 Hugh P's 3.7m Wind T's (15 years) .. 5kW PV on 3 Trackers, (11 yrs) .. 25kW PV AC coupled to OzInverter MINI Grid, back charging AC Coupling to 48v 1300ah batter