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#Post#: 729--------------------------------------------------
Blade construction and Weight
By: lynx wind Date: November 2, 2013, 12:50 pm
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The blades for the Gull 160 are 19.75" long by 7" wide. They
are made from foam cut to the airfoil shape and then wrapped
with styrene plastic. They are very stiff and light. The
styrene has to be painted with a dark color and then a top coat
to protect it from UV. I use "Fusion, Plastic Paint" from
Krylon.
The weight of the Gull 160 blade section is 105 grams (3.75 oz).
The weight of the Gull 40 blade section is 28 grams
It is important to keep weight down so that the Turbine is
responsive in changing wind speeds.
It would be interesting to catalog in this thread the various
weights of blades and construction materials and techniques.
And then add comments on the performance in real wind testing.
#Post#: 738--------------------------------------------------
Re: Blade construction and Weight
By: crazyguy Date: November 3, 2013, 8:31 am
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More tips on Coroplast:
I have done experimentation and on-line research and it seems
that there is no glue that will reliably stick to Coroplast
(Polypropylene).
One method has you actually 'flaming " the surface then using a
special super glue.
Coroplast seems to be an ideal mechanical material to make these
blade skins out of.
So it seems the only way to do it is mechanical also.
The high temp hot melt glues seem to work somewhat and when I
had something for it to grab to mechanically, it couldn't be
pulled apart. So I came up with the following idea.
If anyone has other ideas they will be welcome.
[attachment deleted by admin]
#Post#: 750--------------------------------------------------
Re: Blade construction and Weight
By: lynx wind Date: November 3, 2013, 8:16 pm
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Here a couple photos of the blades for the Gull 160 and Gull 40.
The spars are 1/2" diameter fiberglass for the Gull 160, 1/4"
for the Gull 40. The foam is first cut and then the .020"
plastic is pulled over and glued on and seamed at the TE.
I found cutting into the spar hole at an angle helped the slit
to close back up when done.
The foam can also be painted with several coats of latex for a
nice finish.
[attachment deleted by admin]
#Post#: 754--------------------------------------------------
Re: Blade construction and Weight
By: crazyguy Date: November 4, 2013, 8:18 am
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I know one thing for certain. the heavier the blades are the
more stress on the whole system and the harder it is to get it
started.
The carbon fiber rods at the hobby shop are not that expensive
for three blades probably $30 total.
Just a side note: This is the most expensive battery charger
I've ever built.
#Post#: 755--------------------------------------------------
Re: Blade construction and Weight
By: lynx wind Date: November 4, 2013, 8:31 am
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Yeah, a heck of a way to charge a battery.
Probably why there only a couple hundred people doing this. But
who will have the last laugh when the power goes out?
It's not a bad idea to know a little technology for harnessing
some power via water, solar, wind or fire.
One other thought is these wind turbines should cost about as
much as a cheap vacuum cleaner. I am sending two turbines to S
Korea today and I suspect they will reverse engineer them and
make them for $50. I don't mind. Then I can buy a couple
instead of making them.
#Post#: 770--------------------------------------------------
Re: Blade construction and Weight
By: crazyguy Date: November 6, 2013, 2:20 pm
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I made one half blade today. It has three wood ribs and a 3mm
Coroplast outer skin. I used hot melt glue. The blade came out
nice but took a long time due to having to wait for the glue to
set . The difficulty with the hot glue is , you can't just lay
down all the glue and then wrap it around
the spars and ribs, it just sets up too fast. So you have to
do a little at a time. It is 17.5" span 5.8" cord and about 1 "
thick. The weight without the spars is 134 grams.
Since my Lynx SeaGull came down due to a damaged support line I
have to re make the turbine. This time with Coroplast blades
instead of maple wood veneer.
The wood veneer, I thought was sealed against the elements but
somehow moisture got inside and ruined them.
#Post#: 829--------------------------------------------------
Re: Blade construction and Weight
By: crazyguy Date: November 15, 2013, 3:03 pm
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All Coroplast blades are done.
2 are installed on the rotor.
It's actual three times as much work replacing all the blades,
than building the whole VAWT.
I have to get this up soon or it will have to wait until
spring.
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