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#Post#: 573--------------------------------------------------
Alunimum wings for diy 75
By: sut Date: October 13, 2013, 2:46 pm
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I just made 3 of the 6 windmill blades ( ran out of aluminum) I
was amazed how easy it was using .0020 thick aluminum. The
process is a little different from the diy 75 plans, you have to
form the alunimum to the shape( I just used my hands ) then glue
in the forms on each end,after they are set up I glued the TE
last . The first wing I made I used clamps to hold everything in
place while the 5 min epoxy dried But learned that clamps were
not needed I just used masking tape to hold everything in place
. I weighed each blade and they came out at 220 g I don't know
how much the fiberglass wings weigh but I think these are
lighter . They have a little flex to them in the center if you
press in on the center of blade but I don't think wind will
cause it to change shape .I will put up some pictures when I get
my camera working
#Post#: 620--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: October 22, 2013, 7:28 pm
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This is my first video hope it helps and is easy to follow
[URL=
HTML http://img.photobucket.com/albums/v74/sujsti/aluminum%20wings/0001_zps34cd0969.mp4][IMG]http://img.photobucket.com/albums/v74/sujsti/aluminum%20wings/th_0001_zps34cd0969.mp4[/img][/URL]
#Post#: 621--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: October 22, 2013, 8:40 pm
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Excellent! Great Video. That may just be a lot easier than the
fiberglass blades.
I have had some problems with aluminum getting tweaked out of
shape under high stress. Once you crinkle the aluminum its
tough to fix. You may want a middle rib. But these blades are
short. The main stress I would look out for is yawing or fore
and aft. That can deform the leading edge (top blade) and
trailing edge (bottom blade) where it joins to the rotor. I use
a good amount of exterior silicone at that join to take some of
the stress.
#Post#: 623--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: October 23, 2013, 9:25 am
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@Lynx wind Thx I have been thinking about all the above and had
thought about trying some expanding foam inside but having never
used the low expanding foam before, I don't know how much it
expands . I am using fiberglass rods instead of wood dowels
inside ( I got my fiberglass rods from my local snow plow supply
shop, they are driveway markers) and hope they will take more
stress than the wooden ones . Today I was in Menard's (for some
other things ) and I noticed they sell aluminum trim coils 14" x
10' which would make all the wings for $12.00 (trim coil is
heaver than flashing ) so it shouldn't flex as bad if at all. I
will keep everybody posted on any problems I run into on this (
when I get it up in wind )
#Post#: 624--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: October 23, 2013, 3:03 pm
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I am really intrigued by what you are doing. The most time
consuming part of the manufacture of the Gull 160 and Gull 40 is
the blade. I have thought about having ABS plastic vacuum
formed, but what you are doing is very possibly a better
solution. Keep at it and keep us posted.
I would love to drop the price on the Gull 160 down to half what
it is now. And I would love to pay someone to make the blades.
PS, I have had bad luck with expanding foam making a mess and
distorting the shape
#Post#: 626--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: October 24, 2013, 9:24 am
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Humm ! Glad to hear you think my making of the wings is
intriguing and possible for your bigger windmills . I may be
interested in doing so but first I need to finish what I have
started and see if they even hold up . What is the size of your
gull 40 and 160 wings, I may have some ideas on making then
stronger and lighter easily
#Post#: 627--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: October 24, 2013, 3:08 pm
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The sections for the Gull 160 and Gull 40 are as follows:
Gull 160 - 19.75" long and 6.75" wide
Gull 40 - 9.875" long and 3.375" wide
Really the sections are not big. But the Gull 160 when put
together is bigger than it would seem.
I was thinking a sheet metal shop could cut the sections and put
a 1/2" fold at one side so the TE could just be tucked in and
sealed. The Gulls could have a rib former CNC cut and attached
at the rotor and blade winglet. Seems like one or two more ribs
slid down the spars could support the skin. On an airplane the
skin would be riveted to the ribs. Just thinking out loud.
#Post#: 630--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: October 24, 2013, 8:19 pm
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Yep all valid points ! I am not sure you will need any center
supports, but time will tell, The wing as it sets is very
ridged. I hope the epoxy does not crack I hate redoing things I
should of got right the first time. I also like the fold on the
TE it would make that last step much easier and add more
stiffness to wing, every time you put a bend in metal it gets
stronger . thx for the measurement on the 160 & 40 I an
surprised they are not much bigger
#Post#: 633--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: October 25, 2013, 8:12 am
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Some aluminum alloys will bend, others will snap. I have bent
flashing type with a hard fold and it works. I am sure a sheet
metal shop could cut 60 of these pieces and fold the TE for a
few bucks.
The Gull design will scale up. If someone wanted to they could
make 4' long blade sections on an 8 foot diameter (8' x8'
VAWT). The rotor would need to be beefier. The alt would need
to be scaled up which would give the proper voltage at the lower
rpms.
The reason I abandoned the taller VAWT form with multiple rotor
arm attachments is because of wobble, vibrations, bearing stress
and complexity. Having the VAWT spin like a top on a centrally
located bearing solves a multitude of problems.
#Post#: 635--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: October 25, 2013, 9:32 am
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Tell me about a good piece of plywood ! I am hoping that when I
fiberglass my rotor I will take out the bend in the plywood. (1
arm up 1/4 inch ) I will try using a piece of angle iron on
bottom to make it straight till Fiberglas sets . Or placing
weight on top of the top wings and having the rotor setting on a
flat surface . One thing nice about it getting colder outside is
the fiberglass will set up a little slower and give me more time
to get things straight. I should be doing this sat. so hopefully
I will have this project up in the air real soon.
@CG the aluminum I an using is trim stock that's .018 thick I
got from my neighbor, a siding guy (he uses it for doing trim on
windows) so you can bend it many times without breaking
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