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#Post#: 1429--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 4, 2014, 9:22 am
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Great!! I had saw the video but didn't know ho good it stuck !
also @LW has never said how much the TE affects the turning of
windmill (does it have to come to a sharp point or can it be
folded like above )
#Post#: 1430--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: February 4, 2014, 9:30 am
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Good work guys. I would experiment more but it's so damn cold.
My garage with a heater is about 25 F.
I use Goop a lot and it is very good and very strong. But I
also have had TE's pop open and it is maddening. The reason the
bent over TE is superior is that it will tend to spring together
tighter and I would trust an adhesive because the support is
aluminum and not glue. The only way the blade could fail is if
the TE bend breaks off, but the loading on that bend is very
low.
My goal is to make a turbine that will run without attention for
ten years or more.
I'll get the exact dimensions of the Gull 360 worked out. The
chord length will be about 11.5" and each section will be 29.25"
long. So the rectangle will be about 24 X 29.25" What gauge
aluminum are you using? I would think a sheet metal shop could
cut these sections and put the fold in for a couple bucks each.
There is some nice white painted aluminum .080" at Midwest
Metals. They will cut the sheets. The 48" wide sheet could be
cut in two for 24" strips and lopped off.
#Post#: 1433--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 4, 2014, 3:00 pm
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LOL I agree on speed demons !! I measured the trim stock it's
.018 the new stuff I just bought is .013 thick I don't know
what gauge that is but the mic is better
I just took mine down and brought into the garage to thaw it
out! it had 12" of snow and ice on the rotor (nothing on wings )
! I heat my garage to 45 all winter don't want things to freeze
like me
#Post#: 1444--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: February 5, 2014, 4:28 pm
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I think the bamboo blades are fine for the DIY. Keep in mind
with the DIY 75 the fiberglass and blade shape was an integral
part of the design. The wood dowels aren't strong enough for
anything but locating the blade. Bamboo might be as rigid. I
don't think thin aluminum is strong enough without ribs. I
think they could buckle outward in the middle and the wood
dowels would break.
If the aluminum is thick enough and the TE is secure, the shape
could be quite strong.
Thank you for doing so much experimenting and innovation.
#Post#: 1450--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: February 5, 2014, 9:05 pm
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I like the bamboo. It may even hold up better than most
materials. Here's my issue. When I get orders for turbines, I
have to make 6 blades and they have to look professional, but
they are time consuming and it makes me search for some method
for high production. If I can get all the parts made by vendors
then I just have to package and ship. This is just my problem.
The other issue for me is using strong, light materials that
will last years. They can't swell with ice, delaminate,
deteriorate in water, flake or succumb to UV. It's a materials
issue.
Britain ran short of materials during WWII and made one of the
best fighters of the war with wood. The Mosquito was fast and
light.
The question about the US VAWT. It was a 36"T x 36"D. It had
one spar. This worked quite well up to about 17 mph. In fact
for a fleeting moment it beat the BETZ limit by two watts. This
experiment was where I started seeing the outward force on the
TE. Learned a lot from things that broke. The blades were
Spyder blue Foam used by surfers. The rotors were too light and
would twist.
The solutions that came from this early work
1. Two spars
2. much stronger one part rotors
3. bearing below
4. single phase
5. bracing
6. single central rotor.
#Post#: 1451--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 6, 2014, 8:21 am
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@ CG the aluminum your using is to thin it has to much memory I
have used that type before on my other vawt and what I found out
was I had to pull it while bending around the former and screw
it while I had tension on it, then it worked fine. The heaver
stuff that I have been using still has spring back but you can
get around that by working it with your hands into the shape you
want . (remember I have only 2 formers in my wing ) I don't
think you will ever dent the aluminum wing its really a strong
wing after you get it all glued up. (I could be wrong ) The only
spots I could see denting would be the sides but then it may
just spring back to its original shape unless it was something
that had an sharp edge and creased it. (kinda like hitting a
side panel on your car it moves but springs back) So far I have
not saw any deterioration of the wings on my diy 75 they are
holding up great! BUT as i speak the windmill is just sitting
there so its not like its getting a great amount of windy
testing . I keep saying I will run it unloaded just to see where
it fails but when i see it spinning in a 40 mph wind I change my
mind!I am surprised it didn't come apart then.
#Post#: 1482--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 9, 2014, 7:41 pm
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I think its 18 "or 24 the next size up, the one I bought was
14" and was long enough to make all the blades! the cheapest
place I found was Menard's . Take a mic with you because it
doesn't give you a thickness on coil. I just use a razor blade
knife to cut it ! you have to make several passes to get it
close enough to get it to break but it works great and that way
you keep it flat unlike using a pair of tin snips which will
give you a jagged edge and an arch to your metal
#Post#: 1485--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 10, 2014, 7:49 am
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The only things I can see going wrong are 1. the weight of the
wings may vary by a lot 2. the wings may loose shape because
of foam pushing out unevenly (female formers needed ?) 3.Messy
and how does foam stick to the aluminum 4. things going
completely right and you have a perfect wing !
Speaking of wings are they symmetrical? I know when I made mine
for the diy 75 they were but are they for the bigger Gull 160
this may make a big difference on a bigger wing ? if they are
not symmetrical does the flat side go on the inside or outside
#Post#: 1486--------------------------------------------------
Re: Alunimum wings for diy 75
By: lynx wind Date: February 10, 2014, 8:24 am
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The Gull 160 and 40 have a little different shape airfoil from
the Seagull. I have used NACA 0020 with very good results. The
Gulls have a hybrid airfoil. Take a NACA 0020 and splice a NACA
0024 on the outside. I put the fatter airfoil to the outside.
There, now all the guys in Asia can make a Gull. It's Ok, I
already have sold several to China and Korea. I am sure they
will be on the market soon and we can buy one for $40. That
will save us all a lot of trouble.
I agree that filling an aluminum skin with foam is going to be a
challenge, but it is worth experimenting. Make sure to ay down
some plastic tarp and wear gloves!
#Post#: 1493--------------------------------------------------
Re: Alunimum wings for diy 75
By: sut Date: February 10, 2014, 4:49 pm
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I hunted this down on you tube about spot welding aluminum
HTML http://www.youtube.com/watch?v=gcgC3V3mkcw
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