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#Post#: 696--------------------------------------------------
Re: Seagull DIY Discussion
By: nessprojects Date: October 30, 2013, 7:49 pm
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WOW !!
I agree with Lynx on that one, while you got no wind I would get
it bolted up before you loose it !!.
Wish I could post you some wind because I am fed-up with it at
the moment. (35Mph Gusts Today)
The torque on 75W will be about 1/10 of a horsepower.
Prevention is easier than the cure. (Learnt that one the hard
way unfortunately).
#Post#: 701--------------------------------------------------
Re: Seagull DIY Discussion
By: lynx wind Date: October 31, 2013, 1:14 pm
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The blades will tend to pull outward very hard in strong winds.
I have never seen any tendency for an inward pull in four years
of testing. I recommend straps from rotor to blade tips. That
hard outward pull is outward and forward.
In really strong wind areas I would recommend straps from blade
tip to next rotor arm so each blade tip is supported from the
two adjacent rotor arms. This provides a very rigid support and
prevents fore and aft movement.
The single support has served me well in 40-50 mph winds with
just slight fore and aft movement.
I have had poor results with wire. The stress points at sharp
bends fail quickly.
I have experienced the loss of blades many many times when i was
learning about the forces on the blades. You can drill out the
spar and put a splice pin in or run a new dowel through.
I had one turbine break loose from the rotor and spin 20 feet up
in the air like a box kite and then it settled in my side yard
30 feet away.
#Post#: 703--------------------------------------------------
Re: Seagull DIY Discussion
By: lynx wind Date: October 31, 2013, 3:12 pm
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I like your veneer blades and the only thing the dowels do is
locate the blade in position and convert 1/2 the outward pull to
torque on the rotor.
The big Gull 160 has foam blades covered in thin plastic. They
are very light. As I like to say, "they are along for the
ride".
I am sure you will be quite happy if you can replace the plastic
cord with straps. Even the metal straps used on cardboard boxes
would work very well. You might find some around a warehouse
district. I got some for free once at a metal shop in Ann
Arbor.
You might also do like I did and just go to a sheet metal shop
and ask for 6 pieces of SS. Usually they have scraps and they
just sheer it off for free if you are nice. If you want you
could even have them punch the holes so you don't have to drill.
Don't use aluminum strips because it will rip out in a few
minutes.
The way I found out about the forces on the blades was
originally I used one spar. I tried everything to keep the TE
from turning outward. I put a bracket on the outside and it
would just cave the blade in at that point. Or in some cases it
would break the bracket right out. So I went to two spars.
Problem solved. But in high winds the blades would angle
outward until the spars would snap, so I added the straps,
problem solved.
Hope this helps.
#Post#: 706--------------------------------------------------
Re: Seagull DIY Discussion
By: nessprojects Date: October 31, 2013, 5:11 pm
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Sorry to see your turbine in that condition CG. (The power of
centrifugal forces eh !).
You could tin snip some 1/2" straps from a side panel of a
microwave/washer or anything similar.
I had 1mm straps cut on a gelatine but they came out like a
banana, will cut my own next time.
#Post#: 707--------------------------------------------------
Re: Seagull DIY Discussion
By: burnit0017 Date: October 31, 2013, 5:23 pm
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Hi. any way to add a second rotor? Is that your wood wings set?
#Post#: 713--------------------------------------------------
Re: Seagull DIY Discussion
By: Otis Date: November 1, 2013, 10:42 am
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good detective work. I was gonna try similar supports, and now
probably still will.
#Post#: 715--------------------------------------------------
Re: Seagull DIY Discussion
By: lynx wind Date: November 1, 2013, 12:46 pm
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I am not pushing my ideas, just my experiences. I hope through
our ongoing experimentation and discussion we can come up with a
very affordable, efficient and rugged wind turbine.
It is important to keep the weight down because at high speeds
it can cause problems. I use foam and a thin plastic covering
on the gulls, and fiberglass on the Seagull 75. Keeping things
light helps a lot to reduce the stress. I have used strong wire
for bracing. Steel wire has stretched and broken every time. I
then tried a heavy gauge SS wire that worked but was very very
had to bend and work with. It was impossible to pull into knots
and tight bends and required heavy hardware to anchor. Finally
I realized bolting on straps was the surest and easiest.
Last night winds were very strong with 50 mph+ gusts off the
lake and my Gull Mini did fine. It is running through
Nessprojects voltage booster and the caps didn't pop
#Post#: 720--------------------------------------------------
Re: Seagull DIY Discussion
By: Otis Date: November 1, 2013, 7:07 pm
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Yeah after reducing the wing former for chloroplast, the
trailing 3/8 dowel is really tight. I didnt want to reduce the
size of spar, and already drilled 3/8 holes in rotor, so when i
made chloroplast blades i only had 1/2 of the trailing 3/8 spar
hole and the Chloroplast just pinched trailing side of the rear
spar.
My fit was a little loose, and i dont know how the rear spar
would do in high wind. Reducing may be a good idea as long as it
still does the job marcus put the second spar in to do. Have you
considered a materials change for a modified back spar?
#Post#: 723--------------------------------------------------
Re: Seagull DIY Discussion
By: nessprojects Date: November 1, 2013, 9:43 pm
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I think coroplast could be a good way to go in the construction
of the wings.
Just like to say for any UK followers that coroplast is called
CORREX FLUTED PLASTIC in the UK.
#Post#: 725--------------------------------------------------
Re: Seagull DIY Discussion
By: sut Date: November 2, 2013, 8:45 am
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Well Humm after all of this wind here 40+ gusts you would of
thought I would of seen my windmill spinning but that was not
the case (to many trees with leaves still on ) . I did find out
that the caulk I used on it was not waterproof as I thought ! .
I have taken it down to re do that with silicone, that I know
will stand up to rain. I will cut that nut in half to get my
magnets closer to coils while silicone dries . a couple of
questions when you short out the stator will it stop the
windmill completely from turning or just slow it down? When I
short it it doesn't even seem like it does anything much ! The
2nd question well more of an observation, when I had my magnets
on the plate the top side of of the plate was not even
attracting any metal, I just found this strange
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