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fuselage fabrication

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Foilsnowsurf
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Re: fuselage fabrication

Postby Foilsnowsurf » Tue Jan 23, 2018 2:52 am

Wow, Airsail! Genius idea using the carbon sleeve over a dowel.
How many sleeve layers would you need between the front foil and the mast (or slightly behind), and how many could be reduced for the trailing part of the fuselage? Any need to add longitudinal carbon in addition to the 45 degree wrap created by the sleeve layers?
Off topic slightly, anyone have a usa source for 316 ss 8mm inserts for the fuselage? Or better yet titanium?
Hey thanks! Robert

Foilsnowsurf
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Re: fuselage fabrication

Postby Foilsnowsurf » Tue Jan 23, 2018 3:13 am

Great idea, how many layers of sleeve between the foil and mast needed?

Anyone have a usa source of 8mm inserts for the dowel? Stainless or titanium.

Ash or hickory a good choice?

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downunder
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Re: fuselage fabrication

Postby downunder » Tue Jan 23, 2018 3:38 am

Ummm,

the tube has definitely a release agent inside. If there isn't this would not just peel off:

Image

Also, the tube is not a hydrodynamic shape. I mean, all fuselages are at least a bit shaped in that way.

When you drill a tube for M6 inserts, the drilled hole is not round, it's slightly oval on top. The compression when bolted is immense and the hole started cracking on sides. With added torsion that would break in no time, if not wrapped for torsion heaps.

How much torsion is on the fuselage? :naughty:

airsail:

from my model making experience, when wrapping a tube, the carbon must be tensioned. Have a look how sail masts are built. With this sleeve, we can't tension it since it expands by the design. Only epoxy is keeping it not to expand. No go.

fsf:
Plenty of 316 8mm around. But why 8mm? Is this for the mast?

I used ash, but it's quite soft wood. It turns perfectly in the lathe tho, as any soft wood. However, resorted to hard wood since heaps better for mast/fuse connection. At least 5 layers around the mast in all possible angles.

Shaping the wing slot with a chisel takes, ummm, 15mins? With no previous experience.

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Re: fuselage fabrication

Postby rynhardt » Tue Jan 23, 2018 8:43 am

downunder wrote:
Tue Jan 23, 2018 3:38 am

from my model making experience, when wrapping a tube, the carbon must be tensioned. Have a look how sail masts are built. With this sleeve, we can't tension it since it expands by the design. Only epoxy is keeping it not to expand. No go.
I beg to differ.. the braided sleeve's tows run in exactly the same path as a wrapped tow would, i.e. a spiral around the tube. The warp will go clockwise and the weft anticlockwise.
The only reason it expands is because the tows are still free to move relative to each other when no resin is present.
If you were to wrap a tube with just tows, and not add resin or fix the ends, then it would behave the same as the braid without resin.

Add resin and the picture changes dramatically.

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downunder
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Re: fuselage fabrication

Postby downunder » Tue Jan 23, 2018 9:36 am

Uhmm,

try to wrap a tube with a light carbon sleeve (or a FG by that matter), you'll see what a pain that is. You would need exact measurement to cover with a sleeve ie:

http://www.sollercomposites.com/light-sleeves-sock.html

To be more precise, the fibers are not close to each other when the sleeve is expanded. This creates a void which just looks ugly AND it's stress raiser. When I said "the carbon must be tensioned" this is exactly to have it super close to other fibers, and that is only by slight tension (or compression onto the surface - but we can't do that on a tube). Impossible to tension a sleeve, absolutely impossible.


I mean, we really need to put ourself's in someones shoes, a wannabe DIY builder.

That's the problem. A pro shop can do whatewer, but not everyone can.

Thoughts? I mean I have a feeling you are picking on me recently :)

Here, three years ago:

On 1/29/15, jon.soller@sollercomposites.com
<jon.soller@sollercomposites.com> wrote:
Hi,

Yes, but sleeves are not damaged by rolling them up like a flat fabric is.
So there is not advantage to shipping sleeves without folding.

We ship to AU every day.

Best Regards,

Jon Soller
Soller Composites, LLC
55 Industrial Park Dr Unit 3
Franklin, NH 03235
www.sollercomposites.com
1 603 671 7016
FAX 1 815 642 9593

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Re: fuselage fabrication

Postby airsail » Tue Jan 23, 2018 10:11 am

I’ve built 2 fuselages this way though I used foam rather than dowel. Dowel would provide additional strength and I would use this next time as it is easier to bond the nuts into it. So far no breakages and they have been given a hard life.
You can also build up the area where the wings attach prior to sleeving, the sleeve will follow the contours. Don’t vac bag it, you will end up with creases.
I ran 3 full layers of carbon with extra layers from just aft of the mast attach area to the front. The point just forward of the mast is the highest stressed area.
The mast/fuselage attachment is critical, just bolting it on doesn’t work, too much flex and the foil feels unstable. After much experimenting I gave up, bolted and glued the mast to the fuselage then glassed over it.
Rear stab needs to be adjustable but the forward wing can be solid. The less joints the better the ride, and to be honest regarding wings, almost anything works.

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Re: fuselage fabrication

Postby rynhardt » Tue Jan 23, 2018 12:12 pm

downunder wrote:
Tue Jan 23, 2018 9:36 am
Uhmm,

try to wrap a tube with a light carbon sleeve (or a FG by that matter), you'll see what a pain that is. You would need exact measurement to cover with a sleeve ie:

http://www.sollercomposites.com/light-sleeves-sock.html

To be more precise, the fibers are not close to each other when the sleeve is expanded. This creates a void which just looks ugly AND it's stress raiser. When I said "the carbon must be tensioned" this is exactly to have it super close to other fibers, and that is only by slight tension (or compression onto the surface - but we can't do that on a tube). Impossible to tension a sleeve, absolutely impossible.


I mean, we really need to put ourself's in someones shoes, a wannabe DIY builder.

That's the problem. A pro shop can do whatewer, but not everyone can.

Thoughts? I mean I have a feeling you are picking on me recently :)

Sorry dude, not intentional. Unfortunately I rarely post when I agree, so you only see when I disagree :-?

I thought the carbon braid was a good option. One braid size fits a range of tube diameters, and it's pretty easy to just slip over a tube and you're done.
The warp and weft of the braid will run approx 45/-45 so is great for torsional loads, but even at 45 deg will probably be fine for any longitudinal bending along 0 deg, seeing as the tube is pretty thick.
As for the perceived issue with the fibers not being close to each other, I don't understand why that would be a requirement?
And I am a wannabe DIY builder, for what it's worth.

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downunder
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Re: fuselage fabrication

Postby downunder » Tue Jan 23, 2018 2:48 pm

Airsail,

3 layers of 200g cloth is less than 0.75 mm.

The carbon tube with 1mm wall 22 mm diameter is flexy as when I stand on it. And that is biax. Sleeved carbon with the same wall would be even more flexy.

For sure, bigger the diameter - better. When I stand on 30mm tube it does not bend that I can feel. Thats only 8mm diff in diameter.

Hence, when you say that u wrapped a fuselage, what is the diameter?

ry,

No worries man. My WS mast is wrapped quite near to 90 degrees with a tow carbon on outside. It is so precise that almost impossible to see where the join is. Thats my base line.

Can we agree that if sleeved carbon is any good, the WS masts would be built that way?

No idea if they are. Never seen one tho.

https://m.youtube.com/watch?v=lE1T81Jx3aA

What I see on this is tensioned carbon. If not, it would not be that perfectly aligned.

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Re: fuselage fabrication

Postby tmcfarla » Tue Jan 23, 2018 5:19 pm

Foilsnowsurf wrote:
Tue Jan 23, 2018 3:13 am

Anyone have a usa source of 8mm inserts for the dowel? Stainless or titanium.

Ash or hickory a good choice?
Search for “titanium flange nuts” on eBay. There are a bunch of sellers. They are made for bikes and are a bit narrower than snowboard/kiteboard inserts, but should be workable.

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Re: fuselage fabrication

Postby tahoedirk » Tue Jan 23, 2018 6:29 pm

1516728145675.jpg
Here is a slightly complicated mold that is still quite versatile.
20180123_091759.jpg
My new xl fuse is still a little rough
Yes, now we're talking. You show me yours and I'll show you mine!


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