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orion

R.I.P.
Joined
Mar 2, 2003
Messages
5,800
Location
Western Washington
The downside to this is that you pre stress the skin. It won't have near the strength that it would otherwise. I was pretty excited when I first heard about it but Orion's comments have made me somewhat leery of using it.
Personally, as Will indicated, I don't really like this approach but with additional analysis and reinforcement, I wouldn't necessarily rule it out out right.
 

flyoz

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Joined
Jul 30, 2008
Messages
149
Location
Near Sydney
I have made some test pieces using 10mm Divinicell . I "slotted " the material 8mm apart and half the depth with a hacksaw bade (i made a simple jig to limit the depth of cut ) . Two layers of CF cloth on the outside - its strong . I filled the slots with epoxy and micro balloons , bent the inner surface and glassed it . When it had cured i glassed the outside. The photo shows a 65 mm Dia bend about as small as i could get it . Bends very well and repeatably but only in one plane - see Jpg
Flyoz
 

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flyoz

Well-Known Member
Joined
Jul 30, 2008
Messages
149
Location
Near Sydney
I found it very difficult to maintain the thickness and control the position of the bend with heat - this method is actually quite simple and the bend is uniform and the bend start and stop position is definative . The other important issue is springback - with this method there is virtually no springback and glassing the inside first and then the outside means one layer is not constantly under tension . A clean 65mm Dia bend with 10mm divinicell is actually quite hard to achieve . The only drawback is that the part can only be bent in one plane .
Flyoz
 

NickH

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Dec 26, 2010
Messages
101
Location
Portland, OR
This looks great. I think if I were starting over I'd try it this way, and do the whole fuselage in 1/2" foam.
 

Vector

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Joined
Dec 4, 2010
Messages
345
Location
Pacific
Did anyone laying divinycell as strips(stripping) have issues with keeping the material over compound curves? After laying 2 layers of FB, I intend to apply epoxy and lay strips of divinycell 1/2" then covering the foam with 2 additional layer of cloth to finish it up. Any thoughts?
 

BGStewart

Member
Joined
Jul 13, 2011
Messages
7
Location
Tracy, California
I bought a sheet of Airex to test. It came scored and perforated. If using the scored and perforated Airex, what surface prep is recommended? I also bought a sheet of Divinycell to test.

Bryon
 

hogheadv2

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Joined
Feb 7, 2010
Messages
127
Location
Booger finger of Michigan
Has anyone tried a metal shed solar headed for a large oven? Maybe start with several large rocks heated in a fire, and continue with the afternoon sun?
Just turning my brain looose to fit a wing ?!?!
 

Vigilant1

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Jan 24, 2011
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6,239
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US
Has anyone tried a metal shed solar headed for a large oven? Maybe start with several large rocks heated in a fire, and continue with the afternoon sun?
Temperature control is important--the parts can be ruined if overheated. IF the sun is used, then it's best to have some type of thermostatically controlled fan to pump in cooling air if needed.
-- Folks have used black plastic draped over the parts (with an airspace and a fan to circulate the air), and placed in the summer sun. This can work, but sometimes, even with the fan, the side of the part exposed to the radiant heat from the plastic gets quite a bit warmer than the other (shaded) side.

-- Usually, just constructing a simple "oven" out of cheap construction insulation and using a heater with a fan is the best approach. It works any time of day/year, the heat is even, and it is probably easier than cleaning out the metal shed to make room for the wing!
 

Tom Nalevanko

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Joined
Oct 10, 2007
Messages
1,340
Location
Alpine, WY
Companies at Mojave, home of Scaled Composites, regularly use metal shipping containers exposed to the desert sun as ovens.
 

wsimpso1

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Oct 18, 2003
Messages
7,961
Location
Saline Michigan
OK, now I understand what you want... Jan does not appear to have polystyrene flotation billet on his list.
 
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