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Old Sep 17, 2012, 11:26 PM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
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First layup! Reality check.

So I'm finally getting into vacuum bagging. I've been fiberglassing my wings without vacuum for a while, but now taking the plunge into serious composite work. My plans are to initially keep it small and heavy... a sloper. A 36" sloper can keep cloth costs down, and I can put ballast into bad, epoxy-saturated wings instead of removable ballast in the fuse .

3 layers of 5.8oz glass, 2 on bias, one not.

And then a kevlar & glass fuse that I already have lying around. This is gonna be a basher.

Any comments on my build strategy? Thanks.
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Last edited by acetech09; Sep 20, 2012 at 05:58 PM.
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Old Sep 18, 2012, 07:38 AM
Father of Fr3aK, DLG Pilot
tom43004's Avatar
USA, OH, Worthington
Joined May 2002
6,592 Posts
Buy 3x the materials you need to get your first part done. I seldom if ever get a usable part on the first pull... but I learn alot. Make a checklist before you mix epoxy and have it ready so you don't forget anything, and you do things in the right order. Go through the checklist at least twice before you mix epoxy.
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Old Sep 18, 2012, 09:04 AM
Just fly it!
wyowindworks's Avatar
Cody, WY
Joined Nov 2007
6,915 Posts
That sounds pretty light for a sloper. My production bagged sloper wings that were 50" or less used 2 layers of 2.3 ounce glass and 6 ounce carbon.
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Old Sep 18, 2012, 10:17 AM
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Australia
Joined May 2010
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Would recommend you practice your leading edge technique prior to giving it a go on a good core. It took me a few go's to get it right, and Don't be shy on putting on the 3M spray...... Of course I could be just a little slow

Cheers,
.adrian
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Old Sep 18, 2012, 10:17 AM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
1,505 Posts
Just realized I made a typo... 2.6oz glass instead of .6... .6 is a bit light ain't it. Fixed the OP. Should I go with a heavier uni carbon still?
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Old Sep 18, 2012, 10:18 AM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
1,505 Posts
Quote:
Originally Posted by al010964 View Post
Would recommend you practice your leading edge technique prior to giving it a go on a good core. It took me a few go's to get it right, and Don't be shy on putting on the 3M spray...... Of course I could be just a little slow

Cheers,
.adrian
Hence the reason for cheap small 36" glass cores that will only cost me about $40 if I screw up
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Old Sep 18, 2012, 04:58 PM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
3,177 Posts
Hey, if I were building my first bagged wing, I would use no carbon or kevlar, just use 2 or 3 layers of cheap 6oz glass, cut on a bias running the whole length of the wing, dont need to worry about a spar. For the leading edge I would trim the front off the cores and put on a hard wood leading edge after bagging. I tried for ages to get great leading edges when bagging, and even when you get them right they are never going to be as dint resistant as wood is. Keep it simple and you cant go wrong (too much anyway....)
Good luck- its frustrating but highly addictive!
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Old Sep 18, 2012, 05:10 PM
Just fly it!
wyowindworks's Avatar
Cody, WY
Joined Nov 2007
6,915 Posts
If you put all the layers on +/-45 without a spar the wing will probably warp along its length. I would put one of those layers on 0/90. The top and bottom should be an exact mirror of each other. The bias cut material should be a balanced fabric. If it's not then you should flip one of the two bias cuts so the two together will function as a single bias cut layer.
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Old Sep 20, 2012, 01:03 PM
Composites guy
North OC, Ca.
Joined Jun 2005
1,172 Posts
Start cheap and simple-
Glass( 4-6 oz on a bias) skinned wing with some carbon tow in grooves in the foam to act like a spar. Work on waxing and painting the mylars and other issues.
Make a beater for the first one and learn. Finish that wing and learn about the other issues- hinging etc.

Get that right before the $$ materials go wrong.

my $.01
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Old Sep 20, 2012, 05:59 PM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
1,505 Posts
Is there a different spar tactic when it comes to bagged wings than normal? I've built quite a few non-composite planes, and have experience when it comes to laying in cores flush with the surface.
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Old Sep 21, 2012, 11:13 AM
Composites guy
North OC, Ca.
Joined Jun 2005
1,172 Posts
Ace-

Not sure what defines"normal" but on a cored wing, there is an option to sand a groove in the core(top and bottom) and fill with carbon tow to act as a spar. After that cures, cut a vertical slot nect to the tow channel and add a plywood shear web out spanwise.
Fill and sand flush with the core and then move to bagging the wing.
Scott
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Old Sep 24, 2012, 06:22 PM
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Joined Nov 2004
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Do you need the plywood shear between the 2 carbon spars, wouldn't the foam serve this purpose
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Old Sep 25, 2012, 03:57 AM
Arrarrar!
josh18's Avatar
Australia, NSW, Wagga Wagga
Joined Jan 2010
3,177 Posts
You dont need any spar at all I reckon, not on a 36" wing. If one of the layers of cloth is layed at 0/90 degrees that acts as a big spar cap and the foam acts as a big shear web.
IMO YMMV etc, etc.....
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Old Sep 27, 2012, 10:11 PM
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United States, MA, Waltham
Joined Dec 2001
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If you want a really inexpensive material to mess around with, try kraft paper. Paint the epoxy on both sides, wait a few minutes, scrape the excess with an expired credit card, and bag it on. Surprisingly nice stuff on the one set of wings I made this way. I screwed up the trailing edge and it turned out the 60 lb paper was a bit heavy for an hlg, but they came out nice otherwise.
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Old Sep 28, 2012, 11:32 AM
Slopeaholic
Hutch's Avatar
Roseville, California, United States
Joined Mar 2001
3,098 Posts
Try not to overthink it too much Ace. You'll find when it all shakes out bagging is easier then sheeting with wood. It is just more unforgiving of poor planning. The bigger the wing, the more efficient each step needs to be. Your 36" wing should be a piece of cake.

Final thing that I didn't see you mention...You'll want to have a layer of light glass that goes down on your mylars first for a finish layer. Your life will be much easier when it comes to finishing later!

-hutch
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