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Old 05-23-2016, 08:16 AM
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MTK
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Join Date: May 2004
Location: Whippany, NJ
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Originally Posted by doxilia View Post
Matt,

please do post some pictures of your efforts. I'd be interested in seeing your adjuster design as well as hearing about your procedure for making tube sockets from 1/32" balsa and glassing.

David
David, I will.

a quick description for sockets, wing tube or stab doesn't matter. The technique is the same.

I first glass a sheet of medium 1/32" balsa with 1 ounce glass and epoxy, and let it cure. One 3" sheet is enough material for full set of sockets.

I cut rectangles wide enough for a small overlap and as long as necessary. I wet the wood well to keep it from splitting.

I wrap it around the respective tube, glass side against the tube the socket is for. Wet balsa naturally curves in the right direction making this job easy. The tube has a strip of plastic tape on it lengthwise which serves as a spacer. It only covers about 1/2" of the circumference. I then wrap a length of rubber carefully around the assembly to desired tightness, covering roughly every 1/16". Must be snug but not tight. I let this dry

once dry, I remove the rubber and carefully cut the overlap off. This isnt necessary as you can just glue the overlap down and you are good to go, but I cut it off. I then align the edges over the tape on the tube, apply some elmers and rewrap with the rubber band making sure it is snug. After the elmers dries, I remove the rubber and loosen the socket from the carbon tube. The tape is a good release. The tape is removed at this point I check the fit. I like a nice snug fit. Too tight and it would be hard to separate after a flying session; too loose and it just gets sloppy

i then reinforce the balsa with carbon or Kevlar toe, wrapping the socket with about 1/4" spacing, in both directions. Higher stress areas such as the wing or stab entry and the far end of the socket, take a few extra wraps of toe. I normally lock the toe onto the wood with nitrate dope but ca, epoxy, elmers, gorilla, what have you, all work but are heavier. There's nothing magic about carbon or Kevlar, I just have the materials on hand. Glass is fine.

Installation in the flying surface has the seam facing to the rear, the area of least stress. The installation couples the socket to the skins through sheer webs in built up wings or stabs or what I call a sub spar in foam. It must touch the socket and the skin, forming an "I" beam structure. I usually use 1/16" or 3/32" medium balsa for sub spars. These extend beyond the end of the socket by a couple inches removing the stress riser. I don't like the more popular practice of supporting the socket with sub ribs at the ends only.

Hope that's clear