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General control line discussion => Open Forum => Topic started by: Mike Griffin on July 03, 2013, 11:45:12 AM
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Here is something that I have wondered about in constructing a full fuselage. Assuming it is a kit..you punch out the formers and build the fuselage by whatever method you use, (ie upside down, on a jig, or whatever) when you finish you sight down the fuselage and discover that one side curves a little more than the other one. What is the cause or causes for this happening?
Thankd
Mike
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The problem is likely caused by different stresses in each sheet of balsa.........
BIG Bear
RNMM/AMM
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Not putting in structure that holds things in place while it's still in the jig!
Unless you're hand-selecting (or hand-tuning, with a sanding board) the fuselage sides after you cut them, you're never going to get this absolutely perfect. You'll probably often come close by hand-selecting the sheets from which you cut the fuselage sides, though.
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I got the problem solved at least for this fuselage. I removed formers F3 thru F7, because the bowing problem was from there back, not the crutch. I went to the very end of the tail ofthe fuselage where they come together and while sighting down the fuslage sides, I used the fingers on my right hand to slide the fuselage sides slight back and forth until the curvature in the fuselage sides matched and then I clamped the very end of the fuselage sides back together. I then reinserted the formers and glued them back and now the curve on both sides match. Remember, this is a kit cut from contest balsa and the side that was curved or bowed too much was softer balsa and I am sure that had something to do with it also....I think I got it solved.
Mike
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Purchase a C.F. Slattery fuselage jig. Problem solved.
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Even with a jig sometimes a fuse will come out slightly bowed unless you put in diagonal braces between the formers top and bottom. Go look at Doug Moon's construction pics.