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Building Tips and technical articles. => Building techniques => Topic started by: rich gorrill on July 03, 2013, 01:23:04 PM
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I have tried everything under the sun to straighten this fuselage. It can't be done. After soaking with ammonia water, steaming and weighting, next day it is crooked again. I give up, i'll just cut a new one and be done with it. Thanks for the help.
Rich
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Was this a profile fuselage? Which way is it warped?
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For a profile fues, I like to laminate two or three layers of thinner balsa together with slow epoxy. If you wet both surfaces with adhesive and scrape off almost all the epoxy then clamp it to a straight surface until it cures you will have a very straight and very strong piece of wood to cut your part from.
Don
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I had a warped Ringmaster profile (surprise, surprise). I twisted it out and applied fiberglass wing seam tape to the once longer side. Set up fine but did add considerable weight. I think if I used carbon fiber and finishing resin it would be fine.
Joe
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I probably should have said this profile fuselage was bowed, not warped. I tried one more thing and I think it worked. I soaked the fuse. in ammonia wated put a piece of 1/8 balsa in the middel and weighted the ends and back bent it. I let it dry 24 hrs. and it seems like the bow is gone. I don't know if this will work everytime, but it seemed to work this time. Hope it stays this way and the bow doesn't return. Either way Sig already sent me a new fuselage to replace this one and it was perfect.
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I probably should have said this profile fuselage was bowed, not warped. I tried one more thing and I think it worked. I soaked the fuse. in ammonia wated put a piece of 1/8 balsa in the middel and weighted the ends and back bent it. I let it dry 24 hrs. and it seems like the bow is gone. I don't know if this will work everytime, but it seemed to work this time. Hope it stays this way and the bow doesn't return. Either way Sig already sent me a new fuselage to replace this one and it was perfect.
Rich, take that now-straight fuselage, and put it someplace flat. Let it sit there for at least a month. If it's still flat, then you've fixed the problem. If it's not, then use pieces of it wherever you need a little block.
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I have soaked bowed pieces of balsa in ammonia until thoroughly soaked and then let dry. Stayed straight after removing all the weights. I believe the ammonia breaks down the cells of the wood. But the straightest and stiffest fuse I have for profile is the Primary Force fuse from Mike Pratt. Used Gorilla Glue with lots of clamps while eye balling it. It was laser cut 1/4 balsa sheets laminated to make 1/2 inch fuse. One of the best flying planes in my arsenal.
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My current kit's fuse is slightly bowed. I tried wetting with Windex and counter bowing it with weight, but it didn't change. It's such a small bow I could probably sand it out with enough elbow grease. It's bowed in the "good" direction if there is such a thing. I might get a new piece when it comes time to start working with the fuse. Or use it and leave off the thrust wedges.
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In reality I have flown a lot of profiles with the fuselage bowed.