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Foam wing repair

Old 12-05-2016, 08:44 PM
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Jetset
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Default Foam wing repair

Need some advice on a repair. It's a sheeted foam wing that has been glassed. It had a bit of a hard landing and cracked the top skin. Looks like the gear plate twisted a bit plus it was forced up as well.
I have a rough idea what I think I should but would like an expert's opinion here as well
Retract is no biggie as I have another one.
What would you do?
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Last edited by Jetset; 12-06-2016 at 12:45 PM. Reason: typo
Old 12-06-2016, 09:02 AM
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mikes68charger
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Me, I would cut the top balsa skin off in a huge rectangle, around the crack, at least 3in on each side of the crack, cut it out with a cut off wheel, not very deep just the balsa. Once off, put epoxy in the crack and make sure the wing is installed in the jet when you do this, so there in no chance of changing thing shape.

once cured, take a small block with 36 grit sand paper, and sand the foam down about 1-2mm, then put down 1 to 2 layers of 6oz glass cloth (stuff from Lowes), make it level to the rest of the foam, while still wet (the glass needs to be wet with finishing epoxy, a box or Z poxy) then replace the balsa top skin with new balsa, make it as tight as possible, then take your drill, with a sanding/grinding disk 2in grind some of the glass off about 1/2in past were you cut the balsa out (do this before fiberglass), then once you put the balsa down, (it will be glued down with the finish epozy) Then top the balsa with 1/2 oz cloth with the z poxy, if you do all the prep work you should beable to do the all the fiberglass work within 10min.

The retract area, that sucks, either epoxy back the foam, and add a carbon fiber rod from broken part to the good part of the wing.
Old 05-26-2021, 12:31 PM
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Biggie dickus
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Originally Posted by mikes68charger View Post
Me, I would cut the top balsa skin off in a huge rectangle, around the crack, at least 3in on each side of the crack, cut it out with a cut off wheel, not very deep just the balsa. Once off, put epoxy in the crack and make sure the wing is installed in the jet when you do this, so there in no chance of changing thing shape.

once cured, take a small block with 36 grit sand paper, and sand the foam down about 1-2mm, then put down 1 to 2 layers of 6oz glass cloth (stuff from Lowes), make it level to the rest of the foam, while still wet (the glass needs to be wet with finishing epoxy, a box or Z poxy) then replace the balsa top skin with new balsa, make it as tight as possible, then take your drill, with a sanding/grinding disk 2in grind some of the glass off about 1/2in past were you cut the balsa out (do this before fiberglass), then once you put the balsa down, (it will be glued down with the finish epozy) Then top the balsa with 1/2 oz cloth with the z poxy, if you do all the prep work you should beable to do the all the fiberglass work within 10min.

The retract area, that sucks, either epoxy back the foam, and add a carbon fiber rod from broken part to the good part of the wing.

hi I tried this but stripping the balsa resulted in pulling chunks of foam out ( Jim fix viggen very thin wing) I filled the worst with lightweight filler to keep the weight down using less resin and then glassed the foam. Because it's not totally smooth I will have to balsa when the glass has cured with polyurethane glue the sort that expands with water. Thoughts?

Old 05-26-2021, 02:35 PM
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GREG DOE
 
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I just repaired a Quickie 500 wing with two cracks from the leading edge to the aileron. The cracks were about 8 in. long. I got a 12ml. hypodermic syringe from Tractor Supply for less then a dollar. I already had a large needle. I drilled small holes along the crack at about 3/8" intervals. I think I ended up with 33 holes? I injected West Systems epoxy, but probably any good laminating or even finishing resin would be fine. As I progressed up the crack, resin would be forced out of the previous holes, or the next hole. I then glassed the cracks with 2 strips of 3.7 oz. cloth, that extended about 1" each side of the crack, It hasn't been flown yet, but I have no doubt that it will not break. Weight gain for the repair was about 1/3 oz. The wheel well adds a challenge. I would probably reinforce that damage with carbon fiber cloth.

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