I RECENTLY CRASHED ON LAUNCH(I TRIED TO REPAIR A BROKEN STYLUS ANTENNA MYSELF...MISTAKE!).
THE WING PULLED THE WOODEN BLOCK OUT OF THE PYLON AND THE PYLON CUT A V SHAPE SLIT IN THE UNDESIDE OF THE RIGHT FLAP. THE TOP SKIN OF THE FLAP WAS SEPERATED FROM THE FOAM AT THE HINGE LINE FOR 1" INTO THE FLAP.
I HAVE NEVER REPAIRED A BAG WING WITH THIS TYPE DAMAGE ANY SUGGESTIONS WOULD BE APPRECIATED.
For the delamination you just need to work epoxy in between the skin and foam. Use a single edge razor blade or a scrap of bagging mylar for that. Then weight the flap down flat while the epoxy cures.
If you have a gouge or groove in the underside of the flap, just fill it with an epoxy/filler mix. Let that cure, sand it smooth and put a light fiberglass patch over it. You can then sand the fiberglass patch smooth after it cures.
A picture might help us get a better idea of the damage.
Now some more general comments about bagged wing repairs:
Use thin laminating epoxy such as Z-poxy or West Systems. I always recomend West Systems 410 filler for for all sorts of filling/repairing. You can buy it at CST.
Always weight the part down when re-attaching skin or if the part being repaired needs to be returned to its proper alignment or shape. In the case of a wing skin you would put it in the beds while weighting it. In the case of just the flap it might be easier to just weight it to a flat surface. Use something like wax paper between the part and the beds to be sure you don't attach the wing/part to anything it shouldn't be attached to. Be carefull not to gum up the hinge with excess epoxy, use paper towels to wipe away excess before it cures.
When putting a fiberglass patch on the underside (unpainted) surface you just need to rough up the area with sandpaper to remove any wax residue left from the bagging process first. On the top surface you would probably want to remove the paint first. I do that mostly with a Dremel 1/2" diameter sanding drum mounted in a flex shaft. The flex shaft allows the sanding drum to lie flat against the surface of the wing. I then finish the job of paint removal with hand held sand paper.
You can make fiberglass repairs as smooth as you want by just sanding it after it cures. Then rub epoxy into it, let that cure and sand it again. Repeat as often as you like. Don't sand the last application of epoxy and it will retain its glossy apearance. The final "skim coat" of epoxy will only take a drop or so per few square inches of surface. It only takes two or three applications of epoxy to achieve this assuming that the glass patch was relatively smooth and flat when first applied. The easiest way to attach a fiberglass patch in the first place is usually to spray the glass very lightly with 3M77 and then put the glass patch in place on the wing. Then go ahead and rub epoxy into it. The fiberglass patch is applied after the surface has been repaired to the correct shape and all dents and gouges are filled with the epoxy/410 mix.
If you use West Systems 105 epoxy and 205 (fast) hardener you can do about three applications of epoxy in one day letting it cure at room temperature. You can cure the stuff in less than hour when doing parts that can be heated (usually fuselage parts).
REPAIRING AEGEA WING
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Posted - 07/19/2004 : 12:04:14 PM
