To those of you who have decided to rib stitch your wings, did you still glue the fabric to the rib cap strips or did you let it float, only gluing to the leading and trailing edges, like a certificated fabric covered plane?
To those of you who have decided to rib stitch your wings, did you still glue the fabric to the rib cap strips or did you let it float, only gluing to the leading and trailing edges, like a certificated fabric covered plane?
I followed the SS7 build manual and precoated the rib cap strips with diluted Polytak cement, then covered with fabric, then shrunk with heat, then brushed on MEK to activate the cement on the cap strips, then rib stitched. On the bottom undercambered part I only shrunk part way with heat and then activated the cement and let it dry with weight on it; then finished shrinking and rib stitched.
I think it is important to let it float while shrinking, then glue it down after it is in its final position and tension.
Jim Ott
Portland, OR
Kitfox SS7 flying
Rotax 912ULS
I basically did the same thing with Oratex also - applied glue to the capstrips, but didn't activate it with heat & pressure until after the initial shrink.
John Evens
Arvada, CO
Kitfox SS7 N27JE
EAA Lifetime
Chap. 43 honorary Lifetime
With all the rain up here, I actually started recovering the second wing for my Avid yesterday. I reviewed the Poly Fibre manual a bit, and in the section near the back of the book that deals with undercambered wings, it says to not glue the top of the wing if you are going to ribstich. Of course you had to glue the bottom to keep the fabric from ballooning away from the rib when you shrink the fabric. I would imagine not glueing the top of the ribs would help the fabric to have a more even stretch overall. I have to admit though, as long as I already had the two coats of poly tac brushed on the top of the wing ribs, I glued it down. (belt and suspenders) Jim Chuk
Thanks for the replies, gents.
I poly brushed the bare cap strips top and bottom but did not poly tack them.
Tom Jones
Classic 4 builder