wing tip install ?

[phintz]

instructions say on one page use 1/8 by 1/4 flush rivets, on the other page with the picture diagram it says use epoxy also. Since the fabric rolls over the end cap and around the side does it make since to expoxy also or should I just rivet. Whats everyones thoughts?

[Dave S]

Hi Patrick,

Although it certainly is the builder's choice to employ alternate assembly methods and procedures as they see fit and appropriate; certain points in the instructions are the result of the experience and familiarity with issues by people who have designed and built many airplanes of this design.

I can't claim to know for sure exactly what all the reasons are for this procedure; however, I decided the instructions were probably that way for good reasons.

Considering the wood ribs and all the holes that are being drilled in the edge to fasten the aluminum strip; it is a place where moisture, either condensation or rain/wash water could soak/seep into the wood between the strip, rivets and raw wood of the drill holes if they are not sealed somehow...a prime spot for rot to get started on the wood and corrosion on the rivets. Close contact areas can stay wet for an awful long time after the outside has dried off.

A good job of bonding helps seal up the rivet holes from moisture; and, makes the connection between the strip and the rib stronger than rivets alone. The rivet tops are covered by an additional finishing tape and sealed pretty well; but, the bottoms/inside would be pretty well unprotected unless measures to seal them up are taken.

Another thought on the situation is what would be gained by not bonding the strip?

Sincerely,

Dave S

KF 7 Trigear - Flying
912ULS Warp Drive
St Paul, MN

[HighWing]

I've been thinking about this question and my response might not be pertinent to the specifics but.... My tips are of the Horner variety. They are not removable and the aluminium strips were riveted and Hysoled in place. I liked Dave's question about possible downsides to either technique. One that comes to mind if the strip is glued as well as riveted is the challenges that might be found removing the original fabric if it was ever necessary to recover the wing. You could also seal the wood by dipping the rivet in epox

One more thought on the Horner tips. I pisitioned them and drilled and clecoed in place. Then did a rough cut 1/8" oversized then took the cut scrap and after scuffing both sides and trimming it to about 1/2" width and to length, glued in a double layer between top and bottom skins to give the trailing edge the same thickness as the aluminum trailing edge. Clamp between two pieces of angle that extend a foot or so onto tha aluminum until cured. Then a final trim with some micro or Bondo where necessary, sand and paint. The trailing edge will remain straight.
Lowell

[henrysamson]

I had the same questions and I used solid flush rivets on my Model IV to attach the aluminum strips that have the nut plates. I did not also use epoxy as I was concerned about having to remove them if I needed to recover the wing as the strips would be glued to the fabric. I did use epoxy varnish in all holes I drilled through wood before I riveted as I saw the area as a moisture trap.

My plane should be flying soon so I guess if the tips blow off I should have used epoxy also!

[n85ae]

Just rivet the strips and move on. You'll paint over it anyway, and likely your
plane will die of waxitis (being waxed to death in a hangar) long before
the slightest hint of rot or corrosion's sets in. It's not complicated :)

Regards,
Jeff