Wingtip Confusion

[taff]

When I was building my IV, I riveted aluminum strips to the outboard rib and installed nutplates to these strips.
I used screws to fasten the wing tips.
These are the only photos I have during the wing tip attach.
I don't think it matters much as the the width of the strip, 1.5"? As to the gauge, as long as it can securely hold the nutplates and your able to countersink the nutplate rivets.

[n85ae]

I riveted aluminum strips into my end ribs and put in nutplates. My wingtips are drilled and attached with
screws to the strips. The sloppy mess with the glass in the wingtip is typical of all the parts I got from
Skystar when I built mine. I would never try to bond to the polyester resin with 3M 2216 or Hysol, because
I don't think it would hold.

Jeff

[Eric Page]

When I was building my IV, I riveted aluminum strips to the outboard rib and installed nutplates to these strips.
I used screws to fasten the wing tips.

I riveted aluminum strips into my end ribs and put in nutplates. My wingtips are drilled and attached with
screws to the strips.

Yes, both the S5 and S7 manuals mention this as an option, and I think the S7 manual pitches a kit of parts to do it. I can't imagine what the kit contains other than nutplates, flush rivets, screws and maybe countersunk washers.

I'm planning to make mine removable. I don't expect to remove them, but I'll definitely need to if I glue and rivet them!

I don't think it matters much as the the width of the strip, 1.5"? As to the gauge, as long as it can securely hold the nutplates and your able to countersink the nutplate rivets.

Good point. I'm assuming the strips I found are them (and they're 1" x 0.050"), but I just don't understand how the holes don't line up unless they were drilled separately from the cap strips!

The sloppy mess with the glass in the wingtip is typical of all the parts I got from Skystar when I built mine. I would never try to bond to the polyester resin with 3M 2216 or Hysol, because I don't think it would hold.

Hmm, that's interesting. Oddly, the bond failure in my wing tips is at the aluminum, not the fiberglass/resin. I suppose it's not critical that I achieve a structural bond on those strips, as they're really only there as spacers anyway.

If the structural adhesives we use aren't reliable on polyester resin, then I presume we have to use more resin to close the tail of the tips.

[jrevens]

... I would never try to bond to the polyester resin with 3M 2216 or Hysol, because
I don't think it would hold. Jeff

If the surfaces are cleaned & prepared properly epoxy will make a stronger, some would say better joint than polyester resin. The issue that can be encountered is that wax is sometimes added to resin, which rises to the surface and helps facilitate the cure with polyester resins. It is also sometimes applied afterwards for the same reason. If that is the case it has to be removed before epoxy or additional polyester resin will bond properly. A good acetone wipe, followed by sanding and another wipe is effective. Epoxy is the best, strength wise, for repairing fiberglass structures whether they are made with polyester resin or epoxy resin.

[taff]

This is how I done mine.
First dry fit the aluminum strip to the cap strip before fabric covering and drill the rivet holes, Countersink the cap strip for the rivet that will be installed later.
Apply the fabric and tuck it /glue it under the cap strip. Heat iron and shrink as normal.

Install the aluminum strips. No need for "bonding" you will be bonding to the fabric = no structural strength.
Rivet the strips in place with countersunk rivets. Use soft rivets or you may be damaging the rib cap strip.
When everything is secure fit the wing tip and drill pilot holes for where the Rivnut is going to be riveted. You need a tool for aligning the holes for the Rivnut.

Use countersink washers if you want to use countersink screws, or pan head screws.

Use a little beeswax on the threads of the screws. Makes easier removal from rivnut.

[Eric Page]

Yeah, I suppose wrapping the fabric makes sense to prevent it from lifting at the end of the wing, and given the number of rivets holding the attachment strip in place, the adhesive is probably superfluous anyway.

Thanks, everyone.