couple of sessions working on the wing root fairings. then started the wingtips today.

On the surface, the wing root fairings look dirt simple. They line up nicely with prepunched holes aft of the main spar, then you wrap them around the leading edge and pick up a couple of prepunched holes underneath near the main spar. You then match drill the holes in the fairing to the inboard flange of the tank.

While I had the wings on, I match drilled all the prepunched holes on the upper side aft of the spar, but due to the fuselage sitting on the fuse cart I wasn't able to get to the ones on the other end, i.e. bottom side by the spar. Based on that, I elected to not trim the gap to fit up to the fuselage side until later.

Now that the wings were off, I though that it would probably be a good time to match drill and dimple tank inner flange, but when I tried to wrap the fairing around the leading edge of the right wing it appeared to be too short by about 1/2 a hole by the time I got to the lower end.

Spoiler alert; I messed around with this stupid thing for several hours before I got it to fit right with all the holes lining up and dimpled. I also had to drive down to the yard store and get a #8 dimple die set because somehow I don't seem to have one.

The fairings ship flat and you are left to your own devices to bend them around the leading edge. I surmised that just forming it around the leading edge by hand was allowing it to spring back and preventing me from getting a super tight fit, so I spent some time experimenting and ended up rolling the leading edge bend around a 2" pvc pipe. Many cycles of mark/bend/on/re-mark/off/re-bend.

All of this finesse allowed me to pick up most of the extra length I needed for the lower holes to line up, but I did end up with a slightly oblong hole in the fairing oh the very aft lower end. This is a dimpled hole for a #8 screw, so there is a pretty big dimple there close to the edge, but the dimple doesn't run all the way to the edge of the piece, just not as perfect as I would like. I'll keep an eye on it when it comes off for the annual inspection and if it looks like it's working I can always make another fairing.

In retrospect, I think that there is enough variation when the tanks are built that this fairing could likely not fit well. It would be nice if Vans cut it a little long and left the section that fits up with the bottom of the wing un-piloted, not just the part that covers the tank inboard flange. That way you could match drill as needed and trim the end to fit.

Anyway, once I understood what I was dealing with, I was able to account for it when I upsized the pilot holes on the fairing for the other wing. Finish work on that fairing was knocked out in about an hour.

Part of this whole process was to match drill for nutplates in the inboard flange of the tanks, Then dimple and install nutplates. Lot's of attention to detail is needed in this whole process because where the wing walk is you countersink and install K1000-8 nutplates. On the tank flange, you dimple and use K1100-8 dimpled nutplates. It would be easy to get the two confused and end up with the wrong combo.

After the fuse fairings were put to bed, I turned my attention to the wingtips. vans says that you can either pop rivet these on or use nutplates. There is a 3rd option that appeared on VAF about 10 years ago and has been used successfully by a lot of people at this point, which is to attach them with piano hinges similar to the was vans recommends you attach the cowling.

While I like the idea of piano hinges for their simplicity and the ability to yank the wingtips off in a matter of minutes, I can see a couple of drawbacks. firstly, as piano hinges wear, I've seen them make gray dust similar to smoking rivets and from a pure vanity point, the piano hinges don't have any screws out there to attach a go-pro camera for really cool videos.

I'm installing an archer antenna in the right wingtip as well as LED lights in the tip and landing lights just inboard in the leading edge, So I'd like the ability to access that stuff without drilling out a bunch of pop rivets, so I ultimately decided to go old school here and just stick with nutplates.

I elected to go with #6 screws. Normally I despise #6 screws because they are easy to shear, but the way this stacks up is: dimpled wing skin, countersunk wingtip & then a nutplate. I don't think the flange in the fiberglass wingtip is thick enough to accommodate the bigger (deeper) countersink that would be required for a #8 screw.

I had upsized and dimpled the holes in the wing outboard flange some time ago so now I upsized the holes I had previously match drilled in the wingtips, and utilizing a nutplate jig, laced into the wingtips drilling and attaching nutplates, as well as countersinking for the skin dimples to nest into.

FYI- at the skin seam at the spar, there is one location top and bottom where the screw holes are too close together for two standard 2-leg nutplates to reside next to each other. One of the nutplates needs to be a 1-leg, otherwise the legs are right next to each other. I only mention it here because it would be easy to get drill happy with a nutplate jig if you didn't realize it.

On the right wingtip I'm installing an archer antenna so I took some time to review the installation instructions for it as well as VAF to determine the best location fore/aft. I clamped it in position when I was final sizing those nutplate holes because it gets sandwiched between the fiberglass tip and nutplates which electrically bond it back to the airframe.

I got the left wingtip nutplates all installed and all the holes drilled in the right wingtip before I ran out of time tonight. Turns out there are 38 nutplates per wingtip. If you consider that each nutplate requires 3 holes and in this case all three require countersinks in the fiberglass, thats 114 holes and 114 countersinks per wingtip. holy cow, no wonder this took forever.