1/21/24 - 1.0h
1/22/24 – 0.7h
Fitting the wing tips will likely be a stop-and-go step for me – essentially a filler for gaps in my build schedule that won't get finished until much later in the build process. I plan to take the EAA Sportair Workshop “Fiberglass Techniques for RV Aircraft” in the near future to learn about how to work with and finish fiberglass parts on the RV-14A including the wing tips. Until then, there are some things I can do now on the wing tips.
Like every step in the build process, I started with a review of service bulletins, notifications and letters, and revisions and changes in the Service Information and Revisions section on Van's Website. My plans are up to date, and there weren't any changes or safety notices for the wing tips.
The wing tip plans are relatively short at only 4 pages total, but they cover a lot of ground. The plans also leverage Section 5.18 of the plans, which contains several important notes when working with pre-molded fiberglass parts like the wing tips. One note in particular discusses the alignment of the trailing edge of the wing tip with the trailing edge of the elevator, and how the alignment can lead to inconsistent gaps between the aluminum wing and fiberglass wing tip. The note also cautions against allowing the metal edge of the wing to ride up onto a fiberglass edge radius. There should be a 1/8” to 1/16” gap between the metal edge of the wing and the fiberglass edge radius. That gap will get filled in later with some epoxy resin and cotton flox, and then sanded smooth for a seamless transition from aluminum to fiberglass. Section 5 also recommends having some dedicated tools for fiberglass work since the fiberglass is very abrasive and will quickly dull drill bits and cutting blades. Finally, there is a note in Section 5 to “use soft rivets or do not fuly set normal rivets (shop head height approximately 1.2x the hole diameter). Section 5 has lots of important tidbits!
The plans involve a lot of fitting, trimming, and drilling to install the navigation light lens, nutplates for mating with the wing, and aft wing tip rib. The primary difference with this section of the plans is working with plexiglass and fiber glass instead of aluminum. The plans did not specify the type of screw to attach the navigation light lenses, so I'll probably go with the same screw used to attach the wing tip to the wing – AN507-6R6. The instructions to install the wing tip rib into the wing tip were also a bit confusing – the instructions start by attaching the wing tip to the wing, and then inserting the wing tip rib into the aft edge of the wing tip. I'm not sure how that will work with the wing tip attached to the wing, but perhaps it will be clearer when I get to that point.
The plans for this section call out a special tool, a 10 foot ratchet strap, to help snug the wing tip into the wing prior to drilling the mating holes. I have also set aside some drill bits and a counter-sink bit for this section and future fiberglass work. In addition, I acquired a set of drill bits for plexiglass from a former builder, and I decided to buy a nut plate jig and rivet layout fan. Each wing tip takes 44 nutplates, and I think the nut plate jig will really help with the task of locating, aligning, and drilling the holes for the nut plates. The rivet layout fan should come in handy when I layout the rivet pattern for the wing tip rib, and I'm sure it will get more use later in the build.