I just completed closing the bottom skin panels of my RV8 wings last weekend. The job was not as difficult as I had feared after reading various comments about how challenging or impossible it was. I was reticent of tackling this job all by a single person. The first sign of encouragement this is doable after I stumbled on this Youtube channel from a Swiss builder.
I am 5'6" so my arms are not that long. But this goes to show an average person can do this too. There was no rivet on the RV8 bottom wing that was not reachable if I could find the optimum body position and to rivet it without physical distress.
I first started to work on the right wing. This took one full weekend and a few week nights to complete. The left wing was considerable faster, about 10 hours total spanning slightly more than one weekend day.
In this post I am going to show a few methods I found helpful for me. You may find these helpful too. You may have other solutions for your build but, hopefully, this post will add to the wealth of information found on VAF and other excellent build sites.
1. Bucking bar: I decided to buy this tungsten bucking bar after some test dry-run and realized the standard iron tools were not very easy to handle by one person bucking and riveting at the same time. (https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1
This small, and heavy, bucking bar could fit into tight area, and it allowed my finger tip to hold it in the far reaches of the wing. As seen in the second picture
, by chance, it has the perfect length that one end can be rested on the tip of a cleco while I buck the other rivet hole at the other end. Finger pressure was all it needed. This model has a bevel tip, which was helpful in some places. Since the tungsten bar is so narrow, I built up the width by applying a few strips of masking tape so it could held securely, even with sweaty fingers.
2. Flush Rivet Tool: I used the surplus Boeing flush rivet head that I bought from Browntools. I found that I could reliably pound a AN426 head rivets without too much pressure while using one hand. There was zero smiley on the bottom skin. I wish I learned how to use this tool earlier on. Unfortunately, Browntools ran out of their surplus supplies so you can to buy it new from them, at a higher price. The polymer on this rivet head is softer than the hard rubber found on the regular consumer rivet head. Browntool says this is the best of the best, which I found it to be true.
Note: the standard retainer spring will not fit to this rivet head. I fashioned wire retainer with a length of stainless steel safety wire
3. Dry-Run: It was important for me to dry-run the riveting sequence in the difficult areas before I did the actual riveting. I simulated the riveting by cleco-ing the holes and tested if my bucking arm can fit into the wing. I found the method effective because I did not have to reverse the riveting because I had gone too far. It was also helpful for me to mark the sequences on the skin vinyl, which rivets to stop, and the directions to insert my arm.
4. Flat or Vertical: I rivet both with the wings in the Flat and Vertical positions. For the closely spaced root ribs, I placed the wing flat on the workbench because it was easier to rivet the rear-spar and the bottom rib holes without having to bend the skin as much. After the root ribs were all done, the wing went back on the dolly, in the vertical position. The job went smoothly from then on.
5. The Lapping Double Row: On the first wing (right wing), I tried to rivet the double lapping row last. On the left wing, I riveted this region first. I found riveting this region first was easier. One caution about riveting the double row first was I had to make a lot more frequent fit-check of the outer skin panel to ensure it was straight to the tip. There was no time that it was misaligned but I still think it was a good practice. There was a very slight oil canning on the right wing at the bay next to the double row. I don't know it was because the double row was riveted last. There was no oil-canning on the left wing.
6: SB 16-03-28 Interference: This SB applies to all later kits of all the models. The SB added two aluminum channels behind the rear spar. I found two rear spar flange holes interfered with the reinforcing channels of this SB so there was no way to buck using the standard AN426 rivets. Instead of grinding out a portion of the SB part to fit the bucking bar, I used a couple of Cherry rivets instead.
That was it. Good luck on your build. If you are building in the Southern California and need help to kick start the closing of your RV wing, send me a PM.