Day 21: Flaperon Spars ( 2hr 5m)

At the end of the previous day I had been concerned that the “natural fit” of the ribs to the spars did not mesh with the statement in the photo manual of how the flanges should face. So, I started the day with an examination of this and could not work out why some ribs appeared perfectly situated but “wrong”. I took measurements from the plans and put them on the metal so I was absolutely sure what everything was and where it went. And then I worked out that the “natural fit” went both ways. A quick swap of the ribs on the inboard spars had everything in the right place and, although I had made a silly mistake, I was proud of myself for spotting it and working out what I had done wrong without running to the builder forums.

Regular readers will know what’s coming up next (and maybe I should develop an acronym since I’ll be writing this over and over)… I drilled out all the holes to size 30 using the copper clecos. Once all spars were drilled they were disassembled so that all the holes could be deburred and primer applied. I continue to only put corrosion protection where metal joins with metal.

Once the primer was dry I reassembled the spars and riveted all the holes with A4 rivets.

The next step in assembling the spar is to add a hinge bracket next to each nose rib. The bracket gets riveted to both the nose rib and spar. First the bracket needs to be drilled to the right position and trimmed to size. To accomplish the former each of the 8 brackets was marked with the location of the holes and then drilled to size 40 for clamping to the spar.