Drilling the crotch strap brackets and clecoed the center section3h
October 12, 2022
More work on the center section parts.
The first thing was to install the crotch strap brackets. The original plan was to clamp them tight to the center section, then use an angle drill to drill the holes. However, as it turned out, my angle drill is too big to fit!
Instead, I marked the position of the bracket on one of two seat ribs and drilled the holes using a long drill bit, through the opposite hole in the bracket (yes, the photos show two different brackets, but the process was the same!).
Then I clamped the bracket to the center section assembly and drilled the second side of the bracket the same way.
After that, I used a file to modify the flanges of the seat ribs to allow installation of a snap bushing for the electrical wiring.
Then clecoed everything together. I can drill the parts, but probably not rivet them. Since I don't have the center bulkhead, I won't be able to drill and dimple the front part of the skin and the seat ribs.
The Van's FAQ "A common RV-7/7A and RV-9/9A fuselage construction question" allows to countersink instead of dimpling, which would have solved the problem. I prefer dimples, however.