Fabricated the side stringers tonight. After tracing out the stringer pattern from the original factory ones, I cut it out with my new shiny jigsaw cutter (bought a Bosch) and a new fine toothed blade for a smoother cut. It was a lot better than the first attempt with the cheaper ply, but no matter how hard I tried, I couldn’t seem to get a perfectly straight outside curve, and spent a heap of time sanding and filing down the outside edge to get it smooth enough. It still isn’t perfect, but I’m hopeful it’s good enough to get away with it, and that it wont show through the fabric.
I then used a new router bit with a tighter radius to put a bottom and top curve onto the outside edge, and used a file to debur the inner edges. Then I set about fitting them. I made the stringers all slightly longer, and had to manualyl fit an adjust the indentations at the end of the stringers to match the tubing layout I have. This is because my S-1S plans show the old C tube layout. Strange. Anyway, after much trial fitting, I got them as close as I could, and rilled holes and attached them to the fuselage as a trial fitting.
This happened for all four stringers. The bottom ones I did slightly differently. Instead of just tracing out the stringer, I put a curve in them and clamped them to the bench and cut them out with a curve already built in. I had flexed the top ones, and they didn’t move, so I figured having less tension in the stringer would be a better bet – considering this is ply, and not straight wood.
This took a long time, made a lot of sawdust, and when I almost knocked the fuselage off it’s stands, realised I was tired and needed to call it a night. I’ll tackle the lower bulkheads and stringer tomorrow.
Time expended: 4.5hours. Total time: 612 hours.