While waiting for an answer from SPA about mounting the horizontal stabilizer, I decided to make a required modification to the vertical stabilizer front spar stiffener before mounting it to the fuselage. The modification consisted of trimming 1/8” off each side of the mounting pad. About three minutes with a jig saw had it reduced to the proper size, and another 20 minutes with a couple of files and a 3” diameter scotch pad in a die grinder, had it properly cleaned up.
Today I received a one-foot length of 5/8” square X 0.035 wall 4130 steel tube, to develop my process for dimpling the forward fuselage tube. The first trial used a 100-degree male dimpling die mounted in a modified pair of geared pliers. The result is shown in Image #3. I’m not happy with the outcome yet because the dimpled skin does not fully seat against the square tube, causing pillowing around the rivet after it is squeezed. More process development to follow.
