8/13/23 - 0.7h 8/14/23 - 0.2h I'm counting this step as complete even though I still need to go back and properly torque all of the nuts on the left and right aileron torque tubes. I decided to leave things finger-tight until the aileron rigging is complete. I will probably have to assemble and disassemble the aileron control system a few times while I finish up various wing systems like the autopilot servo bracket and the aileron trim system. This step in the plans is straight-forward, but it does take a little patience. Essentially, the aileron torque tubes are installed through the large hole in the wing spar, and the ends of the torque tubes go into the flanged bearings that were attached to the inboard ribs at the start of the wing build. In order to install the torque tubes, the forward and aft torque tube assemblies need to collapse toward each other on the torque tube collar. The forward torque tube assembly and torque tube collar go in first, and then the aft torque tube assembly goes on the collar after it is routed through the wing spar. I pushed the aft torque tube assembly on the collar beyond the bolt holes to get clearance to align the torque tube with the flanged bearings attached to the inboard wing ribs. The torque tubes need about an inch of clearance, which means the collar has to go about an inch further into the forward and/or aft torque tube assemblies. Once I had the forward and aft torque tube assemblies on the torque tube collar and aligned with the flanged bearings, I could extend the total assembly to align the bolt holes and re-insert the torque tube assembly bolts. Both the left and right torque tubes had just a little play fore and aft, which was remedied with a washer on each end between the torque tube and the flanged bearing. I had to remove the torque tube bolts one more time to collapse the assembly to allow me to slip in the washers. In my case, one NAS1149F0463 washer on the aft end and one NAS1149F0432 washer on the forward end resulted in a really good fit of the torque tube extended to full length and bolted (finger tight) together. The movement of the torque tube is silky smooth with negligible friction, no binding, and no out-of-plane rotation. The only issue I noticed was the aft torque tube assembly may rub against the wire harness connected at the root rib, so I'm going to try to pull those wires away from the torque tube arm with some wire lacing anchored to the ground wire next to the bottom wing skin. The final task in this step is to find the “neutral position” of the forward torque tube subassemblies. The plans specify a distance of 2 17/32” from the center of the torque tube clevis arm (note the language here - it'll come up again in the next step! :-) ) to the fuel tank. I set up a small square to that distance, that I can clamp to the clevis arm to easily measure the distance. The next step will set the neutral position of the bellcrank, which is when the torque tube clevis arm neutral position measurement will also come into play. For now, I'm happy to have a quick and repeatable way to measure the distance.