Today was one of those trying days where it feels like I would have been better off if I hadn't put any effort in the project at all. I worked on the aileron mounting and the wing rib inboard of the aileron. This was a time for some headscratching. Despite all the drawings of the plane, some areas are vague or incomplete. This is one of those areas. The challenge is that the aileron hinges extend beyond each end of the aileron. The hinge at the outboard end of the aileron is a pin that threads into the end of the aileron and is secured with a cotterpin and an oversized, custom made locknut. The pin extends about 2 inches beyond the aileron and it fits into a bearing that's mounted within the tip ribs of the wing. The inboard end of the aileron hinge connects to the aileron torque tube connector. This end is permanently fixed. So the challenge is to fit something that's about 2150 mm long into a gap that's only 2054 mm long. (Since this is a French design, all the dimensions on the plane are listed in millimetres.) Since there's an access plate on the inboard end to allow one to connect the aileron to the aileron torque tube, it seemed like that should be the area that I'd have to modify to allow assembly. For mounting the aileron, my plan was to insert the pin in the outboard end into its bearing, swing the aileron over the middle bearing, and have the inboard end feed through a slot in the corresponding rib and then mount the inboard hinge bracket. I had trimmed the rib in this area and after much fiddling and cutting, it became obvious that the best solution would be to mount the aileron in the opposite order. That is, inboard end first, then swing into place, with the tip end lined up last. This would require having the outboard hinge pin out during assembly and then once the aileron was in place, thread the pin in place and attach the bracket and bearing for the pin. Of course, this means that there's the need for an access panel at the tip. Looking at the drawings again, it now appears that that's how it was done. It wasn't so obvious before. While doing this, I checked the alignment of everything and discovered that the hinge points on the aileron aren't perfectly in line. The aileron is an aluminum structure and there's no chance for any adjustment so things must have been out of alignment when it was built. With only the inboard and middle hinges in place, the outboard hinge pin wanders by about 1/16 of an inch when the aileron is deflected through its full range of travel. This results in a bit of friction in the assembly when everything is fully snugged up. Not ideal but still less friction than some control surfaces I've seen. The positive of today is that I have a better understanding of the assembly and have a plan for tomorrow. I'll have to make a new section of rib to replace the one I'd cut today but that's easy enough.