Attach wingtip ribs 11 and associated structures

Previously I reworked a fold error in the outer connection angles to resolve some serious issues with getting the rib 11 hinge bracket to fit together. I adjusted the outer surface to line up with the outermost edge of the rear spar channel, such that the aileron hinge would but up against this channel. Further examination revealed I have overdone things a bit, and in anticipation of this I purchased replacement outer connection angles.

These replacement angle also have enough fold tolerance to create hole alignment issues, so I reworked these as well but to a lesser extent. I was able to get everything to fit together if the fold was adjusted such that a 1mm gap exists between the aileron hinge bracket surface and the outermost edge of the rear spar channel. As these outer connection angle were received, just as with the originals, there would have been a 2mm gap here which throws everything else out.

I hammered down on the flange with the 4.8mm holes, so as to shorten the angle in the lateral direction, as mounted. This moved the flange with the 4mm holes aft with respect to the rear spar channel. As there was a gap of nearly 1mm present there to close, this was the sign that this was to critical dimension to correct.

The Aileron hinge bracket was secured with 4.8x15mm rivets. I included the custom made grommet holder for the nav/strobe light cable.

A fold position error was also present in the spar rib attachment angle, about 0.7mm, which was responsible for a corresponding degree of mismatch in the fore-aft direction between the 4mm rib 11 holes and the angle holes. This became evident when rib 11 was fully clecoed into place with alignment between the skin holes and rib 11 flange holes. As this angle had already been riveted to the spar, and the alternative of upsizing to 4.8mm rivets provided a good alternative to removal and hammer adjustment of this angle, I took that option. 4.8x10mm rivets were used here.

The ribs 11, by design fell into place with near perfect alignment with the skin rivet holes. Occasionally a 0.1-0.2mm misaligment needed to be cleaned out. Interestingly, the right hand leading edge skin had to be handled a little to follow the rib 11 outline, this was not need for the left hand leading edge. All holes were able to be lined up with appropriate cleco sequencing.

I noted - for the right hand rib 11- that if I allowed the fore-aft misalignment to relax to include a vertical mismatch of the 4mm angle holes of comparable magnitude, then the leading edge skin did not need this slight forcing. However I did not take this latter route, instead choosing to force the mismatch to be purely fore-aft, by pushing rib 11 upwards a little to better align it vertically relative to the main spar.

In order to deal with the oversized flange holes at the tips of the (Rev 0) ribs 11 I used the strap "washer" constructed earlier. In retrospect I am pretty sure the 3.2mm rivet tail would have swelled quite nicely into the 4mm holes and secured the offending tabs well, or even better than the scheme I have adopted here.