Rear fuselage replacement rib 7 and manufacture flange doubler

The original rear fuselage rib 7 structure had issues. The original RF-RIB-701-C-A-2 had fold position errors exceeding 2mm on the upper and middle side flanges, making the part too narrow and sending the 4mm holes far out of alignment. I reformed the upper flanges to bring the bottom and middle holes of the upper side flanges into alignment, but was concerned about weakening of the metal. I supplemented these flanges with two doublers that spanned a part of the web, upper flange, and top side flange. The middle side flanges were supplemented with shims. The result was again quite solid, but after discussion with Sling a replacement for this part was thought a better option, as well as for RF-BKT-007-C-A-0 which had a fold position error of a nature throwing off the alignment of the AN3 bolt holes.

Great customer support from Sling once again!

The following photos show the rebuild, with the replacement parts

Everything fit perfectly with the replacement parts, except that the top side flanges were a little tight within the rib 902 flanges. A small amount of material was sanded at the top end of these flanges making them very slightly thinner. I did not want to attempt to reform such thick material, fearing cracking. In any case the top hole of the top flanges misaligns with the corresponding rear side skin and the top rib 902 holes, by about 0.8-1mm. This was dealt with by recentering and upsizing to 4.8mm. Even prior to such upsizing, the distance between the hole centre and flange edge is small. The recentering was such (downwards) such that this was not further reduced by upsizing to 4.8mm. In any case I dealt with this by creating a doubler which spanned all three holes of the upper side flanges