there are 6 center ribs that go between the front and rear spar. 3 on each side of the centerline. the side of the rib with the flanges are always on the outside (away from the centerline).
each side of the rib is different. the side with the tooling hole closest to the edge is for the front spar. I drew a rivetline on each flange that was 10mm from the end of the flange.
tried to center the rib on the front spar as best as i could.. there is only a small area where the flange lays completely flat against the spar (due to the curve of the spar's doubler). lined up the rivet line, clamped, drilled/cleco'd
I did this for all 6 ribs.
REAR SPAR:
I positioned the spar so that the ribs were sticking up in the air. i laid the rear spar on top of these ribs. i eyeballed things and loosely clamped the 6 rib flages to the rear spar -- this was to help stop things from wobbling around too much.
I began at the center ribs.. lined up the rivet line through the CNC'd holes. drilled, cleco'd.
all 8 holes in each rib was drilled with a #30. i didnt bother with #40 pilot holes because i was out of the smaller-sized cleco's.
