First off I completed riveting the interior ribs. Then I riveted the inboard rib. The inboard rib flange also “faces in”, so it needs to be riveted before riveting the front spar of the flap. The access is a little tricky around the plate nut and aft most solid rivet. The two aft most rivets on the top and bottom get pulled rivets (MK319BS).
Then, I clecoed in the flap front spar and used LP3-4 pulled rivets to attach the forward flange of each in interior rib and the most outboard rib to the spar. The upper wing skin proximity makes access with the tool difficult for the top rivet. A couple scrap 4x4 wood blocks fit well to hold the skin back while you pull the upper rivets. The most inboard rib is also attached to the spar with LP3-4’s. These go through FL706A, the spar, and the rib. These rivets have their own access issue because the rivets are close to the FL706A flange and the rivet puller tool interferes with the flange. Some builders have modified the rivet puller by grinding the tool to fit. I took another approach by offsetting the tool slightly with a “bushing” over the stem between the rivet and tool. My “bushing” was a bicycle spoke nut out of the junk drawer. It was the right diameter and height. It worked well.
Inboard rib
Pulling the LP3-4's. Wood blocks help with the access
