Trimmed and sanded all extraneous plywood and all epoxy joints. Sanded the foam ribs down to the proper contour - they were slightly oversized from the factory, which is good.
Prepared the partial rib that carries the control horn. I modified the structure here - moved the location of the control horn down by 25mm, similar to how SD-2 rudder is designed. So I had to make a special partial rib, not per the plans. I erroneously thought that attaching this subassembly (partial rib with the control horn) would be easier after assembling the main skeleton of the rudder with the one side skin. But the geometry of the horn is such that it cannot be inserted into a small opening in the skin. I had to make a larger opening in the first skin. But it all worked out OK in the end.
Drilled, riveted with epoxy the main control horn to the partial rib. Glued the control horn + rib subassembly into the main structure.
