RE: B-36
those are wing spars they were originally bolted to the fuse bulkheads with machine screws and nuts.the whole fuselage and wing center section were one piece with the wing tips removable just outbord of the last nacelle.once the spars are affixed to the formers you then add the ribs.this technigue is a pain.i came up with a removable wingby adding a plywood wingsaddle through the bulkheads in the wing area and the adding bals blocks from the saddles to the saides and sanding them to contour of the bulheads then sheeting the fuse,this leaves the wing saddle area solid so you can get a good hand hold with out crushing the skin..email me as i think i have a scan of all the kit parts i can send you to look at.