I need to complete the correct and final trim to the forward flanges of the 623 corner ribs, and to do that I need the floor at the correct angle. Fortunately for me I have some botched parts from a previous F-706 bulkhead attempt that I can use. I dug those out of my scrap bin and used them to cleco the F-770 side skins on. This gave me the best chance at getting the correct angles to work with.
I could then easy mark and trim the flanges of the corner ribs to meet the F-705 bulkhead flanges.
I was then set up to easily mark out the aft ends of the F-623 corner ribs with perfect reference to the F-706 bulkhead.
I was then ready to match drill the bottom skin to the F-623 corner ribs. This isn't as straight forward as you would think. The ribs don't quite match the edge of the skin as the drawings indicate. This took a bit of messing around on my part. Clamping, checking, repositioning, repeat....till I was happy.
A closeup of my rough fit. I still need to round the corners.
I need to trim the inboard flange of the corner rib on the aft end to prevent contact with the baggage rib.
I was then ready to match drill the corner ribs.
Next step I needed to make the Forward F-623A attach straps. I deviated from the plans and opted for a larger strap that ensures good edge distance. I started first with cutting some cardboard scrap as a template.
I could trace the holes and confirm the proper edge distances. I then used 0.032" scrap and cut the larger wedges out of that.
Check fitting...Looks good.
After match drilling and some TLC on the 3M wheel, here's how it looks.
Now to work on the Aft F-623A attach straps. Think this will be just as tedious.
