Step 9: bridge the gap in the angled bulkhead with some 1/8 lite ply and sand to shape.

Step 10: IMPORTANT STEP! build a new spine using the plywood pieces from the old spine. I was able to re-use the old pieces for the three aft bays, but I had to build new pieces for the bay just behind the angled bulkhead. I cut the balsa cap off the old spine and sanded the top of the T-section flat.

Building a new spine is important for at least one practical reason: when working on your model inverted in a cradle, you don't want to crush the fuselage sheeting aft of the canopy.

Step 11: (not shown) use 3/16 inch square balsa to form a lip on the inside edge of the fuselage sheeting, effectively forming a new stringer on each side of the fuselage. This step will ease the installation of the new sheeting by forming something like a lap joint and not relying on merely an edge joint to join the old sheeting to the new sheeting.

Step 12: Sheet the area with 3/32 balsa. Don't worry too much about gaps between the sheeting--they can be filled with filler just prior to re-covering.

Viola! You're over halfway done! Next up, the hatch.