Brief Description: Prepare the Centre Section Bulkheads
The first steps (no photos) are to attach a couple of Retainer Blocks, whatever they are. I final-drilled the holes but left the riveting to later. It seemed odd that one pair of holes were countersunk and the other pair were dimpled, and these were effectively drilled out.
I need to prime the parts beforehand, and I am still considering at what point to paint interior parts that will be visible. These will be some sort of battleship grey, and ideally should be painted before assembly. This may cause a delay until I have paint to hand, as the top half of the bulkheads (at least) will be on show.
Next up is to cleco on the aft bulkhead so that holes can be match-drilled into the very substantial c-channel that is part of the forward bulkhead assembly. Picture 1 shows the two bulkheads clecoed to the bottom skin. The funny angle is because the bottom skin will eventually be angled upwards towards the tail.
Picture 2 shows the clamps holding the aft bulkhead to the c-channel. I found that the aft bulkhead skin was just a fraction of an inch (maybe 20 thou) higher than the c-channel.
Picture 3 shows the amount of swarf that was being created as I started to match-drill 75 #30 holes into the c-channel. The plans call for 72 holes, I found 75 to do, and that excludes two large holes at either end of the unit. I was making heavy weather of this drilling until I remembered that I had some Boelube drilling oil. This made the job much easier on the drill and on me. On reflection, it might have been easier to mount the bottom skin vertically with the bulkhead flat on the end of the workbench (ie.d rotated through 90 degrees).
