October 28th, 2012

Spent most of the week either working, doing chores, or in Atlanta at Becca's last big band competition. They did well, but missed finals by 1/10th of a point, which was a bit disappointing. They did very well though, and had a lot of fun. It was great to get to go so see them compete against so many excellent bands from all over the south.

 This week I finished up the 904 bulkhead assembly. Started off installing nutplates all along the top of the main fore and aft bulkheads. I assume these will later be used to screw down the seat pans (haven't read that far ahead in the plans yet).

 I then finished up the attach angles, installed nutplates in the ribs and angles, then riveted the ribs and attach angles to the forward spar (no pictures at all - totally forgot to take any).

 After that, they have you fabricate a couple of close tolerance spacers that are used to make sure that the two bulkheads are exactly the right distance apart when they are finally riveted and bolted together.

 Here is one of the two spacers - they have to be exactly 1 7/16 inches long. I cut them a bit long on the band saw then chucked them into my drill press and snuck up on the correct dimension by running the tubing up against a fine metal file on the drill press table. This also ensures that they are exactly square on each end.

From Fuselage

The last thing to do is to make a couple of precision wood spacers (also 1 7/16" thick) to test how the wing spars will fit. These are drilled oversize where the spar attach bolts go, then the entire thing is bolted together to validate that everything is assembled and fits correctly.

From Fuselage

You can also see the bushings for the fuel lines have been installed in the forward ribs. They are the black nylon parts.