Upper shelf complete

Well, in terms of structure, this thing is done. Tonight was just attach points laid out and wrapped up.

The shelf attaches to the two forward braces, both of which have a Z-shape profile. At the forward end, the horizontal part of the shelf lays on top of the middle of the brace, while at the aft end, the vertical part of the shelf sits just behind the brace flange. The forward spot was pretty easy; I laid out the holes, drilled them, and installed the nutplates. The attach hardware here will be AN3 bolts; way stronger than needed, but these mount holes will double as attach points for the adel clamps that will hold the wiring harness trunk.

The aft end was a bit more interesting. Since the shelf and the brace mate in a vertical plane, that means there’s no natural support for the weight of the shelf unless the screws or installed. My intent is for this shelf and all it components to be removed as a unit for service, which would probably make this a cumbersome choice. So I decided to add some support tabs on the shelf, to allow it to rest naturally in place even with no screws installed. Some scrap Z-bracket material from the fuel tanks worked great for this; I just made two small angle tabs and attached one at each end:

Then it was just the same routine of laying out the screw holes, drilling, and getting the nutplates installed. Here I’m just using #8 screws, which is probably about all I could manage anyway, as there’s a lot less material on the flange as opposed to the center of the brace.

So here it is, the shelf installed in the fuselage:

And a different angle, showing the forward attach hardware. I added the adel clamps just to give an idea of what the wiring routing would look like:

I’m kind of wondering if I should use screws here instead of the bolts. My thought with the bolts was that using a screwdriver deep behind the panel and up against the baggage bulkhead would be unpleasant. But getting these bolts started through the adel clamps isn’t exactly fun either. For now I guess I’ll stick with this, and see how much I hate my life when the time comes to install this shelf for real…

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