Tailcone avionics mounting

I added a lightening hole to the avionics shelf (keeping its edge about 3/4" from the nearest screw holes):

Tailcone avionics shelf with a lightening hole removed with the fly cutter

and then riveted the left shelf nutplates in place (for the contactors):

Left-side shelf with nutplates riveted on

I drilled holes for an AN366F nutplate on the bellcrank mount to use as the main grounding point, only to realize that the edge of the nutplate would collide with the bellcrank rib:

Battery mount bracket with nutplate hole for grounding point, one rivet hole going beyond the edge of the underlying part

Many facepalms later (if only I had shifted the position just a bit...), the solution I picked was to switch to a MS21081-4 corner nutplate, which can still use two of those holes (that nutplate also seems relatively hard to find, so I ordered mine from a shop in Alaska!):

Battery mount bracket with a 90-degree nutplate to stay clear of the underlying part

With that in place, I removed primer from the surface that will have contact with the washer, for better conductivity:

Battery mount grounding point with primer removed

I then re-assembled the whole thing, re-connected the pushrod, attached the servo mounts, etc.:

Tailcone area with battery mount, left shelf, and servo brackets back in place

The only real steps left for this section are to final-install the contactors and batteries.

Time lapse:

Total tailcone rivets: 1904

Total tailcone time: 243.4h