Of the aspects of all this that kept me awake at night, undoubtably the motor-mounts and undercarriage have most often had me weeping gently into my pillow. At 04:00 today however I figure out a solution for the mounts, and as I've already solved the skids the design of the basic airframe is something of a done deal.
With this in view I dismantle the mock-up intending to re-use the parts, together with odds and sods knocking around the workshop, in a half-scale working model. Or not quite, as they're all close enough to the required size without being exact, but I'm not going to destroy the planet for an inch here and there.
I start then with a rebuild of the centre-section, although upped from the 12" square used in the mock-up to the 15" here that I had kicking around. The cantilevers you see here are those lengths that formed the sides of the mock-up's airframe, and these I have left at 24" as I couldn't be bothered getting the jig-saw out. Me at Airbus: "Office please Hilton and explain why one wing is longer than the other?"
I've also repurposed the 18-gauge aluminium tubing for this, though 1/16th would have been my tipple of choice.
Here's a tip though: to line this up in the absence of what professionals call a jig, take two of your cantilever arms and bolt then parallel as shown, using the remaining pair (as indicated by the mystery gloves) as a simple prop. Then BEFORE you rivet the two remaining arms in place, drill the 6mm holes required in order to bolt the abutments together in a material embrace.
All of this works, and only too well. Am unable to re-use the three-way plastic tube connectors used in the mock-up, because they're now stuck faster than Excalibur. Always use silicone instead of mastic, children, if you're going to dismantle the drone. Meanwhile below, in today's double-picture feature, we can see how the assembly is flipped over in order to mark up parts for drilling:
