Visually not a lot has changed since my last update. In preparation for printing most changes have been minor dimensional tweaks. Generally speaking the clamping interfaces are opened up slightly to ensure they go together easily and actually clamp to the tube. Fastener holes are closed up slightly to allow drilling of a clean hole after printing.
One of the last unanswered questions I had with this design was where the battery connector would join to the power distribution board and how it would generally fit into the layout. My initial plan was to run it out through a grove in the outer surface of one of the end clamps. The reality of this is that there is very little space between tube and the plates on each side, certainly not enough for 16AWG silicone wire (as fitted to the battery) without squashing it. The plan instead is to run the connecting wires out through one of the slots which can now be seen in the top plate above. The battery is raised with the self adhesive rubber ‘feet’ stuck on top. Also now visible in the image above are the cutouts to accommodate a battery strap or two.
I’ve also done a lot of the work getting the top board laid out. My approach with this is more ‘suck it and see’ than design perse. I’ve not checked current carrying capacity of via’s or the +ve and -ve planes. The board is laid out with:
- Direct connections for battery power to the escs
- A place for the 5v step-down
- 5v accessory connection points front, rear and centre
- JST connector for 5v connection to the flight controller
- JST connector for battery voltage to the flight controller.
I’ve been debating how integrated to make the bottom board (hosting flight controller and receiver). I think it will probably be a better choice to keep it simple and mount these components with fasteners or double sided tape rather than trying to solder them in permanently. I am however a bit of a sucker for the clean look of soldering them in directly as impractical as this is for servicing. Stay tuned for an update on this front, I will need to make a decision in short order as I will now be waiting on fabrication of these for assembly.