As an architect I’d like to mention how a little geometry might help performance some.

If the four arms attaching the motors were to attach at the corners, rather than a the center of each side, the same length arms would be further away from the center, and less of the propwash would touch the edge of the board. The arms coming out flat at a 45 degree angle, not square with the board..

From a theoritical point of view, a small three motor unit might be even better, with a tirangular board and arms coming off each corner. Unfortunatly the math might be a lot more complcated, and it might look wierder as well. Just my two cents.

Good work.

For the radio we have this design because the board was already crowded enough (then the copter was routed the 3axis gyros didn’t exits yet) and we though that for a first shoot we would skip doing the 2.4Ghz PCB design. We plan to integrate the radio chip and antenna on board for the next version.

As for a tessellation-friendly PCB shape, I don’t think there is any way to make a 90+% usage tessellation that doesn’t end up with a bunch of unused PCB space in the copter, which is nothing more than dead weight. Unfortunately, I think there’s nothing to be done about that except hope it can be run in a panel that can put useful boards in that dead space.

The radio bothers me though, as that’s something that could be replaced with a nrf24 mounted directly on the PCB.