Mini foldable quadcopter

This is the second version, after my design with the removable arms, which you can find here:
https://www.thingiverse.com/thing:2839097

This is designed for the same electronics as that one.

Shopping List

OK, here's the main electronic components needed for this build:

BeeRotor F4 flight controller: http://rctimer.com/product-1771.html
HGLRC 13A ESCs (x4): https://www.banggood.com/BS13A-2-3S-13A-BLHeli_S-16_5-BB2-ESC-Support-Dshot150-Dshot300-Dshot600-p-1162419.html
AX1304 2000kV