It is a folding 6 rotor helicopter, inspired in X6 helicopter.
i would like to build in polyethylene technical plastic, it is light, shock resistant and easy to work with my cnc mill.
propellers are in a circle of 500mm diameter, i think best option in order to use standard RC parts is to use 6 x 12" counter rotating propellers.
3 (counter rotating) propeller of 12" have an 8% more surface than 4 propellers of 10" (like typical quadrotors)
Probably 14" propellers are better in order to get more performance but i think is not possible to find very low Kv motors with the necessary low power and low weight.
Any idea are welcome!