Hey, an Ardupilot newbie here. I am working on a new project ( agricultral spray drone)
the drone will have 240kg total take off weight with 16pcs motor.we would use U15II motor , set up will be U15II KV80 + Flame200A ESC + G40*13.1" propeller at 60V voltage .
Here is the motor detail specification http://store-en.tmotor.com/goods.php?id=731
What motor/frame arrangement do you plan to use? As Mike says a DodecaHex (coax Hex) is the highest motor count craft supported by ArduCopter as far as I know. Max outputs on a typical Pixhawk/Cube Flight Controller is 14.