  Multicopters are becoming increasingly important in both civil and military
fields. Currently, most multicopter propulsion systems are designed by
experience and trial-and-error experiments, which are costly and ineffective.
This paper proposes a simple and practical method to help designers find the
optimal propulsion system according to the given design requirements. First,
the modeling methods for four basic components of the propulsion system
including propellers, motors, electric speed controls, and batteries are
studied respectively. Secondly, the whole optimization design problem is
simplified and decoupled into several sub-problems. By solving these
sub-problems, the optimal parameters of each component can be obtained
respectively. Finally, based on the obtained optimal component parameters, the
optimal product of each component can be quickly located and determined from
the corresponding database. Experiments and statistical analyses demonstrate
the effectiveness of the proposed method.
