Multicopter is one of the UAV, which is now used in various field including aerial photography, agricultural field, various information gathering, delivery services, and so on. Another ambitious application is emergency delivery in the event of disaster. To apply the multicopter for the emergency delivery, larger load capacity, longer cruising distance, and higher-flying speed are required. One of the inevitable elements for these requirements to improve is reduction of energy consumption for flying and hovering.

One possible solution is enlargement of rotor size and lower rotor revolution speed. This paper reports the results of experimental investigation on effect of size and revolutionary speed of rotor for the relation between energy consumption and lift force. In addition, four rotor multicopter with variable pitch rotor was experimentally manufactured. This experimental multicopter is also reported in the paper.