Development of towed-type multi-rotor with fixed stabilizers

Recently, multi-rotors are rapidly spreading. One of the problems with the conventional multi-rotors is short flight duration due to battery limitations. Therefore, the tethered multirotors which can obtain unlimited flight time by wire feeding have been proposed in recent years. On the other hand, the range of operation of the tethered multi-rotors is limited by mooring with the tether. This paper focuses on the towed-type multi-rotor system, which is connected to a vessel or a vehicle like a tractor with tether. In this paper, the towing simulation was performed in order to clarify the behavior of the multi-rotors under towing. From the result of the simulation, it was found that the position of tension application on the airframe must be in a narrow band area near the center of gravity of the airframe. In addition, the horizontal tail is effective in improving the stability during towing. The experimental aircraft was developed based on the factors obtained by the simulation which were related to the stability during towing. Finally, the towing experiment was successfully held, and sufficient pitch stability and altitude stability were confirmed.