Evaluation of quad ducted-fan helicopter

Purpose - With the purpose of clearing up the risk to rotor blades, this paper develops a quad ducted-fan helicopter using four ducted-fans instead of four rotor blades in a quad rotor helicopter. Design/methodology/approach - Auto hovering test, auto cruise test, and altitude control simulations were conducted to estimate the flight performance of the quad ducted-fan helicopter. Findings - Flight performance of the test quad ducted-fan helicopter is almost same as a commercial quad rotor helicopter, and it succeeds to decrease the risk to the rotor blade. However, endurance is shorter than that of the quad rotor helicopter, because of the ducted-fan characteristics. Research limitations/implications - The test quad ducted-fan helicopter can fly for about four minutes with two packs of fourcell (16.8 V)-2200 mAh Lipo batteries, and it needs about 3.3 times as much energy as quad rotor helicopter. The authors will improve the performance of quad ducted-fan helicopter by aerodynamics analysis and design of ducted-fan system Practical implications - This is expected to reduce the risk of rotor blade mounted on multi rotor helicopter. Social implications - The research will facilitate the development of safety autonomous multi-copters in various civilian applications. Originality/value - The research purpose is to realize safety multi-copter flight using ducted-fan instead of rotor blade.