Integrated preliminary design of fuel cell propulsion systems for vertical take-off aircraft

Abstract This paper presents a preliminary design study of a fuel cell-powered vertical take-off and landing (VTOL) aircraft. We compare the fuel cell-powered aircraft to a battery-powered aircraft and discuss the influence of key propulsion system design parameters on the aircraft mass and energy consumption. To this end, we have developed a physics-based fuel cell propulsion system design tool and coupled it with an aircraft design environment. We used the resulting integrated tool to design two four-seat VTOL aircraft with tilting propellers, one of which is powered only by batteries and the other uses PEM fuel cells supported by high-power batteries for take-off. The results show that a target aircraft mission range of 160 km is easily achievable with fuel cells, while the range with batteries alone is limited to 112 km. The fuel cell aircraft is 25 % lighter for the same payload. However, its energy consumption is 2.7 times higher, accounting for hydrogen production by electrolysis. Results of fuel cell aircraft design studies indicate that substantial oversizing of the fuel cell stack is useful to achieve low mission fuel consumption. Furthermore, the study shows that the support of the fuel cell with batteries for vertical flight phases is required to achieve a low aircraft mass and fuel consumption. In summary, we show that fuel cell propulsion systems have both advantages and disadvantages compared to battery propulsion systems for VTOL aircraft. Further, we present an integrated design method for the design of fuel cell-powered VTOL aircraft that can be used for different aircraft and mission requirements.