Preliminary Sizing of an eVTOL Lift-Cruise Aircraft

Abstract This paper describes a methodology for the preliminary design of a lift-cruise aircraft with an electric propulsion system. This methodology has used the actual data of electric vertical take-off and landing to estimate the take-off weight. The central element in this methodology is a matching diagram, which obtains performance equations for fixed-wing and rotary-wing modes. Based on the matching diagram, two design areas are obtained. The first design area is for the fixed-wing mode, which can be selected as the optimal design point for achieving power loading and wing loading. The second design area is for the rotary-wing mode, which can be selected as the optimal design point for achieving power loading and disk loading. The initial design is done based on the design points and the obtained take-off weight. The end-step take-off weight is estimated based on the weight components, and the design process is repeated, which is a small error between the initial and final take-off weight. Finally, the aircraft’s optimal size and power are obtained. In the final section, this methodology has been used for the preliminary design of a lift-cruise aircraft with four passengers.