Longitudinal Static Stability and Trim Conditions Analysis of eVTOL in Steady Level Flight Based on CFD and Ducted-fan Test

This paper presents a preliminary study of the force-moment balance and static stability of a tandem-wing tilting ducted-fan Vertical Take-Off and Landing (eVTOL). Based on both ducted-fan static thrust level experiments and simulations, we evaluated the steady level flight of the aircraft in the longitudinal plane. We conducted static thrust tests on the ducted-fans to establish the power-thrust relationship, Subsequently performed external flow simulations of the complete eVTOL using CFD, and momentum sources were used to approximate the ducted-fans. Simulations were carried out at different angles of attack, freestream velocities, and ducted thrust levels. Based on these results, we balanced the aircraft's forces and moments, which is a prerequisite for operating condition in steady level flight. Ultimately, we demonstrated that this set of flight operating condition in steady level flight is viable and reasonable under multiple physical constraints, and we provided an admissible range for center of mass (CoM) placement, offering recommendations for structural design and loading configuration.