Effects of propulsion type on the cruise aerodynamic performance and stability of electric vertical take-off and landing aircraft: a comparative study

Abstract

With the rapid development of the low-altitude economy, electric Vertical Take-off and Landing (eVTOL) aircraft have emerged as a key focus of advanced air mobility. Open rotor and ducted fan configurations are the two primary types, but their distinct effects on aerodynamic performance and stability require thorough quantitative investigation. This study establishes a high-fidelity computational framework based on the Reynolds-Averaged Navier–Stokes (RANS) equations, incorporating eddy viscosity corrections and the Multiple Reference Frame (MRF) method to accurately resolve the interactional flow fields between the open rotor/ducted fan and the airframe. The results demonstrate that the open rotor configuration significantly enhances the cruise lift-to-drag ratio, thereby improving cruise efficiency. In contrast, the ducted fan configuration exhibits superior pitch and yaw static stability, especially under crosswind conditions. The ducted fan generates a nose-down pitching moment and contributes to improved directional stability. However, both configurations are found to compromise roll stability. Quantitatively, this study clarifies the complementary advantages of open rotor and ducted fan systems in terms of efficiency enhancement and stability performance, providing valuable insights for propulsion system selection and conceptual design of eVTOL aircraft.