The Study on the Aerodynamic Characteristics of the Transition Phase during the Take-Off of Compound Tilt-Wing Aircraft

Compound tilt-wing aircraft have made innovations based on traditional tilt-rotor aircraft, offering advantages such as high efficiency, high speed, high stability, and high reliability. However, due to the uniqueness of their variable configurations, the aerodynamic characteristics during the tilt transition phase are extremely complex. This paper investigates the transition schemes and aerodynamic characteristics during the take-off transition phase by controlling boundary conditions such as flow velocity, lift rotor speed, pusher rotor pitch angle, and nonlinear speed transitions. The research results indicate that by controlling the uniform speed transition of boundary conditions, the total vertical force can overcome the aircraft’s gravity to complete the transition from helicopter mode to fixed-wing mode. However, the total vertical force exhibits strong nonlinearity with changes in the tilt angle, which leads to the aircraft flying in a nonlinear climb posture during the take-off transition, resulting in poor safety and stability. After optimizing the nonlinear speed control of the boundary conditions, the total vertical force can change more stably with the tilt angle, allowing the aircraft to achieve a more stable altitude-hold transition flight, significantly improving the stability and safety of the flight.