Aerodynamic Interference on Trim Characteristics of Quad-Tiltrotor Aircraft

The aerodynamic interference between the different components of quad-tiltrotor (QTR) aircraft were considered to analyze its influence on trim characteristics. A comprehensive method with the fixed-wake model was developed for multiple aerodynamic interactions, improving the accuracy of the flight dynamics analysis. Additionally, a more general control strategy was developed to tackle the redundant control issue of the QTR, improving its control efficiency by coordinating the authority relationship of various control surfaces across the flight range. Then, the trim features were calculated in the helicopter mode, conversion mode, and airplane mode, and the relevant results with and without interaction were compared. The results show that the aerodynamic interaction mainly influences the body’s vertical force, longitudinal force, and pitching moment. Furthermore, there are significant differences between collective and longitudinal sticks and pitch attitudes. The interference plays a major role in helicopter and conversion modes with a less-than-30-degree tilt angle.