Wing yaw-control technology based on distributed jet rudders

To address the heavy mechanical structure weight, poor low-speed control effectiveness, and severe moment cross-axis coupling caused by yaw control of stealth-constrained flying wings using Split Drag Rudders (SDR), this paper proposes an innovative yaw-control method based on distributed Jet Rudders (JR). Unlike existing active flow-control approaches that primarily regulate the momentum coefficient, the proposed distributed JR maintains a constant momentum coefficient while rapidly switching jet-deflection combinations to form different yaw-control schemes and achieve discretely tunable yaw-moment outputs. A wing distributed JR wing model was built based on wind tunnel tests, and six yaw-control schemes were designed based on yaw-control requirements. The control effectiveness and cross-axis coupling characteristics of SDR and the distributed JR were compared under different control schemes, and Particle Image Velocimetry (PIV) was used to quantify trailing-edge flow field structures before and after actuation. Results show that, over angles of attack from -6° to 6°, the optimal distributed JR scheme yields a drag exceeding that of 80°-deflected SDR and generates larger yaw moment than that of 60°-deflected SDR. Over angles of attack from -6° to 14°, the mean rolling-moment increment is 4.38%, which alleviates the moment cross-axis coupling compared with SDR. Flow field analysis shows that JRs form protrusions similar to virtual bumps on the wing surface and block the incoming flow, which serves as one of the main mechanisms for drag and yaw moment generation. The JR can potentially assist or replace SDR, and provide technical support for yaw control of advanced aircraft without rudders.