Control features and application characteristics of split drag rudder utilized by flying wing

The high-aspect-ratio flying wing eliminates vertical tail and conventional rudder, and uses instead a split drag rudder with large deflection as its directional control surface. Based on wind tunnel test data, the control features of a split drag rudder is discussed, including its nonlinear yaw control, low directional control efficiency with small deflection, strong additional force effects and 3-axis coupling controls; and then the impact of the split drag rudder on the aerodynamic performance and stability features of the aircraft is analyzed. Application characteristics of the split drag rudder in every flight phase are summarized. For example, due to its low directional control efficiency with small deflection, the split drag rudder may maintain small deflection in some flight phases where the aircraft doesn't need high stealth performance so as to quickly generate enough control effectiveness. From the overview of flight control design and control allocation application, in order to provide enough control effectiveness and give full play to the feature of additional drag, it is concluded that it is suitable for the split drag rudder to adopt the both-side-independent-deflect mode and the strategy of optimized drag control allocation.