Control Design and Flight Test of Aerodynamics-Driven Monoplane–Biplane Morphing Aircraft

Increasing the aspect ratio of the wing of an aircraft reduces drag and increases its range and endurance. However, a large wingspan complicates takeoff and landing. Therefore, an aerodynamics-driven monoplane–biplane morphing (MBM) aircraft was proposed, which cruises as a high-aspect-ratio monoplane and takes off and lands as a biplane, switching between two patterns during flight. This concept of MBM was validated in our previous work via wind tunnel experiments. We further develop it beyond this phase and introduce its applications under real flight conditions here. We constructed a test plane with a wingspan of 6 m and conducted a series of flight experiments on it. To examine its performance and facilitate its initial flight test, we built aerodynamic and dynamic models of the aircraft to analyze its morphing behavior through simulations. The corresponding controller algorithm and hardware system were also developed. The successful implementation of these systems enables bidirectional morphing during flight from a large-span monoplane to a half-span biplane. The test results, comprising data and photographs, validated the success of these trials. The concept of MBM, the corresponding models, and the control algorithm for morphing were thus verified.