Decoupling pitch and angle of attack with a variable-incidence wing extends quadrotor flight endurance

The aerodynamic efficiency of conventional lifting-wing quadrotors is severely constrained by the rigid coupling between fuselage pitch attitude and wing angle of attack (AoA), which prevents the vehicle from maintaining optimal lift-to-drag performance across varying flight speeds. This study presents a novel variable-incidence lifting-wing quadrotor that effectively decouples fuselage attitude from wing aerodynamics. The proposed mechanism incorporates a 143 g lightweight lifting wing and a dual-actuator drive system, with a total structural mass penalty of only 209 g. High-fidelity Computational Fluid Dynamics (CFD) simulations, reveal that the variable-incidence strategy alleviates detrimental rotor-wing interference. Specifically, a fuselage pitch of - 20° combined with a wing AoA of 10°-12° reestablishes a strong suction peak on the wing's upper surface, maximizing passive lift. Systematic flight experiments validate the decoupling control strategy, demonstrating that the prototype achieves a maximum normalized power-saving ratio of 42.98% at 10 m/s relative to hover. Furthermore, even when accounting for the 209 g structural weight penalty, the design provides a net 13.22% efficiency improvement over the fixed-incidence concept of the original RflyLW. Leveraging these aerodynamic enhancements, predictive analyses indicate that the UAV can achieve an extended maximum flight endurance of 46.8 min and a practical range of 28.1 km. These results, showing high consistency between numerical predictions and experimental data, offer a robust and highly efficient solution for extending the endurance of UAVs in energy-constrained environments.