The combined engine powered wide-speed range morphing aircraft demonstrates horizontal takeoff capability from conventional civil airfields, exhibiting adaptability to diverse terrain and application scenarios, and can achieve flight speeds exceeding 5Ma. The integration of morphing aerodynamic configurations into this aircraft architecture significantly enhances its operational speed range and spatial coverage, thereby optimizing flight performance across extended speed regimes and expansive flight envelopes. An aircraft model with variable-sweep wing configuration was established including the shape structure, aerodynamic model and power model, and the coupling characteristics in the model were analyzed. The trajectory in the take-off and climbing phase was segmentally optimised on the basis of the Gaussian pseudo-spectral method. Comparative analysis between morphing-wing configurations and fixed-geometry counterparts revealed critical performance advantages. Simulation results demonstrate that the proposed wide-speed range morphing aircraft model exhibits dual-coupling characteristics involving propulsion-flight interaction and morphodynamic coupling. It also proves that the sweep angle changing can effectively improve the climbing efficiency and fuel saving performance in the take-off and climbing phase.