A Cascaded trim method of electric aircraft subject to propulsive constraints in wing-borne flight

Emerging electric aircraft face challenges from novel propulsion systems and limited energy density, demanding accurate and efficient performance prediction during wing-borne flight. This paper proposes an augmented cascaded trim method addressing these needs. Key system dynamics are formulated as nonlinear equality constraints with steady state condition. A cascaded approach is developed to sequentially solve critical airframe and propulsion states using derived analytical solutions. These solutions explicitly account for the battery discharging dynamics and electric propulsive constraints. This cascaded analytical approach eliminates the need for computationally expensive full numerical simulation or collocation methods, significantly enhancing computational speed. The method is applied to generate a payload-range diagram. Compared to conventional power-based trim benchmarks, it reduces range prediction error by over 59%. In a second application determining the level-flight envelope, the critical bound of propeller rotational speed is derived analytically using Cauchy’s mean value theorem. Analysis reveals that battery energy consumption imposes a more stringent limit on motor duty cycle than maximum load current. The proposed method fundamentally differs from prior conventional power-based trim or optimization-based methods by leveraging cascaded analytical solutions without time derivatives. This ensures high-accuracy trim analysis for electric aircraft at low computational cost once primary aerodynamic and propulsive data are available.