Analysis of Propeller Performance with a Modular Blade Element Momentum Method

Accurate, low‑cost prediction tools are essential for the rapid sizing and optimisation of propellers used in emerging electric‑propulsion architectures. The current work extends the classical Blade Element Momentum Theory (BEMT) through a modular suite of aerodynamic corrections that account for (i) three‑dimensional rotational augmentation, (ii) compressibility effects at moderate tip‑Mach numbers and (iii) post‑stall behaviour via a smoothed Viterna polar extrapolation. The framework is investigated on two different test cases, a four‑blade Beaver propeller and a two‑blade APC 10×7 propeller, over advance ratio ranges representative of hover, climb and cruise of an eVTOL. Validations against experiment data have shown that the full correction set reduces mean absolute errors in thrust and torque coefficients from around 18% down to 6% across J from 0.6 to 1.0 for the APC~10×7 propeller. A detailed sensitivity study demonstrates that inappropriate aerofoil polars (e.g.\ NACA~0012) can distort integral performance by more than 25% and alter spanwise loading trends qualitatively; the proposed Viterna blending routine reduces the potential issue caused by out-of-range polar by enforcing physically consistent lift and drag characteristics for the AoA up to $\pm90^{\circ}$. The work therefore delivers (i) an extensible, open‑source BEMT implementation, (ii) a robust polar extension technique and (iii) a comprehensive validation dataset that may serve as a benchmark for future mid‑fidelity propeller models. These contributions support the reliable application of BEMT to distributed propulsion and eVTOL design studies where hundreds of operating points must be evaluated in real time.