To evaluate the performance and blade load distribution of a propeller, windprop, wind turbine, or propfan we first review the capabilities and limitations of Glauert's Blade Element Method (BEM) and then hybridize BEM with numerical integration of helical wake effects to enhance accuracy and accommodate sweep. Next, we introduce a vector definition of local blade sweep, review and renew simple 2D sweep theory for lift and drag, and then demonstrate the first successful application of a lifting-line method to evaluate swept-blade propfan blade loads at transonic Mach number. Here, we introduce "cascade" and "semi-empirical Prandtl-Glauert" effects on downwash-line shape, with flow and aero properties taken normal to the lifting line such that the normal Mach number remains subsonic, hub to tip. In all cases, the methods are validated with test data. Finally, we introduce an open-source EXCEL application to illustrate aerodynamic design of a human-powered-aircraft propeller, regen-electric-aircraft "windprop," and notional high-speed-electric propfan.
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