Blade Element Momentum Modeling of Low-Re Small UAS Electric Propulsion Systems

A model for the propulsion system of a small-scale electric Unmanned Aircraft System (UAS) is presented. This model is based on a Blade Element Momentum (BEM) model of the propeller, with corrections for tip losses, Mach effects, three-dimensional flow components, and Reynolds scaling. Particular focus is placed on the estimation of scale effects not commonly encountered in the full-scale application of the BEM modeling method. Performance predictions are presented for geometries representative of several commercially available propellers. These predictions are then compared to experimental wind tunnel measurements of the propellers’ performance. The experimental data supports the predictions of the proposed BEM model and points to the importance of scale effects on prediction of the overall system performance.

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