Comparison studies on aerodynamic performances of a rotating propeller for small-size UAVs

A better prediction of key aerodynamic parameters of a propeller is necessary to improve the performances of unmanned aerial vehicles (UAVs) in different operating environments. In this work, we conduct a systematic investigation on an APC 1045 multi-rotor propeller to analyze its aerodynamic performances with wind tunnel tests, blade element momentum theory (BEMT) and 3D computational fluid dynamics (CFD). The theoretical BEMT model provides accurate and reliable estimation at the advance ratios ≤0.567, whereas the method begins to stall at advance ratios ≥0.661. Conversely, the results obtained from CFD simulations agree well with the experiments at all advance ratios, with the differences in thrust- and power coefficients around 5% and 4%, respectively. The present work compares the aerodynamic parameters while varying the freestream velocity to investigate the limitations and advantages of the use of the aforementioned three different methods. Given the limitation of the BEMT, it is found to be reliable enough to estimate the aerodynamic parameters of a small-scaled fixed-pitch propeller. In addition, a more comprehensive investigation of the BEMT shows that increasing advance ratio decreases the lifting portion of the propeller blade, i.e. incurring more losses associated with the hub and tip.