Propeller blade performance in low-pressure environments

There have been increasing applications of propeller-driven flyers in non-Earth environments where significantly lower ambient pressures are present. This work experimentally studies the performance of rotor propeller blades of an airfoil profile in low-pressure environments by varying the aspect ratio ( ), angle of attack (α), and rotational speed of the blade. The experiments are performed in a vacuum chamber to investigate performance at various ambient pressures ranging from 3 to 96 kPa, resulting in a Reynolds number range of 300–27 500. Thrust and torque on a two-blade rotor are measured. The thrust (CT) and power (CP) coefficients of the propeller increased with α and [ ] while they were not influenced by ambient pressure levels, except for the lowest pressure tested here (3 kPa). The thrust to power ratio (CT/CP), however, decreases with the ambient pressure and α, suggesting a reduction in performance. At lower ambient pressures (