A strong interest in highly-efficient, small-scale propeller configurations can be recognized, especially due to the currently growing number of and usage possibilities for unmanned aerial vehicles (UAVs). Although a variety of different propulsion concepts already exist on the market or are discussed in the literature, there is still a demand for a systematic investigation to compare such configurations, in particular, small-scale propellers with a fixed pitch, which are analyzed in this work. Therefore, different configurations of small-scale propellers with a fixed pitch are analyzed in this paper. They were operated as isolated single propellers and as ducted propellers in a cylindrical wing. Furthermore, due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reverse inflow. These non-axial inflow conditions have a major influence on the flow field around a propeller. In order to investigate this influence, all analyses were performed at a range of inflow angles in relation to the propeller axis from ${\alpha }_{disc}=0°$ to $180°$.

Currently, a growing interest for the propulsion of unmanned aerial vehicles (UAVs) can be recognized. To adress this, small-scale fixed-pitched propellers are analyzed in this work, both in isolated and ducted configurations. Due to their flight envelope, UAVs are likely to operate at highly inclined inflow conditions and even under reversed inflow, having a major influence on the flow field around a propeller. In order to investigate this influence, all analyses are performed at a range of inflow angles from α_disc = 0° to 180° relative to the propeller axis. This paper employs different numerical techniques and compares them regarding their capability of showing the influence of non-axial inflow on propeller configurations. Wind tunnel experiments are performed measuring the forces and visualizing the flow field with PIV as well as steady and unsteady RANS simulations are applied to study details of the flow field.