Determining the Efficiency of Small-Scale Propellers via Slipstream Monitoring

A large part of small-sized UAVs that are used for surface scanning, video- and photography, or other similar applications the multirotor type. These small aircraft perform mainly in hovering nearly flight mode, endurance these vehicles depends greatly on efficiency their motors aerodynamic thrust-generating systems, including propellers, ducted fans, etc. Propellers may therefore work different regimes: a regime where propeller performs to move vehicle through air, static regime, which standing air is accelerated. In both cases, concept can be describe propeller’s performance. There have been several previous studies advancing propellers’ performances. studies, when determining propeller, thrust power coefficients most commonly compared evaluate Sometimes, inducted velocities calculated via momentum theory. As small-scale propellers very low Reynolds (Re) numbers below 500,000, flow type transition boundary layer separation make it hard predict actual mode. Therefore, aim this paper introduce method determine directly empirically comparison between output input power, wherein determined measured mean induced velocity. The combines thrust, torque, angular velocity measurements with slipstream monitoring. performed tests showed decrease efficiency, Re number rising spite values coefficient. This study led two main conclusions: not always key parameters propeller; role yet clear requires further investigation. presence effects has proven numerous works, but impact those seems as trivial claim lower number, weaker