US Patent 10889366 Ducted thrusters

An aircraft comprising a pair of ducted thrusters. Each of the ducted thrusters comprises a duct surrounding a rotor assembly with a rotor hub having a plurality of rotor blades extending therefrom, wherein the plurality of rotor blades have a modulated angular distribution about a central longitudinal axis of the duct. Each of the ducted thrusters further comprises a stator assembly having a stator hub with a plurality of stator vanes extending from the stator hub to an interior surface of the duct, wherein each of the plurality of the stator vanes are angularly modulated around the stator hub such that angular spacing between pairs of adjacent vanes of the plurality of stator vanes varies for each pair of the adjacent vanes.