Acoustic noise suppressing ducted fan propulsor mounting arrangement and treatments

A method for mounting components of a ducted fan assembly, the method comprising:

• coupling at least one rotating member to a shaft power source to form a central shaft assembly, wherein the at least one rotating member comprises at least one of:
• a fan, a propeller, an impeller, and a rotor, and wherein the shaft power source comprises an external drive shaft, an electric engine, an internal combustion engine, or a turbine engine;
• coupling the central shaft assembly to an outer duct via one or more bearing assemblies, wherein the outer duct is configured to allow air to enter on a first end of the outer duct and eject the air from a second end of the outer duct, and wherein the one or more bearing assemblies are configured to rotatably secure the at least one rotating member within the outer duct and to transfer thrust loads between the outer duct and the central shaft assembly;
• coupling a plurality of structural spokes to the outer duct and the central shaft assembly, wherein the plurality of structural spokes are configured to transfer loads between the outer duct and at least a portion of the central shaft assembly, wherein each structural spoke of the plurality of structural spokes has a high aspect ratio, and wherein the plurality of structural spokes comprise aft-swept structural spokes and forward-swept structural spokes;
• and
• pretensioning each structural spoke of the plurality of structural spokes.