Acoustic noise suppressing ducted fan propulsor mounting arrangement and treatments

An acoustic noise suppressing mounting arrangement for a ducted fan assembly comprising:

• an outer duct through which air is entrained on one end and ejected on the other;
• a central shaft assembly comprising:
• at least one rotating member, wherein the at least one rotating member comprises at least one of a fan, a propeller, an impeller, and a rotor;
• and
• a shaft power source configured to provide shaft power to the at least one rotating member, wherein the shaft power source comprises an external drive shaft, an electric engine, an internal combustion engine, or a turbine engine;
• and
• one or more bearing assemblies 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;
• and
• a plurality of structural spokes coupled to the central shaft and 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 is pretensioned and has a high aspect ratio, and wherein the plurality of structural spokes comprise aft-swept structural spokes and forward-swept structural spokes.