Propulsion flow path duct systems and methods

A method of forming a flow path duct system for a propulsion system of an aircraft, the method comprising:

• forming the flow path duct system between an inlet nozzle and an outlet nozzle, wherein the inlet nozzle defines a single fluid flow path, and wherein each of the single fluid flow path of the inlet nozzle and the outlet nozzle has a high aspect ratio;
• forming a plurality of perforations through a base defining a flow surface between an internal surface and an external surface;
• extending a plurality of supports defining a plurality of cavities from the external surface of the base;
• fluidly coupling one or more of the plurality of cavities with one or more of the plurality of perforations, wherein said fluidly coupling comprises fluidly coupling the one or more of the plurality of cavities with an internal volume defined by the internal surface of the base through the one or more of the plurality of perforations;
• and
• securing a backing surface to the plurality of supports, wherein said securing comprises disposing the plurality of supports between the base and the backing surface.

An aircraft comprising:

• a propulsion system including a flow path duct system extending between an inlet nozzle and an outlet nozzle, wherein the inlet nozzle defines a single fluid flow path, wherein each of the single fluid flow path of the inlet nozzle and the outlet nozzle has a high aspect ratio, the flow path duct system comprising:
• a base defining a flow surface, wherein the base has an internal surface and an external surface, wherein a plurality of perforations are formed through the base between the internal surface and the external surface;
• a plurality of supports defining a plurality of cavities, wherein the plurality of supports extend outwardly from the external surface of the base, and wherein each of the plurality of cavities is in fluid communication with at least one of the plurality of perforations;
• and
• a backing surface secured to the plurality of supports,
• wherein the plurality of supports are disposed between the base and the backing surface, and
• wherein the plurality of cavities are in fluid communication with an internal volume defined by the internal surface of the base through the plurality of perforations.