Abstract: An additive manufacturing (AM) system includes a housing defining a chamber, a build platform disposed in the chamber at a first elevation, and a lower gas inlet disposed at a second elevation and configured to supply a lower gas flow. The AM system includes a contoured surface extending between the lower gas inlet and the build platform to direct the lower gas flow from the second elevation at the lower gas inlet to the first elevation at the build platform, where the contoured surface discharges the lower gas flow in a direction substantially parallel to the build platform. The AM system also includes one or more gas delivery devices coupled to the lower gas inlet to regulate one or more flow characteristics of the lower gas flow, and a gas outlet configured to discharge the lower gas flow.

Abstract: A system includes an airfoil disposed inside an engine assembly that includes a pressure side and a suction side that are coupled together at a leading edge and a trailing edge. The airfoil extends a radial length away from a central axis of the engine assembly between a hub end and a tip end. The airfoil includes a sweep feature disposed at the leading edge that is shaped to alter the air inside the engine assembly. Altering the air inside the engine assembly reduces a surface unsteady pressure level on the airfoil. The system includes a fan frame assembly comprising an inner and outer surface. The hub end is coupled with the inner surface and the tip end is coupled with the outer surface. The airfoil is integrated with the fan frame assembly such that the airfoil increases a structural load supporting capability of the fan frame assembly.

Abstract: An acoustic core includes an array of resonant cells. The array may include a plurality of coupled resonant cells respectively defining an antecedent resonant space and a subsequent resonant space, with at least one cell wall having one or more wall-apertures defining a pathway between the antecedent resonant space and the subsequent resonant space. The array may include a plurality of high-frequency resonant cells respectively defining a high-frequency resonant space and being matched with respective ones of the plurality of coupled resonant cells. A cross-sectional dimension of the one or more wall-apertures defining the pathway between the antecedent resonant space and the subsequent resonant space may be less than a cross-sectional dimension of the antecedent resonant space and/or a cross-sectional dimension of the subsequent resonant space.

Abstract: An additive manufacturing (AM) system includes a housing defining a chamber, a build platform disposed in the chamber at a first elevation, and a lower gas inlet disposed at a second elevation and configured to supply a lower gas flow. The AM system includes a contoured surface extending between the lower gas inlet and the build platform to direct the lower gas flow from the second elevation at the lower gas inlet to the first elevation at the build platform, where the contoured surface discharges the lower gas flow in a direction substantially parallel to the build platform. The AM system also includes one or more gas delivery devices coupled to the lower gas inlet to regulate one or more flow characteristics of the lower gas flow, and a gas outlet configured to discharge the lower gas flow.

Abstract: In some embodiments, an airfoil comprises a proximal end; a distal end opposite said proximal end; a distal portion extending adjacent said distal end; an edge extending between said proximal end and said distal end; and a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion, wherein the distal portion extends over an acoustically active portion of the airfoil.

Abstract: An aircraft defines a longitudinal direction, a vertical direction, and a transverse direction. The aircraft includes a fuselage; and a wing extending from the fuselage generally along the transverse direction and defining an outer end along the transverse direction. The wing includes a wing tip assembly at the outer end of the wing, the wing tip assembly defining an axis substantially parallel to the longitudinal direction of the aircraft and a circumferential direction extending about the axis, the wing tip assembly including at least three stationary guide vanes spaced along the circumferential direction from one another.

Abstract: A propulsion system for an aircraft includes an electric propulsion engine configured to be mounted at an aft end of the aircraft. The electric propulsion engine includes an electric motor and a fan rotatable about a central axis, the fan driven by the electric motor. The electric propulsion system additionally includes a cooling system operable with an airflow over the aft end the aircraft when the electric propulsion system is mounted to the aircraft. The cooling system is configured to cool the electric motor during operation of the electric propulsion engine.

Abstract: An aircraft assembly includes an engine, and intake, and a propeller assembly. The engine is mounted to at least one of a wing or fuselage of an aircraft. The intake is configured to provide air to the engine. The intake includes a body having an engine inlet through which air enters the intake. The propeller assembly includes propeller blades coupled to and driven by the engine. The propeller assembly is spaced an axial distance from the inlet opening of the intake wherein air passing by the propeller blades enters the intake. The propeller assembly has a propeller configuration that is at least one of sized or shaped to optimize performance of the propeller assembly based on an interaction between the propeller assembly and the intake.

Abstract: An aircraft defines a longitudinal direction, a vertical direction, and a transverse direction. The aircraft includes a fuselage; and a wing extending from the fuselage generally along the transverse direction and defining an outer end along the transverse direction. The wing includes a wing tip assembly at the outer end of the wing, the wing tip assembly defining an axis substantially parallel to the longitudinal direction of the aircraft and a circumferential direction extending about the axis, the wing tip assembly including at least three stationary guide vanes spaced along the circumferential direction from one another.

Abstract: An aircraft assembly includes an engine, and intake, and a propeller assembly. The engine is mounted to at least one of a wing or fuselage of an aircraft. The intake is configured to provide air to the engine. The intake includes a body having an engine inlet through which air enters the intake. The propeller assembly includes propeller blades coupled to and driven by the engine. The propeller assembly is spaced an axial distance from the inlet opening of the intake wherein air passing by the propeller blades enters the intake. The propeller assembly has a propeller configuration that is at least one of sized or shaped to optimize performance of the propeller assembly based on an interaction between the propeller assembly and the intake.

Abstract: An aircraft defines a longitudinal direction and includes a fuselage extending between a forward end and an aft end along the longitudinal direction of the aircraft. An aft engine is mounted to the aft end of the fuselage. The aft engine further includes a nacelle including a forward section. An airflow duct extends at least partially through the nacelle of the aft engine and defines an outlet on the forward section of the nacelle for providing an airflow to the forward section of the nacelle.

Abstract: An apparatus configured to reduce acoustic interactions between a propeller and a surface of an aircraft positioned downstream of the propeller includes a surface modification element of the surface of the aircraft. The surface modification element defines a modified contour of the surface. The modified contour is configured to decorrelate a phase distribution of a plurality of sound sources within a source field positioned on at least a portion of the surface.

Abstract: An engine for mounting in or to an aircraft includes a stage of compression airfoils rotatable about a central axis; a casing surrounding the stage of compression airfoils and defining an inlet; and a low-distortion inlet assembly mounted within the inlet. The inlet assembly includes one or more structural members mounted at predetermined locations around a circumference of the central axis within the inlet, the predetermined locations defining an airflow distortion exceeding a predetermined threshold; and at least one airflow modifying element configured within the inlet so as to reduce airflow distortion entering the stage of compression airfoils.

Abstract: An additive manufacturing (AM) system includes a housing defining a chamber, a build platform disposed in the chamber at a first elevation, and a lower gas inlet disposed at a second elevation and configured to supply a lower gas flow. The AM system includes a contoured surface extending between the lower gas inlet and the build platform to direct the lower gas flow from the second elevation at the lower gas inlet to the first elevation at the build platform, where the contoured surface discharges the lower gas flow in a direction substantially parallel to the build platform. The AM system also includes one or more gas delivery devices coupled to the lower gas inlet to regulate one or more flow characteristics of the lower gas flow, and a gas outlet configured to discharge the lower gas flow.

Abstract: An aircraft defines a longitudinal direction, a vertical direction, and a transverse direction. The aircraft includes a fuselage; and a wing extending from the fuselage generally along the transverse direction and defining an outer end along the transverse direction. The wing includes a wing tip assembly at the outer end of the wing, the wing tip assembly defining an axis substantially parallel to the longitudinal direction of the aircraft and a circumferential direction extending about the axis, the wing tip assembly including at least three stationary guide vanes spaced along the circumferential direction from one another.

Abstract: In some embodiments, an airfoil comprises a proximal end; a distal end opposite said proximal end; a distal portion extending adjacent said distal end; an edge extending between said proximal end and said distal end; and a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion, wherein the distal portion extends over an acoustically active portion of the airfoil.

Abstract: An aircraft includes a fuselage extending between a forward end and an aft end. An aft engine is mounted to the aft end of the fuselage, the aft engine defining a centerline. The aft engine further includes a nacelle having a bottom section, the bottom section having a forward lip. The forward lip of the bottom section defines a camber line. The camber line, in turn, defines an angle relative to the centerline of the aft engine greater than or equal to at least about five degrees.

Abstract: An aircraft is provided including a fuselage that extends along a longitudinal direction between a forward end and an aft end. A boundary layer ingestion fan is mounted to the fuselage at the aft end and is configured for ingesting boundary layer airflow off the surface of the fuselage. The fuselage defines a profile proximate the boundary layer ingestion fan that is optimized for ingesting a maximum amount of boundary layer air and improving propulsive efficiency of the aircraft. More specifically, the fuselage defines a cross sectional profile upstream of the boundary layer ingestion fan that has more cross sectional area in a top half relative to a bottom half as defined relative to a centerline of the boundary layer ingestion fan.

Abstract: In some embodiments, an airfoil comprises a proximal end; a distal end opposite said proximal end; a distal portion extending adjacent said distal end; an edge extending between said proximal end and said distal end; and a surface extending between said proximal end and said distal end, said edge and said surface defining a sweep and a cahedral through said distal portion, wherein the distal portion extends over an acoustically active portion of the airfoil.

Abstract: A system includes an airfoil disposed inside an engine assembly that includes a pressure side and a suction side that are coupled together at a leading edge and a trailing edge. The airfoil extends a radial length away from a central axis of the engine assembly between a hub end and a tip end. The airfoil includes a sweep feature disposed at the leading edge that is shaped to alter the air inside the engine assembly. Altering the air inside the engine assembly reduces a surface unsteady pressure level on the airfoil. The system includes a fan frame assembly comprising an inner and outer surface. The hub end is coupled with the inner surface and the tip end is coupled with the outer surface. The airfoil is integrated with the fan frame assembly such that the airfoil increases a structural load supporting capability of the fan frame assembly.