Systems and method for active control of stationary vortices for aerodynamic structures are disclosed herein. In one embodiment, a method for active control of vortices over a solid surface includes: generating vortices proximate to the solid surface; sensing locations of vortices by printed skin sensors; and maintaining the vortices in their fixed spanwise positions with respect to the solid surface by actuation of printed skin actuators.

The present disclosure is directed to an aerodynamic stabilizer assembly for stabilizing an aft fan mounted to a fuselage of an aircraft. For example, the stabilizer assembly includes one or more generally horizontal stabilizers for mounting to a nacelle of the aft fan and the fuselage so as to stabilize the aft fan. Each of the generally horizontal stabilizers includes an inner portion and an outer portion. As such, the inner portions are mounted to a nacelle of the aft fan and the fuselage at a predetermined downward angle with respect to a central axis of the aft fan so as to direct airflow upwards and into the aft fan, the outer portion being mounted to the inner portion.

The present disclosure provides a system, method, and apparatus for a protective finish for an airfoil. In one or more embodiments, the disclosed method involves providing a sheath, and applying the sheath to the surface of the airfoil. In one or more embodiments, the sheath wraps around the surface of the airfoil from the leading edge of the airfoil towards the trailing edge of the airfoil. In at least one embodiment, the sheath covers approximately 50 percent to approximately 70 percent of the chord length of the airfoil. In some embodiments, the sheath is manufactured from at least one polymer, such as a polyurethane and/or a floropolymer. In one or more embodiments, the airfoil is a winglet, a raked wing tip, and/or a wing.

A method of improving optical characteristics of an optical window operating in a flow of fluid and having first and second panes of optically transmissive material—each having an edge adjacent to, parallel with, and at least partially coextensive with each other—is described herein. The method includes inserting a thermally conductive blade between two adjacent edges of the first and second panes of optically transmissive material; and lifting an adverse flow stagnation zone forward of the optical window by protruding the thermally conductive blade into the flow of fluid from an outer surface of the panes of the optical window.

A method of improving optical characteristics of an optical window operating in a flow of fluid and having first and second panes of optically transmissive material—each having an edge adjacent to, parallel with, and at least partially coextensive with each other—is described herein. The method includes inserting a thermally conductive blade between two adjacent edges of the first and second panes of optically transmissive material; and lifting an adverse flow stagnation zone forward of the optical window by protruding the thermally conductive blade into the flow of fluid from an outer surface of the panes of the optical window.

Technologies are described herein for a drag recovery scheme using a boundary layer bypass duct system. In some examples, boundary layer air is routed around the intake of one or more of the engines and reintroduced aft of the engine fan in the nozzle duct in a mixer-ejector scheme. Mixer-ejectors mix the boundary layer flow to increase mass flow.

A rotorcraft is provided and includes a fuselage. The fuselage includes drag generating portions, a main rotor assembly and an auxiliary propulsor having an expected propulsion efficiency. The auxiliary propulsor is disposed to ingest boundary layer flows and in wake regions associated with the drag generating portions and is provided with a corresponding increase in the expected propulsion efficiency thereof.

A rotorcraft is provided and includes a fuselage. The fuselage includes drag generating portions, a main rotor assembly and an auxiliary propulsor having an expected propulsion efficiency. The auxiliary propulsor is disposed to ingest boundary layer flows and in wake regions associated with the drag generating portions and is provided with a corresponding increase in the expected propulsion efficiency thereof.

A profiled structure for an aircraft or turbomachine is elongated in a direction in which the structure has a length exposed to an airflow and includes serrations defined by successive teeth and depressions. The serrations may be transverse to a leading edge and/or a trailing edge of the profiled structure and in the direction of elongation. Along the profiled leading edge and/or profiled trailing edge, the successive teeth and depressions may extend only over a part of the length exposed to the flow. The amplitude and/or spacing of the teeth may vary monotonically except for the few teeth nearest each end of the part, with a remaining part of the length being smooth.

An ejector system for propelling a vehicle. The system includes a diffusing structure and a duct coupled to the diffusing structure. The duct includes a wall having openings formed therethrough and configured to introduce to the diffusing structure a primary fluid produced by the vehicle. An airfoil is positioned within the flow of the primary fluid through the openings to the diffusing structure.