A method of micro-texturing a surface is disclosed. The method includes printing an etchant onto a substrate surface and forming a micro-texture on the substrate surface by removing material from the substrate surface.

A method of micro-texturing a substrate surface is disclosed, including printing a maskant on the substrate surface to define exposed surface zones on the substrate surface. The method further includes forming a micro-texture on the substrate surface by removing material from the exposed surface zones, and removing the maskant from the substrate surface.

In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each riblet of the periodic riblets of the second portion of the physical object is depressed below a plane of the smooth surface of the first portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.

In one embodiment, a method for reducing drag includes forming first periodic riblets on a smooth surface of a physical object and forming second periodic riblets on the smooth surface of the physical object. The method further includes generating a flow over the first and second periodic riblets of the physical object. Each first periodic riblet comprises a first transition region at a first end of each first periodic riblet and a second transition region at a second end of each first periodic riblet. Each second periodic riblet comprises a first transition region at a first end of each second periodic riblet and a second transition region at a second end of each second periodic riblet. Each second transition region at the second end of each first periodic riblet overlaps each first transition region at the first end of each second periodic riblet. A length of each riblet of the first and second periodic riblets runs parallel to a direction of the flow.

An exemplary aircraft includes a wing positioned below a vertical rotor, the wing extending to an outboard end, and an anhedral winglet extending from the outboard end through an angular transition to a tip, the anhedral winglet having an external surface exposed to the rotor downwash and the external surface is contoured to generate local wing lift in response to the rotor downwash.

An applicator for application onto and embossing microprofiling of a fluidic medium on a substrate, in particular in the aerospace sector, and a corresponding application device having such an applicator. The applicator has a circumferentially moving die that has an embossing profile, a press for the die and a stabilizing device, in particular a hardening device, for the applied medium. In addition, the applicator has a hollow support body, surrounded by the die at a distance forming a gap, the press being arranged in the gap. The application device has, in addition to the applicator, a handling device for a relative movement between the applicator and a workpiece.

Methods, apparatus, and articles of manufacture to extend a leading-edge vortex of a highly-swept wing aircraft wing are disclosed. An example apparatus includes a shoulder wing coupled to a fuselage of an aircraft above a highly-swept wing of the aircraft, the shoulder wing operative in a first position to extend a leading-edge vortex spanwise along the highly-swept wing of the aircraft.

A coating apparatus for the reduction of aerodynamic noise and vibrations. The coating apparatus is configured to include a group of fibrillar structures, wherein each fibrillar structure is configured with a diverging tip so that the coating reduces the size of and shifts downstream, a separation bubble, and modulates large-scale recirculating motion. Each fibrillar structure can be configured as a cylindrical micropillar. The group of fibrillar structures can be configured as a group of uniformly distributed cylindrical micropillars (e.g., one or more micropillar arrays). The surface coating is effective in reducing the separation bubble and displacing the separation bubble downstream. The coating facilitates a reduction in noise (e.g., aerodynamic noise) and vibrations due to the reduction in the size of the separation bubble.

A riblet film for reducing the air resistance of aircraft, comprising a suspension with magnetic particles enclosed therein. Depending on the pattern of a magnetic field acting on the riblet film, the magnetic field that is acting can be made visible, at least in certain regions, by changing the orientation of the magnetic particles. The riblet film allows an inspection of the aircraft structure located under the riblet film through the riblet film.

An engine nacelle is provided for an aircraft. The engine nacelle comprises: an inlet for receiving an air flow to generate a thrust force for the aircraft; a lip portion positioned at the inlet and surrounding the inlet; and at least one strake provided on a surface of the engine nacelle.