Disclosed is a drone rotor cage. The drone rotor cage may include a motor housing, a plurality of spars, and a plurality of ribs. The plurality of spars may extend from the motor housing. Each of the plurality of spars may have a spar height and a spar thickness. The spar height may be greater than the spar thickness. Each of the ribs may extend from a respective one of the plurality of spars. Each of the plurality of ribs may have a rib height and a rib thickness. The rib height may be greater than the rib thickness. The plurality of spars and the plurality of ribs may define a space sized to allow a rotor to spin freely when the rotor cage is attached to a drone.

This disclosure relates to a method and resulting apparatus of applying a riblet sheet comprising a riblet film layer and a riblet liner layer on an airfoil surface. The method comprises applying the riblet film layer of the riblet sheet over the airfoil surface, peeling back at least a portion of the riblet liner layer from the riblet film layer to expose a portion of the riblet film layer, applying a attaching hardware or a non-textured surface film over at least a portion the riblet film layer portion; and applying the peeled back portion of the riblet liner layer over a portion of the attaching hardware.

An example method includes: forming a conductive layer on at least a portion of a surface of a substrate, where the substrate comprises a composite material of an aerodynamic structure, and where the conductive layer is configured to provide a conductive path to conduct an electric current generated by a lightning strike to an electrically-grounded location; depositing an insulating layer on the conductive layer; removing one or more portions of the insulating layer to form respective gaps in the insulating layer and expose corresponding one or more portions of the conductive layer; and forming a resistive-heater layer on the insulating layer such that the resistive-heater layer fills the respective gaps in the insulating layer and contacts the corresponding one or more portions of the conductive layer, such that when electric power is provided to the conductive layer, the electric power is communicated to the resistive-heater layer thereby generating heat therefrom.

An intentionally activated frangible bonding system comprises a frangible adhesive, adhesive primer, composite material matrix, and/or the like, having a polydispersion of at least one additive spread throughout the frangible bonding material. The additive degrades a bond provided by the frangible bonding material, upon application of a specific energy to the frangible bonding material. An energy emitter is configured to selectively direct the specific energy toward a structure or assembly comprising components bonded by the frangible bonding material to degrade the frangible bonding material bonding the components for disassembly.

A protective coating composition for providing protection to a component of a ram air turbine system in need thereof. The protective coating composition comprises an aqueous-soluble or alkaline-soluble polymer matrix, one or more compressible fillers, and one or more non-compressible fillers. The disclosure also provides a method for providing a protective coating onto components of a ram air turbine system in need thereof for providing indentation and scratch resistance thereto.

An airfoil that includes an airfoil body having a root and a tip, and convex and concave sides that extend between a leading edge and a trailing edge. The airfoil also includes at least a first cladding element that is attached to the airfoil body. The first cladding element includes a first portion and a second portion. The second portion is configured to separate from the first portion when the first cladding element encounters a force of at least a predetermined amount.

An example method includes: forming a conductive layer on at least a portion of a surface of a substrate, where the substrate comprises a composite material of an aerodynamic structure, and where the conductive layer is configured to provide a conductive path to conduct an electric current generated by a lightning strike to an electrically-grounded location; depositing an insulating layer on the conductive layer; removing one or more portions of the insulating layer to form respective gaps in the insulating layer and expose corresponding one or more portions of the conductive layer; and forming a resistive-heater layer on the insulating layer such that the resistive-heater layer fills the respective gaps in the insulating layer and contacts the corresponding one or more portions of the conductive layer, such that when electric power is provided to the conductive layer, the electric power is communicated to the resistive-heater layer thereby generating heat therefrom.

The present invention includes an apparatus for protecting an aerodynamic surface from erosion including a screen capable of being applied to a leading edge of the aerodynamic surface; and an erosion protection coating applied to the screen before or after the screen is applied to the leading edge, wherein the erosion protection coating protects the aerodynamic surface from erosion.

A spar for an airfoil comprises a core, e.g. a foam core, a central structural member extending through the core, an outer structural layer surrounding the core and central structural member and a plurality of yarns extending through the central structural member.

According to one aspect, an airfoil assembly for a gas turbine engine comprises a first end wall, a second end wall, an airfoil and a sheath. The first end wall has surfaces defining a first recess, and the second end wall has surfaces defining a second recess. The airfoil includes a first portion disposed in the first recess, a second portion disposed in the second recess, and a leading edge disposed between the first and second portions. The sheath is in contact with the first and second portions of the airfoil covering the leading edge between the surfaces defining the first and second recesses.