Anti-icing stacks for protecting an aerodynamic surface are described. In some embodiments, an anti-icing stack includes an anti-icing layer, an elastomeric erosion protection layer, and an additional layer. The erosion protection layer is disposed between the anti-icing layer and the additional layer. The additional layer has a thickness greater than the thickness of the erosion protection layer and a tensile modulus of no more than the tensile modulus of the erosion protection layer. The additional layer may be a foam adhesive layer.

According to one implementation, a propulsion system includes a rotor, a motor and an anti-icing mechanism. The rotor has blades. The motor rotates the rotor. The anti-icing mechanism deices the blades using heat generated by driving of the motor. Further, according to one implementation, an aircraft includes the above-mentioned propulsion system. Further, according to one implementation, an anti-icing method of a rotor having blades includes deicing the blades using heat generated by driving of a motor for rotating the rotor.

An injector head for an anti-icing system may comprise a body configured to receive a pressurized gas, wherein the body is configured to provide the pressurized gas through a bulkhead into an interior volume of a D-duct, a first nozzle configured to generate a first flow of a first portion of the pressurized gas, a second nozzle configured to generate a second flow of a second portion of the pressurized gas, and a third nozzle configured to generate a third flow of a third portion of the pressurized gas, wherein the first nozzle is located at a distal end of the body relative to the bulkhead, and wherein a first hydraulic diameter of the first nozzle is less than each of a second hydraulic diameter of the second nozzle and a third hydraulic diameter of the third nozzle.

An injector head for an anti-icing system may comprise a body configured to receive a pressurized gas, wherein the body is configured to provide the pressurized gas through a bulkhead into an interior volume of a D-duct, a first nozzle configured to generate a first flow of a first portion of the pressurized gas, a second nozzle configured to generate a second flow of a second portion of the pressurized gas, and a third nozzle configured to generate a third flow of a third portion of the pressurized gas, wherein the first nozzle is located at a distal end of the body relative to the bulkhead, and wherein a first hydraulic diameter of the first nozzle is less than each of a second hydraulic diameter of the second nozzle and a third hydraulic diameter of the third nozzle.

Ice accumulation and shedding mitigation devices associated with sensor probes extending into a stream of air entering an aircraft engine are provided. An exemplary device comprises a wedge-shaped blade configured to be exposed to the stream of air and disposed upstream of the sensor probe. The wedge-shaped blade has two faces meeting at a leading edge oriented to face the stream of air.

A surface texture includes a three-dimensional structure, a cross-section of which includes a first serration and a second serration. The first serration has a first peak having a height measured from a base of the three-dimensional structure to a top of the first serration. A valley is formed in between the first serration and the second serration, where the valley has a length measured from a base of the first serration to a base of the second serration. The first serration also has a vertex angle that forms the first peak. A coating that covers at least a portion of the valley, where the valley is designed to remain free of frost.

An assembly is provided for an aircraft propulsion system. This aircraft propulsion system assembly includes an aircraft propulsion system and a microwave system. The aircraft propulsion system structure includes an exterior surface, an internal cavity and a susceptor thermally coupled to the exterior skin and within the internal cavity. The microwave system is configured to direct microwaves to the susceptor for melting and/or preventing ice accumulation on the exterior surface.

An airfoil is provided that includes an exterior substrate surface, and a coating layer adjacent to the exterior substrate surface. The coating layer has an icephobic coating composition that includes a first polymer, a second polymer that is a fluoropolymer, an isocyanate, and a curative. The coating layer is bonded to the airfoil via an intermediate adhesive layer. The coating layer has a bottom surface, and at least one of the exterior substrate surface and the bottom surface has an RMS surface roughness of at least about 1 micron or greater before the coating layer is bonded to the exterior substrate surface.

An airfoil is provided that includes an exterior substrate surface, and a coating layer adjacent to the exterior substrate surface. The coating layer has an icephobic coating composition that includes a first polymer, a second polymer that is a fluoropolymer, an isocyanate, and a curative. The coating layer is bonded to the airfoil via an intermediate adhesive layer. The coating layer has a bottom surface, and at least one of the exterior substrate surface and the bottom surface has an RMS surface roughness of at least about 1 micron or greater before the coating layer is bonded to the exterior substrate surface.

Provided is an icephobic coating composition comprising an epoxy resin comprising poly(phenyl glycidyl ether)-co-formaldehyde and a curing agent; a fluoro-substituted poly(alkyl siloxane) resin; and a solvent mixture comprising a first solvent with Hansen solubility parameters of 14≤δ.sub.D≤17, 6≤δ.sub.P≤13, and 4≤δ.sub.H≤8; and a second solvent with Hansen solubility parameters of 16≤δ.sub.D≤19, 4≤δ.sub.P≤9, and 11≤δ.sub.H≤15. Further provided is a coated filter comprising a porous medium having an upstream surface and a downstream surface, in which at least the upstream surface has a coating formed from the coating composition. Coated articles and methods of forming coated articles and inhibiting ice formation also are described.