An aircraft nacelle includes a forward cruise inlet, a forward-cruise-inlet conduit coupled to the forward cruise inlet and operable to supply air from the forward cruise inlet to an engine housed by the aircraft nacelle, an inlet barrier filter, an inlet-barrier-filter compartment coupled to the inlet barrier filter, a plurality of gills coupled between the inlet-barrier-filter compartment and the engine and operable to be in an open state and a closed state, a filter-purge door coupled to the inlet-barrier-filter compartment and operable to be in a closed state and an open state. When the plurality of gills are in the closed state and the filter-purge door is in the open state, air from the filter-purge door flows from the inlet-barrier-filter compartment through the inlet barrier filter.

A system includes an engine cover covering a side-facing rotorcraft engine and having an opening and an ice protection member mounted on the engine cover between the opening and the engine, an area of the ice protection member smaller than an area of the opening. The ice protection member is configured to partially cover the opening to prevent ice having a particular size from entering into the engine and to allow air flow downstream into the engine.

An aircraft propulsion assembly, comprising a gas generator and two fans rotated by the gas generator and offset on either side of a vertical plane passing through the axis of said gas generator. The propulsion assembly comprises an air inlet sleeve comprising an inlet pipe oriented along a first axis that is substantially parallel and offset with respect to a longitudinal axis of the gas generator, the inlet pipe dividing into a supply pipe that is connected to an inlet opening of the gas generator and a discharge pipe configured such that particles ingested by the inlet pipe are discharged without entering the gas generator.

An air-inlet duct includes a particle separator and an agglomerator. The particle separator is configured to receive atmospheric air laden with particles and to direct the particles into a scavenge passageway while allowing the atmospheric air to move into a compressor passageway thereby reducing the number of particles that enter the compressor passageway. The agglomerator is configured to cause the particles to be attracted to one another and cluster together.

A gas turbine engine has a fairing and an air intake that includes an air inlet embedded within the fairing for supplying free stream atmospheric air to a gas generator.

An inlet particle separator system for an engine includes an inner flowpath section, an outer flowpath section, a splitter, a first electrostatic discharge device, and a second electrostatic discharge device. The outer flowpath section surrounds at least a portion of the inner flowpath section and is spaced apart therefrom to define a passageway having an air inlet. The splitter is disposed downstream of the air inlet and extends into the passageway to divide the passageway into a scavenge flow path and an engine flow path. The first electrostatic charge device is disposed between the air inlet and the splitter and is electrostatically charged to a first polarity. The second electrostatic charge device is disposed downstream of the first electrostatic charge device and is electrostatically charged to a second polarity that is opposite to the first polarity.

A centrifugal separator for removing particles from a fluid stream includes an angular velocity increaser configured to increase the angular velocity of a fluid stream, a flow splitter configured to split the fluid stream to form a concentrated-particle stream and a reduced-particle stream, and an exit conduit configured to receive the reduced-particle stream. An inducer assembly for a turbine engine includes an inducer with a flow passage having an inducer inlet and an inducer outlet in fluid communication with a turbine section of the engine, and a particle separator, which includes a particle concentrator that receives a compressed stream from a compressor section of the engine and a flow splitter. A turbine engine includes a cooling air flow circuit which supplies a fluid stream to a turbine section of the engine for cooling, a particle separator located within the cooling air flow circuit, and an inducer forming a portion of the cooling air flow circuit in fluid communication with the particle separator. A method of cooling a rotating blade of a turbine engine having an inducer includes directing a cooling fluid stream from a portion of turbine engine toward the rotating blade, separating particles from the cooling fluid stream by passing the cooling fluid stream through a inertial separator, accelerating a reduced-particle stream emitted from the inertial separator to the speed of the rotating blade, and orienting the reduced-particle stream by emitting the reduced-particle stream from the inertial separator into a cooling passage in the inducer.

In one example embodiment, a filter condition measurement device features an engine data repository, one or more sensor units, and a measurement unit. The measurement system is configured to identify a first flow value corresponding to a sensed engine power value from the engine data repository, determine a filter coefficient for the filter as a function of the first flow value and the sensed delta-pressure value; identify a second engine power value from the plurality of stored engine power values and a second flow value corresponding to the second engine power value; and determine a second delta-pressure value for the air filter as a function of the filter coefficient and the second flow value.

An engine inlet assembly includes an inlet duct having a first inlet duct leg and a second inlet duct leg, the first inlet duct leg and the second inlet duct leg extending toward a common inlet duct outlet located at an engine inlet. The first inlet duct leg and the second inlet duct leg are fixedly secured to an airframe of an aircraft at an air inlet. The duct outlet has a floating interface with the engine inlet.

One example of an engine mounted inlet plenum for a rotorcraft includes an inlet flange, an outlet flange and a plenum duct that connects the inlet flange and the outlet flange. The inlet flange, which defines an inlet to flow air into a barrier filtration system, is configured to be substantially aligned with a closed cowl door assembly of the rotorcraft. In some implementations, the plenum duct is configured to extend to an outer mold line (OML) of the rotorcraft such that the inlet flange is aligned with the OML. The outlet flange defines an outlet to flow air filtered by the barrier filtration system into an engine of the rotorcraft. The plenum duct allows air to flow from the inlet to the outlet.