An aircraft propulsion system includes an engine. The propulsion system further includes an inlet having a forward cowl lip and an aft cowl lip. The forward cowl lip moves between retracted and deployed positions. The forward cowl lip is adjacent to the aft cowl lip when retracted. The forward cowl lip is spaced apart from the aft cowl lip when deployed. The forward cowl lip has a smaller radius of curvature than the aft cowl lip. The propulsion system further includes a controller coupled with the engine and inlet. The controller restricts the maximum thrust commanded position of the engine when the aircraft is on the ground and moving below a predetermined speed. The controller lifts the restriction when the aircraft is moving at at least the predetermined speed. The controller controls the inlet to deploy the cowl lip when the aircraft is on the ground.

A method for forming a fiber-reinforced thermoplastic acoustic panel may comprise: stacking plies of thermoplastic composite sheets to a first thickness to form a top sheet; stacking plies of thermoplastic composite sheets to a second thickness to form a backskin; staking plies of thermoplastic composite sheets to a third thickness to form a stiffening member; forming the top sheet in a first contour; forming the backskin in a second contour, the second contour being different from the first contour; forming the stiffening member comprising a shape having a plurality of peaks and troughs; bonding the stiffening member to the top sheet and the backskin; and perforating the top sheet.

A variable geometry inlet system of an aircraft engine includes an inlet duct. The inlet duct includes at least first and second sections moveable between extended and retracted positions such that the inlet duct defines a variable axial length of an inlet passage for selective flight conditions. The inclusion of acoustic treatment may assist in controlling noise.

An aerospace component, for example, used in a gas turbine engine, includes the following structurally-integrated layers: a metallic layer and a composite layer having reinforcing fibers embedded in a matrix material. The aerospace component can also include an insulating layer disposed between the metallic layer and the composite layer where the insulating layer has a thermal conductivity that is lower than a thermal conductivity of the composite layer.

An assembly for a gas turbine engine has: a fan case with a forward end, an aft end, and an inner surface extending from the forward end of the fan case to the aft end of the fan case; an acoustic liner having a forward end, an aft end, and an acoustic liner body that extends continuously from the forward end of the acoustic liner to the aft end of the acoustic liner; an inlet case located forward of the forward end of the fan case, the forward end of the acoustic liner being secured to the inlet case, and wherein the acoustic liner body is positioned against an inner surface of the inlet case and an inner surface of the fan case, and the aft end of the acoustic liner is secured to the fan case between the forward end and the aft end of the fan case.

A porous skin including strips and an acoustic attenuation panel. The porous skin (1) includes of strips (2) arranged transversely to a fluid flow (E) and which successively overlap each other laterally, each strip (2) upstream of said fluid flow (E) overlapping the downstream strip or strips (2), each of the strips (2) including at least one lateral edge comprising a contour defining a line with deviations, namely a broken line and/or a curved line, and the arrangement of the strips (2) and the contour or contours of their lateral edges being configured to form openings (11) between the strips (2) connecting an external face of the porous skin (1) to an internal face of said porous skin (1) and to prevent the fluid flow (E) from penetrating into said openings (11), the porous skin (1) thus being adapted to have sound waves pass through it while preventing the fluid flow (E) from passing through it.

A forward part of an aircraft propulsion unit nacelle, comprising an air intake lip, an acoustic panel, and a rigid connection between the acoustic panel and the air intake lip. The acoustic panel has a resistive surface and a back skin, and the rigid connection is formed between the air intake lip and the back skin of the acoustic panel to form a propagation path for forces between the air intake lip and the back skin. This configuration gives freedom from design constraints, which enables an increase in the acoustic treatment region toward the front of the nacelle. An aircraft propulsion unit comprising a nacelle having such a forward part is also provided.

An acoustic panel for an aircraft nacelle air intake comprising a resistive skin perforated by noise absorption holes and a core against which the resistive skin extends, wherein the resistive skin has a smooth visible face and a castellated rear face with alternating ribs and grooves. The noise absorption holes are formed exclusively in the grooves, i.e., in a zone where the skin is less thick, which enables the holes to have a diameter that is both greater than the thickness of the skin and small enough not to have any impact on drag. The mechanical strength of the resistive skin provided by the ribs ensures that the lesser thickness of the resistive skin in the grooves does not render the resistive skin overly flexible.

An optimized protection against ice on the inner and outer faces of an aircraft engine nacelle air intake with the air intake including an outer face and an inner face meeting at a line at the longitudinally extreme, called extremum line, an acoustic panel being installed on the inner surface of a part of the inner face. An elimination system based on vibration of the ice formed is put in place on at least a part of the outer face and an ice formation prevention system using a hot fluid is put in place on at least a part of the inner face and either an ice elimination system or an ice formation prevention system using a hot fluid is installed on the inner face and on the outer face, a marking line marking the boundary between the two systems.