Abstract: An air intake structure for a nacelle of an aircraft is disclosed having an air intake lip with a U-shaped section open towards the rear, an acoustic panel that extends the air intake lip towards the rear and on an inner side, an outer panel extending the air intake lip towards the rear and on an outer side, and a rear strengthening frame fixed between the outer panel and the acoustic panel, where the rear strengthening frame partly defines an inner volume that is immediately in front of the rear strengthening frame. The air intake structure comprises an impact absorber element positioned in the inner volume and the impact absorber element assumes the form of a structure that is deformable during an impact and that is at least partially filled with a fluid. The impact absorber element is a flexible shroud filled with a pressurized gas.

Abstract: A production method for an acoustic panel comprising a step of producing a composite structure, a step of providing inserts, wherein each insert comprises a nozzle formed as a hollow cylinder with a through-bore and a cap comprising a base formed as a cylinder and a cover formed as a cone, and wherein the base is accommodated in the bore, a step of positioning the inserts in the composite structure by penetration of the cover into the composite structure so that the bore opens at one side and the other of the composite structure, a step of polymerizing during which the composite structure with the inserts is polymerized, a step of removing the caps, a first step of fixing a honeycomb structure to the polymerized composite structure, and a second step of fixing a rear skin to the honeycomb structure.

Abstract: A resistive skin shell for an acoustic panel or inner wall of an aircraft air intake, comprising an alternation, in a transverse direction, of perforated metal bands and of composite solid bands extending in a longitudinal direction. The perforated metal bands and the composite solid bands form a smooth outer face configured to be in contact with an aerodynamic stream, and a crenelated inner face. The composite solid bands have a thickness greater than the perforated metal bands. Since the perforations are provided in metal bands, which are intrinsically resistant to wear and erosion, the future proofing of the acoustic performance of the resistive skin is guaranteed. Since the composite solid bands, which are thicker, can ensure the mechanical strength of the skin, the thickness of the perforated metal bands can be reduced, allowing perforations with dimensions that are also reduced, having a lower impact on drag.

Abstract: An aircraft nacelle including a conduit rigidly connected to an air inlet and a conduit rigidly connected to an engine, a link between the conduit rigidly connected to the air inlet and the conduit rigidly connected to the engine. The link includes a sleeve that receives one end of a first conduit and is rigidly connected to a second conduit, and linking elements that link the sleeve and the first conduit and that are distributed about the entire circumference of the nacelle, each linking element having a threaded stem oriented in a radial direction and being configured to enable tightening from inside the first conduit.

Abstract: An anterior part of a nacelle of an aircraft propulsion unit. A rigidifying frame annular about a longitudinal axis of extension of the nacelle is at the rear end of the anterior part. An annular shield is in front of the rigidifying frame and connects an internal peripheral edge of the rigidifying frame to an internal structure. The shield has a portion extending towards the external panel beyond the internal peripheral edge of the rigidifying frame, the portion forming a non-zero angle with respect to the rigidifying frame to form a free space with respect to the rigidifying frame behind the portion. The shield can thus deform in the event of an impact of a foreign object entering through the air inlet lip, without the rigidifying frame itself being deformed, thereby absorbing all or some of the impact energy. A nacelle can have such an anterior part, and an aircraft can have such a nacelle.

Abstract: An acoustic panel comprising a cellular structure, such as a honeycomb structure, having cells that open at least onto a first frontal face of the structure. The panel comprises a capsular skin which is fastened to the first frontal face of the cellular structure next to a plurality of cells. The capsular skin including a continuous layer of material, in one piece, forming capsules that extend into the cellular structure. At least one channel is provided at the apex of each capsule for the passage of acoustic waves. Such a panel effectively attenuates the noise of aircraft engines, in particular, the low frequencies. It is extremely easy to manufacture industrially, the capsular skin being able to be obtained by molding with polymerization in situ, the polymerizable material then adhering to the cellular structure while it polymerizes.

Abstract: A strip-form acoustic material, the strip having a length in a longitudinal direction, a width in a transverse direction, a thickness and axial ends. At least one of the axial ends of the strip, in an end portion of the length of the strip, the strip of material is folded in a substantially transverse plane.

Abstract: A frost protection system for an aircraft engine nacelle, the nacelle comprising an inner shroud provided with at least one acoustic panel and an air intake lip forming a leading edge of the nacelle. The protection system comprises a heat exchanger device including at least one heat pipe configured to transfer heat emitted by a heat source to the at least one acoustic panel.

Abstract: A method for producing an alveolar soundproofing structure in which a portion of a membrane of a diaphragm including an acoustic outlet is inserted into a hole of a perforated membrane which covers a cell of the alveolar structure, and the diaphragm is pressed into the cell with the perforated membrane becoming deformed and is fixed at that location. It also relates to the alveolar structure. Such a method enables different types of diaphragms to be inserted into different configurations of cells and enables the diaphragm to be fixed therein, in accordance with the sound frequencies to be processed.

Abstract: A cellular sound insulation structure and associated aircraft, a cell of which is provided with a diaphragm which includes a membrane having at least one orifice passing through a thickness of the membrane, and at least one tube surmounting the orifice and extending from a face of the membrane into one compartment of the cell, the tube comprising a free end, forming an acoustic outlet, which is positioned at a distance (p) from the base cross section of the cell. Also, a method for manufacturing such a cellular sound insulation structure, as well as to a tool for inserting a diaphragm into a cell. Such a cellular structure makes it possible to treat a wider acoustic frequency spectrum, and its acoustic dimensioning as well as its manufacture are simplified.

Abstract: An aircraft nacelle comprising an air inlet, with a single fan cowling made of a single piece which extends over all the circumference of the fan. The fan cowling is borne by the air inlet and is mounted to be rotationally mobile about the axis of the nacelle relative to the air inlet, via a link and guiding arrangement comprising a circular rail and a runner capable of sliding along the circular rail. The fan cowling comprises one or more openings closed by hatches allowing access to the interior of the nacelle. The fan cowling has little susceptibility to being deformed both in flight and on the ground during maintenance operations. Furthermore, no pylon portion is needed in the zone of the fan cowling since the latter is not attached to the pylon.

Abstract: An acoustic panel for an aircraft nacelle includes, from a central axis of the nacelle to the exterior thereof, a resistive skin perforated with sound-absorbing micro-perforations, a first attenuation stage, a septum perforated with holes, a second attenuation stage, and a back skin configured to provide the mechanical strength of the acoustic panel. The septum is a planar wall having a thickness greater than that of the resistive skin, preferably greater than 4 mm. Such a panel is configured to attenuate several frequency ranges one of which being a low-frequency range, while optimizing the weight, the cost and the air intake functions. The thickness of the septum, the dimensions of the holes in the septum, the OAR of the septum and the height of the second attenuation stage are adjusted to match the mean attenuated low frequency to the vibration frequency of the aircraft engine.

Abstract: An aircraft engine air inlet lip takes an annular form about a longitudinal axis and delimits an air inlet stream, and includes: a wall having a U-shaped profile having an outer face oriented towards outside of the air inlet lip and an inner face oriented towards interior of the air inlet lip, an inner wall extending inside the wall between two zones of the inner face, so as to close an inner chamber delimited between the wall and the inner wall and filled with a gas, the inner wall having an upstream face oriented towards and a downstream face oriented away from the inner chamber, a fan configured to move the gas contained in the inner chamber, and at least one pipeline fixed to the upstream face and extending all around the air inlet lip and configured to be fed with a heat transfer fluid heated by a heat source.

Abstract: An assembly including two juxtaposed acoustic panels. Resistive faces of the acoustic panels are in the continuation of one another. A first resistive face extends as far as the first end wall of a first panel. The first end wall is in contact with a second end wall of a second panel in the region of the first resistive face and of the second resistive face. A connecting piece is interposed between the first end wall and the second end wall over a part of the length thereof so that the connecting piece does not extend as far as the first and second resistive faces. That makes it possible to form an acoustic cladding that is continuous, exhibiting no non-acoustic zone or reduced-acoustic zone at the junction between the acoustic panels of which it is formed. A nacelle of an aircraft propulsion unit is one application.

Abstract: An acoustic treatment panel including a porous acoustically resistive structure which includes at least one external layer which is in contact with the external environment and which has through holes, internal strips including several openings which communicate with the inside of the cells of the panel and connecting canals, interposed between the external layer and the internal strips, which ensure that the floor-section openings communicate with at least one through hole of the external layer.

Abstract: An anterior part of an aircraft propulsion assembly nacelle, having an air intake lip disposed at a front end and an outer panel, of which an outer face extends an outer part of the air intake lip. A front edge of the outer panel and a rear edge of the air intake lip are shaped so as to overlap radially and to nest so as to ensure a continuous surface between the outer surface of the outer part of the air intake lip and the outer face of the outer panel. Moreover, the front edge of the outer panel is connected to the rear edge of the air intake lip with no added rigid element. This permits a rigid connection while avoiding creating local irregularities on the outer surface of the nacelle, which irregularities might disrupt the flow of air around the nacelle, giving rise to additional drag.

Abstract: An anterior part of a nacelle of an aircraft propulsion assembly, which comprises an air intake lip, an outer panel extending an outer part of the air intake lip, an inner structure extending an inner part of the air intake lip, a front frame connecting the outer wall to the air intake lip or to the inner structure. The outer panel and the outer part of the air intake lip together form an outer wall of the anterior part. The front frame and the outer wall are connected to one another by assembly means located inside the anterior part. The anterior part constituted in this manner ensures laminar flow of the air on an outer surface of the anterior part and reduces drag. A nacelle of a propulsion unit, comprising an anterior part of this kind is also provided.

Abstract: An anterior part of a nacelle of a propulsion assembly of an aircraft, having an air intake lip and a front frame disposed at the rear of the air intake lip that connects an outer part to an inner part of the air intake lip. A de-icing duct is formed in front of the front frame. The front frame is shaped so that the de-icing duct has a main cavity and a thermal transition region formed behind the main cavity between an internal face of the outer part of the air intake lip and the front frame. The thermal transition region extends over a longitudinal dimension greater than its average radial dimension, the front frame forming, with respect to the internal face of the outer part of the air intake lip, an angle, measured longitudinally, of between ?20° and +10° over the majority of the thermal transition region.

Abstract: 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.

Abstract: An acoustic treatment panel in which each cell includes a plurality of conduits which extend from the porous acoustically resistive structure to the reflective layer of the acoustic treatment panel, each conduit including at least one opening set away from the porous acoustically resistive structure and configured to cause the inside and the outside of the conduit to communicate.