An aircraft control system and method to optimize aircraft control based on noise abatement volumes. A noise abatement component computes optimal flight and engine control based on a line-of-sight distance to minimize direct operating cost (DOC) while complying with community noise regulations.

An acoustic attenuation panel for a propulsion unit including a nacelle and a turbojet engine includes a cellular core disposed between an inner skin and an outer skin, called acoustic skin, the acoustic skin including a plurality of acoustic apertures, the acoustic apertures being inclined, at a non-zero inclination angle (β) relative to the direction normal to the acoustic skin, upstream with respect to the flow direction of the air or gas flow to which the panel is intended to be subjected under normal operating conditions, that is to say upstream of the propulsion unit when the panel is mounted in such a unit.

A sound attenuation panel that includes an incident wall and a frame unit connected to the incident wall. The incident wall defines an aperture therethrough. The frame unit includes multiple spoke members spaced apart from one another and radially extending from one or more central hub openings of the frame unit. The one or more central hub openings align with the aperture of the incident wall. The frame unit defines channels between adjacent pairs of the spoke members. The channels fluidly connect to the one or more central hub openings. The frame unit is configured to receive sound waves into the central hub opening through the aperture of the incident wall to dissipate the sound waves through the channels between the spoke members.

Disclosed is an electrically driven ducted fan engine, comprising a housing with an inner housing wall, defining a substantially cylindrical inner space and a longitudinal axis, an inlet opening, a rotor with a multitude of rotor blades positioned in the inner space of the housing downstream of the inlet opening, a stator assembly with a multitude of guide vanes extending from a radially central region of the inner space to the inner wall of the housing, and an exhaust opening provided in the housing downstream of the stator assembly, an interstage region defined between the rotor and the stator assembly, a guide vane region defined in which guide vanes extend to the inner wall of the housing and an exhaust section, wherein in at least one of the interstage region, the guide vane region and the exhaust region, acoustic liners are provided to the housing.

This present disclosure relates generally to propulsion systems and, more particularly, to adaptive ducted fan propulsion systems for use with aircraft such as unmanned aerial vehicles. Embodiments of ADF systems in accordance with the present disclosure feature automatic, fast operation, increase the intake section of the air mass fed to a propeller, and can increase thrust by 35%-40% as compared to existing ducted fans.

A cascade for a thrust reversal device intended to be mounted on a turbomachine of an aircraft, the cascade including first partitions extending in a first direction, second fixed partitions extending in a second direction orthogonal to the first direction, and a frame inside which the first and second partitions extend, the frame including at least two fixed walls extending according to the first direction, and at least one part of each first partition extending between two second partitions. At least one first partition is mobile according to the second direction between a first position wherein the first partition is distant, in the second direction, from the fixed walls to form a plurality of resonating cavities with the first partitions and/or the fixed walls, and a second position wherein the one first partition is in contact with a fixed wall or another first partition.

An acoustic panel including first and second cellular structures, the first cellular structure including a set-back portion to form a recess dimensioned to accommodate the second cellular structure such that first faces of the first and second cellular structures, in contact with a first, acoustically resistive layer, are coplanar and that first edge faces of the first and second cellular structures are coplanar when the second edge face of the second cellular structure is in contact with the set-back portion. By virtue of the set-back portion, the first and second cellular structures are positioned correctly with respect to one another, thus contributing to an optimization of the acoustic treatment.

According to an aspect, an ejector member includes an annular member; a vent arranged at the annular member, the vent having an inlet at a first surface of the annular member, the vent further having an outlet arranged radially inward from a second surface of the annular member; and a vane extending radially inward from the second surface of the annular member.

An acoustic panel for an aircraft providing noise attenuation over a wide frequency band by combining two resonators, and acoustic panel manufacturing method. The acoustic panel includes a rear skin, a cellular structure, an intermediate layer including perforations, a cellular structure, a cellular structure and a resistive skin including perforations. The acoustic panel combines quarter-wave resonators with Helmholtz resonators to provide noise attenuation over a wide frequency range.

Disclosed are laminates comprising a carbon fiber reinforced polymer sheet and a layer of polysilazane and methods for producing such laminates.