Abstract: Apparatus for making a soundproof lining for a gas pipe, in particular for a turbojet fan jet, of the type including a multiplicity of thin, perforated panels juxtaposed by tiling, as well as an intermediate layer between the wall of the pipe and each of said panels to delimit with said perforated panel a multiplicity of resonant acoustical cavities in which the acoustical vents consist of the ports in the perforated panel. According to the invention, in order to make the tubular vents, each perforated panel has a short, tubular sleeve at right angles to each port and located on its face opposite the wall of the pipe.

Abstract: Soundproof lining for a gas pipe, in particular for a turbojet fan jet, of the type including a multiplicity of thin, perforated panels juxtaposed by tiling, as well as an intermediate layer between the wall of the pipe and each of said panels to delimit with said perforated panel a multiplicity of resonant acoustical cavities in which the acoustical vents consist of the ports in the perforated panel. According to the invention, in order to make the tubular vents, each perforated panel has a short, tubular sleeve at right angles to each port and located on its face opposite the wall of the pipe.

Abstract: A rotor driven for an axial flow gas turbine engine compressor is formed as a composite structure of inner and outer skins with a core therebetween and a set of tensile reinforcing rings each located in a respective groove of a corrugated outer surface of the drum. In the completed drum the drum body is preferably under compressive prestress while the reinforcing rings are under tensile prestress.