Abstract: In a method of making a carbon fibre preform such as for use in the manufacture of a friction disc a compressible body of carbon fibre or carbon fibre precursor material is acted upon by compressing means to compress the body to a required thickness and then operated upon by means such as a barbed needle-punch needle for a stitching thread which penetrates substantially the whole thickness of the body whereby the compressed preform may be removed from action by the compressing means in a free-standing and compressed state. If the method uses carbon fibre precursor material, that is then subjected to carbonization.

Abstract: A method for the manufacture of a light-weight panel, e.g. for aircraft, comprising preparing a panel preform having a pair of surface members or skins (29, 30) separated and supported by an internal core (26-28) in which spaces or interconnected pores provide vents to an edge of the panel, the wall surface members and the core comprising fibrous material, which may be carbon fibre, and using a pyrolysis process such as CVD to form a pyrolyric matrix around the fibres within the fibrous material, there being a flow of gas through the vents during the pyrolysis process.

Abstract: An aircraft disc stack (1) comprises a plurality of interleaved stator and rotor discs (3,4) keyed respectively to a torque tube (5) and a wheel hub (not shown). The stack (1) further comprises bi-functional friction/load transmitting discs in the form of end stator discs (10,13). These discs (10,13) are subject to uneven loading because the non-friction surfaces (12,15) are in use compressed on areas less than the load bearing areas of the opposing friction faces (11,14). This can lead to premature disc failure and in the past load spreader plates have been used to distribute loading over these areas to minimize the risk of failure. In this invention portions of the load bearing areas of non-friction surfaces (12,15) are toughened ie: material underlying these surfaces is toughened, to increase their resistance to deformation, fracture and/or wear thereby removing the need for additional load spreader plates which were hitherto required.

Abstract: Method of fabricating a multi-ply carbon fibre fabric, preform or composite material from a layer of unidirectionally aligned carbon fibres of ultra-high modulus and a layer of low modulus carbon fibre comprising the steps of: arranging in superimposed relationship the layer of unidirectionally aligned carbon fibres of ultra-high modulus and the layer of low modulus carbon fibres so that at least a substantial number of the fibres of low modulus are disposed transversely of the fibres of the ultra-high modulus fibre layer, and connecting the two layers by interlacing fibres of the layer of low modulus fibres with those of the layer of ultra-high modulus fibres by needle-punching using felting needles orientated and configured so that their barbs snag only the low modulus fibres during passage through the layers.

Abstract: A method for the manufacture of a light-weight panel, e.g. for aircraft, comprising preparing a panel preform having a pair of surface members or skins separated and supported by an internal core in which spaces or interconnected pores provide vents to an edge of the panel, the wall surface members and the core comprising fibrous material, which may be carbon fiber, and using a pyrolysis process such as CVD to form a pyrolytic matrix around the fibers within the fibrous material, there being a flow of gas through the vents during the pyrolysis process.

Abstract: A sheet of parallel carbon or carbon-precursor filaments is supported by a carrier sheet of fugitive backing material and needle punched. The fugitive backing material is subsequently destroyed leaving displaced or broken portions of the filaments entangled together to provide a stable sheet for composite manufacture, particularly for reinforcement of a carbon-carbon composite.