Abstract: In a composite brake disc such as a carbon composite brake disc having reinforcement provided by layers of carbon fibre material, the drive region is provided with additional reinforcement to that of the friction region by laying or otherwise providing additional fibre reinforcement material substantially uniformly in the drive region.

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: A carbon-carbon composite friction disc is formed from two or more carbon-based structural components secured together by an interface layer which is not itself a structural member but is fusion-bonded to both of the structural components to secure them together. The interface layer may be of metallic material such as a brazing compound, or may be of non-metallic material such as pitch.

Abstract: A load-bearing thermal insulator, for example a brake piston thrust transmission element, which comprises platelets or flakes of thermally insulating material dispersed in a metal matrix and oriented normal to the direction of heat flow so as to impede the flow of heat through the matrix in one direction.