Abstract: An investment mould process for forming a cast member is described. The process comprises forming a precursor casting (12) from a master mould (10). The master mould (10) has an internal surface (16) defining a space (14) in which the precursor casting (12) can be formed. The surface (16) defines a location indentation (20) to provide a corresponding location projection (3) on the precursor casting (12). A holding member (22) can be inserted into the location projection (3) to hold an internal member (17A, 17B).

Abstract: An investment mould process for forming a cast member is described. The process comprises forming a precursor casting (12) from a master mould (10). The master mould (10) has an internal surface (16) defining a space (14) in which the precursor casting (12) can be formed. The surface (16) defines a location indentation (20) to provide a corresponding location projection (3) on the precursor casting (12). A holding member (22) can be inserted into the location projection (3) to hold an internal member (17A, 17B).

Abstract: An investment mould process for forming a cast member is described. The process comprises forming a precursor casting (12) from a master mould (10). The master mould (10) has an internal surface (16) defining a space (14) in which the precursor casting (12) can be formed. The surface (16) defines a location indentation (20) to provide a corresponding location projection (3) on the precursor casting (12). A holding member (22) can be inserted into the location projection (3) to hold an internal member (17A, 17B).

Abstract: An investment mould process for forming a cast member is described. The process comprises forming a precursor casting (12) from a master mould (10). The master mould (10) has an internal surface (16) defining a space (14) in which the precursor casting (12) can be formed. The surface (16) defines a location indentation (20) to provide a corresponding location projection (3) on the precursor casting (12). A holding member (22) can be inserted into the location projection (3) to hold an internal member (17A, 17B).

Abstract: Shrouds (40) surrounding a stage of turbine blades (44) are cooled by a compressor airflow which is led to the downstream end of the shrouds before contacting them. The airflow passes through apertures (56) in plates (50) then over the shrouds (40) in an upstream direction, to exit from apertures (62) in the shrouds (40) in parallel with and in the same direction as the gasflow. Airflow needed is reduced relative to prior art needs, resulting in improved engine efficiency, and ejection of the air does not disturb the gasflow.

Abstract: A perforate laminated material suitable for use in the manufacture of combustion chambers for gas turbine engines comprises two sheets bonded together, each sheet having a plurality of perforations, the laminated material being formed with internal channels which interconnect the perforations in the abutting sheets, the contact area between the two sheets being in the range 18% to 60% of the surface area of one side of one of the sheets and the ratio between the number of perforations per unit area in the sheets being in the range 2:1 to 10:1 in use the sheet having the larger number of perforations being adjacent a relatively hot gas stream.

Abstract: A material suitable for making combustion chambers for gas turbine engines comprises at least two abutting sheets of perforated material, the perforation being out of alignment and interconnected by a series of channels formed on one or both of the abutting surfaces of abutting sheets. The total cross-sectional area of the perforations in at least one sheet is at least double the total cross-sectional area of the perforations in the remaining sheets or sheets per unit area.