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 sheet laminate is utilised in the manufacture of a combustion chamber for a gas turbine engine. The laminate has passages therethrough, which connect with ambient atmosphere via holes. The arrangement creates local relatively thick portions or lands which cause stress concentrations along the passages and lines of holes. Therefore pockets are machined in the rear face of each land, so as to reduce the differences in thickness of the laminate and thereby ensure the more even distribution of stresses.

Abstract: Sheet metal plate has grooves formed in a side, by the electro chemical/photo resist method. Holes are formed in the same way, in the groove bottoms and pass through the metal thickness. In order to ensure that the holes have substantially parallel, dimensionally accurate walls, the sheet thickness to hole diameter ratio, is effectively reduced by first forming the holes to half depth in one side of the sheet, then forming grooves in the same side of the sheet in which the half holes are formed, so as to remove the half holes but leave depressions in the groove bottom at the positions where the half holes had been previously formed, then forming the hole proper for the holes by removing the metal from the opposite side of the sheet.