Method for making an air cooled combustor

A method for fabricating a gas turbine engine combustor wall having a curved surface thereon for flow of cooling air film across the inner wall surfaces of a downstream wall portion of a combustor comprising the steps of:

• preforming an annular metal part having a curved end surface, coating said surface with photoresist material, preparing a transparency having a crosshatch grid thereon of continuously curved intersecting lines selected to correspond to the curvature of said end surface to project as a straight line grid thereon, positioning the surface and coated photoresist material thereon on an adjustable work platform, projecting the crosshatched curved grid pattern from said transparency against the photoresist material through an angle to cause the curved grid pattern lines of the phototransparency to be exposed as a uniform straight line grid pattern on the photoresist material, developing the exposed straight line grid pattern on the photoresist material, masking all areas of the coated curved surface except the exposed straight line grid pattern thereon, and thereafter etching the uniform straight line pattern into metal of the curved end surface to produce a uniform pattern of raised lands with straight edges across the curved end surface of the annular metal part for producing a uniform surface scrubbing action and cooling of the metal part during flow of the air film thereacross.