Abstract: A stator assembly for a rotary machine having an array of wall segments for bounding a working medium flow path is disclosed. Various construction details which provide a sealing structure for the segments are developed. In one detailed embodiment, a removable seal retainer for a seal chamber bounded by wall segments traps a resilient seal member in the seal chamber. In one particular embodiment, a modular subassembly for the engine is an outer air assembly disposed in a fixture as the subassembly is assembled.