Abstract: A method of designing an outer air seal for the turbine blades of a gas turbine engine utilizes a knowledge-based product model software program for generating a parametric, three-dimensional, geometric model of the air seal. The product model software program is embodied in a knowledge-based engineering system. The model is created by the program through user selection of various structural feature options available for the air seal. The product model software program uses its internal knowledge base of configuration dependent parameter relationships and rules to design the model. Various types of analyses may then be run to validate the model. The model may be changed, if necessary, as a result of the analyses. The air seal model output from the product model software program is in a file format that defines the topology and dimensions of the geometry of the air seal.

Abstract: A shroud for a rotor assembly is provided comprising a mounting ring, an aft seal ring, a forward seal ring, and a blade outer air seal. The mounting ring is fixed within the casing surrounding the rotor assembly, and includes a first attachment apparatus. The blade outer air seal includes a plurality of body segments. Each body segment includes a first face, a second face, a plurality of passages for receiving cooling air disposed between the faces, a second attachment apparatus, and a post for biasing each the body segment in contact with the aft seal ring. The first and second attachment apparatus cooperate to suspend the blade outer seal segments in close proximity to the rotor assembly.

Abstract: A shroud for supporting the vanes in the hot sections of a gas turbine engine is comprised of composite segments retained in a metal ring. The metal ring has a positive coefficient of expansion, while the segments have a zero (or much smaller) coefficient. When the ring is heated and grows, it carries the segments with it, so that there is an apparent corresponding growth of the segments.

Abstract: An external fairing flap (26) is provided with an hydraulic spring (42, 44) for causing the external flap (26) to follow the motion of an exhaust nozzle control flap (18). The external flap (26) is hinged (32) at the leading edge thereof, and contacts the control flap (18) via corresponding rubstrips (40, 36) at the flap trailing edges (28, 38).