Abstract: A fixed geometry duct defining a gas turbine engine exhaust nozzle includes a plurality of circumferentially adjoining flat triangular facets and coaxial first and second openings at opposite ends thereof. A method of making the duct includes scribing a plurality of lines on a flat sheet metal plate to define the facets, and bending the plate at each of the lines to form the duct.

Abstract: An exhaust nozzle for a gas turbine engine includes converging and diverging nozzles joined together at a throat and attached to a frame. An injection slot is disposed at the throat in flow communication with a transition duct for channeling injection air therethrough as controlled by an injection valve for fluidically varying throat area for exhaust gases discharged through the exhaust nozzle.

Abstract: An elastic seal includes a longitudinally extending elastomeric seal member with a continuous sealing surface and a longitudinally extending structural support member having at least one section with fingers extending transversely from the section with slots between the fingers. Each of the fingers is entirely embedded within the elastomeric seal member near the continuous elastomeric sealing surface. The fingers are preferably articulated downward in a direction normal to the sealing surface and together with the rest of the support member are preferably made of a spring material such as a flexible material such as a springy sheet metal. The elastomeric seal and structural members may be continuous bands with continuous metallic band with the fingers extending transversely from the metallic band. The continuous metallic and elastomeric bands may be annular, rectangular, ellipsoid, or have some other shaped cross-section.