Abstract: Methods and systems for operating a gas turbine engine are provided. A health parameter for the gas turbine engine is monitored at a health evaluation device via a first instrument, the health evaluation device being communicatively coupled to a communication link established between a controller, associated with the gas turbine engine, and a second instrument which provides the controller with an operation parameter indicative of an operating condition of the gas turbine engine. The health parameter is compared to a predetermined threshold. When the health parameter is beyond the predetermined threshold, a signal is injected into the communication link to produce a predetermined value for the operation parameter to elicit a health response from the controller associated with the predetermined value.

Abstract: A two-stage high pressure turbine includes a second stage blade having an airfoil with a profile substantially in accordance with at least an intermediate portion of the Cartesian coordinate values of X, Y and Z set forth in Table 2. The X and Y values are distances, which when smoothly connected by an appropriate continuing curve, define airfoil profile sections at each distance Z. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape.

Abstract: Methods and systems for operating a gas turbine engine are provided. A health parameter for the gas turbine engine is monitored at a health evaluation device via a first instrument, the health evaluation device being communicatively coupled to a communication link established between a controller, associated with the gas turbine engine, and a second instrument which provides the controller with an operation parameter indicative of an operating condition of the gas turbine engine. The health parameter is compared to a predetermined threshold. When the health parameter is beyond the predetermined threshold, a signal is injected into the communication link to produce a predetermined value for the operation parameter to elicit a health response from the controller associated with the predetermined value.

Abstract: A two-stage high pressure turbine includes a second stage blade having an airfoil with a profile substantially in accordance with at least an intermediate portion of the Cartesian coordinate values of X, Y and Z set forth in Table 2. The X and Y values are distances, which when smoothly connected by an appropriate continuing curve, define airfoil profile sections at each distance Z. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape.

Abstract: A nacelle exhaust nozzle having a deployable noise-reducing component is described. The noise-reducing component includes an annular perforated sleeve coinciding with the inner nacelle loft line and circumscribing a mixed exhaust gas flow exiting the nacelle. The annular perforated sleeve is radially spaced apart from of a displaceable wall of an inflatable envelope that is displaceable between a deployed position, wherein noise-reduction is active, and a retracted position, wherein noise-reduction is inactive. When the inflatable envelope is pressurized, portions of the displaceable wall project through openings in the perforated sleeve and into the exhaust gas flow to form a rough surface at the loft line which causes a reduction in noise level. The portions of the displaceable wall that project through the openings in the perforated sleeve when the inflatable enveloped is pressurized include a plurality of dimples formed on the inner wall and forming the rough surface.

Abstract: A combustor floating collar assembly having a floating collar disposed about an opening in an outer surface of a combustor liner. The floating collar is displaceable relative to the outer surface. A retention plate is attached to the outer surface of the combustor liner and traps the floating collar between the outer surface and the retention plate. At least a portion of the retention plate engages the floating collar and biases it toward the outer surface.

Abstract: A nacelle exhaust nozzle having a deployable noise-reducing component is described. The noise-reducing component includes an annular perforated sleeve coinciding with the inner nacelle loft line and circumscribing a mixed exhaust gas flow exiting the nacelle. The annular perforated sleeve is radially spaced apart from of a displaceable wall of an inflatable envelope that is displaceable between a deployed position, wherein noise-reduction is active, and a retracted position, wherein noise-reduction is inactive. When the inflatable envelope is pressurized, portions of the displaceable wall project through openings in the perforated sleeve and into the exhaust gas flow to form a rough surface at the loft line which causes a reduction in noise level. The portions of the displaceable wall that project through the openings in the perforated sleeve when the inflatable enveloped is pressurized include a plurality of dimples formed on the inner wall and forming the rough surface.

Abstract: A gas turbine engine has an engine core and an annular by-pass duct, within a surrounding nacelle. An exhaust nozzle of the nacelle includes a selectively deployable noise-reduction section on an inner surface thereof. The noise-reduction section includes an inflatable envelope comprising a fixed outer wall and a displaceable inner wall. At least projections on the inner wall are inwardly displaced when the envelope is pressurized and retracted radially outwardly when the envelope is de-pressurized. When the envelope is pressurized, the inner wall includes portions that project to form a rough surface on the inner surface of the nacelle exhaust nozzle. This thickens the boundary layer and reduces the speed of the gas flow at the outer radius of the nozzle, thus reducing the differential velocity with the ambient air, which reduces the gradient throughout the shear layer thus reducing the noise level of the engine.

Abstract: A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud may be provided in the form of an acoustic panel. The acoustic panel has a radially outwardly facing surface defining the radially inner flow boundary surface of the gaspath. The acoustic panel is mechanically fastened to the radially inner end of the struts.

Abstract: A turbine exhaust case comprises inner and outer annular shrouds defining therebetween an annular hot gaspath. A circumferential array of exhaust struts extends across the gaspath. The exhaust struts are mounted at one radial end thereof on a flexible strut mounting structure. The flexible strut mounting structure is radially deflectable relative to the outer and inner shrouds to accommodate thermal expansion of the exhaust struts during engine operation.

Abstract: A gas turbine engine has an engine core and an annular by-pass duct, within a surrounding nacelle. An exhaust nozzle of the nacelle includes a selectively deployable noise-reduction section on an inner surface thereof. The noise-reduction section includes an inflatable envelope comprising a fixed outer wall and a displaceable inner wall. At least projections on the inner wall are inwardly displaced when the envelope is pressurized and retracted radially outwardly when the envelope is de-pressurized. When the envelope is pressurized, the inner wall includes portions that project to form a rough surface on the inner surface of the nacelle exhaust nozzle. This thickens the boundary layer and reduces the speed of the gas flow at the outer radius of the nozzle, thus reducing the differential velocity with the ambient air, which reduces the gradient throughout the shear layer thus reducing the noise level of the engine.

Abstract: A turbine exhaust case comprises inner and outer annular shrouds defining therebetween an annular hot gaspath. A circumferential array of exhaust struts extends across the gaspath. The exhaust struts are mounted at one radial end thereof on a flexible strut mounting structure. The flexible strut mounting structure is radially deflectable relative to the outer and inner shrouds to accommodate thermal expansion of the exhaust struts during engine operation.

Abstract: A turbine exhaust case for a gas turbine engine has an outer shroud and an inner shroud concentrically defining therebetween an annular gaspath for channelling hot gases. A plurality of circumferentially spaced-apart turbine exhaust struts extends radially across the hot gaspath. The inner shroud may be provided in the form of an acoustic panel. The acoustic panel has a radially outwardly facing surface defining the radially inner flow boundary surface of the gaspath. The acoustic panel is mechanically fastened to the radially inner end of the struts.