Abstract: A tip shroud includes a pair of opposed, axially extending wings configured to couple to an airfoil at a radially outer end thereof. The tip shroud also includes a tip rail extending radially from the pair of opposed, axially extending wings. Tip shroud surface profiles may be of the downstream and/or upstream side of the tip rail, a leading Z-notch of the tip shroud, and/or downstream radially inner surface of a wing. The surface profiles may have a nominal profile substantially in accordance with at least part of Cartesian coordinate values of X and Y, and perhaps Z and a thickness, set forth in a respective table. The radially inner surface of the wing may define a protrusion extending along the radially outer end of the airfoil, the suction side fillet, and a radial inner surface of the wing to an axial edge of the wing.

Abstract: A tip shroud includes a pair of opposed, axially extending wings configured to couple to an airfoil at a radially outer end thereof. The tip shroud also includes a tip rail extending radially from the pair of opposed, axially extending wings. Tip shroud surface profiles may be of the downstream and/or upstream side of the tip rail, a leading Z-notch of the tip shroud, and/or a downstream radially inner surface of a wing. The surface profiles may have a nominal profile substantially in accordance with at least part of Cartesian coordinate values of X and Y, and perhaps Z and a thickness, set forth in a respective table. The radially inner surface of the wing may define a protrusion extending along the radially outer end of the airfoil, the suction side fillet, and a radial inner surface of the wing to an axial edge of the wing.

Abstract: A tip shroud includes a pair of opposed, axially extending wings configured to couple to an airfoil at a radially outer end thereof. The tip shroud also includes a tip rail extending radially from the pair of opposed, axially extending wings. Tip shroud surface profiles may be of the downstream and/or upstream side of the tip rail, a leading Z-notch of the tip shroud, and/or downstream radially inner surface of a wing. The surface profiles may have a nominal profile substantially in accordance with at least part of Cartesian coordinate values of X and Y, and perhaps Z and a thickness, set forth in a respective table. The radially inner surface of the wing may define a protrusion extending along the radially outer end of the airfoil, the suction side fillet, and a radial inner surface of the wing to an axial edge of the wing.

Abstract: A tip shroud includes a pair of opposed, axially extending wings configured to couple to an airfoil at a radially outer end thereof. The tip shroud also includes a tip rail extending radially from the pair of opposed, axially extending wings. Tip shroud surface profiles may be of the downstream and/or upstream side of the tip rail, a leading Z-notch of the tip shroud, and/or a downstream radially inner surface of a wing. The surface profiles may have a nominal profile substantially in accordance with at least part of Cartesian coordinate values of X and Y, and perhaps Z and a thickness, set forth in a respective table. The radially inner surface of the wing may define a protrusion extending along the radially outer end of the airfoil, the suction side fillet, and a radial inner surface of the wing to an axial edge of the wing.

Abstract: A method of modifying a shank of a turbine blade from an initial profile to an undercut profile includes removing a first portion of material from an underside of a downstream angel wing of the turbine blade. The downstream angel wing extends axially from a downstream cover plate of the shank. The method also includes removing a second portion of material from a generally axially-extending portion of the downstream cover plate adjacent a dovetail of the turbine blade.

Abstract: A turbine blade includes an airfoil that extends radially between a root end and a tip end, a platform coupled to the root end, and a shank that extends radially inwardly from the platform. The shank includes a downstream cover plate and a downstream angel wing that extends axially from the downstream cover plate. A portion of the downstream cover plate radially outward of the downstream angel wing defines an approximately linear profile. The turbine blade also includes a dovetail region that extends radially inwardly from the shank. A profile of a portion of the downstream cover plate radially inward of the downstream angel wing is recessed relative to the linear profile.

Abstract: A turbine blade includes an airfoil that extends radially between a root end and a tip end, a platform coupled to the root end, and a shank that extends radially inwardly from the platform. The shank includes a downstream cover plate and a downstream angel wing that extends axially from the downstream cover plate. A portion of the downstream cover plate radially outward of the downstream angel wing defines an approximately linear profile. The turbine blade also includes a dovetail region that extends radially inwardly from the shank. A profile of a portion of the downstream cover plate radially inward of the downstream angel wing is recessed relative to the linear profile.

Abstract: A method of modifying a shank of a turbine blade from an initial profile to an undercut profile includes removing a first portion of material from an underside of a downstream angel wing of the turbine blade. The downstream angel wing extends axially from a downstream cover plate of the shank. The method also includes removing a second portion of material from a generally axially-extending portion of the downstream cover plate adjacent a dovetail of the turbine blade.

Abstract: A turbomachine bucket may include an airfoil, a shank coupled to the airfoil, and an angel wing coupled to the shank, the angel wing having an axially extending tip sized to seal with a plurality of discouragers, each discourager having a different axial extent. Various methods for modifying an angel wing to accommodate different sized discouragers are also disclosed.

Abstract: A turbine portion for a gas turbine includes a second stage rotor disk having a forward surface, an aft surface, and a plurality of dovetail slots. Each of the plurality of dovetail slots includes an upstream side and a downstream side. A plurality of airfoils is coupled to the second stage rotor disk. Each of the plurality of airfoils includes a radial centerline and a blade dovetail having a dovetail skew axis mounted in a corresponding one of the plurality of dovetail slots. At least one of the plurality of dovetail slots and the blade dovetail of at least one of the plurality of airfoils includes at least one stress reducing backcut spaced at least between about 1.446-inches (3.673-cm) and about 3.200-inches (8.13-cm) from a plane intersecting the radial centerline. The plane is substantially normal to the dovetail skew axis.

Abstract: A turbomachine bucket may include an airfoil, a shank coupled to the airfoil, and an angel wing coupled to the shank, the angel wing having an axially extending tip sized to seal with a plurality of discouragers, each discourager having a different axial extent. Various methods for modifying an angel wing to accommodate different sized discouragers are also disclosed.

Abstract: A retention system for a plurality of turbine buckets located in respective mating slots in a turbine rotor wheel includes a plurality of first circumferentially-oriented retention slots formed in outer peripheral portions of the turbine wheel; a plurality of second circumferentially-oriented retention slots formed in wheel mounting portions of said buckets, the first and second circumferentially-oriented retention slots aligned to form an annular lockwire retention slot; and a lockwire located within the annular lockwire retention slot. A first surface feature on one or both of the turbine rotor wheel and one or more of said plurality of turbine buckets is adapted to engage a second surface feature on the lockwire for preventing rotation of the lockwire beyond predetermined limits.

Abstract: A blade tip of a turbine rotor blade for a gas turbine engine, the turbine rotor blade including an airfoil and a root portion for mounting the airfoil along a radial axis to a rotor disk inboard of a turbine shroud, a pressure sidewall and a suction sidewall that join together at a leading edge and a trailing edge, the pressure sidewall and suction sidewall extending from the root portion to the blade tip, and a squealer tip cavity formed at the blade tip, the blade tip comprising: a trailing edge trench originating at the squealer tip cavity, wherein the trailing edge trench generally extends toward the trailing edge of the blade tip.

Abstract: A retention system for a plurality of turbine buckets located in respective mating slots in a turbine rotor wheel includes a plurality of first circumferentially-oriented retention slots formed in outer peripheral portions of the turbine wheel; a plurality of second circumferentially-oriented retention slots formed in wheel mounting portions of said buckets, the first and second circumferentially-oriented retention slots aligned to form an annular lockwire retention slot; and a lockwire located within the annular lockwire retention slot. A first surface feature on one or both of the turbine rotor wheel and one or more of said plurality of turbine buckets is adapted to engage a second surface feature on the lockwire for preventing rotation of the lockwire beyond predetermined limits.

Abstract: A blade tip of a turbine rotor blade for a gas turbine engine, the turbine rotor blade including an airfoil and a root portion for mounting the airfoil along a radial axis to a rotor disk inboard of a turbine shroud, a pressure sidewall and a suction sidewall that join together at a leading edge and a trailing edge, the pressure sidewall and suction sidewall extending from the root portion to the blade tip, and a squealer tip cavity formed at the blade tip, the blade tip comprising: a trailing edge trench originating at the squealer tip cavity, wherein the trailing edge trench generally extends toward the trailing edge of the blade tip.