A turbine assembly for a gas turbine engine, the turbine assembly comprising: a casing having an inner surface and extending circumferentially about an axial centerline , the casing defining a radially outer boundary of the turbine assembly; a disk positioned coaxially within the casing , the disk having a rim, the rim of the disk defining a perimeter of the disk ; a row of circumferentially adjacent turbine stator vanes extending radially inward from the inner surface of the casing ; a row of circumferentially adjacent turbine rotor blades extending radially outward from the perimeter of the disk , the row of blades positioned adjacent the row of vanes , wherein each blade in the row of blades includes an airfoil , each airfoil having opposite pressure and suction sides extending radially along a blade span ( s b ) from a blade root to a blade tip , the blade span ( s b ) including a plurality of blade span locations (SL), each blade span location (SL) corresponding to a fraction of the blade span ( s b ), wherein each airfoil defines a chord ( c ) at each blade span location (SL), the chords ( c ) extending axially between opposite leading and trailing edges of the airfoil , and wherein the chords ( c ) in a mid-span region ( s mid ) of each blade are shorter than the chords ( c ) in a span region (s 1 ) adjacent the blade root and a span region (s 2 ) adjacent the blade tip , wherein each blade has a stagger angle (λ) within a range of 10° to 80°, characterized in that the shorter chord length in the mid-span region of each blade is such that each blade has a Zweifel coefficient within a range of 1.2 to 1.3. a casing having an inner surface and extending circumferentially about an axial centerline , the casing defining a radially outer boundary of the turbine assembly; a disk positioned coaxially within the casing , the disk having a rim, the rim of the disk defining a perimeter of the disk ; a row of circumferentially adjacent turbine stator vanes extending radially inward from the inner surface of the casing ; a row of circumferentially adjacent turbine rotor blades extending radially outward from the perimeter of the disk , the row of blades positioned adjacent the row of vanes , wherein each blade in the row of blades includes an airfoil , each airfoil having opposite pressure and suction sides extending radially along a blade span ( s b ) from a blade root to a blade tip , the blade span ( s b ) including a plurality of blade span locations (SL), each blade span location (SL) corresponding to a fraction of the blade span ( s b ), wherein each airfoil defines a chord ( c ) at each blade span location (SL), the chords ( c ) extending axially between opposite leading and trailing edges of the airfoil , and wherein the chords ( c ) in a mid-span region ( s mid ) of each blade are shorter than the chords ( c ) in a span region (s 1 ) adjacent the blade root and a span region (s 2 ) adjacent the blade tip , wherein each blade has a stagger angle (λ) within a range of 10° to 80°, characterized in that the shorter chord length in the mid-span region of each blade is such that each blade has a Zweifel coefficient within a range of 1.2 to 1.3. <EOS>