Airfoil with cooling passage circuit through platforms and airfoil section

A gas turbine engine comprising:

• a compressor section;
• a combustor in fluid communication with the compressor section;
• and
• a turbine section in fluid communication with the combustor,
• the turbine section having a turbine airfoil that includes
• an airfoil section having an airfoil wall defining a leading end, a trailing end, and first and second sides joining the leading end and the trailing end, the first and second sides spanning in a longitudinal direction between first and second ends, the airfoil wall circumscribing an internal core cavity,
• first and second platforms attached, respectively, with the first and second ends, and
• a cooling passage circuit extending in the first platform, the airfoil section, and the second platform, the cooling passage circuit including
• a first plenum in the first platform, the first plenum extending adjacent the first side of the airfoil wall, adjacent the trailing end, and adjacent the second side of the airfoil wall,
• a skincore passage embedded in the first side of the airfoil wall and extending longitudinally,
• a first connector passage longitudinally spaced from the internal core cavity so as to extend around the internal core cavity, the first connector passage connecting the first plenum with the skincore passage,
• a second plenum in the second platform, the second plenum extending adjacent the first side of the airfoil wall, adjacent the trailing end, and adjacent the second side of the airfoil wall, and
• a second connector passage connecting the skincore passage with the second plenum.