Patent ID: 7625172

Claim:
A method for manufacturing a vane cluster, the vane cluster comprising: a platform; a shroud; at least first and second airfoils extending between an outer face of the platform and an inner face of the shroud, each airfoil having a pressure side and a suction side, the pressure side of the first airfoil facing the suction side of the second airfoil; and a cooling passageway system, wherein: the cooling passageway system includes: at least one inlet in the shroud; at least one first feed passageway from the shroud to the platform through the first airfoil; at least one second feed passageway from the shroud to the platform through the second airfoil; a first platform cooling plenum to the pressure side of the first airfoil; a second platform cooling plenum to the suction side of the first airfoil; and first and second pluralities of outlet holes extending to first and second circumferential ends of the platform, the method comprising: manufacturing a casting by an investment casting process, the casting including precursors of the platform, shroud, first and second airfoils, first and second feed passageways, and first and second platform cooling plenums; and securing at least one cover over the first platform cooling plenum, wherein: the investment casting uses first and second feed cores to cast the first and second feed passageways and a single separate core for casting the first and second platform cooling plenums; and in the as-cast casting, the first platform cooling plenum precursor is open along an inboard surface of the platform precursor, but the second platform cooling plenum precursor is subsurface to said inboard surface.