Cooling air inlet configuration for a blade root

An improved attachment air inlet configuration for a turbine blade comprises a plurality of inlets 39 in the blade root, each inlet being non-circular and having a major axis substantially normal to a root portion centre plane 41. This arrangement reduces attachment rib concentrated stresses in highly loaded, single crystal turbine blades that cause cracking in conventional blade inlet configurations. It also desensitizes rib concentrated stresses to variations in secondary crystal orientation, permitting highly loaded single crystal blades to have random secondary crystal orientation for lower cost, or seed with any secondary orientation needed to solve other blade or manufacturing problems.