A turbine rotor blade an open cavity and a series of vortex chambers formed along the pressure and suction side walls to form a cooling air path from the leading edge, along the pressure side wall toward the trailing edge, and then from the trailing edge along the suction side wall to be discharged at the leading edge region on the suction side wall as film cooling air. The vortex chambers and feed slots connected adjacent vortex chambers are enclosed with a thin thermal skin to form a thin airfoil wall.