A cooling system integrated into a stator assembly of a gas turbine engine has an on-board injector or cooling nozzle located for cooling of a rotor assembly. The nozzle may be generally annular and may contain a plurality of pivoting airfoils circumferentially spaced from one-another for directing cooling air flow from the nozzle and generally toward a plurality of holes in a cover of the rotor assembly. The pivoting airfoils are adapted to move between a spoiled state where the mass flow of cooling air is reduced, and to an optimal state where the mass flow is increased. The system may further include a plurality of fixed airfoils in the nozzle with adjacent fixed airfoils defining a discharge orifice in the nozzle. Each one of the plurality of pivoting airfoils may be located in a respective discharge orifice.