A rotor blade, comprising: a root; a hollow airfoil having a cavity defined by a suction side wall, a pressure side wall, a leading edge, a trailing edge, a base, and a tip. an internal passage configuration disposed within the cavity, which configuration includes a first radial passage, a second radial passage, a rib disposed between and separating the first radial passage and second radial passage, a plurality of crossover apertures disposed within the rib, and a plurality of trip strips disposed within the first radial passage, wherein the plurality of trip strips are disposed within the first radial passage at an angle α that is skewed relative to a cooling airflow direction within the first radial passage, and positioned such that each of the plurality of trip strips converges toward the rib, and a rib end of at least a portion of the plurality of trip strips is located between a pair of adjacent crossover apertures; and a conduit disposed within the root that is operable to permit airflow through the root and into the first passage; characterised in that: the plurality of trip strips are attached to an interior surface of one of the pressure side wall and the suction side wall; the crossover apertures are located within the rib closer to the pressure side wall than the suction side wall, or the crossover apertures are located within the rib closer to the suction side wall than the pressure side wall, and in that the plurality of trip strips are attached to the interior of the wall (36, 38) towards which the crossover apertures are shifted. a root; a hollow airfoil having a cavity defined by a suction side wall, a pressure side wall, a leading edge, a trailing edge, a base, and a tip. an internal passage configuration disposed within the cavity, which configuration includes a first radial passage, a second radial passage, a rib disposed between and separating the first radial passage and second radial passage, a plurality of crossover apertures disposed within the rib, and a plurality of trip strips disposed within the first radial passage, wherein the plurality of trip strips are disposed within the first radial passage at an angle α that is skewed relative to a cooling airflow direction within the first radial passage, and positioned such that each of the plurality of trip strips converges toward the rib, and a rib end of at least a portion of the plurality of trip strips is located between a pair of adjacent crossover apertures; and a conduit disposed within the root that is operable to permit airflow through the root and into the first passage; characterised in that: the plurality of trip strips are attached to an interior surface of one of the pressure side wall and the suction side wall; the crossover apertures are located within the rib closer to the pressure side wall than the suction side wall, or the crossover apertures are located within the rib closer to the suction side wall than the pressure side wall, and in that the plurality of trip strips are attached to the interior of the wall (36, 38) towards which the crossover apertures are shifted. the plurality of trip strips are attached to an interior surface of one of the pressure side wall and the suction side wall; the crossover apertures are located within the rib closer to the pressure side wall than the suction side wall, or the crossover apertures are located within the rib closer to the suction side wall than the pressure side wall, and in that the plurality of trip strips are attached to the interior of the wall (36, 38) towards which the crossover apertures are shifted.