Airfoil with large fillet and micro-circuit cooling

A gas turbine engine blade (11) has a relatively large fillet (18) to improve the characteristics of the air flow thereover. The fillet (18) has a thin wall which partially defines a fillet cavity (24) therebehind, and cooling air is provided to the fillet cavity (24) and is then routed to the outer surface by way film cooling holes (41). Various design features are provided to enhance the effectiveness of the cooling air being provided to both the fillet cavity (24) and other cavities within the blade.