An airfoil for a rotor blade in a gas turbine engine includes a first side wall and a second side wall joined to the first side wall at a leading edge and a trailing edge. The airfoil further includes a tip cap extending between the first and second side walls such that the tip cap and at least portions of the first and second side walls form a blade tip and an internal cooling system. The internal cooling system includes a leading edge cooling circuit, a central cooling circuit, and a trailing edge cooling circuit. Each of the internal passages within the leading edge cooling circuit, the central cooling circuit, and the trailing edge cooling circuit is bounded in the radial outward direction with a surface that has at least one escape hole or that is positively angled in the radial outward direction relative to a chordwise axis.