Patent ID: 8083484

Claim:
A turbine rotor blade for a gas turbine engine including an airfoil and dovetail for mounting the airfoil along a radial axis to a rotor disk inboard of a turbine shroud, the airfoil comprising: a pressure sidewall and a suction sidewall that join together at a leading edge and a trailing edge, the pressure sidewall and suction sidewall extending from a root to a tip plate; a pressure tip wall that extends radially outwardly from the tip plate, traversing from the leading edge to the trailing edge such that the pressure tip wall resides approximately adjacent to the termination of the pressure sidewall; a suction tip wall that extends radially outwardly from the tip plate, traversing from the leading edge to the trailing edge such that the suction tip wall resides approximately adjacent to the termination of the suction sidewall; and or more tip ribs that extend substantially between the pressure tip wall and the suction tip wall; wherein: a tip mid-chord line comprises a reference line extending from the leading edge to the trailing edge that connects the approximate midpoints between the pressure tip wall and the suction tip wall; each of the tip ribs are configured such that a longitudinal axis extending through each tip rib forms an angle with the tip mid-chord line; and each of the angles falls within the a range of approximately 80°-100°.