An airfoil comprising: an outer airfoil wall defining a leading end, a trailing end, a pressure side, a suction side, and a mean line from the leading end to the trailing end that is equidistant from the pressure side and the suction side; and first and second ribs each connecting the pressure side and the suction side, each of the first and second ribs defining a tube portion circumscribing a rib passage, and first and second connector arms (1, 2, 5, 6, 3, 4, 7, 8) solely joining the tube portion to, respectively, the pressure side and the suction side; the first rib, the second rib, and the airfoil wall bounding a continuous cooling channel there between, the continuous cooling channel having a pressure side portion to the pressure side of the mean line and a suction side portion to the suction side of the mean line, the pressure side portion and the suction side portion each having a cross-sectioned shape selected from an L-shape, a T-shape, and an l-shape, characterized in that the pressure side portion and the suction side portion each having a cross-sectioned shape selected from the L-shape, the T-shape, and the 1-shape in one of the following configurations: i) the pressure side portion is the T-shape and the suction side portion is the L-shape; or ii) the pressure side portion is the L-shape and the suction side portion is the T-shape; or iii) the pressure side portion is the 1-shape and the suction side portion is the L-shape; or iv) the pressure side portion is the L-shape and the suction side portion is the l-shape; or v) the pressure side portion is the 1-shape and the suction side portion is the T-shape; or vi) the pressure side portion is the T-shape and the suction side portion is the l-shape. an outer airfoil wall defining a leading end, a trailing end, a pressure side, a suction side, and a mean line from the leading end to the trailing end that is equidistant from the pressure side and the suction side; and first and second ribs each connecting the pressure side and the suction side, each of the first and second ribs defining a tube portion circumscribing a rib passage, and first and second connector arms (1, 2, 5, 6, 3, 4, 7, 8) solely joining the tube portion to, respectively, the pressure side and the suction side; a tube portion circumscribing a rib passage, and first and second connector arms (1, 2, 5, 6, 3, 4, 7, 8) solely joining the tube portion to, respectively, the pressure side and the suction side; the first rib, the second rib, and the airfoil wall bounding a continuous cooling channel there between, the continuous cooling channel having a pressure side portion to the pressure side of the mean line and a suction side portion to the suction side of the mean line, the pressure side portion and the suction side portion each having a cross-sectioned shape selected from an L-shape, a T-shape, and an l-shape, characterized in that the pressure side portion and the suction side portion each having a cross-sectioned shape selected from the L-shape, the T-shape, and the 1-shape in one of the following configurations: i) the pressure side portion is the T-shape and the suction side portion is the L-shape; or ii) the pressure side portion is the L-shape and the suction side portion is the T-shape; or iii) the pressure side portion is the 1-shape and the suction side portion is the L-shape; or iv) the pressure side portion is the L-shape and the suction side portion is the l-shape; or v) the pressure side portion is the 1-shape and the suction side portion is the T-shape; or vi) the pressure side portion is the T-shape and the suction side portion is the l-shape. i) the pressure side portion is the T-shape and the suction side portion is the L-shape; or ii) the pressure side portion is the L-shape and the suction side portion is the T-shape; or iii) the pressure side portion is the 1-shape and the suction side portion is the L-shape; or iv) the pressure side portion is the L-shape and the suction side portion is the l-shape; or v) the pressure side portion is the 1-shape and the suction side portion is the T-shape; or vi) the pressure side portion is the T-shape and the suction side portion is the l-shape.