An airfoil comprising: a leading edge and a trailing edge; a suction surface and a pressure surface, the suction surface and the pressure surface both extending axially between the leading edge and the trailing edge, as well as radially from a root section to a tip section of the airfoil; a cooling passageway located between the suction surface and the pressure surface; a plurality of axially elongated oblong pedestals arranged in a first radial column, wherein each of the plurality of oblong pedestals includes a curved axially upstream end and a blunt axially downstream end; a plurality of downstream pedestals arranged into a second radial column; and a plurality of upstream cylindrical pedestals arranged in a third radial column, a fourth radial column and a fifth radial column, wherein: the curved axially upstream end and the angular axially downstream end are connected by two substantially parallel sides (152,154), or each of the plurality of oblong pedestals tapers from the curved axially upstream end and the angular axially downstream end; characterised in that the plurality of oblong pedestals connect the suction surface to the pressure surface at the trailing edge of the airfoil, and the downstream end terminates at the trailing edge of the airfoil; and both the plurality of oblong pedestals and the plurality of downstream pedestals are more densely packed than the plurality of cylindrical pedestals are packed in the third column, the fourth column and the fifth column. a leading edge and a trailing edge; a suction surface and a pressure surface, the suction surface and the pressure surface both extending axially between the leading edge and the trailing edge, as well as radially from a root section to a tip section of the airfoil; a cooling passageway located between the suction surface and the pressure surface; a plurality of axially elongated oblong pedestals arranged in a first radial column, wherein each of the plurality of oblong pedestals includes a curved axially upstream end and a blunt axially downstream end; a plurality of downstream pedestals arranged into a second radial column; and a plurality of upstream cylindrical pedestals arranged in a third radial column, a fourth radial column and a fifth radial column, wherein: the curved axially upstream end and the angular axially downstream end are connected by two substantially parallel sides (152,154), or each of the plurality of oblong pedestals tapers from the curved axially upstream end and the angular axially downstream end; characterised in that the plurality of oblong pedestals connect the suction surface to the pressure surface at the trailing edge of the airfoil, and the downstream end terminates at the trailing edge of the airfoil; and both the plurality of oblong pedestals and the plurality of downstream pedestals are more densely packed than the plurality of cylindrical pedestals are packed in the third column, the fourth column and the fifth column. the curved axially upstream end and the angular axially downstream end are connected by two substantially parallel sides (152,154), or each of the plurality of oblong pedestals tapers from the curved axially upstream end and the angular axially downstream end; characterised in that the plurality of oblong pedestals connect the suction surface to the pressure surface at the trailing edge of the airfoil, and the downstream end terminates at the trailing edge of the airfoil; and both the plurality of oblong pedestals and the plurality of downstream pedestals are more densely packed than the plurality of cylindrical pedestals are packed in the third column, the fourth column and the fifth column.