A system including an airfoil portion of an unshrouded turbine bucket, which includes a pressure-side surface and suction-side surface each extending from a root surface to a tip surface and joined at a leading edge and a trailing edge, the pressure-side surface having a generally concave shape and the suction-side surface having a generally convex shape; the airfoil portion having an increasing stagger angle in a span-wise direction from the root surface to the tip surface and an increasingly loaded suction-side surface as the suction-side surface approaches the tip surface and the tip surface approaches the leading edge, the airfoil portion having a resultant lean in a direction of the suction-side surface as the leading edge approaches the tip surface, and the pressure-side surface and the suction-side surface each having a locally reduced or reversed curvature in a direction of the pressure-side surface at their intersection with the tip surface.