Abstract: The present disclosure is directed to a method for scaling an airfoil for placement in a turbomachine. The method disclosed herein includes radially scaling a master airfoil to form a scaled airfoil. The method may also include tuning the scaled airfoil. For example, tuning the scaled airfoil may include axially scaling. The scaled airfoil generally has similar characteristics to the master airfoil.

Abstract: A method of engineering a turbomachine airfoil may include providing a master airfoil configuration having a preset outer and inner radius relative to an axis of rotation thereof. The master airfoil configuration may be radially scaled to a custom-sized turbomachine airfoil having an outer radius different than the preset outer radius of the master airfoil configuration, and/or an inner radius different than the preset inner radius of the master airfoil configuration. Tuning a frequency of the custom-sized turbomachine airfoil by changing a parameter of at least one of a part span shroud and a tip shroud may then be performed. Axial scaling may also be performed. The custom-sized turbomachine airfoil may be employed in the turbomachine without performing wheel box testing, and may exhibit substantially similar operational characteristics as the master airfoil configuration.

Abstract: Fourth stage turbine buckets have airfoil profiles substantially in accordance with Cartesian coordinate values of X, Y and Z set forth Table I wherein X and Y values are in inches and the Z values are non-dimensional values from 0 to 1 convertible to Z distances in inches by multiplying the Z values by the height of the airfoil in inches. The X and Y values are distances which, when connected by smooth continuing arcs, define airfoil profile sections at each distance Z. The profile sections at each distance Z are joined smoothly to one another to form a complete airfoil shape. The X and Y distances may be scalable as a function of the same constant or number to provide a scaled up or scaled down airfoil section for the bucket. The nominal airfoil given by the X, Y and Z distances lies within an envelope of ±0.150 inches in directions normal to the surface of the airfoil.