SINCE we do not yet know just what loss in performance occurs as buckets, blades, and vanes vary from the ideal airfoil contour, the authors recommend that these parts be held to the ideal as closely as is commercially practicable.
The British method of attaching the bucket by loosefit, fir-tree root is considered by them to be the best all around method developed to date.
They call attention to the problems of large production welding of turbine wheel buckets, both from the manufacturing and the field replacement viewpoints and point out that remarkable progress has been made with high-temperature alloys, including their handling in production.
They feel that the surface has hardly been scratched as to the future possibilities of engine design, alloys, and improved manufacturing methods for reduced cost and closer tolerances.