US Patent 9441488 Film cooling holes for gas turbine airfoils

A new configuration for film cooling holes for gas turbine airfoils, such as rotor blades and stator vanes, provides both improved performance and is easier to manufacture than prior art holes. The new configuration machines a shallow trench across a row of prior art shaped cooling holes. Unlike prior art holes cut through a trench, where shaped holes are difficult to machine through a trench, the shallow trench can be easily machined across a row of shaped cooling holes.