US Patent 9121284 Modal tuning for vanes

A vane having a cambered airfoil body is frequency-tuned via a number of cavities formed in a surface of the vane. At least some of the cavities are filled with a nonmetallic filler material, and the remainder of the cavities are left unfilled. A cover is affixed to the vane so as to cover at least the unfilled cavities. In an embodiment, the filling and covering of cavities is performed in a manner that excludes the frequency modes of the guide vane from a precluded band, e.g., an engine excitation band.