US Patent 9533485 Compressor variable vane assembly

A variable vane assembly for a gas turbine engine compressor and method of manufacturing same is described. A plurality of projections the inner and/or outer shroud which protruded into the annular gas path such as to ensure that a radial clearance gap, defined between the projections and a vane airfoil overhang portion, remains substantially constant throughout a substantial portion of the vane pivot arc of the variable vane. The method includes forming one cavities within the shroud, the cavities isolated from the annular gas path and disposed radially beneath at least each of the projections, and providing one or more structural reinforcing elements within the cavities.