The gas turbine has a plurality of inlet guide vanes each having a blade having a leading edge, a trailing edge, a span extending along the leading edge, and pivot members at opposite ends of the leading edge, and being pivotally mounted across the radial-to-axial intake via the pivot members, the pivot axis extending axially across a radial portion of the radial-to-axial intake. The plurality of inlet guide vanes include a plurality of first inlet guide vanes, and a plurality of second inlet guide vanes, the second inlet guide vanes having a trailing edge recess differing from the corresponding portion of the first inlet guide vanes. During operation, when the inlet guide vanes are pivoted past a given angle toward the tangential orientation, a radial flow of gas is allowed through the trailing edge recesses to avoid or impede vortex whistle.