US Patent 9004850 Twisted variable inlet guide vane

A compressor for a gas turbine engine with variable inlet guide vanes each defining an airfoil portion twisted such that at each location of the airfoil portion along the pivot axis, an angle is defined between a respective chord extending between the leading and trailing edges and a same reference plane containing the pivot axis and extending radially with respect to the compressor. The angle, which is measured along a direction of rotation of the rotor, varies from a minimum value near the hub side wall to a maximum value near the shroud side wall. A method of reducing vortex whistle in a radial inlet of a compressor is also provided.