US Patent 10227931 Variable inlet guide vane scheduling

There is disclosed an aero gas turbine engine comprising a compressor and an array of variable inlet guide vanes for the compressor. The angle of the variable inlet guide vanes is controlled by scheduling, the scheduling comprising a first component invoked for engine ground start and a second component invoked for engine in-flight windmill start at least under particular flight conditions. The angle of the variable inlet guide vanes required by at least a portion of the second component is greater than the angle of the variable inlet guide vanes required by at least a portion of the first component.