Patent ID: 7926290
Filing Date: 2011-04-19
Classification: F02K

Abstract:
1. A method of operating a gas turbine engine, comprising: (a) burning a fuel in a turbomachinery core to produce a first flow of pressurized combustion gases; (b) extracting energy from the first flow of pressurized combustion gases and using the energy to generate a first flow of pressurized air with a rotating fan; (c) rotating the fan at a constant speed at a maximum RPM in all flight conditions; (d) selectively varying a flow area through the fan to vary the first flow of pressurized air while the fan rotates at the constant speed; and (e) using the fan to mechanically drive a FLADE stage comprising a supplementary fan disposed in a fan outer duct, so as to generate a pressurized bleed air flow having a magnitude independent of the first flow of pressurized air, wherein discharge of the FLADE stage remains at a constant flow and pressure ratio level.