Patent ID: 6071077
Filing Date: 2000-06-06
Classification: F01D,F04D,Y02T,Y10S

Abstract:
A fan stage of a ducted fan gas turbine engine, comprisinga fan casing having an inner duct wall which in a fan rotor region is convergent in the downstream direction; anda fan rotor including a multiplicity of swept fan blades spaced apart around a hub mounted concentrically with respect to the fan duct, each of said swept fan blades having a tip profile which in revolution is convergent so as to substantially correspond to the convergent duct wall, a leading edge of variable sweep angle which varies with increasing blade height or distance from the axis of rotation, said sweep angle having a forward sweep angle in a first height region between the root and a first intermediate radius, a rearward sweep angle in an intermediate height region between the first intermediate radius and a second intermediate radius, a forward sweep angle in a third height region between the second intermediate radius and the tip of the blade, a stagger angle which increases progressively with blade height.