Patent ID: 7600976
Filing Date: 2009-10-13
Classification: B64C,Y10S

Abstract:
1. A main rotor blade assembly for a rotary wing aircraft comprising: a main rotor blade root region containing a root region twist within said main rotor blade root region transverse to a feathering axis, said root region twist having a positive twist gradient; a main rotor blade inboard region outboard of said main rotor blade root region, said main rotor blade inboard region containing an inboard chord within said main rotor blade inboard region transverse to said feathering axis; a main rotor blade main region outboard of said main rotor blade inboard region, said main rotor blade main region containing a main region twist within said main rotor blade main region transverse to said feathering axis, said main region twist having a negative twist gradient; a main rotor blade tip region outboard of said main region, said tip, region containing a tip region twist within said main rotor blade tip region transverse to said feathering axis, said tip region twist having a negative twist gradient more negative than said main region twist gradient; and a blade chord defined between a leading edge and a trailing edge, said trailing edge defined along a root trailing edge of said main rotor blade root region, an inboard region trailing edge of said main rotor blade inboard region, a main region trailing edge of said main rotor blade main region and a tip region trailing edge of said main rotor blade tip region, said inboard region trailing edge defining a point A and a point B, said point B outboard of said point A, said main region trailing edge defining a point C and a point D, said point D outboard of said point C, said blade chord increasing between said point A and said point B and decreasing between said point C and said point D, said main rotor blade maximum chord located between said point B and said point C from said root attachment section to said main region section and decreasing from said main region section to said tip region section.