Composite wind turbine rotor blade and method for making same

A wind turbine rotor blade having an outer skin of fiberglass plies impregnated with polymer resin, said rotor blade comprising:

• a spar extending longitudinally within said rotor blade, said spar having a substantially rectangular cross-section, said spar having a first wall affixed to a first inner surface of said skin and a second wall affixed to a second inner surface of said skin, a third wall and a fourth wall, said third and fourth walls extending substantially perpendicularly to said inner surfaces of said skin from said first wall to said second wall;
• a first channel extending longitudinally within said rotor blade, said first channel having a first wall extending parallel to said third wall of said spar and affixed thereto, a second wall extending parallel to said first inner surface of said skin and affixed thereto, and a third wall extending parallel to said second inner surface of said skin and affixed thereto, said second wall and said third wall extending away from said spar;
• a second channel extending longitudinally within said rotor blade, said first channel having a first wall extending parallel to said fourth wall of said spar and affixed thereto, a second wall extending parallel to said first inner surface of said skin and affixed thereto, and a third wall extending parallel to said second inner surface of said skin and affixed thereto, said second wall and said third wall extending away from said spar;
• a leading edge assembly formed of said plies of fiberglass, said leading edge assembly having a closed leading edge and rear edges defining an open rear, several of said layers extending short of said rear edges so that a thickness of said leading edge assembly is reduced in first attachment regions adjacent said rear edges;
• a trailing edge assembly formed of said plies of fiberglass, said trailing edge assembly having a closed trailing edge and front edges defining an open front, several of said layers extending short of said front edges so that a thickness of said trailing edge assembly is reduced in second attachment regions adjacent said front edges;
• said first attachment regions and said second attachment regions being of substantially complementary shape, said first attachment regions being of a thickness sufficient to receive the reduced thickness of said second attachment regions;
• said rotor blade also having:
• a thickness-to-chord ratio of substantially sixteen percent at full radius, said thickness increasing to substantially nineteen percent at one half full radius and substantially twenty nine percent at three-tenths full radius;
• and
• a twist equal to zero from full radius to fifty percent full radius, said twist varying to a value no greater than eight degrees at a theoretical hub of the rotor blade.

A wind turbine rotor blade comprising:

• a first portion formed of fiberglass reinforced polymer resin, said first portion having a first part shaped as an airfoil and an end shaped as a cylinder;
• a second portion formed of a metal, said second portion being adapted for coupling said blade to a rotor hub, said second portion having a cylindrical sleeve which engages said end so that at least a first circumferential surface of said sleeve contacts a second circumferential surface of said end;
• a polymer primer disposed on said first circumferential surface;
• an adhesive disposed between said primer on said first circumferential surface and said second circumferential surface;
• and
• at least one mechanical fastener for fastening said end to said sleeve.

A wind turbine rotor blade comprising:

• a first portion formed of fiberglass reinforced polymer resin, said first portion having a first part shaped as an airfoil and an end shaped as a cylinder;
• a second portion formed of a metal, said second portion being adapted for coupling said blade to a rotor hub, said second portion having a cylindrical sleeve which engages said end so that at least a first circumferential surface of said end;
• an adhesive disposed between said first circumferential surface and said second circumferential surface;
• and
• at least one mechanical fastener for fastening said end to said sleeve;
• wherein said first portion includes an outer skin and a spar extending longitudinally within said skin, said skin and said spar having concentric circular cross sections at said end, an inner surface of said skin being in contact with an outer surface of said sleeve, and an outer surface of said spar being in contact with an inner surface of said sleeve;
• and said adhesive being disposed between said inner surface of said skin and said outer surface of said sleeve, and between said outer surface of said spar and said inner surface of said sleeve.