Patent ID: 9284948
Filing Date: 2016-03-15
CPC Classification: F03D,F05B,Y02E

Claim Text:
1. A partial pitch wind turbine blade of at least 35 meters length, the wind turbine blade having an aerodynamic airfoil profile with a leading edge and a trailing edge, the wind turbine blade comprising: an inner blade section; and an outer blade section, the blade sections coupled at a pitch junction such that the outer blade section is pitchable relative to the inner blade section, wherein said inner blade section comprises a truncated airfoil profile provided at said pitch junction, said outer blade section comprises a full airfoil profile portion leading to a truncated airfoil profile portion provided at said pitch junction, wherein the truncated airfoil profiles are provided at the trailing edge of said inner and outer blade sections so that they each provide a truncated trailing edge surface, and wherein said trailing edge is arranged such that the truncated trailing edge surface of said outer blade section projected along a longitudinal axis of the wind turbine blade at least partially intersects the truncated trailing edge surface of the inner blade section when said outer blade section is pitched less than or equal to a pre-defined angle relative to said inner blade section, wherein said pitch is limited to be less than or equal to said pre-defined angle under normal operation in order to prevent the formation of a trailing edge gap at the pitch junction between the trailing edges of the inner and outer blade sections for pitch angles below said pre-defined angle, said pre-defined angle being 8°.