Large airfoil structure and method for its manufacture

A large wind-driven power plant having a rotor blade with an airfoil structure having an upper airfoil surface and a lower airfoil surface comprising:

• three modular sections consisting essentially of a leading section defining a leading edge of said airfoil, a trailing section defining a trailing edge of said airfoil, and a spar section intermediate said leading and trailing sections;
• said modular sections being separately formed and subsequently assembled together to form said airfoil structure;
• said spar section being formed to consist essentially of an upper segment defining a part of said upper airfoil surface and a lower segment defining a part of said lower airfoil surface, said parts of said upper and lower airfoil surfaces extending along the section of said airfoil structure defined by said spar section;
• each of said upper and lower segments of said spar sections being formed to comprise a plurality of laminate shells with at least one foam bar unit supporting said laminated shells;
• said upper and lower segments being joined together along planar surfaces thereof which are parallel to an imaginary plane extending between said leading and said trailing edges of said airfoil structure;
• said spar section being divided into a lower and an upper segment each having one laminate shell and half of a foam bar unit and each being glued together at cut end faces of said foam bar unit half which face one another, said foam bar halves being glued and cut approximately with the shells with said foam bars being reinforced at longitudinal sides by the inclusion of bar laminates.

A large wind-driven power plant having a rotor blade with an airfoil structure having an upper airfoil surface and a lower airfoil surface comprising:

• three modular sections consisting essentially of a leading section defining a leading edge of said airfoil, a trailing section defining a trailing edge of said airfoil, and a spar section intermediate said leading and trailing sections;
• said modular sections being separately formed and subsequently assembled together to form said airfoil structure;
• said spar section being formed to consist essentially of an upper segment defining a part of said upper airfoil surface and a lower segment defining a part of said lower airfoil surface, said parts of said upper and lower airfoil surfaces extending along the section of said airfoil structure defined by said spar section;
• each of said upper and lower segments of said spar sections being formed to comprise a plurality of laminate shells with at least one foam bar unit supporting said laminated shells;
• said upper and lower segments being joined together along planar surfaces thereof which are parallel to an imaginary plane extending between said leading and said trailing edges of said airfoil structure;
• said trailing section being comprised of a lower half and an upper half with said trailing section halves being formed as light laminar structures each formed with an elastic extension at longitudinal sides thereof adapted to be connected with said spar section with a glued-on foam strip forming a thickened trailing edge end of said trailing section.

A large wind-driven power plant having a rotor blade with an airfoil structure having an upper airfoil surface and a lower airfoil surface comprising:

• three modular sections consisting essentially of a leading section defining a leading edge of said airfoil, a trailing section defining a trailing edge of said airfoil, and a spar section intermediate said leading and trailing sections;
• said modular sections being separately formed and subsequently assembled together to form said airfoil structure;
• said spar section being formed to consist essentially of an upper segment defining a part of said upper airfoil surface and a lower segment defining a part of said lower airfoil surface, said parts of said upper and lower airfoil surfaces extending along the section of said airfoil structure defined by said spar section;
• each of said upper and lower segments of said spar sections being formed to comprise a plurality of laminate shells with at least one foam bar unit supporting said laminated shells;
• said upper and lower segments being joined together along planar surfaces thereof which are parallel to an imaginary plane extending between said leading and said trailing edges of said airfoil structure;
• said segments of said spar section being thickened in the proximity of disconnecting points thereof at their shells at least in a flange area with an additional layer and having at their disconnecting points laterally at said foam bar units transverse force connection layers.