Horizontal axis airfoil turbine

Abstract

A Horizontal Axis Airfoil Turbine (HAAT) for harnessing wind power is presented. The horizontal axis airfoil turbine has an airfoil design configured for low cut-in-speed and operational speeds, and for high torque operation. Multiple airfoil blade tips depend inwardly from a structural shroud along the periphery of the shroud. A number of full airfoil blades depend inwardly from the shroud along spokes providing mechanical engagement between the shroud and a central hub. Advantages are derived from a large wind swept area distributed to maximize leverage in order to enable high torque operation.

1 . A horizontal axis airfoil turbine for harnessing wind energy to provide a motive force for use in a power generator, the horizontal axis airfoil turbine comprising:
 a ring configured to provide structural support for an airfoil blade arrangement;   a plurality of airfoil blade tips mechanically connected to, and depending radially from said ring, said blade tips being configured to interact with an airflow incident thereon, said airflow causing a deflection of said blade tips in a direction of rotation of said ring;   a plurality of spokes mechanically connected to, and depending radially inwardly from, said ring, each spoke extending from said ring to a central hub, said spokes providing structural support for said ring and said airfoil blade arrangement;   a plurality of full airfoil blades, each full blade being configured to provide airfoil characteristics to a corresponding spoke for reducing turbulent airflow past said spoke, mechanical engagement between said spokes and said hub providing torsional force transfer to said hub, said hub transforming said torsional force into the motive force for use in the power generator.   
     
     
         2 . The horizontal axis airfoil turbine as claimed in  claim 1 , said ring further comprising an aerodynamically shaped leading edge for reducing resistance to incident wind. 
     
     
         3 . The horizontal axis airfoil turbine as claimed in  claim 1 ,
 said ring further comprising a structural shroud preventing radial airflow spill over distal ends of blades in said airfoil blade arrangement; and   each said airfoil blade tip depending radially inwardly from said ring.   
     
     
         4 . The horizontal axis airfoil turbine as claimed in  claim 3 , said structural shroud having an airfoil cross-section for reducing turbulent airflow around said turbine. 
     
     
         5 . The horizontal axis airfoil turbine as claimed in  claim 4 , said structural shroud having an airfoil tear shaped cross-section. 
     
     
         6 . The horizontal axis airfoil turbine as claimed in  claim 2 , each said airfoil blade tip shaped to operate under one of drag or lift conditions causing said deflection of said blade tip in said direction of rotation of said ring. 
     
     
         7 . The horizontal axis airfoil turbine as claimed in  claim 6 , each said airfoil blade tip having an airfoil tear shaped cross-section for reducing turbulent airflow past said airfoil blade tip. 
     
     
         8 . The horizontal axis airfoil turbine as claimed in  claim 6 , each said airfoil blade tip having an angle of attack between 30° and 50°. 
     
     
         9 . The horizontal axis airfoil turbine as claimed in  claim 8 , said airfoil blade tip angle of attack being substantially 40°. 
     
     
         10 . The horizontal axis airfoil turbine as claimed in  claim 3 , each said airfoil blade tip extending radially inwardly from said ring between 10 to 40 percent of a radius of said ring. 
     
     
         11 . The horizontal axis airfoil turbine as claimed in  claim 10 , each said airfoil blade tip extending radially inwardly from said ring substantially 25 percent of said radius of said ring. 
     
     
         12 . The horizontal axis airfoil turbine as claimed in  claim 2 , each said full airfoil blade shaped to operate under one of drag or lift conditions causing additional deflection of said full airfoil blade in said direction of rotation of said ring. 
     
     
         13 . The horizontal axis airfoil turbine as claimed in  claim 12 , each said full airfoil blade having an airfoil tear shaped cross-section for reducing turbulent airflow past said full airfoil blade. 
     
     
         14 . The horizontal axis airfoil turbine as claimed in  claim 12 , each said full airfoil blade having an angle of attack between 30° and 50°. 
     
     
         15 . The horizontal axis airfoil turbine as claimed in  claim 14 , said full airfoil blade angle of attack being substantially 40°. 
     
     
         16 . The horizontal axis airfoil turbine as claimed in  claim 2 , each said full airfoil blade extending radially inwardly from said ring between 80 to 95 percent of a length of said corresponding spoke. 
     
     
         17 . The horizontal axis airfoil turbine as claimed in  claim 16 , each said full airfoil blade extending radially inwardly from said ring substantially 88 percent of said length of said corresponding spoke. 
     
     
         18 . The horizontal axis airfoil turbine as claimed in  claim 2 , wherein each said airfoil blade tip and each said full airfoil blade have a substantially equal angle of attack. 
     
     
         19 . The horizontal axis airfoil turbine as claimed in  claim 2 , said plurality of full airfoil blades comprising an odd number of said full airfoil blades for reducing harmonic resonant vibration. 
     
     
         20 . The horizontal axis airfoil turbine as claimed in  claim 19 , said odd plurality of full airfoil blades comprising a prime number of said full airfoil blades for minimizing harmonic resonant vibration.