Abstract:
A renewable energy system for directly charging electric and hybrid vehicles is shown for areas with modest wind resources and/or solar resources. The invention consists of a composite stanchion for mounting on a base in a parking lot that is both capable of supporting a medium sized wind turbine (or solar array) and serving as a battery storage and charging control station. Significant improvements in blade pitch adjustment and cost reduction for wind turbine blades allow the system to operate at an acceptable cost in areas with modest winds and avoid the need for remotely supplied renewable electricity in areas of high population density. In turn, this will allow for increased electrical grid stability through increased use of distributed generation.

Description:
BACKGROUND 
     1. Field of the Invention 
     This invention relates to distributed energy systems for populated areas; specifically a system for hybrid or electric vehicle charging based on an improved vertical axis wind turbine and support structure. 
     2. Prior Art 
     Recent emphasis on energy independence, economics and the effects of climate change has led to a re-thinking of the rate of conversion to alternative fuel supplied vehicles. Nearly all major auto makers presently have or are planning hybrid, plug-in hybrid and all electric vehicles in addition to expanding lines of natural gas fueled and alcohol fueled cars into the US from established markets elsewhere. 
     Many recent patents on vehicle charging have centered on transmission of power within vehicles and electrical charging dynamics and controls: (Matsubara U.S. Pat. No. 7,426,973, Barske U.S. Pat. No. 7,377,344, Gouda U.S. Pat. No. 7,381,146, Honda U.S. Pat. No. 7,412,309, Ishishita U.S. Pat. No. 7,439,710, Egami U.S. Pat. No. 7,443,117, Sobue U.S. Pat. No. 7,471,064, Suzuki U.S. Pat. No. 7,482,779, Nakamura U.S. Pat. No. 7,486,034). 
     Where inventors have focused on directly charging batteries with renewable energy, such as Rosen U.S. Pat. No. 7,459,880 and Chang U.S. Pat. No. 7,476,987, again the electrical aspects of the design dominate the specifications. 
     Better Place, a firm with a number of international and domestic electric car charging/parking lot installations, utilizes alternating current supply posts put in as branch circuits to accomplish a goal of supplying purchased ‘green electricity’ generated remotely from the site to the vehicles. Sources of economical green electricity in proximity to points of use are extremely rare. 
     Very large, three blade horizontal axis turbines (HAWT) are the central hope for use in supplying pollution free electrical demand to meet the perceived needs of the national distribution grid. But they require a massive thickness of expensive composite materials at the blade root and roughly 600 man-hours of labor for each blade. 
     They are not economical in areas with moderate winds because of the cost elements cited above, the cost of the heavy nacelle assembly and its structural support, costs of the grid interface and the mechanism for directing the turbine into the wind. As manufacturers have steadily increased the size of the turbines and built more of them, cost per kilowatt hour has gone up . . . not down. 
     Rather than addressing the obvious limitations of HAWT, many are recommending trans-continental transmission from high wind areas to high population areas to meet growing energy needs. One drawback of this approach was illustrated within the report on the August 2003 power outage: Electricity purchased from utilities outside of service areas grew from 18% of total use in 1989 to about 40% of total use in 2002. Moving enough electricity across the country to both meet existing needs and electric vehicle needs from wind sites in the Great Plains area will require very expensive high voltage transmission lines and corridors. Writing off functioning coal fired power plants before they are obsolete is beyond the economic capabilities of the country. 
     Every kilowatt hour (kWh) of energy delivered to an end user, requires of 3.23 kilowatt hours of coal energy at a power plant. As stated by the Department of Energy, ‘energy security’ is best provided by distributed energy sources. Therefore, the use of wind energy in distributed power generation in many applications including replacement of fossil fuels has emerged as an important new option. Hartman (U.S. Pat. No. 7,329,099, 2008) shows a vertical axis design for generating heat to displace natural gas in HVAC systems and to cut coal-based electrical power emissions in existing power plants with nearby off-shore wind. 
     A number of earlier inventions for vertical axis turbines obtained good efficiency and self-starting capability through pivoting blades to optimize lift throughout the rotational cycle. This permitted lower costs through reducing materials usage relative to horizontal turbines. The mechanical complexity of the pitch control, however, may have been a factor contributing to the displacement of vertical turbines by horizontal turbines over the past two decades. 
     Sicard (U.S. Pat. No. 4,048,947, 1979) used a combination of counterweights and aerodynamic forces to orient blades to minimize drag around the circuit of rotation of a vertical turbine. Blades illustrated by Sicard are simple pipes to ease the mechanical requirements of the pivoting motion with trailing edges bonded to the pipe sections to form an airfoil. 
     Drees (U.S. Pat. No. 4,180,367, 1979) achieved self-starting characteristics in the ‘Cycloturbine’ by imposing an orientation at the retreating blade position perpendicular to the ambient wind direction at low starting speeds. He had an orientation parallel to prevailing wind at operational wind speeds. Mechanical actuation of the system was by cam and pushrods to each blade . . . not a significant improvement on the internal combustion engine in terms of simplicity. 
     Liljegren (U.S. Pat. No. 4,430,044, 1984) utilized similar cams and pushrods to control the pitch of the blades of a vertical axis turbine during the rotational cycle. This system differs from Drees in orienting both the blade positions approaching and receding from the prevailing wind roughly parallel to the tangent of the rotational circle to limit drag; Aiming for lift-based power throughout the rotational cycle and a wider range of operational speeds of the machine. 
     Given that improvements in vertical turbine performance can be achieved with small amounts of pitch variation, (Thesis, Pawsey, 2002), it is likely that complex mechanical drive mechanisms for pitch control used in these earlier inventions could be supplanted by simpler alternatives. 
     Vertical axis designs using drag based impellers have emerged to supply small amounts of site generated electricity in buildings. Naskali (U.S. Pat. No. 7,344,353, 2008) and Rahai (U.S. Pat. No. 7,393,177, 2008) are two examples of improvements on the earlier Savonius style. While effective, the complex shapes and large chords of these reactive surfaces limit the scale of the systems and increase unit electricity costs due to the complex forms. 
     While the approach to the orientation of the approaching and receding blades seen in Liljegren is appropriate for vertical turbines with two or three blades and low solidity, it is based on the assumption that the prevailing wind is the same as the wind direction moving around and through a vertical turbine. Studies of airflow around cylinders and consideration of the Magnus effect show that this assumption may be inadequate to capture the flow field of a vertical turbine, particularly at high solidity and/or multiple blades. 
     Roberts (U.S. Pat. No. 7,329,965, 2008) recognizes the importance of considering flow through the turbine assembly in his design for an “Aerodynamic hybrid” vertical turbine; but is also limited by the size and fabrication complexity factors discussed above for drag type turbines. 
     FloWind Inc. in conjunction with Sandia Labs conducted experiments in the late 1980s/early 1990s to reduce cost and improve performance in Darrieus style vertical turbines used in early utility installations by replacing extruded aluminum blades with composite pultrusions, (SAND 96-2205, 1996). While reasons are unclear; the newer, more elongated turbine rotor design and Sandia blade aerodynamics did not result in significantly higher efficiency or any reduced cost. 
     Wallaces pultrusion (U.S. Pat. No. 5,499,904 to FloWind) was large and complex, with a chord of 27 inches and four cavities in the profile separated by web portions. Production of the system using the pultrusion process was likely difficult. The field bending of the 158 ft long turbine blades into a troposkein curve was also a limitation on practicality. 
     Hartman (U.S. Pat. No. 7,329,099, 2008) produced a dome structure based on straight blades used as dome struts with an initial approach to variable pitch throughout the rotation. The two cavity pultrusion was simpler than that of Wallace, but there remain some issues with the design of the blade—hub attachment system and the need for simple, adaptable blade pitch control. 
     The new emphasis on distributed power opens up a number of new wind applications; such as local recharging of hybrid or all-electric vehicles and mid-scale wind power generation at industrial/commercial buildings, if significant cost reduction over HAWT electrical generation and drag-based, complex shape, vertical axis units could be demonstrated. 
     OBJECTS AND ADVANTAGES OF THE INVENTION 
     Accordingly, one object of the invention is to produce low cost, efficiently produced blades for use in vertical axis turbines. A second object of the invention is to replace complex systems of mechanical pivots, stops/springs and cams with simpler, more robust systems to allow pitch control and pivoting of turbine blades through the rotational cycle of a turbine. Practical systems suited to addressing emerging needs for locally produced renewable energy in populated areas with Class 2 and Class 3 (moderate) winds are another object of the invention. 
     SUMMARY OF THE INVENTION 
     To address these objectives, a first aspect of the invention is to provide a single cavity, pultruded airfoil shape that can be combined with a simple I beam pultruded profile to produce a very low cost composite blade for wind turbines. 
     This two part assembly strategy allows for blade angles relative to the perimeter of turbine rotation that can be easily adjusted to allow for varying amounts of heel-in or heel-out angle that form the center point of a blade pivoting system. 
     A second aspect of the invention is the use of a composite section as a replacement for the complex pivot shaft and stops/springs in prior art vertical blade pivoting assemblies. The composite functions as a simple torsion spring during the rotational cycle and an easy tie point to hub junctions for the blades in a turbine rotor assembly. 
     A third aspect of the invention is a stanchion support/energy vending station that can be placed in service in an existing parking lot to serve as an infrastructure element in the move toward a practical, modular infrastructure for rechargeable electric cars and plug-in hybrid vehicles. Instances supporting both wind turbines and solar collector arrays are disclosed in the specifications. 
     The unique stanchion allows ease of installation to concrete bases found in many parking lots for lighting. It also serves as an electrically insulating housing for batteries and lightweight structural member. Dual use for night lighting of lots without additional grid demand and an emergency power supply for nearby buildings can also be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a birds eye view of a parking lot area equipped with both wind and solar energy vending systems for charging vehicles. 
         FIG. 2  is an isometric assembly drawing of the energy storage/structural stanchion and generator housing for the wind turbine shown in  FIG. 1 . 
         FIG. 3  is a cross section of the stanchion showing additional electrical and structural components of the renewable energy vehicle fueling system. 
         FIGS. 4   a  and  4   b  are cross sections through two different types of composites used in the invention. 
         FIG. 5  is a process and instrument drawing of the control and electrical supply components and their interconnections for a wind turbine vehicle charging station. 
         FIG. 6  is cross section through the composite blade structure of the invention. 
         FIG. 7  is a schematic illustration of the pivoting blades throughout a rotational cycle. 
         FIG. 8  is an isometric assembly drawing of a turbine blade hub. 
         FIG. 9  is a detail assembly drawing of turbine blade attachment to a hub. 
         FIG. 10  is a view of an alternate embodiment of the blade structure invention. 
         FIG. 11  is a cross section of a pivoting blade assembly using a composite sheet. 
         FIG. 12  is a detail isometric assembly drawing of the turbine blade hubs shown in  FIG. 10 . 
         FIG. 13  is a cross section of an alternate material use using a wood insert. 
         FIG. 14  is a cross section of an alternate material use using a foam filled airfoil. 
         FIG. 15  is a part drawing of an alternate shape for the composite blade beam. 
         FIG. 16  is an isometric drawing of a composite blade twisted along its longitudinal axis. 
         FIG. 17  is a side view elevation of the solar array structure 
         FIG. 18  is a cut away drawing of a typical photovoltaic/structural panel 
     
    
    
     DETAILED DESCRIPTION 
     Support Stanchion with Integrated Vehicle Charging System 
       FIGS. 1 through 5  disclose a preferred embodiment of the invention: A composite stanchion  50  and associated electric equipment with the capability to both support a vertical axis wind turbine rotor  21  and to store/supply energy for hybrid or electric vehicles  79 . Stanchion  50  can also support an elevated solar array  30  having an adjustable pitch mechanism for optimum solar collection capability. 
     Through public facilities to provide for direct supply of vehicle energy from renewable sources; new demand on an already stressed grid structure and carbon emissions from vehicle sources can both be minimized. Additionally, the renewable energy supplied from the invention can be easily utilized for emergency power supply to a nearby building or local grid area for greater energy assurance. 
       FIG. 1  is an overview of a parking lot  68 , with vehicles  79   a, b  and  c  are in the process of being charged through cables  71   a, b  and  c  with power supplied by support stanchions  50   a  and  50   c . Wind turbine assembly  20  consists of a wind turbine rotor  21 , a housing  40 , a stanchion  50   a  and a base assembly  60 . Although a vertical turbine design based on U.S. Pat. No. 7,329,099 is illustrated in the figure, another wind turbine design could be used in conjunction with the support stanchion and energy supply system. 
     Support stanchion  50   b  carrying lighting fixture  66  is shown with buried conduit  65  for utilization of energy generated by turbine assembly  20  for electrical energy storage in stanchion  50   b  or night lighting of the parking lot. Fixture  66  is preferably a DC supply, high intensity discharge luminaire capable of operation off stanchion supplied voltage at high efficiency. 
     An extension  67  of conduit  65  can be utilized to connect to and utilize energy from a grid connected panel  73  associated with the lot for the purpose of supplying backup power to any of the stanchions,  50   a  through  d  for charging vehicles or lighting in time of low renewable energy supply. Alternatively, extension  67  can be configured to deliver excess electrical supply to a building or service supply grid as needed through panel  73 . 
     Solar array  30  consists of a series of photovoltaic solar structural panels  31  supported by a perimeter frame  32  and intermediate beams  33  tied to stanchions  50   c  and  50   d . Integral purlins  36  within panels  31  provide tie members between the beams, which are in turn are connected to stanchions  50   c  and  50   d  with a hinged connector  35  to control the pitch of the array. Inter-panel connectors  34  add to the diaphragm strength/racking resistance of the overall solar platform deck  37  in areas with seismic structural concerns. 
     Although a ‘portal’ assembly of stanchions and deck is shown in the illustration, individual support of deck sections with individual stanchions could also be achieved with the system. It is not intended to limit the scope of the invention to either a pivoting or fixed pitch assembly of the solar collector deck. 
     A more detailed description of improved turbine blades  23 , hub assembly  25  and information on a simple blade pitch control system  106  is provided in the specification associated with  FIGS. 6 through 16 . The connection of mast  22  through housing  40  to generator  45  is detailed in  FIG. 2 . Non-blade dome struts  24  are also shown in  FIGS. 1 and 8 . 
       FIG. 2  is an assembly drawing of wind turbine assembly  20  divided into sections according to sketches of a housing  40 , a stanchion  50  and a base assembly  60 . Mast  22  passes through a housing frame  41  by means of a bearing/seal assembly  42  and ends at a rotary coupling  46  to the shaft of a direct current generator  45 . Power output of generator  45  is conducted into power conditioning panel  44  through wiring  48 . Conditioned power is then supplied to programmable controller  57  through flexible conduit  47  which is later attached at conduit fitting  47   a  to stanchion  50 . Another type of generator, such as a synchronous one, could be used within the scope of the invention. 
     Anchor blade  43  is structurally bonded to housing  41  at the bottom and is later inserted into a slot  53  between double web sections  52   b  of pultruded composite profile  51 . Web sections  52   b  are connected to the center points of flanges  52   a  to make up the structural support of stanchion  50 . 
     The stanchion carries deep discharge batteries  55   a ,  55   b  . . . etc in the cavity formed between flanges  55   a  and web face  54 . The batteries are supported from below by brackets  59  which are bonded to the flanges. Two stacks of batteries can be employed in the stanchion, one on either side of web sections  52   b . Wire connections  56   a  are affixed to battery terminals by terminal connectors  56   b  at one end and selectively connected to either controller  57  to optimize charging or controller  58  to transfer energy to vehicles or other energy use components. 
     Programmable controller  58  at the bottom of the battery stack connects to user interface  72  for vehicle charging, or to lighting and other storage locations such as stanchion  50   b  or panel  73  by means of modular connector strips  58   a.    
     During field assembly, base assembly  60  is attached to concrete base  64  by means of threaded studs  63  and nuts  62 . A base plate  61  has post  61   a  and alignment blocks  61   b  bonded to it to form the base assembly. Alignment blocks  61   b  are offset from post  61   a  to leave gaps  61   c  which are slightly wider than web sections  52   b  (which are ultimately positioned in the gaps). 
     In the installation process, profile  51  is mounted on post  61   a  by means of slot  53  and secured in place, Housing  40  is later installed by means of anchor blade  43  as described above. Holes in parts  61   a  and  43 , ( 61   d  and  43   a  respectively), correspond to additional bolting during assembly that cannot be seen in the  FIG. 2 . Conduit  65  passes through a hole in plate  61 , (not numbered) to allow connection to other components in the overall system. 
       FIG. 3  is a cross section through stanchion  50   a  detailing additional structural and electrical features of the invention not shown earlier. Anchor blade  43  is shown passing through the bottom of housing frame  41  and additionally bonded to support blocks  49  inside of housing  40 . Fastener  43   b  is shown securing the assembly through holes  43   a . Ideally, the blocks, housing frame and anchor blade are connected by both adhesive bonding and dowel pinning with composite pins. 
     Similarly, post  61   a  is shown passing through plate  61  to secure the post to the base plate. Additionally blocks  61   b  to form a socket  61   c  for web sections  52   b . The lower joint is bolted by means of fastener  61   e  passing through the web sections  52   b  and post  61   a . Additionally, optional fastener  61   f  is shown passing through blocks  61   b , profile  51  and post  61   a . Alternatively, base  61  and stanchion  51  can be pre-assembled with adhesive bonding means and shipped to the field assembly site as a single unit. 
     A facing panel  74  is shown attached to composite profile  51  with screen module  72   a  and charging plug  72   b  of user interface  72  passing through it. Spring loading plug cover  72   c  is also shown in the figure. Wiring from both the screen module and the charging plug connects to controller  58  in the final assembly. 
     Facing panel  74  can be optionally surfaced with a narrow photovoltaic panel  124 , shown as a dash dot line in  FIG. 3  to supplement wind power in the summer and at other times of lower wind velocity. The connection to the charging system could either be through controller  57  or controller  58 . Photovoltaic panels  124  can also be placed on flange surfaces of stanchion  50  or appropriate surfaces of housing  40  based on the climatology of the site. 
     Both controllers  58  and  57  must connect individually to each of the batteries in the stanchion to adequately address the needs to charge and discharge power as needed. Additionally, control signals and communications functions between components must be wired to realize the design for the charging station. 
     Circuit board  75  is shown mounted in slot  53  of composite profile  51  to provide these connections through threaded posts  76  passing through web sections  52   b  to contact the appropriate wiring paths. Insulating supports  77  and  78  serve to align board  75  vertically in slot  53  while threaded posts  76  position and secure the board evenly between the web sections. Individual connecting wires  56   a  ( FIG. 2 ) are installed to posts  76  to complete connections between components. 
       FIG. 4   a  is a cross section through pultruded stanchion profile  51  illustrating the composite structure. In an application requiring both transverse and longitudinal strength outer layer  51   a  would typically be a triaxial stitched fiberglass fabric. Unidirectional glass roving layers  51   d  typically separate layers of glass fabric and a very useful in filling corner areas such as the one at the end of the indicating arrow of character  51   d . Both non-woven glass fabric and other glass fabrics such as stitched 0/90 fabrics can be used effectively in central layers  51   b  and  51   c . A variety of resin materials such as epoxy, urethane, phenolic, polyester and vinyls are often used, with urethane often being the choice for high strength constructions and phenolic resins being chosen for fire safe constructions. 
       FIG. 4   b  is a cross section through laminated composite base  61  showing multiple layers  61   g  preferably composed of woven glass fabric. Commonly, these ‘B-stage layers’ made from partially cured epoxy or phenolic resin systems that are cut, stacked and laminated in a high temperature, high pressure presses to complete the polymerization process and form laminated composite base  61 . 
     The resultant products have good bi-directional properties and compression strength for the application. Alternative reinforcement materials can include cellulose, other fibers derived from natural products and carbon fibers/fabrics, aramid and other high strength organic fibers and rock wool or fibers produced from lava. Although composite materials represent a preferred embodiment of stanchion  50  and base  61 , these components could as easily be fabricated from steel, another commodity metal or from properly reinforced concrete materials. Stanchions fabricated from metals would not, however, have the desirable non-conductive and chemically resistant properties that would be desired in the renewable energy charging station. 
     Mode of Operation: Vehicle Charging System 
       FIG. 5  is a process and instrument drawing (PID) illustrating operation of a vehicle charging system  80 . Direct current wiring is shown as dashed lines, communications and sensor signals are shown as dash-dot lines and solid lines indicate alternating current wiring. Within panel  44 , the voltage from generator  45  is adjusted, sensors and logic controls for operation of generator  45  are received and implemented. 
     Line  48  connecting to terminal  44   a  is the power supply from the generator. Line  91  connecting to terminal  44   b  is an encoder signal from the generator to monitor rotational rate and terminal  44   c  supplies braking control to the generator through line  92 . Terminal  44   d  of the panel communicates to both charging controller  57  and distribution controller  58  through data line  93 . Conditioned power output from panel  44  is supplied through line  47  to charging controller  57 . 
     Battery charging controller  57  is shown with connections to batteries  55   a  and  55   b  in the illustration although all the batteries in the stanchion assembly  50  are charged by controller  57  in practice. Battery  55   a  is shown with terminal  56   b  connected through switching relay  83  and battery  55   b  is shown with terminal  56   b  connected through switching relay  84 . 
     In cold weather, waste heat from generator  45  and housing  40  can be picked up by ducts  94  and transferred using a blower  95  through channels  96  to the storage battery area to maintain battery EMF in the face of lower outside temperatures. Conversely, excess heat from both the stanchion  50  and the housing  40  can be vented out of these enclosed areas in hot weather to prevent overheating of key electrical components. Charging gases, if present, from the batteries can also be automatically vented by the system. 
     In the charging mode of operation, control outputs from terminals  57   c  and  57   d  are supplied to relays  83  and  84  for connection of the batteries to DC supply terminals  57   a  and  57   b  of the charging programmer. In the discharging mode of operation, relays  83  and  84  connect terminals  56   b  of the respective batteries to distribution controller  58  at terminals  58   c  and  58   d . Controller  58  can discharge banks of batteries in voltages appropriate to the vehicle or energy end use connected by the demands on the system. 
     User interface display module  72   a  serves to advise the user of charging status at the stanchion and communicate credit card or other payment information to terminal  58   e  via data line  87 . Given adequate power reserves and payment, controller  58  supplies DC electrical charging power at terminal  58   h  to plug  72   b  through line  89 . 
     Other system needs and voltage requirements are evaluated at controller  58  based on communications from other parts of the system through port  58   f  connected to line  88 . While a connection to grid connected panel  73  is shown in  FIG. 4 , a connection to lamp stanchion  50   b  could also be enabled through controller  58 . In the illustration, DC voltage is supplied to panel  73  through line  90  from terminal  58   g . Alternatively, panel  73  could have supplied DC voltage rectified from AC supply  81  to stanchion  50   a.    
     Lightning protection for the electrical system is provided by line  82  routed to earth ground  82   g . The generator shaft is provided with pick up brushes  82   a  connected to line  82  as is the conduit system at  65  through collar  82   c . Generator case is connected at point  82   b  and the mast itself can be grounded through connection  82   d . Ideally line  82  is routed around the enclosure provided by composite profile  51  and cover plates  74  in the final installation to provide added safety to the components and the vehicles. 
     DETAILED DESCRIPTION 
     Blade Construction and Pivoting Mechanism 
       FIGS. 1 and 6  through  16  show a second embodiment of the invention in the form of a low cost, high strength turbine blade construction with an integral blade pivoting mechanism  106  and hub attachment means. Turbine blades  23  and  110  show the use of a flat, composite torsion members to replace the complex systems of pivot rods, springs and cams used in prior art such as Drees. 
     By reducing the cost and weight of composite turbine blades and using them in vertical axis wind turbine rotors  21  and  108 , savings can be achieved relative to HAWTs throughout the turbine including the rotor, housing, tower, support structure and assembly costs. 
     By simplification of the blade pivoting and assembly mechanism, good electrical generation efficiency with a more robust design for reduced maintenance can be achieved in areas with modest wind resources that are located in close proximity to where energy is being used. 
     Both of these improvements will lead to easily deployable, lower cost systems that can be mounted lower to the ground avoiding some of the restrictions and difficulties in mounting large utility grade HAWTs hundreds of miles from the point of use and hundreds of feet in the air. 
     The delays in creating transmission systems to move power across the country, the significant transmission losses and losses/costs associated with inverters to create AC power and later rectify to DC power for vehicle batteries can be avoided. 
       FIG. 6  is a cross section through blade  23  in  FIG. 1  showing a two part assembly made of pultruded composite materials as described in  FIG. 4   a . An unsymmetrical I beam  26  is bonded to an airfoil profile  29  using adhesive  29   a  to form blade  23 . Web section  27  of I beam  26  is integral to shorter flange portion  28   a  and longer flange portion  29   b . The center points of the two flange portions are offset from one another and the mid-plane of web section  27  to create a heel-in angle  29   h  relative to the plane of web section  27  and the tangent of the rotational motion  99  of blade  23  about mast  22 . Airfoil profile  29  is a cambered design similar to an NACA 4415 shape in cross section; but the invention is not intended to be limited to either this airfoil shape, a cambered design or a heel-in orientation in every application. 
     From a standing start and at low wind speeds, heel-in angle  29   h  allows blade  23  to add to rotational power when facing prevailing wind vector (arrow  100   b ) at blade position  101   b  in  FIG. 7  through an impeller type of response to the air flow. The heel-in angle also allows an aerodynamic lifting force, arrow  23 L, at startup in blade position  101   a  facing localized wind vector  100   a.    
     Test comparisons with an un-cambered blade design and with a cambered design having a heel-out configuration at position  101   a  relative to prevailing air-flow direction  101   b  showed a lack of self-starting characteristics for a turbine rotor of the type shown in  FIG. 1 . When the heel-in configuration was used in conjunction with a cambered blade profile, the turbine rotor was seen to have self-starting characteristics. 
       FIGS. 8 and 9  show the connection and blade pivoting system of the invention based on assembly drawings at hub assembly  25  in  FIG. 1 . Blades  23  a through d in the figure are tied to a molded hexagonal hub section  25   a  by fasteners  27 F.  FIG. 9  shows I beam  26  extending beyond airfoil profile  29  and trimmed of flange portions  28  in the area between profile  29  and hub section  25   a.    
     Web section  27  continues as flattened portion  27 P toward the hub and has a thickness  27 T, a width  27 W and a length  27 L in that area. Combined with the torsional properties of the pultruded web section, the dimensions of in that area can be used to fine tune the spring response, indicated by arrow  27 R of airfoil profile  29  to the centrifugal and aerodynamic forces on it. The torsional modulus of the material and the moment of inertia as defined by the flattened portion dimensions are chose so as not to exceed the elastic limit of the material under expected loads encountered, so that the blade will always return to the same rest pitch position after rotation. 
     Locking cap  25   b  with an integral molded fastener  25   c  is shown detached in  FIG. 8  and secured to hub section  25   a  in  FIG. 9 . As shown in  FIG. 8 , fastener  25   c  is inserted through hole  25   d  in the assembly process to secure the blades and I beams  26  a through d to hub section  25   a . At the end of each web section  27  a small ledge  27   g  is formed by an over-molding process after flange portions  28  have been trimmed. 
     Each trimmed web section  27 P fits into a rectangular slot  25   e  in hub section  25   a  with a ledge  27   g  fitting into with a deeper channel  25   g  during field assembly of blades  23  to hub sections  25   a . The field assembly is completed by inserting and tightening fasteners  27 F into threaded holes  25   f  at slots  25   e , securing non-blade struts  24   a  and  24   b  in a similar fashion and aligning/locking all six components to the plane of hub section  25   a  with locking cap  25   b.    
     Non-blade struts  24   a  and  24   b , as illustrated in  FIG. 8 , can have a more circular cross sectional profile compared to airfoil profile  29  to optimize strength to weight ratio and also be adapted to receive I beam sections (not numbered) similar to  26   a  to  d  for attachment to hub section  25   a.    
       FIGS. 13 and 14  show a materials arrangements for further reducing turbine blade cost which can be employed using the system.  FIG. 13  is a section through an alternate materials construction of the invention, with aerodynamic profile  29   e  of blade  23   e , connected to an assymetrical I beam  26   e  only at the ends of the blade. A light weight wood section  125  is bonded to profile  29   e  with adhesive  126  at the center of a blade span to transfer the load between the sides of profile  29   e  in that area. Wood varieties such as pine, fir, ash and hickory would be ideal in this application. 
       FIG. 14  illustrates a foam section  127  performing a similar function at mid-span of blade  23   f , with assymetrical I beam  26   f  shown in dotted lines behind. Any number of readily available foam systems with load transfer properties, such as urethane foams and styrene foams could be used to transfer the load between the sides of profile  29   f.    
       FIGS. 15 and 16  illustrate how the two part blade assembly might be used to introduce a twist into a uniform cross section blade, desirable in many small to medium sized horizontal axis blade turbines, (e.g. used in  FIG. 1 ). Referring to  FIG. 16 , chord line  103   a  of airfoil profile  29   g  in the foreground is shown as roughly horizontal, while chord line  103   b  in the background can be seen to be pitched upward at the trailing edge. 
     Assymetrical I beam  26   g  is shown in elevation in  FIG. 15 , with smaller flange  28   c  in the foreground and larger flange  28   d  behind. Beam  26   g  can be manufactured in a pultrusion process with flange  28   c  somewhat wider than shown in the figure. A shallow draft angle  128  (relative to the bottom of flange  28   d ) can be formed by linearly trimming flange  28   c  at the top and bottom. The spacing between contact points to the airfoil is maintained by the constant width of web section  27   h , while the trailing edge is forced upward by angle  128 . Profile  29   g  can then be produced by a thermoset system with some post cure (as is known for urethane pultrusions) or can be produced using a filled thermoplastic material or a thin, laminated material as shown in  FIG. 4   b , slid over I beam  26   b  and bonded in place. 
     A number of small and mid-scale applications for distributed power such as electrical generation in the 1 to 15 kilowatt range and water pumping using traditional multi-blade horizontals would be ideally suited to use of strong, lightweight, low cost blades as illustrated in  FIGS. 15 and 16 . 
     Mode of Operation: Blade Pitch Control System 
       FIGS. 6 and 7  illustrate the operation of a simple pivoting mechanism  106 .  FIG. 6  additionally shows a blade leading edge  29 C, a blade trailing edge  29 T with the center of mass of the blade located roughly at the arrow head of character  26 , (slightly forward of the center of web section  27 ). 
     Centrifugal force alone on the blade when the blade is at position  101   c  at higher rotational speed is prone to reduce the heel-in angle of blade  23 . The orientation of the blade at position  101   c  at high speed is shown in  FIG. 7  to have been influenced by pivoting action, arrow  102   c , being closer to a tangential orientation than angle  29   h  in  FIG. 6 . 
     A cross flow of air at higher rotational speeds due to a partial Magnus effect or other aerodynamic forces appears to shift the effective air flow direction from arrow  100   a  (slow speeds) to arrow  100   a ″ at blade position  101   a . As shown by arrow  102   a  in  FIG. 7 , this local cross flow tends to increase the heel-in angle at position  101   a  relative to that shown in  FIG. 6 . In turn, this reduces the angle of attack of blade  23  at position  101   a  at high speed, reducing the tendency to stall at that point. Arrow  100   e  in the figure shows by-pass flow of air further away from turbine rotor  21 . 
     By increasing the ratio of blade area to swept area, often called the solidity ratio of the turbine, this Magnus effect can be increased in the rotor design. In  FIG. 7  this factor is illustrated by the relative lengths of airfoil chord distance  103   c  and the open area between blades, length  103   o . While increasing drag at higher speeds, this approach can be used to fine tune the low wind speed response of the turbine to optimize performance in areas and installations with moderate winds. 
     An alternative interpretation of the cross flow phenomenon, not inconsistent with a Magnus effect, is slight pressure drop inside the circle of rotation of the blades due to the aerodynamic and frictional losses of the air flow passing the blades. Theories of operation are presented here to illustrate the performance of system as observed in testing. 
     Lift force at high rotational speeds from blade position  101   a , indicated by vector  23 L″, is likely to be a major component of the overall torque. Relative velocity of blade  23  to the local air flow,  100   a ″, is highest when the blade is approaching the prevailing wind  100   b  and the angle of attack may be favorable due to the increased heel-in angle. 
     At high rotational speeds with a rotor tip speed ratio greater than  1 , blade  23  at position  101   c  is moving faster than by-pass air flow  100   c . In  FIG. 7 , the blade can be seen as ‘flying upside down’ with a lower lift force  23 L′ (relative to  23 L″ at position  101   b .) Though the blade is not at an ideal angle of attack, the pitching motion indicated by arrow  102   c  has improved the angle of attack from what it might have been remaining at angle  29   h  shown in  FIG. 6 . 
     The pivoting effect at blade position  101   b  at high rotational speeds is indeterminate as indicated by double headed arrow  102   b . Deflection inward toward the mast by prevailing wind  100   b  is likely to be balanced by outward centrifugal force. At the mid-point heel-in angle shown in  FIG. 6 , the vector sum  100   b ″ of the rotational velocity and the prevailing wind  100   b  is likely to present an advantageous angle of attack for blade  23 . 
     By producing lift through about three fourths of the rotational cycle, (functionality at blade position  101   d  has not been analyzed) it is easy to see how Sicard, Drees and others achieved high aerodynamic efficiency in vertical axis turbines. The alternate embodiment of blade deflection system  106  shown in  FIGS. 10 through 12  applies the same type of composite torque spring mechanism to replace the more complex pivot rod, mechanical spring, cams used in the cylindrical rotor designs used in this area of the prior art. 
     DETAILED DESCRIPTION 
     Cylindrical Vertical Axis Turbine 
     An alternate embodiment of the invention using the blade pivot system  106  illustrated in  FIG. 7  is shown in  FIGS. 1 through 12 . While similar in overall geometry to the prior art of Drees/Sicard etc, the use of composite strip  115  in the pivoting of blades  110  represents a significant advance in terms of simplicity of operation, reduced parts cost and greatly reduced manufacturing costs. 
     Turbine rotor assembly  108  consists of upper and lower hoop sections  111  mounted to a central mast  109  by means of spokes  112  and mast junctions  113 . Capture of wind  107  by the turbine rotor results in mechanical rotation  123  which can be tied to a generator  45  as illustrated in  FIG. 2  or other driven devices based on the particular application. 
     Referring to  FIGS. 11 and 12 , each blade  110  is composed of an airfoil portion  114  which has a curved section  114   a  throughout most of its length and is flattened to a shape  114   b  which conforms to flattened composite strip  115  at each end. An adhesive  121  bonds the airfoil portion to the composite strip. An optional composite section  119  can be over-molded onto composite strip  115  where the transition between shape  114   a  and  114   b  occurs to prevent pull out of the strip during use. An optional rivet  120  can also be used to prevent pull out of strip  115  from airfoil portion  114 . 
     A metal U-bolt  117  is shown holding blade  110  in position against hoop  112 . Over-molded composite nibs  116  serve to position blade  110  at the proper level against hoop  112  and lock it in place. Nuts  118  are threaded onto U-bolt  117  to complete the assembly. Arrow  122  in  FIG. 12  shows the pitch deflection of the blade throughout the rotational cycle of rotor  108  in much the same way arrows  102  a through c illustrated the mode of operation in  FIG. 7 . 
     Composite strip  114  is preferably a high pressure laminate composite material saw cut from a larger sheet as described in  FIG. 4   b . Airfoil portion  114  is preferably an aluminum extrusion to allow for low tooling and materials costs for the cylindrical turbine. Hoops  111  can either be rolled metal or a specially formed high pressure composite laminate. Spokes  112  and mast  109  are preferably made from composite pultrusions as illustrated in  FIG. 4   a.    
     Like turbine rotor  21  in  FIG. 1 , turbine rotor  108  can be easily transported and assembled on site from a compact, light weight package. 
     DETAILED DESCRIPTION 
     Solar Array Supports and Panels 
       FIGS. 17 and 18  are detail drawings of the solar/structural array of  FIG. 1  and a typical solar structural panel  31 . Perimeter frame  32  has been removed from the view to see the structural attachments between the panels, the intermediate beams and the stanchion. 
     Hinged connector  35  consists of an anchor blade portion  35   a  which is set into a slot (as illustrated in  FIGS. 2 and 3 ) which continues up to receive a pivot pin  35   d . The blade portion passes through a lower flange  134  bonded to stanchion  50   d  and an upper flange  35   b  bonded to the anchor blade portion. Upper clevis plates  35   c  are attached to intermediate beam  33  and are fitted to the pivot pin in the field. Beam  33  is shown as a Tee shaped beam and is preferably made from a composite material as illustrated in  FIG. 4   a , but a metal beam is an acceptable alternative. The joint between the hinged connector and the stanchion is shown reinforced by bolts  133  between the upper and lower flanges. 
     Hydraulic cylinder  132   b  is used to pivot the deck about pin  35   d  and is attached to bracket  132   a  at the beam and bracket  132   c  mounted to stanchion  50   d . Dash dot line  131  indicates the bottom line of beam  33  when pivoted upward (arrow  130 ) by the action of cylinder  132 . 
     Solar structural panels  31  are pre-fabricated and pre-wired for the photovoltaic cells  39  attached to upper skin  135   a . The frame of the panel consists of upper skin  135   a  and lower skin  135   b  adhesively bonded to integral purlins  36   a  and  36   b  which receive cross braces  136 . Electrical output wiring  137  is shown passing through purlin  36   b  and in practice would lead into an inter-panel space  140  for routing to a conduit  138  which enters a voltage regulator and controller  139  mounted on stanchion  50   d . Controller  139  has the same function as panel  44  in the stanchion fitted with a wind system. A weather and UV light resistant cover sheet  38  is bonded to the panel and insulates/protects photovoltaic cells  39 . Cover sheet  38  is preferably made from polycarbonate, acrylic or polyvinylidene fluoride material. Since deflection resistance is provided by upper skin  135   a , the weight and cost of a glass cover sheet is not needed.