Side-furling co-axial multi-rotor wind turbine

A wind turbine, comprising:

• a series of substantially horizontal axis type rotors attached in a substantially coaxial manner at spaced intervals along a driveshaft;
• said driveshaft aimed sufficiently parallel to the wind for the rotors to effectively harness the wind, but at an offset angle from the wind direction, sufficient to allow an admixture of fresh air, substantially undisturbed by upwind rotors, to each rotor;
• said driveshaft held in a rotationally free, cantilevered manner, by a cantilevered bearing means from which it projects;
• wherein at least part of said driveshaft projects from said cantilevered bearing means substantially toward the wind;
• wherein said offset angle is in the horizontal plane;
• said wind turbine further comprising passive means to maintain a heading at said offset angle from the wind direction during normal operation.

A method

• for mounting a plurality of horizontal axis wind turbine rotors on a building having a top surface;
• for providing freedom for each of said rotors to rotate on its own axis;
• for providing directional freedom to collectively aim said rotors in any direction in response to the wind,
• for mechanically coupling, in a manifold fashion, all said rotors to drive one load,
• for preventing strikes of the building by the blades of said rotors,
• and for providing fresh wind to each rotor, substantially undisturbed by upwind rotors, so that all rotors contribute power to drive the load,
• comprising the following steps:
• providing a yaw bearing means proximate said top surface of said building;
• providing a bearing support means mounted on said yaw bearing means;
• whereby said yaw bearing means provides rotational freedom to aim said bearing support means;
• providing at least one bearing mounted on said bearing support means;
• providing a driveshaft mounted in said bearing;
• whereby said bearing allows said driveshaft to rotate about the longitudinal axis of said driveshaft;
• whereby said driveshaft may be aimed in any direction;
• whereby said driveshaft has sufficient length to overhang the periphery of said top surface of said building, whatever direction said driveshaft may aim;
• mounting said rotors on said driveshaft, said rotors separated by at least one spaced interval,
• said interval being of sufficient magnitude to provide sufficient clearance between said rotors and said building, whereby said rotors do not strike said building, whatever direction said driveshaft may aim;
• aiming said driveshaft at an offset angle alpha to the wind direction
• whereby each of said rotors is so placed, in relation to the wind direction and other said rotors, to substantially avoid the wake of other said rotors, and is thereby exposed to fresh wind, substantially undisturbed by upwind rotors, so that all rotors can substantially contribute to the rotation of the driveshaft, and;
• coupling a load to said driveshaft;
• whereby said driveshaft drives said load.