| 主权项 |
1. A wind turbine for operation within a circular area comprising:
a set of curved blades mounted on a central rotatable hub, each of said blades having a length from the hub to the tip and a wind contact surface defined by a leading edge and a trailing edge and a defined pitch angle, to a rotational axis of the hub, along at least a portion of the blade from the hub to the tip such that said at least a portion of said blade passes through at least 85 percent of said circular area; a curve on the wind contact surface along said at least a portion each of said blades having an increasing pitch angle of the blade, over the blade surface from the leading edge of the blade to the trailing edge of the blade by an amount between about 6 and about 24 degrees; said defined pitch angle from any point along said leading edge of said at least a portion of said blade being defined by the arc-sine of a ratio of blade velocity to apparent wind velocity, with a variance of ±30 percent of the complementary angle to said arc-sine; and apparatus for varying the velocity of the blade to control power output so that it is within fifteen percent of maximum obtainable power; provided that, said pitch angle is at least 20 degrees and not greater than 85 degrees, and provided that the pitch angle closest to the hub, of said at least a portion of the blade, is at least fifteen degrees less than the pitch angle of said at least a portion of the blade most distant from the hub. |
