Abstract: An improved wind energy machine for capturing the wind to produce useful work, such as generating electricity. The wind energy machine has a rotating center hub with a center drive shaft and a vertical axis disposed therethrough. An output shaft is attached to or integral with the drive shaft. Extending outward from the center hub are a plurality of arms that each have an arm support structure comprising a plurality of frame members. The arms rotate the center hub and drive shaft. Pivotally attached to each arm support structure is at least one sail structure that supports a sail. The sail structures pivot to close the sails and engage the wind on one side of the machine and open to allow the wind to pass through on the opposite side. In a preferred embodiment, a pivoting kicker sail provides additional rotation action and a shroud structure helps trap the wind.