The unmanned wings fly in a circular flight path, controlled by a computer. Electricity generated by the rotors travels down the tether, eliminating the need for the massive cement towers holding traditional wind turbines.
In February 2012 the turbine performed three transitions in and out of crosswind flight as required the US Department of Energy's ARPA-E grant. In crosswind flight mode the turbine flies in large, vertical circles. The main wing creates lift, keeping the wing aloft, while an onboard computer keeps it flying in a circle. Meanwhile, four rotors on the main wing slow the wing down while generating power, like the brakes on a hybrid car. For more on how the wings keep aloft, click here.