What makes Wind Turbine’s Rocky Flats design such a departure is not only its hinged blades, but also their downwind orientation. The Danish design faces the blades into the wind and makes the blades heavy so they won’t bend back and slam into the tower. The Wind Turbine design can’t face the wind—the hinged blades would hit the tower—so the rotor is positioned downwind. Finally, it uses two blades, rather than the three in the traditional design, to further reduce weight. ... Advances in the computer modeling of such dangerous forces as vibration helped the design’s development. Flexible blades add an extra dimension to the machine’s motion; so does the fact that the whole machine can freely swivel with the wind.