Isn there a large drag on the tower structure?
At the critical survival wind speed design point, the turbines are vectored out of the wind. Relative to an equivalent projected area truss tower, WARP drag forces are actually much lower. The lower drag stems from a lower profile drag coefficient of an aerodynamic surface such as WARP relative to that of a truss. During turbine operation, lower drag load stems from the flow separation delay generated about WARP modules by the operational rotors. The latter create a smaller wake off the tower, hence, smaller drag coefficient. Unlike a large diameter wind turbine of equal power which has all its load concentrated at the rotor hub near the tower apex and which must be reacted at the tower base, a WARP has its load well distributed along its height and can be reacted efficiently and cost effectively by a smaller foundation and guy wires.
