depicted in fig1 to the wind direction is shown by vector arrow 975 the tower may be rotated in response to changes in the wind by use of a yaw motor or other device also illustrated is the space 136 between the leading and trailing edges it is this space that is covered by the secondary load bearing material see fig2 and 4 see fig2 a comprising a cross sectional top view of the tower structure illustrated are the leading edge 110 and trailing edge 120 side panels 135 and the narrow profile of the tower structure facing the wind 975 the leading edge defines the narrow profile referencing fig1 because the tower edge separation profile is similar to the linear moment profile from rotor thrust loads in the leading and trailing edges are fairly constant and therefore a good match to a constant material cross section related to this is that primary structural shear in the side panels and fasteners is low the side panels may be a composite material there will be kick loads at the kink 130 in the trailing edge load path but the mid tower collar 230 is installed at this location and may reinforce the trailing edge also interior structure such as wide flanges or a bulkhead integrated into the joining of upper and lower tower sections may be used to react to these kick loads in the embodiment illustrated in fig1 the tower edges achieve maximum divergence approximately in the midpoint 130 131 of the structure 100 i e mid tower this forms a kink or widest portion of the wing shaped tower structure an upper bearing assembly 220 reacts the net loads from the two.