A tiered structural assembly for wind turbine blades that reduces stress on the airfoil profile is shown. The wind turbine blades and rotor assemblies for capturing the wind resources show significant improvements in both cost of manufacture and site assembly compared to three-bladed horizontal axis turbines. A simple, easily manufactured blade pivoting mechanism is shown to improve the performance of vertical axis turbines. A related improvement for varying blade pitch along the axis of horizontal axis turbine blades allows for production using continuous mass-production methods rather than the labor and cost intensive current practice of molding the blades. The blade assemblies are scalable and suited to areas with moderate wind resources.