Fixed pitch wind power '> wind turbines'> small wind turbines is the main structural features: the blade and hub connection is fixed, that is when the wind speed changes, blade angle can not change with the wind. The characteristics of a given pitch wind turbine '> wind turbine proposed two must be addressed. 

 First, when the wind speed above the design point of the wind wheel is rated wind speed, the blades must be able to automatically limit the power rating in the vicinity, because the wind generator  on the physical properties of all materials is limited, this blade properties known as the automatic stall performance. Second, in the operation of wind turbines '> wind turbine at the sudden loss of power (sudden load rejection) of the case, the blade itself must have braking ability, so wind turbines'> wind turbine generator to the security situation in the wind downtime. Early fixed pitch wind turbine '> wind turbine wind turbines do not have the braking ability, off-grid installed when relying solely on low speed or high speed shaft of the mechanical shaft brake to brake, which for tens of kW units is not a big problem, but for large-scale wind generators '> wind turbine, if only the use of mechanical brakes on the whole structure would have a serious impact strength. To solve the above problem, blade manufacturers in the 20th century the first 70 years of glass fiber reinforced composite materials, the successful development of the stall vertical  wind turbine blades with good performance to solve the fixed pitch wind turbine '> when the wind turbines in wind power control problem; of the 20th century tip spoiler 80 in turn successfully applied to wind turbines'> wind turbine, the solution reduce the load in case of sudden shutdown problem of security, so that fixed pitch (stall type) wind generator '> wind turbines in the past 20 years, the development and utilization of wind energy has always been dominant, the latest release of the megawatt-class wind turbines'> wind turbine models are still using the technology.