Why do industrial large ceiling fan blades adopt variable section design?

As a large industrial ceiling fan manufacturer, not only has developed and produced different series of fan products with complete specifications, diverse functions and suitable for a variety of occasions, but also has its own security patents: safety connection patents and safety fan blade patents. The fan safety patent includes the fan blade variable section streamlining design and the fan aluminum alloy master plate bending. The fan blade of the industrial large ceiling fan adopts the variable section streamlining design, do you know why?
Relative to the variable section of the fan blade, there are many manufacturers of the fan blade is equal cross section, commonly said is the plane fan blade, although the inclination of the fan blade and the width of the fan blade are very large, but in the rotation of the fan blade to push the air, will make the fan wind resistance coefficient is large, therefore, at the same speed, the fan blade requires the motor torque is greater, it is more expensive, more prone to fracture risk.
The variable section streamlined fan blade, designed according to the equal chord length theory, moves from the center point to the tip along the blade length direction, the blade width gradually Narrows (due to the gradual increase of the linear speed of the point), and the width from the root to the tail is 29.8~19.2 cm. Due to the aerodynamic principle, the fan blade is subjected to less resistance, and more air is pushed at the same rotational speed. More air volume. It can ensure that the wind is evenly discharged in the direction of the entire blade extension, and there is no hole in the middle, improve the wind efficiency, and the most important thing is to ensure that the force of the fan blade is balanced and not broken.
Of course, to ensure the overall safety and wind efficiency of large industrial ceiling fans, not only lies in the variable section of the fan blade streamline design, after many tests and reasonable calculations, the large ceiling fan blade automatically rises 3°~ 6° when running, which is based on the Bernoulli principle, due to the design of the fan blade upward Angle, It can also make the ceiling fan remove the great lifting force and wind resistance during operation, reduce the torque borne by the deceleration motor, and ensure the smooth and safe operation of the ceiling fan as a whole.