US Patent 10315757 Propeller blade beta twist

A propeller blade comprises a blade root coupled to a rotor hub and a blade tip. The propeller blade is composed of airfoil cross-sections, each cross-section a distance away from the rotor hub. Each airfoil is designed with particular structural characteristics that improve the overall amount of thrust generated on the quadcopter. Namely, each airfoil possesses a β angle and chord length whose values depend on the distance of that airfoil from the rotor hub. For example, the relationship between an airfoil's β angle and its distance from the rotor hub is described by a power law. Additionally, the relationship between an airfoil's chord length and its distance from the rotor hub is described using a polynomial regression. Compared to current, off the shelf propeller blades, the current propeller blade embodiment achieves the same thrust at a lower RPM, thereby yielding benefits in reduced acoustic noise and improved response time.