Propeller with unloaded tip region and method

The present disclosure provides a rotary propeller design that maintains high efficiency and reduces noise. The design provides a non-loaded tip region of positive lift starting before the end of the tip, with negligible (if any) positive lift, which violates intuition for the purpose of the propeller. The unloaded tip region reduces the strength of tip vortices and reduces induced resistance. The result is a significant reduction in noise while maintaining comparatively high mechanical efficiency even if the RPM is optionally increased to compensate for reduced lift without the need for longer propellers. At least one propeller design may disconnect a beta angle from the propeller hub at a different beta angle at a first location from the hub and then also disconnect the beta angle into an unloaded tip region at a second location away from the hub to form a dual fracture propeller. 本公开提供了一种保持高效率并降低噪声的旋转螺旋桨设计。该设计提供了在末端的端部之前开始的正升力的无加载末端区域，其具有可忽略的(如果有的话)正升力，这对于螺旋桨的目的是违反直觉的。无加载末端区域降低了末端涡流的强度并减小了诱导阻力。结果是噪声显著降低，同时