Derived from a design approach for a new wing known as PRANDTL-D, this technology achieves similar improvements for propellers and other rotating machinery.
To achieve the innovation's alternate spanload, Armstrong designers applied a non-linear twist to the propeller blade. The twist moves the load inward and dissipates the tip vortex over a wider area, minimizing its effect on drag. It also results in a decrease in load at the tip and reduced torque at the tip. These changes combine to achieve a dramatic reduction in power consumption without compromising the blade's other parameters. Specifically, the blade's diameter and rpm remain unchanged.
Unlike the conventional minimum induced loss (elliptical) spanload, which consumes large amounts of power at the tip of the blade, the new design unloads the tip and reduces torque, achieving significant improvements in efficiency. Firstorder analysis shows a more than 15 percent improvement in power consumption while producing the same thrust. The design also produces significantly less noise than conventional blade designs.