Surviving the Bear Market, Drones for Intra-hospital Transport, Airframe Optimization for Medical Use Cases, Co-axial Rotor Performance & more
My comment is to item #2: Hover-Propeller Full Design Cycle - Performance and Acoustic
My full respect to the expertise and efforts described in the report. Just want to hint at a new potential approach to reducing propeller noise. It is through application of variable twist blades. Variable blade twist provides a quasy constant level (high level!) of propeller efficiency for a changing axial speed. High efficiency, theoretically, ensures low level of wasted energy, which may manifest in silent operation.