A numerical method is used to evaluate the influence of propeller parameters on the aerodynamic performance of shrouded coaxial dual rotors in hover. Compared with the open-rotor configuration. the shrouded rotors reduce the tip vortex. resulting in a higher thrust and figure of merit (FoM). https://www.jmannino.com/quick-save-Canon-imageCLASS-MF227dw-Monochrome-Multifunction-Laser-Printer-great-choice/