Patent ID: 8074918

Claim:
A method of operating an unmanned aerial system, comprising: providing an unmanned aircraft with a fuselage and wings, the unmanned aircraft including an electric ducted fan engine for propulsion, the electric ducted fan engine is mounted axially in the fuselage and includes an axial duct with a front end defining a fluid intake, a rear end defining a fluid discharge, an impeller at the front end for drawing fluid into the axial duct, and guide vanes disposed adjacent to the rear end of the axial duct that de-swirl fluid before it is discharged through the fluid discharge, the electric ducted fan engine is driven by an electric motor; disposing the unmanned aircraft in water and using the electric ducted fan engine to propel the unmanned aircraft in the water; and launching the unmanned aircraft from the water and using the electric ducted fan engine to propel the unmanned aircraft to fly through the air.