METHOD OF REDUCING A NOSE-UP PITCHING MOMENT IN A DUCTED ROTOR UNMANNED AERIAL VEHICLE

摘要

A method for reducing a nose-up pitching moment in an unmanned aerial vehicle (10) during forward flight. The unmanned aerial vehicle includes counter-rotating rotor assemblies (38, 40) that are mounted within a duct (18). Each rotor assembly (38, 40) includes a plurality of rotor blades. The method involves adjusting the rotor blades to have substantially zero pitch. Then rotating the rotor asemblies (38, 40) to produce a virtual plane (62) across the duct (18). The virtual plane (62) is operative for substantially deflecting air (70) passing over the fuselage (44) away from the duct (18). In one embodiment of the invention, the method involves the further step of obstructing at least a portion of the bottom of the duct (18) to inhibit air (70) that is flowing across the bottom of the duct from passing into the duct (18).