Abstract: An unmanned aerial vehicle that includes a fuselage with a partial toroidal forward portion, and an aft portion. A duct is formed through the fuselage and extends from the top to the bottom of the fuselage. Two counter-rotating rotor assemblies are mounted within the duct for providing downward thrust through the duct. The rotor assemblies are supported by a plurality of support struts. At least one engine is mounted within the fuselage and engages with the rotor assemblies. A pusher prop assembly is mounted to the aft portion of the fuselage. The pusher prop assembly is designed to provide forward thrust along the longitudinal axis of the aircraft. The pusher prop assembly includes a drive shaft that is engaged with the engine. A plurality of propellers are attached to and rotated by the drive shaft. A shroud is mounted to the aft portion of the fuselage around the propellers and is operative for channeling the air passing through the propellers in a substantially aft direction.

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

Abstract: A connecting assembly interconnects one fiber optic cable harness to another fiber optic cable harness, or to an electronic unit containing an optical transmitter or receiver. The backshell includes a coupling ring that prevents loosening of the connection without first relaxing tension on the individual fiber optic cables in the cable harness. The inability to rotate the connector end coupling ring before relaxing tension on the fiber optic cables prevents damage to the individual fiber optic cables from occurring when the backshell is rotated with respect to the connector.