Abstract: A method of health management of a monitored system includes collecting component condition indicator data used to calculate a plurality of component health indicators. Component fault severity and potential failure modes are determined utilizing the component condition indicator data. The potential failure modes are ranked in order of likelihood to isolate the failure mode. A system of health management for monitored apparatus includes a fault severity module to derive a plurality of component health indicators from collected component condition indicator data, the plurality of component health indicators indicative of fault severity of a plurality of components. A fault isolation module separately derives a ranked listing of potential fault/failure modes utilizing the component condition indicator data.

Abstract: A method of health management of a monitored system includes collecting component condition indicator data used to calculate a plurality of component health indicators. Component fault severity and potential failure modes are determined utilizing the component condition indicator data. The potential failure modes are ranked in order of likelihood to isolate the failure mode. A system of health management for monitored apparatus includes a fault severity module to derive a plurality of component health indicators from collected component condition indicator data, the plurality of component health indicators indicative of fault severity of a plurality of components. A fault isolation module separately derives a ranked listing of potential fault/failure modes utilizing the component condition indicator data.

Abstract: A computer-implemented method, system, and computer program product for virtual monitoring of aircraft fleet loads are provided. The method includes calculating virtual load data associated with an aircraft from a set of orthogonal waveforms. The method also includes calculating a set of coefficients as a function of parametric data and high frequency data associated with an aircraft. The method further includes storing the set of coefficients on the aircraft and transmitting the set of coefficients to a ground-based system configured to reproduce the virtual load data based on a copy of the set of orthogonal waveforms and the received set of coefficients in order to perform aircraft fleet management.

Abstract: A Health and Usage Monitoring System (HUMS) utilizes a common architecture which permits OEM and rotorcraft operators to view and trend HUMS data for an entire aircraft fleet independent of aircraft model, HUMS vendor, or raw data format. The system operates through a web portal that provides users with comparative information on HUMS parameters relative to fleet statistics. The user may view HUMS data for the entire fleet or drill down to a particular HUMS acquisition on a specific flight. The web based format also facilities display and communication of warnings in a timely manner.

Abstract: A computer-implemented method, system, and computer program product for virtual monitoring of aircraft fleet loads are provided. The method includes calculating virtual load data associated with an aircraft from a set of orthogonal waveforms. The method also includes calculating a set of coefficients as a function of parametric data and high frequency data associated with an aircraft. The method further includes storing the set of coefficients on the aircraft and transmitting the set of coefficients to a ground-based system configured to reproduce the virtual load data based on a copy of the set of orthogonal waveforms and the received set of coefficients in order to perform aircraft fleet management.

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: An unmanned aerial vehicle (UAV) has a toroidal fuselage and a rotor assembly having a pair of counter-rotating rotors secured in fixed coaxial combination with the toroidal fuselage to provide a vertical takeoff and landing (VTOL) capability for the UAV. One embodiment of the VTOL UAV is especially configured for ground surveillance missions by the inclusion of an externally mounted, remotely controllable stowable sensor subsystem that provides an azimuthal scanning capability and a predetermined elevation/depression scanning capability to accomplish the ground surveillance mission and a foldable landing gear subsystem to facilitate landing of the VTOL UAV at unprepared ground surveillance sites.

Abstract: One embodiment of a coaxial transmission/center hub subassembly for a rotor assembly having ducted, coaxial counter-rotating rotors includes a single stage transmission, a transmission housing, and a center hub support structure that are structurally and functionally interactive. The transmission housing includes upper and lower standpipe housings secured in combination with a middle housing. The single stage transmission includes an input pinion gear rotatably mounted in combination with the middle housing, and upper and lower spiral bevel gears rotatably coupled in combination with the input pinion gear to provide counter-rotation thereof. The spiral bevel gears include integral rotor shafts, respectively, rotatably mounted in the standpipe housings.

Abstract: A snubber assembly for a rotor assembly having ducted, coaxial counter-rotating rotors that is design optimized to facilitate utilization of a self-aligning bearing and for installation inboard of the corresponding flexbeam-to-rotor hub attachment joint, thereby enhancing accessibility and reducing maintenance costs. The rotor hub of the rotor assembly is design optimized for securing the snubber assembly in combination therewith and includes a plurality of arms, each arm forming an outboard clevis for attaching the rotor assembly flexbeam to the rotor hub. Inboard of the clevis, each rotor hub arm includes an outboard internal bulkhead having a bolt hole therethrough and an inboard internal bulkhead having a bolt hole therethrough. The inboard and outboard internal bulkheads in combination define a bearing cavity and an internal cavity for securing the snubber assembly in combination with the rotor hub.

Abstract: An unmanned aerial vehicle having a toroidal fuselage structure that surrounds a pair of coaxial, multi-bladed, counter-rotating rotors. The toroidal fuselage structure is optimized to provide a highly efficient structure for reacting aerodynamic flight loads and rotor thrust loads of the UAV. The toroidal fuselage structure is further optimized to provide weight efficiency for minimizing power requirements.

Abstract: A drive train assembly for a rotor assembly having ducted, coaxial counter-rotating rotors includes a sprag clutch, an engine coupling subassembly, a transmission coupling subassembly, and a drive shaft mechanically interconnected at the ends thereof to the engine and transmission coupling subassemblies, respectively. The drive train assembly is design optimized to maximize the functional capability of the sprag clutch, the engine coupling subassembly including an external crown spline coupling, internal spline coupling combination that is mounted in combination with the sprag clutch so that loads transmitted through the external crown spline coupling react through the center of the sprag clutch.

Abstract: An unmanned flight vehicle wherein two counter-rotating rotors are positioned within a toroidal fuselage and in which rotor pitch solely is utilized to generate all required lift, pitch, roll, yaw and vibration and stress control for the vehicle.

Abstract: A servo control system for a radio controlled co-axial rotor helicopter includes a receiver 4 to provide signals indicative of operator desired pitch, yaw, roll, and collective commands to an electronic mixer unit 30 which translates these command signals into six control signals 34-42 utilized by servos 50-60 to properly displace the rotor blades 256, 258.

Abstract: A progressive clutch includes a centrifugal clutch 10 attached to a drive shaft and inserted into a clutch housing assembly 16 to engage with clutch material 28 during low rpm operation. As the rpm of the input drive shaft 2 increases, the centrifugal force on pellets 32 overcomes the force of compression springs 34, and extension springs 40 pull a pin engagement assembly 30 towards the clutch housing assembly 16 thus engaging pins 38 into elongated holes 42 to provide positive drive from the drive shaft 2 to the driven shaft 21.

Abstract: A circulation control aircraft rotor blade of advanced composite material having a spanwise Coanda surface 16 and a plurality of spanwise extending flexible panels 18 cooperating with the Coanda surface to define slots for the discharge of compressed air from a duct 14 within the blade with each panel having flexure means 34 associated with attaching means 24 and limiting means 38 for establishing a slot opening preload and a slot maximum opening and with limiting means 38 providing structural equilibrium and reduced bending moments in the inboard corners of the air duct.

Abstract: A helicopter rotor system using composite flexbeams for connecting a rotor blade to the rotor hub, each flexbeam being of C-section and having a web section made up of 0.degree. and .+-.45.degree. plies and top and bottom flanges made up of low angle plies in the direction of their length with their ends being connected by an arc of plies so that the top and bottom flange plies are continuous with an attachment fitting encased at the ends of the flexbeams.