Abstract: An active control device is disclosed comprising an array of actively controlled oscillating air jets disposed on an aircraft structure. In a preferred embodiment, the device senses parameters associated with incipient unsteady aerodynamic excitation, such as free stream gusts, shed wakes in rotor and turbomachinery flows, or oscillatory motion of trailing edge control surfaces such as ailerons. These parameters are provided as input signals to a processor. Based on the input signals, the processor generates output signals that are used to operate the air jet array in a manner counteractive to the unsteady forcing. The air jet array can be used on numerous aircraft structures, including rotor blades, wings, engine inlets, engine exhausts, blunt surfaces and nozzles.

Abstract: A porous surface on an aircraft structure driven with oscillating positive and negative pressures is used as an active control device for attenuating negative aerodynamic interactions. The porous surfaces can be driven with positive and negative pressures either continuously or when predetermined flight conditions are present. The porous surfaces can be used on rotor blades to reduce BVI noise in descent flight conditions. The porous surfaces can be configured on rotor blades for affecting blade variable twist in accordance with various flight conditions, and can further be incorporated for reducing rotor hub vibrations as well. Porous surfaces placed on aerodynamic surfaces below the rotor blades of a tiltrotor aircraft can attenuate or eliminate download and fountain flow conditions.

Abstract: A method for acquiring and assembling software components at execution time into a client program, where the components may be acquired from remote networked servers is disclosed. The acquired components are assembled according to knowledge represented within one or more acquired mediating components. A mediating component implements knowledge of an object model. A mediating component uses its implemented object model knowledge, acquired component class information and polymorphism to assemble components into an interacting program at execution time. The interactions or abstract relationships between components in the object model may be implemented by the mediating component as direct invocations or indirect events or software bus exchanges. The acquired components may establish communications with remote servers. The acquired components may also present a user interface representing data to be exchanged with the remote servers.

Abstract: A bulk absorber has a continuous concentration gradient of particles with dielectric or magnetic altered properties. The bulk absorber may be made from foam or, ceramic. The particles may be carbon fibers, carbon black, carbon whiskers, coated hollow microspheres, or a combination thereof. A manufacturing system for fabricating a bulk absorber has two delivery devices, a controller, an intermingling device, a positioning device, and a forming device. The delivery devices produce flows of absorber precursors, with at least one of the flows having a concentration of particles having dielectric or magnetic altering properties. The ratio of the flows is controlled by the controller. The intermingling device receives and mixes the flows to produce a combined flow. The particle concentration in the combined flow is controlled by the controller. The positioning device directs the depositing of the combined flow into a cavity to build a non-solidified item.

Abstract: A lightweight, three dimensional structural article having low radar reflectivity characteristics and good mechanical properties is fabricated from a syntactic foam core having a structural outer skin. A syntactic foam sealing adhesive film is applied to the surface of syntactic foam core and under the outer skin to both seal the foam core and adhere the outer skin. The syntactic foam sealing adhesive is formulated to provide a uniform layer and to reduce the fabrication time and labor while improving the overall radar absorbing characteristics of the structural article.

Abstract: A lightweight, three dimensional structural article having low radar reflectivity characteristics and good mechanical properties is fabricated from a syntactic foam core having a structural outer skin. A syntactic foam sealing adhesive film is applied to the surface of syntactic foam core and under the outer skin to both seal the foam core and adhere the outer skin. The syntactic foam sealing adhesive is formulated to provide a uniform layer and to reduce the fabrication time and labor while improving the overall radar absorbing characteristics of the structural article.

Abstract: A composite structure is made by first furnishing a skin layer made of a composite material of quartz fibers embedded in an uncured cyanate ester-resin matrix. A transition layer of a first epoxy resin is applied to the skin layer. The skin structure including the skin layer and transition layer is cured at a first temperature and post cured at a second temperature greater than the first temperature. A bonding layer of a second epoxy resin is thereafter applied to the bonding surface of the transition layer, and a substrate is contacted to the exposed face of the bonding layer. The second epoxy resin is cured at a third temperature no greater than the first temperature.

Abstract: Porous surfaces on an aerodynamic structure driven with positive and negative pressures are used in an active control system for attenuating shock waves responsible for high-speed impulsive (HSI) noise. The control system includes an array of apertures in the outer skin of the structure providing fluid communication between the exterior flow stream and an interior volume of the structure. A movable diaphragm within the structure pushes air out of and pulls air in through the apertures under the action of a drive mechanism within the structure, thus creating oscillating air jets. The drive mechanism may be actuated by a controller based on information supplied by a sensor in the leading edge of the aerodynamic structure. The array of apertures may be spaced apart along the outer skin of the aerodynamic structure so as to span a distance of about 15% of the chord length. The oscillating airjets may be provided on multiple surfaces of the aerodynamic structure, including the upper and lower surfaces.

Abstract: An R-foam having a surface with an electrically resistive ink layer that is continuous and an electrically conductive ink layer that is in a predetermined pattern. The resulting surface is thereby electrically modified to have a predetermined resistive taper across it according to a predetermined resistivity curve. The method of manufacturing the R-foam involves printing the ink layers to the surface in a predetermined pattern that results in the predetermined resistivity curve. The ink layers may be applied using silk screening, stamping, and ink jet printing techniques.

Abstract: The present invention comprises a feedback-controlled braking apparatus that applies a modulated braking force that smoothly decelerates a rotating shaft such that it comes to rest at a precise location. According to a preferred embodiment of the present invention the rotor hub of a rotor/wing aircraft is coupled to a hydraulically actuated friction brake, such as a conventional disk brake. The disk brake caliper is supplied with fluid pressure from an electrically actuated servo valve which, in turn, is controlled by an electronic controller. A sensor monitors the angular position and velocity of the rotor main shaft. The velocity and position information is provided to the controller, which modulates the brake pressure as required to bring the rotor to a stop at exactly the right orientation relative to the aircraft.

Abstract: The present invention comprises an apparatus for locking the pitch axes of the rotor blades of a rotor/wing aircraft so as to form a rigid wing. In one embodiment of the present invention the rotor blades of a rotor/wing aircraft are locked to each other to form a rigid wing assembly having a common pitch axis. This wing assembly is then locked in position about its pitch axis by means of a pitch lock apparatus that engages the lower end of the pitch link of the rotor blade that is oriented at the leading edge of the fixed wing. In another embodiment each rotor is independently locked about its respective pitch axis by means of two separate pitch lock apparatus. By locking the rotor blades into a rigid assembly by means of an independent rigid pitch lock apparatus, it is possible to provide a rotor/wing aircraft having a fixed wing with more predictable and controllable response to aerodynamic forces.

Abstract: A hydraulic damper assembly has a barrel-piston assembly and a spring assembly. The barrel-piston assembly has a barrel with a top portion having an open end, and a piston extending through the open end. The piston has a bottom portion that is located inside the barrel. The piston and the barrel also define an annular space in which is a barrel shoulder and a piston shoulder. The barrel shoulder radially extends into the annular space from the barrel top portion. The piston shoulder radially extends into the annular space from the piston bottom portion. The spring assembly is disposed in the annular space between the barrel shoulder and the piston shoulder. When the piston is extended from the barrel, the shoulders compress the spring assembly and, thereby, reduce the amount of force required to compress the piston which enables the damper to be charged to a higher nitrogen pressure.

Abstract: The present invention comprises an apparatus for locking both rotor blades of a rotor/wing aircraft at a common point to form a rigid wing having a uniform bilateral aerodynamic response. In one embodiment of the present invention the rotor blades of a rotor/wing aircraft are locked together to form a rigid wing assembly. This is accomplished by locking the blades together by a locking mechanism that engages when the rotor speed drops below a certain threshold. With the rotor blades locked together, the wing assembly can then be locked in position with the appropriate pitch angle simply by securing the pitch link of the rotor blade that is oriented at the leading edge of the fixed wing. In another embodiment of the invention the blades are locked directly to the rotor by two locking mechanisms that engage the hub directly.

Abstract: A precision grinding apparatus includes a grinding worm for precision grinding a case-hardened face gear. A shaper is first placed into contact with a face gear, to thereby shape a surface of the face gear into a plurality of face gear teeth. The shaper is then removed, and the face gear is case hardened. The grinding worm is disposed in a normal orientation to the case-hardened face gear and includes a spiral tooth extending along a perimeter of the grinding worm. The spiral tooth of the grinding worm is adapted to contact and precision grind the case-hardened gear. A dressing tool includes a protrusion for contacting the spiral tooth of the grinding worm, as the spiral tooth contacts and precision grinds the case-hardened face gear. The dressing tool thus maintains the shape of the grinding worm to within a desired tolerance range.

Abstract: An actively controlled helicopter rotor blade includes a trailing edge flap actuated by a fast-acting actuator. A lightweight, rugged, fast-acting actuator suitable for use as the flap actuator comprises a pair of column actuators composed of a smart material such as piezoelectric, magnetostrictive, shape memory alloy or other material that exhibits a shape change when subjected to an external stimulus. Each of the column actuators is composed of multiple piezoelectric ceramic actuator elements bonded together to form the individual columns. Each of the column actuators engages the base of an actuator tube that, in turn, is urged against the column actuators by a tension member. Differential voltage applied to the columns causes a differential elongation of the column actuators, which causes the actuator tube to pivot about an axis proximal the tips of the column actuators. The movement of the actuator tube is coupled by a linkage to the rotor blade flap.

Abstract: An articulating and telescoping duct is provided for use in a helicopter reaction drive flow path for ducting the exhaust and/or bypass gases from the aircraft engine into the flow ducts of the rotor blades. In a preferred embodiment the telescoping duct comprises a tubular member having a bead formed at each end. Each of the beads has an outside surface formed into a spherically curved sector that is centered radially about the axis of the tubular member. The receiving duct at one end comprises a complementary spherical bore that seals against and retains the spherical outside surface of the tubular member while permitting the tubular member to articulate relative to the receiving duct. The receiving duct at the other end comprises a complementary cylindrical bore that seals against the spherical outside surface of the tubular member while permitting the tubular member both to articulate relative to and telescope in and out of the cylindrical bore.

Abstract: An active control system for reducing blade-vortex-interaction (BVI) noise generated by a rotor blade. The active control system includes a pressure sensor assembly, a device for changing a lift generated by the rotor blade, and a controller for activating the device upon a detected change in air pressure by the sensor assembly. The sensor assembly is disposed in close proximity to the rotor blade, and is adapted to detect a change in air pressure on a surface of the rotor blade near a leading edge of the rotor blade. The device is adapted to be activated by the controller, to thereby change a lift of the rotor blade. The controller activates the device to change a lift of the rotor blade in order to introduce a compensating pressure onto the surface of the rotor blade. This compensating pressure attenuates the magnitude of the change of air pressure.

Abstract: A composite structure is made by first furnishing a skin layer made of a composite material of quartz fibers embedded in an uncured cyanate ester-resin matrix. A transition layer of a first epoxy resin is applied to the skin layer. The skin structure including the skin layer and transition layer is cured at a first temperature and post cured at a second temperature greater than the first temperature. A bonding layer of a second epoxy resin is thereafter applied to the bonding surface of the transition layer, and a substrate is contacted to the exposed face of the bonding layer. The second epoxy resin is cured at a third temperature no greater than the first temperature.

Abstract: A portable three-dimensional position and velocity data archiving system for use with an aircraft during flight testing and evaluations. The system includes a ground based system and an airborne system. Each system includes a GPS receiver electrically connected with a GPS antenna for receiving and interpreting GPS signals transmitted from a GPS satellite constellation. Each system also includes a radio communication device for transferring position and velocity data as well as error correction data and guidance cues between the ground and airborne systems. The portable system acquires, processes, archives, and provides precise three-dimensional position and velocity data for the aircraft in real time. Information regarding aircraft position, direction, velocity, acceleration and any correction needs referenced to a selected coordinate system is immediately presented to a vehicle piloting crew on analog as well as digital indicators.

Abstract: A flap lock device for restraining the flapping movement of a main rotor blade assembly on a helicopter. The flap lock device includes an first elongate frame member which extends between a first end and a second end and second elongate frame member which also extends between a first end and a second end. A pivot connection pivotally connects the first end of the first frame member with the first end of the second frame member. An outwardly facing contact pad is coupled to each of the frame members and adapted for contact with various positions on the helicopter. An actuating device interconnects the first and second frame members and is used to forcibly move the contact pads outwardly and into contact with the helicopter. The flap lock device is installed between the main rotor blade assembly and the main rotor assembly to forcibly maintain the main rotor blade assembly against the droop stop mechanism.