Abstract: An actuation system for pivoting a flap on a helicopter rotor blade to reduce the interaction of the blade with the preceding blade vortex. The actuation system includes a fluid supply which is connected to first and second fluid supply lines. The fluid supply lines convey flows of pressurized fluid from the fluid supply to an actuator. The actuator includes a housing mounted within the rotor blade and having a channel formed in it. A butterfly shaft is pivotally mounted within the channel and has laterally extending arms which separate the channel into four lobes. A first port connects the first fluid supply line with two diametrically opposed lobes in the channel. A second port connects the second fluid supply line with the other two diametrically opposed lobes in the channel. A torque coupling is attached to the butterfly shaft and engaged with the flap such that rotation of the torque coupling produces concomitant rotation of the flap.

Abstract: An assemblage for bonding the skin of an airfoil to the core of the airfoil includes a hybrid caul plate assembly for covering the surface of the airfoil assembly which is exposed to bonding pressure. The hybrid caul plate includes a central elastomeric component and peripheral semi-rigid metal components. The semi-rigid metal components are formed from a steel sinusoidal mesh and are axially elongated. The mesh is flexible in the direction of elongation, but are rigid in the transverse direction. The peripheral semi-rigid caul componnents will thus closely conform to the contours of the core in the axial direction, and will, at the same time, provide support for the edges of the core so that the core edges will not be crushed or deformed by bonding pressure applied to the assemblage during the skin-to-core bonding process. The result of using the hybrid caul plate assembly is an improved skin-to-core bond wherein bridging or voids in the bond line at the periphery of the airfoil are avoided.

Abstract: An aircraft door is slidable along a door path between open and closed positions. The door is guided by one or more tracks. Riders carried by the door are engaged to the tracks. Each rider includes a roller held for rotation about a roller axis which is fixed relative to the door. Each roller axis extends generally horizontally and generally transverse to the track. Each track includes a first portion extending generally parallel to the aircraft fuselage and a second portion having a continuously curving transition to the first portion and extending partially inboard from the first portion. The second portion of the track guides the door into and out of the opening in the fuselage, allowing the door to achieve a substantially flush condition when in its closed position.

Abstract: A feedback system for reducing the effects of destabilizing forces in a vehicle (e.g. helicopter) by utilizing acceleration feedback data sensed by an acceleration sensor located in the vehicle. This sensed acceleration signal is passed through a low-pass filter and combined with a command signal to produce an error signal. The error signal is multiplied by a predetermined gain to produce a corrective signal that is utilized by actuators to adjust an adjustable surface, such as a swashplate, on the vehicle.

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 technique for providing a signal representative of blade vortex interaction (BVI) noise for a multi-blade rotorcraft. The fluid (air) pressure at one, two, or more predetermined locations on a rotor blade is measured during at least one predetermined azimuthal segment of blade rotation during operation to provide respective pressure measurements. The pressure measurements are processed to provide a signal for use as a control variable in a control system for the active control of BVI noise. The pressure measurements are made within 10% blade chord length of the blade leading edge and preferably two or more are made between 65% and 95% of blade radial-length. The pressure measurements are filtered and the band of retained frequencies is between 20 and 48 times the rotor rotation frequency. An algorithm operative over a determined blade frequency range optimizes the signal for control use.

Abstract: A cabin interior assembly for an aircraft is disclosed, the aircraft having a primary airframe structure for supporting vibrating components. The cabin interior assembly includes a shell structure located within the airframe structure. The shell structure is formed from a plurality of axially spaced bell frames. Each bell frame is unitary and extends from one side of the cabin interior, across the ceiling and down to the other side. At least two longitudinal support members are attached to and extend between each adjacent pair of the bell frames. A plurality of panels are mounted to the shell structure with the edges of adjacent panels forming a butt joint as they overlap the bell frames and longitudinal support members. Isolators are disposed between the shell structure and the airframe structure. Each isolator includes a first component mounted to a lower end of a bell frame and a second component mounted on the airframe structure.

Abstract: An integrated fire and flight control system of the type which controls aircraft flight dynamics to referenced values defined by a weapon launch solution to provide optimum aircraft to target orientation, further optimizes the aircraft's angle of attack (AOA) to the target by controlling the aircraft's vertical speed to modify the aircraft's rate of climb or descent as necessary to produce an actual pitch attitude that is within a range of AOA values corresponding to the range of permissive weapon launch vertical speeds recommended by the weapons manufacturer.

Abstract: A heat ejection device is disclosed for a heating system. The heat ejection device is adapted to mix ambient air from an interior with bleed air from a heat source. The heat ejection device includes a housing with an inner passage, an inlet and an outlet. The inlet is adapted to channel ambient air into the housing. The outlet is adapted to channel mixed heated and ambient air out of the housing. A dispenser is located in the housing between the housing inlet and outlet and includes an inner chamber which is adapted to receive heated air from a bleed line. The dispenser has a plurality of apertures formed in it which permit air to flow from the inner chamber into the inner passage for mixing with ambient air to form a flow of mixed air. An acoustically absorptive inlet liner is mounted on an inner surface of the housing at the housing inlet. The absorptive inlet liner is adapted to direct ambient air past the dispenser to minimize turbulence and absorb noise.

Abstract: An active noise control system for minimizing undesirable acoustic noise in a defined volume, wherein the undesirable acoustic noise is generated by high frequency structural vibrations emanating from a vibration source structurally coupled to the defined volume at a structural interface. The active noise control system comprises a sensor subsystem disposed in combination with the defined volume for sensing the undesirable acoustic noise in the defined volume, an actuator subsystem disposed proximal to the structural interface, and a controller functionally interconnecting the sensor subsystem to the actuator subsystem, the controller being operative to receive input from the sensor subsystem and to transmit command signals to the actuator subsystem in response thereto for generating selected high frequency counter-vibrations that are interactive with the high frequency structural vibrations to minimize the undesirable acoustic noise in the defined volume.

Abstract: A helicopter main rotor pylon support structure including a framing structure for supporting the loads applied to the main rotor pylon, and a fire shield for preventing fire from transmitting from an engine or exhaust compartment into an adjacent compartment. The framing structure includes first and second composite main beams, each beam extending adjacent to a engine compartment and an exhaust duct compartment. A plurality of bridge members preferably extend between and connect with the first and second main beams and are formed integral therewith. A plurality of vertical posts are attached to and spaced along the main beams. The vertical posts are engaged with discrete attachment points on the helicopter. There is at least one fire panel mounted to each main beam. The fire panel has side edges which are slidingly engaged with the vertical posts, and a lower edge which is slidingly engaged with a flange formed on the helicopter.

Abstract: A transfer device for picking up and placing resin preimpregnated composite plies. The transfer device includes a movable transfer head with a plurality of transfer feet movably mounted within it. Each transfer foot includes a support cage with a plurality of spaced posts extending between upper and lower ends. A mounting plate is located on the support cage. A pickup foot extends from the lower end of the support cage and has a channel formed through it which communicates with an opening in the lower end of the support cage. The pickup foot includes a tip end adapted to contact the resin preimpregnated composite ply. A valve is mounted within the support cage and includes a valve member located adjacent to the opening in the lower end of the support cage. The valve member is movable between a closed position and an open position. A spring surrounds at least a portion of the periphery of the transfer foot and biases the transfer foot into the transfer head.

Abstract: An IR Suppressor (20) operative to suppress the infrared signature radiated from the high-temperature exhaust of an engine (12) and comprising a primary exhaust manifold (22), first and second mixing ducts (24a, 24b), and a secondary flow shroud (26). More specifically, the primary exhaust manifold (22) includes an elongate duct (28) adapted for receiving a primary flow of the high-temperature engine exhaust from the engine and at least two high aspect ratio nozzles (30a, 30b) integrated in combination with the elongate duct (28). The high aspect ratio nozzles (30a, 30b) are positioned so as to define at least two outlets at the same axial station along the length of the elongate duct (28). The first and second mixing ducts (24a, 24b) are disposed over the high aspect ratio nozzles (30a, 30b) so as to form a mixer/ejector defining at least two ejector inlets (44).

Abstract: A helicopter, or other aircraft, cargo bin is sized and configured so as to closely match the size and configuration of a closed cargo hold in the aircraft. The cargo bin is provided with a cover that is formed from a flame-retardant fabric which can be folded forwardly to open the top of the cargo bin, whereby the open bin can be positioned on a hydraulic ramp in the cargo hold before or after the bin is filled with cargo. The bin also has a hinged back wall which can be partially folded downwardly so as to open the upper portion of the back wall while keeping the lower portion of the back wall closed. This allows luggage or the like to be placed in the bin, when the bin is in the cargo hold, through the upper open portion of the bin, while enabling the lower closed portion of the bin to prevent the inserted luggage from sliding out of the bin.

Abstract: An active noise control system for a helicopter for minimizing undesirable acoustic noise in a cabin defined by a cabin structure, wherein the undesirable acoustic noise is generated by high frequency structural vibrations emanating from a gearbox, and wherein the gearbox has a plurality of attachment feet structurally coupling the gearbox to the cabin structure at a plurality of structural interfaces.

Abstract: An aircraft autopilot system provides a wind correction angle which is added to the desired course to provide commanded heading, the wind correction angle being generated as a proportional and integral function of ground track error. When the aircraft is off its desired course, it can be returned to the desired course by means of a course intercept angle, added to the desired course, to provide a corrected commanded course, the course intercept angle being a proportional function of the perpendicular error (the lateral distance of the aircraft from the original course) suitably limited to some angle within 90.degree. of the desired course. The course correction angle may be generated as a proportion of the perpendicular course error determined by the degree of importance of accuracy, and may be switched over to a course directly toward a waypoint in dependence upon the importance of efficiency.

Abstract: A masking tool (60) for use in combination with a shaped-workpiece (30.sub.S) in the manufacture of a precision gear (10), which shaped workpiece (30.sub.S) defines a plurality of gear teeth (12) and tooth space surfaces (68) defined by and between adjacent gear teeth (12). The masking tool (60) is, furthermore, operative to mask the tooth space surfaces (68) during surface deposition of a masking material (28) while facilitating deposition of the masking material (28) upon the top lands (14) of the gear teeth (12). The masking tool includes a flexible back-plate (64) and a plurality of compliant masking segments (62) bonded to and integrated by the flexible back-plate (64). Each of the compliant masking segments (62) define a surface geometry (66) which is substantially complementary to the respective tooth space surface (68). Furthermore, adjacent compliant masking segments (62) define an open-ended channel (70) therebetween.

Abstract: A structural interlock (40) for inhibiting relative rotation between mating elements (20, 42) characterized by a plurality of grooves (50) being formed in one of the mating elements, and a mechanism (60) for producing a nominal contact pressure on the contact area (A.sub.1 thru A.sub.8) between the mating element, which contact pressure elastically deforms the other of the mating elements into the grooves (50), and is less than the material yield strength of either of the mating elements. In the preferred embodiment, the grooves (50) are radially oriented and an applied compressive load produces a nominal contact pressure which is about 80% of the material yield strength.

Abstract: A masking tool (60) for use in combination with a shaped-workpiece (30.sub.S) in the manufacture of a precision gear (10), which shaped workpiece (30.sub.S) defines a plurality of gear teeth (12) and tooth space surfaces (68) defined by and between adjacent gear teeth (12). The masking tool (60) is, furthermore, operative to mask the tooth space surfaces (68) during surface deposition of a masking material (28) while facilitating deposition of the masking material (28) upon the top lands (14) of the gear teeth (12). The masking tool includes a flexible back-plate (64) and a plurality of compliant masking segments (62) bonded to and integrated by the flexible back-plate (64). Each of the compliant masking segments (62) define a surface geometry (66) which is substantially complementary to the respective tooth space surface (68). Furthermore, adjacent compliant masking segments (62) define an open-ended channel (70) therebetween.

Abstract: In a rotary wing aircraft, longitudinal groundspeed error and lateral groundspeed error are converted to earth coordinates, and the result scaled and integrated, and retransformed into aircraft coordinates for application to a pitch attitude control system and a roll attitude control system. The invention thus instantly transfers wind trim between the longitudinal and lateral channels, whenever a heading change is undertaken.