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: 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: A video display system for a mobile simulator, comprising a shock-isolated projector assembly for projecting video images, a shock-isolated first mirror assembly disposed in combination with the projector assembly, a shock-isolated second mirror assembly disposed in combination with the first mirror assembly, and a shock-isolated screen assembly disposed in combination with the second mirror assembly, wherein the projector assembly, the first mirror assembly, the second mirror assembly, and the screen assembly are configured, in combination, such that the video images projected by the projector assembly are directed to the first mirror assembly, are reflected from the first mirror assembly to the second mirror assembly, and are subsequently reflected from the second mirror assembly onto the screen assembly.

Abstract: A method and apparatus for controlling lateral vibration in a rotating shaft, wherein the lateral vibration is controlled through the disposition of a mass having a predetermined weight in combination with the rotating shaft such that the first order critical frequency of the shaft is decreased below an operating frequency range for the rotating shaft. The mass is disposed in combination with the shaft at a second order critical frequency node such that the disposition of the mass does not decrease the second order critical frequency.

Abstract: A system and method for automatically controlling cabin air temperature T.sub.CBN in an aircraft having a cabin and a mixed air delivery system. The mixed air delivery system provides a flow of mixed air having an actual mixed air temperature into the cabin. The mixed air delivery system comprises a hot bleed air sub-system for providing a flow of hot bleed air, a cool air sub-system for providing a flow of cool air, and an ambient air sub-system for providing a flow of ambient air. The method comprises the steps of defining a selected cabin air temperature T.sub.CBN SEL, and then controlling the flow of hot bleed air, the flow of cool air, and the flow of ambient air such that the mixed air temperature is driven toward a target mixed air temperature defined as k(T.sub.CBN SEL -T.sub.CBN)+T.sub.CBN SEL, wherein k is a gain factor.

Abstract: A spring-mass vibration absorber for absorbing vibration in a structure. The vibration absorber comprising a baseplate having a first surface and a second surface, and a plurality of recurved springs connecting the baseplate to the structure. Each of the recurved springs is fixedly connected to the first surface of the baseplate at a baseplate connection point, and fixedly connected to the structure at a structure connection point.

Abstract: A mobile modular simulator system comprising a mobile base, a multimedia subsystem module demountably coupled with the mobile base, and a controller subsystem module demountably coupled with the mobile base, wherein the controller subsystem is configured for electronic coupling with the multimedia subsystem module for receiving input therefrom and for delivering output thereto to simulate an operating environment.

Abstract: An apparatus for installing a leading-edge sheath onto a helicopter main rotor blade subassembly, including a lower assembly having a leading-edge sheath contour nest configured for supporting the leading-edge sheath, opposed carriage members connected to a base, wherein each of the opposed carriage members supports a plurality of suction cups and is capable of synchronized translational movement relative to the leading-edge sheath contour nest between an engaged position wherein the plurality of suction cups are in abutting engagement with the leading-edge sheath, and a disengaged position where the plurality of suction cups are disengaged from the leading-edge sheath.

Abstract: A helicopter rotor brake assembly for arresting rotational movement of a main rotor drive shaft, wherein the helicopter rotor brake assembly is mechanically interconnected with the main rotor drive shaft through a main transmission. The helicopter rotor brake assembly includes a brake disc rotatably mounted about an axis, wherein the brake disc is mechanically interconnected with the main transmission, and wherein the brake disc defines a plane substantially perpendicular to the axis. A bracket is provided for disposal in combination with the brake disc, and comprises a beam member defining a first end and a second end, a first arcuate member connected to the first end of the beam member and disposed substantially co-planar with the plane defined by the brake disc, and a second arcuate member connected to the second end of the beam member and disposed substantially co-planar with the plane defined by the brake disc.

Abstract: An apparatus for assembling a helicopter main rotor blade subassembly which includes a lower airfoil skin, a core, an upper airfoil skin, and a spar assembly having a tip end and a root end, the apparatus including a lower assembly including a base having a contoured upper airfoil nest, wherein the contoured upper airfoil nest has a root end and a tip end, at least two guide ramps disposed proximal to the contoured upper airfoil nest, wherein at least one of the guide ramps is disposed proximal to the root end and at least one of the guide ramps is disposed proximal to the tip end, and a plurality of leading-edge pusher cams disposed proximal to the contoured upper airfoil nest.

Abstract: A method for fabricating a helicopter blade subassembly includes the steps of providing a blade compaction apparatus having a lower assembly configured for mating with an upper assembly. The lower assembly includes a base having a contoured upper airfoil nest with at least two guide ramps and a plurality of leading-edge pusher cams disposed proximal thereto. The upper assembly includes a support structure supporting a flexible impervious membrane, wherein the flexible impervious membrane and the contoured upper airfoil nest define a molding cavity therebetween upon mating of the upper assembly to the lower assembly. The method further includes disposing the upper airfoil skin and the core in combination with the contoured upper airfoil nest, and then connecting a tip end support insert and a root end support insert in combination with the spar assembly, wherein each of the support inserts include guide members.

Abstract: A drive shaft casing for a ducted fan anti-torque device for reducing the radar signature of the drive shaft, while concurrently having a minimal impact on the drive shaft's acoustic signature. The casing is formed from radar absorbing material and is disposed about the drive shaft such that the drive shaft casing comprises an inboard region spaced proximal to the hub and defining a thickness profile relative to a high speed flow of air provided by the fan assembly, and an outboard region spaced proximal to the inner surface of the airflow duct and defining a thickness profile relative to the high speed flow of air, wherein the thickness profile for the outboard region is less than the thickness profile for the inboard region.