Abstract: The torque limiter described herein is a device for preventing the transmission of torque from a drive source to a torque responsive element when a predetermined torque limit has been reached. The device also provides subsequent mechanical indication that the predetermined torque limit has been reached. The device operates by transmitting torque between two axial members, a drive member and a driven member, having a plurality of balls therebetween with the balls engaged within precisely shaped sockets contained within each axial member. As excess torque occurs, the plurality of balls cause the driven member to axially displace with respect to the drive member, engaging a set of teeth contained on the driven member with a second set of teeth aligned with the first set of teeth and restrained within the housing, thereby preventing torque transmission.

Abstract: A modular approach to the manufacture of high performance military aircraft allows different aircraft to be manufactured at affordable cost and with high part number commonality. An aircraft so constructed includes a delta wing; a forebody section, including a cockpit, which is mounted to the front of the wing; and a propulsion system support frame mounted beneath the forebody section and the underside of the wing. The propulsion system is supported within this frame. The aircraft can also include an aftbody section mounted to the aft end of the wing, which includes a 2-D variable thrust vectoring nozzle and a pair of canted vertical tails. The forebody section includes a chin inlet below the cockpit. The wing is preferably constructed using thermoplastic welding.

Abstract: A passenger seat for reducing head impact in sudden impact events in an aircraft includes a panel for absorbing head impact. The panel is detachably fastened to the rear surface of a seat back so that the seat back will break free of the panel and be thrown forward while the panel will remain in an upright position. The panel is preferably made of a low mass material to absorb momentum of the head of a passenger seated behind it. The panel can be fashioned as a "dummy" seat back, detachably fastened to a seat back by hook and loop fasteners. It can be fabricated to aesthetically blend with the styling of the seat back.

Abstract: A method for fabricating a model includes the steps of stacking successive layers of aluminium honeycomb core to a desired height to form a block, machining the block to within a desired tolerance of the desired final contour, applying a layer of modeling material such as syntactic epoxy to the outer surface of the block, and machining the layer of modeling material to the desired contour. The result is a model from which a mold or composite parts can be fabricated, using high temperature and pressure processes if desired.

Abstract: A vertically launchable and recoverable winged aircraft includes an airframe, a least one proprotor connected to the airframe through a rotatable drive shaft, and collective and cyclic pitch control systems. The airframe includes a wing having a leading edge and a trailing edge which define a forward direction of flight in an airplane mode. The proprotors each have an axis of rotation generally parallel to the forward direction of flight in airplane mode, and include at least two proprotor blades. The cyclic pitch control system is operably connected to each blade to control the pitch of each blade, so that the aircraft is capable of controlled helicopter mode flight when the wing leading edge is pointed in a generally upward direction.

Abstract: The invention provides a unique approach to solving a peck feeding problem in limited access areas restricting the drilling unit size. It uses a power transmission system which is comprised of a pinion gear driven by a motor source. The pinion gear drives a bevel gear that is free to travel along a polygon quill. A quill had is located on one end of the quill to house the drill. The opposing quill end is attached to a guide bushing assembly. The guide bushing assembly is connected to a bell crank mechanism that is actuated and controlled by a pneumatic piston and hydraulic speed control system. The power transmission system, and the pneumatic power transfer system combined produce a pecking cycle for drilling precision holes within a confined set-up space of 5.5 inches in a preferred embodiment. It preferably has a drill stroke up to 1 inch deep, and is capable of producing a "pecking" action which is unique for right angle drilling equipment in limited access applications.

Abstract: A photonic device for controlling phased array beam direction includes an electro-optic substrate; a plurality of waveguides formed in the substrate, each of which is capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of the plurality of waveguides a pair of copropagating polarized light signals having orthogonal polarizations and different frequencies; a plurality of electrodes on the substrate configured to phase shift the signals traveling through each waveguide by a different amount in response to applied voltages, thereby creating phase shifted polarized signals; and means for combining the phase shifted polarized signals within each one of the waveguides and propagating these combined signal to an antenna element. The basic operating principle of the invention is based on the differential phase shift between optical waves of orthogonal polarizations traveling in an electro-optic optical waveguide.

Abstract: An optical switching network includes one or more planar substrates with an optical waveguide switching array formed thereon butt-coupled to a waveguide component. The waveguide component is a planar substrate with a plurality of passive optical waveguides thereon. The input ends and output ends of the waveguides are disposed along the butt-coupled edge(s) of the waveguide component substrate. The waveguides and switches are arranged with the waveguides interconnecting the input and output switch arrays so that an incoming optical signal can be directed to any desired output on the output array. The use of planar substrates with electro-optic and passive waveguide circuits allows for a modular approach, where the active switch array substrate and the passive waveguide substrates can be optimized individually. An N.times.N switch array circuit can be formed of N sets of N.times.1 switch arrays on the input substrate and N sets of N.times.1 switch arrays on the output substrate.

Abstract: A method for fabricating a model includes the steps of stacking successive layers of aluminum honeycomb core to a desired height to form a block, machining the block to within a desired tolerance of the desired final contour, applying a layer of modeling material such as syntactic epoxy to the outer surface of the block, and machining the layer of modeling material to the desired contour. The result is a model from which a mold or composite parts can be fabricated, using high temperature and pressure processes if desired.

Abstract: An optoelectronic package includes an optical fiber cable assembly and feedthrough assembly which provide high performance and high reliability optical fiber alignment, locking and sealing. An optical fiber is fed through a nose tube into the package. The fiber is selectively metallized at its end. A solder lock joint on a substrate on the package floor preferably of an SnAg- based or SnSb- based solder. It surrounds at least part of the metallized portion of the fiber so as to hold the fiber in its desired position, in alignment with an optoelectronic device in the package. With Sn metallization on the fiber, this results in a highly reliable solder lock joint. A solder seal joint forms a hermetic seal between the nose tube and the Au metallized fiber. This solder is preferably 80Au20Sn. A rigid cylindrical seal tube sleeve insert on the fiber is designed to guide the fiber into the nose tube without bending or damaging the fiber.

Abstract: An optical sensor system uses a light source which outputs light at a plurality of wavelengths which vary with time in a manner such that only one wavelength is output at any one point in time; and a transducer which modulates light at each wavelength in a manner indicative of the parameter (for example, position or temperature) begin sensed. The transducer's output is, therefore, an optical signal in which the modulated intensity varies with time since only one wavelength is output at any one point in time. Because only a single wavelength is output at any one time, there is no need for an optical demultiplexer and detector array. Only a single detector is needed.

Abstract: A method for selectively altering the refractive index of selected portions of a polyimide material can be used to form a variety of optical components, such as waveguides that can be used as optical interconnections between elements in electronic or microelectronic circuits. The method includes the steps of introducing a dopant which is capable of altering the index of refraction of the film and which will be photoattached to the polyimide material after exposure to radiation, exposing selected portions of the material to radiation, removing at least some of the dopant from the non-irradiated portions of the material, and then exposing the non-irradiated portions of the material to radiation of a type and quantity sufficient to alter the index of refraction of the material.

Abstract: The invention performs coordinate measurement employing multiple-frequency intensity-modulated laser radar. A laser diode source is intensity modulated by variation of its excitation current. Its output beam is directed to a target using scanning mirrors or other opto-mechanical means, and the light returned from the target is detected. The modulation frequency is alternated between two or more values, creating a dataset of several relative phase measurements that uniquely determine the distance to the target without ambiguity.

Abstract: A photonic device for controlling phased array beam direction includes an electro-optic substrate; a plurality of waveguides formed in the substrate, each of which is capable of simultaneously propagating light signals with orthogonal polarizations; an input waveguide for inputting into each one of the plurality of waveguides a pair of copropagating polarized light signals having orthogonal polarizations and different frequencies; a plurality of electrodes on the substrate configured to phase shift the signals traveling through each waveguide by a different amount in response to a common applied voltage, thereby creating phase shifted polarized signals; and means for combining the phase shifted polarized signals within each one of the waveguides and propagating these combined signal to an antenna element. The basic operating principle of the invention is based on the differential phase shift between optical waves of orthogonal polarizations traveling in an electro-optic optical waveguide.

Abstract: The invention provides a way to improve the voltage stand-off characteristics of photoconductors, including both surface and bulk photoconductors. In a preferred embodiment, the invention comprises a photoconductor device having a semiconductor substrate with electrodes thereon, and a light source which illuminates the surface of the device in a pattern which is configured to increase the stand-off voltage of the device. A method according to the invention includes the steps of directing light onto the surface of the photoconductor thereby forming an illuminated area thereon, measuring the current draw of the photoconductor, and moving the illuminated area along the surface of the photoconductor until the current draw is minimized.

Abstract: The frequency separation between two light signals, one having a first and the other having a second frequency, is determined by first forming three light beams, each including both frequencies; directing the three beams through an interferometer in which they traverse three optical paths having three different known optical path lengths; determining the interferometric phases for each of the three optical paths at both frequencies; and determining the difference between the first and second frequencies from the interferometric phases and known optical path lengths. The light signals may be light from two lasers operating at different frequencies. The optical path lengths can be predetermined by calibration using two light sources of know frequencies. An apparatus for carrying out this method is also disclosed.

Abstract: Radiation detectors are mounted in an optic focal plane of an infrared radiation sensor system. The radiation detectors produce output signals indicating detected radiation. The output signals are sampled by a sample-and-hold circuit and passed to a 1-bit comparator. The comparator produces a 1-bit signal at a high voltage level for samples of the output signal that are greater than a reference voltage and at a low voltage level for samples of the output signal that are less than the reference voltage. In this manner, the comparator reduces the effects of any gamma spikes on the measurement of intensity of radiation. The 1-bit signal is less susceptible to effects of interference than analog signals in conventional systems and the 1-bit comparator produces this 1-bit signal without consuming a great deal of electrical power. A multiplexor carries such 1-bit signals from the focal plane to a processor over less wires than in conventional systems.

Abstract: An optical time delay device includes a switching component butt-coupled to one or two delay line components. The switching component is a planar substrate with an optical waveguide switching array formed thereon. The delay line component is a second planar substrate with a plurality of optical waveguides of different optical lengths. The input ends and output ends of the waveguides are disposed along the butt-coupled edge of the second substrate. The waveguides and switches are arranged so that the switches direct an incoming optical signal to a selected one or more of said waveguides. In a preferred embodiment, one of the waveguides has an optical length .DELTA.L, and the remaining waveguides have optical lengths which are multiples of .DELTA.L. The use of planar substrates with electro-optic and passive waveguide circuits allows for a modular approach, with interchangeable delay line components chosen for a particular application and butt-coupled to the switching component.

Abstract: A microwave transceiver using a reflection pumped mixer includes an electromagnetic signal generator, a subreflector, a reflector of electromagnetic signals from the subreflector, a mixer, circulator, and processing circuitry to relate electromagnetic signal frequency differences to the range of a target from the transceiver. Such frequency differences are detected by the mixer from the captured electromagnetic signals reflected distant targets and reflected electromagnetic signals from the subreflector.