Abstract: A flight simulator includes a central processing unit and a flight simulation environment controlled by the central processing unit for simulating the flight of an aircraft. The central processing unit is programmed to observe a full fidelity model of the aircraft in flight so as to extract pilot inputs and aircraft responses at each of successive time intervals. The central processing unit is further programmed to calculate a damping and an undamped natural frequency of the aircraft from the extracted pilot inputs and aircraft responses and to simulate the flight of the aircraft by applying the damping and undamped natural frequency to a second order transfer function.

Abstract: A dual frequency laser amplifier includes a beam generator for generating first and second source laser beams, and a co-doped optical fiber including first and second dopant ions having first and second gain bandwidths corresponding to the respective wavelengths of the first and second source laser beams for selectively forming first and second diffraction limited output laser beams responsive to the relative radiated power between the first and second source laser beams. A dual frequency laser oscillator and a method for generating the first and second output laser beams at any predetermined radiated power distribution are also described.

Abstract: A more resistive, low loss magnetic alloy containing at least 80% cobalt, at least 10 wt % iron, about 2.5 wt % nickel, and about 0.3-2 wt % impurities including boron and manganese. The alloy is well suited for deposition upon dielectric substrates such as polyimide or polyester tape by electroless deposition processes and allows for greater film thickness in a single layer and that has lower loss than other alloys presently available for such uses.

Abstract: A current-driven signal conditioning system comprising a first terminal, a second terminal, a strain gauge, and an instrumentation amplifier is disclosed. The strain gauge is adapted to measure a deformation of a structure and to generate a resistance which corresponds to the measured deformation. The instrumentation amplifier is adapted to be connected between the first terminal and the second terminal. The instrumentation amplifier is further adapted to be connected to the strain gauge and to place an output current on the second terminal. The output current is proportional to the resistance generated by the strain gauge. An output resister is coupled between the strain gauge and the second terminal, and a capacitor is coupled between the resister and the first terminal. A zenor diode is coupled between the first terminal and the strain gauge, and a diode is also coupled between the first terminal and the strain gauge.

Abstract: A method for embedding piezoelectric ceramic transducers in thermoplastic composites. The piezoelectric ceramic transducer to be embedded in a graphite/PEEK composite is first bonded with two fine silver wires for electrical connection, one on each major surface. The bonding agent is a high temperature conductive adhesive compound, such as a silver/glass frit. The fusing of the frit bonding agent is done in an over at a high temperature (i.e. 600.degree. F. or higher) for 5 to 10 minutes. Bonds are applied at several discrete spots on the zig zag wire which relieves thermal stresses induced during cooling due to a mismatch of the coefficient of thermal expansion between the ceramic material and the wire. After the connecting wires are attached, the wires and transducer are wrapped with several plies of insulating glass/PEEK cloth to prevent electrical shorting between the two silver wires through the graphite/PEEK host.

Abstract: The machined-sandwich structural assembly has two components joined together with a joint of substantially the same strength as the weakest base material. More specifically, the structural assembly includes a first structural member and a second structural member. The first structural member is spaced from the second structural member through a plurality of intermediate members which extend between the first structural member and the second structural member. The plurality of intermediate members are friction stir welded to the first structural member. The resultant assembly requires less stock material, takes less time to machine and has a joint of improved strength.

Abstract: The present invention provides a friction stir welding device for optimizing the depth of a friction stir welding tool in a workpiece. The welding device includes a spindle and a welding tool in rotatable communication with the spindle. The welding device also includes an inner housing defining an aperture through which the welding tool at least partially extends. Preferably, the inner housing has a plurality of cam followers. The device also includes an outer housing defining an aperture for at least partially receiving the inner housing. The outer housing has a base member and a riser that is rotatably mounted to the base member and that defines a plurality of inclined surfaces upon which the plurality of cam followers ride. The welding device includes a sensor in electrical communication with a controller for measuring the magnitude of force exerted by the welding tool upon the workpiece.

Abstract: Reinforcing members for securement of reinforced plastic composite components in restricted and confined space locations as a substitute for reinforcing stitching. The reinforcing members are highly effective for securing "T" stiffeners and the like to a skin structure in confined and restricted locations where a stitching machine cannot be used. The composite pieces which are reinforced and secured together by the reinforcing members provide excellent damage tolerance, are highly resistant to delamination and are resistant to tensile pulling and plane shear properties. The reinforcing members primarily comprise a plurality of pins or spikes which are effectively formed by sewing through a disposable and eliminatable core such that when the core is removed, all of the pins, which originally constituted threads passing through the core are secured together in an array by an open mesh physical cross-linking of the pins.

Abstract: An elastic ground plane (50) has an environmental coating (58) attached to a surface of a fabric (54) having a lo plurality of fibers. A conductive substance (56) is applied to the fabric (54) to coat the fabric (54).

Abstract: An air cargo container includes a relatively-rigid housing defining an air-tight interior space of nominal volume within which to receive cargo. The housing substantially maintains the nominal volume of the interior space upon pressurizing or evacuating the interior space relative to ambient pressure, whereby a differential interior pressure is achieved before loading the container aboard an aircraft. Where the differential interior pressure is achieved by pressurizing the interior space, air or another suitable gas is injected under pressure into the housing. Where the differential interior pressure is obtained by evacuating the housing's interior space, or where the process of pressurizing the interior space includes a prior evacuation step, the gases drawn from within the housing are preferably analyzed to detect the presence of contraband within the received cargo. Sensors on the housing confirm that an achieved interior pressure is substantially maintained over time.

Abstract: A zone of corrosion-resistant material covering a friction stir welded joint surface is provided by applying a layer of corrosion-resistant material over one or both surfaces of the workpieces being joined so that the layer covers at least the weld zone which will be rendered plastic during a friction stir welding operation. The corrosion-resistant material layer is contacted by the friction stir welding tool, and the tool causes shearing and plastic flow of the corrosion-resistant material along the surface of the welded joint. The corrosion-resistant material thus metallurgically bonds with portions of the plasticized metal so as to form a corrosion-resistant zone protecting the welded joint from exposure to corrosive environments.

Abstract: A method for chromium plating a part made of titanium or titanium alloy eliminates the conventional chemical cleaning of the part prior to electroplating, and instead employs a mechanical cleaning of the part including degreasing the part and then grit-blasting the part with aluminum oxide particles. Immediately following the grit-blasting step, for example within one minute of its completion, the part is connected to the negative terminal of a DC power supply and is then immersed into a bath of chromium plating solution which contains an anode element connected to the positive terminal of the power supply. The part is left in the bath for a period of time so as to deposit a plating of chromium on the surface of the part. For final finishing of the part, a post-plating grinding operation is performed in which the surface speed of the grinding wheel is not greater than about 6500 surface feet per minute and the in-feed rate is less than about 0.

Abstract: A cargo restraint includes a support, a housing which is rotatable relative to the support about a first rotation axis, and a plunger which is slidable within the housing along a second axis normal to the first axis, the plunger having a portion serving as a restraint for cargo. A torsion spring connects the housing to the support such that the housing is automatically rotatably urged into a predetermined deployed or cargo-engaging position, and a compression spring automatically urges the plunger into an extended cargo-engaging position. The restraint is thus self-deploying, and can resiliently yield to both direct and indirect impacts.

Abstract: An improved jet thruster system for use in a helicopter without a tail rotor. A non-rotating outer thruster assembly is attached to the rear of the tail boom which, within it, has a source of low pressure air. The outer thruster assembly has a window on each side. Nested within the outer thruster assembly is an inner thruster assembly with a single window which rotates within the outer thruster assembly in response to commands from the helicopter control system. As the single window in the inner assembly is rotated around to where it overlaps with one or the other of the side windows in the outer assembly, an exit opening is created for the low pressure air which in turn creates a desired side force on the tail boom to counteract the torque created by the main rotor and also to provide yaw control for the helicopter. The interior of the inner thruster assembly contains vanes and an air ramp to efficiently redirect the air flow from axial flow to lateral flow within the inner thruster assembly.

Abstract: The stores ejection system of the present invention includes a single release hook and swaybraced ejection rams for releasably mounting and forcibly ejecting miniature munitions and other miniature stores on an aircraft. The pneumatically-driven stores ejection system can accommodate miniature stores having bail lugs sized to reduce store aerodynamic drag and radar signature and to improve store delivery accuracy.

Abstract: A method and apparatus for reducing noise across a broadband frequency range transmitted by a vibrating panel by blocking or otherwise opposing increasing non-resonant modes of vibration in the panel. The method and apparatus includes mounting an array of sensors on a surface of the vibrating panel. The sensors generate an input signal representing the incident vibration in the panel. The input signal is sent to an adaptive controller which generates an output signal. The output signal is essentially equivalent to the input signal but opposing in phase. The output signal is then sent and distributed to an array of actuators which are also mounted to a surface of the vibrating panel. The output signal forces each of the vibrating actuators to vibrate the panel in opposition to the incident vibration in the panel and thus reduce the transmitted noise. Continual readings of the vibration in the panel allows the sensors to update the input signal and thus adjust the vibration of the actuators.

Abstract: The frequency measurement method and associated apparatus accurately determines the frequency of a periodic signal even if the frequency exceeds the nyquist frequency, typically established by the analog to digital ("A/D") converter used to sample the signal. The frequency measurement method and apparatus obtains samples of a periodic signal at a number of sample rates, converts the samples to the frequency domain, analyzes the first order alias frequencies produced due to undersampling of the signal, and determines the frequency of the periodic signal based upon the alias frequencies. In selecting the sampling rate and the first order alias frequencies, the frequency measurement method and apparatus accounts for sampling errors, frequency calculation errors, desired frequency ranges, and measurement precision. Through error compensation and minimization techniques, the frequency measurement method and apparatus reduces the number of electrical components required (e.g. A/D converters).

Abstract: A phase locked distributed time reference system for use in multiplexed communication bus structures. This system is composed of two parts, a master and a slave time reference or clock. The master time reference is a high accuracy clock that is a dedicated distributed clock system which uses an appropriate communication bus, such as the MIL-STD-1553, for distribution but which completely bypasses the other bus protocols and operations. This master time reference would ideally be placed on the processor bus for immediate access. The high order segment, which extend the master time reference to the desired range, i.e. 30 days or longer, is transmitted via the normal bus communications without the need for any special data handling. The only requirement is to update the signal at a cyclic rate faster than the roll over time of the low order segment plus any delay in transmission and assembly of the two halves.

Abstract: A vertical stabilizer fin and rudder assembly for use on an aircraft including a stabilizer fin with airfoil surfaces and a rudder with a forward margin pivotally mounted on the trailing edge of the stabilizer fin. The assembly is subjected to Bernoulli forces as a relatively moving airstream passes over it in a chordal direction. A fin spoiler is pivotally mounted on each fin surface at a forward chordal location on the assembly whereby the effective sideslip capability for the fin surfaces, when the aircraft is operated in a crosswind, is substantially increased.

Abstract: A stand alone terrain conflict detector of an aircraft includes a global positioning system (GPS) receiver, an inertial navigation system, navigational and topographical databases, a control panel, a central processing unit (CPU), which CPU generates position data, a current flight path vector and control signals, an obstacle detector which receives the position data and the current flight path vector and which generates a flight path signal, an alert signal identifying a terrain threat to the aircraft and a projected flight path vector, a video generator coupled to the obstacle detector and the CPU, and a display connected to the video generator. The display outputs one of a 2D image, a first 3D image and a second 3D image and the terrain threat generated by video generator.