Abstract: An improvement is disclosed to the method of forming sandwich structures wherein a plurality of workpieces having opposed principal surfaces are placed in a stack contacting facing principal surfaces and thereafter diffusion bonding portions of said facing principal surfaces of said workpieces together and superplastic forming at least a portion of at least one of said workpieces. The improvement comprises coating at least one of the facing principal surfaces with a maskant. The maskant is then removed from the portions not to be diffusion bonded of the at least one coated facing principal surface. A stopoff material is applied to the portions where the maskant has been removed and thereafter the remaining maskant is removed. The preferred method of removing the maskant from the portion of the at least one coated principal surface comprises placing a template on the surface and thereafter cutting out the maskant.

Abstract: A liquid dye penetrant composition for use in non-destructive testing of objects to locate cracks and other defects or flaws therein, said composition comprising (1) a nonionic surfactant, such as an oxyalkylated aliphatic alcohol, (2) a small amount of a dye soluble in the surfactant and (3) a substantial and preferably a major proportion, of an N-alkyl-2-pyrrolidone, preferably N-methyl-2-pyrrolidone, as extender. Such composition is applied to the surface of an object containing cracks and other defects, water is applied to the surface of the object to remove excess liquid dye penetrant composition from the surface without removing such penetrant from such cracks and other defects, and with or without a developer, the surface of the object is viewed under suitable lighting conditions, e.g.

Abstract: A temperature control system is disclosed which supplies a fluid which acts as a temperature effecting agent for the system. The fluid is conveyed through the system with a temperature control means regulating the temperature of the fluid and a fluid control means regulating flow of the fluid through the system. The temperature control means includes a helix of electrically resistant tubing which the fluid passes through. Optimally, the helix is responsive to the application of electrical current such that temperature of the fluid passing through the helix is controlled as a function of the applied current. Preferably, a distribution network forms part of the system and uniformly distributes the fluid in a desired area and/or around an object. The fluid control means can also include a diverting means for diverting fluid not at a desired temperature from the system and an additional means to vary the temperature of the fluid distributed by the system.

Abstract: A method is disclosed for removing a part from a die, the part having been produced by clamping a preform between first and second dies and forming at least a portion of the preform into a cavity of the first die. The method comprises the steps of drawing a vacuum from between at least a portion of the formed preform and the second die and separating the second die from the first die such that the part is withdrawn from the cavity of the first die. In a preferred embodiment, wherein the part is clamped abouts its periphery, the method involves the additional steps of providing a channel about at least a portion of the second die aligned with and in communication with the periphery of the preform, and providing sealing members to seal off the channel. The vacuum is then drawn from the channel.

Abstract: A method for detecting cracks and surface discontinuities in an object which comprises applying to the surface of an object having a ground surface and smeared metal, an etchant penetrant solution capable of removing said smeared metal covering the openings of said cracks, cleaning said surface to remove said excess penetrant solution, and applying to said surface a developer coating containing a fluorescent material, the etchant remaining in the cracks being capable of destroying the fluorescence adjacent the cracks, and viewing the surface under ultraviolet light to reveal indications of cracks showing intensely black against a fluorescent background.

Abstract: This invention generally concerns an aircraft useful for training pilots, and specifically involves providing a trainer aircraft having high to moderate aspect ratio wings with selectively operable design features that impart to the trainer aircraft the handling characteristics of a high performance, swept wing aircraft in an approach and landing configuration. In particular, the high performance swept wing aircraft characteristics are preferably imparted by selectively actuated primary and secondary speed brake mechanisms. Optimally, the primary speed brake mechanism is positioned as a function of angle of attack of the aircraft.

Abstract: Substantially non-pollutant and non-toxic water washable composition in the form of a gel for use in non-destructive ultrasonic inspection of surface and subsurface flaws and discontinuities in bodies comprising a (1) poly(oxypropylene) poly(oxyethylene) condensate having a molecular weight ranging from about 1,000 to about 15,000, and (2) silica, particularly fumed silica, such silica being present in certain proportions, e.g. about 5% by weight of the composition. The composition or gel is applied to a surface of a body such as a metal aircraft structural part, and a probe or transducer of an ultrasonic testing device is contacted or pressed against the gel, and the transducer is caused to move or slide in various directions on the gel to transmit ultrasonic energy through the gel and the object, to inspect the object and locate any surface or subsurface flaws or discontinuities.

Abstract: A method of making sandwich structures from a plurality of workpieces is disclosed. The method comprises providing a plurality of workpieces, each having principal opposed surfaces. The workpieces comprise first and second outer workpieces and at least two core workpieces. Each of the core workpieces have cutout portions defining at least one strip. The workpieces are treated at selected locations to inhibit joining at said locations. The treated workpieces are positioned in a stack contacting at their principal surfaces. The workpieces are joined, preferably by diffusion bonding, at their untreated contacting surfaces such that alternate longitudinal edges of superimposed strips are joined together and to the outer workpieces. Preferably, at least one chamber is enclosed by positioning the stacked workpieces relative to a plurality of shaping members.

Abstract: Combination of a nonionic oxyalkylated alcohol surfactant and an engine fuel, e.g. a 50--50 mixture, by volume, of such surfactant and an aircraft engine fuel such as JP-4 jet fuel, consisting essentially of a mixture of gasoline and kerosene, which is miscible both with water-based and oil-based liquids, for removing water or water-based leak tracer solution entrapped in a fuel tank system, e.g. of an aircraft. When employing, for example, an aqueous leak tracer solution introduced into a fuel tank, e.g. of an aircraft, for locating any leaks therein, after inspection and removal of the main body of leak tracer solution from the tank, in order to remove any residual leak tracer solution which remains entrapped in the tank, the invention composition, hereinafter termed a "depuddling agent", is introduced and blends with the residual leak tracer solution, and the resulting miscible mixture is drained from the system.

Abstract: A method of fabricating a composite structure wherein a porous laminate comprised of a plurality of plies of fibrous material in an uncured resin matrix has entrapped air expelled. In carrying out the method, the laminate is positioned in an evacuable chamber. Vacuum is applied to the chamber to create a partial vacuum environment therein. The laminate is heated to within a temperature range wherein the resin matrix exhibits a viscosity which allows air migration through the resin matrix. The laminate is maintained within the temperature range for a time duration sufficient to expell entrapped air. The laminate can then be cured using vacuum to compress the laminate.

Abstract: A method is disclosed for fabricating rib structures of different sizes for a segment of an airfoil having both a spanwise taper in thickness and at least one aerodynamic surface having a substantially constant radius of curvature in the chordwise direction. In one embodiment a plurality of rib webs are formed at least as large as the largest rib structure. Each of the rib webs is trimmed at their lower edges progressively greater amounts to form rib webs of a proper size for each rib structure. A plurality of upper and lower rib caps as well as front and rear spar attachment brackets are formed and attached to the trimmed rib webs. In another embodiment the rib webs are formed with either or both integral upper rib caps and spar attachment brackets. In still another embodiment a plurality of rib webs are formed and joined together by twos by inverting one rib web to the other and progressively overlapping their lower edges and fastening them together to form properly sized rib structures.

Abstract: An aircraft having supersonic and subsonic flight capabilities which utilizes a variable dihedral angle tail unit to vary the aircraft geometry to improve aerodynamic efficiency, especially when changing from subsonic to supersonic speeds and vice versa, which saves propulsion energy and can be used to present minimal radar cross section from a given direction.

Abstract: A reinforced tubular structure comprising a metal tube and a cured composite tubular liner which increases the longitudinal stiffness of the tubular structure, the liner being adhesively bonded to the inner peripheral surface of the metal tube. The reinforced tubular structure is fabricated by forming a laminate of the composite material, wrapping it around a flexible mandrel, inserting the mandrel and wrapped laminate into the metal tube, and co-curing the laminate to the inner peripheral surface of the tube.

Abstract: A device is disclosed for inspecting whether the surface of a discrete portion of a part is within an allowable tolerance. The device comprises a base adapted to position the part for inspection. A probe is moveably mounted to the base and adapted to engage the surface. The probe, in one preferred embodiment, comprises a member slidably mounted on the base having an edge adapted to engage the surface. A mechanism is provided for limiting the movement of the member to the allowable tolerance of the contour of the surface, such that when the part is positioned for inspection the member will indicate whether the surface is within allowable tolerance if the edge of the member makes contact thereon.In another embodiment, the probe comprises a member slidably mounted to the base. A protractor, having an edge adapted to uniformly engage the surface, is mounted to the member and rotatable about an axis.

Abstract: A composite structure has two composite panels which are bonded together at a joint. The joint is reinforced by composite thread being sewn in a series of stitches through the panels. Sewing the panels while they are in a staged condition allows the structure to be co-cured as assembled.

Abstract: An improvement is disclosed to the method of making metallic structures from a plurality of stacked workpieces or blanks by joining first portions, preferably by diffusion bonding, of the stack and by clamping the joined stack at its periphery between forming members and superplastically forming second portions of said plurality of stacked blanks by the selective application of fluid under pressure. The improvement is a method of coupling the fluid to the second portions of the stack which comprises providing a first port through one of the outer blanks at the periphery of the stack. At least one stopoff path is provided for coupling the first port to the second portions of the stacked blanks, which are to be superplastically formed. A second port is provided in one of the forming members, which couples the first port to a source of pressurized fluid.

Abstract: An apparatus is disclosed for refueling an aircraft primarily fron a ship at sea, the ship being subject to changes in vertical and horizontal position due to pitch, roll, and heave, and combinations thereof. The apparatus comprises a first beam having a first end pivotally attached to the ship and extending upward therefrom. A second beam is pivotally attached at its first end to the second end of the first beam and extends substantially in a horizontal direction therefrom and preferably is supported by an air spring mounted between the first and second beams. A positioning device, preferably in the form of a hydraulic actuating cylinder, is coupled to both the first beam and the ship and is adapted to adjust the angular position of the first beam with respect to the ship in response to a first control signal.

Abstract: A radar false target elimination system for converting incident microwave electromagnetic energy to thermal energy to preclude reflection of radar energy which would otherwise induce the generation of a beacon response and a false target from an aircraft being tracked by the radar. The invention comprises a layered, sandwich configuration of materials, including an electrical component sheet having a coating of a combination of carbon and polymide resin in a selected ratio by weight on a low dielectric constant and loss tangent substrate and in a selected geometrical configuration to provide a lossy mixture for achieving the aforesaid energy conversion.The panel comprising such a sandwich configuration is mounted on potentially reflective structures in the vicinity of the radar which would otherwise permit reflections of radar energy along a false path to an aircraft.

Abstract: Leak tracer solution particularly effective for inspection of aircraft fuel tanks and lines prior to use, without staining painted surfaces of the aircraft consists essentially of an aqueous solution containing not more than about 10%, generally about 0.1 to about 10%, of a nonionic oxyalkylated aliphatic alcohol surfactant, and a small amount, generally about 0.005 to about 1.0%, of a water soluble, e.g. dual visibility, dye such as Uranine, which does not migrate into or penetrate the painted aircraft surface. A small amount of an anti-parasitic agent can be added to prevent algae growth. The solution is used by introducing it into the interior of new fuel tanks and lines, viewing the external surfaces of such tanks and lines under suitable lighting conditions such as daylight or black (fluorescent) light to detect any cracks or leaks, and draining the solution from the tanks and lines.

Abstract: An identification system for individuals which provides a three point identification check at point-of-transaction to assure accuracy is disclosed. The system utilizes an individual fingerprint and an identifier which can be correlated to the fingerprint and to a listing of valid identifiers. In carrying out the system, an identification card is used which has the individual's fingerprint, a grid superimposed over the fingerprint, and an identifier printed thereon. The identifier is made-up of a series of individual designations or symbols, with each individual designation representing a selected fingerprint characteristic in respective squares of the grid. A data bank for individuals in the system contains a listing of valid identifiers for correlation and validation purposes. The identifier may be made up of alpha, numeric, or alpha numeric designations.