Abstract: A boundary layer control device is installed in the acoustically treated inlet duct of a turbofan engine. The device sucks off the turbulent boundary layer of air flowing over the inner or "air wetted" surface of the inlet during aircraft take-off, cruise and approach. The lip of the inlet can thus be made thinner to reduce drag during cruise without degradation of fan performance during take-off. The acoustic liner of the inlet comprises a microporous honeycomb sandwich structure through which air may be sucked at various locations through headers and conduits connected to an onboard pump.

Abstract: A perforated flat ribbon heating element embedded or sandwiched between the porous material and perforated sheet of honeycomb acoustic panel material used for sound suppression and deicing on ice buildup areas of an aircraft engine.

Abstract: The disclosure relates to a method of joining titanium and titanium based alloys to columbium at low pressure and low temperature, wherein a titanium foil is electroplated with layers of copper and nickel with a columbium sheet then being placed in intimate contact with the exposed layer. The materials are then heated in a vacuum to a temperature above the Ti-Cu-Ni eutectic temperature and below the beta-transus of the titanium material to provide a joining of titanium to columbium without materially altering the mechanical properties of the materials involved.

Abstract: A pin assembly for removably attaching a jaw portion of a translatable jaw of a stretch jaw chuck through an elongated slotted opening in the chuck wall. A bushing is threaded into mating threads in a bore in the jaw portion. The bushing has a centrally positioned substantially rectangular shaped opening extending therethrough with a slot formed on the bottom exterior surface of the bushing adjacent to each elongated side of the rectangular opening therethrough. An attachment pin is provided with a first end configured to pass through the opening in the bushing and latch into the aligned slots on the outer surface. The pin has a coil spring confined between a pair of flat washers. The first washer adjacent the second end of the pin rides against a nut adjustable along a threaded portion of the pin.

Abstract: A method of producing an open, triaxial woven, acoustic face sheet useful in acoustic energy absorbing panels for aircraft engines or the like. The composite face sheet is formed from carbon fibers in an epoxy resin matrix and has about 25 to 33% open area. This face sheet has lower weight and superior and more uniform strength and stiffness than biaxial composite face sheets. The face sheet is made by first weaving carbon fiber tows at warp angles of +30.degree. and -30.degree. and a fill angle of 90.degree.. The woven sheet is impregnated with epoxy as other resins in a manner which produces no rich or starved areas and no blocked openings. The resulting prepreg material may be stored for extended periods at reduced temperatures. The prepreg material is shaped on a suitable mold surface and the resin is fully cured, preferably in a vacuum bag assembly in an autoclave. The resulting sheet has very light weight, an excellent percentage of openings and high strength and stiffness.

Abstract: A honeycomb core manufacturing machine which includes a mainframe assembly and a transport assembly carried by and translatable along the mainframe assembly. The mainframe assembly comprises vertical and horizontal translatable upper and lower weld electrode assemblies. The transport assembly comprises upper and lower weld wheel electrode assemblies, an upper and lower weld electrode spreader assembly and a corrugated ribbon strip placement mechanism for placing ribbon between the spread apart upper and lower negative weld electrode assemblies with crest and trough of adjacent layers in registry.

Abstract: A hold open rod for holding open a hinged section of a nacelle system for maintenance. The rod includes a tubular member connected to the hinged section and a rod which telescopes within the tubular member and which is connected to the engine contained within the nacelle system. The hold open rod is provided with a novel locking feature which permits telescoping of the rod member within the tubular member only when the hinged section is opened further to permit manual disengagement of a latch member locking the rod member within the tubular member.

Abstract: A thrust reversing system for controlling the fan gases from a thrust producing aircraft engine. The system comprises a first group of blocker doors surrounding the upper longitudinal portion of the engine fan duct; a second group of blocker doors positioned rearward of the first group surrounding the entire engine fan duct; mechanism is provided for translating an upper movable fairing and a lower sleeve section which during translating provides an upwardly directed opening from the fan duct through gas-directing cascades and deploys the blocker doors from a stowed duct wall lining position to a deployed fan gas blocking deployed position.

Abstract: A noise suppression panel having a first cellular core positioned between and bonded to an imperforate facing sheet on one surface thereof and a first sheet of microporous material on the other surface. A second core is bonded between the other surface of the first sheet of microporous material and a perforated sheet. The other surface of the perforated sheet has a second sheet of microporous material bonded thereto. The cells of the two cores are preferably substantially aligned when maximum core-to-core bonding strength therebetween is required. A method of manufacturing is disclosed which includes flow-through resistance testing of the subassemblies.

Abstract: Broad band noise attenuation sandwich panels utilizing a cellular core positioned between and bonded to two facing sheets by an adhesive bonding system. One facing sheet is perforated and the other imperforate. A thin sheet of porous fibrous felt or fabric is bonded to the outer surface of the perforate sheet. The adhesive layer, at least between the perforate sheet and the porous fibrous material, is sufficiently thick to isolate the two components and form a funnel shaped opening necked down at the entrance to each perforation.

Abstract: Method of manufacturing broad band attenuation panel structure and the resulting structure therefrom for utilization in high temperature applications, having a maximum temperature in the range of 1600.degree. F. The panel comprises a cellular core constructed of Inconel, titanium alloys, 321 stainless steel, P H hardened stainless steel and the like, positioned between and brazed, liquid interface diffusion (LID) bonded, or diffusion bonded to two facing sheets, one imperforate and one perforated, the facing sheets constructed of a similar material. A sheet of porous metal overlay made of Inconel, nickel, monel, stainless steel alloys or the like is diffusion bonded to the outer surface of the perforated facing sheet.The sequential steps of sizing, cleaning, plating, and heating are set forth as well as the details of pressure, temperature, and protective atmosphere, and protective materials.

Abstract: Thrust reverser actuation mechanisms comprising a pair of nested screwjacks commonly driven by a screwjack drive motor. The inner screwjack translates the blocker doors aft and the outer screwjack deploys the blocker doors into the engine jet stream. The screwjacks have different thread pitches so that the blocker doors are translated aft at a faster rate of speed than they are deployed into the engine jet stream.

Abstract: A rotating die system for cold forming of sheet metal wherein a male die rotates relative to both an hydraulically supported resilient diaphragm backing the sheet metal blank and the driving force on the male die. The male die is pivotly connected to both a draw ring and the transmitted driving force. A sheet of metal to be formed is held in place on the upper surface of a draw ring die over a forming aperture. The male die is caused to rotate within the aperture against the sheet metal to accomplish the desired forming.

Abstract: In acoustic panels employing a layer of perforate metal adhesively bonded to a layer of porous fibrous metal of a different type with the perforations of the perforated layer and the pores of the porous fibrous layers open to communication therethrough and the layers being isolated therebetween. The isolation between the layers is maintained by applying a coating of liquid epoxy resin material to selected locations, curing the epoxy coating, cutting or drilling the layers as required, and recoating the cut or drilled areas with a second coating of liquid epoxy resin.

Abstract: A method of forming perforations in composite laminates by impregnating the material with a modified epoxy resin by means of hot melt or solvent methods. The resin is then allowed to dry. The epoxy impregnated material is then warmed to around 165.degree. F. and forced by a resilient pressure pad over a tool having a plurality of upstanding studs or pins. While in position on the pin tool, the laminate is then partially cured by combined heat and pressure to minimize resin flow while retaining the ability to be formed to a final contour in a contoured curing fixture after removal from the pin tool. Controlled partial cure and selected low flow resin systems prevent resin flow into the formed apertures formed by the pin tool during final resin cure.

Abstract: A method of brazing the nodes of honeycomb core material and the top and bottom panels to the honeycomb core material to form a sandwich structure. The method comprises the insertion in selected cells of the core, a coil or loop formed of normally flat resilient braze foil ribbon under tension and then releasing the tension to allow the braze foil, coil or loop to be urged against the cell walls under its own resiliency. The top and bottom panels are then installed over the core adjacent to the cell faying edges to form top and bottom surfaces. Pressure is then applied from the panels toward the honeycomb core material. The temperature of the sandwich structure is then elevated until the braze foil is caused to melt. Capillary attraction causes the now liquid braze material to flow into the interstices between the cell nodes and between the faying edges of the honeycomb core cells and the adjacent panels.

Abstract: In acoustic panels employing a layer of perforate metal adhesively bonded to a layer of porous fibrous metal of a different type with the perforations of the perforated layer and the pores of the porous fibrous layer open to communication therethrough and the layers being isolated therebetween. The isolation between the layers is maintained by applying a coating of liquid epoxy resin material to selected locations, curing the epoxy coating, cutting or drilling the layers as required, and recoating the cut or drilled areas with a second coating of liquid epoxy resin.

Abstract: A noise suppression panel having a first cellular core positioned between and bonded to an imperforate facing sheet on one surface thereof and a first sheet of microporous material on the other surface. A second core is bonded between the other surface of the first sheet of microporous material and a perforated sheet. The other surface of the perforated sheet has a second sheet of microporous material bonded thereto. The cells of the two cores are preferably substantially aligned when maximum core-to-core bonding strength therebetween is required. A method of manufacturing is disclosed which includes flow-through resistance testing of the subassemblies.

Abstract: A sandwich type acoustical absorbing panel for use adjacent to high speed gas flow areas in and around the engines of high speed aircraft. The panel in one embodiment comprises an imperforate facing sheet including having upright side and end walls, the inner volume of the panel and upright side and end walls are divided by means of partitions into a plurality of individual cavities or cells, each of the plurality of individual cavities or cells are filled with a bulk absorber material having many small torturous air passages, such as, open celled foam, fiberglass, felts or the like, the bulk absorber filling each cavity or cell is encapsulated in a membrane of thin limp material for preventing bulk absorber contamination and a perforated sheet overlay for attaching to the side, end walls and partitions for containing the bulk absorber within the cavities or cells.

Abstract: A process for selectively electroplating the nodes of dimpled titanium material. A sheet of clean dimpled titanium material is placed on a electrolyte saturated absorbent fabric covered block of conductive material. A flat sheet of metal, such as, stainless steel is placed on the opposite surface of the dimpled sheet to provide dead weight to hold only the nodes of the dimpled sheet in contact the absorbent material the dimpled sheet serving as one electrode for the electroplating process. The conductive block being the other electrode. Current is then passed through the electrolyte solution between the electrodes causing only the nodes to become plated. The electrolyte may contain, for example, copper or nickel in solution. A plating mask in the form of a frame may be placed between the flat sheet of metal and the dimpled sheet to provide uniform plating of the node surfaces.