Abstract: A method of making ducts having outwardly extending ribs formed integrally with the duct structure. Two tubes are formed from fiber reinforced resin materials, a uniform inner tube and a ribbed outer tube, then the inner tube is bonded with in the outer tube to form a high strength ribbed duct. An outer tube is formed by placing resin impregnated fibers over a cylindrical mandrel having an inflatable bladder on its surface, placing a plurality of spaced rings tightly against the outer surface, pressurizing the bladder to expand the tube into the spaces between rings to form low ribs, then gradually moving the rings toward each other to press the ribs therebetween and form thin upstanding ribs. The inner tube is formed by placing resin impregnated fibers on a slightly thinner mandrel that also has a surface bladder. When both tubes are formed, the mandrel is removed from the outer tube and the inner tube and mandrel are inserted therein and the inner tube bladder is inflated.

Abstract: A pivot door type aircraft turbine engine thrust reverser which includes a pair of pivoting panels on the inner side of the door. The panels are positioned alongside the door actuation mechanism. The panels form a flush surface along the fan duct flow path when stowed during normal engine operation in flight. When the door is deployed in thrust reversing mode, one end of the door moves to at least partially block airflow through the duct and divert it out along the door through an opening uncovered by door deployment. During door deployment, a linkage moves the panels toward the outer surface of the door, exposing a door deflector plate to the airflow. Air flows along the door, then along the panel, out through the opening, then impacts the deflector plate which deflects the airflow in the reverse direction.

Abstract: A locally reinforced honeycomb core panel having a honeycomb core, at least one coiled insert in at least one honeycomb cell and at least one face sheet. These components are formed from high temperature resistant metals. Elongated foil strips are coiled into cylindrical shapes having diameters slightly less than the width of individual cells in the honeycomb panel and heights no greater than the depth of the cells. These coiled inserts are placed in individual cells in selected portions of the honeycomb core to locally improve density, strength and thermal transfer characteristics of the panel. The coiled inserts have sufficient resiliency so that when they are inserted into cells and allowed to unwind, they press tightly against the cell inside wall even if the cell shape has been distorted in handling. The cells are held in place by the face sheet(s) bonded to the honeycomb core. If desired, the coils may be bonded to the cell walls by diffusion bonding or brazing.

Abstract: An engine shroud with integral honeycomb panel corners for use in the thrust reverser region of ducted fan gas turbine engines. The integral shroud is useful in a turbine engine having a core engine surrounded by an engine casing and nacelle, with a fan at the inlet directing air flow into the bypass duct between core engine and engine nacelle. The shroud basically consists of right and left ducts each having an approximately semicircular cross-section with radial flanges extending from the duct edges. The flanges permit the halves to be fastened together to produce a tubular shroud adapted to surround a gas turbine engine and form the inner wall of a bypass duct. The disclosed shroud eliminates the prior complex corner fittings connecting the semicircular center portion of the shroud to the extending flanges and provides simple, integral corners.

Abstract: An integral "C" duct for the thrust reverser region of ducted fan gas turbine engines. The integral duct is useful in a turbine engine having a core engine surrounded by an engine casing and nacelle, with a fan at the inlet directing air flow into the bypass duct between core engine and engine nacelle. The "C" duct basically consists of right and left "C" shaped ducts with bifurcations (radial flanges) permitting the halves to be fastened together to produce a tubular duct adapted to surround a gas turbine engine and form the inner wall of a bypass duct. The disclosed duct eliminates the prior complex corner fittings connecting the "C" shaped portion of the duct and the bifurcations and provides simple, integral corners.

Abstract: A method and apparatus for making a preformed maskant sheet having a plurality of perforations corresponding to a pattern of perforations desired in a structure. A shaping surface is prepared on a sheet having the contours of the structure to be perforated. The surface is perforated in the precise desired pattern. A plenum is secured and sealed to the back of the shaping sheet, enclosing all of the perforations. A line for introducing air into the plenum is connected to the plenum. A coating of maskant material is sprayed onto the surface (which has mold release properties) while positive air pressure is maintained in the plenum. Air flows out through the perforations, keeping them clear of maskant. The maskant is then cured and the resulting self-supporting sheet is removed from the surface and placed against the structure to be perforated. The holes may then be formed by any suitable method, such as grit blasting etching or the like.

Abstract: A system for selectively venting cool bypass duct air into selected locations between a gas turbine engine and the engine shroud. The venting system is useful in a turbine engine having a core engine surrounded by an engine casing and nacelle, with a fan at the inlet directing air flow into the bypass duct between core engine and engine casing. The venting system basically comprises tubes inserted in holes in the engine shroud which separates the bypass duct from the engine compartment. Often sensors, electronic components or the like are advantageously located in the engine compartment. However, elevated temperatures in the engine compartment often damages or degrades those components. The vent tubes are positioned so as to direct cool air onto those components. A large number of vents may be provided in the shroud as manufactured, each plugged at manufacture, with only those opened which are needed for a specific engine with specifically located heat sensitive components.

Abstract: A method and apparatus for making an insert for selectively, locally, densifying panels having a honeycomb core and at least one face sheet. At least two narrow, long foil strips are fed from supply rollers through a corrugating device which corrugates at least one of the strips. Preferably, the depth of corrugations vary greatly between adjacent strips. From the corrugating device the strips go to a take up reel which winds the strips into a flat pancake coil. When the desired coil diameter is reached the coil is secured to prevent unwinding and the coil is removed from the reel. The coils are used to replace portions of the honeycomb core to locally improve density, strength and thermal transfer characteristics of the panel.

Abstract: An improved synthesis for PMR-type polyimides, including first preparing a dimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'methylene dianiline. This dimer is then reacted with one of the following:1. the reaction product of a primary aromatic diamine and an aromatic dianhydride.2. an aromatic dianhydride.3. a mixture of a primary aromatic diamine and an aromatic dianhydride, or an ester of an aromatic tetraacid or an aromatic tetraacid.The resulting polyimide prepolymer exhibits superior physical properties and is substantially free of undesired impurities and unreacted 4,4'-methylene dianiline.

Abstract: An improved synthesis for PMR-type polyimides, including first preparing a dimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'methylenedianiline. This dimer is then reacted with the reaction product of the dimethyl ester (or dianhydride) of 3,3', 4,4'-benzophenonetetracarboxylic acid and 4,4'-methylenedianiline. The resulting polyimide prepolymer exhibits superior physical properties and is substantially free of the undesired trimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'-methylenedianiline. When this dimer is reacted with 3,3', 4,4'-benzophenonetetracarboxylic acid dianhydride methylenedianiline amic acid mixture, the resulting polyimide prepolymer exhibits superior physical properties.

Abstract: An improved synthesis for PMR-type polyimides, including first preparing a dimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'-methylenedianiline. This dimer is then reacted with the dimethyl ester of 3,3',4,4'-benzophenonetetracarboxylic acid and 4,4'-methylenedianiline. The resulting polyimide prepolymer exhibits superior physical properties and is substantially free of the undesired trimer of 5-norbornene-2,3-dicarboxylic acid, or acid ester or anhydride and 4,4'-methylenedianiline.

Abstract: A double layer structural honeycomb sandwich noise suppression panel for use in severe environments such as aircraft turbine engine housings. Two honeycomb core sheets having multiple cells transverse to the sheets are sandwiched around and bonded to a septum sheet consisting of a wire cloth sheet alone or bonded to a sheet of perforated material. A thin sheet of impervious material is bonded to one surface of the sandwich and a facing of thin perforated sheet material is bonded to the other sandwich surface. The panel has improved simplicity, structural strength with unusually light weight.

Abstract: A method and apparatus for draw forming a metal sheet over a male form to produce a three-dimensional shape. A sheet of metal is clamped between upper and lower draw plates positioned above the male form. The upper plate has an edge conforming to the male form shape. The plates and sheet are moved downwardly over the form with the edge of the upper plate firmly pressing the sheet against the form. The clamping pressure between the draw plates allows suitable slippage as drawing proceeds to produce a drawn shape of intended thickness. The drawn shape has a configuration conforming to the outer surface of the male form and has an outer surface of improved uniformity and appearance due to the wiping action of the upper plate edge.

Abstract: A pair of sheets of a metal capable of exhibiting superplasticity, such as Titanium, are placed in overlapping relationship and the peripheral edges of the sheets are joined, such as by welding, to provide a gas impervious seal. The joined metal sheets are lowered into a press so that they extend vertically between a pair of horizontally spaced apart, vertically extending preheated ceramic dies. The dies are previously transferred inside insulating shrouds from a preheater station before being loaded into the press. At least one of the dies is moved horizontally toward the other one of the dies so that the joined metal sheets are positioned closely adjacent to the dies. As a result, the metal sheets are heated to a predetermined temperature at which they are capable of exhibiting superplasticity. Thermostatically controlled heating platens behind the dies offset any heat losses in the dies as they radiate energy to the joined metal sheets.

Abstract: A ring insert for locally reinforcing a panel having a honeycomb core and at least one face sheet. The ring insert has at least two adjacent corrugated foil strips wound with the surface of the strips (and the corrugations) lying substantially perpendicular to the ring axis. The corrugations in adjacent strips have substantially different corrugation curve periods to prevent nesting of the corrugations of one strip into those of the next strip. The strips are bonded together to form a unitary ring. These inserts are adapted to be placed in cut-outs of corresponding shape in a honeycomb core and to be bonded thereto and to the panel face sheets. A method and an apparatus for winding the coil are also disclosed.

Abstract: A thrust ring assembly for use in a thrust reverser system for a gas turbine engine. The ring assembly is useful in a turbine engine having a core engine surrounded by an engine casing and nacelle, with a fan at the inlet directing air flow into the bypass duct between core engine and nacelle. The thrust reverser basically comprises at least one opening through the engine casing and nacelle, a turning vane cascade in the opening, a cover movable by an actuator between positions covering and uncovering the opening and at least one blocker door movable between a position allowing flow through the bypass duct and a position diverting flow to the turning vane cascade. The actuator and cascade are severely aerodynamically loaded during thrust reversal. The improved thrust ring assembly carriers those loads and transfers them to the engine casing. The forward ends of the cascade and actuator are secured to a bulkhead ring which is secured to the base of a frustoconical ring.

Abstract: The invention is directed a laminate structure using a reticulated adhesive material positioned between the honeycomb core and a perforate sheet and a precured reticulated adhesive between the perforated sheet and an outer layer of wire screen or other porous fibrous materials with similar pore openings therethrough through which the cells of the honeycomb core can communicate the atmosphere adjacent to the opposite side of the outer layer of porous material and a method of manufacturing same. During the manufacturing process of honeycomb noise attenuation structures which includes an imperforate sheet, an open cell honeycomb core, a perforated sheet and a layer of porous material stacked in that order a thin sheet of a reticulative adhesive material is positioned between the honeycomb core and perforated sheet and between the perforated sheet and the outer porous layer.

Abstract: A method and apparatus for superplastic forming and diffusion bonding of hollow metal parts. A forming assembly is prepared by surrounding a hollow tool (typically having a frusto-conical exterior) with a part blank having a corresponding shape, attaching parts, such as rings, to the exterior of the blank, then surrounding those parts with a skin blank. The forming assembly is placed in a pressure chamber, a heater is placed within the assembly and the chamber is sealed. The assembly of parts is heated to the diffusion bonding temperature of the parts while subjecting them to high gas pressure. The skin blank is deformed into intimate contact with the adjacent surfaces of the other parts and all of the parts are diffusion bonded together at all interfaces to form a unitary product. Gas pressure is released and the product is cooled and removed from the chamber and hollow tool. Any desired finish machining is accomplished and the productive is complete.

Abstract: An improved method of superplastic forming comprises the steps of selecting a relatively larger driver sheet and a relatively smaller part blank, both being made of Titanium, Titanium alloy or other metal capable of exhibiting superplasticity. A ceramic die is placed on a bottom wall of an upwardly opening ceramic forming chamber having sidewalls with upper edges. The ceramic chamber has an outer supporting steel jacket. The part blank is positioned over the die. The driver sheet is positioned over the part blank so that the peripheral edges of the driver sheet rest on the upper edges of the sidewalls of the forming chamber. A cover is provided for closing the chamber. It has a peripheral seal extending from an underside thereof. The cover and the chamber are clamped together in order to impinge the seal into a periphery of the driver sheet. The driver sheet and part blank are then heated to a predetermined temperature at which they exhibit superplasticity.

Abstract: A method is provided for achieving predetermined thickness requirements throughout a superplastically formed structure having extreme contours. A laminate assembly of sheets of a metal capable of exhibiting superplasticity, such as titanium alloy, is formed by a combination of superplastic forming and diffusion bonding. The shapes and positioning of the sheets is selected to provide extra metal where the greatest degree of stretching is necessary, such as around the lobes of an exhaust mixer for a turbofan aircraft engine. The gauge can thus be controlled throughout the structure while avoiding weak points and undue weight.