To restrict fluid flow between a high pressure working gas region and a low pressure lubricating oil sump in a gas turbine engine, a fluid bearing face seal includes a rotating mating ring confronted by a non-rotating carbon sealing ring with a face machined to provide an annular array of alternating lands and liftoff force-generating hydrodynamic lift pads, each comprising a three-step stairwell radially inwardly and outwardly bound by rails flush with the lands. An improved secondary seal includes a carbon mating ring to reduce seating drag forces on a piston ring biased into sealing engagement with a sealing ring carrier and a plurality of fluid orifices for pressure moment balancing the piston ring to the working gas pressure. To generate additional liftoff forces at low mating ring angularly velocities, the sealing ring face may also include an annular hydrostatic lift pad.

Fluid bearing face seal for gas turbine engines

A gas turbine engine comprising a combustion chamber (52), a turbine section (16) and a compressor section (12). The turbine section (16) surrounds the combustion chamber (52) and the compressor section (12) surrounds the turbine section (16).

Nested core gas turbine engine

A lightweight propulsor blade (10) is constructed 10 of a hollow internal spar (30) and an exterior airfoil shell (20) which defines and encompasses a hollow interior cavity (26). The internal spar (30) is disposed within the cavity 26 and extends spanwisely from its tip portion to terminate in a spar root portion (40). The spar has at least forward and aft spanwisely extending, chordwisely spaced, hollow box-like cavities (52A, 52B), a leading edge shear web (53) projecting chordwisely forward from the forward cavity (52A), a trailing edge shear web (55) projecting chordwisely rearward from the aft cavity (52B), and an intermediate chordwise shear web (57) spanning the space between and interconnecting the forward and aft cavities (52A, 52B). An additional intermediate box-like cavity (52C) may be incorporated in the intermediate chordwise shear web (57) in spaced relationship between the forward and aft cavities (52A, 52B).

Lightweight propulsor blade with internal spars and rigid base members

A method for molding composite structural plastic components is disclosed wherein such components are cast from a polymerizable thermoset or thermoplastic composition in a conventional metalcasting mold. In the instant invention, a low viscosity thermoset or thermoplastic composition having reinforcing fibers distributed therein is poured into conventional metalcasting molds, obviating the need for high heats and pressures associated with injection or compression molding of composite materials as taught in the prior art. In the case of a thermoset resin, the object to be fabricated is fully cured by the action of a catalyst at relatively low exothermic resin temperatures. In the case of a thermoplastic resin, curing is generally achieved independently of high added heat and pressure. If using a thermoplastic such as nylon 6 in the present invention, a preferred method of use involves the addition and combination of fiber reinforcements while the nylon 6 resin is being manufactured. The process for manufacturing nylon 6 involves three components: a monomer (i.e. caprolactam), an activator and a catalyst. The typical activator is HDI-caprolactame pre-polymer and caprolactam, and the typical catalyst is aliphatic cyclic amide, sodium salt. Typical activator and catalyst ratios are 0.50-3% by weight. Components used in the production of thermoplastic resins are often available in a solid form which must be liquefied so as to be suitable for pouring into a mold. One method of liquefying solid forms of caprolactam requires melting of the monomer into a liquid and then using a catalyst and activator to complete chemical transition into a flowable thermoplastic resin and ultimately a solidified part. The catalyst and activator complete the cure into a solid nylon 6 part without the need for high added heat or injection pressures. Caprolactam monomer is also available in a molten form and nylon casting activators can be acquired in liquid form, showing similar performance in the casting process and in the finished parts. However, all three components (monomer, activator and catalyst) are usually manufactured in a solid flake form. Whether thermoset or thermoplastic, the selected resin has a sufficiently low viscosity so as to allow mixture of the resin with high percentages of reinforcement fibers and suspension of the reinforcement fibers therein. During mixing and curing, the resin's viscid state prevents the fibers from settling or grouping, thereby achieving desirable dispersion of the fibers therein. This method furthermore enables fabrication of high quality composite structural plastics in traditional soft molds and molds produced using rapid prototyping techniques. The mold itself may be made by constructing a pattern of the object to be molded and casting the mold in a liquid or soft formable material such as wax, plastic rubber or spray metal which may use extractable cores therein. Structural plastic molds made with this process can be used for prototype or production purposes. This economical molding technique permits production of quality structural molds and plastics utilizing low cost molds heretofore used only in the prototyping of plastic visual aids.

Method for molding composite structural plastic and objects molded thereby

The gas turbine stator vane structure comprising a plurality of vanes 13, an outer platform 11 and an inner platform 12 is formed by integrally connecting a plurality of units 2 in a circle with fiber-reinforced prepreg tapes 10, 10′ each wound around and fused to an outside surface of the outer platform 11 and an inside surface of the inner platform 12. Each of the units 2 is constituted by (a) a core 3 composed of a laminate of fiber-reinforced prepregs and integrally having a web 31 for constituting a vane 13, and flanges 32, 33 integrally connected to both ends of the web 31 for constituting outer and inner platform pieces 21, 22; and (b) a skin layer 4 integrally molded around the core 3. The core 3 is at least partially exposed through windows of the skin layer 4 on both of an outside surface of the outer platform piece 21 and an inside surface of the inner platform piece 22, and fused to the fiber-reinforced prepreg tapes 10, 10′.

Gas turbine stator vane structure and unit for constituting same

A gas turbine engine disc having integral, radially extending aerofoil blades and an integral shroud interconnecting the radially outer extents of the blades is described. In the manufacture thereof continuous fibres are wound around an annular array of inserts provided in a dividable disc. The inserts define the spaces between adjacent blades on the disc. A mixture of chopped carbon fibre and an epoxy resin matrix material is then injected into the central portion of the die interior. Any part of the wound fibres which has not been impregnated by the chopped fibre/resin matrix material is subsequently impregnated by a matrix material whereupon the die is opened to release the thus produced bladed disc.

Method of manufacturing an annular bladed member having an integral shroud

A hollow aerofoil cross-section aircraft propeller blade is provided with a tow of KEVLAR fibres internally thereof. The fibres which are anchored to the blade root and tip portions are arranged to be passive under all normal operating conditions of the blade. However in the event of a structural failure of the blade between its root and tip portions the fibres serve to contain the blade tip together with any portion of the blade attached thereto. The invention is additionally applicable to prop-fan and fan blades for gas turbine engines.

Hollow aerofoil blade

A method of manufacturing a bladed disc from a fiber reinforced composite material which comprises injecting a mixture of short fibers and a matrix material into a dividable die so configured as to define the form of a disc having integral radially extending aerofoil blades. The mixture is injected into the die at such a location that the short fibers within the aerofoil-defining portions of the die are radially aligned. The die contains two support rings which are coaxially disposed within the bladed disc after injection molding so as to provide radial support for the aerofoil blades of the thus formed bladed disc. The method may be modified to provide the bladed disc with an integral shroud.

Method of making an integral bladed member

An annular bladed member having an integral shroud and a method of manufacture thereof

A seal arrangement suitable for sealing between two coaxially mounted, axially restrained, radially spaced apart and relatively rotatable members comprises two concentric, ring-shaped seal elements having adjacent sealing faces. The seal elements are mounted on the respective members by a spline and groove arrangement which permits radial growth or shrinkage of the relatively rotatable members due to their thermal expansion or contraction without such growth or shrinkage being transferred to the seal elements. The arrangement insures that the gap between the sealing faces of the seal elements remains substantially constant during thermal variations.

James Pears Angus

Papers

Method of manufacturing an annular bladed member having an integral shroud

Hollow aerofoil blade

Method of making an integral bladed member

An annular bladed member having an integral shroud and a method of manufacture thereof

Dual-ring seal with temperature compensation