Abstract: In a gas turbine engine having a can annular combustion system, the diffusion passage between the outlet annulus of the engine compressor and the inlets to the individual combustion chambers located in an annular housing, is partially defined by diffusion control housings, one of each of which is integral with the upstream end of a respective one of the combustion chambers. Each diffusion control housing is wedge-like in planform and increases in circumferential width and radial height in the downstream direction. An opening is provided to receive a fuel injector and an air outlet or inlets is located at the upstream end of each housing. The air inlet can be in the form of a single opening at the apex of the housing or in the form of an opening in each flank of the housing.

Abstract: An optical device for monitoring variations in the distance between an object and a datum is particularly useful for monitoring running clearances in the demanding environment of a gas turbine engine. The device depends upon the principle that an image focussed by an astigmatic lens system changes shape as it passes through the focus. To monitor variations, e.g., in the working clearance between a turbine blade tip and a turbine casing, light from a light source is projected through an astigmatic lens system, onto the blade tip. Reflected light from the astigmatic image on the blade tip is passed back through the lens system and re-projected onto an image shape monitor which includes photo-cells. The photo-cells may be mounted in the main optical assembly or probe, or they may be distant from the probe and fed by light guides. Signals from the cells are combined to produce a monitor signal, the magnitude of which is a measure of the shape of the image on the blade tip, and hence of the clearance.

Abstract: A gas turbine engine blade tip seal consists of a sealing ring which is controlled by means of two annular control members. The members are arranged such that one control member has a relatively rapid thermal response rate and the other control member has a relatively slow thermal response rate, the sealing ring being controlled such that a preferred tip clearance is maintained under varying engine operating conditions.

Abstract: An air cooled turbine which has cooling air provided through pre-swirl nozzles into an annulus formed between radially inner and outer seals and then into cooling air inlets to the turbine blading, has leakage air deflector means to prevent the leakage flow from the inner to outer seal interfering with the cooling air flow. The deflector means may comprise leakage flow inlets adjacent the inner seal, channels extending radially and cooperating with the turbine rotor to provide passages for the leakage flow to a location radially outboard of the cooling air inlets to the turbine blading, and open portions through which the cooling air can flow to the cooling air inlets. The channel outlets of the deflector may be arranged so that some of the leakage flow can be directed to cool a less critical part of the turbine blading the remaining leakage flow being directed radially outboard of the cooling air inlets to a more critical part of the turbine blading which are arranged to receive the normal cooling air flow.

Abstract: A lubrication system comprises a chamber adapted to contain a lubricant and a duct to convey lubricant from the chamber to the apparatus to be lubricated. A pipe is adapted to introduce air into the lubricant flowing through the duct so that for a given flow rate through the duct the rate at which lubricant is withdrawn from the chamber is reduced when compared with the rate when no air is introduced into the lubricant flow.

Abstract: A rolling element bearing comprises two bearing races between which is disposed a cage including rolling elements, the radially innermost cylindrical surface of the cage including oil reservoirs and the inner race including lips which during operation of the bearing contact the oil within the reservoirs whereby the speed of the cage is adapted to be controlled by the inner race.

Abstract: A tank suitable for holding a lubricant is provided with a dipstick. A sleeve which is mounted on the tank and adapted to support the dipstick is interconnected with the output duct of the tank by means of a further duct. The arrangement is such that if the dipstick is incorrectly located in the sleeve, air is permitted to flow through the further duct into the output duct so that the pressure of the lubricant in the output duct is reduced. This pressure reduction consequently provides an indication of incorrect dipstick location.

Abstract: This device is aimed at solving the problem of varying sealing gaps between a rotatable turbine disc and fixed structure. Axial movement of the turbine disc relative to the fixed casing causes a ring coaxially carried in air bearings on the turbine disc for relative rotation and movement therewith, to operate at least one lever which in turn rotates a shaft. Rotation of the shaft operates further levers to cause seal rings operatively supported thereby, to precisely follow the axial movement of the turbine disc.

Abstract: A bearing chamber is provided with drains on both sides of the bearing thus preventing oil surges spilling oil over the chamber seals. The bearing chamber has three compartments and the chamber is pressurized by air passing through the seals at its ends. A main drainage duct drains the main bearing compartment via a scavenge pump to the oil tank. Passages through the bearings under normal operation drain oil from the end compartments to the central compartment compartment A. When the main drain becomes ineffective due to sudden surges of oil to the ends of the chamber the oil passes via auxiliary drainage ducts back to the tank due to the pressure in the chamber. Baffles are provided between the bearings and the end walls of the chamber to prevent the oil sloshing over the entrances to the auxiliary drainage ducts at excessive speed thereby providing tranquil zones from which the oil passes into the drainage ducts.

Abstract: A twin-engined VTOL/STOL aircraft comprising a rearwardly bifurcated fuselage 10 is proposed which in the event of failure of one engine 20 will allow the other engine 20 to produce a thrust which is not assymetric relative to the longitudinal axis of the aircraft. The fuselage 10 comprises a central front nose portion 11 and two side mounted engine nacelles 13, 14 which extend rearwardly to define spaced tail booms 15, 16. The engines 20 are preferably by-pass gas turbine engines in which the turbine exhaust gases are discharged through one or more nozzles 28 to the rear of the nose portion 11 between the tail booms 15, 16 on the center-line of the aircraft. The by-pass air is discharged through one or more nozzles 27 adjacent the longitudinal center-line of the aircraft. The nozzles 27, 28 are either swivellable, or other devices 34, are provided to vary the direction of thrust from the nozzles.

Abstract: A static shroud for a rotor comprises a shroud ring having a frustoconical inner surface adapted to co-operate with a peripheral portion of the rotor to define a small clearance therebetween. A plurality of actuators are provided to move the ring axially to vary the clearance in a predetermined manner. In order to compensate for eccentricity, the actuators are adapted to tilt the ring out of a radial plane when required.

Abstract: This invention relates to a bladed rotor for a gas turbine engine which comprises a disc having blade carrying slots in its periphery. In order to seal the spaces between the blade platforms and the disc an annular array of sealing plates is provided. The plates are supported directly from the disc by a rivet, pin or the like which passes through the disc in between the blade carrying slots, in this way avoiding any additional loading on the blades themselves.

Abstract: A marine propulsion unit which is mounted externally of a marine vessel and receives supplies of compressed air and fuel from on board the vessel, comprises a housing, a duct in the housing, containing a ventilated flow rotor, the rotor having tip blading driven by the products of combustion from combustion apparatus located in the housing.

Abstract: A gas turbine engine fuel injector has distinct and separate flow paths for liquid and gaseous fuel which each terminate in outlets of decreasing cross-sectional area in order to prevent combustion products from the flame tube or tubes of the engine from flowing back into the injector, the separate fuel flow paths preventing fuel from migrating from one path to the other. Compressor delivery air is also arranged to flow through the fuel outlets and some mixing of fuel and air takes in the outlets before the fuel enters the flame tube.The fuel injector is formed in two separate and co-operating parts, a fuel feed arm attached to the engine casing and readily removable through a relatively small access aperture in the casing and a fuel and air inlet means which is attached to the head of the flame tube and defines the fuel and air inlets into the flame tube.

Abstract: Apparatus for monitoring the state of a first circuit (19) by means of a second circuit (29) has an inductive coupling (23) linking the circuits across a gap (32). The second circuit embodies an oscillator (27) producing primary oscillations in that circuit and, through the coupling, secondary oscillations in the first circuit (19). If the state of the first circuit (19) is changed as by opening or closing of contacts (17,18), the resulting change in the impedance of the first circuit results in a change in the frequency of the primary and secondary oscillations. The second circuit (29) is connected to a detector (35) producing a signal (37AI) when the frequency changes. Instead of an inductive coupling, a capacitative coupling may be used.The apparatus is described as applied to a machine for measuring length. The first circuit (19) is embodied in a probe (12) whereby the machine contacts a workpiece to be measured. The first circuit is opened by such contact.

Abstract: A gas turbine engine fuel injector which burns liquid and gaseous fuel and also has a water injection system to reduce the formation of nitrogen oxides (NO.sub.x). The water can be discharged into a combustion chamber through an annular nozzle which is located between an inner annular fuel and air discharge nozzle and an outer gas discharge nozzle which comprises a circumferential row of discrete discharge nozzles. This allows the water to be injected at the most suitable point whichever fuel is being burnt. The water can also be injected into the inner annular fuel and air discharge nozzle.

Abstract: In order to produce a visual image on a screen of the movement of gas flows inside hollow bodies, e.g. gas turbine or internal combustion engines, or wind tunnels, a gaseous tracer material including a short-lived radio-active isotope is injected into the hollow body. Radiation detectors 32 are positioned around a gas turbine engine 10 and linked to a computer 36 which is programmed using an image reconstruction algorithm to reconstruct the flow path of the isotope in suitable form. One suitable isotope is produced by irradiating carbon tetrafluoride using a stream of deuterons from a cyclotron 12. The resulting reaction produces an isotope of Fluorine which has a half-life of 11.56 seconds, and decays producing radiation at approximately 1.6 Mev. The activity of the isotope is raised to the highest feasible level by continuously irradiating the tracer material in a chamber 14 as it is pumped around a circuit prior to injection. The half lives of the isotopes used are in the range 3 seconds to 2 minutes.

Abstract: U.S. Pat. No. 4,118,079 discloses a fluid bearing in which resilient shells are bent during operation of the bearing in response to changes in pressure of the fluid to make them conform more closely to the confronting surface defining the fluid gap. In the present invention a bearing of this type is used as an intershaft bearing by mounting the shells on one of the rotating shafts the problems associated with centrifugal forces on the shells being turned to advantage by mounting the shells on an external surface of one of the shafts to confront an internal surface on the other shaft. In an application of the invention to a gas turbine engine the two shafts are the high pressure shaft 10 and the concentric inner low pressure shaft 12. The bearing shells 34 of the air bearing 32 are mounted on resilient spring levers 36 on the slower low pressure shaft 12 and their convex surfaces confront the concave internal surface of the high pressure shaft 10, to define the air gap.

Abstract: A method of making a porous refractory shape comprises impregnating a sponge with a refractory material carried in a suspension, evaporating the suspension, placing the impregnated sponge on a plurality of rolling elements carried by a support base and firing the supported shape in a kiln.

Abstract: A thermal barrier coating adapted to provide a thermally insulating protective barrier on a component, the coating being capable of being applied to the components by spraying methods and being ductile when exposed to high temperatures. The coating comprises a mixture containing constituents of finely divided hollow glass microspheres; a ceramic frit of finely divided particles of alkali silicate titanate glass; and a refractory filler material of finely divided partiles such as micronized mica; aluminum oxide of mullite. All of the constituents of the mixture are suspended in a high temperature resistant binder material such as potassium silicate, sodium silicate or aluminum orthophosphate.