Abstract: A device for controlling fuel pressure and delivery as necessary for the operation of the servovalves of an aircraft engine is disposed downstream of a fuel injector feed unit of the engine. The device comprises a chamber maintained at the servovalve feed pressure by the movement of a closure member to vary the opening of a port of the chamber. The closure member moves under the action of opposing forces comprising inter alia a force in the opening direction proportional to the servovalve feed pressure. An equilibrium position of the closure member is a function of pressure resulting from the engine speed. An injector delivery control loop is therefore isolated from a servovalve pressure and delivery control loop.

Abstract: A process for producing a hollow article made of a composite material of reinforcing fibers embedded in a matrix of hot-polymerized resin includes a step in which at least one core made of a silicone elastomer is draped with at least one layer of resin-impregnated reinforcing fibers. A resultant assembly is moulded to shape the internal and external surfaces of the hollow article by simultaneous inward and outward compression of at least one resin-impregnated fiber layer caused by movement of mould walls towards each other and by thermal expansion of at least one core.

Abstract: A method of so-called “ultrasonic” peening is described for peening large sized annular surfaces on thin parts. The method uses a microbead mist vibrated in a chamber with an opening so that the surface that is to be peened makes at least five movements past the opening of the peening chamber during peening so as to reduce deformation of the part.

Abstract: An integrated exhaust nozzle and thrust reverser for a turbojet engine is provided. The exhaust nozzle comprises an exhaust duct situated within a fairing (9), a set of hot flaps (14) at a downstream end of the duct, a set of cold flaps (16) at a downsteam end of the fairing (9), and a thrust reverser (30). The thrust reverser comprises two eyelids (31, 32) which are movable between a thrust reversal position wherein they project into the duct and a forward-thrust position. In a takeoff mode, the eyelids (32, 33) are moved away from each other by one or more actuators (50) acting on arms (33, 34) pivotably connected to the eyelids (31, 32). Movement of the eyelids (31, 32) from the reverse-thrust position to the forward-thrust position, or vice-versa, is implemented by control actuators (35, 36).

Abstract: A process for the manufacture of a thin ceramic core involves casting a band of uniform thickness on a support from a solution of a ceramic material based on silica and zircon in a binder, drying the band, shaping the band in a mold and carrying out preheating and pressing of the band in the mold, baking the component thus obtained in a ceramic preform, and then carrying out an impregnation. The thin core obtained can be assembled together with another thin core and/or on a conventional thick central core, and can be used in precision casting such as in the production of turbine blades.

Abstract: A system for cooling the lubricant of the speed reducer of an aircraft turboshaft-engine during high-speed flight and during low-speed taxying. The cooling system includes a radiator through which the lubricant flows. An air supply duct delivers cooling air over the radiator. An air discharge duct discharges the air into the exhaust nozzle of the engine. The air supply duct is fed by an arcuate air take-off slot disposed in the air intake of the engine. The air discharge duct is provided with a flap for slowing air flow through the cooling system, and with an ejector-mixer, which is fed by compressed air, taken from the engine compressor, for creating a Venturi effect to increase air flow through the cooling system when required.

Abstract: The drive system of a propeller driven transport aircraft has first and second propeller doublets mounted in the plane of the aircraft wings, each propeller doublet including two propellers disposed symmetrically on opposite sides of the central longitudinal axis of the aircraft. The first and second propeller doublets are driven independently of one another by first and second engine units via first and second independent drive trains respectively, the first and second engine units being disposed side by side in the aircraft fuselage.

Abstract: A method for the early detection of aerodynamic instability in a turbomachine compressor is described which involves collecting and normalizing signals from sensors distributed uniformly around the circumference of the compressor and detecting events for which the normalized signals do not pass through a zero value during a length of time Tz which is at least greater than the time taken for two successive moving blades to travel past the sensor. A decision regarding the imminence of aerodynamic instability is then taken after the detected events have been analyzed and decision criteria have been applied. The decision criteria may be based on the event detection rate and/or on the spatio-temporal position of the events detected across all the sensors.

Abstract: A ceramic heat barrier coating is deposited on a substrate so that the coating has a columnar growth pattern which is interrupted and repeated a number of times throughout its thickness by successive regermination of the ceramic deposit. The regermination is obtained by a vapour phase deposition process wherein a polluting gas is introduced intermittently during the deposition of the ceramic. The resulting ceramic coating has a lower thermal conductivity than conventional columnar ceramic coatings.

Abstract: A lubricant drainage circuit outside a roller bearing is fitted such that an output draining through a drained ring is controlled by providing drainage channels crossing the ring and having different inclinations in a circumferential direction of the drained ring.

Abstract: This axial mounting of the bottoms (5) of fan blades provides two levels of flexibility, and features rather low stiffness after using up a predetermined clearance (35) between two stop parts (32, 34), which then imposes a significant increase in stiffness; however significant energy was able to be absorbed through the elastic deformation of certain parts (7, 30) located between the blade and the disc (2), which enables the blade to withstand rather significant momentary forces, for example if a neighboring blade breaks and strikes it.

Abstract: A thrust reverser for a turbofan jet engine having a stationary structure defining an upstream part of a fan cowling and an axially displaceable, annular structure located downstream of the stationary structure, wherein the inner surface of the fan cowling is spaced from an outer surface of an engine cowling to form an annular duct. A plurality of flaps form a portion of the inner surface of the fan cowling during a forward thrust position, and in a reverse thrust position, the flaps pivotably rotate about a stationary pivot so that their first edges are adjacent with the outer surface of the engine cowling to block the annular duct. A plurality of thrust reverser baffle portions are covered by the flaps during the forward thrust position, and during the reverse thrust position, the thrust reverser baffle portions cover a passageway in the fan cowling between the stationary structure and the displaceable structure.

Abstract: A main filter for an airplane fuel circuit or a fuel circuit for any type of mechanism, the filter having a first and second entry, which go directly into a chamber containing a filtering unit, the first entry receiving the fuel at a temperature essentially equal to that of the second entry which receives a hotter fuel which has passed through a heat exchanger. The filter prevents clogging due to ice formation on the filtering unit of the filter or at least inhibits such clogging. A fuel circuit using such a filter is also disclosed.

Abstract: A ceramic heat barrier coating is deposited on a substrate so that the coating has a columnar growth pattern which is interrupted and repeated a number of times throughout its thickness by successive regermination of the ceramic deposit. The regermination is obtained by a vapour phase deposition process wherein a polluting gas is introduced intermittently during the deposition of the ceramic. The resulting ceramic coating has a lower thermal conductivity than conventional columnar ceramic coatings.

Abstract: An apparatus for manufacturing a hollow turbomachine blade made from a titanium alloy of the TA6V type includes a hot twisting step in which an element of the blade is twisted progressively at a temperature above 700° C. by a plurality of bars which are rotated about the twist axis and act on collars previously fixed to the element, the distribution and number of collars being determined according to the desired twist to be imparted and such as to obtain a linear twist development between each collar.

Abstract: A method of improving the oxidation and corrosion resistance of a superalloy article comprises providing a superalloy substrate having a sulphur content which is less than 0.8 ppm by weight, and depositing on the substrate a protective antioxidation coating having a sulphur content also less than 0.8 ppm by weight. A heat barrier layer may also be provided by depositing on the protective anti-oxidation coating a ceramic coating of columnar structure.

Abstract: A process for assembling titanium aluminide articles by diffusion brazing comprises the following steps: (a) Preparation of a homogenous mixture of a titanium aluminide powder A of 40 to 90 weight % and a powder B chemically wetting A and having an appreciably lower melting point; (b) formation of a paste by addition of an organic binder to the powder mixture; (c) depositing the paste plumb on the assembly gap; and, (d) heating the assembly in a vacuum furnace between 1000° C. and 1300° C. for a period of from a few minutes to 6 hours. This process is also of use for repairing and refacing titanium aluminide articles.

Abstract: A process for manufacturing a hollow turbomachine blade made from a type TA6V titanium alloy includes a hot forming step in which an element of the blade is isothermally shaped in a press at a temperature between 700° C. and 940° C. under the action of at least two stamps and a holding-clamp which press the blade element on a shaping die, while ensuring a controlled deformation rate so as to obtain a lengthening of the fibers, that is to say the elongation of the different fibers of the element, with a controlled distribution on both sides of the central fiber. A multiple-action furnace-press designed for carrying out the process is also described.

Abstract: The present invention relates to the high-pressure turbine stator ring of a turbo engine that is fastened to the stator by tightening means that limit leaks to a minimum. These means mainly comprise a tightening grip (40) that grips the curved section of a downstream leg (35V) of each spacer section (30) that is fastened to the turbine casing (1) of the stator by a curved downstream flange (23V) of each ring section (20). Application to the fastening of the high-pressure turbine stator ring of a turbo engine.

Abstract: An exhaust assembly for a jet powerplant of a supersonic airplane comprising a rear structure fitted with a thrust reverser. The rear structure includes a primary multi-flap nozzle of variable cross-section situated downstream of a primary duct, a secondary multi-flap nozzle of variable cross-section situated downstream of a secondary duct enclosing the primary duct and a fairing enclosing the secondary duct and fitted with a throat downstream of an exhaust orifice of the secondary nozzle, the throat being followed by a diverging portion. The thrust reverser comprises two eyelids affixed in a pivotable manner to the fairing, one on each side to of an axial plane of symmetry. The eyelids are movable between an active, thrust-reversal position wherein the eyelids project transversely into a gas jet downstream of the fairing to deflect the gas jet in a forward direction for thrust-reversal and an inactive, forward-thrust position wherein the eyelids are situated in an extension of the fairing.