Abstract: The invention relates to hammer-fastener blade-locking device affixing the blades in the channel (2) of a turbojet-engine rotor disk (1) and comprising a case (15) of which the cross-section matches that of the channel (2), further a locking element (16) mounted in radially displaceable manner in a traverse orifice in the case (15) and receivable in part in a lock housing (9a, 9b), and a drive bolt (17) acting on the locking element (16). The locking element (16) comprises stops (32a) sliding in windows (22a) of the case (15). The bolthead (4) is large and is radially affixed between the bottom of the channel (2) and the base (20) of the case (15).

Abstract: The cryogenic propulsion module comprises a main cryogenic thruster (10), two attitude-controlling secondary thrusters (21, 22), tanks (31, 32, 33, 34) for feeding cryogenic propellants, a device for intermittently pressurizing the tanks (31, 32, 33, 34), and a device for initiating firing of the main cryogenic thruster (10) in intermittent manner while the tanks (31, 32, 33, 34) are intermittently pressurized. The device for intermittently pressurizing a tank (31, 32, 33, 34) comprises a heat exchange circuit associated with a heat accumulator (61, 62) and a device (71, 72) for putting a predetermined quantity of a propellant into circulation in the heat exchanger circuit. The module also comprises a device for heating the heat accumulator (61, 62) in the periods between two consecutive firings.

Abstract: A sheet metal sealing sleeve placed under a pair of juxtaposed blade platforms in a turbomachine so as to cover the gap between them is provided with apertures to allow the flow of a ventilating gas to the platforms. The apertures are provided in bosses formed on the sleeve to define chambers between the sleeve and the platforms which provide for greater heat exchange by virtue of the forcible impact of the gas blown through the apertures under the platforms. The sleeve also aids in damping platform vibration.

Abstract: The invention provides a process for checking the bonding of the cellular core of a honeycomb to a skin, said process comprising the steps of: using a light source to illuminate a so-called illuminated zone on the free surface of the honeycomb so as to illuminate the interior of the cells opening out into said illuminated zone, and detecting the emergent light exiting the cells in a so-called observed zone. The minimum distance between said illuminated zone and said observed zone is denoted E and defines a direction D, the distance E being at least equal to the width L1 of the cell mouths measured in the direction D, so as to make it impossible for the illuminated zone and the observed zone to be simultaneously above the mouth of one and the same cell. The invention also provides an instrument for implementing the process.

Abstract: A method for extending the life of the attachments that attach blades to rotors, particularly for aerojet engines. Such a method is notable in that it employs intensive ultrasonic peening of the grooves and of the roots of the blades, this peening being performed with an Almen intensity at least equal to F8A, so as to increase the compressive prestress in the contact surfaces without increasing the roughness of these surfaces.

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 vapor 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 turbine vane with an enhanced profile including a trailing edge is curved inwards towards the suction face in the vicinity of the head, as if it was twisted, which opens the vane and limits leakage currents above the head. The flow is thus improved since the eddies formed by the irregular flows in front of the vane are reduced.

Abstract: The servovalve comprises an electric motor and a distributor valve integrating a hydraulic slide under the control of said electric motor and further comprising two load channels pierced in a central rod on which blocks are mounted for co-operating with communication orifices of the distributor valve and co-operating with one another and with the ends of the hydraulic slide to define annular chambers including two load chambers connected to the receiver member to be controlled. The two load channels put each of the load chambers into communication respectively with an immediately adjacent annular chamber so as to ensure that the same pressure exists on both sides of the blocks separating said two chambers.

Abstract: While one preform (A) is being shaped between two dies (4, 11), another preform (B) is being prepared by heating in a compartment (14) on a lower die (5) similar to the preceding one (4). When the preform (A) has been shaped, a mobile section (3) of the furnace is lifted to release the upper die (11) and make it possible to place the new preform (B) and its lower die (5) beneath it. Thus, when one preform has been shaped, the following one is already prepared by heating.

Abstract: A fuel injection system in a turbomachine, the system comprising a high pressure pump for pressurizing the fuel coming from a fuel tank to a high pressure P1, a plurality of fuel injectors disposed in a combustion chamber of the turbomachine, and a metering unit interposed between said high pressure pump and said plurality of injectors to control the rate at which fuel flows into the injectors from the high pressure pump, wherein said metering unit comprises a pressurization valve piloted to occupy two pressure levels by means of a metering valve fed with fuel from said high pressure pump. A solenoid stop valve for acting on the pressurization valve is also provided to interrupt the feed of fuel to the injectors.

Abstract: In a turbomachine whose speed of rotation is controlled by means of a throttle control lever acting via an electronic control circuit, a system is provided to provide protection against excess speed, the system comprising means for limiting the fuel feed of the turbomachine to a predetermined fixed flow rate Wps when the speed of rotation exceeds an authorized maximum speed, means for maintaining said fuel feed at said predetermined fixed flow rate while the speed of rotation drops below the authorized maximum speed, and means for reducing said fuel speed to a flow rate Wr corresponding to an idling speed when the throttle control lever issues an idling control to the turbomachine via the electronic control circuit.

Abstract: Part of the flow of reactive gas admitted into the enclosure (10) is guided to the inside of the volume defined by a concave inside face of the or each hollow-shaped substrate (S1, S2, S3) so that said concave inside face is swept in full by a fraction of the total admitted gas flow.

Abstract: An assembly method in which a brazing metal is initially filled into radial wells pierced in an annular injection piece having first injection orifices for discharging a primary fuel, and in a cylindrical endpiece surrounding the annular injection piece and having secondary injection orifices for discharging a secondary fuel; thereafter the annular injection piece is fitted inside the cylindrical endpiece and these pieces are together fitted on a first tube for feeding primary fuel and a second tube for feeding secondary fuel and surrounding the first tube, and also to an outer wall of the injector; finally, the end portion of the injector as assembled in this way is placed in an enclosure where it is heated so as to melt the brazing metal to unite the parts.

Abstract: An injector of a two-headed combustion chamber of a turbomachine has a first feed tube which is connected to an annular injection piece for discharging primary fuel into the combustion chamber. It also has a second feed tube surrounding the first feed tube and connected to a cylindrical endpiece for discharging secondary fuel into said combustion chamber. This endpiece has an annular channel of diameter that is greater than the diameter of the second feed tube and that extends over its entire length. A third tube is provided that surrounds the second tube and that is connected to a tubular separation element which is inserted in the annular channel of the cylindrical endpiece so as to form two annular spaces in which a cooling fluid can flow over 360° all the way to the end of the injector.

Abstract: The invention relates to a method for the ultrasonic peening of annular recesses for the attachment of blades to a rotor rim, these recesses including a blade introduction opening. According to the method, a plurality of beads is placed on a vibratory surface of a sonotrode, arranged in an intermediate position in a sleeve having opposed closing-off means capable of sliding in the recess, the introduction opening is placed facing the sonotrode, the sonotrode and the sleeve are moved together toward the introduction opening into a peening position in which the closing-off means face the recess ends opening into said opening, then the rotor rim is turned about its axis so as to bring the closing-off means into a first end of the recess so as to form a closed chamber containing the beads. The rim is turned and the vibratory surface is vibrated to mobilize the beads within the chamber, thereby peening the recess.

Abstract: The flap comprises a structural beam which is formed integrally with a structural core for a vane, and fastening portions, and a composite envelope surrounding the structural core and forming at least the aerodynamic profile of the vane.

Abstract: A tool for holding a blade blank (1) comprises a frame (13) in which a control system using clamping jaws (18, 19) and lifters (30, 34, 35) grips the blade and holds it in position vertically on two supporting faces (22, 23), while the blade has been laid on three lateral faces (41, 42, 43). The blade is thus simultaneously held in a precise position and gripped sufficiently tightly, with a single control main mechanism. The mounting of the blade is thus greatly simplified and it may be subjected without further precaution to a manufacturing operation such as welding by friction to a rotor disk.

Abstract: A protection device for protecting a control mechanism of inlet guide-vanes of a turbojet engine includes a narrowed section on a connecting rod. The connecting rod is for transmitting the movement of a spindle of a piston of the control mechanism or actuator to a control ring that directs all of the inlet guide-vanes. The narrowed section of the connecting rod is a frangible part.

Abstract: A part is used that constitutes a platform web and that has a shape close to the shape of the platform with an inside face and an outside face that are opposite each other. Fiber reinforcement plies are draped on a blade core and at least some of these plies extend beyond an end of the blade that is to be connected to the platform so to form ply extensions. The ply extensions are folded down against the inside and outside faces of the platform to form flaps securing the blade to the platform, and fiber reinforcement plies are draped around the platform web and over the flaps so as to form a platform box holding the flaps prisoner.

Abstract: These objects are achieved by a method of acoustically inspecting a one-piece bladed wheel in which the wheel is driven in rotation; each blade of the wheel is subjected to mechanical excitation; its acoustic response is picked up and a corresponding electrical signal is generated; its frequency response is determined by computing a FFT; the electrical signal and the associated frequency response are stored; the characteristic frequencies of each blade of the wheel are identified; and a wheel is rejected or accepted depending on whether or not the frequency distribution obtained in this way matches a predetermined set of forbidden frequency distributions. Advantageously, an additional step is provided in which the defects of a blade are determined by comparing its frequency response with predetermined frequency responses that are characteristic of various types of defect.