Abstract: The invention relates to a system for driving an accessory, such as a fuel pump or an oil pump in a turboengine, said system comprising an electric motor and further comprising an air turbine associated with said electric motor. Said air turbine is suitable for being fed with a flow of air taken from a compressor of said turboengine and contributing to driving the accessory. The system also includes a valve for controlling the flow of air taken from the compressor, which valve is in the closed position while the turboengine is starting.

Abstract: An emergency device for relighting a windmilling turbojet, the jet comprising a fan driven by a low-pressure turbine via a first shaft and a compressor driven by a high-pressure turbine via a second shaft disposed coaxially around the first shaft, a differential interconnecting said first and second shafts while compensating for their different speeds of rotation in normal operation or the turbojet, and a braking system connected to the differential so as to enable it to be slowed down or blocked when the turbojet shuts down, thereby enabling the first shaft to entrain the second shaft so that it reaches a speed that favors relighting of the turbojet.

Abstract: An electrohydraulic device for varying the pitch of the blades of a machine rotor, the blades being mounted on a hub rotated by a drive shaft of the machine, and each blade having a root capable of pivoting about a longitudinal axis of the blade, the drive shaft itself being rotated relative to a stationary structure of the machine, the device comprising firstly a hydraulic actuator whose piston is secured to a control and synchronization ring in which off-center wrist pins are engaged, each fixed in register with one of said blade roots, and having a cylinder closed by a cover that includes a high pressure hydraulic pump feeding hydraulic fluid to both faces of said piston via channels integrated in said cylinder of the actuator, and secondly an electric motor controlled and powered by an electricity generator comprising an inductor secured to said stationary structure of the machine and an armature secured to said drive shaft of the machine.

Abstract: An electrohydraulic actuator comprising: a hydraulic actuator comprising a piston secured to a member to be controlled and capable of moving in a cylinder under drive from a hydraulic fluid; a hydraulic pump feeding both faces of the piston with hydraulic fluid via channels integrated in the walls of the cylinder; an electric motor immersed in the hydraulic fluid, and controlled and powered electrically by an electronic control unit, driving the hydraulic pump in rotation; and a hydraulic accumulator for compensating variations in the volume of the hydraulic fluid; the hydraulic actuator, the hydraulic pump, the electric motor, and the hydraulic accumulator having a common axis of symmetry and being mounted in alignment in a common housing that is leaktight to the hydraulic fluid, thereby forming an axially symmetrical self-contained hydraulic assembly.

Abstract: A variable cycle propulsion system for a supersonic airplane, the system comprising at least one engine having at least one compressor and capable of generating thrust for supersonic flight speeds, and at least one auxiliary propulsion assembly separate from said engine, and capable of generating additional thrust for takeoff, landing, and subsonic cruising speeds, at least one pipe connecting the engine to the auxiliary propulsion assembly to convey thereto compressed air produced by the compressor so as to enable the auxiliary propulsion assembly to generate additional thrust for takeoff, landing, and subsonic cruising flight, there being at least one valve enabling the pipe to be closed off for supersonic cruising flight.

Abstract: An emergency device for relighting a windmilling turbojet, the jet comprising a fan driven by a low-pressure turbine via a first shaft and a compressor driven by a high-pressure turbine via a second shaft disposed coaxially around the first shaft, a differential interconnecting said first and second shafts while compensating for their different speeds of rotation in normal operation or the turbojet, and a braking system connected to the differential so as to enable it to be slowed down or blocked when the turbojet shuts down, thereby enabling the first shaft to entrain the second shaft so that it reaches a speed that favors relighting of the turbojet.

Abstract: A variable cycle propulsion system for a supersonic airplane comprises at least one engine capable of generating thrust for flight at supersonic speeds together with at least one auxiliary propulsion assembly that is separate from the engine and that is capable of generating additional thrust for takeoff, landing, and flight at subsonic speeds. The auxiliary propulsion assembly does not have a gas generator and means are provided for transmitting a fraction of the mechanical power produced by the engine to the auxiliary propulsion assembly in order to enable it to generate the additional thrust for takeoff, landing, and subsonic cruising flight. Means are provided for decoupling the mechanical transmission means for supersonic cruising flight.

Abstract: A variable cycle propulsion system for a supersonic airplane, the system comprising at least one engine having means for producing exhaust gas and a gas exhaust nozzle for generating thrust for supersonic flight speeds, and at least one separate auxiliary propulsion assembly dissociated from said engine, having no gas generator, and capable of generating thrust for takeoff, landing, and subsonic flight speeds. The system further comprises gas flow tapping means movable between a position in which they tap off at least a fraction of the exhaust gas produced by said engine and feed it to said propulsion assembly to enable it to generate thrust for takeoff, landing, and subsonic cruising flight, and a position in which the gas produced by the engine is directed solely to the engine nozzle for supersonic cruising flight.

Abstract: A titanium-based intermetallic alloy having a high yield stress, a high creep resistance and sufficient ductility at ambient temperature has the following chemical composition as measured in atomic percentages:Al, from 16 to 26; Nb, from 18 to 28; Mo, from 0 to 2; Si, from 0 to 0.8; Ta, from 0 to 2; Zr, from 0 to 2; and Ti as the balance to 100; with the condition that Mo+Si+Zr+Ta>0.4%.Production, working and heat-treatment ranges adapted to the intended use of the material are also defined.

Abstract: Screw or nut braking rings and mountings established with the rings include a nut having an upper portion hollowed from a circular throat. Slits divide the upper portion into blocks by cutting the throat. A shape-memory alloy ring is housed in the throat so as to retighten the blocks on the threaded portion of the mounting and thus tighten it. The ring exhibits a change between the tightening state and a mounting state where it is free in the throat and can be easily mounted.

Abstract: A turbojet having an air intake case including radial arms between an outer annular structure and an inner central structure, and a deicing unit configured to deice the radial arms by microwaves and located in the central structure. The deicing unit has a microwave generator and a transmitting element configured to transmit energy and including an inside annular waveguide located inside of the central structure. An energy distributing element configured to eliminate ice is coupled with the transmitting element by a coupling element. The radial arms are made from a dielectric composite material.