Abstract: The invention relates to a telescopic shock absorber for an aircraft undercarriage, the shock absorber comprising a strut (1) in which a rod (2) is mounted to slide, the shock absorber including controlled retraction means (41 . . . 43) for retracting the rod into the strut to a retracted position. The shock absorber includes positive retention means (27, 29) for retaining the rod in the strut and adapted to retain the rod in the retracted position when the rod is moved thereto by the retraction means, the positive retention means being arranged, at least in the event of a severe landing of the aircraft, to allow the rod to be pushed into the strut beyond the retracted position.

Abstract: The invention relates to a method of controlling an electromechanical brake for a vehicle wheel, the brake including an actuator provided with a pusher that is actuated by an electric motor and that is adapted to exert a braking force selectively on friction elements in response to an actuation setpoint, the method comprising the following steps: from a braking setpoint ( F), determining a nominal position setpoint ( X) for the brake actuator; from said braking setpoint ( F), estimating a reference current (i*) that ought normally to be flowing in the motor of the actuator to apply a force equal to the braking setpoint; comparing the reference current (i*) with a current (i) actually flowing in the motor of the actuator, and deducing a position correction (xcorr); and adding the position correction to the nominal position setpoint.

Abstract: The invention relates to a wheel brake for a vehicle, in particular for an aircraft, the brake comprising a support (2) that receives at least one electromechanical actuator (1) fitted with a pusher (8) facing friction elements (3) and movable under drive from an electric motor (6) to apply a braking force selectively against the friction elements. In accordance with the invention, the actuator is non-reversible such that a reaction force applied on the pusher cannot cause the electric motor to turn, and the actuator is associated with means (30, 31, 32, 33, 34) for selectively switching off an electric power supply to the electric motor, which means allow power to be delivered to the actuator in normal circumstances, and switch off said power if: the measured speed of rotation (?mes) of the electric motor drops below a first predetermined threshold (S1); and the commanded speed of rotation ( ?) of the electric motor drops below a second predetermined threshold (S2).

Abstract: A method of distribution braking between the brakes of an aircraft. The method includes a first step of estimating a braking force objective and a steering torque objective to be achieved by the brakes of the aircraft. It also includes the steps of defining at least two groups of brakes (12, 13) and determining, for each group, a braking level that is to be achieved by the group. The braking levels being calculated in such a manner that braking performed in application of the braking levels is, at least under normal operating conditions of the brakes, in compliance with a braking force objective and with a steering torque objective.

Abstract: A deep hole boring head is provided which is capable of rotating about a central axis, a body whose front part has at least one cutting edge followed by a recess which leads to a duct inside the body, this duct allowing the chips formed during the boring to be cleared away rearwards, and includes at a front end thereof and at a center portion thereof a pilot drill bit capable of guiding the head during boring. Use for the boring of a production piece is made of titanium, the ratio L/D between the depth L of the hole bored and the diameter D of the latter being greater than or equal to 10, and the diameter D being greater than or equal to 65 mm.

Abstract: A pipe for feeding a gas into an oven, a furnaces, or the like (such as a CVI/CVD oven), and in particular into a reaction chamber structure inside the oven, is provided with a gastight tubular sealing device extending radially outward of the pipe and defining a path that is practically gastight, through which there extends the feed pipe. The tubular sealing device is preferably at least partially flexible in the transverse direction and/or the axial direction so as to accommodate positioning defects between a location situated in the reaction chamber and a location where the gas feed pipe penetrates the oven (which defects may be due, for example, to asymmetrical thermal expansion/contraction).

Abstract: Radio-frequency transmission device comprising a transmission antenna (2) and a receiving antenna (4), characterized by comprising one or more passive resonant circuits (5) positioned between the transmission and receiving antennas (2, 4).

Abstract: A method and apparatus for reducing the noise generated by an aircraft undercarriage when the aircraft is flying and the undercarriage is deployed, includes coating at least a portion of a structural element of the undercarriage in a material that is of lower density than the material of the structural element in order to give this portion an aerodynamic shape suitable for smoothing a stream of air flowing around the portion.

Abstract: The invention relates to a method of feeding energy to actuators associated with the undercarriages forming the landing gear of an aircraft, the aircraft comprising: a main power supply that operates independently of rotation of wheels carried by the landing gear; and a local power supply comprising one or more local generators, each driven by rotation of a wheel carried by an undercarriage; the method of the invention comprising the following steps: in a nominal mode of operation, powering said actuators by the local power supply; and in an additional mode of operation, when the delivery of energy by the local power supply is not sufficient, providing additional energy or all of the energy required by said actuators by means of the main power supply.

Abstract: A coherent fiber preform made of carbon fibers presents holes formed from at least a first face of the preform, and the preform is densified by depositing therein a material constituting a matrix by means of a chemical vapor infiltration type process. The holes are formed by causing a plurality of non-rotary elongate tools to penetrate simultaneously, the tools being substantially mutually parallel and presenting on their surfaces roughnesses or portions in relief suitable for breaking and/or transferring fibers they encounter, the tools being caused to penetrate simultaneously by moving a support carrying the tools, and the tools being selected to have a cross-section that makes it possible to obtain in the carbon fiber preform holes that present a cross-section with a mean dimension lying in the range 50 ?m to 500 ?m.

Abstract: The invention relates to a method of managing an electromechanical brake actuator comprising an electric motor adapted to move a pusher against a stack of disks to apply a braking force to the stack of disks, selectively, the method comprising the step of causing the actuator to operate in a given operating domain in the current/speed plane in such a manner that the operating domain is selected to present a boundary having a portion that extends substantially along a constant power curve plotted in the current/speed plane.

Abstract: The invention relates to a device for selectively connecting a tire to a pneumatic unit of an aircraft, the tire forming part of a wheel mounted to rotate on a hollow axle of the aircraft, the device comprising a stator and a rotor that is mounted to rotate relative to the stator and that includes means enabling it to be rotated by the wheel. According to the invention, the stator is bell-shaped and is designed to be received as a push-fit in the axle, and includes an end wall carrying a first pneumatic port for connection to the pneumatic unit via a tube running along the inside of the axle, the rotor extending substantially inside the stator.

Abstract: Method for producing a fibrous preform, especially by needling a fiber material (e.g., discontinuous pitch-based or PAN-based fiber). A needle-penetrable mold plate (10) having at least one mold cavity (12) therein for receiving the fiber material is provided. The use of a needle-penetrable mold plate allows the mold plate having the fiber material therein to be passed freely through a linear needling device, such as a linear needling loom, without having to take rigorous care to limit a needling path to the discontinuous fiber material, as in the conventional art. The mold plate is moved relative to the needling device one or more times until a desired level of material density (sometimes measured by fiber content percentage) is attained.

Abstract: The present invention provides a lock sensor for use in an actuator such as is used in aircraft landing gear systems. The lock sensor comprises at least one field emitting device (46) mounted on a locking actuator pressure vessel where the field emitting device (46) monitors the position of at least one target (48). The field emitting device (46) emits a field that when breached by the target sends a signal to indicate that the actuator is in a locked state.

Abstract: A method and apparatus are disclosed for improving densification of porous substrate using a film boiling process. In particular, the disclosed method and apparatus permit more complete densification of a substrate (i.e., densification closer to the surface of the substrate) by providing a sort of barrier that reduces cooling of the surface of the substrate being densified caused by contact with the relatively cool boiling liquid precursor of the densifying material, such as carbon. In particular, contact between the substrate and the liquid precursor is reduced using one or both of physical barriers (such as a mesh material) or structures that promote the formation of an insulating gaseous layer between the substrate and the liquid precursor (such as a plate closely spaced apart from the surface of the porous substrate).

Abstract: The invention relates to a wind-brace device for an aircraft undercarriage, the device comprising a hinged brace movable between a folded position and a stabilization position for stabilizing the undercarriage in the deployed position, a stabilizer member for stabilizing the brace comprising two hinged-together arms, one of the arms having one end hinged to the brace about a hinge axis, and a spring member for urging the arm of the stabilizer member towards the locked position. The spring member is connected to a lever hinged to the brace, the lever presenting a slot in which there is engaged a finger secured to the arm that is hinged to the brace.

Abstract: A semi-levered landing gear for an aircraft comprises a main shock absorber strut (1) connected to the airframe; a bogie beam (4) extending fore and aft of the airframe with forward and aft wheels (J, T) and a main pivot connection (5) to the strut (1) between the forward and aft wheels (7, T) and an auxiliary actuator (49) connected between the strut (1) and the front of the bogie beam (4) at an auxiliary pivot (14). The auxiliary actuator (49) comprises a two stage telescopic hydraulic unit comprising a first stage piston and cylinder actuator (59, 63) and a second stage piston and cylinder actuator (56, 50) operating coaxially within an outer casing (50). A respective piston rod (65, 60) each extends from each end of the casing (50) and is connected to a respective one of said (strut 1) and bogie beam (4). The first stage actuator (59, 63) is operable to an extended position, and the second stage actuator (56, 60) is operable between a retracted position (FIG. 11) and an extended position (FIG.

Abstract: The present invention describes a method of CVI densification in which particular arrangements and mixtures of undensified porous substrates and partially densified porous substrates are arranged in particular ways in order to use the thermal characteristics of the partially densified porous substrates to better distribute heat throughout a CVI furnace and thereby improve densification.

Abstract: Method and device for determining the weight and/or a characteristic value of the position of the center of gravity of an aircraft standing on the ground by means of a plurality of undercarriages, each undercarriage including at least one structural element exhibiting a variable level of stresses depending on the fraction of the weight of the aircraft transmitted to the ground through the undercarriage. The method includes the steps of a) measuring on each undercarriage at least one parameter representing the stress level of the element; and b) evaluating the characteristic value and/or the weight according to the parameters measured in step a). At least one parameter measured in step a) is a magnetic or electrical characteristic of the structural element of the undercarriage.

Abstract: The invention relates to a method of controlling a vehicle brake that is adapted to exert a braking force in response to an actuation setpoint, the method comprising the following steps: from a braking setpoint, determining a nominal actuation setpoint for the brake actuator, taking account of all of the components of the braking setpoint; from the same braking setpoint, and from a measurement of the torque developed by the brake, determining a correction for the nominal actuation setpoint, this correction taking account only of low-frequency variations in the braking setpoint; and adding the correction to the nominal setpoint.