Abstract: It is described a method for reconditioning a damaged thread (8) of a transmission (1) of a hover-capable aircraft; the damaged thread (8) being arranged inside a first hole (23a) of the transmission (1); wherein the method includes the following steps: i) centering a tool (20) on the first hole (23a); ii) inserting a first tool (25) inside the tool (20) centred on the first hole (23a) and removing the damaged thread (8) through the first tool (25); iii) inserting a second tool (26) inside the tool (20) and creating a new thread (16) inside the first hole (23a) having a diameter larger than the one of the damaged thread (8); iv) screwing an insert (61) having a thread inside the new thread (16), so that the insert (61) engages the first hole (23a) and defines a reconditioned thread (8?); and v) keeping the transmission (1) mounted on the hover-capable aircraft during steps i), ii), iii), iv).

Abstract: A rotor for an aircraft is described that comprises: a hub rotatable about an axis and, in turn, comprising a plurality of blades; a mast connectable to a drive member of the aircraft and connected to the hub to drive the hub in rotation about the axis; and damping means to dampen the transmission of vibrations to the mast in a plane orthogonal to the axis; the damping means comprising at least a first mass and a second mass that can eccentrically rotate about the axis with a first and a second speed of rotation, respectively; the first mass and second mass are operatively connected to the mast to generate, respectively, a first and a second damping force on the mast having a main component in a direction radial to the axis; the rotor comprises a transmission unit, which is interposed between the mast and the first and second masses so as to drive the first and second masses in rotation.

Abstract: It is described a method for reconditioning a damaged thread of a transmission of a hover-capable aircraft; the damaged thread being arranged inside a first hole of the transmission; wherein the method includes the following steps: i) centering a tool on the first hole; ii) inserting a first tool inside the tool centred on the first hole and removing the damaged thread through the first tool; iii) inserting a second tool inside the tool and creating a new thread inside the first hole having a diameter larger than the one of the damaged thread; iv) screwing an insert having a thread inside the new thread, so that the insert engages the first hole and defines a reconditioned thread; and v) keeping the transmission mounted on the hover-capable aircraft during steps i), ii), iii), iv).

Abstract: A rotor for an aircraft is described that comprises: a hub rotatable about an axis and, in turn, comprising a plurality of blades; a mast connectable to a drive member of the aircraft and connected to the hub to drive the hub in rotation about the axis; and damping means to dampen the transmission of vibrations to the mast in a plane orthogonal to the axis; the damping means comprising at least a first mass and a second mass that can eccentrically rotate about the axis with a first and a second speed of rotation, respectively; the first mass and second mass are operatively connected to the mast to generate, respectively, a first and a second damping force on the mast having a main component in a direction radial to the axis; the rotor comprises a transmission unit, which is interposed between the mast and the first and second masses so as to drive the first and second masses in rotation.

Abstract: A sealing ring for a seal assembly is described that comprises: a main body rotating about an axis; and a first surface, which is defined by the main body, extends transversely to the axis and is suitable for abutting against a further sealing ring in a direction parallel to the axis; the first surface comprises a plurality of grooves forming respective hydropads; the grooves are delimited by a first edge and a second edge facing one another; the first edge and the second edge delimit the grooves in a circumferential direction to said axis; at least one of the first edge and the second edge is shaped like an elliptical arc, which has coincident or separate foci; comprises first grooves and second grooves alternating with one another in a circumferential direction to said axis and staggered from each other in a radial direction to said axis.

Abstract: A sealing ring for a seal assembly is described that comprises: a main body rotating about an axis; and a first surface, which is defined by the main body, extends transversely to the axis and is suitable for abutting against a further sealing ring in a direction parallel to the axis; the first surface comprises a plurality of grooves forming respective hydropads; the grooves are delimited by a first edge and a second edge facing one another; the first edge and the second edge delimit the grooves in a circumferential direction to said axis; at least one of the first edge and the second edge is shaped like an elliptical arc, which has coincident or separate foci; comprises first grooves and second grooves alternating with one another in a circumferential direction to said axis and staggered from each other in a radial direction to said axis.

Abstract: A lock ring for securing a threaded stud to a first member, the ring having a first surface defining the ring on the side facing a first axis of symmetry of the ring, and in which a toothed impression is formed when it is forced onto a toothed portion of the threaded stud; and a conical second surface defining the ring on the opposite side to the first axis, and which is forced inside the first member.

Abstract: A fastening assembly having a tubular first coupling member; a second coupling member insertable coaxially inside the first coupling member in a first direction; and releasable fastening means for locking the first and second coupling member to each other in a predetermined axial lock position. The fastening means include: first and second engaging means formed on the first and second coupling member, connectable to each other to define a foolproof angular insertion/release position, and releasable by positioning the second coupling member in a predetermined axial position inside the first coupling member; and third and fourth engaging means formed on the first and second coupling member and connectable to each other in a further angular position of the second coupling member, different from the angular insertion/release position, by moving the second coupling member axially, from the predetermined axial position, in a second direction opposite the first direction.

Abstract: An epicyclic gear train, for an aircraft capable of hovering, having a sun gear rotating about a first axis; a fixed ring gear positioned coaxially with the first axis and radially outwards with respect to the sun gear; a number of planet gears, which are interposed between and mesh with the sun gear and the ring gear, and rotate about respective second axes, in turn revolving about the first axis; and lubricant feed means; the feed means having a number of nozzles arranged about the first axis and the sun gear to produce an annular flow of lubricant.

Abstract: A fastening assembly having a longitudinal axis; a tubular first coupling member; a second coupling member insertable coaxially inside the first coupling member in a first direction; and releasable fastening means for locking the first and second coupling member to each other in a predetermined axial lock position. The fastening means include first and second engaging means formed on the first and second coupling member, connectable to each other to define a foolproof angular insertion/release position, and releasable by positioning the second coupling member in a predetermined axial position inside the first coupling member; and third and fourth engaging means formed on the first and second coupling member and connectable to each other in a further angular position of the second coupling member, different from the angular insertion/release position, by moving the second coupling member axially, from the predetermined axial position, in a second direction opposite the first direction.

Abstract: A lubricating pump having a first stage and a second stage; the first stage in turn has an intake connectable hydraulically to a tank of lubricating fluid, and a delivery outlet connectable hydraulically to a lubricated member; the first stage compresses the lubricating fluid from the tank to a pressure for supply to the member; the second stage in turn has an inlet connectable hydraulically to a casing housing the member, and an outlet connectable hydraulically to the tank; the second stage feeds the lubricating fluid in the casing back into the tank; the second stage is a Roots type, and has a first and a second rotor rotating about respective axes to feed the lubricating fluid from the inlet to the outlet; and the first and second rotor are operated by the first stage.

Abstract: A lubricating pump having a first stage and a second stage; the first stage in turn has an intake connectable hydraulically to a tank of lubricating fluid, and a delivery outlet connectable hydraulically to a lubricated member; the first stage compresses the lubricating fluid from the tank to a pressure for supply to the member; the second stage in turn has an inlet connectable hydraulically to a casing housing the member, and an outlet connectable hydraulically to the tank; the second stage feeds the lubricating fluid in the casing back into the tank; the second stage is a Roots type, and has a first and a second rotor rotating about respective axes to feed the lubricating fluid from the inlet to the outlet; and the first and second rotor are operated by the first stage.

Abstract: A method for determining a position of a rotor of a synchronous alternating-current permanent-magnet machine includes injecting a high-frequency voltage superimposed on a voltage delivered by a machine control system; measuring a current of the motor and extracting a current corresponding to the injected voltage; and obtaining, from the injected voltage and from the corresponding current, an electrical angle &thgr; suitable to identify the position of the rotor by using a sine and cosine of twice the electrical angle &thgr; of the machine.

Abstract: A method for determining the position of the rotor of a synchronous alternating-current permanent-magnet machine, its particularity consisting of the fact that it comprises the steps that consist in: