Abstract: The invention relates to an articulated rotor head for gyroplanes comprising a rigid central hub body (1), perpendicularly integrated with a drive shaft (2), each blade (3) being radially fixed to the hub body (1) by means of connecting and articulating components. These components each comprise:a spherical laminated elastomer stop (4) housed in the central hub body;a hollow sleeve (5) rigidly locked to the spherical laminated stop (4);an elastic return and drag damping brace (9) of the blade (3) arranged between the sleeve and the outer part of the rigid hub body (1) on a contiguous sleeve;a connecting and pitch articulation spindle (6) of the blade (3) connected to the foot of the blade (3) and a pitch lever (8) rigidly locked to the spindle (6) and which swivels about the pitch axis inside the sleeve (5) on two bearings, one of which at least forms a thrust stop (7) to transmit, from the spindle (6) in the sleeve (5), the thrust loads originating from the centrifugal forces on the blade (3).

Abstract: Gyrocraft rotor hub body (1) in which each blade (2) is linked to the body (1) by articulations and linking members the body includes two strong elements (7, 8) whose planes are substantially parallel to each other and perpendicular to the axis of the mast (3) of the rotor. The two elements (7, 8) are separated from each other by a space which is of sufficient size to permit the housing of the articulations which are advantageously embodied in the form of laminated spherical stops (5), one of the armatures (16) of which moves integrally with the (17) is fixed with respect to the two elements of the hub body and is arranged in the vicinity of the periphery of these elements so as to constitute a rigid bracing.

Abstract: Method and device for the reduction of the oscillations of a divergent nature induced in the fuselage (2) of a helicopter (1) by its rotary wings (3) when they are turning. According to the invention, the oscillations are detected (at 17, 18) and they are converted (at 19, 20) into electrical signals, which are used (at 13) in order to produce pitch variations of the blades (4) of the rotary wings (3), in such a way that a rotating torque vector opposing said oscillations results.

Abstract: Gyrocraft rotor head including a hub connected to each blade (2) of the rotor by a linking member which is integral with the blade (2) and which is linked to the hub body by a laminated spherical stop. Each blade (2) is fitted with an assembly (20) for elastic recall in drag with incorporated damping, one of whose extremities (22) is linked to the member linking the blade to the hub body. The linking member is constituted by an intermediate sleeve (11) comprising one part in the form of a ring (12) and one part fitted with at least one double clevis (14), the intermediate sleeve (11) being a single integral assembly of which the ring (12) surrounds the laminated spherical stop with which it is integrated and of which the double clevis or clevises interact with the structure for integration of the blade (2).

Abstract: A device for elastic coupling between two parts, especially the principal transmission box and the fuselage of an aircraft with rotating wings, such as a helicopter, includes first and second inner and outer tubular bodies, and an elastic connection, housed in the annular space existing between the first and second bodies and coupling the first and second bodies in a leaktight fashion. The annular space is separated by the elastic connection into first and second chambers filled with a liquid, the first and second chambers being in communication with the inside of the first body. On the inside of said first body, there is a liquid distributor provided with an elastic damping connection and including two pistons, which are coupled by a piston rod and separated from each other by the distance separating orifices in the first and second chambers.

Abstract: The invention relates to a flapping restrainer device for the blades of a rotorcraft main rotor, and a rotor head comprising the same. The lower restrainers comprise a reciprocal star-shaped plate (32), having as many radial branches (33) as blades, and each one of the branches being engaged into a radial opening (6) of the hub (3). Outside the latter, the star-shaped plate (32) cooperates with supporting runners (47) integral with the blades. The upper restrainers comprise, for each blade, a stop which is retractable by the effect of the centrifugal force and which is composed of a lever (52), pivoting on a pivot (53) carried by the hub (3), and a first arm (55) of which constitutes a stop finger directed towards an upper supporting component (60) integral with the blade, while a second arm (56) carries a governor weight (57) and a nose (58) for support against a shoulder (59) integral with the hub (3).

Abstract: In a main transmission gearbox for a helicopter having two engines, a lifting rotor and an anti-torque rotor, each of the two engines drives a main kinematic chain comprising from upstream down, an input shaft, a twistable shaft, a gear train forming a first reduction stage having a first bevel pinion meshing with a second bevel pinion which drives in rotation a vertical shaft bearing having a third pinion in mesh with a gearwheel which is common to the two main chains and forms with the third pinions a second reduction stage. The torque received at the gearwheel is transmitted to the driving shaft of the main rotor by way of a supplementary reduction stage of epicyclic type. A third chain comprising two input pinions each of which is mounted upon one of the input shafts and an intermediate pinion which drives the driving shaft of the anti-torque rotor, ensures the distribution of power over the two main chains in the event of breakdown of one engine.

Abstract: A directional and stabilizing device is provided including a faired antitorque rotor, driven in rotation in a transverse aperture formed in a fairing slanted with respect to the vertical by an angle between 0.degree. and 45.degree.. It also includes a "V" empennage fixed to the top of the fairing and the two aerodynamic surfaces of which extend disymmetrically with respect to the vertical plane passing through the top of this fairing, the aerodynamic surfaces being slanted in angular planes between 0.degree. and 45.degree..

Abstract: The invention provides an integrated hub-mast with a single piece tubular body which supports, by its hub body part (3), a reinforcing girdle (6) on each side of which openings (10, 11) are formed. For each blade of the rotor a retaining and pivoting member (13), formed preferably by a spherical stratified stop, is fixed to the girdle (6) and is retained in the hub body (3), and this member (13) is also fixed between the ends inside the hub body (3), of the lower (20) and upper (21) branches of a forked fastening part (19) connecting the blade to this member (13), these branches passing through the openings (10, 11) of a corresponding pair of openings. A heel (23) fixed under the lower branch (20) bears against a reciprocal ring (24) mounted on a support (29) in the hub-mast (1), which has external fastenings for coupling to resilient return and drag damping members of the blades.

Abstract: The integrated hub-mast (1) of the invention is composed of a tubular single piece body whose hub body forming part (3) is integral, on the side of its end end opposite the mast (2), with a reinforcing ring (5) and in which openings (6) are pierced. For each blade of the rotor, a stratified spherical stop (16) is fixed against the ring (5) and is retained in the hub body (3) and this stop (16) is also fixed to the ends integral to the hub body (3) of the lower (24) and upper (25) branches of a forked fastening part (23) connecting the blade (22) to the stop (16), the lower branch (24) passing through an opening (6) in the hub (3). A central flapping stop (30) is mounted on a support (31), in the hub-mast (1), which carries external fastenings for coupling to the resilient drag return and damping members of the blade.

Abstract: A variable pitch multi-blade propeller suitable for use on a helicopter is constructed of a foam preform joined with a fibrous spar enclosed in resin-impregnated foils and fitted with a metal leading edge. Various components are assembled in a mold and the resins, then cured. The structure may further include a reinforcing yoke of carbon fiber fabrics preimpregnated with a polymerizable synthetic resin. The process may further include a heat treating step to effect polymerization.

Abstract: Each blade is fixed to the hub by the root part of the spar, arranged in the form of a loop surrounding a connection element bolted on the hub, with the interposition of rigid rings by a pin simultaneously fixing the hub on a drive sleeve transmitting thereto the driving torque of the central shaft. The hub comprises two coaxial cylindrical walls in each of which is pierced, for each blade, a circular opening in which the member for controlling the angle of attack which is fast with the blade root is mounted to rotate via self-lubricating rings. The invention is particularly applicable to helicopters.

Abstract: Each blade is fixed to the hub by the root part of the spar, arranged in the form of a loop surrounding a connection element bolted on the hub, with the interposition of rigid rings by a pin simultaneously fixing the hub on a drive sleeve transmitting thereto the driving torque of the central shaft. The hub comprises two coaxial cylindrical walls in each of which is pierced, for each blade, a circular opening in which the member for controlling the angle of attach which is fast with the blade root is mounted to rotate via self-lubricating rings. The invention is particularly applicable to helicopters.

Abstract: A hub plate and helicopter rotor incorporating same made of a composite material and comprising a laminated disc constituted by layers of fiber cloth having high mechanical strength. A frame of the disc is made of aligned layers of the cloth with the weft or warp of the cloth extending radially in the direction corresponding to the direction of centrifugal force acting on the plate when in use. The aligned layers are positioned at the core of the structure and at least at the surface of the structure in the peripheral portion of the disc. The disc is enclosed by a belt of parallel threads consisting of fibers having high mechanical strength fitted on radially outwardly projecting parts of the disc in recesses formed in the outer edge of the parts, the recesses being open to the exterior.

Abstract: The invention concerns a helicopter rotor, the rigid hub (1) of which comprises a central drum (2) which is disposed substantially in line with the rotor mast (3) and which carries an upper plate (4) and a lower plate (6). This rigid hub (1) is connected to the root of each blade (26) by way of a laminated spherical stop (13) and a resilient-return drag brace. Each blade (26) comprises, in the zone of its root, a rigid loop (27) which surrounds the laminated spherical stop (13) in a continuous manner and is engaged in the inner movable fitting (24) of this stop (13) by means of a wedge (30) co-operating with the outer fixed fitting (15) of the stop (13).

Abstract: The invention relates to a suspension device for the main transmission box of a helicopter, comprising two flexible bars which are fixed centrally at the bottom of the transmission box and are supported by articulated joints at strong points of the fuselage and which carry swinging weights at their ends. An articulated rod connects the bottom of the transmission box and the fuselage.

Abstract: The invention relates to aeronautics in general, and in particular to a suspension device for helicopter, comprising a flexible mounting plate at the center of which is fixed the bottom of the main gear box whose top is supported by hinged oblique bars. The mounting plate offers radial arms hinged to the base of the bars and to the fuselage of the helicopter. These arms bear flapping weights creating forces of inertia with reactions at the attachment points of direction opposite the elastic reactions of deformation of the mounting plate. A device of this type enables the vibrations on board helicopters to be reduced.

Abstract: The subject of the invention is a suspension device for a helicopter, intended for reducing the vibrations caused by its rotor. The main transmission box of the rotor is supported at the top by a set of oblique articulated bars and is bolted at its bottom to a diaphragm made of thin sheet metal, which can be deformed by bending, but not by shearing in its plane. Flexible arms arranged radially and supported by fixed mountings are articulated to the foot of the oblique bars and to the bottom of the transmission box; they each carry, at the end of a lever, a swinging weight acting by the effect of inertia.

Abstract: Rotary-wing aircraft rotor comprising a rigid hub coupled to the root of each blade in which a trailing return brace comprises a stack of metal plates alternating with plates of visco-elastic material the ends of which being coupled via a ball joint respectively to the root of one blade and to a place of the hub such that the brace is always slightly inclined.

Abstract: The present invention relates to a high performance blade for helicopter rotor presenting an aerodynamic surface produced by profiles of which the aerodynamic twist increases from the end profile towards the root profile and is then reversed and becomes zero at the fastenings of the blade. According to the invention, the angle of twist formed by the zero lift chord C.sub.o of a profile of the aerodynamic surface and a reference plane P passing through the center of the fastenings of the blade to the hub of the rotor, is, for the end profile, at the most equal to a value .theta..sub.1 of 0.3 degrees. The invention is more particularly applied to the obtaining of rotary wings, for example for helicopters, capable of very high performances, particularly in rapid forward flight under high load.