Abstract: Helicopter rotor on which each blade is connected in articulated manner to a center hub by means of a forkthe vertical plane movement of which, at rotor speeds below a given set value, is limited by a pair of limit rocker arms located between the hub and a ring nut mounted in rotary manner on the forkand rendered angularly integral with the hub by means of a compass drive.

Abstract: There is disclosed a longitudinal member for a helicopter blade made by placing inside an open mold an open outer covering on which covering and in contact with are arranged a number of uncured axial straps which define top and bottom backs of the longitudinal member itself; the straps being compacted, prior to closure of the mold, against a center core and a front nose by inserting a rear element made of prehardened synthetic composite material, the rear element having an essentially C-shaped section and the opposite side edges of the outer covering being folded thereover prior to closure of the mold.

Abstract: Helicopter rotor on which a number of blades are each connected to a perimetrical bridge element on a hub by means of a fork element extending round the said bridge element and connected to it by means of two elastomer supports, arranged in series, of which one is designed to dampen at least operation of the blade in the hub plane.

Abstract: A rotor for helicopters, in which a central hub supports a plurality of radial blades connected thereto, each of which blade is provided with a surface rigidly connected to it and able to cooperate with respective abutment elements supported by the hub and movable with respect to this latter in a substantially horizontal plane to limit the oscillations of the respective blade in a horizontal plane between limits which are variable as a direct function of the angular velocity of the rotor itself.

Abstract: Helicopter rotor on which the blades are each connected to a center hub plate by means of a U-shaped fork connected to the hub by an elastomer support, the latter supporting a static supporting device for limiting dynamic oscillation on the relative blade in the vertical plane, the said device providing for use of a pin faceted on the side, mounted so as to turn on a taper seat integral with the relative fork and designed to engage with a mating surface integral with the hub.

Abstract: Helicopter rotor on which static balancing of the rotor is provided for by a number of annular-shaped counterweights housed inside each pin securing each blade to the hub; the said counterweights being supported by a rod pressed an clicked inside an axial hole on the relative pin.

Abstract: A device for controlling the cyclic and collective pitch of a helicopter rotor in which a fixed ring of an oscillating plate is maintained regularly fixed and is guided in its oscillations with respect to a drive shaft by a plurality of variable configuration supports uniformly distributed about the said drive shaft and connected to the said fixed ring by means of cylindrical pivots at least one of which is eccentric with respect to an axis rotation of an associated supported fork, which is perpendicular thereto.

Abstract: A helicopter rotor hub having a lobed shape defining a plurality of bridge structures each allowing the attachment of a respective blade; each bridge structure is formed of superimposed sections of three annular bands, of synthetic material, the intermediate one of which forms an outer frame extending around the whole of the periphery of the hub, while the other two define one of the said lobes and connect the said outer frame to an inner metal structure.

Abstract: A helicopter rotor in which a central plate-like hub is provided with a plurality of axial apertures uniformly distributed around a central axis of rotation and each defined radially outwardly by a supporting peripheral bridge connected to a respective blade by a U-shape structure extending through the said aperture and coupled to the associated bridge by an elastomeric coupling; each U-shape structure being coupled to a respective radial projection of the hub by a further elastomeric coupling.

Abstract: FH (FLEX-HUB) helicopter rotor on which each blade is connected to a center hub by a fork having two arms on one side for connection to the relative blade and integral, on the other, to a rod connected to the hub by an elastomer support; the forks being interconnected by a polygonal ring passing between the said arms on each fork and each side of the said ring being supported centrally by a flexible arm extending radially from the hub.

Abstract: A countertorque rotor for helicopters in which a transmission shaft keyed transversely onto a drive shaft and disposed obliquely within a hub has each of its ends coupled in a slidable manner within an inner bush of an associated elastomeric coupling this latter carrying screw actuator means which can act axially on the said shaft to displace the said hub with respect to the shaft (3) itself in the direction of the axis of this latter.

Abstract: A composite hub for a helicopter rotor, the hub having the form of a flat plate of laminated structure provided with a plurality of through holes each able to house an elastomeric coupling for connection of an associated blade, and a central layer of the said plate being constituted by a force distributor element in contact with each surface of which there is disposed at least one layer constituted by radial elements extending outwardly of an axis of rotation of the hub and an annular element disposed in contact with the free ends of the said radial elements; these latter being connected to the radial elements disposed on the other side of the distributor element by means of axial elements (25) defining part of the surface of the said aperture.

Abstract: A method for making helicopter blade spars in which a tape of reinforced resin is laid up with a continuous circulatory movement along an annular path defined by a lateral surface of a former of a forming mould in such a way as to define an annular body constituted by two ribs of the spar, rigidly connected together and opposite one another; each rib being subsequently separated from the other by cutting the said annular body.

Abstract: A rotor shaft for helicopters in which a main rotatable shaft is tubular and supports in its interior a shaft (25) which is angularly fixed relative to the helicopter body and disposed coaxially to said main shaft; a swivel plate assembly being coupled to said fixed inner shaft and being disposed, together with at least part of a plurality of kinematic linkages connecting said swivel plate to the rotor blades and a plurality of actuator means controlling the position of said swivel plate, inside the space lying between said main shaft and said inner shaft.

Abstract: A helicopter rotor comprising elastomer joints, in which each blade is connected to a rotatable hub by means of a yoke constituted by a single U-shaped piece and mounted through a relative aperture provided in said hub;each yoke being connected to a transverse arm outwardly bordering said aperture, by means of a U stirrupembracing the relative said arm and provided with two overlying appendices extending outwards and having two surfaces inclined towards the other and acting as stop surfaces for two rocker arms constituting a devicefor controlling the flapping movements of said blade; said two rocker arms being mounted rotatable in a substantially vertical plane passing through the axis of the relative blade and being supported by a lever for controlling the pitch of this latter.

Abstract: The multi-blade articulated rotor for helicopters, comprises a hub connected to a shaft rotatable substantially about a vertical axis, the hub being in the form of a plate comprising a plurality of perforations, each of which defines a bridge of material of said plate between a part of the edge of said perforation and a part of the edge of said plate; a plurality of yokes, each of which is substantially of U shape and comprises a pair of substantially parallel arms and a base element which connects together one end of said arms, the other end of the arms being connected to one of said blades, said base element being inserted into one of said perforations in the hub; a plurality of elastomer bearings, each of which is disposed between said base element of a yoke and the corresponding hub bridge; and means for limiting the amplitude of the swivel movement which each of said yokes can make substantially in a vertical plane.

Abstract: An electron microscope including a base, a frame supported by said base, a vacuum chamber supported by said frame and including a fixed cup-shaped member having a lateral aperture closed by a movable cover, the latter including a further interchangeable cup-shaped member with its concavity facing said aperture, and supported by substantially horizontal guide means rigid with said frame for moving from and towards said fixed cup-shaped member; support means being provided inside said further cup-shaped member for supporting a piece holder in an adjustable position.

Abstract: A method for mounting pieces inside the vacuum chamber of an electron microscope, said chamber including a fixed cup-shaped body laterally closed by a mobile closure element supporting a piece holder, and detection means disposed inside said chamber; the method providing for provision of a transparent rigid mask which reproduces the shape of said chamber and said detection means, and is to be arranged in contact with said closure element before closing it to adjust the position of the piece to be observed.

Abstract: A helicopter rotor hub is provided with a center plate and a plurality of arms projecting from the center plate. Each of the projecting arms has a slot for receiving a flexible element that is connected to a spindle and grip that supports the rotor blades. The rotor blades can accomplish the movements of flapping and lag by allowing the center plate to have a low stiffness in the vertical plane when the center plate lies in a horizontal plane, and the flexible element a low stiffness in the horizontal plane when the flexible elements lie in the vertical plane, thereby acting as virtual hinges. This allows for the possibility of locating the vertical hinges at an equal distance from the rotor axis, and the pitch variation hinge a small distance from the other hinges, allowing for a relatively small dimension of the hub.