Abstract: Gadolinium- or boron-doped drilling mud is used during drilling so that it will penetrate all natural cracks in the formation that intersect with the wellbore. Once cased, cemented and washed, the doped mud will only be in the fractures. Pulsed neutron logging is performed, and natural factures thereby characterized.

Abstract: Gadolinium- or boron-doped drilling mud is used during drilling so that it will penetrate all natural cracks in the formation that intersect with the wellbore. Once cased, cemented and washed, the doped mud will only be in the fractures. Pulsed neutron logging is performed, and natural factures thereby characterized.

Abstract: The anti-vibration suspension device comprises at least three oblique bars pivotably mounted each on the gearbox and on the structure, by means of a rigid lever supporting a vibrating weight and in turn pivotably mounted on this structure, and each lever is also linked to the structure by at least one torsion spring biased about a torsion axis substantially perpendicular to the radial plane defined by the axes of the rotor and the corresponding oblique bar.

Abstract: Each blade of the rotor has a rigid root oversleeve connected to a torsionable and flexible root strip by two laminated, spherical support half bearings, fixed by their outer frame with double rigid horns the lateral ends of which facing each other on each side of the strip and half bearings are clamped towards each other and against struts so as to allow a significant, calibrated pre-compression of the half bearings. The double horns and/or struts are fixed axially to the oversleeves by fixing elements distinct from the compression means of the double horns on the struts and perpendicular to these compression horns on the struts and perpendicular to these compression elements. One of the struts, possibly in a single piece with one double horn, is also in a single piece with a pitch lever.

Abstract: Suspension means for mechanical elements which have a plate rigid with an element which is to be suspended. The rigid plate is connected to fixed mountings by flexible studs working in compression and by a deformable articulated system composed of connecting rods and a floating cross-member, ensuring rotationally rigid connection and providing for absorption of a torque originating from the suspended element, while allowing the element to perform translatory movements.

Abstract: The invention relates to a rotor, specially for a gyroplane. The rotor comprises elongated connecting members respectively inserted between the rotor hub and the rotor blades. Each connecting member comprises a bundle of fibres having a high mechanical strength and agglomerated by a vulcanized elastomer at least in the mid part of the fibre bundle. A rigid tubular sleeve extends in a spaced and surrounding relationship to each elongated connecting member. Each tubular sleeve has an outer end connected to the root part of the respective blade and an inner end with a lateral lug articulated to the blade pitch control lever. An annular elastomer member is inserted in the annular space between the inner end of each tubular sleeve and the corresponding end of the respective connecting member.