Eurocopter

David Ferullo

Claude Bietenhader

A drag damper for use on a rotary-wing aircraft rotor comprises a body defining two variable volume chambers linked by a piston. The chambers filled with fluid in the damper are connected by a restrictor port in the piston or between the latter and the body, and via a channel of great length and small cross-section compared with the cross-section of the body, in which elastic means bear against and load the piston-rod assembly towards a neutral position, the anti-resonance frequency of the damper being matched substantially to the nominal rotation frequency of the rotor, and the restrictor port providing effective damping at the natural frequency (&#x3c9;&#x3b4;) of the blades in drag, differing by construction from the rotor frequency (&#x3a9;).

Fluid inertia drag damper for rotary wing aircraft rotor

The anti-vibration suspension device comprises at least three oblique bars, each articulated on the gearbox and on the structure by means of a rigid lever supporting an oscillating weight and in turn pivotally mounted by means of at least one pivot on this structure, and each lever is also joined to the gearbox by means of at least one torsion spring biassed about a torsion axis substantially perpendicular to the radial plane defined by the axes of the rotor and the corresponding oblique bar.

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Saint Mitre les Remparts, France

David Ferullo