System for damping lead-lag motion of rotor blades of helicopter

摘要

A helicopter rotor blade supported by a flexbeam to be rotatable about an axis of rotation, in which a pitching motion thereof is allowable, is provided with a device for changing the pitch and damping the lead-lag motion thereof. The device comprises a bushing in a through hole formed at the inboard end of the flexbeam, an elastomeric pivot loosely fitted in the bushing, elastomeric dampers of cylindrical shape mounted on the upper and lower surfaces of the flexbeam and coupled with the upper and lower ends of the elastomeric pivot by means of nuts, and torque arms extending through the bushing and the elastomeric dampers and having the central portion thereof connected to central shafts of the elastomeric pivots. Each of the torque arms has both ends outwardly projecting beyond the elastomeric dampers and secured to a pitch sleeve which encloses the flexbeam. Therefore,the relative position between the pitch sleeve and the elastomeric pivot does not change even when lead-lag motion is imparted to the rotor blade.