Abstract: The wings of a rotary wing aircraft comprise, for example, four wing blades orming two pairs of wing blades whereby the blades of a pair are located diametrically opposite each other. The blades of a pair are connected to each other by a spar extending from wing blade to wing blade. The spar is operatively secured to the rotor head. Each spar has between the rotor head and the respective wing blade a zone with a torsion yieldability larger than in the spar outside said zone. A beam stiff against bending, bridges the zone, referred to as a torque soft zone, from the wing blade toward the rotor head except for a small flexible section between the rotor head and the radially inner end of the beam. The flexible section permits the blade flapping movements and the blade lead-lag movements.

Abstract: A rotor blade is connected to a rotor hub, for example, in a helicopter, by t least one pair of damping elements and by a blade connector bolt. The damping elements comprise metal discs and layers of elastomeric material arranged in sandwich fashion. The damping elements are arranged symmetrically relative to the rotor blade, as well as to the blade connector bolt. Furthermore, the damping elements are connected in a force transmitting manner to the rotor blade on the one hand and to the rotor hub on the other hand.

Abstract: One of two races of a roller bearing is equipped with a sliding ring exteng thereabout, with a melting ring formed of material having a melting point higher than the normal operating temperature of the bearing being interposed between the one race and the sliding ring. Malfunction of the bearing such as might occur by seizure of the bearing rollers will cause at least partial melting of the melting ring whereupon the one race is placed in relative sliding engagement through the melting ring with the sliding ring.