Abstract: A piston ring for the piston of an internal combustion engine, comprising, on a lower side of the piston ring, a circular, radially inner bezel, the width thereof reducing, on both sides of the ring stop, up to the side of the piston ring that is opposite the ring stop, in a symmetrical manner in relation to a radially situated axis and runs through the ring stop, and the bezel on the lower side of the piston ring is arranged away from the piston base. A good oil-scraping effect of the piston ring is obtained over the entire periphery of the inner wall of the cylinder.

Abstract: The invention relates to a piston ring (1) for the piston of an internal combustion engine, comprising a circular, radially inner bezel (2), the width thereof reducing, on both sides of the ring stop (3), up to the side (4) of the piston ring (1) that is opposite the ring stop (3), in a symmetrical manner in relation to a radially situated axis (8) and runs through the ring stop (3), and the bezel on the lower side of the piston ring (1) is arranged away from the piston base. A good oil-scraping effect of the piston ring (1) is obtained over the entire periphery of the inner wall of the cylinder.

Abstract: By means of this acoustic protection it is possible to protect the payloads of expandable launch vehicles effectively against noise emissions from the rocket propulsion system which result in damage of the payloads. For this purpose acoustic absorbers (8) tuned to a defined frequency range are provided and are arranged in foamed plastic mats (7) disposed on the insides (6) of the payload fairing (1). The acoustic absorbers (8) are composed of a cup-shaped lower part (12) and an upper part (13) having a horn (18). The horn (8) tapers in a curved-conical manner from a larger diameter (D.sub.m) to a smaller diameter (D.sub.t) and projects into the lower part (12) by a defined distance (a) from a bottom (14) thereof. Slits (21) for the dissipation of the directed flow energy occurring in the horn (18) are disposed in the wall of the horn in the area of the smaller diameter (D.sub.t).