The necessity for realizing a major reduction in community noise from that produced by the current air transport fleet was recognized at the inception of the design of the Lockheed L-1011 Trijet wide-bodied transport. This paper summarizes the technical considerations and design procedures used to ensure attainment of the low-noise objective.
It is shown that the Rolls-Royce RB.211 engine selected for the L-1011 incorporates the latest state of the art noise reduction features, including the novel shaft-slowing provision. These features result in a significant reduction in basic noise level compared to low by-pass ratio engines currently in service, even at the considerably increased size required for the L-1011. The additional noise reduction required to satisfy the low community noise objective and the FAR Part 36 limits is attained by incorporation of advanced noise suppression materials into an efficient propulsion pod design. The technology, design restraints, and system requirements which must be combined into the practical optimum minimum noise pod design are described.