Cabin interior panel system for reducing noise transmission in an aircraft

A helicopter aircraft comprising:

• a primary airframe structure, the airframe structure defining a cabin section with beams extending at least partially along the top, the beams supporting a helicopter transmission and rotor system;
• a floor located within the cabin section and attaching to the airframe structure;
• a shell structure located within the cabin section and spaced inward from the airframe structure and above the cabin floor, the shell structure including
• a plurality of axially spaced bell frames, each bell frames having a ceiling portion with depending sides portions;
• at least four longitudinal support members attached to and extending between adjacent bell frames;
• a plurality of panels mounted to the shell structure, the edges of adjacent panels forming a butt joint so that each panel is independently removable from the shell structure;
• and
• a plurality of isolators disposed between the shell structure and the airframe structure, each isolator having an first component mounted to a lower end of a bell frame, and a second component mounted on the airframe structure, the second component adapted to mate with the first component, the isolator operative for attaching the shell structure to the airframe structure and for attenuating vibratory transmissions from the airframe structure to the bell frame, the isolators being located distant from the helicopter transmission and rotor system so as to minimize transmission of vibration and noise.

A cabin interior assembly for an aircraft having a primary airframe structure which supports vibrating components located near the top of the aircraft structure, the cabin interior assembly comprising:

• a shell structure located within and spaced apart from the airframe structure, the shell structure providing a rigid structural space frame, the shell structure including
• a plurality of axially spaced bell frames, each bell frames having integral ceiling and side portions forming an inverted substantially U-shaped frame, and
• a plurality of longitudinal support members extending between and attaching to adjacent bell frames;
• a plurality of panels removably mounted to the shell structure, the edges of adjacent panels forming a butt joint so that each panel is independently removable from the shell structure;
• and
• a plurality of isolators disposed between the shell structure and the airframe structure, each isolator having a first component mounted to a lower end of a bell frame, and a second component mounted on the airframe structure, the first and second component adapted to mate with one another for mounting the shell structure to the airframe structure, the isolator operative for reducing vibratory transmission from the airframe structure to the shell structure, the isolators being located distant from the vibrating components so as to minimize transmission of vibration and noise.