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Project02

The Ilyushin Il-96-300

The reduction of noise level in the meeting room of the airplane to those complying with the requirements of the first class of long-range aircrafts.

Customer

OOO “Vemina Aviaprestizh”

OOO “Vemina Aviaprestizh”

Historical background:

Il-96 - is a long-haul wide-body airliner. It is the first Russian airplane with an electronic flight control system. It was designed by Ilyushin Design Bureau in the late 1980s, and is manufactured by Voronezh Aircraft Production Association since 1993.

1110x560
290x290

Problem

The noise level in a meeting room and the cabin in general exceeds the allowable noise level.

Tasks

  • 01

    To analyze vibro-acoustic characteristics of Il-96

  • 02

    To search for the weak points and to localize the sources of noise and the ways of noise penetration into the meeting room.

  • 03

    Development of an engineering solution and obtaining an approval from Ilyushin Design Bureau and Voronezh Aircraft Production Association.

  • 04

    Production of an acoustic kit for noise level reduction, and its installation.

Research

  • We conducted the initial tests while in flight at the course speed in order to define the real noise level values in different zones of the airplane: the VIP passenger seat, the meeting room, the compartment area, the first class and the economy class
  • We detected the ways of noise penetration into the meeting room, vibration propagation along the interior panels, and acoustic propagation speed in interior panels.

Main noise sources

  • Ceiling
  • Arch panels and interstices under them
  • Floor panels
  • Window panels
  • Interstices in the ceiling

Solutions:

We designed a kit of low-combustible parts fitting the requirements of the Federal Air Transport Agency. The solution meets the flammability requirements and the requirements of acceptable additional load on the interior panels and the body of the aircraft.

  • 01

    To increase sound insulation and optimize sound absorption

    To soundproof the ceiling, arch panels and interstices, we used the material Melaton 2TK.

    To increase sound insulation and optimize sound absorption

    We designed special constructs which allow reducing noise level significantly even in a confined space and with a limited weight.

    To get a solid sound insulating carpet, we stitched an adhesive tape along the edges of the mats, which fastened the sound insulating construct during the flight, take-off, and landing. The use of a multilayer polymer material not only improves the sound insulating properties, but also increases the stiffness of the mat, so it can be used on the body of the aircraft without any complex securing elements.

    Materials used

    • Melaton 2 TK
      Melaton 2 TK

      Sound absorbing material

      More Hide

      A foamed material made from melamine resin with 3D open-cell structure. The material is covered with nonflammable water-resistant fabric.

      Physical and mechanical characteristics of the material:
      Thermal conductivity at a temperature of 25 °С:
      0.036W/mK
      Flammability class:
      Self-extinguishing
      Smoke generation ability (Dt=2; Dt=4; Dmax when burning and smoldering)
      max: 200
      Facing layer-to-foamed layer bond strength:
      0.6 N/cm
      Anti-adhesive film-to-adhesive layer bond strength:
      0.01-0.1 N/cm
  • 02

    To reduce the vibration of panels

    For window panels and arch panels of the meeting room, we designed individual constructs with the materials VDF and Melaton 2TK.

    To reduce the vibration of panels

    Materials used

    • Melaton 2 TK
      Melaton 2 TK

      Sound absorbing material

      More Hide

      A foamed material made from melamine resin with 3D open-cell structure. The material is covered with nonflammable water-resistant fabric.

      Physical and mechanical characteristics of the material:
      Thermal conductivity at a temperature of 25 °С:
      0.036W/mK
      Flammability class:
      Self-extinguishing
      Smoke generation ability (Dt=2; Dt=4; Dmax when burning and smoldering)
      max: 200
      Facing layer-to-foamed layer bond strength:
      0.6 N/cm
      Anti-adhesive film-to-adhesive layer bond strength:
      0.01-0.1 N/cm
    • VDF
      VDF

      Vibration absorbing material

      More Hide

      Multilayer material consisting of embossed aluminium foil and an adhesive polymer layer covered with anti-adhesive paper

      Physical and mechanical characteristics of the material:
      Flammability class:
      Combustible Hardly inflammable
      Sealant-to-painted metal surface bond strength whilst peeling off:
      3.0 N/cm
      Resistance to low temperatures (-60 °С):
      the material doesn’t peel off from the painted metal plate
      Smoke generation coefficient:
      moderate smoke generation ability
  • 03

    For vibration absorption

    To the internal surface of the floor panels, we applied the sealant STP FP.

    For vibration absorption

    Materials used

    • STP FP
      STP FP

      Sealant

      More Hide

      An adhesive polymer layer covered with anti-adhesive paper on both sides.

      Physical and mechanical characteristics of the material:
      Flammability class:
      Hardly inflammable
      Sealant-to-painted metal surface bond strength whilst peeling off:
      3.0 N/cm
      Resistance to low temperatures (-60 °С):
      the sealant doesn’t peel off from the painted metal plate
      Smoke generation coefficient:
      500 m2/kg

Introduction

Result:

  • Our kit helped to reduce the general noise level in the meeting room by 2-2.5 dB and to achieve the average level of 74.4 dB.
  • This noise level fits within the level of 75 dB established in the Federal Standard 20296-81 for the first comfort class of long-range aircrafts.