The state of the art in thermo-acoustic insulation requires the installation of insulating panels on the metal fuselage from inside the aircraft. This leads to longer times and costs for the maintenance operations of electrical systems and the heating system due to the limited accessibility to such systems. The basic idea isn’t to install the insulation on the metal structure, but on the aircraft’s inside panels on the outside (outboard). In this way, maintenance times and costs are reduced. By removing the internal panels, the thermo-acoustic insulation is also removed with them, thus meeting a maintenance requirement.
Raising the bar for small aircraft thermal insulation and acoustics
The EU-funded SPAIN project set out to design, develop, test and deliver a demonstrator for an integrated thermo-acoustic insulation system. “We want to achieve effective thermal and acoustic insulation for general aviation aircraft that also incorporates the concept of an installation on the side of the interior panels,” says project coordinator Giuliano Di Paola. “This will reduce the costs and time required for electrical and heating system maintenance.” The SPAIN team identified higher-performance insulation panels with low weight in each of the aircraft’s areas. This was done to bring the thermal-acoustic insulation of general aviation aircraft towards higher quality standards than existing ones, maintain a low overall weight, and reduce costs and time for electrical and heating system maintenance. “The results obtained are promising, but a further phase is needed that, taking up the concepts developed in the project, is aimed at industrialisation,” explains Di Paola. “For example, improving the method and materials used to install the insulation on the interior panels.” The team carried out this installation with an adhesive and Velcro strips to avoid holes on the interior panels.
Keeping passenger comfort experience at high levels
To improve sound insulation, project partners also investigated a solution that involves the use of Helmholtz resonators in order to reduce the noise at frequencies associated with the propeller blades. The solution yielded satisfactory results, even if limited to some frequency ranges due to the fact that the resonator samples made consisted of two parts (a body and cap) with reduced air tightness. “We laid the groundwork for resuming and developing this concept in order to achieve even higher levels of sound insulation,” notes Di Paola. In addition, they analysed most thermo-acoustic insulation materials currently available on the market. SPAIN is currently in its final phase. With insulating panels now made, the final demonstrator is being installed. “The cabin insulation system will obtain better thermal and acoustic insulation performance than the existing standard of general aviation aircraft,” concludes Di Paola. “It will improve the thermo-acoustic comfort of small aircraft, and also save costs and time in the maintenance of electrical, heating and air conditioning systems.”
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