Revolutionary Noise Reduction Approach: Graphene Aerogels

Aerogels aren't gels. They are solids derived from gels. In the manufacturing process, the material is freeze-dried to remove the water content from the base material, leaving behind a skeleton that is close to 99 percent lighter than the original material. Depending on the formulation---aerogels can be formed from a variety of substances---they can be incredibly strong, too.

And the latest aerogel is being specifically targeted toward noise reduction applications. Because it is so good at blocking sounds--the science behind how this works is remarkably complicated but well understood---it is being envisioned as an insulator for turbine engines. Researchers have calculated that the material could take the noise signature of large jets down by the previously mentioned 16 dB, which would not only make the aircraft much quieter for those on the ground below them but also far quieter for the passengers and crewmembers, who much endure the sound of the engines for the entirety of the flight, often for many hours straight. Smaller planes are louder for the occupants than larger jets, for a variety of easily intuited reasons, including the engines' distance from the cabin and designers' freedom to employ larger-scale soundproofing solutions.

Another property of aerogels is tunability. Different soundproofing materials are generally good at certain frequencies and not as effective at others. Aerogels can be manufactured with an application in mind to be effective at chosen frequencies; that is, they can be tuned specifically to the application.

And because they are so remarkably light in weight, they can be used with almost zero weight penalty. One potential application, to provide anti-icing to the wings of planes, would use a super thin blanket of aerogel that was heated to prevent the formation of ice on it. The entire blanket coating a large aircraft's wings would weigh only a few grams. It's a theoretical application that would be difficult or impossible to implement but that shows the promise of the materials.

In terms of soundproofing, however, the researchers suggest there are no major deal-breakers, and the benefits are overwhelmingly positive.

As far as small planes are concerned, could such soundproofing---if it were to be cost-effective---produce similar results? Don't throw away your headsets yet. Small planes don't promise any such easy fixes, as noise is created not just by the loud engines we fly directly behind but also because propellers are very noisy, as is the rushing of air over the plane's surface.

Airport Neighbors Unhappier About Noise Than Ever Despite Far Quieter Planes