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Carbon fiber and other composite materials have revolutionized the aerospace industry over the last two or three decades. In fact, the most advanced aircraft of our day can be made up of more than 50% composite materials by weight. Lightweight but strong composites are what make it possible to build bigger passenger planes without requiring commensurately larger wings and engines.
Materials like carbon fiber weigh a lot less than steel and aluminum but offer higher strength and rigidity, according to Utah-based Rock West Composites. As such, carbon fiber makes a lot of sense as a material for both fuselage and wings. But carbon fiber is not immune to the icing that commonly occurs in-flight. Engineers have to build deicing systems into aircraft wings to prevent dangerous buildup that could result in a loss of lift.
Current deicing solutions for carbon fiber wings are adequate, but they are not nearly as effective and efficient as engineers would like. So aerospace manufacturers are looking for ways to design better deicing systems. They may have found it in carbon nanotubes.
- Lighter and Better Deicers
Current technology calls for the use of heaters built into carbon fiber wings for deicing. When sensors detect ice on the leading edge of a plane’s wings, extra current is sent to the heaters to melt the ice. It works, but the heaters are heavy, inefficient, and extremely dependent on routine maintenance. Engineers would like to get rid of them completely.
Replacing traditional heaters is the goal of a research project at Queen’s University Belfast. Researchers there found a way to manufacture a continuous film of horizontal carbon nanotubes they described as a CNT (carbon nanotube) web. The web is electrically conducive, so it can be used to generate heat for deicing planes.
Researchers figured out a way to stack multiple layers of carbon nanotube webs, bind them together with a glass fiber resin, and connect them with copper foil to a power supply. They tested their design and were able to reach a high temperature of 95°C (194°F) in a relatively short amount of time. Their lab tests indicated they could deice a plane wing in a mere 15 seconds.
To prove the worthiness of the design, the research team also created a similar heater using carbon fiber reinforced plastics (CRFP). The CRFP heater was still more effective than a traditional heater, but it could not compare with the CNT device. It needed 25 seconds to completely deice the test surface and only reached a high temperature of 39°C (102°F).
- Carbon Fiber and Carbon Nanotubes Together
Researchers at Queen’s University Belfast have found a way to combine carbon fiber and carbon nanotubes to make deicing plane wings faster and easier. Elsewhere, carbon fiber and carbon nanotubes are being combined in other ways. More often than not, engineers are looking to improve the structural integrity and rigidity of carbon fiber by adding carbon nanotubes to the equation.
A carbon nanotube is more or less a microscopically small sheet of bonded carbon molecules rolled into a cylindrical shape to form a tube. The tube design increases strength considerably. It’s a lot like inserting rebar into concrete.
Rebar strengthens concrete by absorbing and distributing energy in a way that prevents cracking and splitting. Carbon nanotubes do the same thing. They can be used with carbon fiber materials or other composites to provide extra rigidity.
In the case of airplane wings, the carbon nanotubes are for deicing purposes rather than increased strength. But who knows? Perhaps engineers will be able to accomplish both with future carbon nanotube designs.
