Shakespeare wrote it in his play "The Winter's Tale": "Everything freezes." At Battelle, an ingenious innovation using carbon nanotubes may prove the Bard of Avon wrong.
Scientists at Battelle have worked for nearly a decade to overcome ice buildup on aircraft. Recently, they developed an environmentally friendly deicing fluid that can be sprayed on planes prior to flight. Now those same scientists have created a technology that will work to prevent ice from forming during in-flight applications that could change the way this problem is solved in the future.
When a plane is in the air, icing can occur if conditions and elevations are right -- even when it's not winter or in areas people think of as a desert, such as Iraq or Afghanistan. When icing occurs, the plane's performance suffers and disasters can occur. Battelle's clever answer for the problem is to apply a carbon nanotube coating to important flight surfaces then energize that coating using the plane's on-board electrical system. This causes the nanotubes to heat up, thus preventing ice from forming.
"At Battelle, we have made significant advancements in nanotechnology during the past eight years," said Amy Heintz, research scientist for Battelle. "With our advanced understanding of the dispersion and functionality of carbon nanomaterials, this technology is one of the more exciting emerging commercial applications of our work."
One immediate use for Battelle's innovative technology is coating unmanned aerial vehicles (UAVs). In the past five years, America's military community has rapidly increased its use of these airplanes in theaters of battle around the world, having performed nearly 500,000 flight hours in combat, greatly multiplying America's military manpower. Typically, UAVs don't have much extra capacity for non-mission critical systems. The vast majority don't have anti-icing systems, which leads to cancelled missions -- studies show about 12 percent -- or sometimes even a crash after the wings become icy.
"As we were developing this nanotechnology, we saw immediately its huge potential for UAVs," said Heintz. "With this technology, we believe the opportunity exists to greatly increase the total operating flight hours of UAVs. That means more planes in the air for a longer time, which helps support our nation's mission."
Battelle's product is radically different from other ice prevention systems such as bleed air (heating the surface with engine bleed air), mechanical boot (breaking the bond between surface and ice) or weeping wing (releasing toxic antifreeze fluid from the wing). Why? Because they can be too complex, too heavy or draw too much power to be effective on a UAV. Battelle's nanotube technology answer -- which weighs 1/100th of current ice protection systems -- is applied using simple painting methods and can be applied to a variety of curved surfaces without needing a custom heater pad design.
Battelle scientists believe that this may be a potential game changing technology that could provide an affordable, durable, lightweight solution. As the development of this technology continues, Battelle anticipates looking at potential opportunities in other fields that would benefit from this technology such as anti-icing for wind turbines. The technology has the potential for a wide range of applications outside the aviation field as well.
Testing in January at a closed-loop ice tunnel showed that the Battelle anti-icing coating successfully prevented ice buildup under a number of simulated icing conditions.
"The icing tunnel tests validated the performance abilities of this system within the power constraints and flight conditions UAVs are typically subjected to," said Brett Burton, a Battelle research scientist. "Now that we have reached this successful stage, we can move to larger demonstrations of the system's capabilities."