Bugged, NASA Fights Back with Coatings

FRIDAY, JUNE 5, 2015

SHREVEPORT, LA--Not much bugs NASA scientist Mia Siochi as much as clods of insect guts that pile up on wings and cause aircraft to eat more fuel.

So Siochi, the senior materials scientist at NASA's Langley Research Center in Virginia, and her NASA "bug team" set out to find nonstick coatings that would help prevent insect debris from accumulating on 757s.

The team then tested five of those materials on Boeing's ecoDemonstrator. Preliminary results released Monday (June 1) indicate the team did well.

"One of the five coating/surface combinations showed especially promising results," said Fay Collier, project manager with the group Environmentally Responsible Aviation, which analyzed the study.

"There still is a lot of research to be done, but early data indicated one coating had about a 40 percent reduction in bug counts and residue compared to a control surface mounted next to it."

Running the Tests

Preventing bug buildup on airplanes is an area of research that dates to the 1960s.

Recently, the scientists at Langley tried out more than 200 types of coatings in a wind tunnel and on flights in Virginia before taking the finalists to Louisiana for more testing.

There, the team took the Boeing super jet on several test flights at Shreveport Regional Airport. Bugs fly close to the ground, so the majority of the testing during that two-week period involved how well the coatings worked on takeoffs and landings.

Scientists from NASA, Boeing, the U.S. Department of Transportation, and University of California-Davis chose Shreveport because of its large insect population.

The tests in Shreveport were part of a series of studies looking at how to prevent drag that slows down planes and causes otherwise-efficient aircraft to lose fuel, said Siochi.

'Little Bugs that Trip the Flow'

"Laminar aircraft wings are designed to be aerodynamically efficient," said Siochi. "An aircraft that's designed to have laminar wings flying long distance can save 5 (percent) to 6 percent in fuel usage. Surprisingly, all you need are little bugs that trip the flow, and you lose part of this benefit."

To make their products, NASA scientists had to find out more about a bug's chemical makeup and what causes the splatter to stick. They also turned to Lotus leaves for help.

NASA Langley / David C. Bowman

Bug splatters like this can cause an otherwise-efficient airplane to lose significant fuel. NASA has just finished testing five nonstick coatings it hopes will slough the bug goo and prevent fuel loss on takeoffs and landings.

"When you look at a lotus leaf under the microscope, the reason water doesn't stick to it is because it has these rough features that are pointy," said Siochi.

"When liquid sits on the microscopically rough leaf surface, the surface tension keeps it from spreading out, so it rolls off. We're trying to use that principle in combination with chemistry to prevent bugs from sticking."

Debugging the Future

Once the study is complete, NASA will release its findings to the general public, minus the proprietary technical information maintained by Boeing about its airplane. But that doesn't necessarily mean bug coatings will be making an appearance on commercial airplanes anytime soon.

Not only do the coatings have to stand up to different sizes of bugs and bug splatters, but they also have to be able to last for years while being more cost-effective than the amount of fuel the plane would lose without them.

"So we have to get through that hurdle of practical application of these materials," said Siochi.


Tagged categories: Aviation; Coating chemistry; Coating Materials; Coatings Technology; Energy efficiency; NASA; North America; Research; Specialty Coatings

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