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How Bug Guts Slow Down Planes and What Engineers are Doing About it

Designing the most fuel-efficient plane means keeping wings free of sticky exploded bugs

(Michael Prince/Corbis)
smithsonian.com

There are plenty of challenges to getting a chunk of metal with humans inside it up into the sky. But some are a little more unexpected than others. For The Washington Post, Rachel Feltman writes:

[W]hen a plane plows through a bug (which usually happens during takeoffs and landings), that bug leaves its guts behind. And over time, those guts accumulate and make the surface of the craft's wings less smooth, which creates drag. More drag means more fuel use and a less efficient plane.

The solution? Specialized coatings that keep the smashed bugs from sticking. One team of engineers at NASA’s Langley Research Center goes by the name the "bug team," according to a news release from the center. Along with engineers from Boeing, they recently tested several different coatings on the wings of Boeing’s ecoDemonstrator 757 aircraft. Most bugs hang out in the first 1,000 feet of airspace, so the tests focus on take-offs and landings.

The researchers looked at the number, size and shape of the bug splats peppering the wings. The coatings that worked resulted in bug guts spread over a smaller area and also had a "lower residue height" — the pulped bugs didn’t coat as thickly.

Apparently, engineers have been looking for a solution to bug guts coating plane wings since the 1960s. The bug team’s previous tests have included shooting fruit flies at wings in wind tunnels. They’ve also investigated the bugs themselves. Nick Lavars reports for Gizmag

Part of finding a solution to the problem was studying bug chemistry and what exactly occurs when an insect comes into contact with something at such high speeds. The team found that as the bug's body bursts, its blood actually goes through chemical changes to make it more adhesive.

"That's basically the survival mechanism for the bug," says Mia Siochi, a senior materials scientist at NASA, in the press statement. 

The team turned to nature to figure out how to make the coating that would repel that stickiness. Once of the most successful coatings was inspired by lotus leaves. "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," Siochi says. "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." 

All this work is part of the effort to make airplanes as fuel-efficient as possible. It’s less expensive to fly and ultimately branded as better for the environment. Plus, Feltman points out it’s conceivable that anti-bug-gut coatings could even have other applications — cleaner car windshields, perhaps?

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