All Tech Considered
2:12 pm
Tue August 16, 2011

Air Force Eyes Artificial Birds, Bugs That Can Spy

At the Wright–Patterson Air Force Base in Dayton, Ohio, some Ph.D. candidates are working on micro air vehicles, or tiny flying machines that are remotely piloted.

The micro machines are often "bio-inspired" — study a bird or an insect and then build one.

"If you close your eyes and think of a fat pigeon, that's about the biggest size that we want to use." says Leslie Perkins, who worked with the micro program at the Air Force Research Laboratory. She says the smallest would be about the size of a dragonfly.

These are gentle images of nature, but the micro vehicles would be used by what the research lab calls the "warfighter," to "improve total weapon agility."

Ph.D. candidate Steve Ross is ready to fly his small quad-rotor helicopter, which is about the size of a laptop. It has four motors that work in opposition, so it can rise and dip and bank.

Ross is a lieutenant colonel working on a doctorate at the Air Force Institute of Technology at Wright-Patterson. And he says this project will be his dissertation.

"These little tiny [unmanned aerial vehicles] are great for surveillance, or looking around, or collecting data that way, but they're very short on battery power," he says.

Early Research

Ross is working on a system that would let the micros steal power from utility lines. They'll fly up in a slow approach, and then use a hook to catch on.

"Hang a couple on a power line to recharge batteries, send one of them on site and you just cycle through like you were coming off of a tanker and you can keep one guy on station all the time and have a continuous presence," he says.

On another workbench nearby, a carbon-fiber wing about the size of your thumb is connected to a small motor and poised to flap.

"The Latin term is Manduca sexta, and it's the tobacco hawk," says Maj. Ryan O'Hara. "And it's basically a very common moth than can hover."

O'Hara has been working on his Ph.D. project for two years — the bio-engineering is based on a moth you could find in your garden.

"The individual fibers are about seven microns in diameters," he says. The average size human hair is about 75 microns. "So we take these very, very thin carbon fibers, and we put them in epoxy resin, and we lay them up in different orientations," O'Hara says.

O'Hara flips on the motor and the wing quickly blurs, flapping 30 times per second. Then a strobe light stops the motion, and there's the elegant deflection of the wing, curving as if in flight.

The Air Force says this is early research into the potential of micro aircraft, and it doesn't know how it'll be used.

Fiction writers of course have no hesitation — they could describe an insect buzzing through an open window — an almost silent nighttime attack.

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