Scientists look to nature's template for flying machines

Hovering dragonflies and marathoner locusts are being studied to develop micro-aircraft technology that would be used in rescue efforts.

SYDNEY // Australian scientists are a step closer to creating a radical micro-aircraft after decoding the aerodynamic secrets of locusts, some of nature's most adept flyers. The goal is to build miniature robots the size of a coin that could search for earthquake victims trapped deep in rubble or help the military chart the movements of insurgents in hostile terrain.

Teams from the University of New South Wales and collaborators at Oxford University in Britain exposed the locusts to wind-tunnel experiments and used high-speed digital video cameras to record how the shape of a locust's fast-moving wings changes in flight and to unlock the keys to the insect's manoeuvrability. Researchers have, for the first time, been able to solve some of the mysteries that make the desert locust such a streamlined flyer. They constructed a three-dimensional map that demonstrates a complex flapping movement that allows the locust to travel vast distances on limited reserves of energy.

Only now are scientists starting to fully appreciate the extraordinary abilities of insects. "For example, a dragonfly can pull 12 Gs; it can fly forwards, backwards, up, down and it can hover. It can do all sorts of amazing things. Locusts are extremely efficient. They can fly very, very long distances on essentially very little fuel. So, learning some of these techniques gives us an insight into aerodynamics that we didn't understand before, but also how we actually can use some of those techniques to build a better robotic flying vehicle," said John Young, from the University of New South Wales.

Mr Young explained that an insect's wing has subtle curves and twists with delicate ridges and wrinkles - the antithesis of an aircraft wing - that allow it to travel quickly, traverse long distances and fly backwards in some instances, among other things. Once the computer model of a locust in flight was perfected, the university teams undertook further tests to establish why the structure of the wing was so intricate.

The results have shown that replicating the lift of one of the planet's most gifted aviators would be easy to achieve, but imitating the locust's extraordinary endurance promises to be far more challenging. Still, Joseph Lai, one of the analysts at the University of New South Wales, said he believes the natural world can provide vital clues that will make micro-aircraft a reality. Regardless of their specific area of research, he said, most scientists are looking towards nature to see why it is so efficient. "We can learn from that. The key to me is it is pretty difficult to copy exactly what nature does and so it is important to actually learn from it and come up with our own way of exploiting some of the key features that we discover in these types of studies," Mr Lai said.

Other groups around the world are developing tiny robotic vehicles, including engineers in the United States who are working on a prototype so small it would fit onto the end of a finger. "If you could build a vehicle that would be able to navigate a complex three-dimensional environment like a collapsed building, a flooded area or maybe even something that was on fire, anywhere where you couldn't send people, anywhere where perhaps a ground robot wouldn't be able to make it through because there is a lot of rubble or you need to be able to traverse stairwells or lift shafts, this sort of thing would be extremely useful to find people trapped," he said.

"Of course, anything that would work in that sort of environment would also be very, very useful for the military, for counterterrorism work as well. So, the military are also showing great interest in this," Mr Young added. Disaster officials are likewise monitoring the technology's progress. David Templeman, a former director general of Emergency Management Australia, a federal agency that co-ordinates the government's responses to earthquakes and tsunamis, is convinced it would save lives.

"If we're talking about collapsed structures and trapped people, we have only got a window of 36 hours and that is the timeline normally when we start to seriously lose people through dehydration. The opportunity to deploy a machine the size of a fingernail to get a real fix on where these people are and the environment they are entrapped in would be fantastic," Dr Templeman said. "These things would make all the difference."