May 05 2011
There’s a breed of Asian snake that can glide through the air for long distances, something that the Defense Advanced Research Projects Agency (DARPA) is taking a long, close look at.
The flying snakes are found in southern China, Southeast Asia, and in India and can undulate from side to side, unlike other animals that glide with fixed wings or parts of their body that are wing-like.
Jake Socha, a researcher at Virginia Polytechnic Institute and State University, has used a DARPA grant to study the snakes’ physical dynamics in flight and how such information might be used in a military context.
Socha, a professor of engineering science and mechanics and biologist who studies biomechanics, says the Asian snakes live most of their lives in trees, requiring them to move from tree to tree by gliding or flying between them.
“DARPA wasn’t interested in a direct application per se,” Socha says, “but first to understand the fundamental science and mechanics of how these animals can fly.”
Socha collaborated with Pavlos Vlachos, a fluid dynamics expert.
Before an application can be developed, Socha says researchers have to understand how the snake controls its muscles, the texture of its skin, the shape the snake takes when gliding, and the motion it uses in swimming through the air.
Socha notes the snake has a body like a cylinder, not the sort of body type one would begin with to create a flier.
“Mechanically, it seems so ill-suited for gliding, but the snake is able to flatten out its ribbed body, spreading its ribs and making it change from a roughly circular cross-section to more pancake-like,” Socha says. “Its body doubles in width at its widest point, which gives it favorable aerodynamic characteristics that help the snake to glide.”
In addition, the shape of the snake’s body is symmetrical in cross-section fore and aft, Socha pointed out, so when it undulates in the air, “one side of its body faces the oncoming air, but a half-second later that side is on the back side of the wind.”
Socha says understanding how the snake is able to physically produce the forces that allow it to stay balanced in the air without flipping over is a key to the mechanics of its gliding ability.
So is a gliding robotic snake on the horizon for the military?
“I think we’re fairly far away from a robot that can fly like these snakes,” Socha says. “It’s up to DARPA if they want to continue studying the aerodynamics of the snake’s shape in the air.”
About the author: Alan M. Petrillo is a Tucson, Ariz., freelance writer who works in a wide variety of fields, writing for national and regional magazines and newspapers. He’s also the author of the mystery novel, Full Moon, and several books on historical military small arms.