WASHINGTON – Since the Wright brothers took to the skies a century ago, aerospace engineers have studied bird flight as the baseline for designing aircraft.
But a special Pentagon research project under way could change that.
A team of engineers and biologists at Brown University has discovered that bats, the mysterious nocturnal mammals that are guided by sound and helped inspire Dracula and Batman, may hold the secret to more efficient flying machines.
The Air Force has taken notice of the research. It will invest $6 million in the project over the next five years, in the hope of using the research to design future military aircraft.
Research so far has found that bats can carry up to 50 percent of their weight and execute airborne maneuvers that would make a bird or plane fall out of the sky. Moreover, scientists believe the hundreds of tiny sensors covering bat wings could be the key to their most impressive airborne maneuvers, a discovery that engineers could replicate with networks of sensors and computers on military aircraft.
If researchers can unlock the secrets of bat flight, it could have wide-reaching implications, according to Air Force and Brown officials. They say the project has the potential to revolutionize aircraft design and could lead to the creation of smaller, more efficient military air vehicles that can maneuver in tight spaces as well as gather intelligence and airlift supplies through forbidding terrain.
“The Air Force envisions a future in which they have lots of autonomous air vehicles that can take on different kinds of missions and that don't have pilots,” said Sharon Swartz, an evolutionary biologist at Brown who is helping run the project. “We know a lot about the aerodynamics of large things moving very fast. There is almost nothing known yet about the basic physics of bat flight.”
Unlike birds or insects, whose wings are comparatively rigid, bats have wings with more than two dozen independent joints, much like a human hand. That allows them to manipulate the thin, flexible membrane that covers the wings in ways that can generate more lift or greatly reduce drag.
Surfaces of bat wings also curve more than a bird's – providing greater lift for less energy – while their extraordinary flexibility allows them to make a 180-degree turn in less than half their wingspan, a radius impossible for any bird or existing plane, according to the initial findings.
The Air Force is particularly interested in how pregnant female bats can fly throughout the gestation period, even though the feat can amount to hauling the addition of half their body weight. Understanding the physics of supporting so much weight in flight could help aircraft designers dramatically increase the payloads of current aircraft models, project officials believe.
Bats, researchers have found, can fly with badly damaged wings and show no discernible changes in flight control – an intriguing discovery that could have dramatic implications for aircraft flight safety.