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NASA Plans Mighty Morphing Plane

'Smart' Materials May Lead to Shape-Shifting Planes

Dec. 18 — Remember the shape-shifting villain from the movie Terminator 2: Judgment Day? While the film itself still lies squarely in the realm of sci-fi, it might surprise you to learn that materials that morph from one shape to another actually exist. At NASA's Langley Research Center in Virginia, scientists are using these so-called smart materials to create revolutionary airplanes that can morph in mid-flight.

Known as the Morphing Project, the research is geared toward creating safer, faster planes that, like birds, intuitively change shape to adjust to flight conditions. According to Anna McGowan, the project's manager, the research into next-generation aircraft materials could lead to planes with self-healing wings that flex and react like living organisms.

Smaller, lighter "smart" aircraft that can morph shape could revolutionize civilian transportation. For example, the supersonic Concorde makes only transatlantic runs, due to the sonic boom created at fast flight speeds. But with morphing technology, all commercial flights would be able to fly at the speed of sound — cutting the trip from California to New York down to about 2 hours.

"Morphing technology will enable greater versatility in the same airplane," McGowan said. "You can fly slowly as well as quickly very safely and very efficiently. In addition, we are going to make airplane wings more flexible to maybe fly more like birds, who actually bend and twist their wings in flight to adapt to different flight conditions."

At high speeds, the wings of a morphing plane would sweep back to reduce drag and lower sonic boom. At low speeds, the wings would sweep forward and thicken, allowing for shorter, smoother landings.

Materials With 'Memory'

At the heart of NASA's Morphing Project are "smart materials" that can change shape and feel and register pressure in response to stimuli like heat or electricity.

"This is technology that most people aren't aware even exists," McGowan said.

Such materials include shape-memory alloys, which can easily be molded to take on a new shape but which, when exposed to enough heat, will snap back into their original shape. These alloys can be trained to "remember" any shape as their original form.

Other materials that will play a big role include piezoelectrics, which contort in response to voltage. Conversely, if you contort a piece of piezoelectric material, it will produce voltage. NASA is developing customized versions of piezoelectric materials that can act as sensors and actuators — materials that can create small motions in machines, such as the moving of wing flaps.

According to Dr. Fu-Kuo Chang, a professor of aeronautics and astronautics at Stanford University and an expert on smart materials, specialized piezoelectric materials could prove useful in suppressing vibrations during a flight, which can cause fractures in the body of an aircraft.

"For instance, if you have a vibration on the wing, what you can do is counterbalance the force by exciting the piezoelectric material," Chang said.

Experimental Fighter Jets

The US military is already experimenting using piezoelectric materials to counteract flutter problems with the tail on the F-16, although that research is still years from implementation.

McGowan says these smart materials would be distributed throughout the wings to act as sensors and actuators.

"That's similar to how the human body operates," she said. "We have muscles and nerves all over our bodies, so we are aware of what's happening to our bodies and we can respond to it in a number of ways."

More exotic materials being studied include self-healing metals, which actually repair themselves after damage such as that caused by a bullet. Using molecular modeling software from San Diego-based Accelrys, NASA is working to unravel the secrets of these materials at the atomic level.

Still Decades Away

However, several obstacles remain before NASA's morphing plane can move from futuristic concept to reality.

"First thing, you have to know how to manufacture the material," Stanford's Chang said. "Second is you have to know how to design the material, that is, how to model the material. Once you have these two combined together, you might be able to make better designs in terms of real applications."

NASA acknowledges it could be 20 years or more before its morphing plane takes to the skies, although Chang believes small, unmanned aircraft featuring some morphing capabilities could be less than a decade away.

The Bush administration has shown faith in the feasibility of the Morphing Project, budgeting $150 million for the research over the next five years.

-- Anonymous, December 18, 2001

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neat!

-- Anonymous, December 19, 2001