'Flying carpet' of conductive plastic takes flight

By Roland Pease BBC News
Two frequencies of cycling show the sheet "rippling" in a display of small propulsive force

A miniature magic carpet made of plastic has taken flight in a laboratory at Princeton University.

The 10cm (4in) sheet of smart transparency is driven by "ripple power"; waves of electrical current driving thin pockets of air from front to rear underneath.

The prototype, described in Applied Physics Letters, moves at speeds of about a centimetre per second.

The researchers stress that the design shows propulsion, but not yet lift.

Improvements to the design could create both aerodynamic lift and raise the propulsion speed to as much as a metre per second.

The device's creator, graduate student Noah Jafferis, was inspired by a mathematical paper he read shortly after starting his PhD studies at Princeton - but putting it into practice was no straightforward task.

"What was difficult was controlling the precise behaviour of the sheet as it deformed at high frequencies," Prof James Sturm, who leads Mr Jafferis' research group, told the BBC.

"Without the ability to predict the exact way it would flex, we couldn't feed in the right electrical currents to get the propulsion to work properly."

What followed was a two year digression attaching sensors to every part of the material so as to fine-tune its performance through a series of complex feedbacks.

But once that was mastered, the waveform of the undulating matched that prescribed by the theory, and the wafting motions gave life to the tiny carpet.

You can listen to Noah Jafferis describe his flying carpet on the BBC World Service programme Science in Action.
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