Inspired by nature and by the aviation pioneers of the early 20th century, scientists in the US said Wednesday they had built the world's first jellyfish drone aircraft.
The tiny, ultra-light lab machine, weighing just 2.1 grammes (0.07 ounces), is the first man-made flying object to hover and move with a motion like that of the jellyfish in water, the inventors believe.
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| Leif Ristroph |
"Our interest ended up being a little bit weird—it was the jellyfish."
The jellyfish has long been admired by engineers for a simple yet efficient motion, sculpted by millions of years of evolution, that requires just a simple muscle and no brain power, just a primitive nervous system.
It has a bell-like translucent skirt that first billows out and then closes tightly, squirting water out from the small opening to provide itself with movement.
In this case, the aircraft uses four petal-shaped wings, each eight centimetres (four inches) long, that when folded together form a downward-facing "cone."
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| Stephen Childress |
The result is an "ornithopter," or flying machine that hovers with great stability, without the need for constant, energy-draining correction.
"If it's knocked over, it stabilises by itself," Ristroph said to reporters.
The craft can change direction by making one of the four wings work harder than the others.
Pioneers of flight
The materials to make the machine are all over-the-counter components—light carbon-fibre ribs to hold the motor and provide the frames of the wings, which are covered by transparent Mylar film—bought at ordinary modelling stores.
Ristroph said he and Childress had been intrigued by film footage of aviation pioneers who had tried to mimick insects to build ornithopters, but lacked the knowledge or materials at the time.
More information: Stable hovering of a jellyfish-like flying machine, Journal of the Royal Society Interface, rsif.royalsocietypublishing.org/lookup/doi/10.1098/rsif.2013.0992
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