Aerial jellyfish: Ornithopters: Flying like a bird has long captured the imagination. The latest way to do so is copied from the ocean, not the atmosphere

Aerial jellyfish: Ornithopters: Flying like a bird has long captured the imagination. The latest way to do so is copied from the ocean, not the atmosphere

Mar 8th 2014 | From the print edition

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ENGINEERS often look to the natural world for inspiration—and flight engineers, doubly so. Mankind’s desire to soar like the birds directly inspired the Wright brothers’ solution to the problem of controlling a heavier-than-air flying machine, by suggesting the way to do so was to warp the shape of the craft’s wings. More recently, designers of ornithopters (tiny, robotic flying machines lifted by flapping wings) have looked to insects for inspiration, and built systems of sensory feedback that can keep aloft designs which are essentially unstable.

It would be better, though, if those designs were not unstable in the first place, so that any on-board electronics (all of which contribute to a craft’s weight) could concentrate on the more useful task of piloting the thing to its destination, rather than merely keeping it in the air. And that, by looking at a rather different natural model, is what Leif Ristroph and Stephen Childress of New York University think they have done.

Their ornithopter, described in the Journal of the Royal Society Interface, resembles not an insect, but a jellyfish. As Dr Ristroph and Dr Childress note in their paper, this is not the first time flight engineers have used an aquatic rather than an aerial model, for only waterborne creatures (squid, for example) use jet propulsion. Their device, rather than having a continuous bell as a real jellyfish does, relies on four leaf-shaped wings. But that is mainly to simplify the construction, for it means the wings can be rigid (they are made of Mylar films, stretched on tough carbon-fibre frames).

Each wing is 8cm long. The pointed ends of the leaves meet at the apex of what is basically a cone-shaped device, and the wings are held in place relative to one another by a flexible carbon-fibre ring that connects them. Opposite wings, pulled via carbon-fibre threads by a small electric motor, beat simultaneously and out of phase with the other pair of wings to provide lift.

Crucially, when perturbed from outside, this design does not crash to the floor. It needs no fancy controls to stop it tipping over. At the moment, for simplicity, it is powered through a wire that tethers it down. But it would be easy to fit it with a small battery and let it go.

Dr Ristroph and Dr Childress, then, seem to have solved an important problem in ornithopter design. And in doing so they have also shown that evolution, though clever, is not always as clever as human engineers—for as far as is known nature has neither now, nor at any time in the past, come up with the equivalent of aerial jellyfish.

 

About bambooinnovator
Kee Koon Boon (“KB”) is the co-founder and director of HERO Investment Management which provides specialized fund management and investment advisory services to the ARCHEA Asia HERO Innovators Fund (www.heroinnovator.com), the only Asian SMID-cap tech-focused fund in the industry. KB is an internationally featured investor rooted in the principles of value investing for over a decade as a fund manager and analyst in the Asian capital markets who started his career at a boutique hedge fund in Singapore where he was with the firm since 2002 and was also part of the core investment committee in significantly outperforming the index in the 10-year-plus-old flagship Asian fund. He was also the portfolio manager for Asia-Pacific equities at Korea’s largest mutual fund company. Prior to setting up the H.E.R.O. Innovators Fund, KB was the Chief Investment Officer & CEO of a Singapore Registered Fund Management Company (RFMC) where he is responsible for listed Asian equity investments. KB had taught accounting at the Singapore Management University (SMU) as a faculty member and also pioneered the 15-week course on Accounting Fraud in Asia as an official module at SMU. KB remains grateful and honored to be invited by Singapore’s financial regulator Monetary Authority of Singapore (MAS) to present to their top management team about implementing a world’s first fact-based forward-looking fraud detection framework to bring about benefits for the capital markets in Singapore and for the public and investment community. KB also served the community in sharing his insights in writing articles about value investing and corporate governance in the media that include Business Times, Straits Times, Jakarta Post, Manual of Ideas, Investopedia, TedXWallStreet. He had also presented in top investment, banking and finance conferences in America, Italy, Sydney, Cape Town, HK, China. He has trained CEOs, entrepreneurs, CFOs, management executives in business strategy & business model innovation in Singapore, HK and China.

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