The Jeff Wise Blog

World’s First Ornithopter Just Flew. Or Did It?

Something very cool happened last month. Early in the morning of August 2, a student at the University of Toronto took the control’s of the world’s first successful ornithopter — an aircraft that propels itself by flapping its wings like a bird — and flew for 19 seconds. As a lover of strange aircraft and impossible engineering challenges, I applaud the daring and stick-to-itevness of the University of Toronto team, which spent four years creating an incredibly beautiful machine. Here’s the video:

As is obvious from even a cursory viewing, flapping one’s wings is a very difficult way to generate lift. (That birds are so good at it should only renew our respect for the astonishing engineering feats of natural selection.) So the team deserves heartfelt kudos for managing to keep the craft in the air for even a short span of time. But did they really achieve, as a Canadian newspaper reported, “sustained and continuous flight”?

Well, not really. For one thing, as many have pointed out, the plane did not take off under its own power. The University of Toronto team has countered this criticism by pointing out that it managed to maintain airspeed and altitude, and so was more than just gliding. Even if we allow that point, however, I would point out what is to me an even more important problem: the craft never rose to more than a wingspan above the ground, so was never in a condition that I would consider true flight.

When flying close to the ground, a moving wing experiences an extra boost in lift from a phenomenon called “ground effect.” Essentially, proximity with the surface causes a relative increase in the pressure under the wing, allowing it to fly with less drag. A special class of vehicles has been designed to take advantage of this effect, called “wing-in-ground-effect,” or WIG, craft. The Russians built a famously bizarre-looking example, dubbed the “Caspian Sea Monster,” that was 310 feet long and weighed 550 tons, and flew over 300 mph at just 60 feet above the surface. Today, an Illinois company called Universal Hovercraft is building a commercial WIG called the Hoverwing that sells for $85,000:

To me, the most remarkable thing about WIGs is that because they don’t have enough power to climb out of ground effect, the FAA doesn’t consider them aircraft. The Hoverwing is officially a boat. That means you don’t need a pilot’s license to fly one. You don’t need any kind of license at all. Anyone at all can legally hop in, power up the engine, and take off. I recently visited the Universal Hovercraft factory and went for a test flight, and I can assure you that even though you’re only four feet off the ground, it feels just like you’re flying in a plane.

So, from a technical point of view, the University of Toronto ornithopter may have flapped along through the air, but it wasn’t truly flying. If pointing that out qualifies as buzzkill, I hasten to add that it’s in some pretty good company. Some other famous machines that never got out of ground effect include Howard Hughes’ Spruce Goose and Paul MacCready’s Gossamer Albatross, which flew all the way from England to France under human power alone — but in ground effect.

Oh, and of course, let’s not forget the first Wright Flyer, which during its four flights at Kitty Hawk never flew higher than about 10 feet. Yes, that’s right: the first powered heavier-than-air flying machine never actually achieved true flight.

UPDATE: I have just learned that an alternate acronym for a ground-effect boat is “Wing-in-Surface-Effect,” or WISE. I find this vastly preferable.

Filed under: Aviation

2 Responses

  1. Ground effect is helpful, but from my experience not a critical limitation in most cases. Icarus HPA-1 depended on it, but Gossamer Albatross could fly quite easily (but not safely!) out of (above) ground effect. As with certain sea birds, ground effect can be a range extender but the advantage conferred is subtle rather than dramatic, at least with craft like Gossamer Albatross and Daedalus 88. Plus, choppy sea state can completely negate that advantage when your craft has a 100-foot span and flies very slowly. Many tradeoffs.

    • Jeff Wise says:

      Thanks for your expert testimony! I will certainly defer to your judgment — I don’t think anyone has quite the personal, hands-on experience with ground effect that you do.

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Thinking About Fear & the Brain

If I find myself in a severe crisis, will I be able to keep it together? How can I control anxiety and panic? Is it possible to lead a life less bounded by fear? These are the sorts of questions that I'll be exploring in this blog, an offshoot of my book, Extreme Fear: The Science of Your Mind in Danger, published on December 8, 2009 by Palgrave Macmillan.

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