Ornithopter
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An ornithopter is an aircraft that flies by wing-flapping. Many examples exist in nature such as birds, bats, and insects. Man-made ornithopters are usually on the same scale as these flying creatures, though some overscale, manned ornithopters have also been built.
The first ornithopters capable of flight were constructed in France in the 1870s. They were powered by rubber band or, in one case, by gunpowder charges activating a bourdon tube, which flapped the wings (Gustav Trouvé, 1870).
Practical applications for ornithopters capitalize on their resemblance to bird flight. The Colorado Division of Wildlife has used ornithopters to help save the endangered Gunnison Sage Grouse. Ornithopters resembling birds of prey cause the grouse to remain on the ground so they can be captured for study. Ornithopers can also be used to drive flocks of birds away from airports, where they pose a safety hazard. AeroVironment, Inc., led by Paul B. MacCready (Gossamer Albatross), has developed a remotely piloted ornithopter the size of a large insect for possible spy missions. As demonstrated by birds, flapping wings offer potential advantages in maneuverability and energy savings compared with fixed-wing aircraft.
MacCready also developed, for the Smithsonian Institution, a half-scale replica of the giant pterosaur, Quetzalcoatlus northropi. The model had a wingspan of 5.5 meters (18 feet) and featured a complex, computerized control system, just as the full-size pterosaur relied on its neuromuscular system to make constant adjustments in flight.
Ornithopters are also built and flown by hobbyists. These range from light-weight models powered by rubber band, to larger, radio control ornithopters. Current designs stem from Percival Spencer's engine-powered ornithopters, developed circa 1958, and Sean Kinkade's work in the late 1990s. Electric motors or piston engines provide the power to flap the wings.
A research project by Georgia Tech scientist Robert Michelson is developing a reciprocating chemical muscle for use in micro-scale aircraft with flapping wings. SRI International is developing polymer artificial muscles for use in ornithopters and other applications.
Many attempts at manned ornithopter flight have been made, only a few of which have been successful. Adalbert Schmid developed a motorized, manned ornithopter that made extended flights in 1942 (Weltluftfahrt, March 1950, p. 195). From 1990-1995, Vladimir Toporov and students built a tow-launched ornithopter that reportedly could be made to climb as a result of the pilot's muscular effort. Currently (as of 2004), a team at the University of Toronto's Institute for Aerospace Studies, headed by professor James DeLaurier, is working on an engine-powered, manned ornithopter designed to take off unaided.
In science-fiction
The ornithopter is familiar to readers of Frank Herbert as the primary means of on-planet travel by the inhabitants of the Dune universe. The retro film Sky Captain and the World of Tomorrow features ornithopters in dog fights against fixed-wing aircraft.
External links
- The Ornithopter Zone web site (http://www.ornithopter.org)
- University of Toronto ornithoper project (http://www.ornithopter.net)
- Fly the Ornithopter yourself with the OpenSource flightsimulator FlightGear (http://www.flightgear.org/)da:Ornitopter