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|name = Ornithopter
|name = Ornithopter
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|caption = Sean Kinkade Skybird
|caption = Cybird Radio Controlled Ornithopter
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Revision as of 19:24, 27 June 2010

Ornithopter
File:CybirdP1.gif
Cybird Radio Controlled Ornithopter

An ornithopter (from Greek ornithos "bird" and pteron "wing") is an aircraft that flies by flapping its wings. Designers seek to imitate the flapping-wing flight of birds, bats, and insects. Though machines may differ in form, they are usually built on the same scale as these flying creatures. Manned ornithopters have also been built, and some have been successful.

Early history of the Ornithopter

The idea of constructing wings in order to resemble the flight of birds dates to the ancient Greek legend of Daedalus (Greek demigod engineer) and Icarus (Daedalus's son). One of the first recorded – still dilettante – attempts with gliders were those by the 11th century monk Eilmer of Malmesbury (recorded in the 12th century) and the 9th century poet Abbas Ibn Firnas (recorded in the 17th century); both experiments ended with lasting injuries to their pilots.[1] Roger Bacon, writing in 1260, was among the first to consider a technological means of flight. In 1485 , Leonardo da Vinci began to study the flight of birds. He grasped that humans are too heavy, and not strong enough, to fly using wings simply attached to the arms. Therefore he proposed a device in which the aviator lies down on a plank and works two large, membranous wings using hand levers, foot pedals, and a system of pulleys.

The first ornithopters capable of flight were constructed in France in the 1870s. Gustave Trouvé's 1870 model flew a distance of 70 meters in a demonstration for the French Academy of Sciences. The wings were flapped by gunpowder charges activating a bourdon tube. Jobert in 1871 used a rubber band to power a small model bird. Alphonse Penaud, Hureau de Villeneuve, Victor Tatin, and others soon followed with their own designs.

Around 1890, Lawrence Hargrave built several ornithopters powered by steam or compressed air. He introduced the use of small flapping wings providing the thrust for a larger fixed wing. This eliminated the need for gear reduction, thereby simplifying the construction. To achieve a more birdlike appearance, this approach is not generally favored today.[citation needed]

In the 1930s, Erich von Holst carried the rubber band powered bird model to a high state of development and great realism. Also in the 1930s, Alexander Lippisch and other researchers in Germany harnessed the piston internal combustion engine.

Manned flight

Schmid 1942 Ornithopter
File:UTIAS Ornithopter Flight.jpg
The UTIAS Ornithopter No.1

Perhaps because the prevailing technology is fixed-wing aircraft, people are mainly aware of the failed attempts at flapping-wing flight. This article describes only the more successful attempts. The machines are of two general types: those with engines, and those powered by the muscles of the pilot.

In 1929, a man-powered ornithopter designed by Alexander Lippisch flew a distance of 250 to 300 meters after tow launch. The flight duration was necessarily short due to the limitations of human muscle power. Since a tow launch was used, some have questioned whether the aircraft was capable of sustained flight, however brief. Lippisch asserted that the aircraft was actually flying, not making an extended glide. Later tow-launched flights include Bedford Maule (1942), Emil Hartmann (1959), and Vladimir Toporov (1993). All faced similar limitations due to the reliance on human muscle power.

In 1942, Adalbert Schmid flew a motorized, manned ornithopter at Munich-Laim. It was driven by small flapping wings mounted at the sides of the fuselage, behind a larger fixed wing. Fitted with a 3 hp Sachs motorcycle engine, it made flights up to 15 minutes in duration. Schmid later constructed a 10 hp ornithopter based on the Grunau-Baby IIa sailplane, which was flown in 1947. The second aircraft had flapping outer wing panels.[2]

In 2005, Yves Rousseau was given the Paul Tissandier Diploma, awarded by the FAI for contributions to the field of aviation. Rousseau attempted his first human-muscle-powered flight with flapping wings in 1995. On 20 April 2006, at his 212th attempt, he succeeded in flying a distance of 64 metres, observed by officials of the Aero Club de France. Unfortunately, on his 213th flight attempt, a gust of wind led to a wing breaking up, causing the pilot to be gravely injured and rendered paraplegic.[3]

A team at the University of Toronto Institute for Aerospace Studies, headed by Professor James DeLaurier, worked for several years on an engine-powered, piloted ornithopter. In July 2006, at the Bombardier Airfield at Downsview Park in Toronto, Professor DeLaurier's machine, the UTIAS Ornithopter No.1 made a jet-assisted takeoff and 14-second flight. According to DeLaurier,[4] the jet was necessary for sustained flight, but the flapping wings did most of the work.[5]

Recent developments

Practical applications capitalize on the resemblance to birds or insects. The Colorado Division of Wildlife has used these machines to help save the endangered Gunnison Sage Grouse. An artificial hawk under the control of an operator causes the grouse to remain on the ground so they can be captured for study.

Because ornithopters resemble birds or insects, they could be used for military applications, such as spying without alerting the enemies that they are under surveillance. 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.

MacCready also developed in the mid-1980s, for the Smithsonian Institution, a half-scale radio controlled replica of the giant pterosaur, Quetzalcoatlus northropi. It was built to star in the IMAX movie On the Wing. The model had a wingspan of 5.5 meters (18 feet) and featured a complex, computerized autopilot control system, just as the full-size pterosaur relied on its neuromuscular system to make constant adjustments in flight.

Researchers hope to eliminate the motors and gears of current designs by more closely imitating animal flight muscles. Georgia Tech scientist Robert C. Michelson is developing a Reciprocating Chemical Muscle for use in micro-scale flapping-wing aircraft. Michelson uses the term "entomopter" for this type of ornithopter. SRI International is developing polymer artificial muscles which may also be used for flapping-wing flight.

In 2002, Krister Wolff and Peter Nordin of Chalmers University of Technology in Sweden, built a flapping wing robot that learned flight techniques.[6] The balsa wood design was driven by machine learning software technology known as a steady state linear evolutionary algorithm. Inspired by natural evolution, the software “evolves” in response to feedback on how well it performs a given task. Although confined to a laboratory apparatus, their ornithopter evolved behavior for maximum sustained lift force and horizontal movement.[7]

Since 2002, Prof. Theo Van Holten has been working on an ornithopter which is constructed like a helicopter. The device is called the ornicopter [8] and was made by constructing the main rotor so that it would have no reaction torque at all.

In 2008, Schiphol Airport started using a real looking mechanical hawk designed by falconer Robert Musters. The radio controlled robot bird is used to scare away birds that could damage the engines of airplanes.[9][10]

Ornithopters as a hobby

File:FlyTech Dragonfly 1.jpg
The Dragonfly is a toy made by Wow-Wee.

Hobbyists can build and fly their own ornithopters. These range from light-weight models powered by rubber band, to larger models with radio control.

The rubber-band-powered model can be fairly simple in design and construction. Hobbyists compete for the longest flight times with these models. An introductory model can be fairly simple in design and construction, but the advanced competition designs are extremely delicate and challenging to build. Roy White holds the US national record for indoor rubber-powered, with his flight time of 21 minutes, 44 seconds.

Commercial free-flight rubber-band powered toy ornithopters have long been available. The first of these was sold under the name Tim Bird in Paris in 1879.[11] Later models were also sold as Tim Bird (made by G de Ruymbeke, France, since 1969).

Commercial radio controlled designs stem from Percival Spencer's engine-powered Seagulls, developed circa 1958, and Sean Kinkade's work in the late 1990s to present day. The wings are usually driven by an electric motor. Many hobbyists enjoy experimenting with their own new wing designs and mechanisms. The opportunity to interact with real birds in their own domain also adds great enjoyment to this hobby. Birds are often curious and will follow or investigate the model while it is flying. In a few cases, RC birds have been attacked by birds of prey, crows, and even cats. More recent cheaper models such as the Dragonfly from WowWee have extended the market from dedicated hobbyists to the general toy market,

Some helpful resources for hobbyists include The Ornithopter Design Manual, book written by Nathan Chronister, and The Ornithopter Zone web site, which includes a large amount of information about building and flying these models.

Aerodynamics

Main article: Aerodynamics

As demonstrated by birds, flapping wings offer potential advantages in maneuverability and energy savings compared with fixed-wing aircraft, as well as potentially vertical take-off and landing. It has been suggested that these advantages are greatest at small sizes and low flying speeds.[12]

Unlike airplanes and helicopters, the driving airfoils of the ornithopter have a flapping or oscillating motion, instead of rotary. As with helicopters, the wings usually have a combined function of providing both lift and thrust. Theoretically, the flapping wing can be set to zero angle of attack on the upstroke, so it passes easily through the air. Since typically the flapping airfoils produce both lift and thrust, drag-inducing structures are minimized. These two advantages potentially allow a high degree of efficiency.

  • Robert Altman's 1970 movie, Brewster McCloud, centers around a young man and his project to build a manned ornithopter.
  • Frank Herbert's Dune universe features ornithopters (colloquially called 'thopters) as one of the primary modes of transportation on the desert planet Arrakis.
  • In the Bioware game Jade Empire, ornithopters are used by the characters to travel over long distances and are pivotal to many of the games sidequests.
  • In Michael Moorcock's Hawkmoon series the evil empire of Granbretan uses ornithopters.
  • Many of the movies made by Hayao Miyazaki feature ornithopters, many featuring wings like insects.
  • The Star Wars film Revenge of the Sith depicts a dragonfly-like vehicle being operated by the Wookiees during battle on their home planet of Kashyyyk.[13]
  • In the movie Chicken Run, the "crate" that the chickens build to escape from Mrs. Tweedy's Farm closely resembles the design of an ornithopter. However, it also utilizes a propeller and a tail fin like that of an airplane.
  • In the Airborn trilogy written by Kenneth Oppel, ornithopters are a major form of transportation.
  • The Novel Soft Target: The Air (2007) by Joel Narlock has as a central feature the use of the Entomopter in a spy plot.[14]
  • In the collectible card game Magic: The Gathering there is a card named Ornithopter. The artwork on various versions of the card depict different forms of flying machines. There is also a larger group of Ornithopter like machines, called Thopters. Ornithopters play a large role in the game's plot as well.[15]
  • In Madagascar 2, the penguins build an ornithopter-like airplane powered by chimps.
  • In the book Freak the Mighty, Freak owns a ornithopter.
  • In the Ubisoft game Assassin's Creed II, Leonardo Da Vinci builds a proto-type Ornithopter for the game's main character for use in two missions. However, in use the machine seems to owe more to the hang glider and is dependent on thermal updraughts to keep it airborne.
  • In Chip n' Dale's Rescue Rangers an ornithopter and half blimp is used as the Ranger plane.
  • In the PC game of Obsidian, the player gets to operate a moth-like ornithopter which, in a dreamy rendering, is powered via a zoetrope driven by robotic pillbugs.
  • In the book Peter and the Sword of Mercy, Wendy Darling travels to Mollusk Island on a wooden ornithopter invented by her uncle Neville.

See also

References

  1. ^ White, Lynn. "Eilmer of Malmesbury, an Eleventh Century Aviator: A Case Study of Technological Innovation, Its Context and Tradition." Technology and Culture, Volume 2, Issue 2, 1961, pp. 97–111 (97–99 resp. 100–101).
  2. ^ Bruno Lange, Typenhandbuch der deutschen Luftfahrttechnik, Koblenz, 1986.
  3. ^ FAI web site.
  4. ^ Dr. James DeLaurier's report on the Flapper's Flight July 8, 2006
  5. ^ University of Toronto ornithopter takes off July 31, 2006
  6. ^ Winged robot learns to fly New Scientist, August 2002
  7. ^ Creation of a learning, flying robot by means of Evolution In Proceedings of the Genetic and Evolutionary Computation Conference, GECCO 2002 (pp. 1279-1285). New York, 9-13 July 2002. Morgan Kaufmann. Awarded "Best Paper in Evolutionary Robotics" at GECCO 2002.
  8. ^ Ornicopter project
  9. ^ Article in Dutch newspaper Trouw, partial translation:..."The so-called 'Horck', an electrical controllable bird is the newest means to scare birds. Because they can cause much damage to airplanes. (...) ...it is a design by Robert Musters, a falconer from Enschede"
  10. ^ A picture of the bird with English description
  11. ^ "FLYING HIGH: Bird Man". Scientific American Frontiers Archive. Retrieved 2007-10-26.
  12. ^ T.J. Mueller and J.D. DeLaurier, "An Overview of Micro Air Vehicle Aerodynamics", Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications, Paul Zarchan, Editor-in-Chief, Volume 195, AIAA, 2001
  13. ^ StarWars.com | Wookiee ornithopter
  14. ^ Narlock, Joel (2007-07-20). "Soft Target: The Air". Dan River Press/Conservatory of American Letters, ISBN 0-89754-227-4, ISBN 978-0-89754-227-2, 304 pages. Retrieved 2007-08-28.
  15. ^ Magic: The Gathering Card database | Ornithopter card

Further reading

  • Chronister, Nathan. (1999). The Ornithopter Design Manual. Published by The Ornithopter Zone.
  • Mueller, Thomas J. (2001). "Fixed and flapping wing aerodynamics for micro air vehicle applications". Virginia: American Institute of Aeronautics and Astronautics. ISBN 1-56347-517-0
  • Hallion, Richard P. (2003). Taking Flight: Inventing the Aerial Age from Antiquity through the First World War. New York: Oxford University Press. ISBN 0-19-516035-5.
  • Azuma, Akira (2006). "The Biokinetics of Flying and Swimming". Virginia: American Institute of Aeronautics and Astronautics 2nd Edition. ISBN 1-56347-781-5.
  • David E. Alexander (2009) Why Don't Jumbo Jets Flap Their Wings?, Rutgers University Press. ISBN 978-0-8135-4479-3
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