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 successful flights have been reported.
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Sean Kinkade, 1998

Early history

The idea of constructing wings in order to imitate the flight of birds dates to the ancient Greek legend of Daedalus and Icarus. Roger Bacon, writing in 1260, was among the first to consider a technological means of flight. Around 1490, 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. Gustav 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.

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

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Schmid 1942 Ornithopter
Perhaps because the prevailing culture favors 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. [1]

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.[2]

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 made a jet-assisted takeoff and 14-second flight. According to DeLaurier[3], the jet was necessary for sustained flight, but the flapping wings did most of the work.[4]

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, 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.

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.[5] 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.[6]

Ornithopters as a hobby

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The Dragonfly is a popular 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. Students as well as older 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 radio controlled designs stem from Percival Spencer's engine-powered Seagulls, developed circa 1958, and Sean Kinkade's work in the late 1990s. 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.

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.

Ready-made toy ornithopters are available. These include the Tim Bird (made by G de Ruymbeke, France, since 1969) and the radio-controlled Dragonfly from WowWee.

Aerodynamics

As demonstrated by birds, flapping wings offer potential advantages in maneuverability and energy savings compared with fixed-wing aircraft.

Aerodynamically, ornithopters differ from fixed-wing aircraft in that the driving airfoils have a flapping instead of rotary motion. Typically, the driving airfoils are large, so that the volume of air acted on to produce thrust is maximized. Since the flapping airfoils produce both lift and thrust, drag-inducing structures are minimized. These two advantages potentially allow a high degree of efficiency.

From general aerodynamic considerations, ornithopters appear to make more efficient use of power than rotating propeller or jet aircraft do. The difficulties that have prevented major practical application appear to be the required mechanisms and structures, and the comfort of passengers since the ornithopter body typically oscillates counter to the wing motion.

However, the main issue in constructing large manned ornithopters is the problem of wing loading. For similarly shaped flyers, the weight increases as the cube of linear dimension, while the lift-producing surface area increases only as the square of linear dimension. Thus as the payload portion of the flyer gets larger, the wings must increase in size disproportionately in order to maintain wing loading at levels where lift can overcome the craft's total weight. These much larger wings are then more difficult to flap. In bird species, increase in size results in a trend away from flapping flight and toward gliding flight in a pseudo-fixed wing configuration. The largest flying birds currently known, such as the King Vulture and the Stork, are principally gliders.

Sources: [1]

Trivia

References

1. ^ Bruno Lange, Typenhandbuch der deutschen Luftfahrttechnik, Koblenz, 1986.
2. ^ FAI web site.
3. ^ Dr. James DeLaurier's report on the Flapper's Flight July 8, 2006
4. ^ University of Toronto ornithopter takes off July 31, 2006
5. ^ Winged robot learns to fly New Scientist, August 2002
6. ^ 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.

Further reading

  • 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.
  • Chronister, Nathan. (1999). The Ornithopter Design Manual. Published by The Ornithopter Zone.

External links

See also

Greek}}} 
Writing system: Greek alphabet 
Official status
Official language of:  Greece
 Cyprus
 European Union
recognised as minority language in parts of:
 European Union
 Italy
 Turkey
Regulated by:
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aircraft is a vehicle which is able to fly through the air (or through any other atmosphere). All the human activity which surrounds aircraft is called aviation. (Most rocket vehicles are not aircraft because they are not supported by the surrounding air).
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Aves
Linnaeus, 1758

Orders

About two dozen - see section below

Birds (class Aves) are bipedal, warm-blooded, egg-laying vertebrate animals.
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BAT may refer to:
  • Baby AT, a variant of the AT form factor
  • Bangor Area Transit
  • B.A.T., "Bureau of Astral Troubleshooters", a 1990 computer game
  • Batch file, ".BAT", MS-DOS, OS/2, and Windows shell programs
  • BAT (G.I.

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Insecta
Linnaeus, 1758

Orders
Subclass Apterygota
* Archaeognatha (bristletails)
* Thysanura (silverfish)
Subclass Pterygota
* Infraclass Paleoptera (Probably paraphyletic)

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Flight is the main mode of locomotion used by most of the world's bird species. It assists birds while feeding, breeding and avoiding predators.

Evolution and purpose of bird flight


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Daedalus (Latin, also Hellenized Latin Daedalos, Greek Daidalos (Δαίδαλος) meaning "raper", and Etruscan Taitle) was a most skillful artificer, so skillful that he was said to have invented images.
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Icarus (Greek: Ἴκαρος, Latin: Íkaros, Etruscan: Vicare) is a character in Greek Mythology. Icarus's father, Daedalus attempted to escape his prison at the hands of King Minos.
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Roger Bacon, O.F.M. (c. 1214–1294), also known as Doctor Mirabilis (Latin: "wonderful teacher"), was one of the most famous Franciscan friars of his time. An English philosopher who placed considerable emphasis on empiricism, he was one of the earliest European
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Leonardo da Vinci

Self-portrait in red chalk, circa 1512 to 1515. [a]
Birth name Leonardo di Ser Piero
March 15 1452(1452--)
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Lawrence Hargrave (29 January 1850 – 6 July 1915) was an engineer, explorer, astronomer, inventor and aeronautical pioneer.

Early life

Hargrave was born in Greenwich, England, the second son of John Fletcher Hargrave (later attorney-general of New South Wales) and
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Erich von Holst (November 28, 1908 - May 26, 1962), was a German behavioral physiologist who was a native of Riga, and was related to historian Hermann Eduard von Holst (1841-1904). In the 1950s he founded the Max Planck Institute for Behavioral Physiology at Seewiesen, Bavaria.
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Alexander Martin Lippisch (November 2, 1894 – February 11, 1976) was a German pioneer of aerodynamics. He made important contributions to the understanding of flying wings, delta wings and the ground effect.
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Alexander Martin Lippisch (November 2, 1894 – February 11, 1976) was a German pioneer of aerodynamics. He made important contributions to the understanding of flying wings, delta wings and the ground effect.
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Yves Rousseau (France) is credited with some ultralight aircraft FAI world records and has received international recognition for his 13 years of work on human-powered ornithopter flight; Rousseau attempted his first human-powered flight with flapping wings in 1995.
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The University of Toronto Institute for Aerospace Studies, or UTIAS (pronounced you-TIE-us), was established in 1949. It serves as both a premier research institute, and a graduate school, offering masters and doctorate degrees.

It is officially part of the St.
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James D. DeLaurier is an inventor and professor emeritus of the University of Toronto Institute for Aerospace Studies. His research team designed the first microwave-powered aircraft, designed to be used as a high-altitude communications relay platform.
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Location Downsview, Ontario, Canada
Nearest city Toronto, Ontario
Coordinates
Area 2.4 km²
Established 1998

Governing body Parc Downsview Park Inc.
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Centrocercus

Species

Centrocercus urophasianus, (Bonaparte, 1827)
Centrocercus minimus, (Young et al., 2000)
The Greater Sage-grouse, Centrocercus urophasianus, is the largest grouse in North America .
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Gossamer Albatross was a human-powered aircraft built by American aeronautical engineer Dr. Paul B. MacCready's AeroVironment. On June 12, 1979 it completed a successful crossing of the English Channel to win the second Kremer prize.
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Smithsonian Institution (pronounced [smɪθ.ˈso.ni.ˌən]) is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds
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Pterosauria
Kaup, 1834

Suborders

Pterodactyloidea
Rhamphorhynchoidea *

Pterosaurs (/ˈtɛ.
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Quetzalcoatlus
Lawson, 1975

Species

Q. northropi Lawson, 1975 (type)
Q. sp. vide Kellner & Langston, 1996

Quetzalcoatlus
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Robert C. Michelson is an American engineer and academic. He is widely known for inventing the Entomopter at GTRI and for establishing the International Aerial Robotics Competition.

Biography

He was born in Washington D.C.
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The Reciprocating Chemical Muscle (RCM) is a mechanism that takes advantage of the superior energy density of chemical reactions. It is a regenerative device that converts chemical energy into motion through a direct noncombustive chemical reaction.
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SRI International is one of the world's largest contract research institutes. It was founded as Stanford Research Institute in 1946 by the trustees of Stanford University as a center of innovation to support economic development in the region.
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Peter Nordin

Born July 9 1965 (1965--) (age 42)
Helsingborg, Sweden
Residence Sweden
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Chalmers University of Technology or Chalmers tekniska högskola (CTH), often Chalmers, is a university in Gothenburg, Sweden, that focuses on research and education in technology, natural science and architecture.
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machine learning is concerned with the design and development of algorithms and techniques that allow computers to "learn". At a general level, there are two types of learning: inductive, and deductive.
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In artificial intelligence, an evolutionary algorithm (EA) is a subset of evolutionary computation, a generic population-based metaheuristic optimization algorithm. An EA uses some mechanisms inspired by biological evolution: reproduction, mutation, recombination, natural selection
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