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An ornithopter (from Greek ornithos "bird" and pteron "wing") is an aircraft that flies by flapping of the wings. Since many examples of flapping-wing flight exist in nature, such as birds, bats, and insects, designers of ornithopters seek to imitate this mode of flight. Ornithopters are usually built on the same scale as these flying creatures, though some scaled-up, person-carrying ornithopters have also been built.

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. He only ever made a small scale model of an ornithopter.

The first ornithopters capable of flight were constructed in France in the 1870s. Gustav Trouvé's 1970 model flew a distance of 70 meters in a demonstration for the French Academy of Sciences. The wings flapped by gunpowder charges activating a bourdon tube. Jobert in 1971 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 engine for the first time.

Flight with Person Onboard

Perhaps because the prevailing culture favors fixed wing aircraft, people are mainly aware of the failed attempts at flapping-wing flight. There have been a few successes as well.

In 1929, the human-muscle-powered ornithopter designed by Alexander Lippisch flew a distance of 250 to 300 meters after tow launch. The flight was extended by the pilot's effort, but it is not clear whether the ornithopter and pilot performed well enough to remain briefly at equilibrium after the tow launch. Later tow-launched flights include Bedford Maule (1942), Emil Hartmann (1959), and Vladimir Toporov (1993).

In 1942, Adalbert Schmid flew a motorized, person-carrying 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]

A team at the University of Toronto Institute for Aerospace Studies, headed by professor James DeLaurier, worked for many years on an engine-powered, piloted ornithopter. In July 2006, DeLaurier's machine made a jet-assisted takeoff and 14-second flight.^[2]

Practical applications

Practical applications for ornithopters capitalize on their resemblance to birds. The Colorado Division of Wildlife has used them 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 they resemble birds, they could theoretically be used for military applications, such as spying without alerting the enemy 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. 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.

A research project by Georgia Tech scientist Robert C. Michelson is developing a Reciprocating Chemical Muscle for use in micro-scale aircraft with flapping wings. Michelson uses the term "entomopter" for this type of ornithopter. SRI International is developing polymer artificial muscles.

Flown by Hobbyists

Ornithopters are also built and flown by hobbyists. These range from light-weight models powered by rubber band, to larger, radio control ornithopters. 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.

Radio controlled designs stem from Percival Spencer's engine-powered ornithopters, developed circa 1958, and Sean Kinkade's work in the late 1990s. The wings are usually driven by an electric motor. Some hobbyists enjoy experimenting with new wing designs and mechanisms, but the RC birds are also available in ready-made form.

Aerodynamics

Aerodynamically, ornithopters differ from fixed wing aircraft in that the driving airfoils have a reciprocating, rather than 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 may produce both lift and thrust, drag-inducing structures are minimized. These two advantages may allow ornithopters to achieve a high degree of efficiency in flight.

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.

References

^ [Bruno Lange, Typenhandbuch der deutschen Luftfahrttechnik, Koblenz, 1986.]
^ Dr. James DeLaurier's report on the Flapper's July 8, 2006 Flight

External links

[1] [Bruno Lange, Typenhandbuch der deutschen Luftfahrttechnik, Koblenz, 1986.]

[2] Dr. James DeLaurier's report on the Flapper's July 8, 2006 Flight

[1]

[2]

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+An '''ornithopter''' (from [[Greek language|Greek]] ''ornithos'' "bird" and ''pteron'' "wing")<!--coinage and first attestation of the term?--> is an aircraft that flies by flapping of the wings.  Since many examples of flapping-wing flight exist in nature, such as [[birds]], [[bats]], and [[insects]], designers of ornithopters seek to imitate this mode of flight.  Ornithopters are usually built on the same scale as these flying creatures, though some scaled-up, person-carrying ornithopters have also been built.
-[[Image:Edward Frost ornithopter.JPG|thumb|200px|Edward Frost of Cambridgeshire, England, constructed an ornithopter of willow, silk, and feathers in 1902]]
-An '''ornithopter''' (from [[Greek language|Greek]] ''ornithos'' "bird" and ''pteron'' "wing")<!--coinage and first attestation of the term?--> is an [[aircraft]] that flies by wing-flapping.  Since many examples of wing-flapping flight exist in nature such as [[birds]], [[bats]], and [[insects]], designers of ornithopters seek to imitate this mode of flight.  Ornithopters are usually built on the same scale as these flying creatures, though some overscale, manned ornithopters have also been built.
 == 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. He only ever made a small scale model of an ornithopter.
-Although there are earlier fanciful accounts of humans flying with artificial wings (such as the ancient Greek tale of [[Icarus (mythology)|Icarus]]), the first person in the Western tradition to propose a mechanical ornithopter seems to have been [[Roger Bacon]]. <ref>[http://www.aeragon.com/air/pio/index.html Aeragon article on Roger Bacon]</ref>
+The first ornithopters capable of flight were constructed in France in the 1870s. Gustav Trouvé's 1970 model flew a distance of 70 meters in a demonstration for the French Academy of Sciences. The wings flapped by gunpowder charges activating a [[Pressure measurement#Bourdon|bourdon tube]]. Jobert in 1971 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.
-A more serious attempt was made c.[[1490]], when [[Leonardo da Vinci]] began to study the flight of birds. He grasped that [[human being]]s are too heavy, and not strong enough, to fly using unaided arms and legs alone.  He proposed an ornithopter having two rocking beams with large flaps driven by the arms and legs working in unison. He also drew a sketch of a more advanced 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. He only ever made a small scale model of an ornithopter.
+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 [[1781]] [[Karl Friederich Meerwein]] is supposed to have succeeded in flying in an ornithopter at [[Gießen]] in [[Germany]], demonstrating that, by applying a large amount of power to a machine of lightweight construction, it should be possible to fly in a heavier-than-air craft.  It is believed today that Meerwein's ornithopter most likely glided after launching from a higher place. <ref>[http://www.wisegeek.com/what-is-an-ornithopter.htm wiseGEEK article on Ornithopter]</ref>
+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 engine for the first time.
-In [[1799]] the English physicist [[George Cayley]] formulated most of the aerodynamic theory of flight, after which ornithopters were mostly abandoned in favour of [[glider]]s.
+== Flight with Person Onboard ==
-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 [[Pressure measurement#Bourdon|bourdon tube]], which flapped the wings (Gustav Trouvé, 1870).
+[[Image:Schmid.jpeg|frame|Schmid 1942 Ornithopter.]]
+Perhaps because the prevailing culture favors fixed wing aircraft, people are mainly aware of the failed attempts at flapping-wing flight. There have been a few successes as well.
-== Piloted flight ==
-[[Image:Flapper Testing Medium.jpg|thumb|De Laurier's ''Flapper'' undergoes testing at Downsview Park in 2005]]
-Many attempts at piloted ornithopter flight have been made, only a few of which have been successful.  In [[1929]] [[Alexander Lippisch]], in [[Germany]], glided in a human-powered ornithopter, but it had to be towed into the air, and did not achieve true flight. In [[1959]] [[Emil Hartman]], in [[England]], also managed the same feat after being towed into the air.
+In 1929, the human-muscle-powered ornithopter designed by [[Alexander Lippisch]] flew a distance of 250 to 300 meters after tow launch. The flight was extended by the pilot's effort, but it is not clear whether the ornithopter and pilot performed well enough to remain briefly at equilibrium after the tow launch. Later tow-launched flights include Bedford Maule (1942), Emil Hartmann (1959), and Vladimir Toporov (1993).
-[[Adalbert Schmid]] developed a motorized, human-carrying aircraft propelled by a set of small flapping wings and sustained with a large fixed wing, which reportedly made extended flights in 1942 [http://www.ornithopter.org/a.schmid.shtml (''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.
+In 1942, [http://www.ornithopter.org/a.schmid.shtml Adalbert Schmid] flew a motorized, person-carrying 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. <ref>[Bruno Lange, Typenhandbuch der deutschen Luftfahrttechnik, Koblenz, 1986.]</ref>
-A team at the [[University of Toronto Institute for Aerospace Studies]], headed by professor [[James DeLaurier]], worked for many years on an engine-powered, piloted ornithopter.  On [[July 8]] [[2006]] at [[Downsview Park]] in [[Toronto]] Professor DeLaurier's ornithopter sustained flight for about a third of a kilometre for 14 seconds <ref>[http://www.thestar.com/NASApp/cs/ContentServer?pagename=thestar/Layout/Article_Type1&call_pageid=971358637177&c=Article&cid=1152395411588 Toronto Star article on The Flapper's 2006 flight]</ref>, having made a jet-assisted takeoff. The brief sustained flight concluded with a damaging landing due to localized buckling along the left wing.<ref>[http://www.ornithopter.ca/Publications/OrnithopterReportfor8July2006.pdf Dr. James DeLaurier's report on the Flapper's July 8, 2006 Flight]</ref>
+A team at the [[University of Toronto Institute for Aerospace Studies]], headed by professor [[James DeLaurier]], worked for many years on an engine-powered, piloted ornithopter.  In July 2006, DeLaurier's machine made a jet-assisted takeoff and 14-second flight.<ref>[http://www.ornithopter.ca/Publications/OrnithopterReportfor8July2006.pdf Dr. James DeLaurier's report on the Flapper's July 8, 2006 Flight]</ref>
-== Modern practical applications ==
-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. Ornithopters 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.
+== Practical applications ==
+Practical applications for ornithopters capitalize on their resemblance to birds. The Colorado Division of Wildlife has used them 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 they resemble birds, they could theoretically be used for military applications, such as spying without alerting the enemy 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. 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.
+A research project by [[Georgia Tech]] scientist [[Robert C. Michelson]] is developing a [[Reciprocating Chemical Muscle]] for use in micro-scale aircraft with flapping wings. Michelson uses the term "entomopter" for this type of ornithopter. [[SRI International]] is developing polymer artificial muscles.
-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.
+== Flown by Hobbyists ==
+Ornithopters are also built and flown by hobbyists. These range from light-weight models powered by rubber band, to larger, [[radio control]] ornithopters.
+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.
+Radio controlled designs stem from Percival Spencer's engine-powered ornithopters, developed circa 1958, and Sean Kinkade's work in the late 1990s. The wings are usually driven by an electric motor. Some hobbyists enjoy experimenting with new wing designs and mechanisms, but the RC birds are also available in ready-made form.
-A research project by [[Georgia Tech]] scientist [[Robert C. Michelson]] is developing a [[Reciprocating Chemical Muscle]] for use in micro-scale aircraft with flapping wings called the [[Entomopter]]. [[SRI International]] is developing polymer artificial muscles for use in ornithopters and other applications.
-Because ornithopters resemble birds, they could theoretically be used for military applications, such as spying without alerting the enemy that they are under surveillance.
 == Aerodynamics ==
-[[Aerodynamic]]ally, ornithopters differ from [[fixed wing aircraft]] in that the driving airfoils have a reciprocating, rather than rotary, motion.
+Aerodynamically, ornithopters differ from fixed wing aircraft in that the driving airfoils have a reciprocating, rather than 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 may produce both lift and thrust, drag-inducing structures are minimized. These two advantages may allow ornithopters to achieve a high degree of efficiency in flight.
-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.
+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.
-== In fiction ==
-* In the movie ''[[Ghost in the Shell 2: Innocence]]'' the characters used an ornithopter to visit the ocean city.
-*The ornithopter (called "'Thopter") is familiar to readers of [[Frank Herbert]] as the primary means of on-planet travel by the wealthy inhabitants of the [[Dune universe]].  This is a theme also carried into the [[Dune computer and video games|Dune computer games]]: ''[[Dune (video game)|Dune]]'', ''[[Dune II]]'', ''[[Dune 2000]]'', ''[[Emperor: Battle for Dune]]'', and ''[[Frank Herbert's Dune]]''. Oddly, in neither the ''Dune'' movie nor the SciFi channel TV miniseries were the 'thopters depicted with flapping wings. The 'thopters in the original movie didn't even have wings at all. The '[[Dune Encyclopedia]]' entry on the 'thopter depicts them as being powered by giant, airbreathing, bivalve shelled animals.
-*Ornithopters are also mentioned in the book ''[[Norstrilia]]'' by [[Cordwainer Smith]]. This is one of many similarities between ''[[Norstrilia]]'' and ''[[Dune (novel)|Dune]]''.
-*In ''[[The Brother's War]]'', a novel based on [[Magic: The Gathering]], the fictional characters [[Urza]] and [[Mishra (Magic: The Gathering)|Mishra]] used ornithopters invented by the Thran to move between places. Recent [[flavor text]]s for the Ornithopter states that, regardless of plane, artificers always 'invent' Ornithopters first. The game also contains a card representing an ornithopter as a flying artifact creature.  Some early rules texts for the game (from around the period of ''[[Revised (Magic: The Gathering)|Revised]]'') include the humorous line in small text near the end: "We apologize to anyone that has been killed by an ornithopter," in reference to the Ornithopter's natural inability to deal damage. Finally, variations of the ornithopter have been introduced in the game.
-*Ornithopter-like craft called "moths" are carried aboard [[LEXX|the ''Lexx'']] and can travel in air or space.
-*In Robert Heinlein's novel ''[[The Number of the Beast (novel)|Number of the Beast]]'', ornithopters are used for long-distance travel by the Russian and British colonists of an alternate-universe Mars.
-*Ornithopters are a means of transportation used by the Dark Empire in ''[[The History of the Runestaff]]'' series of novels by [[Michael Moorcock]].
-*The retro film ''[[Sky Captain and the World of Tomorrow]]'' features ornithopters in [[dog fight]]s against fixed-wing aircraft.
-*The fantasy novels ''[[Airborn (novel)]]'' and ''[[Skybreaker (novel)]]'' by [[Kenneth Oppel]] use ornithopters as short-distance flying machines.
-*Ornithopters are featured in ''[[Star Wars: Revenge of the Sith]]'', as a means of transportation on the [[Wookiee]] homeworld, [[Kashyyyk]].
-*In [[Hayao Miyazaki]]'s interpretation of the [[Diana Wynne Jones]] book, the film ''[[Howl's Moving Castle (film)|Howl's Moving Castle]]'', all the flying craft are ornithopters, although they are not referred to as such. The craft range from the smaller, which have two wings which flap like a hummingbirds, to the larger military craft that have 14 main wings and multiple smaller wings all flapping in concert.
-*Ornithopters have also appeared in two other shorts done by [[Studio Ghibli]] that have been shown at [[Studio Ghibli Museum]]'s [[Saturn Theatre]].
-*''[[Imaginary Flying Machines]]'' is an animated short about the various contraptions dreamed up by people over the ages, which includes ornithopters. Directed, written and narrated by [[Hayao Miyazaki]].
-*''[[The Ornithopter Story: Fly to the Sky Hiyodiro Tengu!]]'', is a short documentary about the efforts of [[Hiyodiro Tengu]], a famous model airplane maker, to build a remote controlled model ornithopter.
 ==References==
@@ Line 61: / Line 54: @@
 {{commonscat|Ornithopter}}
 * [http://www.ornithopter.org The Ornithopter Zone web site]
+* [http://www.ornithopter.org/slideshow/01.htm Slide show introduction to ornithopters]
 * [http://www.ornithopter.ca University of Toronto ornithopter project]
 * [http://www.flightgear.org/ Fly the Ornithopter yourself with the OpenSource flightsimulator FlightGear]
@@ Line 71: / Line 65: @@
 * [http://www.atmitchell.com/journeys/history/aviation/hargrave.cfm Lawrence Hargrave's ornithopters - State Library of NSW]
-[[Category:Dune]]
 [[Category:Aircraft]]