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Insect flight, In the past several million years, flying insects have evolved with amazing flight characteristics and abilities. In many ways, they are still far superior to anything mankind has created. Even our understanding of the aerodynamics of flexible, flapping wings and how insects fly is imperfect. The most obvious application of this research is the engineering of low Reynolds number, extremely small Micro Air Vehicles. Image File history File linksMetadata Download high resolution version (1216x970, 244 KB) Description A dragonfly perches on a twig in the afternoon sun. ...
Image File history File linksMetadata Download high resolution version (1216x970, 244 KB) Description A dragonfly perches on a twig in the afternoon sun. ...
{{dablink Hey guh dragonfly (disambiguation). ...
Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets...
Flight is the process of flying: either movement through the air by aerodynamically generating lift or aerostatically using buoyancy, or movement beyond earths atmosphere by spacecraft. ...
Aerodynamics is a branch of fluid dynamics concerned with the study of gas flows, first analysed by George Cayley in the 1800s. ...
A Laughing Gull on the beach in Atlantic City. ...
The Reynolds number is the most important dimensionless number in fluid dynamics and provides a criterion for determining dynamic similitude. ...
The term micro air vehicle (MAV) refers to a new breed of remotely controlled aircraft (UAV) that are significantly smaller than similar craft obtainable with the current state of the art. ...
Evolution and purpose Some time in the Carboniferous Period, when there were only two major land masses, insects began flying. This was 350 million years ago. The earliest flyers were similar to dragonflies with two sets of wings. Most insects today, which evolved from those first flyers, have simplified down to either one pair of wings or two pairs functioning as a single pair. Natural selection has played an enormous role in refining the wings, control and sensory systems, and anything else that effects aerodynamics or kinematics. One noteworthy trait is wing twist. Most insect wings are twisted, like helicopter blades, with a higher angle of attack at the base. The twist is generally between 10 and 20 degrees. Some insects evolved other wing features that are not advantageous for flight but play a role in something else like mating. These traits are noteworthy, but not important to this article. Most insects control their wings by adjusting tilt, stiffness, and flapping frequency of the wings through tiny muscles in the thorax. The Carboniferous is a major division of the geologic timescale that extends from the end of the Devonian period, about 340 million years ago (mya), to the beginning of the Permian period, about 280 mya. ...
Natural selection is the metaphor Charles Darwin used in 1859 to name the process he postulated to drive the adaptation of organisms to their environments and the origin of new species. ...
A control system is a device or set of devices that manage the behavior of other devices. ...
(See also sense) A sensory system is a part of the nervous system that consists of sensory receptors, neural pathways, and those parts of the brain responsible for processing the information. ...
In physics, kinematics is the branch of mechanics concerned with the motions of objects without being concerned with the forces that cause the motion. ...
It has been suggested that Copulation be merged into this article or section. ...
Tilt can refer to any of the following: Tilt - a punk rock band Tilt - a British progressive house act Tilt - a Finnish video game magazine Tilt - an American television series, with poker as a backdrop, produced by ESPN Tilt - a condition that can occur to players at a poker table...
Stiffness is the resistance of an elastic body to deflection by an applied force. ...
This article is being considered for deletion in accordance with Wikipedias deletion policy. ...
Diagram of a tsetse fly, showing the head, thorax and abdomen The thorax is a division of an animals body that lies between the head and the abdomen. ...
Insects, occupying the biological niches that they do, need to be incredibly maneuverable. They must find their food in tight spaces and be capable of escaping larger predators. The maneuverability, in an aerodynamic viewpoint, is shown through high lift and thrust forces. Typical insect flyers can attain lift forces up to three times their weight and horizontal thrust forces up to five times their weight. The vortices that explain these forces are described below.
Basic mechanics There are two basic methods of insect flight. The first is a fling and clap method. Most insects, however, use a method that creates a spiraling leading edge vortex. It is the latter method which will be the focus. These flapping wings move through two basic half-strokes. The downstroke starts up and back and is plunged downward and forward. Then the wing is quickly flipped over, supination, so that the leading edge is pointed backwards. The upstroke then pushes the wing upward and backward. Then the wing is flipped again, pronation, and another downstroke can occur. The frequency range is typically 5 to 200 hertz. When the insect is hovering, the two strokes take the same amount of time. A slower downstroke, however, provides thrust. 1967 Model Cessna 182K in flight showing after-market vortex generators on the wing leading edge A vortex generator is an aerodynamic surface, basically a small vane, that creates a vortex. ...
In human and zoological anatomy (sometimes called zootomy), several terms are used to describe the location of organs and other structures in the body of bilateral animals. ...
In human and zoological anatomy (sometimes called zootomy), several terms are used to describe the location of organs and other structures in the body of bilateral animals. ...
The hertz (symbol: Hz) is the SI unit of frequency. ...
Thrust is a reaction force described quantitatively by Newtons Second and Third Law. ...
Identification of major forces is critical to understanding insect flight. The first attempts to understand flapping wings assumed a quasi-steady state. This means that the flow over the wing at any given time was assumed to be the same as how the flow would be over a non-flapping, steady-state wing at the same angle of attack. By dividing the flapping wing into a large number of motionless positions and then analyzing each position, it would be possible to create a timeline of the instantaneous forces on the wing at every point in time. The calculated lift was too small by a factor of three, so there must be unsteady phenomena providing aerodynamic forces. There were several developing analytical models attempting to approximate flow close to a flapping wing. Some researchers predicted force peaks at supination. With a dynamically scaled model of a fruit fly, these predicted forces were later confirmed. Others argued that the force peaks during supination and pronation are caused by an unknown rotational effect that is fundamentally different from the translational phenomena. There is some disagreement with this argument. Through computational fluid dynamics, some researchers argue that there is no rotational effect. They claim that the high forces are caused by an interaction with the wake shed by the previous stroke. Binomial name Drosophila melanogaster Meigen, 1830 Drosophila melanogaster Meigen , 1830 (Black-bellied Dew-lover) a dipteran (two-winged) insect, is the species of fruit fly that is commonly used in genetic experiments; it is among the most important model organisms. ...
Computational fluid dynamics (CFD) is the use of computers to analyze problems in fluid dynamics. ...
Similar to the rotational effect mentioned above, the phenomena associated with flapping wings are not completely understood or agreed upon. Because every model is an approximation, different models leave out effects that are assumed to be negligible. For example, the Wagner effect says that circulation rises slowly to its steady-state due to viscosity when an inclined wing is accelerated from rest. This phenomenon would explain a lift value that is less than what is predicted. Typically, the case has been to find sources for the added lift. It has been argued that this effect is negligible for flow with a Reynolds number that is typical of insect flight. The Wagner effect was consciously ignored in at least one recent model.
One of the most important phenomena that occurs during insect flight is leading edge suction. This force is significant to the calculation of efficiency. The concept of leading edge suction was first put forth to describe vortex lift on sharp edged delta wings. At high angles of attack, the flow separates over the leading edge but reattaches before reaching the trailing edge. Within this bubble of separated flow is a vortex. Because the angle of attack is so high, there is a lot of momentum transferred downward into the flow. These two features create a large amount of lift force as well as some additional drag. The important feature, however, is the lift. Because the flow has separated, yet it still provides large amounts of lift, this phenomenon is called “delayed stall.” This effect was observed in flapping insect flight, and it was proven to be capable of providing enough lift to account for the deficiency in the quasi-steady state models. All of the effects on a flapping wing can be reduced to three major sources of aerodynamic phenomena: the leading edge vortex, the steady-state aerodynamic forces on the wing, and the wing’s contact with its wake from previous strokes.
The size of flying insects ranges from about 20 micrograms to about 3 grams. As body mass increases, wing area increases and wing beat frequency decreases. For larger insects, the Reynolds number (Re) can be as high as 10000. For smaller insects, it can be as low as 10. This means that viscous effects are much more important to the smaller insects, although the flow is still laminar, even in the largest flyers.
Another interesting feature of insect flight is the body tilt. As flight speed increases, the body tends to tilt nose-down and more horizontal. This reduces the frontal area and therefore the body drag. Since drag also increases as forward velocity increases, the insect is making its flight more efficient as this efficiency becomes more necessary. Additionally, by changing the geometric angle of attack on the downstroke, the insect is able to keep its flight at an optimal efficiency through as many maneuvers as possible.
The development of general thrust is relatively small compared with lift forces. Lift forces can be more than three times the insect’s weight, while thrust at even the highest speeds can be as low as 20% of the weight. This force is developed primarily through the less powerful upstroke of the flapping motion.
The other method of flight, fling and clap, functions differently. In this process, the wings clap together above the insect’s body and then fling apart. As they fling open, the air gets sucked in and creates a vortex over each wing. This bound vortex then moves across the wing and, in the clap, acts as the starting vortex for the other wing. By this method, circulation and thus lift are increased to the extent of being higher, in most cases, than the typical leading edge vortex method. One of the reasons this method is not employed by more insects is the expected damage and wear to the wings caused by the repeated clapping.
Current research Scientists study insect flight for a variety of reasons: biological development and understanding of the animals, a purely scientific interest in unsteady aerodynamics, or the engineering interest to develop Micro Air Vehicles (MAVs) or similar devices. The most obvious and, arguably the most useful application is Micro Air Vehicles. Based on the size of the MAV, different flight methods make more sense. Currently, most MAVs are larger than insects and fly at Reynolds numbers closer to bird flight. For this reason, they are generally rotorcraft or use fixed wings and propellers. For a smaller MAV flying at a smaller Reynolds number, the flight mechanics of insects become attractive. Additionally, MAVs that are the size of insects can accomplish a number of tasks that larger vehicles cannot.
In 1993 the RAND Corporation determined that the development of insect size flying and crawling systems were possible and could give the United States a significant military advantage. In 1996, DARPA funded research into MAVs through the Small Business Innovation Research program. At this time, it was concluded that a six inch MAV was feasible and capable of performing extremely useful missions. The history of this field of research is very suggestive of its future applications. A successful MAV could be used for search and rescue, military or law enforcement surveillance, or chemical or biological agent detection. The primary use, however, would probably be reconnaissance in confined spaces. Alternate meanings: See RAND (disambiguation) The RAND Corporation is an American think tank first formed to offer research and analysis to the U.S. military. ...
The Defense Advanced Research Projects Agency (DARPA) is an agency of the United States Department of Defense responsible for the development of new technology for use by the military. ...
The potential benefits of MAVs are extremely promising. Possible uses include detection of poisons and drugs or search and rescue in burning buildings or after natural disasters. These uses have no foreseeable negative consequences for anyone but the individuals whose jobs these machines could replace. Some things that an MAV could do are obviously destructive. Small explosives or chemical/biological agents could be delivered to a precise location for assassination attempts or any number of missions that would be dangerous for a soldier. The existence of MAVs means that soldiers do not need to risk their lives. At the same time, however, these missions directly result in the deaths or casualties of enemies. Other military applications are reconnaissance and surveillance. With the changing nature of warfare, precise urban tactics require reliable intelligence to minimize civilian casualties and property damage. In this sense, more and better information to troops is a good thing if these military actions will be occurring anyway. Will more intelligence encourage more missions?
The idea of military reconnaissance segues into the potential use of MAVs for police surveillance. Perhaps this technology could help prosecute criminals, but it is also a frightening issue of privacy. If high quality video can be captured inside a home by a machine that looks and behaves like a fly, then no place is safe from the eye of the law. What will the legal precedent be for a warrant? There is a serious issue of how much probable cause is necessary before police could use such a technology. In the spirit of the PATRIOT Act, will people feel that their right to privacy has been violated? All told, the benefits of scientific knowledge and potential to save lives outweigh the possible negative consequences of this technology which are decades ahead anyway. This article needs cleanup. ...
See also The term micro air vehicle (MAV) refers to a new breed of remotely controlled aircraft (UAV) that are significantly smaller than similar craft obtainable with the current state of the art. ...
Unmanned Aerial Vehicle over Iraq. ...
Orders Subclass Apterygota Symphypleona - globular springtails Subclass Archaeognatha (jumping bristletails) Subclass Dicondylia Monura - extinct Thysanura (common bristletails) Subclass Pterygota Diaphanopteroidea - extinct Palaeodictyoptera - extinct Megasecoptera - extinct Archodonata - extinct Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Blattodea (cockroaches) Mantodea (mantids) Isoptera (termites) Zoraptera Grylloblattodea Dermaptera (earwigs) Plecoptera (stoneflies) Orthoptera (grasshoppers, crickets...
Flight is the mode of locomotion used by most of the world’s bird species. ...
References 1. Camper, M.A., “An Insect’s Role in the Development of Micro Air Vehicles,” Colorado State University, 2003.
2. Dickinson, M.H., Lehmann, F.O., and Sane, S.P., “Wing Rotation and the Aerodynamic Basis of Insect Flight,” Science Magazine Vol. 284, June 1999.
3. Ellington, C.P., van der Berg, C., Willmott, A.P. and Thomas, A.L.R., “Leading Edge Vortices in Insect Flight,” Nature, Vol. 384, p. 626-630, 1996.
4. Ellington, C.P., “The aerodynamics of hovering insect flight,” Philosophical Transactions Royal Society of London B305, 1984.
5. Ellington, C.P., “The novel aerodynamics of insect flight: applications to micro-air vehicles,” The Journal of Experimental Biology 202, 3439-3448, 1999.
6. Grasmeyer, J.M. and Keennon, M.T., “Development of the Black Widow Micro Air Vehicle,” AIAA Paper No. 2001-0127, 2001.
7. Haj-Hariri, H., “Unsteady Aerodynamics of Flapping Wings,” University of Virginia, 2001.
8. Lewin, G.C., Haj-Hariri, H., “Modeling thrust generation of a two-dimensional heaving airfoil in a viscous flow,” Journal of Fluid Mechanics, Vol. 492, 2003.
9. Lighthill, M.J., “On the Weis-Fogh mechanism of lift generation,” Journal of Fluid Mechanics, Vol. 60, p 1-17, 1973.
10. Platzer, Max F., Department Chairman, “Aerodynamics and Aeroelasticity: Flapping-Wing Propulsion.” Last revised 2005, Retrieved 1 November 2005, from http://www.aa.nps.navy.mil/programs/aero/propulsion/
11. Polhamus, E.C., “A Concept of the Vortex Lift of Sharp-Edge Delta Wings Based on a Leading-Edge-Suction Analogy,” Langley Research Center, 1966.
12. Pringle, J.W.S., “Insect flight,” Oxford Biology Readers, Vol. 52, 1975.
13. Sane, S.P., “The aerodynamics of insect flight,” The Journal of Experimental Biology, Vol. 206, p. 4191-4208, August 2003.
14. Savage, S.B., Newman, B.G. and Wong, D.T.M., “The role of vortices and unsteady effects during the hovering flight of dragon flies,” The Journal of Experimental Biology, Vol. 83, p. 59-77, 1979.
15. Van den Berg, C., Ellington, C.P., “The vortex wake of a hovering model hawk moth,” Philosophical Transactions Royal Society of London, Vol. 352, p. 317-328, 1997.
16. Walker, J.A., “Rotational lift: something difference or more of the same?,” The Journal of Experimental Biology, Vol. 205, p. 3783-3792, September 2002.
17. Walker, P.B., “Growth of circulation about a wing and an apparatus for measuring fluid motion,” Reports and Mem., Aeronaut. Res. Com. no. 1402, 1931.
18. Zbikowski, R., “On aerodynamic modeling of an insect-like flapping wing in hover for micro air vehicles,” The Royal Society, January 2002.
External links http://www.colostate.edu/Depts/Entomology/courses/en507/papers_2003/camper.pdf http://www.rmcs.cranfield.ac.uk/daps/guidance/microairvehicles/view http://jeb.biologists.org/cgi/reprint/202/23/3439.pdf http://www.cs.washington.edu/homes/diorio/MURI2003/Publications/sane_review.pdf |
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