Aerodynamic returning boomerang
|Country or region||Australia|
|World Games||1989 (invitational)|
A boomerang is a thrown tool, typically constructed as a flat airfoil, that is designed to spin about an axis perpendicular to the direction of its flight. A returning boomerang is designed to return to the thrower. It is well known as a weapon used by Indigenous Australians for hunting.
An airfoil or aerofoil is the cross-sectional shape of a wing, blade, or sail.
Indigenous Australians are the Aboriginal and Torres Strait Islander peoples of Australia, descended from groups that existed in Australia and surrounding islands before British colonisation. The time of arrival of the first Indigenous peoples on the continent and nearby islands is a matter of debate among researchers. The earliest conclusively human remains found in Australia are those of Mungo Man LM3 and Mungo Lady, which have been dated to around 50,000 years BP. Recent archaeological evidence from the analysis of charcoal and artefacts revealing human use suggests a date as early as 65,000 BP. Luminescence dating has suggested habitation in Arnhem Land as far back as 60,000 years BP. Evidence of fires in South-West Australia suggest 'human presence in Australia 120,000 years ago', although more research is required. Genetic research has inferred a date of habitation as early as 80,000 years BP. Other estimates have ranged up to 100,000 years and 125,000 years BP.
Boomerangs have been historically used for hunting, as well as sport and entertainment. They are commonly thought of as an Australian icon,and come in various shapes and sizes.
The University of Queensland estimates that Australia has around 300,000 active hunters investing $556,650,000 annually into the Australian economy.
Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the largest country in Oceania and the world's sixth-largest country by total area. The neighbouring countries are Papua New Guinea, Indonesia, and East Timor to the north; the Solomon Islands and Vanuatu to the north-east; and New Zealand to the south-east. The population of 26 million is highly urbanised and heavily concentrated on the eastern seaboard. Australia's capital is Canberra, and its largest city is Sydney. The country's other major metropolitan areas are Melbourne, Brisbane, Perth, and Adelaide.
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A boomerang is a throwing stick with certain aerodynamic properties, traditionally made of wood, but boomerang-like devices have also been made from bones. Modern boomerangs used for sport may be made from plywood or plastics such as ABS, polypropylene, phenolic paper, or carbon fibre-reinforced plastics. Boomerangs come in many shapes and sizes depending on their geographic or tribal origins and intended function. Many people think of a boomerang as the Australian type, although today there are many types of more easily usable boomerangs, such as the cross-stick, the pinwheel, the tumble-stick, the Boomabird, and many other less common types.
The throwing stick or throwing club is a wooden rod with either a pointed tip or a spearhead attached to one end, intended for use as a weapon. A throwing stick can be either straight or roughly boomerang-shaped, and is much shorter than the javelin. It became obsolete as slings and bows became more prevalent, except on the Australian continent, where the native people continued refining the basic design. Throwing sticks shaped like returning boomerangs are designed to fly straight to a target at long ranges, their surfaces acting as airfoils. When tuned correctly they do not exhibit curved flight, but rather they fly on an extended straight flight path. Straight flight ranges greater than 100 meters have been reported by historical sources as well as in recent research.
Aerodynamics, from Greek ἀήρ aer (air) + δυναμική (dynamics), is the study of motion of air, particularly as interaction with a solid object, such as an airplane wing. It is a sub-field of fluid dynamics and gas dynamics, and many aspects of aerodynamics theory are common to these fields. The term aerodynamics is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis for the development of heavier-than-air flight and a number of other technologies. Recent work in aerodynamics has focused on issues related to compressible flow, turbulence, and boundary layers and has become increasingly computational in nature.
Acrylonitrile butadiene styrene (ABS) (chemical formula (C8H8)x·(C4H6)y·(C3H3N)z) is a common thermoplastic polymer. Its glass transition temperature is approximately 105 °C (221 °F). ABS is amorphous and therefore has no true melting point.
An important distinction should be made between returning boomerangs and non-returning boomerangs. Returning boomerangs fly and are examples of the earliest heavier-than-air human-made flight. A returning boomerang has two or more airfoil wings arranged so that the spinning creates unbalanced aerodynamic forces that curve its path so that it travels in an ellipse, returning to its point of origin when thrown correctly. While a throwing stick can also be shaped overall like a returning boomerang, it is designed to travel as straight as possible so that it can be aimed and thrown with great force to bring down the game. Its surfaces are therefore symmetrical and not with the aerofoils that give the returning boomerang its characteristic curved flight.
In mathematics, an ellipse is a plane curve surrounding two focal points, such that for all points on the curve, the sum of the two distances to the focal points is a constant. As such, it generalizes a circle, which is the special type of ellipse in which the two focal points are the same. The elongation of an ellipse is measured by its eccentricity e, a number ranging from e = 0 to e = 1.
The most recognisable type of the boomerang is the L-shaped returning boomerang; while non-returning boomerangs, throwing sticks (or kylies) were used as weapons, returning boomerangs have been used primarily for leisure or recreation. Returning boomerangs were also used to decoy birds of prey, thrown above the long grass to frighten game birds into flight and into waiting nets. Modern returning boomerangs can be of various shapes or sizes.
The origin of the term is mostly certain, but many researchers have different theories on how the word entered into the English vocabulary. One source asserts that the term entered the language in 1827, adapted from an extinct Aboriginal language of New South Wales, Australia, but mentions a variant, wo-mur-rang, which it dates to 1798.The boomerang was first encountered by western people at Farm Cove (Port Jackson), Australia, in December 1804, when a weapon was witnessed during a tribal skirmish:
New South Wales is a state on the east coast of Australia. It borders Queensland to the north, Victoria to the south, and South Australia to the west. Its coast borders the Tasman Sea to the east. The Australian Capital Territory is an enclave within the state. New South Wales' state capital is Sydney, which is also Australia's most populous city. In March 2019, the population of New South Wales was over 8 million, making it Australia's most populous state. Just under two-thirds of the state's population, 5.1 million, live in the Greater Sydney area. Inhabitants of New South Wales are referred to as New South Welshmen.
Farm Cove is a tidal inlet and shallow bay in Sydney Harbour, separated from Sydney Cove by Bennelong Point. Known to the indigenous inhabitants of Sydney as Woccanmagully, Farm Cove was used by them as an initiation ground and for the "Kangaroo and Dog Dance".
Port Jackson, consisting of the waters of Sydney Harbour, Middle Harbour, North Harbour and the Lane Cove and Parramatta Rivers, is the ria or natural harbour of Sydney, New South Wales, Australia. The harbour is an inlet of the Tasman Sea. It is the location of the Sydney Opera House and Sydney Harbour Bridge. The location of the first European settlement and colony on the Australian mainland, Port Jackson has continued to play a key role in the history and development of Sydney.
... the white spectators were justly astonished at the dexterity and incredible force with which a bent, edged waddy resembling slightly a Turkish scimytar, was thrown by Bungary, a native distinguished by his remarkable courtesy. The weapon, thrown at 20 or 30 yards [18 or 27 m] distance, twirled round in the air with astonishing velocity, and alighting on the right arm of one of his opponents, actually rebounded to a distance not less than 70 or 80 yards [64 or 73 m], leaving a horrible contusion behind, and exciting universal admiration.— The Sydney Gazette and New South Wales Advertiser, 23 December 1804
David Collins listed "Wo-mur-rāng" as one of eight aboriginal "Names of clubs" in 1798.but was probably referring to the Woomera, which is actually a spear thrower. A 1790 anonymous manuscript on aboriginal language of New South Wales reported "Boo-mer-rit" as "the Scimiter".
In 1822, it was described in detail and recorded as a "bou-mar-rang" in the language of the Turuwal people (a sub-group of the Darug) of the Georges River near Port Jackson. The Turawal used other words for their hunting sticks but used "boomerang" to refer to a returning throw-stick.
Boomerangs were, historically, used as hunting weapons, percussive musical instruments, battle clubs, fire-starters, decoys for hunting waterfowl, and as recreational play toys. The smallest boomerang may be less than 10 centimetres (4 in) from tip to tip, and the largest over 180 cm (5.9 ft) in length. Tribal boomerangs may be inscribed or painted with designs meaningful to their makers. Most boomerangs seen today are of the tourist or competition sort, and are almost invariably of the returning type. Depictions of boomerangs being thrown at animals, such as kangaroos, appear in some of the oldest rock art in the world, the Indigenous Australian rock art of the Kimberly region, which is potentially up to 50,000 years old. Stencils and paintings of boomerangs also appear in the rock art of West Papua, including on Bird's Head Peninsula and Kaimana, likely dating to the Last Glacial Maximum, when lower sea levels led to cultural continuity between Papua and Arnhem Land in Northern Australia. The oldest surviving Australian Aboriginal boomerangs come from a cache found in a peat bog in the Wyrie Swamp of South Australia and date to 10,000 BC.
Although traditionally thought of as Australian, boomerangs have been found also in ancient Europe, Egypt, and North America. There is evidence of the use of non-returning boomerangs by the Native Americans of California and Arizona, and inhabitants of southern India for killing birds and rabbits.Some boomerangs were not thrown at all, but were used in hand to hand combat by Indigenous Australians. Ancient Egyptian examples, however, have been recovered, and experiments have shown that they functioned as returning boomerangs. Hunting sticks discovered in Europe seem to have formed part of the Stone Age arsenal of weapons. One boomerang that was discovered in Obłazowa Cave in the Carpathian Mountains in Poland was made of mammoth's tusk and is believed, based on AMS dating of objects found with it, to be about 30,000 years old. In the Netherlands, boomerangs have been found in Vlaardingen and Velsen from the first century BC. King Tutankhamun, the famous Pharaoh of ancient Egypt, who died over 3,300 years ago, owned a collection of boomerangs of both the straight flying (hunting) and returning variety.
No one knows for sure how the returning boomerang was invented, but some modern boomerang makers speculate that it developed from the flattened throwing stick, still used by the Australian Aborigines and other indigenous peoples around the world, including the Navajo in North America. A hunting boomerang is delicately balanced and much harder to make than a returning one. The curving flight characteristic of returning boomerangs was probably first noticed by early hunters trying to "tune" their throwing sticks to fly straight.
It is thought by some that the shape and elliptical flight path of the returning boomerang makes it useful for hunting birds and small animals, or that noise generated by the movement of the boomerang through the air, or, by a skilled thrower, lightly clipping leaves of a tree whose branches house birds, would help scare the birds towards the thrower. It is further supposed by some that this was used to frighten flocks or groups of birds into nets that were usually strung up between trees or thrown by hidden hunters.In southeastern Australia, it is claimed that boomerangs were made to hover over a flock of ducks; mistaking it for a hawk, the ducks would dive away, toward hunters armed with nets or clubs.
Traditionally, most boomerangs used by aboriginal groups in Australia were 'non-returning'. These weapons, sometimes called "throwsticks" or "kylies", were used for hunting a variety of prey, from kangaroos to parrots; at a range of about 100 metres (330 ft), a 2-kg (4.4 lb) non-returning boomerang could inflict mortal injury to a large animal. A throwstick thrown nearly horizontally may fly in a nearly straight path and could fell a kangaroo on impact to the legs or knees, while the long-necked emu could be killed by a blow to the neck.[ citation needed ] Hooked non-returning boomerangs, known as "beaked kylies", used in northern Central Australia, have been claimed to kill multiple birds when thrown into a dense flock. Throwsticks are used as multi-purpose tools by today's aboriginal peoples, and besides throwing could be wielded as clubs, used for digging, used to start friction fires, and are sonorous when two are struck together.
Today, boomerangs are mostly used for recreation. There are different types of throwing contests: accuracy of return; Aussie round; trick catch; maximum time aloft; fast catch; and endurance (see below). The modern sport boomerang (often referred to as a 'boom' or 'rang') is made of Finnish birch plywood, hardwood, plastic or composite materials and comes in many different shapes and colours. Most sport boomerangs typically weigh less than 100 grams (3.5 oz), with MTA boomerangs (boomerangs used for the maximum-time-aloft event) often under 25 grams (0.9 oz).
Boomerangs have also been suggested as an alternative to clay pigeons in shotgun sports, where the flight of the boomerang better mimics the flight of a bird offering a more challenging target.
The modern boomerang is often computer-aided designed with precision airfoils. The number of "wings" is often more than 2 as more lift is provided by 3 or 4 wings than by 2.
In 1992, German astronaut Ulf Merbold performed an experiment aboard Spacelab that established that boomerangs function in zero gravity as they do on Earth. French Astronaut Jean-François Clervoy aboard Mir repeated this in 1997.In 2008, Japanese astronaut Takao Doi again repeated the experiment on board the International Space Station.
Beginning in the later part of the twentieth century, there has been a bloom in the independent creation of unusually designed art boomerangs. These often have little or no resemblance to the traditional historical ones and on first sight some of these objects may not look like boomerangs at all. The use of modern thin plywoods and synthetic plastics have greatly contributed to their success. Designs are very diverse and can range from animal inspired forms, humorous themes, complex calligraphic and symbolic shapes, to the purely abstract. Painted surfaces are similarly richly diverse. Some boomerangs made primarily as art objects do not have the required aerodynamic properties to return.
A returning boomerang is a rotating wing. It consists of two or more arms, or wings, connected at an angle; each wing is shaped as an airfoil section. Although it is not a requirement that a boomerang be in its traditional shape, it is usually flat.
Boomerangs can be made for right or left handed throwers. The difference between right and left is subtle, the planform is the same but the leading edges of the aerofoil sections are reversed. A right-handed boomerang makes a counter-clockwise, circular flight to the left while a left-handed boomerang flies clockwise to the right. Most sport boomerangs weigh between 70 to 110 grams (2.5 to 3.9 oz), have a wingspan of 250 to 350 millimetres (9.8 to 13.8 in) and a range of between 20 and 40 m (22 and 44 yd).
A falling boomerang starts spinning, and most then fall in a spiral. When the boomerang is thrown with high spin, a boomerang flies in a curved rather than a straight line. When thrown correctly, a boomerang returns to its starting point. As the wing rotates and the boomerang moves through the air, the airflow over the wings creates lift on both "wings". However, during one-half of each blade's rotation, it sees a higher airspeed, because the rotation tip-speed and the forward speed add, and when it is in the other half of the rotation, the tip speed subtracts from the forward speed. Thus if thrown nearly upright each blade generates more lift at the top than the bottom.While it might be expected that this would cause the boomerang to tilt around the axis of travel, because the boomerang has significant angular momentum, the gyroscopic precession causes the plane of rotation to tilt about an axis that is 90 degrees to the direction of flight causing it to turn. When thrown in the horizontal plane, as with a Frisbee, instead of in the vertical, the same gyroscopic precession will cause the boomerang to fly violently, straight up into the air and then crash.
Fast Catch boomerangs usually have three or more symmetrical wings (seen from above), whereas a Long Distance boomerang is most often shaped similar to a question mark.Maximum Time Aloft boomerangs mostly have one wing considerably longer than the other. This feature, along with carefully executed bends and twists in the wings help to set up an 'auto-rotation' effect to maximise the boomerang's hover-time in descending from the highest point in its flight.
Some boomerangs have turbulators—bumps or pits on the top surface that act to increase the lift as boundary layer transition activators (to keep attached turbulent flow instead of laminar separation).
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Boomerangs are generally thrown in treeless, large open spaces that are twice as large as the range of the boomerang, the flight direction, left or right will depend upon the boomerang, not the thrower. A right-handed or left-handed boomerang can be thrown with either hand, but throwing a boomerang with the wrong hand requires a throwing motion that many throwers may find awkward. The following technique applies to a right-handed boomerang, the directions are reversed for a left-handed boomerang.
A properly thrown boomerang should curve around to the left, climb gently, level out in mid-flight, arc around and descend slowly, and then finish by popping up slightly, hovering, then stalling near the thrower. Ideally, this momentary hovering or stalling will allow the catcher the opportunity to clamp their hands shut horizontally on the boomerang from above and below, sandwiching the centre between their hands.
The boomerang is thrown held between finger and thumb at the bottom end, in a near-vertical position, with the upper aerofoil section to the outside of the thrower and the 'hook' of the boomerang facing forward so as to present the leading edges of the aerofoils to the slipstream when spinning.
The boomerang is aimed directly into, or 3 to 5 degrees right, of the wind, and the flight then takes it left through the "eye of the wind" and finally returning downwind. The accuracy of the throw starts with an understanding of the weight and aerodynamics of that particular boomerang and the strength and direction of the wind; from this, the thrower chooses the precise angle of tilt of the boomerang from vertical, the angle against the wind and the strength of the throw. The stronger the wind, the softer the boomerang is thrown and the less the tilt off vertical. The boomerang can be made to return without the aid of any wind but the wind speed and direction must be taken into account. A light wind of three to five miles per hour is considered ideal. If the wind is strong enough to fly a kite, then it may be too strong for a given boomerang.
A great deal of trial and error is required to perfect the throw over time. Different boomerang designs have different flight characteristics and are suitable for different conditions.
A World Record achievement was made on 3/6/07 by Tim Lendrum in Aussie Round. Tim scored 96 out of 100, giving him a National Record as well as an equal World Record throwing an "AYR" made by expert boomerang maker Adam Carroll from ONE Boomerangs formerly Real Boomerangs.
In international competition, a world cup is held every second year. As of 2017 [update] , teams from Germany and the United States dominated international competition. The individual World Champion title was won in 2000, 2002, 2004, 2012 and 2016 by Swiss thrower Manuel Schütz. In 1992, 1998, 2006 and 2008 Fridolin Frost from Germany won the title.
The team competitions of 2012 and 2014 were won by Boomergang (an international team). World champions were Germany in 2012 and Japan in 2014 for the first time. Boomergang was formed by individuals from several countries, including the Colombian Alejandro Palacio. In 2016 USA became team world champion.
Modern boomerang tournaments usually involve some or all of the events listed below 20 metres (66 ft) from the thrower. Throwing takes place individually. The thrower stands at the centre of concentric rings marked on an open field.In all disciplines the boomerang must travel at least
|Accuracy 100||99 points||2007|
|Aussie Round||99 points||2007|
|Fast Catch||14.07 s||2017|
|Trick Catch/Doubling||533 points||2009|
|Consecutive Catch||2251 catches||2009|
|MTA 100||139.10 s||2010|
|MTA unlimited||380.59 s||2010|
|Long Distance||238 m||1999|
Non-discipline record: Smallest Returning Boomerang: Sadir Kattan of Australia in 1997 with 48 millimetres (1.9 in) long and 46 millimetres (1.8 in) wide. This tiny boomerang flew the required 20 metres (22 yd), before returning to the accuracy circles on 22 March 1997 at the Australian National Championships.
A boomerang was used to set a Guinness World Record with a throw of 427.2 metres (1,402 ft) by David Schummy on 15 March 2005 at Murrarie Recreation Ground, Australia. This broke the record set by Erin Hemmings who threw an Aerobie 406.3 metres (1,333 ft) on 14 July 2003 at Fort Funston, San Francisco.
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Long-distance boomerang throwers aim to have the boomerang go the furthest possible distance while returning close to the throwing point. In competition the boomerang must intersect an imaginary surface defined as an infinite vertical projection of a 40-metre (44 yd) line centred on the thrower. Outside of competitions, the definition is not so strict, and throwers may be happy simply not to walk too far to recover the boomerang.
Long-distance boomerangs are optimised to have minimal drag while still having enough lift to fly and return. For this reason, they have a very narrow throwing window, which discourages many beginners from continuing with this discipline. For the same reason, the quality of manufactured long-distance boomerangs is often non-deterministic.
Today's long-distance boomerangs have almost all an S or ? – question mark shape and have a beveled edge on both sides (the bevel on the bottom side is sometimes called an undercut). This is to minimise drag and lower the lift. Lift must be low because the boomerang is thrown with an almost total layover (flat). Long-distance boomerangs are most frequently made of composite material, mainly fibre glass epoxy composites.
The projection of the flight path of long-distance boomerang on the ground resembles a water drop. For older types of long-distance boomerangs (all types of so-called big hooks), the first and last third of the flight path are very low, while the middle third is a fast climb followed by a fast descent. Nowadays, boomerangs are made in a way that their whole flight path is almost planar with a constant climb during the first half of the trajectory and then a rather constant descent during the second half.
From theoretical point of view, distance boomerangs are interesting also for the following reason: for achieving a different behaviour during different flight phases, the ratio of the rotation frequency to the forward velocity has a U-shaped function, i.e., its derivative crosses 0. Practically, it means that the boomerang being at the furthest point has a very low forward velocity. The kinetic energy of the forward component is then stored in the potential energy. This is not true for other types of boomerangs, where the loss of kinetic energy is non-reversible (the MTAs also store kinetic energy in potential energy during the first half of the flight, but then the potential energy is lost directly by the drag).
In Noongar language, kylie is a flat curved piece of wood similar in appearance to a boomerang that is thrown when hunting for birds and animals."Kylie" is one of the Aboriginal words for the hunting stick used in warfare and for hunting animals. Instead of following curved flight paths, kylies fly in straight lines from the throwers. They are typically much larger than boomerangs, and can travel very long distances; due to their size and hook shapes, they can cripple or kill an animal or human opponent. The word is perhaps an English corruption of a word meaning "boomerang" taken from one of the Western Desert languages, for example, the Warlpiri word "karli".
A wing is a type of fin that produces lift, while moving through air or some other fluid. As such, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift.
A fixed-wing aircraft is a flying machine, such as an airplane or aeroplane, which is capable of flight using wings that generate lift caused by the aircraft's forward airspeed and the shape of the wings. Fixed-wing aircraft are distinct from rotary-wing aircraft, and ornithopters. The wings of a fixed-wing aircraft are not necessarily rigid; kites, hang gliders, variable-sweep wing aircraft and airplanes that use wing morphing are all examples of fixed-wing aircraft.
Hawks are a group of medium-sized diurnal birds of prey of the family Accipitridae. Hawks are widely distributed and vary greatly in size.
A spear-thrower, spear-throwing lever or atlatl is a tool that uses leverage to achieve greater velocity in dart-throwing, and includes a bearing surface which allows the user to store energy during the throw.
A club is among the simplest of all weapons: a short staff or stick, usually made of wood, wielded as a weapon since prehistoric times. There are several examples of blunt-force trauma caused by clubs in the past, including at the site of Nataruk in Turkana, Kenya, described as the scene of a prehistoric conflict between bands of hunter-gatherers 10,000 years ago. In popular culture, clubs are associated with primitive cultures, especially cavemen.
Knife throwing is an art, sport, combat skill, or variously an entertainment technique, involving an artist skilled in the art of throwing knives, the weapons thrown, and a target. In some stage performances, the knife thrower ties an assistant to the target, and throws to miss them.
An Aerobie is a flying ring used in a manner similar to a chakram or flying disc (Frisbee), for recreational catches between two or more individuals. Its ring shape of only about 3 mm (0.12 in) thickness makes the Aerobie lighter and more stable in flight than a disc. It can be bent to tune it for straighter flight. Since it has very low drag and good stability, it can be thrown much farther than a flying disc. The Aerobie was used to set two former world records for thrown objects.
A paper plane, paper aeroplane (UK), paper airplane (US), paper glider, paper dart or dart is a toy aircraft, usually a glider made out of folded paper or paperboard.
Darts are missile weapons, designed to fly such that a sharp, often weighted point will strike first. They can be distinguished from javelins by fletching and a shaft that is shorter and/or more flexible, and from arrows by the fact that they are not of the right length to use with a normal bow.
In aeronautics and aeronautical engineering, camber is the asymmetry between the two acting surfaces of an aerofoil, with the top surface of a wing commonly being more convex. An aerofoil that is not cambered is called a symmetric aerofoil. The benefits of cambering were discovered and first utilized by George Cayley in the early 19th century.
A number of animals have evolved aerial locomotion, either by powered flight or by gliding. Flying and gliding animals have evolved separately many times, without any single ancestor. Flight has evolved at least four times, in the insects, pterosaurs, birds, and bats. Gliding has evolved on many more occasions. Usually the development is to aid canopy animals in getting from tree to tree, although there are other possibilities. Gliding, in particular, has evolved among rainforest animals, especially in the rainforests in Asia where the trees are tall and widely spaced. Several species of aquatic animals, and a few amphibians and reptiles have also evolved to acquire this gliding flight ability, typically as a means of evading predators.
A valari is a weapon made up of iron, and this specific variant is used primarily by the Tamil people of the Indian subcontinent. The valari is used for protecting cattle from predators, war and hunting. It was the favourite weapon of choice in deer hunting. It is the predecessor of the wooden boomerang, which was used widely in India since the Upper Paleolithic, most notably in the Deccan plains by kingdoms for war.
A woomera is a wooden Australian Aboriginal spear-throwing device. Similar to an atlatl, it serves as an extension of the human arm, enabling a spear to travel at a greater speed and force than possible with only the arm.
An amentum was a leather strap attached to a javelin used in ancient Greek athletics, hunting, and warfare, which helped to increase the range and the stability of the javelin in flight. Stability in flight was important because it allowed the javelin to land on its point, which was the only way the throw could be accurately recorded in competition or be useful against a live target. The amentum also increased the effective length of the throwing arm as does a spear-thrower and so enhanced speed.
Hunting weapons are weapons designed or used primarily for hunting game animals for food or sport, as distinct from defensive weapons or weapons used primarily in warfare.
Gliding flight is heavier-than-air flight without the use of thrust; the term volplaning also refers to this mode of flight in animals. It is employed by gliding animals and by aircraft such as gliders. This mode of flight involves flying a significant distance horizontally compared to its descent and therefore can be distinguished from a mostly straight downward descent like with a round parachute.
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