Boomerang

A boomerang is a tool, typically constructed as a flat airfoil that, when thrown, 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.

Boomerangs have been historically used for hunting, as well as a sport, and entertainment. They are commonly thought of as an Australian icon,^[1] and come in various shapes and sizes.

Description

A boomerang is traditionally a long wooden device, although historically boomerang-like devices have also been made from bones. Modern boomerangs used for sport are often made from thin aircraft plywood, plastics such as ABS, polypropylene, phenolic paper, or even high-tech materials such as 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 tumblestick, the boomabird and many other less common types.

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 man-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 elliptical path and returns 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 therefore are symmetrical and not uneven like the aerofoils which give the returning boomerang its characteristic curved flight.

The most recognizable type of the boomerang is the returning boomerang; while non-returning boomerangs, throwing sticks (or shaunies) 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 as can be seen in a photo in the Modern use section.

Historical evidence also points to the use of non-returning boomerangs by the Native Americans of California and Arizona, and inhabitants of southern India for killing birds and rabbits.^[2] Indeed, some boomerangs were not thrown at all, but were used in hand to hand combat by Indigenous Australians.^[3] Ancient Egyptian examples, however, have been recovered, and experiments have shown that they functioned as returning boomerangs.^[4]

Boomerangs can be variously 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.^[5] Tribal boomerangs may be inscribed and/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.

Etymology

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.^[6] 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:^[7]

... 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.^[8] A 1790 anonymous manuscript on aboriginal language of New South Wales reported "Boo-mer-rit" as "the Scimiter".^[9]

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.^[10] They were also mistakenly referred to as a "woomerang" in confusion with the Aboriginal spear-throwing device called "woomera".

History

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.^[11] 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.^[12] 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 BP.

Though traditionally thought of as Australian, boomerangs have been found also in ancient Europe, Egypt, and North America. Hunting sticks discovered in Europe seem to have formed part of the Stone Age arsenal of weapons.^[13] One boomerang that was discovered in Jaskinia Obłazowa 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.^[14][15] 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.^[13]

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.^[13]

Modern use

Today, boomerangs are mostly used as sporting items. 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.^[16]

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.^[17][18]

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.^[19] In 2008, Japanese astronaut Takao Doi again repeated the experiment on board the International Space Station.^[20][21]

Hunting

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.^[22] 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.^[1] Despite these notions and similar claims by a few European writers, there is no independently contemporaneous record of any aboriginal peoples using a returning boomerang as a weapon.

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.^[1] 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. 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. It should be noted that 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.

Design

A returning boomerang is a rotating wing. Though it is not a requirement that the boomerang be in its traditional shape, it is usually flat. 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 curve rather than a straight line. When thrown correctly, a boomerang returns to its starting point.

Returning boomerangs consist of two or more arms, or wings, connected at an angle. Each wing is shaped as an airfoil.

As the wing rotates and the boomerang moves through the air, this creates airflow over the wings and this 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.^[23]

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, gyroscopic effect causes the plane of rotation to tilt about an axis that is 90 degrees to the direction of flight, and this is what curves the flight in such a way that it will tend to return.^[23]

Thus gyroscopic precession is what makes the boomerang return to the thrower when thrown correctly. This is also what makes the boomerang fly straight up into the air when thrown incorrectly. With the exception of long-distance boomerangs, they should not be thrown sidearm or like a Frisbee, but rather thrown with the long axis of the wings rotating in an almost-vertical plane.

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.^[24] 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).

Modern construction

The pattern is placed on the plywood so that the wood grain runs across from the tip of one end of the boomerang to the tip of the other end. Try to get the grain of the outer ply running at 45 degrees to the length of the arms. If there is any warp in the wood, make sure that this produces dihedral on the upper side of the boomerang, i.e., if the airfoil is uppermost and the boomerang is on a flat surface, then the wingtips are raised slightly above the surface. (Any anhedral and the boomerang won't fly.) The pattern is traced on to the boomerang with a pencil. The boomerang shape is cut out of the plywood. This basic cut out is called the blank. An outline is drawn on the top of the blank to show the areas to be shaped for the leading and trailing edges of the wings. The profiles of the wings are shaped. The top of the leading edge of each wing is decreased at a 45° angle, while the rear of the wing is angled down to leave 1–2 mm thick trailing edge. The bottom face of the leading edge is trimmed back slightly. The tips of the wings are shaped down to the same thickness as the trailing edge. The various layers of the plywood serve as an outline that helps the worker achieve equal slopes. A shallow section may also be cut out from the bottom surface of each wing. For example, this might consist of a 5-cm long strip near the wing tip and behind the leading edge. Using progressively finer sandpaper, the surface of the boomerang is smoothed carefully. Check the boomerang for a slight amount of dihedral (2–3 mm) on both wings at this point. If there isn't any, introduce some by heating the boomerang either over a heat source or a brief spell in the microwave oven (about 30 seconds on high) – if the boomerang is just about uncomfortably hot to handle, you've got it just about right. Bend up the tips of the wings and place the boomerang on a flat surface with a coin under each tip and a weight (bag of sugar?) on the elbow of the boomerang. Allow it to cool for twenty minutes or more. After spraying the surface with sanding sealer, the surface is smoothed with fine steel wool. The boomerang is then painted again.

Tuning the flight

The boomerang is then thrown several times to check if it works. The extreme subtleties of the aerodynamic forces on the light wooden boomerang make it surprisingly difficult to predict how the finished boomerang will perform. Two apparently identical boomerangs may radically differ in their flight patterns. For example, they may climb uncontrollably, they may fall repeatedly into the ground, they may exhibit long narrow pattern non-returning flight, or display other erratic behaviour. The only sure way to know is to flight-test them. There are several methods to correct problems, for example the wing profiles might be adjusted by additional sanding. Plywood boomerangs may be heated for a short time in a microwave oven which softens the glue between the layers and then can be carefully intentionally warped. Angle of attack of the leading arm and the dingle arm can be adjusted, as can the overall dihedral angle of the wings all with some effect. There are many other esoteric tuning techniques as well. Tuning boomerangs is more of a slowly learned art than a science. The quality of the boomerang is also checked throughout this process. A tuned boomerang should be stored carefully on a flat surface away from too much humidity, direct sunlight, or heat. These conditions can subtly affect the shape of the boomerang and ruin its flight characteristics, and the boomerang will then need to be re-tuned.

The hunting boomerang is more delicately balanced and is therefore much harder to make than a returning one. When thrown, this type of boomerang needs to develop no unbalanced aerodynamic forces that would affect its flight path, so that it will fly true to the target.

Art renaissance

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 often do not look like boomerangs at all. The use of modern thin plywoods and synthetic plastics have greatly contributed to their success. As long as there are somewhere in the object several airfoil contoured surfaces, whether wing shaped or not, these boomerangs can be thrown and will return. Designs are amazingly 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.

Throwing technique

A right-handed boomerang is thrown with a counter-clockwise spin causing a counter-clockwise flight (as seen from above). Conversely, a left-handed boomerang is constructed as a mirror image with the aerofoils' leading edges on the left side of the wings, as seen from above, causing it to produce lift when circling clockwise. Although appearing symmetrical from a plan view, the leading edges are on opposite edges of the wings (leading and trailing) so as to present the leading edges of the aerofoil to the wind when spinning.

Most sport boomerangs are in the range of about 70 to 110 grams (2.5 to 3.9 oz). The range on most is between 20 and 40 m (22 and 44 yd). Boomerangs are generally thrown in treeless, large open spaces that are twice as large as the range of the boomerang. A right- or left-handed boomerang can be thrown with either hand, but the flight direction will depend upon the boomerang, not the thrower. Throwing a boomerang with the wrong hand requires a throwing motion that many throwers may find awkward.

The correct launch orientation makes the boomerang's flight begin by flying into the wind, then having its flight take it through the "eye of the wind" and finally returning downwind using the wind's speed to help complete its flight back to the thrower. It is the spin that makes the boomerang return and the strength of throw and spin must be varied according to the speed of the wind – the stronger the wind, the less power is required to provide lift enough to make the return journey. In other words, the stronger the wind, the softer the boomerang is thrown. 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 is usually too strong for boomerangs.

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.

Competitions and records

In international competition, a world cup is held every second year. As of 2017, 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.

Competition disciplines

Modern boomerang tournaments usually involve some or all of the events listed below^[25] In all disciplines the boomerang must travel at least 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.

Events include:

• Aussie Round: considered by many to be the ultimate test of boomeranging skills. The boomerang should ideally cross the 50-metre (160 ft) circle and come right back to the centre. Each thrower has five attempts. Points are awarded for distance, accuracy and the catch.
• Accuracy: points are awarded according to how close the boomerang lands to the centre of the rings. The thrower must not touch the boomerang after it has been thrown. Each thrower has five attempts. In major competitions there are two accuracy disciplines: Accuracy 100 and Accuracy 50.
• Endurance: points are awarded for the number of catches achieved in 5 minutes.
• Fast Catch: the time taken to throw and catch the boomerang five times. The winner has the fastest timed catches.
• Trick Catch/Doubling: points are awarded for trick catches behind the back, between the feet, and so on. In Doubling the thrower has to throw two boomerangs at the same time and catch them in sequence in a special way.
• Consecutive Catch: points are awarded for the number of catches achieved before the boomerang is dropped. The event is not timed.
• MTA 100 (Maximal Time Aloft, 100 metres (328 ft)): points are awarded for the length of time spent by the boomerang in the air. The field is normally a circle measuring 100 m. An alternative to this discipline, without the 100 m restriction is called MTA unlimited.
• Long Distance: the boomerang is thrown from the middle point of a 40-metre (130 ft) baseline. The furthest distance travelled by the boomerang away from the baseline is measured. On returning, the boomerang must cross the baseline again but does not have to be caught. A special section is dedicated to LD below.
• Juggling: as with Consecutive Catch, only with two boomerangs. At any given time one boomerang must be in the air.

World records

As of June 2010

Discipline	Result	Name	Year	Tournament
Accuracy 100	99 points	Alex Opri	2007	Viareggio
Aussie Round	99 points	Fridolin Frost	2007	Viareggio
Endurance	81 catches	Manuel Schütz	2005	Milan
Fast Catch	14.60 s	Adam Ruhf	1999	Emmaus
Trick Catch/Doubling	533 points	Manuel Schütz	2009	Bordeaux
Consecutive Catch	2251 catches	Haruki Taketomi	2009	Japan
MTA 100	139.10 s	Nick Citoli	2010	Rome
MTA unlimited	380.59 s	Billy Brazelton	2010	Rome
Long Distance	238 m	Manuel Schütz	1999	Kloten

Guinness World Record - Smallest Returning Boomerang

Non-discipline record: Smallest Returning Boomerang: Sadir Kattan of Australia in 1997 with 1.9 inches (48 mm) long and 1.8 inches (46 mm) wide. This tiny boomerang flew the required 22 yards (20 m), before returning to the accuracy circles on 22 March 1997 at the Australian National Championships.^[26]

Guinness World Record - Longest Throw of Any Object by a Human

A boomerang was used to set a Guinness World Record with a throw of 1,401.5 feet (427.2 metres) by David Schummy on 15 March 2005 at Murrarie Recreation Ground, Australia.^[27] This broke the record set by Erin Hemmings who threw an Aerobie 1,333 feet (406.3 metres) on 14 July 2003 at Fort Funston, San Francisco.^[28]

Long-distance versions

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 extrude of a 40-metre (44 yd) large line centred on the thrower. Outside of competitions, the definition is not so strict, and the thrower is happy whenever he/she does not have to travel 50 metres (55 yd) after the throw, to recover the boomerang.

General properties

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.

Flight path

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).

Related terms

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^[29] "Kylie" is one of the Aboriginal words for the hunting stick used in warfare and for hunting animals.^[30] 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".

See also

• Batarang
• Captain Boomerang
• Chakram
• Commonwealth Boomerang, a World War II fighter-plane
• Frisbee
• Shuriken
• Throwing stick
• Valari

References

Further reading

• Boomerang Ask.com Design, Throwing, Flight Path.
• Yutaka Nishiyama, Instructions of Paper Boomerangs in 70 Languages, Flight of paper boomerang
• Boomerang
• Valde-Nowak et al. (1987). "Upper Palaeolithic boomerang made of a mammoth tusk in south Poland". Nature 329: 436-438 (1 October 1987); doi:10.1038/329436a0.

External links

Wikimedia Commons has media related to Boomerangs.

Look up boomerang in Wiktionary, the free dictionary.

• International Federation of Boomerang Associations
• History of Boomerangs
• Unspinning the Boomerang, The Maths and Physics of a Boomerang
• Boomerang aerodynamics an online dissertation
• Explanation of the origin of the word 'Boomerang'
• How to Throw a Boomerang
• How to Throw Boomerangs
• Australian Boomerang Shooting
• How to Throw a Boomerang Videos
•  Chisholm, Hugh, ed. (1911). "Boomerang". Encyclopædia Britannica (11th ed.). Cambridge University Press. 
• BoomerangArchive's channel on YouTube