Glossary of boomerang terms

The glossary is broken into the following sections:

Some glossary items are courtesy of Clay Dawson, Rich “The Boomerang Man” Harrison, and the now-defunct ‘Mothers Against Boomerangs’ web-site.

COMPETITION

centre circle (bulls-eye)
The two-metre radius circle from which the boomerang is thrown in most events. It is worth ten accuracy points in the Accuracy and Aussie Round events.
centre pin
The point around which all Accuracy and distance circles are centred
circle judge
Official who determines if a foot fault has occurred, in an event other than Distance
Consecutive Catch
An event largely superseded by improved boomerang technology; originally run as a knock-out competition, in the time before dozens of catches in a row became commonplace…
Consecutive Catch with Increased Difficulty
A precursor to the current Trick Catch event, but run as a knock-out event. Commonly, the first two throws required any kind of catch: then two with the non-throwing hand, two with the throwing hand, two behind the back, two foot catches, and then, if multiple throwers remained, a Nearest the Pin throw-off.
Doubling
Refers to either the second part of the Trick Catch/Doubling event, or the older event where two (or more) boomerangs were thrown simultaneously from the same hand, with simple catches of both boomerangs required.
foot fault
When a thrower fails to keep both feet within the nominated throwing area until they have released their boomerang. The feet should be entirely behind the line (or within the circle).
German Doubling
The same as the Doubling part of the modern Trick Catch event, but the two boomerangs may be thrown separately. The second boomerang must be thrown before the first returns.
GLORP
The boomerang equivalent of the basketball game HORSE. Developed by California’s Team Gel, one thrower (the Dominator) nominates a type of trick catch (it does not need to be one of the ten standard trick catches; imagination and daring is part of this game). If they make the catch, all other throwers, in order, must make the same catch, or they earn a letter. Earn all five letters — GLORP — and a thrower is out. No type of trick catch can be nominated twice in a row. If the Dominator drops, the next thrower in order becomes the new Dominator, and the old Dominator goes to the end of the queue. If the Dominator makes a catch, but it is not the nominated Trick Catch, they go to the end of the queue, and then the first thrower to make the nominated Trick Catch becomes the new Dominator (if no one makes the catch, treat it as if it were a drop, with the second thrower becoming the new Dominator).
head spotter
Official placed in the middle of the field ultimately responsible for determining range in the Distance event

Hunting stick

Hunting Stick
Event using a non-returning hunting stick (not a boomerang) to hit a target. Three throws are provided at each range (ten metres, twenty metres, thirty metres, and so on). Throwers progress to the next stage if they hit the target within their three throws.
Juggling
Event where two or more boomerangs are thrown alternately. One boomerang must be in the air at all time, and the goal is to make as many catches as possible in succession.
Largest Boomerang
Event where the aim is to make an accuracy throw of an established standard with the boomerang with the largest size (usually measured tip to tip). You may need a wingspan of over a metre to win this!
line judge (base line steward)
Official in the Distance event who determines if a foot fault has occurred
Nearest the Pin
Now usually completed as part of the Accuracy event, the winner is the thrower whose return lands closest to the centre pin. Note that the distance is measured from the nearest point of the boomerang — so landing a boomerang “around” the centre pin is not as good as landing actually on the centre pin.
One Hand Catching
Obsolete predecessor to the Consecutive Catch with Increased Difficulty and Trick Catch events
pole judge
Official in the Distance event who determines if the returning boomerang passes inside, or outside, the poles
range spotter
Official standing near range lines to determine if a boomerang made range or, in the Distance event, a person who tracks the boomerang until it reaches its furthest range, and then holds that position until the head spotter determines the maximum range. During the Distance event, these range spotters stand to the sides of the throwing alley.
Same Boomerang
A style of tournament where throwers must nominate a boomerang and use it for every event (an exception is often made for the MTA event, if it is included)
Smallest Boomerang
Per the Largest Boomerang event, but at the other extreme! Try to get under a 10cm span.
Suicide
A variation of an event, in which many throwers throw simultaneously within the same area. Originally this was mainly used for the Consecutive Catch competition, but it can be adapted to most events to add some fun chaos.
SuperCatch
A teams event where one thrower makes an MTA throw, and everyone else makes as many Fast Catch throws and catches while the MTA is in the air. One point is awarded for each catch (including catching the MTA). As with normal MTA, however, if the MTA is not caught, no score is made… While Team SuperCatch is far more popular, individual SuperCatch, where one thrower flings the MTA, makes the fast catch throws, and then catches the MTA, is also possible (but bloody difficult!)
throwing alley
The V-shaped area of the field in which Distance boomerangs are thrown. Only the head spotter should be in this area.
throw-off
One or more throws made after an event to separate equal-scoring competitors

GEOMETRY

aerofoil (airfoil in the USA)

The parts of a boomerang

The cross-sectional shape of a wing. It primarily determines the amount of lift and drag a boomerang generates.
ambidextrous
A boomerang with aerofoils that makes it throwable either right or left-handed
angle of attack (AoA)
The amount of twist in a wing; a positive angle of attack sees the bottom of the wing pointing slightly in the direction of rotation. A significant portion of the lift of a boomerang arises from angle of attack, including the built-in geometric angle of attack. Reduced angle of attack is sometimes referred to as ‘washout’.
anhedral (negative dihedral)
The angle that a given wing slopes downwards from the elbow (ie. is bent down)
concave
The carving-out of a boomerang’s lower side is a common technique to increase drag and keep a boomerang’s flight low
dihedral
The angle that a given wing slopes upwards from the elbow (ie. is bent up)
elbow (centre)
The connecting point of the wings of a boomerang. The term centre is generally used for boomerangs with three, or more, wings.
flap (spoiler)
Typically made with duct tape, a flap adds drag to a boomerang, and is a quick and easy way to adapt to stronger winds than a given boomerang would usually cope with, or to slow the spin of a boomerang. Typically a flap is 10-20 mm in width, and 1-15 mm in height. Placing a flap nearer the end of a wing will have a greater effect than placing it nearer the elbow. Somewhat contradictorily, placing a flap close to the trailing edge can, like a spoiler on a car, cause downforce at that point, thus increasing the angle of attack and therefore resulting in a boomerang that flies higher. Other placements commonly adopted are trailing in the plane of the wing, or at the centre of multi-blade boomerangs to stabilise their descent.
geometric angle of attack
The angle of attack created by the shape of the wings, before any further twisting is done by the thrower; for example, the undercutting of the leading edge on a fast catch boomerang creates a notable geometric angle of attack.
hole
A hole creates a high amount of drag. Like a flap, a hole has more effect further from the centre of rotation (ie. at the tips of wings). It may make a whistling sound during flight.
leading edge
The edge of a given wing that, while spinning, initially cuts through the air
leading wing (lifting wing, control wing)
The wing of a given boomerang that, when spinning, leads the trailing wing by cutting through the air first
polyhedral
Where the dihedral of a given wing changes over its length. This is generally a more accurate description than dihedral of the tuning of a wing, as the bulk of the wing may be flat, and only the tip bent upwards. This distinction is quite notable when tuning an MTA, for example.
semi-crude aerofoil

Modern Boomerang Aerofoil, Semi-Crude

Describes a relatively blunt wing profile that has been found to work for a variety of shapes and sizes of modern boomerangs. The relatively blunt leading edge results in a lower spin rate and a shorter hover, therefore making the boomerang easier to catch and more accurate. Sometimes referred to with the acronym MBA-SC (Modern Boomerang Aerofoil, Semi-Crude).

sweep
Either forward or reverse, this describes whether a wing arcs toward the direction of rotation (forward) or away from it (reverse). This affects the rate at which a boomerang lays over. Generally, a fast catch boomerang will have swept-forward wings, while a trick-catch boomerang will have swept-backward wings.
tips
The ends of the wings furthest from the elbow
trailing edge
The edge of a given wing that does not directly cut through the air
trailing wing (dingle wing)
The wing that trails the leading wing as it spins. The ‘dingle’ term was coined by Lorin Hawes, an American who settled in Queensland.
turbulator
A part of a aerofoil designed to break up the smooth flow of air around it, a la the dimples found on golf balls
undercut
Used both as a verb and a noun, this refers to removal of material on the underside of a wing to provide more, or less, drag and lift. Most commonly this is seen on the underside of the leading edge of a wing, in order to improve lift.
velcro
Most commonly used via adhesive dots, this can be used to create substantial drag. The fuzzy half of velcro is used; the hooks half could be interpreted as a “catching aid” during competition.
warp
Unwanted twisting of a boomerang, primarily due to poor storage. A contrast to tune in that warp is rarely a positive term.
weight (ballast)
Can be in the form of taped-on coins, lead tape, or embedded as a permanent part of the boomerang. Weight added to a boomerang can greatly change its flight pattern. Weight generally adds stability, especially in wind. Weight located near the tips most notably increases the rotational momentum of the boomerangs, and is a common method to increase the range of a boomerang. Weight added to the leading arm helps keep the boomerang low and slows down the rate of layover, which can help in windy conditions.
wing (arm, blade)
The part of a boomerang primarily responsible for generating lift. Wings join at the elbow. The term blade is used almost exclusively for boomerangs with three (or more) wings.

MATERIALS

ABS
A type of plastic for making boomerangs that is denser than wood and polypropylene, but less dense than phenolic. It is harder and more brittle than wood, polypropylene and phenolic. Most commonly a milky-white colour.
aircraft grade
Refers to a high-quality grade of plywood. It has stricter controls on voids in the layers and on the surface, and may rotate adjacent layers of ply by 45° rather than 90° (resulting in a stiffer composite material).
aluminium
While metal boomerangs are not allowed in competition, this material has been used for creating a number of boomerangs
Baltic birch
Often considered the minimum standard for creating quality boomerangs, baltic birch typically has layers approximately 1 mm thick. It is considerably cheaper than Finnish birch.
carbon fibre
A very stiff composite material used for a variety of boomerangs, including MTAs. It is pitch black in colour.
cyalume
A chemical that absorbs light and slowly releases it. Used for illuminating boomerangs thrown at night. Most commonly available in capsules, it has a relatively short life (several hours) once activated. Freezing the capsule pauses the deterioration of the chemical for a week or so, allowing it to be used on multiple occasions.
fibreglass
A stiff and dense material, but difficult to work and thus make boomerangs out of. Fibreglass tape and resin is a common combination used to repair a broken boomerang.
Finnish birch
A high-grade quality of plywood, typically with 2 plys per mm
G-10
A composite of phenolic and fibreglass
LED
A Light-Emitting Diode. These are commonly used for illuminating boomerangs thrown at night, as LEDs emit a relatively bright light for the small amount of power they consume. Increasingly, they are combined with electrical circuits that allow simple, or very complex, patterns of flashing on and off. This extends battery life and can create stunning effects when spinning during flight.
lexan
A polycarbonate plastic that is quite stiff. It is normally translucent.
marine plywood
Plywood in which the glue is waterproof. The actual wood is no more waterproof than that of non-marine plywood.
paxolin (paper phenolic, pax)
A very popular composite material for making boomerangs, made of layers of paper bonded with phenolic resin. This material is denser than wood, yet durable and easily tuned.
PET
The plastic used for drink bottles. In thicker sections it is stiff and easy to work.
phenolic resin (bakelite)
A stiff and dense plastic, usually combined with layers of paper (paxolin), or a linen such as cotton
ply
An individual thin layer of wood in a plywood
plywood
A wood and glue composite with thin layers of wood that have the grain aligned at alternating angles to create a much stiffer material than is available with a natural section of wood
polypropylene
A relatively soft plastic that comes in various colours. The “stress relieved” version is used for boomerangs. It is most commonly known as the material used by the Tri-Fly boomerangs made by American Eric Darnell.
strip laminate

Strip-laminated boomerang

A construction method involving thin layers of wood adhered perpendicular to the plane of the boomerang (ie. along the length of the wings), as opposed to in the plane of the boomerang (as in plywood). Primarily done for aesthetic reasons.

SCIENCE

asymmetrical lift
Lift is created by the movement of air around wings. It is dependent on the wing shape and the speed of the air. The speed of the air passing by a wing is determined primarily by two components: the boomerang’s rate of spin, and whether that spin coincides with the direction the boomerang, as a whole, is moving through the air. At one position, the speed due to spin coincides with the speed due to the flight of the boomerang. At the other extreme, the speed due to rotation somewhat cancels the speed due to the flight of the boomerang. The different air speeds over different wings leads to different lift: hence, asymmetrical lift. This lift leads to gyroscopic precession.
Beaufort
A unit indicating wind intensity, based on a scale named after Admiral Sir Francis Beaufort. A low Beaufort number indicates little or no wind, and a high number means higher wind. Beaufort numbers are NOT directly tied to given speeds. Boomerangs can be thrown in the 0-5 Beaufort range, but it’s not much fun beyond about 3 or 4 (very approximately 15 km/hr). Beaufort number 12 (a hurricane) means trees are uprooted, and your limp, lifeless body flies farther than your boomerang (which does not return to you).
Bernoulli’s Principle
States that air travelling at a higher speed generates less pressure than air travelling at a lower speed. A boomerang aerofoil forces the air at the top to move further within the same time, and therefore faster. This creates upwards lift.
drag
The retarding force on a boomerang moving through the air. The greater the drag, the quicker a boomerang will slow both translationally and rotationally. This may, or may not, be an advantage depending on the purpose of a boomerang, and the conditions it is thrown in.
gyroscopic precession
Any spinning object, including a boomerang, is subject to gyroscopic precession. In summary, and avoiding an awful lot of maths, this means that any attempt to move a spinning object (eg. by the lift created by a boomerang’s aerofoil) is translated at right angles to the original input. Gyroscopie precession is what causes a boomerang to return.
gyroscopic stability
The tendency of a spinning object to continue spinning on its axis, while resisting any force that attempts to change that axis. This is why a moving bicycle is so much more easy to keep upright than a still one. Gyroscopic stability evens out the asymmetrical lift effects that occur as the boomerang spins, thus preventing a wobbling flight.
lift
The force “upwards” on a boomerang, at right angles to the plane the boomerang is spinning within

THROWING

death spiral
A common form of unstable descent for a boomerang, especially for an MTA or Trick Catch boomerang, where the boomerang descends in a wide arc, or circle, at a rapid rate
elliptical (tear-drop)
A flight pattern that is long and narrow, as opposed to round
floater
A boomerang throw that flies high
full grip (cradle grip, wraparound grip)

Full grip

To hold the boomerang with a tip against the palm and at least one finger acting as a “trigger” on the trailing edge of the boomerang. Most often used for larger or heavier boomerangs. Some boomerangs have a notch carved into them to accommodate this kind of grip.

hackey
Hitting a boomerang into the air with a body part, normally the foot, prior to catching it
humpback throw (triangular throw)
A style of throw commonly used to counteract strong winds, where the boomerang is thrown with little or even negative layover, high and more off the wind. It peaks early, sweeps down and then rises to a second peak, before returning to the thrower. When thrown with lesser force, this is sometimes referred to as “surfing the wind”.
laying over (laying down)
The process of a boomerang, during flight, moving from spinning on a vertical plane to spinning on a horizontal plane
layover (see also sidearm)
The angle at which the plane of the boomerang is angled from vertical when throwing. A boomerang thrown tilted towards the thrower is said to have ‘negative layover’, or be ‘oververtical’.
molechaser
A low circular flight
pinch grip (pincer grip)

Pinch grip

Holding the boomerang between the thumb and the side of the index finger. This generally gives the ability to impart more spin than with the full grip, and is therefore more favoured.

sandwich catch (pancake catch)
The most common, and generally effective, method of catching a boomerang: between flat palms
separation
The time difference between the flight of a pair of trick catch boomerangs during the Trick Catch/Doubling event; the greater the separation, the easier the second catch will be to make
sidearm
An alternate term, common in the USA, for layover. “Throwing sidearm” can also be used to indicate a throw with 90° layover.
tune
To twist or bend a boomerang to achieve a desired shape, and therefore flight path, under a given set of conditions
WELSH
An acronym coined by American Pat Steigman. It describes a method of describing a given throw. The five characteristics that can be controlled by the thrower are the angle with respect to the wind (W), the elevation of the throw (E), the amount of layover (L), the amount of spin (S) and the hardness of the throw (H). For example, a description of throwing a fast catch boomerang might be W:90° E:0° L:0° S:high H:high. An Accuracy throw might be W:60° E:10° L:20° S:low H:medium.
window
Either an imaginary target in front of the thrower where a successful throw will pass through (a rang that takes a very precise throw is said to require a narrow window), or the gap formed at the centre of a spinning boomerang. The latter is not generally an issue with multi-blade boomerangs, where there will always be part of the boomerang at this centre point.

TYPES

admiral’s hat
A variation on the omega shape, as named and popularised by models by Australian Bunny Read and American Rusty Harding
clunker
A heavy, or crudely aerofoiled, boomerang with little lift. Most often chosen when throwing in heavy wind conditions.
cross-stick
A four-wing boomerang, most commonly formed by connecting two straight sections
doublers
Two boomerangs designed, or paired, to return when thrown together from the same hand. They should do so with sufficient separation to allow both to be caught.
fuzzy

Fuzzy boomerang

A sharply asymmetrical two-wing shape, with each wing having an abrupt bend at mid-length
hockey stick
Term for an MTA boomerang in the shape of an “L”
hook
A style of two-blade boomerang roughly resembling an actual hook, generally characterized by a distinctive asymmetry in wing length or shape, or a wing that curves in towards the centre of rotation. Hooks generally have the greatest potential as long-distance boomerangs. The ‘King Billy’ hook, created around 1850 and still existing, is probably the most famous individual boomerang in the world.
insider
The boomerang from a pair of Trick Catch/Doubling boomerangs that returns first
keyhole
A two-winged boomerang with a very acute angle at the elbow
lap joint
A boomerang created by joining two separately-constructed wings at the elbow. Primarily used for aesthetic reasons.
lefty
A left-handed boomerang. This is a mirror image of a right-handed boomerang, and travels clockwise rather than counter-clockwise. Also refers to a left-handed thrower.
MTA
Short for Maximum Time Aloft, a boomerang designed to stay in the air for as long as possible. Thin and light, and typically markedly asymmetrical with two wings, they are one of the hardest types of boomerang to create, tune and throw well. They do not necessarily return to the same spot they were thrown from.
multi-blader (radial)
A generic term for a boomerang with three, or more, wings
omega
A boomerang resembling the Greek character of the same name, with a curved elbow and flared-out tips
outsider
The boomerang from a pair of Trick Catch/Doubling boomerangs that returns last
pinwheel
A boomerang with six or more wings, typically constructed by connecting straight sections at the centre with a bolt
quad-blader (quad)
A boomerang with four wings
running man
A tri-blader with wavy arms resembling the legs and torso of a person running
snake
Snake MTAA MTA shape resembling a snake, as popularised by German Ola Wahlberg. These tend to achieve greater initial height than most other types of MTAs.
traditional
A boomerang with an angle of approximately 110° between its two wings. This angle was not chosen because of its efficiency in flight, but rather because it is, via tree roots, one of the few ways to reliably get a section of natural bent wood with the grain running along the full length of the boomerang.
tri-blader
A boomerang with three arms/blades
vee
A common shape for modern boomerangs, having two wings separated by less than 90°, with a relatively pointed elbow, and therefore in the shape of a “V”

ALL THE REST

boomerang (rang, boom, returner, B, stick)
To be a boomerang, a stick must tend to return as a result of gyroscopic precession caused by asymmetric lift. The lift is created as a result of a throw that gives the object rotation and linear motion. The word was adopted from the Turuwal people of New South Wales (the term ‘bou-mar-rang’ was first documented in 1822). There were many other names for boomerangs, and hunting sticks, used elsewhere in Australia. Boomerangs were not used by Aborigines in Tasmania, or in the central and northern sections of the country. Approximately 60% of Aborigines used boomerangs and hunting sticks; a further 10% used hunting sticks only; and the remainder used neither.
hunting stick (throwing stick, throwstick, killing stick, kylie)
A non-returning weapon for hunting or warfare. It is typically much larger and straighter than a returning boomerang, and is thrown sidearm (ie. with 90° layover).
MHR
Acronym for ‘Many Happy Returns’, name of the newsletter of the United States Boomerang Association (USBA), and a common closing tag-line for throwers
rad
Primarily in the USA, a term of high approval
rippah
Primarily in the USA, a term describing a good throw. Basically, a misspelling of the Australian slang term ‘ripper’

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