Boomerang

( Original Source : Wikipedia Encyclopedia, Photo Source : Google Images )

A boomerang is a simple wooden implement used for various purposes. It is primarily attributed to Australian Aborigines, but other forms are found amongst peoples of North East Africa, Arizona Indians and in India. It comes in many shapes and sizes depending on its geographic/tribal origins and intended function. The most recognizable type is the returning boomerang, a kind of Throwing Stick that, when thrown correctly, travels in a curved path and returns to its point of origin. Other types of boomerang are of the non-returning sort, and indeed, some are not thrown at all but are used in hand-to-hand combat by Aboriginal people Boomerangs can be variously used as hunting weapons, percussive musical instruments, battle clubs, fire-starters, decoys for hunting waterfowl, and as recreational playthings. The smallest boomerang may be less than 10 cm from tip-to-tip, and the largest over 2 meters in length. Tribal boomerangs may be incised and/or painted with designs meaningful to its maker. Most boomerangs seen today are of the tourist or competition sort, and are almost invariably of the returning type.

History
Boomerang-like devices, including hunting sticks, have been used all over the world for hunting, religious and recreational activities. Their origin is still not fully clear. Research has shown that ancient tribes in Europe used special throwing axes. Also, in ancient Egypt a special type of stick was exclusively used by the pharaohs for hunting birds. However, the world famous "country of the boomerang" is Australia, where the Australian Aborigines have used both boomerangs and hunting sticks for many thousands of years. The name of the boomerang comes from the Indigenous Australian Turuwal tribe of Aborigines who lived south of Sydney, Australia.

Today, boomerangs are most 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 colors. Most sport boomerangs typically weigh less than 100 grams, with MTA boomerangs (boomerangs used for the maximum time aloft event) often under 25 grams.

Design
A returning boomerang is an airfoil. 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, the wings produce lift. Larger boomerangs are used in hunting, thus they drop on the ground after striking the target. Smaller ones are used in sport, and are the only boomerangs that return to the thrower. Because of its rapid spinning, a boomerang flies in a curve rather than a straight line. When thrown correctly, a boomerang returns to its starting point.

Now in more detail
Returning boomerangs consist of two or more arms or wings, connected at an angle. Each wing is shaped as an airfoil, air travels faster over one surface of an airfoil than the other, as the air is accelerated due to the curvature, thus creating lift, along what is roughly a plane which intersects the airfoil at a near right angle along the long axis of the wing.

These wings are set so that the lift created by each wing opposes the lift of the other, but at an angle such that the flight pattern is constantly shifted as the forces of lift, drag, speed, rotational inertia etc. 'attempt' to reach equilibrium, see Boomerang engineer.

This is what makes the boomerang 'return gracefully to the thrower, fluttering to a stop in his hand'... when thrown correctly. This is also what makes the boomerang 'rocket straight up into the air before plunging to its shattered doom'... when thrown incorrectly. With the exception of long-distance boomerangs, they should not be thrown sidearm or like a frisbee, but rather throw with the long axis of the wings rotating in an almost-vertical plane.

Fast Catch boomerangs usually have three symmetrical wings (in the planform view), whereas a Long Distance boomerang is most often shaped very similar to a question mark. Maximum Time Aloft boomerangs 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 maximize the boomerang's hover-time in descending from its highest point in the flight.

Basic throwing instructions
A right-handed boomerang circles towards the left, a left-handed boomerang circles towards the right. Most sport boomerangs are in the range of 2.5 to about 4 ounces. The range on most of these is between 25 - 40 yards (or meters)

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 handedness requires a throwing motion that will feel awkward to many throwers. Beginners should thus take care to get a boomerang with the right handedness.

Grasp one wing of the boomerang nearly vertically so that the other wing points forward and the flat side is away from you. The other way works also, but this way is usually easier to learn. Holding the tip by just the end between your thumb and one or two fingers, launch the boomerang forward quickly while trying more for spin than for very much force.

The boomerang should flatten out on its own and arc around, sometimes coming to rest a little in front of the thrower or behind the thrower, but ideally it should hover gently and allow the thrower to catch it as a sort of "boomerang sandwich" between the thrower's hands.

One should not throw a returning boomerang level, like a flying disc. The boomerang will turn in the direction of the top of its airfoils, so if that direction happens to be up rather than to the side it may fly high enough that the landing causes damage to the boomerang or whatever it lands on.