THE BEAUTY Of THE BOOMERANG

Image Gallery The different grain patterns on this homemade boomerang show where wood should be sanded away in order to shape the airfoil for graceful flight. This particular model measures 12 inches from tip to tip, and is made of strong, 3/8"" aircraft-grade plywood

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Issue # 70 - July/August 1981

Kent Meyers

For pure grace and beauty—as well as for a stirring example of the wonder, symmetry, and constancy of nature's laws—the delicate, balanced, and bird-like flight of a boomerang is hard to beat. Even when the forces acting upon the device are explained and understood, its dramatic soaring is—as things controlled by nature tend to be—still, in essence, a mystery.

Once thrown, a "return" boomerang travels in arising, circular flight. If the wielder is right-handed, it will fly up and around to his or her left (the circle is reversed when the thrower is a southpaw) . . . reaches its peak at a point about 45° from the line of the direction in which it was thrown . . . then begins a gradual, circling descent . . . and either glides gently to the ground or hovers for a few seconds before dropping. The commonly made comparison of its flight to that of a predatory bird is quite accurate. In fact, some primitive tribes, by throwing return boomerangs into the air while imitating a hawk's cry, are able to keep small birds on the ground and thus drive them into nets.

Generally, however, the return boomerang is used as a toy. It will typically weigh less than five ounces, and the angle of its limbs—each of which is no more than a foot long—can be as extreme as 90°. The approximately pound-and-a-half hunting versions, on the other hand, have gradual curves and overall lengths sometimes surpassing three feet. They can travel up to 250 yards in a straight line and are used by Australian aborigines for felling animals and birds.

HOW IT FLIES!

Return boomerangs operate on the principle of the airfoil. Their upper surfaces are curved, much like the top of an airplane's wing, while the undersides are flat. As one of these aerodynamic implements slices through space, the air flows faster over the greater surface area of the curved top, and (since, as the velocity of air increases, its pressure decreases) a partial vacuum is created. Therefore, the greater air pressure against the flat side pulls the boomerang up, around, and back to its starting point (the hunting boomerang is shaped to provide some lift in straight flight).

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