text: A returning boomerang is a propeller. 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 use in sport, and are the only boomerangs that return to the thrower. No one would think a spinning object flies a straight line, neither does the boomerang, it flies a turn or to be clearly: It flies on a circle. So it naturally returns to its starting point unless all spin is eaten up. Now in more detail:\n\nReturning 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 it follows the longer path, 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.\n\nThese 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.\n\nThis is what makes the boomerang 'return gracefully to the hurler, 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 almost vertically.\n\nFast 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.\n\nProminent boomerang designer/builders include Bob Burwell and Tony Butz from Australia, Rusty Harding from the USA, Jerri Leu from Brazil and others.\n\nFollow the link for more information.\n\nhttp://en.wikipedia.org/wiki/Boomerang#Design