Physical Science - Other

# Why Boomerangs come Back sometimes

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"Why Boomerangs come Back sometimes"
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Understanding how boomerangs fly has been a quest for scientists for thousands of years, despite the fact that the boomerang has been in use for over 10,000 years. Recent aerodynamic discoveries have made understanding the principles behind its flight easier to grasp, as well as the application of gyroscopic forces. Thrown correctly a boomerang can travel quite quickly, accurately and, due to the principles of its design, can return on a direct path back to the person who threw it. Understanding why the boomerang is capable of doing this requires a quick look at the principles of its flight, including the design of its two airfoils.

In order to achieve flight, sufficient lift must be created to take the object into the air. The boomerang essentially consists of two airfoils, or wings, that are melded together to form a "v" shape. When the boomerang is thrown, the leading edges of the wings are facing the direction of the spin and greater lift can be achieved. Due to its rotation, however, the wing that is in the top position is moving faster than the one in the lower position.

This has to do with discoveries pointing out that wind travels faster over the top section of an airfoil rather than the bottom. Due to the twin airfoil design and the direction of the rotation, this increased airspeed in the top position causes a directional change to slowly occur during flight. The change is gradual as the wing in the bottom position adjusts to the difference in speed. This occurs in a time frame relative to when certain gyroscopic forces also begin to act upon the flight of the boomerang.

Acting in much the same way as a helicopter rotor that isn’t attached to anything, the boomerang maintains its flight by rotating and achieving lift. Due to the principle of gyroscopic precession however, the boomerang is able to turn around in mid flight and return to the person who threw it. Gyroscopic precession maintains that any force acting upon a rotating object will be manifested 90 degrees forward in the direction of the object's spin. In the case of the boomerang with its specially designed twin-airfoil construction, when thrown with the correct trajectory and force this causes a change of direction in mid-flight. In addition to the principles of lift that are applied to the rotation of the boomerang's airfoils, gyroscopic precession enables the boomerang to turn on its own trajectory.

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