Boomerang as Vector Rotation Example

The returning trajectory of a boomerang involves the aerodynamic lift of its airfoil shape plus the gyroscopic precession associated with its rapid spin. The precession redirects the airfoil so that it "flys" around the returning path.

The three diagrams above address the nature of the boomerang's flight. Click on one of the diagrams for further details about the boomerang. 		Index

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Boomerang

A boomerang is an example of gyroscopic precession. The popular variety at left is thrown by grasping it at the bottom and throwing it so that it rotates about an axis perpendicular to the plane shown. This plane is tilted enough from the vertical enough to get enough lift to keep the boomerang airborne. The cross-section at each end is shaped as an airfoil with its leading edge pointed so that it is facing forward when that end is at the top. The airfoil causes it to "fly" in the direction thrown, but the higher aerodynamic lift on the top end creates a torque which causes the angular momentum to precess, gradually changing the heading of the airfoil and moving it in the curved path.
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Boomerang

A boomerang is an example of gyroscopic precession. The boomerang throw gives it angular momentum. This angular momentum is caused to precess by the fact that the top edge is traveling faster with respect to the air and gets more lift. This produces a torque on the spinning boomerang which continually rotates it's axis of spin, changing the heading of the airfoil so that it follows the curved path.
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Boomerang

A boomerang is an example of gyroscopic precession. The throw of the boomerang gives it an angular velocity perpendicular to its path as shown. The cross-section of the boomerang is an airfoil which gives it more lift on the top, leading edge than on the bottom. This gives it a torque in the sense shown, which always acts to precess the boomerang counterclockwise as seen from above. Since it will tend to "fly" in the direction of the airfoil, the precession causes it to fly in a curved path, circling back toward the thrower.

My experience with throwing a large boomerang was that it came back to me at such high speed that I was glad I had a tree to get behind for the return!

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Boomerang Structure

The structure of a boomerang is such that each end forms an airfoil heading into the wind when it is at the top of its motion. Therefore the sideways "lift" force is always greater on the top of the spinning structure.

A boomerang is an example of gyroscopic precession. The throw of the boomerang gives it an angular velocity perpendicular to its path. The cross-section of the boomerang is an airfoil which gives it more lift on the top, leading edge than on the bottom. This gives it a torque , which always acts to precess the boomerang counterclockwise as seen from above. Since it will tend to "fly" in the direction of the airfoil, the precession causes it to fly in a curved path, circling back toward the thrower. 		Index
 
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