How Do Boomerangs Work?
The science of the boomerang’s return flight
Although stone age civilizations invented the boomerang, the aerodynamics and physics of its flight are still not completely understood by today’s experts.
The really short version:
Boomerangs return as a result of the principles of aerodynamic lift and gyroscopic precession.
The short version:
Understanding why a boomerang comes back is as easy as understanding why an airplane wing generates lift and why you can steer your bicycle with no hands. The wings of a boomerang are airfoils, like an airplane’s wing. When moving through the air, airfoils generate lift because of their shape, which causes air to move faster over top surface than the bottom surface. Faster moving air over the top surface causes relatively higher pressure on the bottom surface, causing the wing to “lift” up.
Boomerangs are thrown vertically, and spinning, like a knife. As the boomerang moves forward through the air, it is also spinning, and more lift is generated at the top of the spin than at the bottom. Because the wing at the top is moving forward and spinning forward, whereas the wing at the bottom is moving forward, but spinning backward the wing at the top is actually moving faster through the air. Since the wing at the top position is moving faster through the air, more lift is generated at the top position. If the boomerang were not spinning, more lift at the top would cause the boomerang to fall over, like a three year-old on a bicycle with no training wheels. But it doesn’t. It turns gently, like a cocky 12 year-old steering his bike with his “no-hands” maneuver. Why? Because of gyroscopic precession. Gyroscopic precession states that any force applied to a spinning object will take effect 90 degrees forward in the direction of the spin from the where the force was applied. So, you want to make your bicycle turn left. But instead of pushing the wheel to the left (from the front), you push it from the top, but the effect takes place on the front. The same thing happens with a boomerang. The maximum lift takes place on the top of the spin, but the lift force takes effect on the front, causing the boomerang to turn and, ultimately, to return.
Learn more about the science of boomerang flight here!
How to throw a boomerang: