Concept and Initial Design

I brainstormed a mechanism to speed up the beyblade and designed one plate of the beyblade’s chassis in Fusion.

Background

In the Beyblade Burst anime series, Fafnir is a left-spinning top that is widely known for its ability to “steal spin” from its right-spinning opponents. It appears to magically increase its own angular speed with every hit and then outlast its opponent. However, in reality, this ends in more draws rather than wins. Additionally, the physical beyblade doesn’t gain a “sudden boost” of spin as depicted in the anime.

How Does it Work?

Think of two gears isolated from each other. One gear is spinning clockwise (CW) and the other isn’t spinning at all. If the two gears were put near each other to the point where the teeth interlock, then you would be able to see that the other previously stationary gear begins to spin in the other direction (counterclockwise, or CCW). In the Beyblade world, Fafnir is launched CCW with very little spin power, so it gains more spin whenever it is hit by a CW attack. The main principle here is that the two Beyblades are trying to reach the same angular speed whenever they are in contact, so if the CCW is slower than the CW one, the CW beyblade will transfer some of its spin over to the other beyblade to help reach a point of equilibrium. Unfortunately, what happens often in real life is that the two beyblades hit each other until they are spinning at the same speed, and then they both run out of spin at the same time.

Conservation of Angular Momentum

Angular momentum is defined as L = I * ω, where I represents the moment of inertia and ω represents the angular velocity. The conservation of angular momentum states that this quantity remains constant unless acted on by an external torque (ignore friction for now). This means that if the moment of inertia were to decrease, then the angular speed would have to increase in order to maintain a constant angular momentum. But how do we reduce the moment of inertia? Well, I won’t get too deep in the details, but an easy way to do so is to move the mass distribution closer to the beyblade’s center of gravity.

The Mechanism

I’ll keep four masses that are attached to neodymium magnets near the edge of the beyblade, and I’ll have a rotating wall with four pockets. The magnets on the edge will have the same polarity, and there will be another magnet (with opposite polarity) at the center of the beyblade’s energy layer that pulls the other ones in. Usually, the wall will prevent this attraction. However, if the wall is tilted such that the pockets are exposed, then the outer weights will instantly get pulled towards the center of the beyblade; hence, the moment of inertia of this system is lowered, and it will speed up to conserve angular momentum.