BubbaRay
11-10-2007, 08:05 PM
Although at first sight a bowling ball appears to be a simple product, the dynamics of a ball as it travels down the lane are in fact quite complex. The ball undergoes gyroscopic influences due to the core design of the ball, and it interacts with an oiled lane surface whose friction can vary from day to day—indeed, from throw to throw—in accordance with the amount of oil on the lane, and as oil gradually builds up on the ball. Moreover, when the ball finally reaches the pins, an enormous contact problem is created, with the ball contacting the pins, and the pins then contacting other pins, the lane, and the gutters.
Serious bowlers are buying additional bowling balls appropriate for the wide variety of lane conditions encountered as they travel from one alley to another.
In response to changing market conditions, the design of bowling balls has undergone a dramatic series of changes over the past 20 years. For many years, typical bowling balls were uniform, with a spherical core located in the center of the ball. Because the ball had a uniform inertia, it made no difference (from a rotational-dynamics standpoint) where the ball was drilled.
Things started to change in the early 1980s with the introduction of nonspherical symmetric cores. Such cores are shaped in patterns resembling a light bulb, for instance, or a pineapple. Accordingly, this type of ball has two principal inertias—one along the axis of the core and another perpendicular to it. If the axis of the core coincides with the initial rotation of the ball, it will behave in a manner similar to earlier balls. The same applies if the initial rotation is in the plane is perpendicular to the core axis. However, if the initial rotation of the ball is about any other axis, interesting things start to happen.
First, the rotation axis processes about the core axis—that is, the motion of rotation of the rotation axis describes a cone about the core axis. With each rotation of the ball, a different set of points, or "track," on the ball touches the lane. This change in lane contact, called track flare, produces a bow-tie-like pattern of circles across the ball.
Because of the oil on the lane, track flare becomes very important to ball performance. With conventional spherical cores, the ball stays on one track, which quickly becomes covered with oil. Presenting a dry section of the ball to the lane on every revolution maintains the friction between the ball and the lane. This increased friction, in turn, increases the ball's hook, thereby creating a bigger "pocket."
Increasing the differential between the least-moment-of-inertia axis and the axis of rotation as well as positioning the rotation axis generally lead to greater track flare. This in turn increases the amount of friction between the ball and the lane, which allows for a greater hook. The larger hook raises the angle at which the ball hits the pins, increasing the probability of a strike.
another major advance was introducing the asymmetric core. This was important because conventional nonspherical cores only allow a single degree of freedom in tuning the performance of the ball.
Since today's bowlers want more than just a ball with a lot of hook, tuning ball performance is much more complicated than simply maximizing the hook angle. The asymmetric cores used in balls typically are shaped like pills or ellipsoids. The performance of a ball with a conventional symmetric core can be varied only by changing the axis of rotation of the ball in relation to the core's axis, while the asymmetric core has three distinct principal inertial axes in relation to which the rotation axis can be positioned. An asymmetric core therefore provides the ball driller with a wide range of track-flare potential, which can be used to tailor the ball's performance to a given bowler.
Serious bowlers are buying additional bowling balls appropriate for the wide variety of lane conditions encountered as they travel from one alley to another.
In response to changing market conditions, the design of bowling balls has undergone a dramatic series of changes over the past 20 years. For many years, typical bowling balls were uniform, with a spherical core located in the center of the ball. Because the ball had a uniform inertia, it made no difference (from a rotational-dynamics standpoint) where the ball was drilled.
Things started to change in the early 1980s with the introduction of nonspherical symmetric cores. Such cores are shaped in patterns resembling a light bulb, for instance, or a pineapple. Accordingly, this type of ball has two principal inertias—one along the axis of the core and another perpendicular to it. If the axis of the core coincides with the initial rotation of the ball, it will behave in a manner similar to earlier balls. The same applies if the initial rotation is in the plane is perpendicular to the core axis. However, if the initial rotation of the ball is about any other axis, interesting things start to happen.
First, the rotation axis processes about the core axis—that is, the motion of rotation of the rotation axis describes a cone about the core axis. With each rotation of the ball, a different set of points, or "track," on the ball touches the lane. This change in lane contact, called track flare, produces a bow-tie-like pattern of circles across the ball.
Because of the oil on the lane, track flare becomes very important to ball performance. With conventional spherical cores, the ball stays on one track, which quickly becomes covered with oil. Presenting a dry section of the ball to the lane on every revolution maintains the friction between the ball and the lane. This increased friction, in turn, increases the ball's hook, thereby creating a bigger "pocket."
Increasing the differential between the least-moment-of-inertia axis and the axis of rotation as well as positioning the rotation axis generally lead to greater track flare. This in turn increases the amount of friction between the ball and the lane, which allows for a greater hook. The larger hook raises the angle at which the ball hits the pins, increasing the probability of a strike.
another major advance was introducing the asymmetric core. This was important because conventional nonspherical cores only allow a single degree of freedom in tuning the performance of the ball.
Since today's bowlers want more than just a ball with a lot of hook, tuning ball performance is much more complicated than simply maximizing the hook angle. The asymmetric cores used in balls typically are shaped like pills or ellipsoids. The performance of a ball with a conventional symmetric core can be varied only by changing the axis of rotation of the ball in relation to the core's axis, while the asymmetric core has three distinct principal inertial axes in relation to which the rotation axis can be positioned. An asymmetric core therefore provides the ball driller with a wide range of track-flare potential, which can be used to tailor the ball's performance to a given bowler.