cgeorg wrote:Great response by MathIsTruth. It seems that you're saying the effect of MB is that it changes the migratory path of the spin axis, making it a different shape of ellipse.
Is the theory that as the ball approaches the major axis of the ellipse (which would be on the pin-to-spin line), that the axis migration speeds up, and once it crosses this line towards the minor axis, it slows back down again? This would result in maximum track flare (and friction) at the pin-to-spin line. A greater intermediate diff would create a more elongated ellipse, which would increase the magnitude of change in axis migration speed. It would also presumably cause a visible difference in the spacing between flare rings. Or is "what actually happens at the pin-to-spin line?" the remaining unknown?
The migratory path of the spin axis for ALL bowling balls is determined by the RG profile of the ball. The RG profile is a consequence of the Low, Intermediate and High RG values along with the Total and Intermediate Differentials of the ball. The spin axis will migrate and maintain an RG value which is equal to the RG value of the original PAP. In EVERY bowling ball used, the migratory path is elliptical in nature. Symmetrically cored bowling balls also exhibit this behavior but due to their low Intermediate Differential, their path will be less elliptical. You can see from the MoRich Nsane axis migration picture in post #50, that the spin axis migration is in fact an elliptical path which is centered about the PSA.
We believe that the precessional rate of the migrating axis may increase slightly while the spin axis is approaching the Pin to Spin line but will accelerate AFTER the spin axis crosses the Pin to Spin Line. We also believe that the acceleration of the migrating spin axis will be greater in bowling balls with higher Diff Ratios than lower Diff Ratios due to the slope of the RG contours.
I have included a picture below which will compare the migratory path of the spin axis for four bowling balls with the same drilling layout of 10x4.25”x20 with a P4 balance hole. The axis migration can be seen in blue for the MoRich Nsane, in purple for the MoRich Frenzy, in orange for the MoRich Mojave and in green for a symmetrical cored ball.
NOTE: I made an error in post #25 that I would like to correct, the Pin to Spin line falls on the minor axis, not the major axis. This can be seen after close examination in the MoRich Nsane picture above. I have corrected this mistake in post #25 for future reference, my apologies. Thank you for this very insightful question!!
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