Assymetrical core dynamics

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russelldean
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Assymetrical core dynamics

Post by russelldean »

Studying the wiki.
What are the relationships of pin distance from pap placements, that dictate ball rolls different then that in symmetrical balls. Do longer pin placements in assymetricals create more forward roll, because the high rg become more dominant when pin is close to track? Why does shorter pin placement in assymetrical creat more skid flip? Takes longer to transition due to lower flare? Does the intermediate rg factor in to the equation?
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Re: Assymetrical core dynamics

Post by JohnP »

Have you read Mo's article on Dual Angle Layouts (on the wiki and the MoRich website)? Most of that information is in there in the "Applying Dual Angle Layouts" (or something similar) section near the end. -- JohnP
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Re: Assymetrical core dynamics

Post by russelldean »

Yes John,
I understand the reaction, but did not see the physics behind it.
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Re: Assymetrical core dynamics

Post by JohnP »

OK, I see - you want the "why" not the "what". That's for Mo or Math is Truth to answer. Remember, they don't read everything on this board, if you want to be sure they see it move it to one of the "Mo and Friends" forums. -- JohnP
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Re: Assymetrical core dynamics

Post by russelldean »

Thanks John..
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Re: Assymetrical core dynamics

Post by The Kid »

Recently, I asked a very similar question here: viewtopic.php?f=15&t=2569.

More recently than that, I asked a follow up question (with an answer) here: viewtopic.php?f=6&t=2834

The condensed answer is that an asymmetrical ball only has one stable axis, while a symmetrical has two.

Because the PAP on an asymmetrical ball is only stable if the Pin is 0" away (Pin on PAP), the flare only increases as the Pin-to-PAP distance grows from 3/4" to 6 1/4" (between 6 1/4" and 6 3/4", somethings funky happens supposedly).

For a symmetrical ball, on the other hand, the PAP is stable at 0" from the Pin and 6 3/4" from the PAP (two stable axes).


Because of this (and you are right about this), true skid-flip on an asymmetrical bowling ball requires a shorter Pin-to PAP so that the ball has less flare.
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Re: Assymetrical core dynamics

Post by russelldean »

Kid,
That is what I am looking for...thanks. So i assume the main factor is the Intermediate diff (mass bias strength) and its location. I did drill one assymetrical ball with the pin and the mb in the track. I assume this ball had a stable pap for the most part.
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Re: Assymetrical core dynamics

Post by The Kid »

With the Pin in the track, it is likely that the Pin-to-PAP was 5-6 1/2". That is unstable for an asymmetrical ball. The ball, however, would've had an extremely large angle sum with the PSA (mass bias) in the track also.

I bet the reaction was extremely calm, but the Pin placement is actually strong (not stable).
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Re: Assymetrical core dynamics

Post by russelldean »

The ball did not flare much at all. Wanted something with low flare that i could use with a strong cover. This ball bailed me out on some wicked wet/dry.
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Re: Assymetrical core dynamics

Post by Mo Pinel »

russelldean wrote:Studying the wiki.
What are the relationships of pin distance from pap placements, that dictate ball rolls different then that in symmetrical balls. Do longer pin placements in assymetricals create more forward roll, because the high rg become more dominant when pin is close to track? Why does shorter pin placement in assymetrical creat more skid flip? Takes longer to transition due to lower flare? Does the intermediate rg factor in to the equation?

Intermediate diff. and diff. ratio determine whether there are RG profiles around the low RG axis only, or both the low and high RG axis. If the RG contours are only around the low RG axis, it's symmetrical. If they're around both axis, it's asymmetrical. YOURS, STEVIE!!!!!
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Re: Assymetrical core dynamics

Post by The Kid »

And I believe Steve said that if the RG of the initial PAP (which is the same as the other PAPs as well) was greater than the intermediate RG, the PAP would follow a contour around the High RG Axis. And if the RG of the initial PAP was less than the intermediate RG, then the PAP would follow a contour around the Low RG Axis.

Is that remembering correctly, or am I off base?
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Re: Assymetrical core dynamics

Post by russelldean »

Mo Pinel wrote:
Intermediate diff. and diff. ratio determine whether there are RG profiles around the low RG axis only, or both the low and high RG axis. If the RG contours are only around the low RG axis, it's symmetrical. If they're around both axis, it's asymmetrical. YOURS, STEVIE!!!!!
Great Mo,
Starting to get a visual
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Re: Assymetrical core dynamics

Post by MathIsTruth »

The Kid wrote:And I believe Steve said that if the RG of the initial PAP (which is the same as the other PAPs as well) was greater than the intermediate RG, the PAP would follow a contour around the High RG Axis. And if the RG of the initial PAP was less than the intermediate RG, then the PAP would follow a contour around the Low RG Axis.

Is that remembering correctly, or am I off base?
That is absolutely correct. The RG of the PAP is the most important RG value to be considered in the complete ball system. The RG of the PAP and the RG values of the true principal axes will determine the migration of the spin axis.
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Re: Assymetrical core dynamics

Post by russelldean »

MathIsTruth wrote: That is absolutely correct. The RG of the PAP is the most important RG value to be considered in the complete ball system. The RG of the PAP and the RG values of the true principal axes will determine the migration of the spin axis.
Would this explain why a pin placed to close to the ball track or pap, would cause different migration of the spin axis?
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Re: Assymetrical core dynamics

Post by MathIsTruth »

russelldean wrote: Would this explain why a pin placed to close to the ball track or pap, would cause different migration of the spin axis?
Yes, the migration of the spin axis is only dependent upon the location of the original PAP and the RG values of the principal axes. The migration path is determined before you even roll the ball.
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Re: Assymetrical core dynamics

Post by MathIsTruth »

These questions remind me of an old but really informative thread so in case you are newer and haven't read from the beginning, here is another thread that will help.

viewtopic.php?f=13&t=69" onclick="window.open(this.href);return false;
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Re: Assymetrical core dynamics

Post by russelldean »

Great...thank you.....
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Re: Assymetrical core dynamics

Post by The Kid »

This is a picture from a Nick Siefers study on Core Dynamics. This is a ball with the top line of x's marking the PAP contour before the weight hole. The weight hole is then placed on the initial PAP, raising it's RG. The lower line of x's marks the new RG contour (this line is closer to the High RG Axis).

Image

The whole article is here.
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Re: Assymetrical core dynamics

Post by russelldean »

With the rg going up, and pap countour going downward, would a p2 hole cause the pap contour to remian the same, and a p3/p4 hole cause the pap contour to swing upward as the rg goes down? Also if the pap contour line goes upward, can one assume the bowtie moves upward, giving one the option to fine tune a high track bowler who may track close to fingers( as long as statics could be kept in check)?
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Re: Assymetrical core dynamics

Post by cvette04 »

The Kid

I would be interested in the complete article. However I could not get to it using the link provided. Please check the link.
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