Why running English for multiple rails kicks?

[bbb]

If that's the case it seems like no English is better, since the path is more ideal

there is NO IDEAL PATH IN MY OPINION
i think whats most important is that you can predict accurately where the cue ball will go .
the cue ball will take certain paths with spin and those paths will vary depending on how much and what type of spin
and other paths with no spin.
the main thing is you have to learn what the cue ball will do based on the amount of spin from zero to max (inside or outside )
you can hit a million balls and learn to "see" and "feel" it
or you can learn systems which will give you a map so you do not have to re invent the wheel
yes the knock on systems is that not all tables play like a systems formula so you have to make adjustments
speaking for myself and i am a systems player
for me the systems got me kicking at a success rate way above my pool skills
with time i developed "feel" as i learned and watched what the cue ball did and how it reacted
adding to my ability to adjust to the different table conditions
i want to say again running vs no english is not one is better
the cue ball will take a different path and knowing where it will go will let you choose what path you want it to take
ie
your gps can have more than one route to get where you are going in many situations
jmho
icbw

 

[Jack Fate]

there is NO IDEAL PATH IN MY OPINION
i think whats most important is that you can predict accurately where the cue ball will go .
the cue ball will take certain paths with spin and those paths will vary depending on how much and what type of spin
and other paths with no spin.
the main thing is you have to learn what the cue ball will do based on the amount of spin from zero to max (inside or outside )
you can hit a million balls and learn to "see" and "feel" it
or you can learn systems which will give you a map so you do not have to re invent the wheel
yes the knock on systems is that not all tables play like a systems formula so you have to make adjustments
speaking for myself and i am a systems player
for me the systems got me kicking at a success rate way above my pool skills
with time i developed "feel" as i learned and watched what the cue ball did and how it reacted
adding to my ability to adjust to the different table conditions
i want to say again running vs no english is not one is better
the cue ball will take a different path and knowing where it will go will let you choose what path you want it to take
ie
your gps can have more than one route to get where you are going in many situations
jmho
icbw

I’ve been relearning the systems I have learned over 20 years ago. Add YouTube and in the last year I’ve been learning more systems and getting some good results.( some I abandon )The thing on some systems is English used & the zone in which it works. Some don’t do a complete lesson, omitting these critical items. Some really do a great job of covering the details . I have white boards on the wall at home with newer systems that I have yet to memorize.
Learning something new helps keep things interesting.
Old dogs can learn new tricks!

 

[BilliardsAbout]

Dr. Cue's outstanding web instruction on kicking/banking on YouTube includes english amounts for varied multi-rail shots.

 

[maha]

it is much easier to hit the center of the cue ball and learn that effect on your rail shots.

when you use english you can be a little off and not know it as its harder to judge 2/5 off center or some such.

learn without english first then go from there.

 

[nataddrho]

The answer to your question is "conservation of momentum". Newtons laws, basic physics.

In a perfectly elastic system, if the spin and speed of a ball entering a rail is similar to that of its exit, then the entry angle will equal the exit angle (mirror).

Total momentum of a Newtonian object (which includes both translational and rotational components) before an elastic collision must equal the total momentum of the object after the collision. Since the mass of the collision components do not change, only the vector magnitudes and angles are modified.

In the real world system, the collsion is inelastic (there is a small energy loss between the ball/rail and the ball/cloth), so there are slight variances from a perfect system, but the dominant phenomena that causes a change in exit angle is the law of conservation of momentum. The cloth is designed to be slippery to reduce friction, and the rails are rubber and are designed to be elastic. Pool is designed to be as elastic as possible within playability. Pocketless billiards even more so.

One will notice that if a ball hits a rail and picks up spin from the collision but the speed is about the same or less, then the exit angle is wider. This is because the rail friction created torque on the ball, and since the rail does not actively add energy to the collision, the energy for the extra spin must come from the translational component. The only way to maintain the same momentum is if the rebound angle increases.

Different angles in incidence will cause different amounts of energy transfer between components, and thus different exit angle modifications. This is why trying to keep the entry and exit spin of the ball the same will minimize the exit angle modification away from a "mirror".

Running English is a term used to do this very thing.

 

[bbb]

The answer to your question is "conservation of momentum". Newtons laws, basic physics.

In a perfectly elastic system, if the spin and speed of a ball entering a rail is similar to that of its exit, then the entry angle will equal the exit angle (mirror).

Total momentum of a Newtonian object (which includes both translational and rotational components) before an elastic collision must equal the total momentum of the object after the collision. Since the mass of the collision components do not change, only the vector magnitudes and angles are modified.

In the real world system, the collsion is inelastic (there is a small energy loss between the ball/rail and the ball/cloth), so there are slight variances from a perfect system, but the dominant phenomena that causes a change in exit angle is the law of conservation of momentum. The cloth is designed to be slippery to reduce friction, and the rails are rubber and are designed to be elastic. Pool is designed to be as elastic as possible within playability. Pocketless billiards even more so.

One will notice that if a ball hits a rail and picks up spin from the collision but the speed is about the same or less, then the exit angle is wider. This is because the rail friction created torque on the ball, and since the rail does not actively add energy to the collision, the energy for the extra spin must come from the translational component. The only way to maintain the same momentum is if the rebound angle increases.

Different angles in incidence will cause different amounts of energy transfer between components, and thus different exit angle modifications. This is why trying to keep the entry and exit spin of the ball the same will minimize the exit angle modification away from a "mirror".

Running English is a term used to do this very thing.

great post
wish i understood everything you said.....

 

[straightline]

Wutty said.

 

[Pubo]

The answer to your question is "conservation of momentum". Newtons laws, basic physics.

In a perfectly elastic system, if the spin and speed of a ball entering a rail is similar to that of its exit, then the entry angle will equal the exit angle (mirror).

Total momentum of a Newtonian object (which includes both translational and rotational components) before an elastic collision must equal the total momentum of the object after the collision. Since the mass of the collision components do not change, only the vector magnitudes and angles are modified.

In the real world system, the collsion is inelastic (there is a small energy loss between the ball/rail and the ball/cloth), so there are slight variances from a perfect system, but the dominant phenomena that causes a change in exit angle is the law of conservation of momentum. The cloth is designed to be slippery to reduce friction, and the rails are rubber and are designed to be elastic. Pool is designed to be as elastic as possible within playability. Pocketless billiards even more so.

One will notice that if a ball hits a rail and picks up spin from the collision but the speed is about the same or less, then the exit angle is wider. This is because the rail friction created torque on the ball, and since the rail does not actively add energy to the collision, the energy for the extra spin must come from the translational component. The only way to maintain the same momentum is if the rebound angle increases.

Different angles in incidence will cause different amounts of energy transfer between components, and thus different exit angle modifications. This is why trying to keep the entry and exit spin of the ball the same will minimize the exit angle modification away from a "mirror".

Running English is a term used to do this very thing.

Thank you so much for the awesome discussion on physics! I have a couple questions.
1.

One will notice that if a ball hits a rail and picks up spin from the collision but the speed is about the same or less, then the exit angle is wider.

Do you mean that the exit line is closer to the perpendicular to the rail? Since the rotational energy of CB can only come from translational energy, and it is the velocity component of CB parallel to the rail that causes the rubbing of CB and the rail, the parallel velocity component must decrease, and the CB will exit the rail along the line closer to the perpendicular to the rail compared to its entry line. So in principle, every kick banks short because of this.

2. The use of (appropriate amount of) running spin is to make sure that there is no relative motion between CB contact point and the rail so no torque is applied, and the CB path will closely follow the mirror reflection.


Thank you in advance!

 

[bbb]

Thank you so much for the awesome discussion on physics! I have a couple questions.
1.

Do you mean that the exit line is closer to the perpendicular to the rail? Since the rotational energy of CB can only come from translational energy, and it is the velocity component of CB parallel to the rail that causes the rubbing of CB and the rail, the parallel velocity component must decrease, and the CB will exit the rail along the line closer to the perpendicular to the rail compared to its entry line. So in principle, every kick banks short because of this.

2. The use of (appropriate amount of) running spin is to make sure that there is no relative motion between CB contact point and the rail so no torque is applied, and the CB path will closely follow the mirror reflection.


Thank you in advance!

i am happy you can speak his language....

 

[nataddrho]

It is not true that every kick banks short, but most do.

The exit line (angle) depends on the spin (and to some degree speed due to further complexities that deviate from a simple model). The direction of spin has a large impact on the exit angle. We use running English to try to match the exit spin to the entry spin, but anything else has interesting results.

Here is a paper where the author studies the science of rail-ball interactions. It is so complicated that there is no closed form solution and numerical methods are used to solve the partial differential equations.

The plots at the end are very informative. The only rebound angles that are less than the incident angle (banks long according to the authors nomenclature) are ones with sidespin k=1 and k=2. Otherwise yes, the other shot types bank short.

 

[Patrick Johnson]

It is not true that every kick banks short, but most do.

A rolling CB usually makes the rebound angle go longer (wider) than the incoming angle. There's even a commonly known method to adjust aim for it: instead of aiming at the place where the CB contacts the rail (the "equal angle" point), aim at the rail behind it (i.e., a sharper kick angle) so the rolling-CB masse will widen the rebound back to the equal angle.

pj
chgo

 

[Pubo]

It is not true that every kick banks short, but most do.

The exit line (angle) depends on the spin (and to some degree speed due to further complexities that deviate from a simple model). The direction of spin has a large impact on the exit angle. We use running English to try to match the exit spin to the entry spin, but anything else has interesting results.

Here is a paper where the author studies the science of rail-ball interactions. It is so complicated that there is no closed form solution and numerical methods are used to solve the partial differential equations.

The plots at the end are very informative. The only rebound angles that are less than the incident angle (banks long according to the authors nomenclature) are ones with sidespin k=1 and k=2. Otherwise yes, the other shot types bank short.

Thanks for the paper! I'll read it

 

[Pubo]

A rolling CB usually makes the rebound angle go longer (wider) than the incoming angle. There's even a commonly known method to adjust aim for it: instead of aiming at the place where the CB contacts the rail (the "equal angle" point), aim at the rail behind it (i.e., a sharper kick angle) so the rolling-CB masse will widen the rebound back to the equal angle.

pj
chgo

View attachment 690519

But this is not the rebound angle (measured immediately after rebound) right? It's the total effect of CB curving because of top spin plus the rebound angle.

 

[nataddrho]

A rolling CB usually makes the rebound angle go longer (wider) than the incoming angle. There's even a commonly known method to adjust aim for it: instead of aiming at the place where the CB contacts the rail (the "equal angle" point), aim at the rail behind it (i.e., a sharper kick angle) so the rolling-CB masse will widen the rebound back to the equal angle.

pj
chgo

View attachment 690519

You need to be careful about what specifically you are talking about. The ball-rail physics causes the ball to rebound with a shorter angle, however, if using a naturally rolling ball, then the residual top spin from after the collision changes the cue ball path. This is illustrated in your diagrams by the tiny little bend of the white line right after the collision.

What happens is that since the shelf of the cushion is slightly higher than the center of the cue ball (about 0.1 to 0.15R), a downward force is applied to the cueball during the collision which makes the cue ball hop into the air. Not by very much but it is there. There is no cloth friction during this time. When the cue ball lands the top spin grabs the cloth and bends the path long.

This affect is used often in 3-C billiards to make very long angles, and speed is used to modify the time until the cue ball grabs and bends. All very interesting and fun.

 

[Patrick Johnson]

But this is not the rebound angle (measured immediately after rebound) right?

It's the final rolling path after masse (usually happens within a foot or so of rebounding) - which, of course, determines where the CB finally goes.

pj
chgo

 

[boogieman]

Genuine question: When you kick by feel, do you use running spin? If so, why is using running spin better than plain ball?

Personally I kick with high ball and adjust angle by speed. You can get deadly accurate with just high ball, spin complicates things. I'll use running english for 3 rail kicks but that's about it. If I'm using english on a kick it is more to control the CB after it contacts the OB.

Of course there are exceptions but I usually adjust for them by feel or rote memory.

 

[bbb]

It is not true that every kick banks short, but most do.

The exit line (angle) depends on the spin (and to some degree speed due to further complexities that deviate from a simple model). The direction of spin has a large impact on the exit angle. We use running English to try to match the exit spin to the entry spin, but anything else has interesting results.

Here is a paper where the author studies the science of rail-ball interactions. It is so complicated that there is no closed form solution and numerical methods are used to solve the partial differential equations.

The plots at the end are very informative. The only rebound angles that are less than the incident angle (banks long according to the authors nomenclature) are ones with sidespin k=1 and k=2. Otherwise yes, the other shot types bank short.

i do not understand the paper you linked but i am sure you do
below is a screen shot of the conclusion
could you translate what it says in to pool player english?
thanks
.....................
............................

 

[bbb]

But this is not the rebound angle (measured immediately after rebound) right? It's the total effect of CB curving because of top spin plus the rebound angle.

arent you most concerned with where the cue ball goes?
instead of the few inches into and out of the rail?

 

[Pubo]

arent you most concerned with where the cue ball goes?
instead of the few inches into and out of the rail?

I'm just curious about the physics that go into the common practice of putting running English on multi-rail kicks. I don't mean to dismiss PJ's diagrams and explanations. I love them all along! I just want to ask questions and get real knowledge both theoretically and practically.

 

[bbb]

I'm just curious about the physics that go into the common practice of putting running English on multi-rail kicks. I don't mean to dismiss PJ's diagrams and explanations. I love them all along! I just want to ask questions and get real knowledge both theoretically and practically.

the physics of pocket billiards by wayland marlow might be a great book for you

Wayland C Marlow - AbeBooks

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