Why running English for multiple rails kicks?

boogieman said:
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.
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I agree with this. For 1 rail kicks I use top and have learned that the ball comes up off the rail short, but it is predictable enough to hit the right side of the OB. 2+ rails I use center-ball spin and make sure the ball is sliding when it hits the rail, but tip position needs to be accurate.

An unintentional combination of top and side spin leads to poor results.
 
bbb said:
arent you most concerned with where the cue ball goes?
instead of the few inches into and out of the rail?
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Understanding and separating the different physical parts helps us understand what is happening.

For example, if balls bend long off of the rails we know not to blame the rail rubber or cue ball weight, compared to say the cloth dirtyness or humidity that day.

Pool players tend to complain without investigating.

Or even worse, disclaim themselves with the excuse that they haven't played much in a while LOL
 
nataddrho said:
I agree with this. For 1 rail kicks I use top and have learned that the ball comes up off the rail short, but it is predictable enough to hit the right side of the OB. 2+ rails I use center-ball spin and make sure the ball is sliding when it hits the rail, but tip position needs to be accurate.

An unintentional combination of top and side spin leads to poor results.
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Will a sliding CB into 1st cushion give better result than just use top+running english? Because after 2nd rail the CB will pick up running on it's own
 
nataddrho said:
I agree with this. For 1 rail kicks I use top and have learned that the ball comes up off the rail short, but it is predictable enough to hit the right side of the OB. 2+ rails I use center-ball spin and make sure the ball is sliding when it hits the rail, but tip position needs to be accurate.

An unintentional combination of top and side spin leads to poor results.
Click to expand...
just so i am clear
when you hit "center-ball " spin the cue ball is spinning arond its horizontal axis
and at first slides until the friction of the cloth gets it rolling also
correct?
so if you are several diamonds from a rail
dont you have to hit it pretty hard to have it sliding on contact with the rail?
so how do you kick softly?
 
nataddrho said:
Understanding and separating the different physical parts helps us understand what is happening.

For example, if balls bend long off of the rails we know not to blame the rail rubber or cue ball weight, compared to say the cloth dirtyness or humidity that day.

Pool players tend to complain without investigating.

Or even worse, disclaim themselves with the excuse that they haven't played much in a while LOL
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thanks for responding.
i am all for knowledge but for me there comes a point where all i need to know is the bottom line and not get buried in the details
the equations in that link go way beyond my desire for understanding. even though i took physics and calculus in college
i am looking for the "monarch notes" and maybe alittle more depth.
its great there are people like yourself ,Pubo and bob jewett among many who can understand it at that depth
and people like dr dave ,wayland marlow, the author of your link and many more who can present the data in that detailed of a way
(y)
 
Pubo said:
Will a sliding CB into 1st cushion give better result than just use top+running english?
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For general reference:

A sliding CB (no follow/draw) with no sidespin rebounds a little shorter than the equal angle (because of rail friction).
A sliding CB (no follow/draw) with "gearing" sidespin (no rail friction) rebounds at the equal angle.
A rolling CB (no side spin) rebounds a little longer than the equal angle (with masse).

pj
chgo
 
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Most pool shots are played to the pocket and position. A 2+ railer is like shooting a basketball into a hoop. Many paths and many arcs will allow the ball to hit the target.

In pool 2+ railer is more consistent when shot a specific way because it takes a while to release the energy.

A pool player interpretation would be
you have more position control after the CB travels a great distance (+2 rails) due to extreme follow. Extreme follow
in other circumstances means less
control for shorter length shots.

This thought process is useful for players that prefer to avoid a jump safety and favor a carom safety.
 
analysis paralysis is here.

the angle of incidence does not equal the angle of reflection due to many variables.
but its close, so start with it for the look and then adjust accordingly.
that is why center ball is best to learn. then adjust using various speeds, english etc, until you find what works for you in each situation.
every table is different.
 
nataddrho said:
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.
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I have not read the whole thing but in figure 8 they seem to be saying that the rebound speed is nearly equal to the speed into the rail for a shot straight into the rail. This is off by a factor of two for what has been observed on real tables. Either I don't understand the plot or their analysis is completely broken. This loss factor was recently discussed and is the reason you can't get 10 lengths up and down the table.
 
Pubo said:
Will a sliding CB into 1st cushion give better result than just use top+running english? Because after 2nd rail the CB will pick up running on it's own
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I find it more difficult to use sliding for soft shots, you need to time the slide. It’s good to know the affects of both types.
 
bbb said:
just so i am clear
when you hit "center-ball " spin the cue ball is spinning arond its horizontal axis
and at first slides until the friction of the cloth gets it rolling also
correct?
so if you are several diamonds from a rail
dont you have to hit it pretty hard to have it sliding on contact with the rail?
so how do you kick softly?
Click to expand...
For soft shots you should use rolling ball into the rail because timing the slide is more difficult.
 
Bob Jewett said:
I have not read the whole thing but in figure 8 they seem to be saying that the rebound speed is nearly equal to the speed into the rail for a shot straight into the rail. This is off by a factor of two for what has been observed on real tables. Either I don't understand the plot or their analysis is completely broken. This loss factor was recently discussed and is the reason you can't get 10 lengths up and down the table.
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I am not sure you meant to say what you did. A factor of two would mean the coefficient of restitution would be 0.5 or less, and the ball would rebound with half the speed? That doesn’t seem right.

From his conclusion section, the author states:
Combining some of the authors’ previous experi- mental results with the numerical solutions, the coef- ficient of restitution for the ball–cushion collision is determined as 0.98. In addition, the value for the sliding coefficient of friction is found to be 0.14.

The reason you can’t get 10 rail banks is due much more to the cloth friction than the cushion bounce. Imagine a table surface made of ice, how many rails do you think you could contact the ?
 
Bob Jewett said:
I have not read the whole thing but in figure 8 they seem to be saying that the rebound speed is nearly equal to the speed into the rail for a shot straight into the rail. This is off by a factor of two for what has been observed on real tables. Either I don't understand the plot or their analysis is completely broken. This loss factor was recently discussed and is the reason you can't get 10 lengths up and down the table.
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In the end they say the COR of ball-rail impact is 0.98, which is a bit too high. But I could be wrong
 
Pubo said:
In the end they say the COR of ball-rail impact is 0.98, which is a bit too high. But I could be wrong
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Dr. Dave has high speed videos on his YouTube channel. Under various conditions I think the highest actually measured is 0.56 or so. As I said, the authors of that paper got something horribly wrong.
 
nataddrho said:
I am not sure you meant to say what you did. A factor of two would mean the coefficient of restitution would be 0.5 or less, and the ball would rebound with half the speed? That doesn’t seem right.

From his conclusion section, the author states:
Combining some of the authors’ previous experi- mental results with the numerical solutions, the coef- ficient of restitution for the ball–cushion collision is determined as 0.98. In addition, the value for the sliding coefficient of friction is found to be 0.14.

The reason you can’t get 10 rail banks is due much more to the cloth friction than the cushion bounce. Imagine a table surface made of ice, how many rails do you think you could contact the ?
Click to expand...
 
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Bob Jewett said:
Dr. Dave has high speed videos on his YouTube channel. Under various conditions I think the highest actually measured is 0.56 or so. As I said, the authors of that paper got something horribly wrong.
Click to expand...
The highest is actually 91% on a slick table
 
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