Draw and Drag Draw

Jal said:
Yes. If the term "sliding" has become synonymous with "stun", that's fine with me (who cares!). But I'm not sure if it has, or if some feel the ball is doing something special with respect to the cloth at the stun stage.

If the cueball is struck at (1/2)R below center, ignoring some minor moderating effects such as vertical squirt and any initial bounce, the distance to natural roll would be 1.16 the distance to stun, or 16% more. At (2/5)R below center, the ratio would be 1.28. At (1/4)R, 1.63. And if struck at centerball, it would be infinity. So it changes quite rapidly.

I don't think your intent was to portray this to scale, but if you wanted to....

Jim
Click to expand...
Jim,
I wouldn't have known where to start to get those calculations, but they are VERY informative insofar as demonstrating why attempting a stun-roll-through with a below center hit is so hard.

I think diagrams to scale with hits at different heights would be very useful in demonstrating this.

Colin
 
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BWTadpole said:
...As long as there is friction, a sphere will stop sliding and begin to roll once it is traveling at 5/8ths its original speed.
Click to expand...
Sorry, but this is true only if it starts out with no topspin or backspin, i.e., a centerball hit. (And the figure is 5/7'ths for an ideal solid sphere.) If struck below center, it's less than 5/7'ths. If struck above center, it's more than 5/7'ths. If struck at (2/5)R above center with a ideal squirtless cue, it immediately starts out at natural roll.

Jim
 
JohnnyOzone said:
Nice job, man.
Click to expand...

Thanks. It's a work in progress, and these comments help a lot.

You could also use a stripe on the ball to show the same thing.
Click to expand...

Yeah, that's a good idea (I know because I had it too :) ), but I wonder if it would confuse the graphic.

The only nit I have to pick is the use of the term "stun run through"
This is a different type of shot than a draw drag shot - even one that only follows just a little bit.
Click to expand...

Yeah, you might hit a stun runthrough very close to centerball, maybe even a hair high, and not as softly. But it's still the same kind of shot - hit the CB low enough and/or hard enough so it doesn't gain full natural roll by the time it hits the OB.

For me, ANY shot with the type of action you are portraying (other than the cueball coming back toward you) I call a draw-drag shot.
Click to expand...

I think that's appropriate, since they're all similar shots that use the same principle - but they all have different desired outcomes, so it might be useful to have names for them.

pj
chgo
 
I think the diagram is pretty good.

Just a question for the group....

How many of you load up on english and hit normal shooting speed to accomplish these types of shots and how many of you fire balls in at warp speed and make subtle english adjustments (to offset friction)?

Just curious.

I was never really accurate with stun-follows, etc, until I started to stay at the center of the CB and warp them in.
 
Jal said:
Yes. If the term "sliding" has become synonymous with "stun", that's fine with me (who cares!). But I'm not sure if it has, or if some feel the ball is doing something special with respect to the cloth at the stun stage.
Click to expand...

As you've said elsewhere, stun is a specific case of sliding with a specific outcome (stop shot or carom on the tangent), but most people don't associate revolving with sliding, so "revolving while sliding" will probably continue to need more words to describe. Maybe I should replace "sliding" with "fully sliding".

If the cueball is struck at (1/2)R below center, ignoring some minor moderating effects such as vertical squirt and any initial bounce, the distance to natural roll would be 1.16 the distance to stun, or 16% more. At (2/5)R below center, the ratio would be 1.28. At (1/4)R, 1.63. And if struck at centerball, it would be infinity. So it changes quite rapidly.

I don't think your intent was to portray this to scale, but if you wanted to....
Click to expand...

I would like to if it's comprehensible - these numbers will help a lot (along with the concept of time vs. distance that Bob mentioned). Thanks to both of you.

Do you also know the relative distances the CB must travel before backspin rubs completely off (to become stun) when hit at different distances below center? I.e., if it takes one foot if hit at (1/4)R below center, would it take 1.63 feet if hit at (1/2)R below center?

pj
chgo
 
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SpiderWebComm said:
How many of you load up on english and hit normal shooting speed to accomplish these types of shots and how many of you fire balls in at warp speed and make subtle english adjustments (to offset friction)?

Just curious.

I was never really accurate with stun-follows, etc, until I started to stay at the center of the CB and warp them in.
Click to expand...

That's a workable technique as long as you're hitting straight in shots (so the CB is controlled) and as long as it doesn't matter how far the OB goes (it won't work very well for safeties or in 1 pocket).

The alternative is to just practice softer stun follows. One way is to visualize hitting a stop shot on an imaginary OB that's a little closer than the real one (so the CB picks up just a little forward roll before contact). The transition from stun (full slide) to full forward roll is pretty short, so the imaginary OB is pretty close to the real one, making this a pretty subtle adjustment most of the time. And it's a little more difficult than it sounds to adjust your stroke to an imaginary target. Takes practice.

pj
chgo
 
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SJDinPHX said:
PJ, All good player's use this shot often. I've heard it called "stun forward" or "kill forward', does it really need a name? If you can execute it properly, it can be stroked soft, firm, or warp speed with the same amount of roll after contact.
Nice graphic though, Colin would be proud of you.

Dick <----hits that shot well. ;)
Click to expand...

Dick, you obviously use a system to hit that shot well. You could not make it consistently well without a reliable system.

Patrick, don't use "stun forward or kill forward". Those are terms that went out of use before I started playing pool. :D

I like "draw drag follow" and the graphics illustrate it just fine. I might change the length of the arrows to denote speed, though.
Longer arrows- faster revolution speed.
Shorter arrows-slower revolution speed.
I might even put two sets of arrows on each ball instead of one......depending on how it looked.

JoeyA
 
JoeyA said:
Dick, you obviously use a system to hit that shot well. You could not make it consistently well without a reliable system.
Click to expand...

In fact, there is such a system - or method. See my earlier post.

Patrick, don't use "stun forward or kill forward". Those are terms that went out of use before I started playing pool. :D
Click to expand...

How could those terms have gone out of use before English was invented?

I like "draw drag follow" and the graphics illustrate it just fine. I might change the length of the arrows to denote speed, though.
Longer arrows- faster revolution speed.
Shorter arrows-slower revolution speed.
Click to expand...

Didn't I do that?

pj
chgo
 
Didn't I do that? pj chgo[/QUOTE said:
Patrick,
Sorry about missing the different length arrows. Maybe you could make them a lot thicker or not.
JoeyA
Click to expand...
 
dr_dave said:
Patrick,

Excellent diagram! Are you working on a book?
Click to expand...

No, just a hobby. I used to use diagrams like this in a class I taught, but now just use them to help explain things to people who are interested.

The only suggestion I have is to add straight arrows above the balls, of changing length, to indicate how translational speed varies with the angular speed. For example, see:
Regards,
Dave
Click to expand...

Thanks, Dave. I should have known you'd already have something like this. You're a fount of info.

pj
chgo
 
Patrick Johnson said:
Thanks, Dave. I should have known you'd already have something like this. You're a fount of info.
Click to expand...
I like yours better, especially if you add the straight arrows of changing length. Please share your new diagram if you make any changes.

Regards,
Dave
 
Patrick Johnson said:
...
Do you also know the relative distances the CB must travel before backspin rubs completely off (to become stun) when hit at different distances below center? I.e., if it takes one foot if hit at (1/4)R below center, would it take 1.63 feet if hit at (1/2)R below center?
Click to expand...
Patrick,

Sorry for the delay; just didn't have much time yesterday. Here's some relevant calculations. The table showing comparative stun distances should answer your question, I think. The formulas are included for "completeness" and in case anyone would care to check the math. They are such that the offsets (b/R) are treated as positive fractions, even though they are for below center hits. All of the numbers are for a ball struck with a level and ideal squirtless cue. Actual distances will vary a bit.


Distance to stun formula:

Ds = [V^2/(ug)][b/r][1 - (1/2)(b/R)]

where V^2 is the cueball's speed squared, u is the coefficient of sliding friction (approx. 0.2), g is the gravitational acceleration constant, and b/R is the tip offset (contact point) below center. If V is in units of feet/sec, then g is approx. 32.16 feet/sec/sec. When comparing stun distances at different offsets but at fixed cueball speeds, only the factor [b/r][1 - (1/2)(b/R)] changes. Listed below are its values at selected offsets ("..." means repeat last digit):.

b/R__[b/r][1 - (1/2)(b/R)]

0____0.00000....

1/5__0.18000....

1/4__0.21875000...

1/3__0.27777....

2/5__0.32000....

1/2__0.37500....


Table of comparative distances to stun at offsets (b/R) below center. For instance, when striking at (2/5)R below center (see top row), the distance to stun will be 1.78 X the distance when striking at (1/5)R below center, and 1.46 X the distance when striking at (1/4)R below center. It's assumed that cue speed is adjusted so that the cueball has the same velocity after being struck at every offset.

b/R__0__1/5__1/4__1/3__2/5__1/2

0____1__inf___inf___inf__inf___inf

1/5__0___1___1.22_1.54_1.78_2.08

1/4__0_.823___1___1.27_1.46_1.71

1/3__0_.648_.787___1___1.15_1.35

2/5__0_.562_.684__.868__1___1.17

1/2__0_.480_.583__.741_.853__1

To convert to actual distances, and assuming the coefficient of sliding friction u=0.2, hitting at (2/5)R below center provides a handy rule of thumb. If the cueball's speed is in units of miles/hour, square it and divide by 10. This will be the distance to stun in feet. For example, lag speed is about 5 mph, so it should reach stun at about 5X5/10 or 2.5 feet. Driving it again at lag speed but striking at (1/4)R below center instead, divide this by 1.46 as given in the above table (= 1.66 feet). Doubling the speed increases the distance by a factor of 4. Halving the speed reduces it by a factor of 1/4.



Distance to Natural Roll formula:

Dr = [25/98][V^2/(ug)][24/25 + 2(b/R) - (b/R)^2]

When comparing distances at different offsets but at fixed cueball speeds, only the factor [24/25 + 2(b/R) - (b/R)^2] changes. Listed below are its values at selected offsets.

b/R__[24/25 + 2(b/R) - (b/R)^2]

0____.96000.....

1/5__1.2000.....

1/4__1.3975000....

1/3__1.51555....

2/5__1.60000....

1/2__1.71000....


Table of comparative distances to natural roll at offsets (b/R) below center. For instance, when striking at (2/5)R below center, the distance to natural roll will be 1.67 X the distance when striking at centerball, and 1.33 X the distance when striking at (1/5)R below center. It's assumed that cue speed is adjusted so that the cueball has the same velocity after being struck at every offset.

b/R__0___1/5___1/4___1/3___2/5___1/2

0____1___1.25__1.46__1.58__1.67__1.78

1/5_.800___1___1.16__1.26__1.33__1.42

1/4_.687_.859___1____1.08__1.14__1.22

1/3_.633_.792__.922___1____1.06__1.13

2/5_.600_.750__.873___.947___1____1.07

1/2_.561_.702__.817___.886__.936___1


Ratio of (Distance to Natural Roll)/(Distance to Stun) at offsets (b/R) below center. This is relatively independent of cueball speed.

Dr/Ds = [25/98][24/25 + 2(b/R) - (b/R)^2]/[(b/R) - (1/2)(b/R)^2]

b/R__Dr/Ds

0____inf

1/5__1.70

1/4__1.63

1/3__1.39

2/5__1.28

1/2__1.16


Jim
 
Jal said:
Patrick,

Sorry for the delay; just didn't have much time yesterday. Here's some relevant calculations. The table showing comparative stun distances should answer your question, I think. The formulas are included for "completeness" and in case anyone would care to check the math. They are such that the offsets (b/R) are treated as positive fractions, even though they are for below center hits. All of the numbers are for a ball struck with a level and ideal squirtless cue. Actual distances will vary a bit.


Distance to stun formula:

Ds = [V^2/(ug)][b/r][1 - (1/2)(b/R)]

where V^2 is the cueball's speed squared, u is the coefficient of sliding friction (approx. 0.2), g is the gravitational acceleration constant, and b/R is the tip offset (contact point) below center. If V is in units of feet/sec, then g is approx. 32.16 feet/sec/sec. When comparing stun distances at different offsets but at fixed cueball speeds, only the factor [b/r][1 - (1/2)(b/R)] changes. Listed below are its values at selected offsets ("..." means repeat last digit):.

b/R__[b/r][1 - (1/2)(b/R)]

0____0.00000....

1/5__0.18000....

1/4__0.21875000...

1/3__0.27777....

2/5__0.32000....

1/2__0.37500....


Table of comparative distances to stun at offsets (b/R) below center. For instance, when striking at (2/5)R below center (see top row), the distance to stun will be 1.78 X the distance when striking at (1/5)R below center, and 1.46 X the distance when striking at (1/4)R below center. It's assumed that cue speed is adjusted so that the cueball has the same velocity after being struck at every offset.

b/R__0__1/5__1/4__1/3__2/5__1/2

0____1__inf___inf___inf__inf___inf

1/5__0___1___1.22_1.54_1.78_2.08

1/4__0_.823___1___1.27_1.46_1.71

1/3__0_.648_.787___1___1.15_1.35

2/5__0_.562_.684__.868__1___1.17

1/2__0_.480_.583__.741_.853__1

To convert to actual distances, and assuming the coefficient of sliding friction u=0.2, hitting at (2/5)R below center provides a handy rule of thumb. If the cueball's speed is in units of miles/hour, square it and divide by 10. This will be the distance to stun in feet. For example, lag speed is about 5 mph, so it should reach stun at about 5X5/10 or 2.5 feet. Driving it again at lag speed but striking at (1/4)R below center instead, divide this by 1.46 as given in the above table (= 1.66 feet). Doubling the speed increases the distance by a factor of 4. Halving the speed reduces it by a factor of 1/4.



Distance to Natural Roll formula:

Dr = [25/98][V^2/(ug)][24/25 + 2(b/R) - (b/R)^2]

When comparing distances at different offsets but at fixed cueball speeds, only the factor [24/25 + 2(b/R) - (b/R)^2] changes. Listed below are its values at selected offsets.

b/R__[24/25 + 2(b/R) - (b/R)^2]

0____.96000.....

1/5__1.2000.....

1/4__1.3975000....

1/3__1.51555....

2/5__1.60000....

1/2__1.71000....


Table of comparative distances to natural roll at offsets (b/R) below center. For instance, when striking at (2/5)R below center, the distance to natural roll will be 1.67 X the distance when striking at centerball, and 1.33 X the distance when striking at (1/5)R below center. It's assumed that cue speed is adjusted so that the cueball has the same velocity after being struck at every offset.

b/R__0___1/5___1/4___1/3___2/5___1/2

0____1___1.25__1.46__1.58__1.67__1.78

1/5_.800___1___1.16__1.26__1.33__1.42

1/4_.687_.859___1____1.08__1.14__1.22

1/3_.633_.792__.922___1____1.06__1.13

2/5_.600_.750__.873___.947___1____1.07

1/2_.561_.702__.817___.886__.936___1


Ratio of (Distance to Natural Roll)/(Distance to Stun) at offsets (b/R) below center. This is relatively independent of cueball speed.

Dr/Ds = [25/98][24/25 + 2(b/R) - (b/R)^2]/[(b/R) - (1/2)(b/R)^2]

b/R__Dr/Ds

0____inf

1/5__1.70

1/4__1.63

1/3__1.39

2/5__1.28

1/2__1.16


Jim
Click to expand...

Wow. Thanks, Jim. That's way more info than I deserve, and it will all be very helpful.

pj
chgo
 
SpiderWebComm said:
I think the diagram is pretty good.

Just a question for the group....

How many of you load up on english and hit normal shooting speed to accomplish these types of shots and how many of you fire balls in at warp speed and make subtle english adjustments (to offset friction)?

Just curious.

I was never really accurate with stun-follows, etc, until I started to stay at the center of the CB and warp them in.
Click to expand...
I think stun through shots are more prevalent in snooker than pool so I've seen a lot of snooker pros executing these and I try to play them pretty much the same way.

i.e. Firm speed hitting dead center of a touch above it depending on the distance to the OB. If warp speed mean getting near break speed then I'd say I almost never hit one at that speed. Heaps of speed can magnify errors I think so it seems to be most player who play these hit them as hard as they need to without letting the CB pick up much spin from the cloth, but no harder.

Colin ~ Reviver of dead threads.
 
dr_dave said:
Please share your new diagram if you make any changes.
Click to expand...

I will, and you're welcome to reproduce and use any of mine for any non-commercial purpose. So is anybody else.

pj
chgo
 
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