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Ross
06-10-2003, 01:35 PM
Hi CCB'ers,

Since these terms/concepts are unfamiliar to newer players and sometimes confused by more experienced ones, I have created a webpage to serve as an Introduction to Throw, Squirt, and Swerve. For each term there is a definition, a diagram, some explanation of the causes, and a list of some of the factors that increase or decrease the size of these effects.

For some of you this will be old hat, but others of you MAY find it useful. It was designed to be user-friendly, so there are simplifications and omissions.

Anyway, I hope some of you will look it over and let me know what you think. It is a first draft, so I won't be offended if you fire away! /ccboard/images/graemlins/grin.gif

Here is the link:

http://www.duke.edu/~rulmer/poolterms.htm (be sure to include the htm part)


RossNC ~ hoping the link works, and the pictures appear, since I used Word to "Save as html." Some of you know what a humongous and convoluted set of microtrash, err, microsoft code this creates.

SpiderMan
06-10-2003, 01:59 PM
Ross,

It's a good idea, and you have some nice diagrams. I only made it through the first page so far, but I thought I'd stop and document this before I forget:

You made the statement: "larger cut angle = less throw"

Unless you have an irrefutable source, I think you should investigate further. I seem to remember reading more than one source implying that the throw is maximum somewhere around a half-ball hit, and less for either a wider or narrower cut angle. I also seem to remember personally verifying this for frozen-ball throw examples.

Next, the statement: "more cue ball side spin relative to cue ball speed = more throw"

I'd say this is not true if the side spin is "outside english" as referenced to the cut angle. Adding a little outside to the CB can diminish or eliminate the throw. This distinction should somehow be made. The same applies to this statement in the next section:

"throw is maximized with a slow full hit with maximum sidespin using dirty balls"

Again, it depends on the direction of the sidespin, and also what did you mean by full hit? That could be interpreted as a very narrow cut angle, which then again contradicts the first quotation. Of course, a full hit results in no contact throw and only english throw, if that's what you meant.

Please take these comments as constructive, you did welcome a little nitpicking.

SpiderMan

tateuts
06-10-2003, 02:15 PM
Ross,

Excellent - really defines most of the forces at work.

Chris

Deeman
06-10-2003, 02:23 PM
Ross,

Nice post. Do you want to say anything about cue speed and squirt? I mean, if I'm hitting harder I compensate more. Now, you may say I'm just reducing the swerve back on-line with the target, but it seems like more squirt to me.

Qtec
06-10-2003, 02:31 PM
Brilliant! This should save a lot of confusion. Well done. Just one thing.
[ QUOTE ]
High speed photography by Jewett and others have found the time of contact between cuestick and cue ball to be about .001 seconds or a slightly more.

<hr /></blockquote>
Wouldnt you agree that this all depends on what kind of tip you use [hard/ soft]and the way you hit the QB .


Qtec

Ross
06-10-2003, 03:43 PM
<blockquote><font class="small">Quote SpiderMan:</font><hr> Ross,

It's a good idea, and you have some nice diagrams. I only made it through the first page so far, but I thought I'd stop and document this before I forget:

You made the statement: "larger cut angle = less throw"

Unless you have an irrefutable source, I think you should investigate further. I seem to remember reading more than one source implying that the throw is maximum somewhere around a half-ball hit, and less for either a wider or narrower cut angle. I also seem to remember personally verifying this for frozen-ball throw examples.
<hr /></blockquote>
SpiderMan, I'm glad you picked that up.

When I wrote that statement I was thinking of the throw effect due to sidespin on the cueball. (I said it was a first draft! /ccboard/images/graemlins/crazy.gif) For spin-induced-throw, the larger the cut angle the less effect cb spin has on throw.

For cb with no sidespin (collision induced throw), I think you may be right: maximum throw at 1/2 ball hit. But I think I've seen empirical results that actually say that CIT is maximal for thin hits (Capelle maybe?) I will research this and correct it.

While Ron Shepard (billiard physics guru par excellance for those of you who don't know) doesn't like to distinguish between SIT and CIT, I think they are still useful concepts. For example, I seemed to need them in this reply.
[ QUOTE ]


Next, the statement: "more cue ball side spin relative to cue ball speed = more throw"

I'd say this is not true if the side spin is "outside english" as referenced to the cut angle. Adding a little outside to the CB can diminish or eliminate the throw. This distinction should somehow be made. The same applies to this statement in the next section:
<hr /></blockquote>

I'm realizing how tricky the wording can be. We agree I think on what happens -I just have to work on the wording.

I meant "more cue ball side spin relative to cue ball speed" = greater alteration of the ob path (when compared to a hit with no side spin). I will work on the wording of this as well.
[ QUOTE ]

"throw is maximized with a slow full hit with maximum sidespin using dirty balls"

Again, it depends on the direction of the sidespin, and also what did you mean by full hit? That could be interpreted as a very narrow cut angle, which then again contradicts the first quotation. Of course, a full hit results in no contact throw and only english throw, if that's what you meant.
<hr /></blockquote>

That is what I meant. More rewording here too. /ccboard/images/graemlins/tongue.gif
[ QUOTE ]

Please take these comments as constructive, you did welcome a little nitpicking.

SpiderMan <hr /></blockquote>

And you believed me?! /ccboard/images/graemlins/grin.gif

Ross
06-10-2003, 03:49 PM
<blockquote><font class="small">Quote Deeman:</font><hr> Ross,

Nice post. Do you want to say anything about cue speed and squirt? I mean, if I'm hitting harder I compensate more. Now, you may say I'm just reducing the swerve back on-line with the target, but it seems like more squirt to me. <hr /></blockquote>

Thanks, Deeman. From what I've been told by the physics gurus, the greater compensation for harder hits IS just due to the reduced swerve. I know it doesn't feel that way, but I think that is because we just don't recognize the few millimeters of swerve that we unconsciously compensate for all the time on normal speed shots.

Of course, the physicists may be wrong...

Ross
06-10-2003, 03:59 PM
<blockquote><font class="small">Quote Qtec:</font><hr> Brilliant! This should save a lot of confusion. Well done. Just one thing.
&lt;/font&gt;&lt;blockquote&gt;&lt;font class="small"&gt;Quote:&lt;/font&gt;&lt;hr /&gt;
High speed photography by Jewett and others have found the time of contact between cuestick and cue ball to be about .001 seconds or a slightly more.

<hr /></blockquote>
Wouldnt you agree that this all depends on what kind of tip you use [hard/ soft]and the way you hit the QB .


Qtec <hr /></blockquote>

Qtec, thanks for the feedback. Based on the high speed photography done by Jewett and others (the so-called "Jacksonville Project" extensively discussed over in RSB) the contact time is surprisingly constant regardless of stroke, even though it doesn't feel that way. The tip hardness might have had a small effect, but all contact times were well under .002 seconds, I think. They used all kinds of cues and tips, and even had a world-class 3-cushion billiard player try his several types of specialty strokes. I think this is all correct, but it is from memory, so as they say, caveat emptor.

Rod
06-10-2003, 04:08 PM
Ross,
Good first round draft. It needs a little work that has been mentioned. I could add but it starts becoming to wordy and complicated. Just keep it simple as you have done.
Now when someone needs a basic understanding we will just point them to your site.

Rod

eg8r
06-10-2003, 04:12 PM
Ross,

Thanks for the site. It is nice to have a reference to go look at when I forget details. I almost always get these mixed up and the site is helpful to go back and make sure I understand what is being discussed.

Great job,

eg8r

Eric.
06-10-2003, 04:42 PM
Looks good, Ross! I think that would clear it up for anyone looking for the answers to your topic.


Eric &gt;going to the Open?

Scott Lee
06-11-2003, 01:03 AM
<blockquote><font class="small">Quote Qtec:</font><hr>
Wouldnt you agree that this all depends on what kind of tip you use [hard/ soft]and the way you hit the QB .


Qtec <hr /></blockquote>

Qtec...Tip hardness and stroke speed have little or no effect on the length of time the tip is in contact with the CB. Much the same as the SIZE of the contact point between the tip and CB (regardless of tip size) remain constant, at appx. 1/8 of an inch (or the size of the red circle on a red circle cueball). Even when you break hard and it looks like there is a big blue dot on the CB, this is just more chalk dust blowing back off the tip. The actual contact size remains minute! Ross is correct about the "Jacksonville tapes" experiments done by Jewett, et al.

Scott Lee

Fred Agnir
06-11-2003, 06:26 AM
<blockquote><font class="small">Quote Qtec:</font><hr> Brilliant! This should save a lot of confusion. Well done. Just one thing.
[ QUOTE ]

High speed photography by Jewett and others have found the time of contact between cuestick and cue ball to be about .001 seconds or a slightly more.

<hr /></blockquote>
Wouldnt you agree that this all depends on what kind of tip you use [hard/ soft]and the way you hit the QB .


Qtec <hr /></blockquote>I think it's fair to say "about .001 sec" across the board. At least three factors showed an affect on the contact time: shot speed, tip hardness, eccentricity. IIRC, the range of tip contact time was from 1 to 2 milliseconds. Tip hardness wasn't reported to have any more of a major impact to contact time compared to shot speed or eccentricity.

Fred

Fred Agnir
06-11-2003, 06:43 AM
<blockquote><font class="small">Quote Ross:</font><hr> Hi CCB'ers,

Since these terms/concepts are unfamiliar to newer players and sometimes confused by more experienced ones, I have created a webpage to serve as an Introduction to Throw, Squirt, and Swerve. <hr /></blockquote>I think this was excellent. If I have a suggestion, it would be to separate the definitions from the physics. That is, one page could be "what they are" while linked to a page that says "why they are."

The debate will always continue as to "why they are," but at least we'd all be debating using the same "what they are" definitions.

Fred

pooltchr
06-11-2003, 06:58 AM
Hi Ross,
Great post! With your permission, I would like to use the diagrams in my teaching program. I see the terms often used somewhat interchangably (and mistakenly, I might add) and this will help differentiate them.
On another note, are you going to be back in Boone again this year?
Steve

Rich R.
06-11-2003, 11:46 AM
Very nice explanation Ross.

I just have one question.

How do you control Throw, Squirt and Swerve? /ccboard/images/graemlins/confused.gif

I guess I'll go ahead and answer my own question, before others beat me to it.

There are three ways to control Throw, Squirt and Swerve.
1. Practice.
2. Practice.
3. Practice.

/ccboard/images/graemlins/tongue.gif /ccboard/images/graemlins/blush.gif /ccboard/images/graemlins/confused.gif /ccboard/images/graemlins/grin.gif

RedHell
06-11-2003, 12:30 PM
<blockquote><font class="small">Quote Rich R.:</font><hr> Very nice explanation Ross.

I just have one question.

How do you control Throw, Squirt and Swerve? /ccboard/images/graemlins/confused.gif

I guess I'll go ahead and answer my own question, before others beat me to it.

There are three ways to control Throw, Squirt and Swerve.
1. Practice.
2. Practice.
3. Practice.

/ccboard/images/graemlins/tongue.gif /ccboard/images/graemlins/blush.gif /ccboard/images/graemlins/confused.gif /ccboard/images/graemlins/grin.gif <hr /></blockquote>

Some would say there is four...

1. Practice.
2. Practice.
3. Practice.
4. Predator.

Tho I'm not one of them ! /ccboard/images/graemlins/grin.gif

Ross
06-11-2003, 04:12 PM
OK, version 2 of this document is now up.
http://www.duke.edu/~rulmer/poolterms.htm (same link as before)

Great suggestions from everyone. I found it difficult to be precise without getting overly complicated. (After all this is supposed to be a user friendly introduction to the terms.)

So, in an attempt to satisfy two masters (simplicity and more detailed precision) I put the definitions on one page with links to the more detailed information.

Also, in discussing throw, I realized that we really use the term regularly in different senses.

Sometimes it is used to describe the effect of the ob path deviating from the line of centers. For example, "You have to cut an ob slightly more than the ghost ball would predict because of throw."

But throw is also used in another similar, but different, sense - as a verb to describe altering the ob ball path by using side spin - "I couldn't see enough of the ball, so I used outside english to throw the ball into the pocket."

In my first draft, I used these terms interchangeably and this led to the misleading statements picked up by Spiderman. I worked on this, and so it is now more correct, but alas, now we have two definitions of throw. What is a poor bloke to do? /ccboard/images/graemlins/crazy.gif

Anyway, again feel free to comment. No, really... I mean it....really... /ccboard/images/graemlins/grin.gif

Qtec
06-11-2003, 04:17 PM
Scott, i didnt mention size of cue tip at all , I was talking about hard/soft tips. Texture not size. More importantly ,[ which you didnt mention ] i was talking about how the QB is struck. In my opinion its all about acceleration of the cue through the ball. I checked out the RSB and they are still discussing the tapes. One guy says that they were not done properly.Its still in the air.

From the éxperiment'i found this, [ QUOTE ]
"[Tip contact] time can be easily measured from the video mentioned
above for various speeds, tips, and amounts of side spin, and it is
seen to vary from about 0.8 milliseconds to 2.0 milliseconds."
<hr /></blockquote>
Is it not possible that the extra 1.2 milliseconds can make all the difference? A lot of people are asking "why can i feel the difference when i hit it sweet". They feel that they have a longer contact with the QB. I am not yet convinced .
Just in case you didnt know, the "Pause" method was first introduced by snooker guru Frank Callan. His star pupil was Steve Davis.When Steve won everything in sight in snooker a lot of players took it on .eg[ Denis Taylor]. This was 24 years ago. I,m surprised people haven,t heard about it before.


Qtec

Ross
06-11-2003, 04:20 PM
<blockquote><font class="small">Quote pooltchr:</font><hr> Hi Ross,
Great post! With your permission, I would like to use the diagrams in my teaching program. I see the terms often used somewhat interchangably (and mistakenly, I might add) and this will help differentiate them.
On another note, are you going to be back in Boone again this year?
Steve <hr /></blockquote>

Thanks, Steve. And yes you are welcome to use the diagrams, text, or any combination.
I had a blast last year at Chris's. Randy, Leslie, Chris, you and some of the others made it an thoroughly enjoyable class. I will definitely try to go to Randy's training at Boone again this year if he is doing an advanced class.

heater451
06-11-2003, 04:27 PM
Good deal, Ross.

I was going to start adding similar info to my Tripod site, but now maybe I'll just add your link.

Of course, that's all dependent on two things: 1) You don't mind me linking, and 2) I actually take the time and energy to do it. . . .



========================

Ross
06-11-2003, 04:30 PM
<blockquote><font class="small">Quote heater451:</font><hr> Good deal, Ross.

I was going to start adding similar info to my Geocities site, but now maybe I'll just add your link.

Of course, that's all dependent on two things: 1) You don't mind me linking, and 2) I actually take the time and energy to do it. . . .



======================== <hr /></blockquote>

Don't mind. Can't help you with the second one.. /ccboard/images/graemlins/smirk.gif

TonyM
06-11-2003, 04:42 PM
Well done!

I anticipated that there would be more errors. But you seem to have done your home work very well!

I tend to agree with Ron Shepard that there should be little or no distinction between Contact induced throw (CIT), and Sidespin induced throw (SIT).

His concept allows you to understand why a stun shot (no top or backspin, ie: a sliding cueball) would maximize throw (for either CIT or SIT). And why the addition of a bit of follow or draw can reduce the magnitude of throw.

While the old idea of two seperate effects acting like the "gear effect" don't explain or predict this behavior.

The idea that squirt is essentially independant of shot speed is controvertial for many players I'm sure.

I had the opportunity to suggest to the folks at Predator (Clawson cues) to put this idea to the test. They used Iron Willie, and a slick non-cloth playing surface (like a melamine type of material IIRC) to eliminate the effect of swerve.

The set-up used a single tip ball offset location, with the only variable being shot speed.

Alan McCarty (of Clawson cues) was kind enough to do the test at my suggestion, and was certain that it would show that squirt was definitely dependant on speed.

Well, he was suprised!

He found virually no difference in the final path of the cueball through a large range of shot speeds (from very slow to break speed!).

So to me, this means that what most players observe as speed dependant effects when using sidespin are really the effect of dimished swerve when speed is increased (and the reverse - enhanced swerve at lower speeds).

You can also see this when you play on a table that has just been recovered with brand new Simonis. It "appears" for all the world like you are getting more squirt. In fact, squirt remains unchanged, but you are actually seeing less swerve. Hence the squirt is more apparent.

When we play on real cloth and normal conditions, virtually every shot with sidespin requires that we estimate the effects of squirt and swerve into a single final aim line. You might even call this combined effect "Squirve" or something like that.

But understanding the two effects seperately can allow the player to extrapolate the required aim for shots that are jacked-up with sidespin (swerve dominates) or with a change in table conditions (like the new cloth effect described above).

One nit:

The suggestion that swerve is always present on a shot with sidespin is dependant on the presence of cue elevation. It is possible to get a truly level cue in some circumstances (when the butt end is onto the table bed and not over a rail) and you can even get "reverse" swerve if you so desire.

Otherwise, A well done primer!

Tony

TonyM
06-11-2003, 04:51 PM
I had this tested by the guys at Predator using Iron Willie, and a slippery non-cloth surface to eliminate swerve. The result?

Speed did NOT effect the squirt angle to any measurable degree!

So while I agree that it "seems" like it does, what this really means is that we are not aware of the magnitude of the swerve effect at different speeds.

Try some shots with increased cue elevation (like a low hit with sidespin with the cue ball a few inches off of a rail) and with different speeds and it starts to make more sense.

Tony

Ross
06-11-2003, 04:59 PM
<blockquote><font class="small">Quote TonyM:</font><hr> Well done!

I anticipated that there would be more errors. But you seem to have done your home work very well!


Tony <hr /></blockquote>

Thanks, Tony. Momma didn't raise no dummy! /ccboard/images/graemlins/cool.gif



Ross ~ trying his best to ignore the condescension

TonyM
06-11-2003, 05:01 PM
"Next, the statement: "more cue ball side spin relative to cue ball speed = more throw"

"I'd say this is not true if the side spin is "outside english" as referenced to the cut angle. Adding a little outside to the CB can diminish or eliminate the throw."

This was what I was getting at in the cutting balls in thread Spiderman.

For outside english to "eliminate" throw, you have to add just the right amount of sidespin so that the cueball has, in effect, "natural roll" about the vertical axis, so that the surface of the cueball "rolls off" of the surface of the object ball without actually rubbing across it.

This is a specific amount of sidespin .

If you add additional sidespin, then you create a frictional force on the surface that will change the direction of the object ball path (ie: throw opposite to the direction of the applied sidespin).

If you have less sidespin, then you will create a frictional force that acts lin the same direction as the no-sidespin case.

Looking at the problem from the perspective of a "sliding surface friction" problem as suggested by Ron Sheppard in APAPP resolves this situation imo.

It suggests that the practice of adding sidespin to try and eliminate throw becomes more problematic when the ball surface friction increases.

It predicts that when the balls are very sticky or dirty, a small error in the amount of sidespin applied can have a bigger effect on the final object ball path that most people would assume.

Tony

heater451
06-11-2003, 05:03 PM
<blockquote><font class="small">Quote TonyM:</font><hr>. . .But understanding the two effects seperately can allow the player to extrapolate the required aim for shots that are jacked-up with sidespin (swerve dominates) or with a change in table conditions (like the new cloth effect described above).

One nit:

The suggestion that swerve is always present on a shot with sidespin is dependant on the presence of cue elevation. It is possible to get a truly level cue in some circumstances (when the butt end is onto the table bed and not over a rail) and you can even get "reverse" swerve if you so desire.

Otherwise, A well done primer!

Tony<hr /></blockquote>Tony, to you think a swerve difference would exist, between balls hit with difference english styles--that is, between say, two tips right w/ cue parallel to the CB centerline, and two tips w/ back-hand english?

Do you think a machine could even be set up to mimic a BHE shot?--It would seem that a BHE line, with the straight, mechanical stroke, would cause the shot to become a parallel-line shot with an altered aim/path.



=======================

TonyM
06-11-2003, 05:06 PM
Hi Ross!

"Sometimes it is used to describe the effect of the ob path deviating from the line of centers. For example, "You have to cut an ob slightly more than the ghost ball would predict because of throw."

But throw is also used in another similar, but different, sense - as a verb to describe altering the ob ball path by using side spin - "I couldn't see enough of the ball, so I used outside english to throw the ball into the pocket."

Ross I don't really see a distinction here and wouldn't change anything imo.

To me "Throw" refers simply to the effect of changing the object ball path by a change in the sliding surface friction between the cueball and the object ball.

To me the terms are one and the same. It simply depends on the useage.

Good job!

Tony

TonyM
06-11-2003, 05:10 PM
"Ross ~ trying his best to ignore the condescension"

Oops! Sorry Ross, no offense intended. seriously!
There was no intent at condescension.

What I meant was that most discussions here about squirt and swerve and throw show that most people (and clearly you don't fit in that category) have the terms backwards, or mix them up etc.

I was pleasantly surprised!

Good job again.

Tony

Scott Lee
06-11-2003, 08:08 PM
<blockquote><font class="small">Quote Qtec:</font><hr> Scott, i didnt mention size of cue tip at all , I was talking about hard/soft tips. Texture not size. More importantly ,[ which you didnt mention ] i was talking about how the QB is struck. In my opinion its all about acceleration of the cue through the ball. I checked out the RSB and they are still discussing the tapes. One guy says that they were not done properly.Its still in the air.

From the éxperiment'i found this, &lt;/font&gt;&lt;blockquote&gt;&lt;font class="small"&gt;Quote:&lt;/font&gt;&lt;hr /&gt;
"[Tip contact] time can be easily measured from the video mentioned
above for various speeds, tips, and amounts of side spin, and it is
seen to vary from about 0.8 milliseconds to 2.0 milliseconds."
<hr /></blockquote>
Is it not possible that the extra 1.2 milliseconds can make all the difference? A lot of people are asking "why can i feel the difference when i hit it sweet". They feel that they have a longer contact with the QB. I am not yet convinced .
Qtec

<hr /></blockquote>

Qtec...Reread my post. The FIRST words are "tip hardness
doesn't matter". There is not any significant tip compression during the stoke regardless of what hardness of tip you use. As for your statement about speed of stroke...I think you're not thinking clearly about exactly what a millisecond is. That's 1/1000th of a second. It's impossible for a human being to regulate anything that short. That's why they used the high-speed photography, which was taking pictures at 4000 frames a second. A second in video is measured by 40 frames...so this was 100x faster, and with very high resolution. The overall examinations showed that the average time a tip was in contact with the cueball was around 4/1000th's of a second.
Another 1/1000th either way would make little or no discernable difference...and you certainly couldn't "feel", nor control that difference.

Scott Lee

Ross
06-11-2003, 09:25 PM
No problem - we're cool. /ccboard/images/graemlins/wink.gif

Qtec
06-12-2003, 05:49 AM
Scott, this was my original question, [ QUOTE ]
Wouldnt you agree that this all depends on what kind of tip you use [hard/ soft]and the way you hit the QB .

<hr /></blockquote>
This was your repy
[ QUOTE ]
Qtec...Tip hardness and stroke speed have little or no effect on the length of time the tip is in contact with the CB <hr /></blockquote>

This is what B.Jewett has to say, [ QUOTE ]
Some extreme spin shots seem to hit the cue ball twice without a miscue.
Contact time increases on softer shots , for softer tips and with more eccentric hits, BUT THESE ARE NOT REALLY SURPRISES . <hr /></blockquote>

There is a difference. You can FEEL it.
In a lot of sports you deal in milliseconds . How is it possible that A .Agassi [tenis] can return serves at Wimbledon when the ball is travelling at 230km p.h. Considering that he has to see the direction ,judge the bounce, get his body in the right position, get his racket back and then hit the ball . What about downhill sking? You dont have a lot of time to think.
You can blidfold a pro golfer and just by FEEL he can tell you if the ball he hit was the normal ball he uses or not . Even with swing speeds in excess of 100 miles p.h.



Qtec

Fred Agnir
06-12-2003, 06:20 AM
<blockquote><font class="small">Quote Qtec:</font><hr> Is it not possible that the extra 1.2 milliseconds can make all the difference<hr /></blockquote>The longer contact time is due to off-center hits, which is predictable. The extra time is due to the cueball rotating while the tip remains in contact. Center ball hits, the cueball simply leaves the the tip in that .001 sec. contact time. 1msec to 1.3msec was the range for hundreds of shots. To my understanding, that was true for all tip hardness ranges. Off center hits and *very slow* strokes increased the contact time. Very slow strokes could be infringing on the push shot rule. The fact that you have to go *slower* to achieve a longer contact time should answer all questions regarding "accelerating through the shot."

Secondly, the person saying that the experiments were done incorrectly has never been specific on how he would do things differently. I'd take his opinion with more than a grain of salt.

Fred

Fred Agnir
06-12-2003, 06:28 AM
<blockquote><font class="small">Quote heater451:</font><hr> []Tony, to you think a swerve difference would exist, between balls hit with difference english styles--that is, between say, two tips right w/ cue parallel to the CB centerline, and two tips w/ back-hand english?<hr /></blockquote>I guess I don't understand the question. When you say "back hand english" I'm thinking you mean the Carabao style or what I call "dynamic back hand engish." Regular backhand english would get the same swerve curve as a standard stroked english shot.

Fred

TonyM
06-13-2003, 12:03 AM
"Tony, do you think a swerve difference would exist, between balls hit with difference english styles--that is, between say, two tips right w/ cue parallel to the CB centerline, and two tips w/ back-hand english?"

Hi Heater. I'm assuming like Fred, that to you, BHE refers to something that you do "on the fly" at the last moment with the cue stick?

Regardless, the amount of "swerve" that you will get will depend only on the actual amount of offset of the tip on the ball, the angle of the cue at impact (vertically, not horizontally) and the shot speed. If you get the same conditions outlined above with both techniques, then yes, you would get the same amount of swerve.

You would also get the same amount of squirt. But the new cue angle produced by the BHE pivoting about the bridge hand would mask the amount of squirt, effectively compensating for it.

This assumes that the cue has a pivot point somewhere in the vicinity of your bridge length of course!

The problem with comparing "Dynamic BHE" (Fred's term that I like a lot) with standard english is that you never actually know where you really hit the cueball!

To compare, you would need a training ball and compare the chalk marks.

"Do you think a machine could even be set up to mimic a BHE shot?--It would seem that a BHE line, with the straight, mechanical stroke, would cause the shot to become a parallel-line shot with an altered aim/path."

A "Dynamic BHE" shot (there's that term again, gotta love it!) cannot be duplicated by a machine that restricts the cue's lateral movement like Iron Willie. You can only move the cue in a straight line (laterally).

But of course you could simply find out what the final cue line would be and set the cue to stroke down that line.

Personally, I don't think that there is much difference between the "aim and pivot" technique (aim with centerball, pivot the cue to get the sidespin, and then stroke it straight) and the "Dynamic BHE" technique (which could be called "aim and swerve at the last moment!") as far as the cueball is concerned.

If the same spot on the ball is struck and the cue is pointing down the same line at the moment of contact, then the cueball will not "know" how it was struck imo. You will get the same reaction.

However, since you never really know where you are going to hit the cueball with DBHE, it can often seem like you are getting more spin with that technique. I find that when I use a training ball and compare the actual contact points by chalk marks, that when this happens (more apparent spin), it is always because I simply swerved the cue more than I expected (and therefore hit further away from center).

Not because the lateral movement of the cue did something "special" to the ball at the last moment.

The main advantage to DBHE that I see (and btw, besides some of the Philipino players, Strickland uses this as well) is that you never have to overcome the brain's resistance to "aim so darn crooked" when using a high squirt cue that you do with a conventional stroke.

You never "see" the final cue line and just how much you had to compensate to make the ball with the sidespin!

But as far as creating "spin", and spin related effects (like swerve and squirt), I don't think it matters how you get it done, as long as you hit the same place on the ball.

Tony
-although even I agree that it can seem otherwise...

heater451
06-13-2003, 07:32 PM
Tony, I had replied to Fred last night, but I must've not hit the final "Continue" button (after previewing).

Since I don't want to remember/rewrite it all, let me leave it at this:

I decided that, the swerve amount would indeed be the same--and my question was wrong. I asked about changing swerve, but was thinking about how the CB vector should/would change (which a person would adjust for, but a mechanism could not).

Anyway, I also hit a few balls around earlier, and 'discovered' another style for the mix. It seems that sometimes I use "parallel" english, and sometimes I line up the cue centerball, and then open or close my bridge 'V' (I mostly use open bridge), to adjust for spin. My back hand moves some. I **tend** to stroke statically, but sometimes go "dynamic".

No real point here, but your answers coincide with what Fred's post made me think about.

BTW, I added a page to my Tripod site about english (http://heater451.tripod.com/english.htm) , but I've still got work to do. (BTW, if you ever see anything that is incorrect, please send me a PM, or email me--this goes for anyone who reads this. Also, I reserve the right to argue about what's "incorrect". /ccboard/images/graemlins/cool.gif)



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