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cushioncrawler
01-21-2007, 12:12 AM
I would like to know how players might hit a qball to get the max of sidespin. Here i mean the max of spin/rolling ratio. Here the spin axis would be nearest to vertical (not that u would see it).

I reckon that a good way of finding or prooving the max is perhaps to hit the qball squarely towards a mark (A) on a side-cushion and then mark (B) where it hits the other cushion. The widest mark (B) would indicate the max spin ratio, i think.

The angle from A to B iznt very important on its own i think, koz this will vary from table to table, but the best way to hit the qball to achieve this max wont vary, i think. Any ideas??? madMac.

Stretch
01-21-2007, 08:50 AM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> I would like to know how players might hit a qball to get the max of sidespin. Here i mean the max of spin/rolling ratio. Here the spin axis would be nearest to vertical (not that u would see it).

I reckon that a good way of finding or prooving the max is perhaps to hit the qball squarely towards a mark (A) on a side-cushion and then mark (B) where it hits the other cushion. The widest mark (B) would indicate the max spin ratio, i think.

The angle from A to B iznt very important on its own i think, koz this will vary from table to table, but the best way to hit the qball to achieve this max wont vary, i think. Any ideas??? madMac. <hr /></blockquote>

Hi cush. that's a good test to shoot to the middle of the end rail and then observe where the cb spins into the siderail.

How i achieve max side spin is to hit low right, or low left. You play this shot like a draw drag. by hitting it hard you get max side spin. Because of the draw stroke though the cb will slow down before hitting the rail as the back spin wares off. The back spin wares off but the side spin does not. Most shots hit with max side are also hit hard so the angle off the first rail is limited to the speed at which it hits the rail. By combining spin with draw you magnify the effect of the side spin and resulting rebound angle and get "MAX" angle off the rail. St.

mworkman
01-21-2007, 09:16 AM
I think you can get more english with a straight 3:00 or 9:00 hit then you can with a low/left high/right etc.

Set up an object ball one ball width from the rail. Place cueball in a set position that you can repeat over and over. I believe your inside english will be maxed with just side only and you can get farther back with a combination of english and draw.

Duckie
01-21-2007, 10:30 AM
For me, I've found that stroke speed and follow through have the biggest affect on the english I can get on a ball.

cushioncrawler
01-21-2007, 02:39 PM
<blockquote><font class="small">Quote Stretch:</font><hr> ...Hi cush. that's a good test to shoot to the middle of the end rail and then observe where the cb spins into the siderail. How i achieve max side spin is to hit low right, or low left. You play this shot like a draw drag. by hitting it hard you get max side spin. Because of the draw stroke though the cb will slow down before hitting the rail as the back spin wares off. The back spin wares off but the side spin does not. Most shots hit with max side are also hit hard so the angle off the first rail is limited to the speed at which it hits the rail. By combining spin with draw you magnify the effect of the side spin and resulting rebound angle and get "MAX" angle off the rail. St. <hr /></blockquote> Stretch -- Actually u have gone straight to the heart of what i was really thinking. Books on English Billiards have lots of stuff about playing drag shots, they say that this is the best way to maximize the sidespin, especially if u want to play a long-distance slowish shot of some sort (uzually a cannon or in-off).

But, one day, i spent lots of time putting this sort of thing to the test, and i found that drag didnt work for me. I am more like mworkman, for me, hitting just below 3o'c (say 4o'c) and just below 9o'c (say 8o'c) worked better for me at all ranges and all paces.

Duckie sez that speed and follow throo work best. I uze a whippy cue, but to get max i allways uze a flourish to help (and a long follow-throo), this is probably just an old habit from the days when i uzed stiff cues. But i know that i can get some pretty good sidespin with zero follow throo too, just uzing a sharp poke, a jab, but i karnt remember ever testing this jab for this sort of banking-test.

I have seen some players checking something (dont know what) on a 12' table, doing what u (Stretch) mention, ie hitting up the centerline with max spin, and seeing where the qball hit the side cushion. On a 12' table, hitting before the middle pocket is good, and it is difficult to do much better than that.

A definite legitimate shot in English billiards is when u are in hand, and double-baulked. Here the standard shot is to place the qball on the baulk-line and shoot along the baulk-line hitting the cushion just out of baulk (like the rule requires) with enuff sidespin to get the angle to get the shot. If the red is sitting in the lips of the pocket baulk-pocket, it takes more sidespin than one might think to get the angle to hit the red and get the pot (or to at least spoil the opponents pozzy). For these sorts of baulk-shots, i do best by hitting a bit below the equator, but i dont get any profit by uzing a very lowish contact (ie drag), in fact i seem to looz a bit of angle uzing drag. But, perhaps its an individual thing, which is why i am asking.

Another thing, getting the max is one thing, but i suppose that what sort of contact or style gives u best judgement of the angle is probably even more important.

For example, Willie Smith, in hiz books, sez that for the baulk-shot that i mentioned earlyr, Willie allways uzes the max of sidespin, whether he needs it or not. What Willie did is that he hit the side-cushion close to the baulk-line or somewhat further away, but he allways used the max of sidespin. This gave him better judgement. Now, i allways do it myself, in a serious match (i think that i am the only player in the world that seems to make the shot more difficult like this). I suppoze that in pool this sort of bank shot comes up a lot, when another ball is blocking a direct bank-shot, but i wonder if uzing the max of english is any good for judgement (for pool and pool cushions), ie uzing it even tho u dont havta. Perhaps you'all might try this az well and tell'us what u think. madMac.

dr_dave
01-21-2007, 04:40 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> I would like to know how players might hit a qball to get the max of sidespin. Here i mean the max of spin/rolling ratio. Here the spin axis would be nearest to vertical (not that u would see it).<hr /></blockquote>
To get maximum English,

short answer: prepare and chalk a good tip, and hit the cue ball as far left or right of center as you can without miscuing.

long answer: see my October '05 instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/2005/oct05.pdf).

Now, to achieve the most effect from the sidespin (i.e., get the most rebound angle change off a rail), as others have pointed out, you want to use a drag shot where you hit enough below center to create stun at rail contact. The problem with hitting below center is that you have to decrease the amount of sidespin a little. For a slick cloth and/or short distance to rail, and/or faster stroke, where you don't need to sacrifice as much sidespin to achieve stun, the effect can be significant.

Regards,
Dave

Stretch
01-21-2007, 05:06 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> <blockquote><font class="small">Quote cushioncrawler:</font><hr> I would like to know how players might hit a qball to get the max of sidespin. Here i mean the max of spin/rolling ratio. Here the spin axis would be nearest to vertical (not that u would see it).<hr /></blockquote>
To get maximum English,

short answer: prepare and chalk a good tip, and hit the cue ball as far left or right of center as you can without miscuing.

long answer: see my October '05 instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/2005/oct05.pdf).

Now, to achieve the most effect from the sidespin (i.e., get the most rebound angle change off a rail), as others have pointed out, you want to use a drag shot where you hit enough below center to create stun at rail contact. The problem with hitting below center is that you have to decrease the amount of sidespin a little. For a slick cloth and/or short distance to rail, and/or faster stroke, where you don't need to sacrifice as much sidespin to achieve stun, the effect can be significant.

Regards,
Dave <hr /></blockquote>

Dave , the other thing worth considering is while max side spin can be achieved with extreme side on the cb this will always be accompanied with max squirt which makes them very tuff to aim up and exicute over distance. For all practical purposes i think you have to balance your ability to impart max spin against the likelyhood you'll actually make the shot. So with this in mind i usually opt for a low left (or right) drag shot for distance shooting where i need max spin. Like you say, I'm sacrificing a little spin because the tip placement is a little closer to the vertical axis, but it's easier to aim and control while still getting me great action off the first rail. Now when i'm close to the object ball, or it's close to the pocket where there's quite a large margin for error i'll venture more to the extreme side as a way of getting the max spin. Which one is better? why the one that makes the ball and gets your shape of course! St.

cushioncrawler
01-21-2007, 05:21 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> ....To get maximum English, short answer: prepare and chalk a good tip, and hit the cue ball as far left or right of center as you can without miscuing..... Now, to achieve the most effect from the sidespin (i.e., get the most rebound angle change off a rail), as others have pointed out, you want to use a drag shot where you hit enough below center to create stun at rail contact. The problem with hitting below center is that you have to decrease the amount of sidespin a little. For a slick cloth and/or short distance to rail, and/or faster stroke, where you don't need to sacrifice as much sidespin to achieve stun, the effect can be significant. Regards, Dave <hr /></blockquote> Hi Dr Dave -- I think that there is something wrong with Coriolis' stuff (as quoted in your above article) in theory and in praktis. I believe that hitting a bit below the equator duznt looz much sidespin, but eliminates a fair amount of topspin. So Byrnes' and Bob's and Shepard's (and your) spin/roll ratio should then be more (in fact i believe it would be a max).

But i dont believe that lots of drag is good (but it seems to work for Stretch). And, i dont agree with Shepard's article where he i think proposes that lots of drag gives a good rezult (but i karnt really understand Ron's equations and logic and explanation, but i disagree anyhow). This was the main reason behind this thread, to see if anyone is fond of lots of drag, or whether someone out there is like me and likes a little bit of drag, or like yourself and mworkman who are fond of 3 o'c and 9 o'c.

I am surprized re your proposal that stun (at cushion impact) would maximize the angle of the qball's sidespin off the cushion. I would rush out and try it, but my 12' table is now in storage in my loft, and my 6' table is on the other side of Port Phillip. Perhaps someone else can try it and report back. Perhaps the high pool-style cushions do something peculiar here, some sort of trappy effect, Hmmmmmm. Stretch advocates lots of drag, but he didnt mention "stunny" pace. madMac.

cushioncrawler
01-21-2007, 05:31 PM
<blockquote><font class="small">Quote Stretch:</font><hr> .... Now when i'm close to the object ball, or it's close to the pocket where there's quite a large margin for error i'll venture more to the extreme side as a way of getting the max spin. Which one is better? why the one that makes the ball and gets your shape of course! St.<hr /></blockquote> But, dont forget, that when u have the luxury of coming off an object-ball, then here stunning the qball into the object-ball would maximize the qball's spin/rolling ratio (if this helps the shot). But this is a different thing to Dr Dave's proposal re stunning the qball off the cushion. madMac.

Stretch
01-21-2007, 07:58 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> <blockquote><font class="small">Quote Stretch:</font><hr> .... Now when i'm close to the object ball, or it's close to the pocket where there's quite a large margin for error i'll venture more to the extreme side as a way of getting the max spin. Which one is better? why the one that makes the ball and gets your shape of course! St.<hr /></blockquote>

But, dont forget, that when u have the luxury of coming off an object-ball, then here stunning the qball into the object-ball would maximize the qball's spin/rolling ratio (if this helps the shot). But this is a different thing to Dr Dave's proposal re stunning the qball off the cushion. madMac. <hr /></blockquote>

Not really. The collision with the ob takes the pace off the cb and thus helps the spin roll ratios in the ball first scenario. While the draw drag takes the pace off the cb in the rail first scenario. In both cases you are able to enhance the action off the first rail by slowing the cb down enough for the spin to "take". St.

Jal
01-21-2007, 10:45 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> Hi Dr Dave -- I think that there is something wrong with Coriolis' stuff (as quoted in your above article) in theory and in praktis. I believe that hitting a bit below the equator duznt looz much sidespin, but eliminates a fair amount of topspin. So Byrnes' and Bob's and Shepard's (and your) spin/roll ratio should then be more (in fact i believe it would be a max).

But i dont believe that lots of drag is good (but it seems to work for Stretch). And, i dont agree with Shepard's article where he i think proposes that lots of drag gives a good rezult (but i karnt really understand Ron's equations and logic and explanation, but i disagree anyhow). This was the main reason behind this thread, to see if anyone is fond of lots of drag, or whether someone out there is like me and likes a little bit of drag, or like yourself and mworkman who are fond of 3 o'c and 9 o'c.<hr /></blockquote>Mac, the simple physics answer is to hit at the intersection of the dotted circles below:

http://ww2.netnitco.net/users/gtech/Maxrwv.jpg

This yields the greatest sidespin/speed ratio when the cueball reaches either stun or natural roll. (Ron Shepard derives this for at least the case of natural roll, but I can't remember if he includes stun. At any rate, it applies to stun as well, and probably to any amount of topspin in-between.)

To be more specific, any point along the green circle produces the largest ratio for that amount of tip offset. As you move along the circle away from centerball, the ratio increases. Where the two dotted circles intersect, you get the largest ratio of all, practically speaking, since this is at the miscue limit of (1/2)R. The point is located at (1/4)R below center and (1/4)Sqrt(3)R (=0.43R) to the side.

It's 'simple' physics in that the derivation assumes no loss of sidespin on the way to stun or natural roll, and a level cue. To adjust for sidespin loss, common sense says that you would have to move each point up (less drag) and/or to the side (more sidespin) a little.

Simply put, to get the greatest ratio, go out as close as you dare to (1/2)R from center, and such that contact is made slightly less than (1/4)R below center. This point lies on a line from the center of the cueball to the base of a ball frozen to it on the side the english is applied (approximately).

Jim

cushioncrawler
01-21-2007, 11:58 PM
Jim -- So, the intersection (the max) is at say 7:30 o'c, or, allowing for spin friction loss, the max would be very close to my 8 o'c. This sounds ok to me. But, some feedback regarding actual banking tests are needed. Is Dr Dave's stun-spin a winner???

Jal
01-22-2007, 12:40 AM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> Jim -- So, the intersection (the max) is at say 7:30 o'c, or, allowing for spin friction loss, the max would be very close to my 8 o'c.<hr /></blockquote>Mac, I was derelict in not noting that your figures of 4:00 and 8:00 (doesn't matter if A.M or P.M) was exactly what the simple physics predicts. As a billiards experimentalist, you are quite possibly unsurpassed. Bravo! The angle of the line to the contact point at offset (1/2)R is exactly 30 degrees from horizontal.

I haven't worked it out for sidespin loss or cue elevation, since it's unlikely to generate anything as simple as the circle, and probably (apparently!) doesn't change things much (not to mention laziness on my part).

<blockquote><font class="small">Quote cushioncrawler:</font><hr>...But, some feedback regarding actual banking tests are needed. Is Dr Dave's stun-spin a winner??? <hr /></blockquote>I'm not sure what you mean?

Jim

dr_dave
01-22-2007, 09:48 AM
<blockquote><font class="small">Quote cushioncrawler:</font><hr>I am surprized re your proposal that stun (at cushion impact) would maximize the angle of the qball's sidespin off the cushion.<hr /></blockquote>I also hope to measure this stuff accurately in the future. The drag shot creates two effects. It slows the CB's translational speed, making the spin more effective, and the stun optimizes the direction of the sidespin friction force. Again, I agree further study is in order.

Dave

Deeman3
01-22-2007, 12:01 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> Jim -- So, the intersection (the max) is at say 7:30 o'c, or, allowing for spin friction loss, the max would be very close to my 8 o'c. This sounds ok to me. But, some feedback regarding actual banking tests are needed. Is Dr Dave's stun-spin a winner??? <hr /></blockquote>

<font color="blue">I wuz gonna tryout thiz but only have a digital clok, not an analog..... </font color>

DeeMan

1hit1der
01-22-2007, 12:11 PM
So does stroke speed only matter depending on how far away you want the spin/roll ratio to be maximum? Also, does stroke acceleration matter at the time of impact?

Ace
01-22-2007, 01:04 PM
<blockquote><font class="small">Quote Deeman3:</font><hr> <blockquote><font class="small">Quote cushioncrawler:</font><hr> Jim -- So, the intersection (the max) is at say 7:30 o'c, or, allowing for spin friction loss, the max would be very close to my 8 o'c. This sounds ok to me. But, some feedback regarding actual banking tests are needed. Is Dr Dave's stun-spin a winner??? <hr /></blockquote>

<font color="blue">I wuz gonna tryout thiz but only have a digital clok, not an analog..... </font color>

DeeMan <hr /></blockquote>


Digital Clocks?
Oh, So that's what has been wrong with my game. I have to get another clock! There goes all that time I spent practicing.

dr_dave
01-22-2007, 01:11 PM
<blockquote><font class="small">Quote 1hit1der:</font><hr>So does stroke speed only matter depending on how far away you want the spin/roll ratio to be maximum?<hr /></blockquote>Yes.

<blockquote><font class="small">Quote 1hit1der:</font><hr>Also, does stroke acceleration matter at the time of impact?<hr /></blockquote>short answer: absolutely not
long answer: it might have a tiny (insignificant) effect.

However, acceleration might help indirectly by helping you create a smoother stroke. If you accelerate smoothly from the back-swing pause all of the way through tip contact, you might generate better speed without being jerky and inconsistent. See my stroke "best practices" summary (http://www.engr.colostate.edu/~dga/pool/resources/stroke_best_practices.pdf) for more info.

Regards,
Dave

Scott Lee
01-22-2007, 01:46 PM
<blockquote><font class="small">Quote mworkman:</font><hr> I think you can get more english with a straight 3:00 or 9:00 hit then you can with a low/left high/right etc.

Set up an object ball one ball width from the rail. Place cueball in a set position that you can repeat over and over. I believe your inside english will be maxed with just side only and you can get farther back with a combination of english and draw. <hr /></blockquote>

You're comparing apples to oranges. Hitting high or low, with sidespin, adds another variable to the observable effect on the CB. Top and bottom cause the CB to curve. Straight sidespin (3:00 or 9:00) does not, until contact with a rail.

Scott Lee

Bob_Jewett
01-22-2007, 02:48 PM
<blockquote><font class="small">Quote Scott Lee:</font><hr> ... You're comparing apples to oranges. Hitting high or low, with sidespin, adds another variable to the observable effect on the CB. Top and bottom cause the CB to curve. Straight sidespin (3:00 or 9:00) does not, until contact with a rail. ... <hr /></blockquote>
In my experience, this is false. Because pretty much every shot is played with an elevated stick, pretty much every shot with side spin will curve towards the side of the english. If in fact a 3:00 shot got no curve, then a follow shot would be expected to curve away from the side of the english. Instead it curves towards the side of the english.

cushioncrawler
01-22-2007, 03:02 PM
<blockquote><font class="small">Quote Stretch:</font><hr>....Dave , the other thing worth considering is while max side spin can be achieved with extreme side on the cb this will always be accompanied with max squirt which makes them very tuff to aim up and exicute over distance. For all practical purposes i think you have to balance your ability to impart max spin against the likelyhood you'll actually make the shot. So with this in mind i usually opt for a low left (or right) drag shot for distance shooting where i need max spin. Like you say, I'm sacrificing a little spin because the tip placement is a little closer to the vertical axis, but it's easier to aim and control while still getting me great action off the first rail. Now when i'm close to the object ball, or it's close to the pocket where there's quite a large margin for error i'll venture more to the extreme side as a way of getting the max spin. Which one is better? why the one that makes the ball and gets your shape of course! St. <hr /></blockquote> Stretch -- I agree with u that deep drag (plus spin) is good for accuracy at long range, even tho (for me) it duznt give max spin/roll ratio. Hitting close to the equator duz give the qball more time to swerve or run-off.

In English billiards the drag shot was universal for long slow shots, koz otherwize the ivory balls might roll-off, or koz the tables werent all level. But, the oldbooks then all went one step further and said that likewize deep drag was best for slow long-range sidespin allso (12' tables here) -- and i am happy to go along with that too (ie i agree with what u said above). But then the old books go one step further and claim that deep drag makes sidespin "tell" better at long range -- my drag tests show this to be false, at least for me (but as u say it works for u).

Actually, perhaps i did do some rebound tests for deep drag, ie hitting up the centerline like mentioned earlier. Yes, i think that this prooved to me that 8 o'c was better than 7 o'c. But this was for flat cushions, which is one reason that i asked what happens on high and sharp-nosed pool cushions. madMac.

cushioncrawler
01-22-2007, 03:11 PM
<blockquote><font class="small">Quote mworkman:</font><hr> I think you can get more english with a straight 3:00 or 9:00 hit then you can with a low/left high/right etc. Set up an object ball one ball width from the rail. Place cueball in a set position that you can repeat over and over. I believe your inside english will be maxed with just side only and you can get farther back with a combination of english and draw. <hr /></blockquote> Ah, i see what u mean now -- u are talking about potting a ball with outside english and then the qball coming back to u off one cushion. Yes, here there wouldnt be a lot of difference between contacting the qball on the equator or at 8 o'c or deeper, especially for a thickish contact on the objectball -- alltho Dr Dave's stunny-spin might have some effect here. Actually, i have changed my mind, i think that Stretch's deep drag might win here, if u hit it real hard so that the qball has some screw left when it reaches the OB, the screw should more than make up for any loss of sidespin, but i dont know much about pool balls and pool cushions and pool tables. madMac.

cushioncrawler
01-22-2007, 03:32 PM
<blockquote><font class="small">Quote Jal:</font><hr> <blockquote><font class="small">Quote cushioncrawler:</font><hr>...But, some feedback regarding actual banking tests are needed. Is Dr Dave's stun-spin a winner??? <hr /></blockquote>I'm not sure what you mean? Jim <hr /></blockquote> Off hand, i would say that any stun or screw would hurt the rebound angle not increase it. For instance, hitting the qball into a cushion at say 10dg off square, with screw, u shood be able to get the qball to come back to where it started, without using any english at all. I wonder what the limiting angle is for this sort of screw shot. I play into the cushion with screw when the angle of attack to the cushion is say 45dg or less, koz inside english (what i call check-side) has either zero effect, or more often, it has the same sort of effect as outside english, ie it hurts the rebound angle. When the angle to the cushion is 45dg or less, i use zero spin, and 100% screw, and i get a nice squarer rebound. Karnt see why this "trick" shoodnt allso work for K55's (or whatever).

This effect is why i reckon that Dr Dave's proposal for using stunny-spin must be counterproductive. But, perhaps the stun allows the qball to sink under the cushion, and be sort of trapped, and the "e" for the cushion rebound might drop from 0.73 (or whatever) to say 0.60 (or whatever) and thusly increase the angle anyhow. But tests would soon show. madMac.

Bob_Jewett
01-22-2007, 03:59 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr> ... Off hand, i would say that any stun or screw would hurt the rebound angle not increase it. ... <hr /></blockquote>
Here is a simple test. Shooting from a corner pocket to the opposite end cushion, try to bring the cue ball off the end cushion back to that same corner pocket. See how far out on the cushion you can take the cue ball and sitll bring it back to the corner. Try side with follow, center and draw. See which one allows you to shoot farthest out and still come straight back along the line you go out on.

Having tried this shot many times, I suspect I know what your result will be, but I await your response. 6x12 tables are different from pool tables. For example, shooting a bank hard on snooker cushions causes the ball to bank longer.

cushioncrawler
01-22-2007, 04:45 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote cushioncrawler:</font><hr> ... Off hand, i would say that any stun or screw would hurt the rebound angle not increase it. ... <hr /></blockquote> Here is a simple test. Shooting from a corner pocket to the opposite end cushion, try to bring the cue ball off the end cushion back to that same corner pocket. See how far out on the cushion you can take the cue ball and sitll bring it back to the corner. Try side with follow, center and draw. See which one allows you to shoot farthest out and still come straight back along the line you go out on. Having tried this shot many times, I suspect I know what your result will be, but I await your response. 6x12 tables are different from pool tables. For example, shooting a bank hard on snooker cushions causes the ball to bank longer. <hr /></blockquote> Hi Bob -- I suspect that the answer is that screw wins over simple sidespin (rolling) -- but i doubt that anyone can get any screw on a 12' table, ie at a range of 10'. I would try this off a side cushion, ie a range of less than 5'. But i probably wont get a chance for a while, it is the snooker season and i wont be playing billiards till July, but i might do some tests on my 6' table the next time i go to my mountain home, might be a week or two, so perhaps u can spill the beans now.

Anyhow, the extra rebound angle that one gets with screw is the exact reason that i have doubts re Dr Dave's proposal that stun helps the rebound angle in our 90dg tests, koz here that effect can only hurt the rezult (it appears to me).

Funny thing, with bare rubber cushions, one can hit the qball at 45dg to the cushion, and inside english can bring the qball back on that same 45dg line, and one can even do a few degrees better than this. Looks funny. Havent tryd this with screw.

Bob -- What about my earlyr statement that inside english hurts the rebound angle when the attack angle is 45dg or less. This applys to 12' cushions, duz it apply to pool cushions???

dr_dave
01-22-2007, 05:15 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr>i have doubts re Dr Dave's proposal that stun helps the rebound angle<hr /></blockquote>I just want to be clear that I have not verified this claim with experiments or theory yet. I just claimed that it seemed to make intuitive sense.

Dave

Jal
01-22-2007, 05:49 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>...<blockquote><font class="small">Quote 1hit1der:</font><hr>Also, does stroke acceleration matter at the time of impact?<hr /></blockquote>short answer: absolutely not
long answer: it might have a tiny (insignificant) effect.<hr /></blockquote>Dr. Dave,

Correct me if I'm wrong, but I think you're saying that continuing to apply force during impact results in very little gain (a few percentage points maybe). For what it's worth, I agree.

But I believe that it's probably not too difficult to see something like a 10-15% increase in cue/cueball speed if you "stretch" your stroke out so that you're accelerating at impact (due to a difference in shape of the force vs time curve up until impact). I think you might be saying as much in the next paragraph:

<blockquote><font class="small">Quote dr_dave:</font><hr>However, acceleration might help indirectly by helping you create a smoother stroke. If you accelerate smoothly from the back-swing pause all of the way through tip contact, you might generate better speed without being jerky and inconsistent. See my stroke "best practices" summary (http://www.engr.colostate.edu/~dga/pool/resources/stroke_best_practices.pdf) for more info.<hr /></blockquote>

I only bring it up because I think the two "accelerations" tend to be confused in many discussions.

Jim

Jal
01-22-2007, 06:25 PM
<blockquote><font class="small">Quote cushioncrawler:</font><hr>Off hand, i would say that any stun or screw would hurt the rebound angle not increase it. For instance, hitting the qball into a cushion at say 10dg off square, with screw, u shood be able to get the qball to come back to where it started, without using any english at all. I wonder what the limiting angle is for this sort of screw shot. I play into the cushion with screw when the angle of attack to the cushion is say 45dg or less, koz inside english (what i call check-side) has either zero effect, or more often, it has the same sort of effect as outside english, ie it hurts the rebound angle. When the angle to the cushion is 45dg or less, i use zero spin, and 100% screw, and i get a nice squarer rebound. Karnt see why this "trick" shoodnt allso work for K55's (or whatever).

This effect is why i reckon that Dr Dave's proposal for using stunny-spin must be counterproductive. But, perhaps the stun allows the qball to sink under the cushion, and be sort of trapped, and the "e" for the cushion rebound might drop from 0.73 (or whatever) to say 0.60 (or whatever) and thusly increase the angle anyhow. But tests would soon show. madMac. <hr /></blockquote>Mac, I think that if a ball has top or screw along with sidespin, it depends on whether or not all of the spin is rubbed off by the cushion. If it is, then the sidespin should exert its full influence, and the top or screw none. If the spin isn't rubbed off, then the sidespin should be thwarted to some extent, and the post-impact masse action from the residual top or screw should have something to say about the ball's final direction.

But I'm not sure what question we're trying to answer at this point. In the case of a perpendicular attack angle, some residual topspin might help to widen the rebound, since the side and top aren't removed at the same rate (the ball can't move up but it can move sideways). There might be an optimum ratio of top to side, to go along with the maximum ratio of sidespin to speed.

Jim

Scott Lee
01-22-2007, 07:49 PM
Once again Bob, we'll have to agree to disagree. Place an OB on the footspot. Put the CB a foot away, on a slight cut angle (say 15 degrees, so you won't miss the shot). Striking the CB with a level cue at 3 or 9 o'clock still produces a 90 degree tangent line from the collision, towards or into the side pocket...no curve, but plenty of sidespin on the CB.

Scott Lee

Bob_Jewett
01-22-2007, 09:30 PM
<blockquote><font class="small">Quote Scott Lee:</font><hr> Once again Bob, we'll have to agree to disagree. ... <hr /></blockquote>
Not a disagreement this time, just my misunderstanding of what was being discussed. Of course a cue ball with follow will curve ahead of the tangent line as it leaves the object ball and with draw it will curve back of the tangent line. I hope no one here disputes that. I got lost in the verbosity of this thread and failed to read all of the posts before responding. I was thinking about cue ball curve prior to hitting the object ball.

Rod
01-22-2007, 09:41 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote cushioncrawler:</font><hr> ... Off hand, i would say that any stun or screw would hurt the rebound angle not increase it. ... <hr /></blockquote>
Here is a simple test. Shooting from a corner pocket to the opposite end cushion, try to bring the cue ball off the end cushion back to that same corner pocket. See how far out on the cushion you can take the cue ball and sitll bring it back to the corner. Try side with follow, center and draw. See which one allows you to shoot farthest out and still come straight back along the line you go out on.

Having tried this shot many times, I suspect I know what your result will be, but I await your response. 6x12 tables are different from pool tables. For example, shooting a bank hard on snooker cushions causes the ball to bank longer.
<hr /></blockquote>

Bob, I've looked at this thread before, knew the answer but never replied. Your simple test will make it obvious real quick. Really I'm surprised at this discussion since it's not uncommon to have to hit a ball this way.

Rod

dr_dave
01-23-2007, 08:24 AM
<blockquote><font class="small">Quote Jal:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr>...<blockquote><font class="small">Quote 1hit1der:</font><hr>Also, does stroke acceleration matter at the time of impact?<hr /></blockquote>short answer: absolutely not
long answer: it might have a tiny (insignificant) effect.<hr /></blockquote>Dr. Dave,

Correct me if I'm wrong, but I think you're saying that continuing to apply force during impact results in very little gain (a few percentage points maybe). For what it's worth, I agree.<hr /></blockquote>
That's correct ... that's what I'm saying. Acceleration during tip contact (0.001 second or so) will have insignificant effect.

<blockquote><font class="small">Quote Jal:</font><hr>But I believe that it's probably not too difficult to see something like a 10-15% increase in cue/cueball speed if you "stretch" your stroke out so that you're accelerating at impact (due to a difference in shape of the force vs time curve up until impact). I think you might be saying as much in the next paragraph:

<blockquote><font class="small">Quote dr_dave:</font><hr>However, acceleration might help indirectly by helping you create a smoother stroke. If you accelerate smoothly from the back-swing pause all of the way through tip contact, you might generate better speed without being jerky and inconsistent. See my stroke "best practices" summary (http://www.engr.colostate.edu/~dga/pool/resources/stroke_best_practices.pdf) for more info.<hr /></blockquote>

I only bring it up because I think the two "accelerations" tend to be confused in many discussions.<hr /></blockquote>It sounds like we agree. Acceleration before and up to impact can be a good thing.

Regards,
Dave

Jal
01-23-2007, 11:41 AM
<blockquote><font class="small">Quote Jal:</font><hr>... the simple physics answer is to hit at the intersection of the dotted circles below:

http://ww2.netnitco.net/users/gtech/Maxrwv.jpg

...it applies to stun as well, and probably to any amount of topspin in-between.)<hr /></blockquote>It does apply to any amount of topspin in-between. In fact, it covers any "final" topspin or draw state from the initial one to roll, ie, topspin/speed ratios (RW/V) from -5/8 to 1.

Jim

Jal
01-23-2007, 02:48 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> <blockquote><font class="small">Quote Jal:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr>...<blockquote><font class="small">Quote 1hit1der:</font><hr>Also, does stroke acceleration matter at the time of impact?<hr /></blockquote>short answer: absolutely not
long answer: it might have a tiny (insignificant) effect.<hr /></blockquote>Dr. Dave,

Correct me if I'm wrong, but I think you're saying that continuing to apply force during impact results in very little gain (a few percentage points maybe). For what it's worth, I agree.<hr /></blockquote>
That's correct ... that's what I'm saying. Acceleration during tip contact (0.001 second or so) will have insignificant effect.<hr /></blockquote>Thanks for reminding me of that .001 second (or so). It makes even "a few percentage points" a gross overestimate!

Jim