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littleCajun
03-03-2005, 09:26 AM
I have heard alot about spin induced throw. Right hand english will throw the ball right. Left hand english will spin the ball left.

The issue is with the shot posted below. If I can throw a ball with english. How do I pocket the 1 ball with spin and keep my cue ball on the line. I can not seem to do this?

Maybee doctor dave can help.

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Thanks

MrLucky
03-03-2005, 09:29 AM
<blockquote><font class="small">Quote littleCajun:</font><hr> I have heard alot about spin induced throw. Right hand english will throw the ball right. Left hand english will spin the ball left.<font color="red">I am assuming you are speaking of throwing the CUE since the object ball is thrown to the opposite of the cues spin? </font color>

The issue is with the shot posted below. If I can throw a ball with english. How do I pocket the 1 ball with spin and keep my cue ball on the line. I can not seem to do this?

Maybee doctor dave can help.

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Thanks <hr /></blockquote> /ccboard/images/graemlins/confused.gif

MrLucky
03-03-2005, 09:42 AM
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I hope this works LOL! look at this! <font color="purple"> The english you showed would IMO! ;-) throw the object ball to the rail in the opposite direction than that desired! </font color> /ccboard/images/graemlins/grin.gif

SplinterHands
03-03-2005, 09:50 AM
Hey Cajun,
You've got it backwards. You would need left hand english to throw it right. Maybe you could bank it from here or play position to shoot it straight in.

MrLucky
03-03-2005, 09:56 AM
<blockquote><font class="small">Quote MrLucky:</font><hr> START(
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I hope this works LOL! look at this! <font color="purple"> The english you showed would IMO! ;-) throw the object ball to the rail in the opposite direction than that desired! </font color> /ccboard/images/graemlins/grin.gif <hr /></blockquote> <font color="red">This RSB position would give yopu your desired result! </font color> /ccboard/images/graemlins/grin.gif

dr_dave
03-03-2005, 10:22 AM
<blockquote><font class="small">Quote littleCajun:</font><hr>The issue is with the shot posted below. If I can throw a ball with english. How do I pocket the 1 ball with spin and keep my cue ball on the line. I can not seem to do this?

Maybee doctor dave can help.

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As pointed out by others, you have the English backwards in your diagram. Left English will throw the object ball to the right and right English will throw the object ball to the left. Although, for the shot you show, I don't think it is possible to keep the cue ball close to online without hitting a bank shot.

For more information on spin-induced throw, see the links under "throw" at the Discussion Threads (http://www.engr.colostate.edu/~dga/pool/threads.html) section of my website. NV 4.15 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV4-15.htm) shows an example shot. I plan to re-shoot this video soon, because the cue ball is not hitting the object ball perfectly squarely; but even if it did, the cue ball would still drift to the right a little. If the object ball gets thrown in one direction, the cue ball will get "thrown" back in the opposite direction.

Regards,
Dr. Dave

Bob_Jewett
03-03-2005, 10:53 AM
<blockquote><font class="small">Quote littleCajun:</font><hr> ...
The issue is with the shot posted below. If I can throw a ball with english. How do I pocket the 1 ball with spin and keep my cue ball on the line. I can not seem to do this? ...<hr /></blockquote>
There is a test shot at http://www.sfbilliards.com/throwtest.gif that will tell you how much you can get an object ball to move off line and keep the cue ball on that line. I think you will find that it's easy to do if the cue ball and object ball are only an inch apart and very, very difficult to do when the balls are two feet apart.

In the test shot shown, the rail is used to very carefully get a straight line. Whether the object ball (OB) moves towards the cushion is shown by whether it hits the gauge ball (GB). Whether the cue ball moves towards the cushion (or stays on line) you can tell after the shot by seeing whether the cue ball is a ball or less away from the cushion.

The point of the shot is to see how far you can move the CB-OB apart and still meet the requirement that both balls move at least a little towards the cushion.

Here's a hint for experimenters who are having trouble: If one of the balls is going to the left and one to the right for a particular test distance, you need to change your aiming line. While this seems obvious on paper, on the table this idea escapes even some fairly good players.

Billy_Bob
03-03-2005, 11:46 AM
I've been practicing throw shots from the book 99 critical shots. It seems to me that the effect of throw is a slight deviation from the normal ball path.

What this means is that the further away from the pocket the object ball is, the more the deviation caused by throw can be noticed.

I would experiment with the following setup. Try left, right, left draw, right draw, and different speeds of hit. Then notice where the object ball hits the rail. You will learn what can and can't be done with this shot.

http://endeavor.med.nyu.edu/~wei/pool/

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littleCajun
03-03-2005, 12:54 PM
Thanks for everyones help;

Here is a follow up question then for Dr. Dave.

In the following setup, I can hit my cue with extreme right hand or left hand english and pocket the object ball in the side. and leave my cue ball like a stop shot sitting there spinning. Why does the object ball not throw to one side of the pocket or other.
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Thanks again for everyones input

BoroNut
03-03-2005, 01:21 PM
Potting with side makes the shot more difficult. I would bet good money that you are just cuing it wrong. Most inexperienced players simply move the tip around on the cue ball to strike the side they need. This means they are cuing slightly across the line instead of along it. Over short distances especially on a pool table you can often get away with it because of the large margin of error on the pots. You must move the whole cue over parallel to the potting line, as well as compensate for any expected deviation in it's path to the object ball.

dr_dave
03-03-2005, 01:37 PM
<blockquote><font class="small">Quote littleCajun:</font><hr>In the following setup, I can hit my cue with extreme right hand or left hand english and pocket the object ball in the side. and leave my cue ball like a stop shot sitting there spinning. Why does the object ball not throw to one side of the pocket or other.
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To stop the cue ball using side English, there must be a cut angle. In other words, the cue ball must hit the object ball slightly off center as if you were going to "cheat" the pocket (e.g., see NV 5.7 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV5-7.htm)). If you are aiming the shot straight-on, cue ball deflection (squirt) will automatically create the cut angle (see NV 4.13 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV4-13.htm) for a description and illustration of squirt). With a cut angle, if there was no English the object ball would cheat the pocket and the cue ball would drift along the tangent line. With left English, squirt causes the cue ball to deflect to the right, creating a cut angle to the left. However, the object ball would be thrown back to the right (due to the left English) towards the center of the pocket. Because the cue ball throws the object ball right, the object ball pushes back on the cue ball to the left, counteracting the expected tangent line motion to the right. Therefore, the cue ball stops in place. My recently posted May '05 instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/may05.pdf) doesn't answer your questions directly, but the information is relevant. Check it out if you are interested.

Dr. Dave

littleCajun
03-03-2005, 03:09 PM
All of your comments have been gratfully appritiated.

I have another question. I am just trying to understand the physics of how the balls react using spin.

So If,
"Because the cue ball throws the object ball right, the object ball pushes back on the cue ball to the left, counteracting the expected tangent line motion to the right."

The object ball pushes back on the cue ball, Would it be reasonable to say the same thing would happen with top and bottom spin.

So My Next Question: By this theroy I could use top spin at the right speed and have the cue ball come backwards if the center of the object ball and the cue ball are in line?

Thanks again for all the insight.

MrLucky
03-03-2005, 03:15 PM
<blockquote><font class="small">Quote littleCajun:</font><hr> All of your comments have been gratfully appritiated.

I have another question. I am just trying to understand the physics of how the balls react using spin.

So If,
"Because the cue ball throws the object ball right, the object ball pushes back on the cue ball to the left, counteracting the expected tangent line motion to the right."

The object ball pushes back on the cue ball, Would it be reasonable to say the same thing would happen with top and bottom spin.

So My Next Question: By this theroy I could use top spin at the right speed and have the cue ball come backwards if the center of the object ball and the cue ball are in line?

Thanks again for all the insight. <hr /></blockquote> <font color="red"> I seriously believe if you read Bob Jewitts article on the Jacksonville Experiment it will answer all or 99% of these questions..... </font color> <font color="purple"><blockquote><font class="small">Quote Bob_Jewett:</font><hr> I have bundled three BD articles about the Jacksonville Project into a PDF on the SFBA website: http://www.sfbilliards.com/jax_bd150.pdf

Included there is a speed/time analysis of a typical shot which shows the nearly instantaneous slowing of the stick at impact and the subsequent partial recovery of stick speed. <hr /></blockquote> </font color> /ccboard/images/graemlins/grin.gif

dr_dave
03-03-2005, 03:46 PM
<blockquote><font class="small">Quote littleCajun:</font><hr> All of your comments have been gratfully appritiated.<hr /></blockquote>
You are very welcome. I am happy to contribute to (and learn from) this great forum.

<blockquote><font class="small">Quote littleCajun:</font><hr>The object ball pushes back on the cue ball, Would it be reasonable to say the same thing would happen with top and bottom spin.<hr /></blockquote>
Yes. One observable result of the "throwing" friction force generated during impact is English transfer. With a draw shot, the cue ball transfers a little top spin to the object ball. With a follow shot, the cue ball transfers a little bottom spin to the object ball. In both cases, the cue ball's spin is reduced slightly by the impact, due to the equal and opposite friction force acting on the cue ball (from the object ball). HSV 4.6 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/HSV4-6.htm) and HSV A.66 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-66.htm) show how the ("throwing") friction force, in addition to creating throw effects, creates English transfer. These effects happen with any shots where there is relative motion between the cue ball and object ball at impact (side English, follow, draw, and even simple cut shots with no English [e.g., see HSV 4.9 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/HSV4-9.htm)]). I will shoot some high-speed clips in the future showing the English transfer effects for follow and draw shots. I don't have any available now.

<blockquote><font class="small">Quote littleCajun:</font><hr>So My Next Question: By this theroy I could use top spin at the right speed and have the cue ball come backwards if the center of the object ball and the cue ball are in line?<hr /></blockquote>No. The "throwing" friction force on the cue ball from follow would be straight up. The friction force does not push the cue ball back. It also cannot reverse the direction of the cue ball spin (e.g., converting follow to draw).

Bob_Jewett
03-03-2005, 04:17 PM
<blockquote><font class="small">Quote dr_dave:</font><hr>... With a draw shot, the cue ball transfers a little top spin to the object ball. With a follow shot, the cue ball transfers a little bottom spin to the object ball. In both cases, the cue ball's spin is reduced slightly by the impact, due to the equal and opposite friction force acting on the cue ball (from the object ball). ...

These effects happen with any shots where there is relative motion between the cue ball and object ball at impact (side English, follow, draw, and even simple cut shots with no English ... <hr /></blockquote>
One thing to note is that for a draw shot, the object ball leaves the table. The angle relative to the surface of the table is the same as for the angle of throw, which can be up to four degrees. This is the theory; I don't think anyone has actually observed this. One problem is that the cue ball must be on the cloth at impact, which it often isn't for hard shots, and on soft shots, the object ball will not leave the cloth by much. At the same time, the cue ball is expected to be driven into the cloth and maybe have some rebound.

For follow shots, the object ball is driven into the cloth and the cue ball is expected to jump up a little, but again it is hard to ensure that the cue ball is on the cloth at impact. On nearly every shot, the cue ball leaves the cloth at the start of the shot.

A small nit on the last-quoted sentence above: That should be "relative motions of the surfaces at the point of contact." An important case is when a shot is played with a lot of outside english (right for a cut to the left) where although the cue ball is moving in one direction, its surface at the contact point is moving in the opposite direction relative to the object ball's surface. When thought about as relative surface motion, it's clearer why draw and follow on the cue ball will reduce the effect of throw.

Chris Cass
03-03-2005, 04:18 PM
Hi LittleCajun,

I don't know if I can be of help or not but I think your looking for alot of movement by the throw shot. Truth is it's very little but is needed in many situations for a good hit. Atleast for me it is. Especially in tight games where the hit has to be clean and it requires the knowledge and skill to do it.

My example would be this,

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http://endeavor.med.nyu.edu/~wei/pool/pooltable2.html

The 5 ball is covering much of the 1 ball. So the hit head on, would catch a piece of the 5, if hit straight on. By hitting the cb with low right english. You almost stop the cb and you'll see the twist and go in clean.

Regards,

C.C.~~comes in handy sometimes. /ccboard/images/graemlins/grin.gif

Popcorn
03-03-2005, 04:20 PM
Have you done this shot on high speed ? If you shoot it with draw the front ball goes in and the second ball (8 ball) will follow it in. If you shoot it with follow, the front ball goes in, but no matter how hard you shoot the second ball (8 ball) will not go in even backing up a little

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dr_dave
03-03-2005, 04:24 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr>A small nit on the last-quoted sentence above: That should be "relative motions of the surfaces at the point of contact." An important case is when a shot is played with a lot of outside english (right for a cut to the left) where although the cue ball is moving in one direction, its surface at the contact point is moving in the opposite direction relative to the object ball's surface.<hr /></blockquote>
Bob,

Your point is well taken. In fact, I present the math and physics of this in TP A.7 (http://www.engr.colostate.edu/~dga/pool/technical_proofs/new/TP_A-7.pdf). I also describe and illustrate the results in my May '05 instructional article (http://www.engr.colostate.edu/~dga/pool/bd_articles/may05.pdf).

Regards,
Dave

dr_dave
03-03-2005, 04:41 PM
<blockquote><font class="small">Quote Popcorn:</font><hr> Have you done this shot on high speed ? If you shoot it with draw the front ball goes in and the second ball (8 ball) will follow it in. If you shoot it with follow, the front ball goes in, but no matter how hard you shoot the second ball (8 ball) will not go in even backing up a little

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http://endeavor.med.nyu.edu/~wei/pool/pooltable2.html <hr /></blockquote>
I have not filmed this shot yet, but I just added it to my list. NV 4.7 (http://www.engr.colostate.edu/~dga/pool/normal_videos/NV4-7.htm) and HSV 4.2 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/HSV4-2.htm) show the effect of the follow-in, but I don't have anything showing the English transfer (draw on the cue ball creating topspin on the 8-ball).

That's a good example. I'm almost embarrassed that it is not on my website already. I do discuss it in Principle 4.6 of my book (page 93), but it is not yet illustrated with a video demonstration. Thank you for the idea.

Regards,
Dave

littleCajun
03-03-2005, 04:52 PM
I would like to thank everyone for their input, and thanks for pointing be towards Bob's link to the jacksonville experiments, I have heard about this for awhile and never had a link.

MrLucky
03-03-2005, 08:47 PM
<blockquote><font class="small">Quote littleCajun:</font><hr> I would like to thank everyone for their input, and thanks for pointing be towards Bob's link to the jacksonville experiments, I have heard about this for awhile and never had a link. <hr /></blockquote> <font color="red">You are most welcome! I have been studying his writings myself lately! </font color> /ccboard/images/graemlins/smile.gif

dr_dave
03-04-2005, 01:47 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr>One thing to note is that for a draw shot, the object ball leaves the table ....

For follow shots, the object ball is driven into the cloth and the cue ball is expected to jump up a little<hr /></blockquote>
For anyone interested, HSV A.3 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-3.htm) and HSV A.4 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-4.htm) show these effects fairly clearly with 9-ball break shots.

Bob_Jewett
03-04-2005, 03:56 PM
<blockquote><font class="small">Quote dr_dave:</font><hr> ...
For anyone interested, HSV A.3 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-3.htm) and HSV A.4 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-4.htm) show these effects fairly clearly with 9-ball break shots. <hr /></blockquote>
But for break shots, the cue ball is certainly in the air for most of its travel to the rack, including when it hits the 1 ball, and that will also cause the cue ball to jump at impact.

dr_dave
03-04-2005, 04:03 PM
<blockquote><font class="small">Quote Bob_Jewett:</font><hr> <blockquote><font class="small">Quote dr_dave:</font><hr> ...
For anyone interested, HSV A.3 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-3.htm) and HSV A.4 (http://www.engr.colostate.edu/~dga/pool/high_speed_videos/new/HSVA-4.htm) show these effects fairly clearly with 9-ball break shots. <hr /></blockquote>
But for break shots, the cue ball is certainly in the air for most of its travel to the rack, including when it hits the 1 ball, and that will also cause the cue ball to jump at impact. <hr /></blockquote>
Agreed. The videos still show the English transfer effects of the vertical friction force generated between the cue ball and 1-ball. As you have pointed out, this same force can cause both the cue ball and object ball to leave the table surface (for fast shots).