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DBK
05-28-2011, 08:35 AM
Hi all.
I have long wanted to see what happens with cue when a cue shot. Videos, which is presented on the Internet does not fully reflect the process, but I have not my own opportunity to do such video:thumbup:. However, recently met a kindred spirit who could do it. That's what happened to date.
I tried to submit a video in English, do not judge strictly for errors in translation.

Here, my friend's article about a wave properties of the cue. (http://dbkcues.ru/2011/05/28/let-s-try-to-check-the-harmony-with-algebra-c-a-pushkin/?lang=en)

Direct link to the article (http://dbkcues.ru/articles-2/investigation-in-some-wave-properties-of-a-billiards-cue/?lang=en)

Here the video with English shot. (http://dbkcues.ru/2011/05/28/the-first-russian-experience-with-high-speed-video-hs-video/?lang=en)

Here the video with the Follow and Draw shot. (http://dbkcues.ru/2011/05/28/new-portion-of-the-hs-video-follow-and-draw-shot/?lang=en)

Here a video about the transfer rotation between the balls. (http://dbkcues.ru/2011/05/28/is-there-a-transmission-rotation-between-the-balls-hs-video/?lang=en)

A little later I will try to provide frame by frame transcript of videos to facilitate the timing analysis of processes.

I will appreciate your ideas. So I will be grateful if you enter the grammatical errors in the article and descriptions. If there are errors, please let me know by my e-mail address (DBKCues@gmail.com). Sorry for my English:blush:. Waiting for your opinion here on the forum or on my blog (http://dbkcues.ru/?lang=en) or by e-mail (DBKCues@gmail.com). Thank you.

Good luck,
Dmitry

LAMas
05-28-2011, 09:06 AM
Very informative.
I notice that the shaft moves away from the point of contact/impact.
Is that due to the mass of the tip or the flex in the shaft?
Or both?

What is happening with the miss cue?

Thanks.:thumbup:

duckie
05-28-2011, 09:09 AM
wow, thanks for links.

This may be a far reach, but how bout high speed of a person making these shots. Do from the top, back and both sides.

Maybe the same shots made by different people that use different stances and styles.

And this one I'd love to have done. A motion studying of different pool players. You know, one where you put a person in s suit to record how they do things.

Anyway, those were so cool, thanks again.

SUPERSTAR
05-28-2011, 09:22 AM
Disclaimer. This is NOT an attempt to knock the videos!!

From the video, it doesn't look like they are laying a very good stroke on the cueball.
Kind of looks like a poke stroke.

I might be way off, but it almost looks like they are bunting the ball with no follow through. Almost stopping after contact. With zero hang time for the tip on the cueball.

I only say this because of the speed at which the cueball leaves the tip, and the increasing distance between tip and cueball after the shot.
It seems like it's too much distance, too fast, especially for slow-mo.

Maybe that is a result of the slow-mo effect, but something just doesn't look right.

But either way, thank you for the videos.

pulzcul
05-28-2011, 11:09 AM
Here is a website put up by Dr. Dave that covers your subject of interest. It might give you some insights toward your own experiments.
http://billiards.colostate.edu/

stljohnny
05-28-2011, 12:42 PM
If you look at some of the other videos, the masse and jump shots - you'll see that whoever is performing the shot isn't hitting the CB very well. The masse shot, for example, the cue doesn't even follow through to the cloth. For the jump shot, the comes in near the top of the cue ball at a very shallow angle. Also, for the draw shot, the cue comes up after contact, where normally it'd follow through to the cloth and maybe even get some shaft-bend.

Still - interesting videos, would like to see more - with more left and right english on some shots.

dr_dave
05-28-2011, 02:11 PM
Hi all.
I have long wanted to see what happens with cue when a cue shot. Videos, which is presented on the Internet does not fully reflect the process, but I have not my own opportunity to do such video:thumbup:. However, recently met a kindred spirit who could do it. That's what happened to date.
I tried to submit a video in English, do not judge strictly for errors in translation.

Here, my friend's article about a wave properties of the cue. (http://dbkcues.ru/2011/05/28/let-s-try-to-check-the-harmony-with-algebra-c-a-pushkin/?lang=en)

Direct link to the article (http://dbkcues.ru/articles-2/investigation-in-some-wave-properties-of-a-billiards-cue/?lang=en)

Here the video with English shot. (http://dbkcues.ru/2011/05/28/the-first-russian-experience-with-high-speed-video-hs-video/?lang=en)

Here the video with the Follow and Draw shot. (http://dbkcues.ru/2011/05/28/new-portion-of-the-hs-video-follow-and-draw-shot/?lang=en)

Here a video about the transfer rotation between the balls. (http://dbkcues.ru/2011/05/28/is-there-a-transmission-rotation-between-the-balls-hs-video/?lang=en)

A little later I will try to provide frame by frame transcript of videos to facilitate the timing analysis of processes.

I will appreciate your ideas. So I will be grateful if you enter the grammatical errors in the article and descriptions. If there are errors, please let me know by my e-mail address (DBKCues@gmail.com). Sorry for my English:blush:. Waiting for your opinion here on the forum or on my blog (http://dbkcues.ru/?lang=en) or by e-mail (DBKCues@gmail.com). Thank you.

Good luck,
DmitryGreat stuff. Thanks for posting all of the links.

Regards,
Dave

JB Cases
05-28-2011, 05:38 PM
What's happening on this one?

http://www.youtube.com/watch?v=_IV8ZIz5auo&NR=1

I can't tell if was supposed to be a jump shot or a masse'.

But it's cool to see that it appears as if the cue tip is contacting the ball multiple times on the way down and then hits the table and the shaft lifts the cue ball.

LAMas
05-28-2011, 05:44 PM
It looks like a foul.:thumbup:

Jal
05-29-2011, 11:28 AM
Hi all.
I have long wanted to see what happens with cue when a cue shot. Videos, which is presented on the Internet does not fully reflect the process, but I have not my own opportunity to do such video:thumbup:. However, recently met a kindred spirit who could do it. That's what happened to date.
I tried to submit a video in English, do not judge strictly for errors in translation.

Here, my friend's article about a wave properties of the cue. (http://dbkcues.ru/2011/05/28/let-s-try-to-check-the-harmony-with-algebra-c-a-pushkin/?lang=en)

Direct link to the article (http://dbkcues.ru/articles-2/investigation-in-some-wave-properties-of-a-billiards-cue/?lang=en)

Here the video with English shot. (http://dbkcues.ru/2011/05/28/the-first-russian-experience-with-high-speed-video-hs-video/?lang=en)

Here the video with the Follow and Draw shot. (http://dbkcues.ru/2011/05/28/new-portion-of-the-hs-video-follow-and-draw-shot/?lang=en)

Here a video about the transfer rotation between the balls. (http://dbkcues.ru/2011/05/28/is-there-a-transmission-rotation-between-the-balls-hs-video/?lang=en)

A little later I will try to provide frame by frame transcript of videos to facilitate the timing analysis of processes.

I will appreciate your ideas. So I will be grateful if you enter the grammatical errors in the article and descriptions. If there are errors, please let me know by my e-mail address (DBKCues@gmail.com). Sorry for my English:blush:. Waiting for your opinion here on the forum or on my blog (http://dbkcues.ru/?lang=en) or by e-mail (DBKCues@gmail.com). Thank you.

Good luck,
DmitryThank you so much for pointing out the videos and the article. Lots of outstanding material there! If at all possible, could you report the weights of the cue stick and cueball used in the videos?

If I may presume, concerning the amount of rotation that can be imparted on one ball by another, it can be as high as 5/14'ths or 36% of the impacting ball's spin. This would only occur with a square (full) hit where the relative tangential surface speed at the contact point is totally due to the spin of the impacting ball. (With a cut shot, the relative tangential surface speed is due to both the impacting ball's tangential velocity component, as well as any spin on it.) In order for it to be as high as 36%, there has to be enough friction to reduce the relative surface speed to zero during the collision (i.e., the balls end up rolling across each other, so to speak.) This happens often enough. The 5/14'ths figure comes from the moment of inertia of a uniformly solid sphere, which we're assuming.

Thanks again and looking forward to any further offerings by you and your friends.

Jim

DBK
05-30-2011, 12:31 AM
Thanks to all for your kind words.

What's happening on this one?

http://www.youtube.com/watch?v=_IV8ZIz5auo&NR=1

I can't tell if was supposed to be a jump shot or a masse'.

But it's cool to see that it appears as if the cue tip is contacting the ball multiple times on the way down and then hits the table and the shaft lifts the cue ball.
It looks like a foul.:thumbup:
Absolutely true. :)
Please do not treat these videos as serious, it's rather funny things.;) Approximately the same as the last fragments of unsuccessful shots in the movies with Jackie Chan.:rotflmao:

DBK
05-30-2011, 12:40 AM
Thank you so much for pointing out the videos and the article. Lots of outstanding material there! If at all possible, could you report the weights of the cue stick and cueball used in the videos?

If I may presume, concerning the amount of rotation that can be imparted on one ball by another, it can be as high as 5/14'ths or 36% of the impacting ball's spin. This would only occur with a square (full) hit where the relative tangential surface speed at the contact point is totally due to the spin of the impacting ball. (With a cut shot, the relative tangential surface speed is due to both the impacting ball's tangential velocity component, as well as any spin on it.) In order for it to be as high as 36%, there has to be enough friction to reduce the relative surface speed to zero during the collision (i.e., the balls end up rolling across each other, so to speak.) This happens often enough. The 5/14'ths figure comes from the moment of inertia of a uniformly solid sphere, which we're assuming.

Thanks again and looking forward to any further offerings by you and your friends.

Jim

Thanks Jim,

Cue weight about 710 grams (25 ounces), the weight of Russian balls about 280 grams (10 ounces), the tip diameter about 12.3 mm, the tip of the first video is poor Triangle (note it vibration after impact), the second part of the video a new Moori M .

Sorry for my English. You mean that 36% is the maximum possible part of the spin that can be imparted on one ball by another in this experiment? If so, why and where it has been proven?

And please explain what is 5/14'ths ?:blush: Maybe in PM. Thanks. Dmitry.

JB Cases
05-30-2011, 01:25 AM
It looks like a foul.:thumbup:

Yes I know but I wanted to know the context.

Jal
05-31-2011, 03:21 AM
Thanks Jim,

Cue weight about 710 grams (25 ounces), the weight of Russian balls about 280 grams (10 ounces), the tip diameter about 12.3 mm, the tip of the first video is poor Triangle (note it vibration after impact), the second part of the video a new Moori M .

Sorry for my English. You mean that 36% is the maximum possible part of the spin that can be imparted on one ball by another in this experiment? If so, why and where it has been proven?

And please explain what is 5/14'ths ?:blush: Maybe in PM. Thanks. Dmitry.And thank you for the feedback on on the cue stick/cue ball, Dmitry. If I get some time, I'd like to maybe take some measurements off the videos to check a few things out.

I don't know what your background is in physics, but you can find a derivation of that ~36% (5/14) figure in one of Dr. Dave's technical proofs on this page (see TP A.27 - Spin Transfer):

http://billiards.colostate.edu/technical_proofs/index.html

If I can try to summarize while leaving out most of the math, consider a friction force acting tangentially on the surface of a solid sphere of uniform density (e.g., a pool ball :)). Suppose whatever is exerting that force is essentially immovable, for instance, the bed of a billiard table - but this discussion is not limited to that.

As a result, the surface of the ball, say, at the point of contact, will undergo a change of surface speed. (Of course, if it was at rest to begin with, then the change will be from zero to some non-zero speed.) The change in surface speed will be expressed in two ways: a change in velocity of the ball as a whole (translational velocity in the direction of the force), and a change in spin rate, with the change of surface speed at the point of contact, due to the change in spin rate, also moving in the direction of the force.

Given that the ball has mass m, and moment of inertia of (2/5)mR^2, it turns out that the total change in surface speed, let's call it d_Vs (delta Vs), is divided between changes of translational velocity and spin as follows: The change in velocity is (2/7)d_Vs, while the change in spin rate multiplied by the radius of the ball is (5/7)d_Vs. (The change in surface speed due to a change in spin is equal to the radius multiplied by the change in spin rate.)

Suppose the thing exerting the force is no longer immovable, but is another ball. At the point of contact, you initially have some relative surface speed, call it Vs. Since the friction force acts to reduce (or eliminate) this surface speed, and since it acts equally but in opposite directions on the two balls, the relative surface surface speed is reduced (or eliminated) by the friction twice as fast, so to speak. That is, both balls react to the friction and participate equally to shed surface speed.

So if a certain amount of relative surface speed is gotten rid of, call it d_Vs again, only half as much as in the previous case of the immovable agent will be attributable to each individual ball. In other words, instead of a ball undergoing a change of translational velocity of (2/7)d_Vs, it'll now undergo a change of (1/7)d_Vs. Likewise, the change in surface speed due to a change in spin rate will now be (5/14)d_Vs, instead of (5/7)d_Vs.

In a head on collision, all of the relative tangential surface speed (Vs) is due to whatever spin one or both balls happen to have. If this is reduced to zero during the collision, and one ball was at rest to begin with, then it follows that that ball will end up with 5/14 of Vs as spin. Since Vs was completely due to the spin on the moving ball, it'll have picked up 5/14 of that ball's spin. And 5/14 x 100 = 35.7%.

As an example, with a softly hit straight shot, it's been observed that maximum throw (maximum induced sideways velocity component) occurs when using about half of maximum sidespin (english). This corresponds to striking the cueball at 1/4 of a ball radius off-center. (Maximum throw takes place when the relative surface speed is reduced to zero just at the very end of the collision.) In this case, then, you can get about 36% x 1/2 or 18% of the maximum spin you can put on the cueball (for a softly hit cueball, that is). When hit harder, maximum throw occurs at lesser offsets.

As I indicated, I don't know your background and I may have just bored the heck out of you. But if you want more elaboration on those 2/7 and 5/7 numbers mentioned earlier, let me know, here or in a PM. They come quite directly (i.e., not much math) from the reaction of a ball to a force and the accompanying torque when the force acts off-center.

As an aside, I don't think there's any reason to apologize for your English. You write quite well.

Jim

DBK
05-31-2011, 12:55 PM
Yes I know but I wanted to know the context.

This is simply an unsuccessful attempt to perform masse. Unplanned and unsuccessful experiment. Shown only for fun :). Do not take it seriously.:wink:

DGunter
05-31-2011, 01:04 PM
@Jal Not gonna lie...my head just assploded a little bit.

DBK
05-31-2011, 01:26 PM
And thank you for the feedback on on the cue stick/cue ball, Dmitry. If I get some time, I'd like to maybe take some measurements off the videos to check a few things out.

My main problem now is lack of free time to closely engage the theory:sorry:. In addition, more I practice in the cue building, more I realize that an adequate model of the cue is almost impossible, and must give preference to the empirical methods of research. Therefore, these experiments with the video were chosen. And a case which introduced me to Alexander Sorokin can be termed as a happy occasion:thumbup:.

We do not engage yet in numerical analysis of the resulting video. However, if you deem it possible for yourself to do some analysis of this video, we'll be very grateful. My blog is at your disposal for the publication of the results.

I don't know what your background is in physics, but you can find a derivation of that ~36% (5/14) figure in one of Dr. Dave's technical proofs on this page (see TP A.27 - Spin Transfer):

http://billiards.colostate.edu/technical_proofs/index.html

If I can try to summarize .......

I was misled by unknown to me letter abbreviation. Now it is clear that this is the maximum share of transfer spin that meets 36%. Thanks for the clarification. I will carefully read the full version, but your explanation is quite clear. Thank you.

As I indicated, I don't know your background and I may have just bored the heck out of you. But if you want more elaboration on those 2/7 and 5/7 numbers mentioned earlier, let me know, here or in a PM. They come quite directly (i.e., not much math) from the reaction of a ball to a force and the accompanying torque when the force acts off-center.

Do not worry. You did not speak into the void:wink:. In 1992 I defended my dissertation, technical science, about the dynamics of the manipulator for building. Certainly 1992 was a long time, but I hope my head is still not completely clogged with sawdust from cues :D.
I would appreciate any information. How you see fit, here or in PM. Thank you.

As an aside, I don't think there's any reason to apologize for your English. You write quite well.

Thank you. Nevertheless, I do not feel very confident with my English.

Good luck
Dmitry

DBK
05-31-2011, 01:33 PM
@Jal Not gonna lie...my head just assploded a little bit.

:rotflmao1: :killingme:

Simple
05-31-2011, 01:35 PM
The more you post, the better your english is :)
Great videos as I already said.

DBK
05-31-2011, 01:38 PM
Great stuff. Thanks for posting all of the links.

Regards,
Dave

Dear Dr. Dave. If you find this video interesting enough to publish it in your video library, we will not have any objection. This applies to our video which will be in the future. Consider this a formal resolution. Thank you.

dr_dave
05-31-2011, 03:41 PM
Dear Dr. Dave. If you find this video interesting enough to publish it in your video library, we will not have any objection. This applies to our video which will be in the future. Consider this a formal resolution. Thank you.Thank you. I will add links to all of your stuff as soon as I can find some time. I'm very busy the next two weeks, but I'll get to it soon.

Regards,
Dave

JB Cases
05-31-2011, 04:13 PM
This is simply an unsuccessful attempt to perform masse. Unplanned and unsuccessful experiment. Shown only for fun :). Do not take it seriously.:wink:

Not taking it seriously. I just found the actual motion quite interesting and beautiful. I think most people wouldn't agree that the shaft and cue ball could contact each other multiple times like that on a miscue.

Thank you for the videos.

dr_dave
05-31-2011, 04:24 PM
I think most people wouldn't agree that the shaft and cue ball could contact each other multiple times like that on a miscue.People who think that should also look at this video:
HSV B.36 - various miscues with double-hit rule interpretation (http://billiards.colostate.edu/high_speed_videos/new/HSVB-36.htm)
And if they want to see more examples, others are linked here:
http://billiards.colostate.edu/threads/fouls.html#miscue

Regards,
Dave

Jal
05-31-2011, 09:13 PM
@Jal Not gonna lie...my head just assploded a little bit.Sorry about the trauma, whichever end it occurred at. :) :) :) On a lighter note, though, trying to express in the vernacular what is best described succinctly with math can be a challenge, at least for some of us. You tend to get a little wordy and end up making it seem more complicated than it is.

Jim <--- has never, ever done that

DBK
06-12-2011, 05:33 AM
Another couple of HS-video. Now 24,000 fps.! Cool :thumbup:. And one video for fun:). What happens with hand on V-bridge when is Miscue? Nightmare :shocked2::). Homo sapiens = more than 80% of water.:D

HS-video 24,000 fps. (http://dbkcues.ru/2011/06/12/another-couple-of-hs-video-now-24-000-fps/?lang=en)

Here, the central shot. The first - cue with fenolik tip. This was necessary to have a reference point of contact time of net cue, without a leather tip. Characteristically, the contact time is almost independent of the cue speed in the first case with phenol tip, and is about 0.8 milliseconds.
Contact time the cue with the usual tip depends on the speed of the cue, and the smaller, the higher the speed of the cue. The pictures show the time of contact the cue tip with the cue ball, depending on the speed of the cue.

http://s004.radikal.ru/i205/1106/28/44b89f145701.jpg

http://s57.radikal.ru/i156/1106/8f/6dcb3e973406.jpg
Re.: (The inscriptions on the pictures, the vertical axis - the contact time (ms), the horizontal axis - cue speed (m / s), at the first at the top (Oleg's cue), the second top (Dmitry Komarov's cue)

paulempor
06-12-2011, 09:15 AM
Amazing stuff. Thank you for posting and sharing with us.

Paul

Siz
06-12-2011, 02:14 PM
Another couple of HS-video. Now 24,000 fps.! Cool :thumbup:. And one video for fun:). What happens with hand on V-bridge when is Miscue? Nightmare :shocked2::). Homo sapiens = more than 80% of water.:D

HS-video 24,000 fps. (http://dbkcues.ru/2011/06/12/another-couple-of-hs-video-now-24-000-fps/?lang=en)



http://s004.radikal.ru/i205/1106/28/44b89f145701.jpg

http://s57.radikal.ru/i156/1106/8f/6dcb3e973406.jpg
Re.: (The inscriptions on the pictures, the vertical axis - the contact time (ms), the horizontal axis - cue speed (m / s), at the first at the top (Oleg's cue), the second top (Dmitry Komarov's cue)

Very interesting. What is the difference between your tip and Oleg's? There seems to be a big difference in contact times at low speeds. Was it the same person using both cues?

Petros Andrikop
06-12-2011, 02:36 PM
Amazing work, as well as Dr Dave's. Thank you for sharing.
Petros

JB Cases
06-13-2011, 04:09 AM
Another couple of HS-video. Now 24,000 fps.! Cool :thumbup:. And one video for fun:). What happens with hand on V-bridge when is Miscue? Nightmare :shocked2::). Homo sapiens = more than 80% of water.:D

That's great. I don't know if this has any bearing on the discussion but whenever I shoot with a Predator shaft and miscue then it raps my knuckles like someone hit me with a ruler. It actually hurts and even more so if I shoot with a P2 (the one with the spliced butt).

This is the only cue where that happens to me.

Gwenn
06-14-2011, 06:55 AM
Thanks for the videos, guys.

The most interesting fact that the videos show (for me) is, that the tip of the shaft initially can bend towards the cueball. This definitely classifies the "bending" of the cue stick as a result of an impulse generating waves which travel the shaft, as opposed to some more "common" magical force interpretations. This also seconds your piezzo experiments.

What I'm interested in all the "squirt" discussion are the effects in relation to each other:

- Endmass: To which average percentage does it contribute in different material and taper situations
- transverse waves: to what degree do they tend to increase end mass, and what's the average percentage they contribute to squirt for typical cue materials and builts.
- longitudinal waves: pretty much the same.

More or less a decomposition of squirt into these factors.

Regards
Gwenn

DBK
06-14-2011, 11:16 AM
Thank you all for your attention to the topic.

Very interesting. What is the difference between your tip and Oleg's? There seems to be a big difference in contact times at low speeds. Was it the same person using both cues?

My friend Oleg and I have provided cues for these experiments. In the video Oleg's cue fenolik tip and on my MooriM. Cues a little different in characteristics, so the contact time is different. What parameters affect the correct play the cue is not yet clear. We still have to check. Yes, all the shots played by one person.

DBK
06-14-2011, 11:25 AM
Thanks for the videos, guys.

Welcome :)

The most interesting fact that the videos show (for me) is, that the tip of the shaft initially can bend towards the cueball.

Here, everything is logical. Because the tip contacts the cue ball only by the one side appears the moment of force that bend the shaft towards the cue ball in the first instant of contact. This was expected, but we could see only now.


What I'm interested in all the "squirt" discussion are the effects in relation to each other:

- Endmass: To which average percentage does it contribute in different material and taper situations
- transverse waves: to what degree do they tend to increase end mass, and what's the average percentage they contribute to squirt for typical cue materials and builts.
- longitudinal waves: pretty much the same.
More or less a decomposition of squirt into these factors.


Thank you.

We are planning several more series videos. Maybe this will be a variation with endmass and its effect on the cue ball throw. It might be an attempt to take the video full length cue to see the waves. Maybe will be a series of videos with pool cues.

Concerning the analysis of the resulting video, it's not a quick thing. Most likely for the long winter evenings:). So join us:wave3:. I will try to put every video in the as a set of individual frames. I will give this link further.

DBK
02-10-2012, 12:29 AM
A new article about the collision of billiard balls
http://dbkcues.ru/2012/02/10/new-article-about-the-collision-of-billiard-balls/?lang=en

Also a lot of new HSvideo . I'll try to put the most interesting links soon.

Shaky1
02-10-2012, 04:22 AM
That looks like a ld shaft? I'd love to see it with an old Meucci!

Simple
02-10-2012, 04:37 AM
Where did you see a ld shaft?

Shaky1
02-10-2012, 04:45 AM
I'm just guessing by looking at the short ferrule?

Simple
02-10-2012, 04:49 AM
I can't see any ferrule in this article :o
But fyi DBK installs such a ferrule on all his shafts since 2 years afaik.
BTW it's about russian pyramid balls in this article.

Shaky1
02-10-2012, 04:53 AM
The videos are in the link about 4 replies above.

Bob Jewett
02-10-2012, 10:03 AM
Disclaimer. This is NOT an attempt to knock the videos!!

From the video, it doesn't look like they are laying a very good stroke on the cueball.
Kind of looks like a poke stroke.

I might be way off, but it almost looks like they are bunting the ball with no follow through. Almost stopping after contact. With zero hang time for the tip on the cueball.

I only say this because of the speed at which the cueball leaves the tip, and the increasing distance between tip and cueball after the shot.
It seems like it's too much distance, too fast, especially for slow-mo.

Maybe that is a result of the slow-mo effect, but something just doesn't look right.

But either way, thank you for the videos.
It is the effect of the slow motion. When the stick hits the ball, the cue slows down almost instantaneously to 50% of its speed just before contact. At the same time, the cue ball leaves the tip with about 130% of the speed of the stick just before contact. This effect is seen in all the high speed pool videos. I agree that it looks very strange, but that's the way that shots work. It gives you a completely different view of stroke and such.

The hardest part of these videos for some people to accept is the very short contact time. Some players think it is very important to increase the contact time, but by studying the videos you can see that it is probably neither possible nor desirable to do that.

Bob Jewett
02-10-2012, 10:08 AM
First, thanks for the videos. Very nice quality.
...
We are planning several more series videos. Maybe this will be a variation with endmass and its effect on the cue ball throw. ...
In American English, it is not called "throw". It is called "squirt" or "cue ball deflection". The word "throw" for most American pool players means the sideways effect of friction at the contact point between balls and has nothing to do with cue stick characteristics.

I think UK/snooker players do refer to the effects of endmass as "throw."

Bob Jewett
02-10-2012, 10:21 AM
Another couple of HS-video. Now 24,000 fps.! Cool :thumbup:. And one video for fun:). What happens with hand on V-bridge when is Miscue? Nightmare :shocked2::). Homo sapiens = more than 80% of water.:D ...
It is very interesting to see the longitudinal vibrations. I have written a simple simulator which predicts these but was never able to see them before. The simulator predicts (obviously) that the amplitude of the vibration will be larger with a harder tip due to the shorter contact time that causes more energy to be left in the cue stick as longitudinal compression. Have you been able to extract the amplitudes and frequency of the vibrations?

In the US there was an add-on product that was for these vibrations or maybe the transverse vibrations. It was a soft material that went on the end of the butt as a damper. If you have any spare time ;) you might try an experiment with such a thing.

Thanks again for your work.

dr_dave
02-10-2012, 11:03 AM
It is the effect of the slow motion. When the stick hits the ball, the cue slows down almost instantaneously to 50% of its speed just before contact. At the same time, the cue ball leaves the tip with about 130% of the speed of the stick just before contact. This effect is seen in all the high speed pool videos. I agree that it looks very strange, but that's the way that shots work. It gives you a completely different view of stroke and such.A good illustration and explanation of this effect can be found here:
stroke and cue acceleration resource page (http://billiards.colostate.edu/threads/stroke.html#acceleration)

The hardest part of these videos for some people to accept is the very short contact time. Some players think it is very important to increase the contact time, but by studying the videos you can see that it is probably neither possible nor desirable to do that.Good point, although it can still help some people to think: "Accelerate through the ball" or "Keep the tip on the ball longer" even though these things aren't strictly possible. These "imaginary mental images" might help them avoid decelerating into the ball, which can have negative consequences.

BTW, a lot more info (and video demonstrations) dealing with cue tip contact time can be found here:
cue tip contact time resource page (http://billiards.colostate.edu/threads/cue_tip.html#contact)

Regards,
Dave

dr_dave
02-10-2012, 11:36 AM
Dear Dr. Dave. If you find this video interesting enough to publish it in your video library, we will not have any objection. This applies to our video which will be in the future. Consider this a formal resolution. Thank you.FYI, I've added links to your excellent resources, along with some others, here:
cue vibration resource page (http://billiards.colostate.edu/threads/cue.html#vibration)

Again, great work!!!

Show us more if possible. Feel free to duplicate some of the stuff on my high-speed-video page (http://billiards.colostate.edu/high_speed_videos/index.html) if you want some ideas. Your camera is much better than mine.

Regards,
Dave

Bob Callahan
02-10-2012, 12:10 PM
Thanks for posting this information. For me as a science guy, it is very interesting, and adds to a more complete model of the physics of billiards.

I think though, that the typical reader will be thinking, "How does this help me be a better player?"

So...what do you think the practical benefits of this type of research will be to players?

Mr. Bond
02-10-2012, 07:17 PM
Horosho Mr. Komarov

Spasibo!

DBK
02-11-2012, 05:12 AM
Thank you for your kind words:smile:. We will try to make a lot of interesting video. But for this, of course, need a lot of time and patience. However, success also did not interfere.;)

First, thanks for the videos. Very nice quality.
In American English, it is not called "throw". It is called "squirt" or "cue ball deflection". The word "throw" for most American pool players means the sideways effect of friction at the contact point between balls and has nothing to do with cue stick characteristics.
I think UK/snooker players do refer to the effects of endmass as "throw."

Thanks for the correction and sorry for my english.:blush:

DBK
02-11-2012, 05:16 AM
Thanks for posting this information. For me as a science guy, it is very interesting, and adds to a more complete model of the physics of billiards.

I think though, that the typical reader will be thinking, "How does this help me be a better player?"

So...what do you think the practical benefits of this type of research will be to players?

Interesting question. I think it is important the eternal human desire for knowledge. Humans always wants to know why this happens :smile:. However, I think that there are practical benefits now too. First of all, for cuemakers. They can see some of the processes that help or hinder the cue stick strikes, conceived by the player.

DBK
02-11-2012, 05:18 AM
We plan to repeat some shooting with pool cues and balls, which have already been made for the Russian cues. I think it will be interesting.

We plan to continue filming the series with increased attention towards the working of tips. This is one of the most important moments in the structure of the cue, and an understanding of the principles of how tips work is very important.

Have an idea to hold a series of shootings with different hardness tips at the same cue. However, it takes a long time to change the tips. It would be much more convenient to have several identical cues, so as not to lose time to replace the tip. For the Russian cue it is unrealistic, they are all unique. But for a pool cue is quite possible If we would have 3 or 4 of the same shaft. For example Predator.

Here in Russia purchase such shafts is very difficult. In addition, we are very limited in funds. Therefore, I have a request.

Maybe someone from AZ members interested in this project and can send 3 or 4 partial Predator shafts for the research. For soft, medium and hard tip, plus one control is desirable. I will be able to do a stiff butt for these shootings. It can get very interesting results.

Also available a series of shootings of different stiffness shaft, from a very hard hornbeam shaft to the shaft of a soft maple species. These shafts I can make, but several of the same I can not .

Bob Jewett
02-11-2012, 09:09 AM
... Have you been able to extract the amplitudes and frequency of the vibrations?

In the US there was an add-on product that was for these vibrations or maybe the transverse vibrations. It was a soft material that went on the end of the butt as a damper. If you have any spare time ;) you might try an experiment with such a thing. ...
Here is a thread about that vibration-damping product that just started: http://forums.azbilliards.com/showthread.php?t=263779

DBK
02-11-2012, 11:52 AM
Horosho Mr. Komarov

Spasibo!

Pozhalujsta :) :welcome:

This is some videos that I promised in addition.

"Go home"
http://www.youtube.com/watch?NR=1&v=IyEFl06j6Vw&feature=endscreen

Machine gun
http://www.youtube.com/watch?v=Z24qAezJdj4

Kiss-shot
http://www.youtube.com/watch?v=Z15pr3lPFzQ


STANDARD SHOTS

Draw shot
http://www.youtube.com/watch?v=vHVukoUUaBg

Follow shot
http://www.youtube.com/watch?v=5rEarbexUYw

Foul on the close pair
http://www.youtube.com/watch?v=4grN1WoXikY

Close pair by Follow shot (legal)
http://www.youtube.com/watch?v=dDqS2fgomQs


JUMPS
Weight of the ball 280 grams (9.9 ounces)!!!!

Jump through the ball
http://www.youtube.com/watch?v=Y5WeNlz8fJE

A bad jump through the coins
http://www.youtube.com/watch?feature=endscreen&NR=1&v=7cNyGJW_lFA

Do not stand in the way
http://www.youtube.com/watch?v=sOJQbs8ZHq8


DEFORMATION OF CUSHIONS

Pushing to the middle pocket
http://www.youtube.com/watch?v=Q3fBDzgUDVI

Pushing to the corner pocket
http://www.youtube.com/watch?v=KlPAVZz7j2I

close balls we sometimes call "the hares"
http://www.youtube.com/watch?v=tlYsJSr284E

deformation of the side in profile
http://www.youtube.com/watch?v=GBCSiGlixBU


For the following shots explain that in the Russian billiards cue ball, pocketed according to the rules, is counted as legal.

In Russia jump an object ball to pocket is often called a "basketball shot".

"Basketball shot" to the corner pocket
http://www.youtube.com/watch?v=WQ1cu0zFXY8

"Basketball shot" to the middle pocket
http://www.youtube.com/watch?v=F_Gvf3qSY0w

The pair close the middle pocket, or "Open the Gate, Cue Ball came.":)
http://www.youtube.com/watch?v=932igV1wVvg

Kick shot.
http://www.youtube.com/watch?v=kuFRXBnt6tM

cue ball 1
http://www.youtube.com/watch?v=a02pHqfxRrQ

cue ball 2
http://www.youtube.com/watch?v=68EpYIsP0iI

DBK
02-11-2012, 12:20 PM
One more video.:thumbup:
For those who not familiar with Russian billiards and afraid of heavy balls
and cues ;). I highly recommend to watch this match :thumbup2:. Almost absolutely perfect game of my young friend.

Record from Web broadcasts. The first nine minutes of video is a warm-up before the game, total time about 37 minutes.

Enjoy it here.

http://t.llb.su/video.php?comp=4474&game=461

or here

http://bambuser.com/v/2351483

DBK
04-15-2012, 02:17 AM
Recently made some new videos. But need the time to analyze it. For example here are a couple of controversial shots at close-standing balls.

http://www.youtube.com/watch?v=EHXWfQM26vE
http://www.youtube.com/watch?v=z7a8MLOmzcg

And one more news :thumbup:. Soon machine to simulate cue shot to be completed :dance:. Here the picture.
http://s019.radikal.ru/i623/1204/a3/3576e2618b97.jpg

And the first video in work.
http://www.youtube.com/watch?v=cbo3hoiNf8g

Alexander Sorokin very purposeful person :clapping:. This high speed video and this machine is mainly his work. Let's all wish him success.:thumbup2:

Bob Jewett
04-15-2012, 10:26 AM
Recently made some new videos. But need the time to analyze it. For example here are a couple of controversial shots at close-standing balls. ...
Thanks for the new videos. The web site http://dbkcues.ru/ seems to have gone away. I hope it is a temporary problem.

DBK
04-17-2012, 11:14 PM
Thanks for the new videos. The web site http://dbkcues.ru/ seems to have gone away. I hope it is a temporary problem.

Thanks Bob. Quite a strange situation was, not have any notice or bills, which we have not paid. Nevertheless, the service has been suspended. But now everything is normal. :smile:

DBK
12-16-2012, 07:28 AM
The new article of Alexander Sorokin describing the CUE testing unit. A very interesting additions to the design of the machine.:thumbup2:
http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en
When testing the cue, especially in a comparative test, the main problem is subjectively factor. Well, is not given to man to accurately reproduce the motion and force of impact cue. Each time the strike would be any different from the last. Resolve this uncertainty can only mechanical system, which every time will execute one and the same operation, quite accurately repeating the same impact parameters. I admire the enthusiasm of Alexander Sorokin, who made such apparatus. What apparatus? Judge for yourself.
In my opinion the design is rather witty and reliable.

Siz
12-16-2012, 03:07 PM
The new article of Alexander Sorokin describing the CUE testing unit. A very interesting additions to the design of the machine.:thumbup2:
http://dbkcues.ru/articles-2/cue-testing-unit/?lang=en
.

Wow! Very impressive. :thumbup:

Do you have copies of those graphs with the legends in english?

Bob Jewett
12-16-2012, 06:00 PM
Thanks for the update.

I thought the contact time vs. stick speed graph was particularly interesting. I assume that the time was measured with with the high-speed video. I don't know of any theory that predicts that shape of dependence.

WFD
12-16-2012, 06:55 PM
Interesting videos and machine. Look forward to see more viddeos in the future.

PS! I look forward too visit russia and play pyramid again in the future )

DBK
12-18-2012, 12:14 AM
Thank you. I conveyed to Alexander your respect. :)

Wow! Very impressive. :thumbup:

Do you have copies of those graphs with the legends in english?

You mean like this? A little later, I will change them on the blog.

http://dbkcues.users.photofile.ru/photo/dbkcues/200646425/210356287.jpg
http://dbkcues.users.photofile.ru/photo/dbkcues/200646425/210356293.jpg
http://dbkcues.users.photofile.ru/photo/dbkcues/200646425/210356290.jpg
http://dbkcues.users.photofile.ru/photo/dbkcues/200646425/210356292.jpg

Siz
12-18-2012, 05:13 AM
Thank you. I conveyed to Alexander your respect. :)
You mean like this? A little later, I will change them on the blog.


Yes, that's it.

Thanks Dmitry

Siz
12-18-2012, 05:18 AM
Thanks for the update.

I thought the contact time vs. stick speed graph was particularly interesting. I assume that the time was measured with with the high-speed video. I don't know of any theory that predicts that shape of dependence.

Was this a laminated tip?

Perhaps up to the the inflection point, the upper layer(s) of leather compress (with max compression being reached over shorter intervals as the cue velocity increased); then after the inflection point, with sufficient velocity a relatively inflexible barrier formed by a glue layer is overcome and lower layers start to compress more quickly?

Just a thought ...

Re-edited: "more quickly" added at the end for clarification. (The lower layers must have been compressing before the suggested deformation of the boundary layer - otherwise it would be a minimum rather than an infection point. What could be happening is that the deformation causes this compression to speed up, perhaps because the barrier is no longer spreading the force so effectively.)

DBK
03-23-2014, 01:10 PM
New article - A.Sorokin "Ball Motion Properties in Stun and Follow Shots"

"Anyone who has had the opportunity to learn the basics of billiards whether Pool, Snooker, Carom, or Russian Pyramid certainly knows the two basic rules which describe the motion of balls after collision. These are the so-called 90- and 30-degree rules.
This study attempts to demonstrate how these rules work for Russian Pyramid using high-speed video." (с)
Read here. http://dbkcues.ru/articles-2/ball-motion-properties-in-stun-and-follow-shots/?lang=en

The Renfro
03-23-2014, 02:06 PM
Welcome back.... Am always interested in seeing what you guys have been working on..... :thumbup: