Cie
- Thread starter lfigueroa
- Start date
Guess
Id like to guess and I would say a 1/3 ball cut not sure what angle that is though...
Id like to guess and I would say a 1/3 ball cut not sure what angle that is though...
Most throw with cut only = 30 degrees (1/2 ball) cut
Most throw with spin only (straight shot) = 1/2 maximum spin
Most throw either way = slow, sliding CB
pj
chgo
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Wait, wait, don't tell me...
IIRC it is 30 degrees, or the infamous 1/2 ball hit.
Speed.
AFAIK, as with CB spin, the harder you hit the CB, the less effect you get.
My impression, based on my personal experience is that draw or follow
would produce a lesser effect than center ball, but that 'drag draw'
would give the most(as Patrick said)
YMMV
Dale
Just to add, more throw means more induced spin on the OB.
Given the same translational speed of the CB, draw and follow tend to reduce throw. More specifically, they do this by 1) increasing relative surface speed at the contact point, which reduces the friction, and/or 2) orienting the direction of the friction more upward or downward, thus, generally speaking, reducing the horizontal component of throw. (There are exceptions which occur at mild cut angles with just a touch of draw or follow. Here, they neither diminish throw in whatever direction the friction force is pointing, nor do they reduce the horizontal component.
You get maximum throw when the balls slide across each other during the entire collision, but just reach the point where they're rolling across each other (gearing) at the very end of the collision. This can take place at cut angles somewhat greater or lesser than 30 degrees (half-ball hit), depending on how "sticky" the balls are and shot speed. But 30 degrees is a good average and an obvious landmark.
A very minor and frankly pedantic point is that draw and follow induce a slight masse component of spin on the OB. The subsequent "curving" of the object ball reduces overall "throw" in the case of draw, and increases it in the case of follow. These effects, however, are very tiny and of no real practical consequence.
Jim
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I think the CB is spun the same amount in the opposite direction and slowed the same amount that the OB is thrown, if that's what you're asking.
pj <- propeller head trainee
chgo
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Very true, Patrick, except the spin, or change in spin induced on the CB is in the same direction as on the OB. So without any pre-collision spin on the CB, for instance, a cut to the left induces right english on both balls. If the CB already has some english, say left, then it'll come away with less left (i.e., add the newly induced right english to its pre-existing left english). Likewise, if it has right english and right english is induced on the OB, the CB will come away with that much more right english. If it has right english and left english is induced on the OB, it'll come away with that much less right english.
The same can be said if you mix in draw or follow.
I don't now if the the above sounds confusing. The simplest way of putting it, I think, is along the lines you indicated. Whatever spin the OB picks up, add that same spin to the spin the CB had before the collision and that's what the CB will leave with.
On the face of it, this all seems to be a blatant violation of the principle of conservation of angular momentum. It seems as if nature is being unduly generous granting both balls more spin (in some cases) than they had going in. But there's a more general form of angular momentum at play other than the spinning balls. The principle is safe.
Jim
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There was a post a few days ago that said the CB picks up spin when hitting an OB, and you need to account for that spin when playing position. I was not sure if this was true, so I went to the table and tried a few shots.
I set up 3 frozen balls in a straight line, using the edge of my cue to keep them straight. The 3 balls were aimed at an OB a foot away, for a half ball hit. The lead ball in the 3 ball frozen line was a striped CB. I hit the last ball of the 3 frozen balls with my cue stick, which propelled the lead ball (CB) into the OB. I used this setup to guarantee that any tip striking inaccuracy would not impart spin on the OB.
I didn't notice any spin on the CB visually. I also didn't notice any direction change when the CB hit the rail. It acted to me as if it had zero spin. I tried it a few times, with different speeds, and different thicknesses of hits.
I also recorded this on my camera, at its highest DV setting of 29 frames per second. That was not a fine enough resolution to make heads or tails of if the CB picked up spin after the impact.
So based on my limited experiment, I found that if there was a spin transfer to the CB after a collision, it was so slight it did not affect the shot.
My equipment was new 860 Simonis, that was still slippery, GC4 with good rails, and Aramith balls that were clean and ding free.
Thoughts? Thanks.
I set up 3 frozen balls in a straight line, using the edge of my cue to keep them straight. The 3 balls were aimed at an OB a foot away, for a half ball hit. The lead ball in the 3 ball frozen line was a striped CB. I hit the last ball of the 3 frozen balls with my cue stick, which propelled the lead ball (CB) into the OB. I used this setup to guarantee that any tip striking inaccuracy would not impart spin on the OB.
I didn't notice any spin on the CB visually. I also didn't notice any direction change when the CB hit the rail. It acted to me as if it had zero spin. I tried it a few times, with different speeds, and different thicknesses of hits.
I also recorded this on my camera, at its highest DV setting of 29 frames per second. That was not a fine enough resolution to make heads or tails of if the CB picked up spin after the impact.
So based on my limited experiment, I found that if there was a spin transfer to the CB after a collision, it was so slight it did not affect the shot.
My equipment was new 860 Simonis, that was still slippery, GC4 with good rails, and Aramith balls that were clean and ding free.
Thoughts? Thanks.
Nice experimental setup! Nevertheless, the CB must have picked up some spin - not a heck of a lot - but some.
Take a look the first shot on HSV B.30 from Dr. Dave (http://billiards.colostate.edu/high_speed_videos/index_alt.html).
We aren't talking about a lot of induced spin, but the same amount that can be put on an object ball. The latter is enough to affect the outcome of bank shots, for instance, so it's not zero. On the other hand, imo, cueball positioning doesn't typically require the same fine tuning and a little spin tweak isn't going to be as noticeable.
Once a ball gets rolling, it can be next to impossible to tell if it has sidespin, other than by its reaction off the cushion. You didn't see any change there, but I think you ought to be able to detect it per the bank shot example mentioned.
Jim
OK, so thank you again to the pocket protector set and those aspiring to be awarded their pocket protector.
So last question, just to be clear: is it fair to say that a 30 degree cut shot will impart the most collision induced english on a CB hit without english?
Lou Figueroa
So last question, just to be clear: is it fair to say that a 30 degree cut shot will impart the most collision induced english on a CB hit without english?
Lou Figueroa
PJ, Jal, and others have already given excellent answers. If you want more information and supporting resources, see:
Also, most throw-related effects are summarized (with supporting resources) here (see items 15-36 in the list beneath the videos):
Also, many of the important effects are demonstrated and described concisely in the following video:
... yes, in general, but it varies with speed some. The induced sidespin is also greater when the CB has stun (not top or bottom spin). Speed is a tricky thing concerning throw and spin transfer. With more speed, you can get less spin transfer, but the spin will wear off slower (e.g., on the way to a rail). When there is a large distance to a rail, a faster speed will result in the greatest induced sidespin effect (e.g., with spin transfer bank shots). You don't get quite as much transferred spin at the faster speed, but more will be retained on the way to the rail. When the ball (CB or OB) is close to a rail, slower speed will create the greatest sidespin effect.
I hope that makes sense,
Dave
This is an interesting twist (get it?)...
Dave - I'm curious what you think about this spin-rubbing-off friction. In particular we normally think of cloth as having slickness, resistance to sliding, and speed, resistance to rolling.
Which of these relates best to spin-rubbing-off?
I can see it both ways. Slickness is important because it is an actual sliding friction force/torque that is acting. Speed is important because what makes cloth fast is that the ball doesn't sit in a deep hole (and thus isn't constantly climbing a big hill). When the ball IS sitting in a deeper hole (slow cloth) the friction is acting further out from the base of the ball, where it does more damage...
Jason had the golden fleece
Sir Galahad has the holy grail
Lou has get-in-english
;-)
lol. Mike, actually I was asking because of what I was observing and trying to refine for position play.
But now that you've brought it up (and since it's my thread):
Who out there believes in "get-in" english? AND if get in english exists does that mean get-out english also does?
Lou Figueroa
Yeah, I need a more simplifed question to respond properly, so I just punt at this time and wait for Bob Jewett to get into it and clarify....
Right. I was thinking of their surfaces at the point of impact. Thanks.
pj
chgo
Just like a court of law!!! He brought it up, so now we can discuss it!!!
To me, they exist. If spin transfer affects banks shots, then banking off the face is affected by spin transfer. And some pockets like it one way (transfer of inside to the OB) and hate it the other.
Freddie <~~~ been tortured by get out english