View Full Version : How Much Throw Can English Induce?
04-28-2002, 01:25 PM
Has anyone quantified how much an object ball can be thrown when hit with a cueball spinning with english? I know figuring how much a ball will throw is largely a matter of feel, but I wonder if anyone has measured it for certain angles, distances and amount of english, etc.?
Lots of variables at work here, perhaps the greatest one being the condition of the balls....clean or dirty, dry or damp or sticky. A dirty ball will cling and throw much more than a clean one. A clean and polished ball won't throw much at all. I don't know of any way to calculate the throw mathematically.
04-28-2002, 03:28 PM
Tom, as Vapros said, it depends on several variables, mostly the slickness of the surface of the balls. Jack Koehler, in his book The Science of Pocket Billiards, devotes considerable attention to the topic of "english-induced throw." According to his book, the maxmimum english-induced throw, in terms of degrees, is about 5 degrees. This translates into an error at the pocket of about 4 inches when the object ball is about 4 feet from the pocket at the beginning of the shot. The magnitude of the throw depends on the cut angle, with a zero angle (straight in shot) produces the most throw. Throw is greater with outside english as opposed to inside english. Finally, his figures resulted from experiments with clean balls. If the balls are dirty or have a spot of chalk on their surface, you will get a greater degree of throw. Jack's book has a pile of this kind of information produced by laborous and careful experiments.
04-28-2002, 11:30 PM
As others have mentioned, see Jack Khoeler's book for more details. Also see Ron Shepard's APAPP. He arrives at the interesting conclusion that throw is maximized for "stun" shots with sidespin, that is, shots that have the cueball SLIDING into the object ball. For shots with a combination of draw or follow and sidespin, the throw is slightly reduced due to the extra surface sliding speed (reducing the friction). This implies that to get maximum throw, you want to stun the cueball, not apply slight draw as has been previously thought.
5 degrees can be easily achieved with "normal" pool hall condition balls. Very new or clean or polished balls will naturally throw less, while very dirty balls will throw more.
Generally speaking, approx. one inch for every foot of length to the shot. GF
Can someone tell me if inside english will "throw" the same degree as outside? If one tip of outside english produces 1" of throw for every one foot of travel, is it the same for inside (a deviation of 1" per ft also?)
05-02-2002, 06:02 PM
Object ball on the foot spot, cue ball about 6 inches straight behind the OB (between OB and foot rail).. With left or right hand english, you should be able to shoot the OB down table with enough throw and spin to be able bank the OB into a corner pocket.
I've never heard, read or observed anything to suggest otherwise, Curt; English is English. I've sung the praises of inside English to the heavens in my book, but inducing more throw than outside English is not one of its virtues. GF
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