curving an object ball....
- Thread starter John Brumback
- Start date
I finally found the time to film some video of bank-curve attempts. I wasn't able to get a convincing and useful amount of curve on my table, but I plan to try other equipment in the near future. Here's the video I just posted, which shows a variety of kick and bank shots using speed and spin to change the rebound angle and ball path:
Bending, Twisting, and Stiffening Kick and Bank Shots
The video includes the straight-back one-pocket bank brought up earlier in the thread.
It also includes my best attempt at John's shot. Notice how the ball hop and camera angle give the perception that the ball is curving some, but I think the ball actually heads very straight. If and when I film on other tables, I will use different camera angles to show this more clearly.
Enjoy the video,
Dave
Bending, Twisting, and Stiffening Kick and Bank Shots
The video includes the straight-back one-pocket bank brought up earlier in the thread.
It also includes my best attempt at John's shot. Notice how the ball hop and camera angle give the perception that the ball is curving some, but I think the ball actually heads very straight. If and when I film on other tables, I will use different camera angles to show this more clearly.
Enjoy the video,
Dave
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John,
Thanks for posting this. I snipped 3 frames of the video and carefully superimposed three OB position on the same photo. Here it is:
It looks like you did get a small amount of post-rebound OB curve. It wasn't really necessary to avoid the obstacle ball, but it certainly is noticeable. As I promised, I will attempt to get similar action on my equipment (and if it doesn't work, I try some tables at the pool hall).
Thanks again,
Dave
Appreciate this Dr. Dave. I could not definitively see the curvature in the video but it is obvious in your compiled photo.
For those interested, I just got the following e-mail question in regards to the quote above:
I agree the OB usually comes off the banking cushion with running spin, but then isn’t that also running spin on the rail next to the corner pocket? Seems to me that running spin on the rail next to the pocket would tend to embiggen the pocket (props to Lisa Simpson).
Here's my answer:
At shallow angles into a cushion, the rebound angle doesn't change much with sidespin. However, if the ball hits the near cushion and then the far pocket facing with the wrong spin, it most definitely rattles out much more easily (especially if the pocket has wide facing angles and/or a deep shelf). The spin can also hurt if you hit the far point of the pocket first. Therefore, the effective size of the pocket is smaller with the wrong spin.
Regards,
Dave
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You also didn't deploy the correct "stroking method" for getting an object ball to curve. Back to the drawing board
John B.
Must be a "SECRET"!
I'm just wondering, when you were in school, did they call you "Little Johnny"?
JoeyA
I'm just wondering, when you were in school, did they call you "Little Johnny"?
JoeyA
You also didn't deploy the correct "stroking method" for getting an object ball to curve. Back to the drawing board
One Thursday, 'little Johnny' goes to school, and the teacher informs the class that she will ask a question, and whoever guesses it right, gets to take Friday off.
So she asks the class, "How many grains of sand are there in the Sahara desert?".
Well, of course no one can answer, and this pisses 'little Johnny' off.
As the weeks go by, the teacher asks more questions like the first. "How many gallons of water are in the Pacific ocean?", "How many liters of oxygen are in the atmosphere?" etc. All questions that cant really be answered.
So Johnny has had enough. He goes down to the five and dime and gets a big bag full of black marbles. The next Thursday, right before the teacher asks the next question..... Johnny opens up his bag and rolls the marbles all over the floor.
The teacher stands up and yells "Ok...... Who is the comedian with the black balls????"
Johnny stands up and says "Bill Cosby........ see ya Monday......" :grin-square:
The bass,sauger and crappie have been bitin real good lately. Might have to go on a diet:thumbup: John B.
Ya think!!!!! LOL John
oh man, we used to argue about get in english forever, going back to RSB.
I knew it was there but I could never get the science guys to buy into it.
Lou Figueroa
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...paging Mr. Wiley...
pete
pete
I did not read through all of this thread, I just wanted to add a comment about cameras. I have a camera on my home table, and it 100% does NOT show the true position or paths of the balls. There are many reasons for this, and I'm not talking about the camera quality.
For example, on tables that have the headstrong line drawn, and a 100% overhead camera shot, the headstrong line will NOT line up with the corresponding diamonds. This is because the cloth and the rail diamonds are on a different plane. And the camera sees them completely differently.
The point of this, is I don't think anyone can reliably take freeze frames from a video, and make any accurate drawings of the path of the balls. Sure, its good enough for most things, but in this case, of trying to show the OB curve by a tiny amount, it is 100% useless.
These are my personal experiences trying all sorts of filming techniques on my home table. I also have lines drawn all over my bed cloth, at the intersection of each diamond, and the camera does not show them properly.
For example, on tables that have the headstrong line drawn, and a 100% overhead camera shot, the headstrong line will NOT line up with the corresponding diamonds. This is because the cloth and the rail diamonds are on a different plane. And the camera sees them completely differently.
The point of this, is I don't think anyone can reliably take freeze frames from a video, and make any accurate drawings of the path of the balls. Sure, its good enough for most things, but in this case, of trying to show the OB curve by a tiny amount, it is 100% useless.
These are my personal experiences trying all sorts of filming techniques on my home table. I also have lines drawn all over my bed cloth, at the intersection of each diamond, and the camera does not show them properly.
I wanna catch a Sauger too! Are they kinda like a walleye?
I completely agreed and it is one of the main reasons I have a hard time with all the WWYDs that are popular on other forums -- guys arguing to the death about the "correct shot" when they cannot possibly see the true angles.
All this was brought home to me a while back when someone pulled up a WWYD from my 1pocket match with JB. Some of the folks started suggesting shots I knew -- having been there shooting the shoot -- where not possible. That and how everyone shoots with perfect accuracy and speed on the WWYDs. Everything always comes out perfect shooting a shot on the interweb.
Lou Figueroa
I don't know but he must have been super good in math and science to be able to play like he does.
When it comes to banking "pool school", I'm sending John to the head of the class. I'll save the back row for the scientists.
Banks
Banned
My favorite is the 4-rail and it tends to bend a bit on the end.
BTW, I want to thank Bob Jewett for suggesting the maximum-kick-angle challenge shot. Honestly, I was a little surprised by the amount and direction the CB curved after rebound. I expected the observed curve direction for the masse-shot cheat, assuming some of the masses pin remained after rebound, but not for the level-cue shots, where the CB had stun (with sidespin) into the cushion. Based on explanations earlier in the thread, one might have expected the CB to curve in the opposite direction since a ball stunned into a cushion usually picks up topspin on the rebound. Topspin would cause the CB to curve in the other direction, straightening the angle to the corner. Was anybody else surprised by the amount and direction of curve on this shot?
I think what is going on is a gyroscopic effect. When an object is spinning about one axis while you turn it about a 2nd axis, the object picks up spin about the 3rd axis (perpendicular to the 1st and 2nd axes). For the kick shot, the sidespin is about the vertical axis, and the topspin picked up off the cushion is about a horizontal axis parallel to the cushion. The gyroscopic effect causes masse spin about an axis perpendicular to both of the other axes. That's what causes the curve. That's my "theory" anyway. What do the "science guys" (or others) out there think?
Regards,
Dave
PS: If you've never heard of or seen the "gyroscopic effect" before and are curious, there's lots of videos on YouTube, and the Wikipedia page also describes and illustrates it well.
I think what is going on is a gyroscopic effect. When an object is spinning about one axis while you turn it about a 2nd axis, the object picks up spin about the 3rd axis (perpendicular to the 1st and 2nd axes). For the kick shot, the sidespin is about the vertical axis, and the topspin picked up off the cushion is about a horizontal axis parallel to the cushion. The gyroscopic effect causes masse spin about an axis perpendicular to both of the other axes. That's what causes the curve. That's my "theory" anyway. What do the "science guys" (or others) out there think?
Regards,
Dave
PS: If you've never heard of or seen the "gyroscopic effect" before and are curious, there's lots of videos on YouTube, and the Wikipedia page also describes and illustrates it well.
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