Sensitivity of Power Draw Shots - Physics or Mechanics?
- Thread starter Dan White
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The reason the system works poorly is that the number of rpms the cueball loses in the last diamond of a stop shot depends on the time over that diamond, not the distance. A fast shot will lose less draw. Complicating the issue is that twice as many rpms will give you four times the cue ball travel, not twice.
Bottom line is that the system might give you the right tendency but if done exactly as described it will be very inaccurate.
I tried to describe that - Test 1 was max draw, Test 2 was about half max. Since 1 went long and 2 was a little short, I assume 2/3rds max would work from the 2 diamond distance.That’s pretty neat.
Were your stop shots made with max draw contact point on cueball? If you use the stroke speed needed with slight draw (conventional stop shot) that is too fast. A stop shot performed with max draw contact point will be slower than a typical stop shot. Maybe that is why you got more draw than expected. In other words, testing this diamond system requires max draw contact point on cueball for all stop and draw shots. Otherwise the speeds will be off. I am just curious because it works well for me.
From the 7 diamond distance, both max draw and half max draw came back long, so maybe 1/3rd max would work from the longer distance in VP.
So much depends on cloth and ball surface conditions that it’s tough to make comparisons.
And since theory predicts problematic results as you have found, my conclusion is that the system of visualizing a distant stop shot can help a little but is in no way accurate. I suspect for each situation there will be a tip height and speed and required draw that fulfills the system's predictions, but that's not much help.
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There are two competing forces on a draw shot because the forward movement of the cue ball/speed of shot/force of hit fights that lovely backspin. So for tough draw shots the challenge is how softly can you grip, stroke and hit to retain that lovely backspin?
Hint: If you're hitting your close in draw shots hard, when the object ball is far from the cue ball you're going to struggle. Do some progressive draw drills focusing on the softest possible strokes that will yield draw.
Hint: If you're hitting your close in draw shots hard, when the object ball is far from the cue ball you're going to struggle. Do some progressive draw drills focusing on the softest possible strokes that will yield draw.
Are you saying that for a given tip offset below CCB, hitting it softer will yield more draw than hitting it harder?
Oikawa
Well-known member
If I understood right, I assume he's referring to the well known fact that more can go wrong in your stroke when your motion becomes punchy or rushed. And that it can be a beneficial mental image for some to hit "softer", even if in reality you hit it at the same speed, thinking like that just gets rid of some bad habits in your stroke (e.g. rushing/punching), and the cue ball doesn't care about how you accelerate into it.
Of course that’s true. But he said this instead, which implies something else:
Oikawa
Well-known member
Oh yes, my bad, Maybe he's referring to the fact that at certain (fast) speeds, it is actually beneficial to not use maximum bottom if you want the most draw action. Don't remember the exact tip position, but it's not much, just a tiny bit above maximum bottom.
Has to do with the relationship between how much the cloth slows you down on the way to the OB, and how much extra spin you get from going lower on the CB.
Better I don't speculate further, rather just let him say what he meant.
Yes, power draws at a distant OB are more efficient at 0.4R below center vs at the 0.5R limit, because the tiny bit of extra spin you get going to 0.5R is overridden by the additional CB speed you get hitting it slightly higher, giving friction less time to act on the CB on its way to the OB.
Not only a given
I've had many students who've struggled with draw on fairly simple draw shots, and for years, improve greatly, by simply gripping more gently and hitting more softly.
Not just a tip offset but a CB-OB distance. Over a relatively short distance between CB and OB, for example, a soft touch will yield much better results for most amateurs than the old school "hit it harder, aim lower, snap your wrist, accelerate through". That's why I wrote that for longer, more challenging draw shots, you're looking to see how softly you can grip and stroke, not how hard you can add acceleration and force.
I've had many students who've struggled with draw on fairly simple draw shots, and for years, improve greatly, by simply gripping more gently and hitting more softly.
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