LD and Power
- Thread starter Patrick Johnson
- Start date
Alright... I have a few moments to jot down what was spinning in my head this morning about this discussion.
If jumping is all about end mass, then in theory I should be able to drop a pool ball onto a CB and jump like a champ. Go ahead and try it, and post back your findings. It doesn't work worth a crap. Why...? because the dropping ball moves out of the way. The ball isn't flexible but there's nothing preventing it from moving off path other than it's own inertia. Now lets consider the Predator Air 2, that has a total weight of 10oz, double the weight of a pool ball. Let's wrongfully assume that the end mass of that jumper is half it's total weight. So I can jump with a cue that has an end mass of 5oz (realistically less) but can't with a pool ball that's 5oz.
The only difference I can see in the above comparison, is the rigidity of the jump cue. It's stiffness helps prevent a deviation from it's original path. Note I said "helps"... nothing is absolute. This refusal to "get out of the way" pinches the CB with greater force, resulting in the CB being ejected. (hopefully "ejected" rather than "squirt" make this easier to comprehend) A LD shaft, much like the dropping pool ball, can deflect away with greater ease, so rather the CB being "ejected" relative to the compound angle of the cue tip to slate, the shaft bends.
Here's a clip from Dr Dave showing a jump in slow mo. Note the near zero flex in the shaft. That's just not about endmass. Maybe if he stumbles into the this thread, he could perform the same shot with a LD shaft and we can note the differences.
So yes, LD shafts suck at jumping because of a bad transmission of energy. However that isn't due to end mass, but rather shaft flexibility. I could perform a jump shot with something heavy that was also very flexible and not get any elevation.
I have an original Pred 314 kicking around that I don't care about. If I can figure out a way to increase it's end mass without effectiing it's ability to flex, I've prove my theory.
In terms of jumping, rigidity is of greater value then end mass.
If jumping is all about end mass, then in theory I should be able to drop a pool ball onto a CB and jump like a champ. Go ahead and try it, and post back your findings. It doesn't work worth a crap. Why...? because the dropping ball moves out of the way. The ball isn't flexible but there's nothing preventing it from moving off path other than it's own inertia. Now lets consider the Predator Air 2, that has a total weight of 10oz, double the weight of a pool ball. Let's wrongfully assume that the end mass of that jumper is half it's total weight. So I can jump with a cue that has an end mass of 5oz (realistically less) but can't with a pool ball that's 5oz.
The only difference I can see in the above comparison, is the rigidity of the jump cue. It's stiffness helps prevent a deviation from it's original path. Note I said "helps"... nothing is absolute. This refusal to "get out of the way" pinches the CB with greater force, resulting in the CB being ejected. (hopefully "ejected" rather than "squirt" make this easier to comprehend) A LD shaft, much like the dropping pool ball, can deflect away with greater ease, so rather the CB being "ejected" relative to the compound angle of the cue tip to slate, the shaft bends.
Here's a clip from Dr Dave showing a jump in slow mo. Note the near zero flex in the shaft. That's just not about endmass. Maybe if he stumbles into the this thread, he could perform the same shot with a LD shaft and we can note the differences.
So yes, LD shafts suck at jumping because of a bad transmission of energy. However that isn't due to end mass, but rather shaft flexibility. I could perform a jump shot with something heavy that was also very flexible and not get any elevation.
I have an original Pred 314 kicking around that I don't care about. If I can figure out a way to increase it's end mass without effectiing it's ability to flex, I've prove my theory.
In terms of jumping, rigidity is of greater value then end mass.
The clip from Dr. Dave clearly shows the shaft moving out of the way of the rising CB.
Watch the shaft throughout it's length during the shot. Slow it down if need be.... The shaft does not bend. The whole length moves linear fashion. Most certainly pushing down on his bridge.
Here's another Dave slow mo vid, but this time he hit above the CB equator. Again you'll see the shaft length move in linear fashion due to the impact but it does not flex.
You really do need to slow the the playback to .25
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How then do you explain LD shafts that are stiff (like my conical taper LD shaft) but still jump poorly?
pj
chgo
That really boils down to what you believe to be "stiff". Unless there's some crazy unbiased means to test for that characteristic, then it's simply subjective opinion.
What I can tell you is.... I have 3 LD shafts. A Mezz wx700, and two predators (314 and Z2). The Mezz is way stiffer than the Z2. It also squirts the CB way more than the Z2. The Mezz total weight is ~4oz, and the 314 comes in at ~3.2oz (those weights found online). There is nothing to be gained in terms in jumping ability with that extra .8oz the Mezz has. Keep in mind the Mezz has a soft tip, which blows for jumping.
All three of those shafts can be bent when cupped by your fingers and pushed with your thumb. The Mezz and 314 are very simliar. Not very scientific I know, but I've got nothing else...lol. End mass has zero bearing on my ability to bend those shafts by hand, but yet they bend, and at greater amounts then solid shafts.
I'm kinda done running in circles. You didn't understand something and posted the question, I've done my best to explain what I believe to be true. Believe what you like, and please if you find something this disproves my opinion then post it. I don't have a problem being wrong, but it's takes more than someone just saying they don't think I'm right.
Has the stiffness of HD shafts been measured, or is that simply subjective opinion too? I'm guessing that, like me, you've owned and used both stiff and whippy cues and can tell the difference.
I think stiffness can be measured pretty easily with a little setup - in fact, some years ago one of the big name cue makers used a pretty simple stiffness testing contraption at tournaments and shows to demonstrate the "radial consistency" of their shafts.
pj
chgo
Sounds like a PR response. So is it the light front end not impartng energy (force) or the the fact it gets out of the way too qucikly and the force is being comsumed by what it takes to flex the shaft...?
I buy that, so far as it goes. But I wonder if lower end mass also comes with a structural difference that reduces power transfer. For example, does it compress more longitudinally, absorbing more of the force? Or does it impede a longitudinal "shock wave" so that less of the cue's mass is involved in the collision?
pj
chgo
Curious... are you thinking that shaft compression is the more likely cause for poor jumping performance then shaft deflection...?
How can players manage to hit such powerful breaks with LD shafts if their structure is inherent to poor power transfer...?
FWIW I asked Dr Dave in his latest slow mo thread about potentially doing a super slow mo vid of a LD jump attempt. I added that my take on their short coming is due to flex more so the end mass....
Here is his response...
Here is his response...
I'm wondering what the mix of causes is (between end mass, stiffness and other structural differences) and how important each is to the outcome.
Fair question - if they're comparably powerful to HD shafts. Do we know that?
pj
chgo
Well the point of low end mass is to lower inertia, which aids in allowing the shaft to deflect. However if you a had very low end mass shaft that was still extremely rigid. The shaft wouldn't "get out of the way" after contact (it needs to flex) and the CB woud still squirt as it would with a standard solid shaft. Without flexibility you can't have a LD shaft. The whole concept revolves on the cue deflecting rather than the ball.
Fair question.... It could be merely marketing hype for all I know. I don't hit LD breakers well. I cannot generate the necessary cue speed along with a square hit to benefit from them. All I can say is that the big breakers I know, break bigger with LD breakers.
We've been around this block. Sorry, but I still accept Dr. Dave's conclusion (supported by other knowledgeable folks and my limited experience) that squirt is primarily about end mass.
pj
chgo
yep we have.... squirt in the world of pool is the result of an object forcing itself into space occupied by a 2nd object while following an off axis trajectory to said 2nd object. The rest, including Dave's take, are the factors relative to how much squirt can be expected / controlled.
You may use different wording but you're still fixated on this definition of squirt and what Dave says are the factors of producing it. That's why I coined "ejected" when describing the process of jumping a ball. As you can't seem to look beyond what you preceive as squirt. If you truly want to understand why the CB can be jumped and why LD shafts suck at it, you'd be better off dismissing squirt as something related to jumping a ball.
Really, now that I read my first paragraph over. The only difference in practice between a normal shot that would develop squirt and a jump shot, is the addition of an immovable object (table surface) that would prevent the normal trajectory of the 2nd object when the 1st object enters it's space.
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You can clearly see the shaft deflect above the rising CB. You can also see the whipping up and down afterwards--implying the shaft bent during contact.
I don't agree with you think you're seeing. I won't argue against your opinion. I will just add that nothing is 100% rigid, so some deflection would occur regardless of shaft type. The point is a LD shaft is more flexible than a solid maple, or a hollow shaft loaded with a rigid material. That's what makes them bad for jumping.
Hopefully Dr Dave may get the chance to hit a LD shaft in the same manner in super slow mo, and we'll have something to compare against.
I ran through the thread again incase you had stated it prior, but couldn't find any mention of the maker/model of your LD shaft.
Curious if I have a local player that may have the same type so I can compare with what I have on hand.