That was the basis of my post, and the question I have. Is the progression linear? It certainly could be, but I wouldn’t assume so.
The best video of a Carbon Fiber shafts deflection testing with a robot arm
- Thread starter Mirza
- Start date
maybe the speed was to achieve the dent, or rather achieve a clearly visible dent for the viewers
i don't trust cue companies to do these tests anyway
i don't trust cue companies to do these tests anyway
snookered_again
Well-known member
It makes me wonder how far down the road a "mechanical opponent" is.
As long as the grip is in the same place for each shaft tested the pivot length does not matter in this type of tests. You want consistency in the data not tuning for a specific result.
L.S. Dennis
Well-known member
I came away with some of the same thoughts, why was the center ball hit mark different on the different shot was one thing for sure.
But I will say that on the whole, the Flowers shafts are most likely every bit as good as the Revos, ignites or any other one on the market and something like $100 dollars cheaper. So I suppose if someone wanted to pay that extra money to have one of the other name brands carbon fiber shafts that's up to the person I guess. I don't think there's a whole lot of difference between them when it comes to shooting balls into pockets on a pool table.
i don't know but here's a hint:
that was 3 years ago, since it's self-learning it will be even better now
Something is off on that test, I played with every shaft they are testing and the Ignite and Revo have quite a bit less deflection than the Cuetec.
Second thing, why is the cueball not spinning? Seems a bit odd, at the speed and side spin they use, even after hitting the backboard it should be spinning on the table.
Second thing, why is the cueball not spinning? Seems a bit odd, at the speed and side spin they use, even after hitting the backboard it should be spinning on the table.
Same as a normal shaft, different tapers, construction, ferrule design, end mass design. Not all the CF shafts are wound the same or formed the same.
In my experience, there is actually quite a difference between some of the CF shafts in the way they feel, sound, and perform. I currently own Predator Revos, Meucci Carbon Pro, Mezz Ignite, and Jacoby Black and I've had a McDermott Defy in the past and I can tell you that they vary greatly between them. Again, only IMHO.
To be honest though. As much as we could nitpick their methods and compare them to normal operating conditions, it does still appear the results are likely within the ballpark. It's not like it determined there was no difference. Or determined Cuetec has less deflection than Predator. It kinda reinforces what we already know to be true from experience and other tests. It gives "one more measure" in terms of quantifying the differences in the deflection profiles of these shafts and it may be reliable enough in terms of informing your purchase decisions if you had a sense of what kind of deflection profile you're seeking. Fully minimize deflection? Willing to accept some deflection for a little more feel? Wanting to try something similar to a Revo but another brand?
Several pool playing robots have already been developed. Here is one that seems to have been developed in a very short time by students who already had a robot and some other software. This was done 13 years a go.
I think the test was reasonably well done but I can see a few potential problems.
As far as the speed went, I think it was very high to avoid the ball curving back with swerve and cancelling some of the deflection. I think they could have avoided the swerve by having the cue stick exactly level. It looked like the end rail was still on the table so it was not possible for the stick to be completely level. Take the end rail off.
Like others, I'm worried about the center ball hits not going to the same place. Notice that the small plate the ball is positioned by is not connected to the main part of the robot. It's just sitting on the cloth. It looks like they got the alignment by a laser. The differences look like a few millimeters but that is comparable to some of their measured differences.
They don't measure the side spin on the cue ball. I think it's important to know the spin (along with the speed) so you know that you are hitting equally far from center in all cases. Some tips might be harder, rounder, etc. which can change the effective amount of spin. A flatter tip will appear to deflect less because it will hit closer to the center of the ball.
The way the cue stick is held might be a big problem. In 1998 several people including me, Mike Shamos, and Jim Buss did some testing with Predator's testing robot "Iron Willie". Willie had a rather heavy arm that held onto the cue stick. That arm was clamped tightly to the butt for repeatability. That turned out to be a large problem because the weight of the stick was increased by the weight of the clamped part. Maybe it was 40 or 50 ounces. That meant that the cue stick did not slow down as much as it normally would when hitting the ball. For no spin that's sort of OK, but for a lot of spin the stick needs to slow down so it doesn't drag on the side of the ball at the end of contact.
A second problem that Willie had that the new experiment seems to have avoided is the bridge hand. If it is very solid and close to the tip, it can increase deflection a lot. The bridge thing seems to be back a long way which eliminates its effect. Predator has since redesigned Willie to be more human in how he holds the stick.
I think they should have done both left and right side spin for all cases. That could show the problem with centering as the center spot would not be right between the two side spin spots.
As far as the speed went, I think it was very high to avoid the ball curving back with swerve and cancelling some of the deflection. I think they could have avoided the swerve by having the cue stick exactly level. It looked like the end rail was still on the table so it was not possible for the stick to be completely level. Take the end rail off.
Like others, I'm worried about the center ball hits not going to the same place. Notice that the small plate the ball is positioned by is not connected to the main part of the robot. It's just sitting on the cloth. It looks like they got the alignment by a laser. The differences look like a few millimeters but that is comparable to some of their measured differences.
They don't measure the side spin on the cue ball. I think it's important to know the spin (along with the speed) so you know that you are hitting equally far from center in all cases. Some tips might be harder, rounder, etc. which can change the effective amount of spin. A flatter tip will appear to deflect less because it will hit closer to the center of the ball.
The way the cue stick is held might be a big problem. In 1998 several people including me, Mike Shamos, and Jim Buss did some testing with Predator's testing robot "Iron Willie". Willie had a rather heavy arm that held onto the cue stick. That arm was clamped tightly to the butt for repeatability. That turned out to be a large problem because the weight of the stick was increased by the weight of the clamped part. Maybe it was 40 or 50 ounces. That meant that the cue stick did not slow down as much as it normally would when hitting the ball. For no spin that's sort of OK, but for a lot of spin the stick needs to slow down so it doesn't drag on the side of the ball at the end of contact.
A second problem that Willie had that the new experiment seems to have avoided is the bridge hand. If it is very solid and close to the tip, it can increase deflection a lot. The bridge thing seems to be back a long way which eliminates its effect. Predator has since redesigned Willie to be more human in how he holds the stick.
I think they should have done both left and right side spin for all cases. That could show the problem with centering as the center spot would not be right between the two side spin spots.
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One interesting result was the difference in speed of the various shafts. Maybe some of it was due to different tips, but the wood shaft was down about 15% on speed compared to CF. I assume they used the same stick speed setting for all shots, but it would have been good to measure that as well.
dquarasr
Registered
On the side spin shots I made an effort to look at closely, the cue ball was spinning quite quickly.
The machine uses TOI.
I think it's pretty clear at 6:11. Also, the ball always moves off to the left after hitting the backstop.
VTEC John
Active member
(You can change the speed of any youtube video by clicking the little gear wheel --watch at quarter speed, for example.) The "tee" the ball sits on is just sitting on the baize, with inked lines to position it. If you compare those lines at 4:35 to 7:02, either they have been redone or the tee has been intentionally moved about a half inch right. Also, that tee looks as though it would move a tiny bit at each launch and need to be tweaked back into position. Finally, at 5:24 you can actually see slight side-to-side movement of the cue's upper forearm. So that machine, which looks a bit homemade anyway, isn't locking the cue travel into a perfectly straight path. To me, these things explain the center ball discrepancies and probably invalidate the whole thing. An earnest effort, just inadequate.