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Post by imperfectgolfer on Dec 9, 2012 10:44:30 GMT -5
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Post by imperfectgolfer on Dec 9, 2012 19:32:46 GMT -5
Greg wrote the following in the Jeffy-forum thread.
"eye opening is all I can say. There is definitely going to be some interesting data on the differences between what we see on camera and what the little orange box says."
Very interesting!
I certainly look forward to seeing the final results of the research-a-thon. I suspect that BM and the BM groupies are getting very anxious about the possibility of Jeffy producing any "evidence" that refutes the accuracy of their favorite orange device. Of course, one can easily anticipate in advance that MF will likely discount any "evidence" that he doesn't want to believe!
Jeff.
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Post by gmbtempe on Dec 10, 2012 10:02:58 GMT -5
Greg wrote the following in the Jeffy-forum thread. " eye opening is all I can say. There is definitely going to be some interesting data on the differences between what we see on camera and what the little orange box says." Very interesting! I certainly look forward to seeing the final results of the research-a-thon. I suspect that BM and the BM groupies are getting very anxious about the possibility of Jeffy producing any "evidence" that refutes the accuracy of their favorite orange device. Of course, one can easily anticipate in advance that MF will likely discount any "evidence" that he doesn't want to believe! Jeff. I am not an expert scientist so my observations are more general but it sure seemed like they went to great lengths to make sure they were obtaining as accurate of data as possible. The setups were verified before each shot was taken, club face was remarked after each shot, new balls were used every time, etc. Here is a pic of my driver The data from Trackman was a bit all over the place. Seemed most accurate with shots that were close to the "grid" I will call it, they were on target, fairly centered strikes. On shots though were the ball was mistruck, had a lot of curve, started well offline, which is most of America, I felt like the device was not providing accurate numbers. For example this long drive guy hit a huge pull hook, probably 150 yards left of the target (and about 325y long) and Tman said has like 75 yards left, no way! It also seemed to have a correlation back to the clubface data in those cases. But back to solid hits, which I drove it pretty good in terms of hitting many straight drivers. The numbers on club face just did not seem to match the camera, or the ball flight. There was one case in particular that sticks out. I hit a very nice push draw and trackman said my face was closed a couple degrees and path was slightly left, that ball should have pull hooked. On the camera it was a zero'd path and the face was ever so open, ball was just hit ever so slight of center. I would have thought that to be a push fade but this ball drew about 10 yards. So something is going on. For starters Tman had it completely wrong even to my untrained eye on the face and path. But more importantly there is more to the launch direction and curve of the ball than just "the ball flight laws". I am not sure Tman is accounting for all the factors of impact in their face calculations, in fact they cant be based on the photo evidence. Now I here about "well given centered hits" statement with Tman and if thats the case, that a perfect centered hit must be achieved to have accurate data then I am not sure the device has any real usefulness other than a very advanced ball radar for distance, spin, etc. They also tested my drivers for launch angle and AofA at impact. On camera I was less down that Trackman was saying (3 to5 degrees on Tman if my memory is correct). The photos it was closer to 1-2 degrees. This is all from my memory, during testing, so I need to see the numbers but thats how I recall it.
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Post by imperfectgolfer on Dec 10, 2012 10:21:21 GMT -5
Greg,
Thanks for providing your perspective. It would not surprise me if the research-a-thon demonstrates that Trackman is only accurate for sweetspot hits where there is little divergence between the clubface angle and the clubhead path. I was always suspicious of Fred Tuxen's claims regarding how much the spin axis would be affected for each dimple of off-center hit - when the Trackman device cannot even see the clubface orientation angle. I am much more likely to trust direct visual evidence from the Phantom camera system when it comes to clubhead path and clubface orientation angle at impact. I am curious about one point - how does the Phantom camera research-a-thon enterprise deal with variations in clubhead attack angle if there is no additional Phantom camera mounted in the horizontal plane?
Jeff.
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Post by gmbtempe on Dec 10, 2012 10:54:43 GMT -5
Well in an ideal world you would have two cameras so you could get pictures of both at the same time rather than two different swings. I think that was a limitation this time around.
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Post by tapiosantala on Dec 10, 2012 11:32:58 GMT -5
This will produce lot of discussion... what about if all those things they have told are wrong?
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Post by tomdavis76 on Dec 10, 2012 11:38:53 GMT -5
Greg, Thanks for providing your perspective. It would not surprise me if the research-a-thon demonstrates that Trackman is only accurate for sweetspot hits where there is little divergence between the clubface angle and the clubhead path. I was always suspicious of Fred Tuxen's claims regarding how much the spin axis would be affected for each dimple of off-center hit - when the Trackman device cannot even see the clubface orientation angle. I am much more likely to trust direct visual evidence from the Phantom camera system when it comes to clubhead path and clubface orientation angle at impact. I am curious about one point - how does the Phantom camera research-a-thon enterprise deal with variations in clubhead attack angle if there is no additional Phantom camera mounted in the horizontal plane?Jeff. We couldn't on the same swing because we only had one camera. The ideal setup would be two synchronized Phantoms and a Trackman or Flightscope. We did reset the camera and shoot video from horizontal for many players so we do have data to evaluate's Trackman's accuracy on angle of attack, launch angle and dynamic lost. In one extreme case, Trackman reported dynamic loft of 9.5 degrees and the Phantom should dynamic loft of 18 degrees! BTW, the Trackman is VERY helpful with ballflight data, in particular carry distance, smash factor and spin rate. We were able to tweak setup and the tee height and help players pickup substantial yardage. Jeff
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Post by imperfectgolfer on Dec 10, 2012 11:51:22 GMT -5
Jeffy,
I am glad that you mounted the Phantom camera horizontally to test the accuracy of Trackman's angle-of-attack measurments.
I congratulate you and KM on undertaking this research-a-thon, and I look forward to reviewing your in-depth results/conclusions.
Jeff.
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Post by virtuoso on Dec 10, 2012 15:59:53 GMT -5
Was the balance point (cg) on the face measured/marked? This is not to be confused with the geometric center of the face. The geometric center is essentially useless.
Easy to find the balance point, but you have to have a driver with a detachable shaft. The drivers with glued in shafts would not have worked for defining head rotation on mis-hits if you couldn't define the balance point.
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Post by gmbtempe on Dec 10, 2012 16:07:05 GMT -5
Was the balance point (cg) on the face measured/marked? This is not to be confused with the geometric center of the face. The geometric center is essentially useless. Easy to find the balance point, but you have to have a driver with a detachable shaft. The drivers with glued in shafts would not have worked for defining head rotation on mis-hits if you couldn't define the balance point. I have never had a teacher use Trackman in a lesson, is this something they do as well in order to quantify the data they are teaching from? Is it built into the data, like you enter the specs of your clubs and it factors them into the data that is produced?
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Post by tomdavis76 on Dec 10, 2012 16:29:24 GMT -5
Was the balance point (cg) on the face measured/marked? This is not to be confused with the geometric center of the face. The geometric center is essentially useless. Easy to find the balance point, but you have to have a driver with a detachable shaft. The drivers with glued in shafts would not have worked for defining head rotation on mis-hits if you couldn't define the balance point. We were set up to do that but virtually no one had a detachable head. BTW, statements like the "geometric center is essentially useless" are essentially idiotic. We have tested several detachable heads and the variance from geometric center is always quite small, like a quarter-inch, typically towards the heel. Clubmakers aren't building clubs with the COG way off of center. Also, geometric center is needed to determine the contribution of bulge and roll to face angle and dynamic loft, respectively, on off-center hits. So marking geometric center and measuring the distance from there of the point of impact is essential. Anyhow, tracking the face angle with ProAnalyst easily shows face deflection on an off-center hit, so we know when one occurs without even looking at the point of impact. Jeff
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Post by cwdlaw223 on Dec 10, 2012 17:17:54 GMT -5
Jeff -
Did you measure or calculate face angle? For your preliminary findings of course since you indicated it will take months to sort through the data. Just wanted to confirm since Trackman calculates face angle as you've correctly mentioned in the past and the face behind the ball cannot be seen. I don't want to presume anything about your research/findings.
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Post by imperfectgolfer on Dec 10, 2012 18:11:04 GMT -5
Virtuoso wrote-: "Was the balance point (cg) on the face measured/marked? This is not to be confused with the geometric center of the face. The geometric center is essentially useless."
Why is the balance point of the COG important? I presume that it relates to the gear-effect behaviour of the clubhead in response to off-center shots, but I have never read a coherent explanation.
Jeff.
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Post by virtuoso on Dec 10, 2012 18:42:28 GMT -5
Was the balance point (cg) on the face measured/marked? This is not to be confused with the geometric center of the face. The geometric center is essentially useless. Easy to find the balance point, but you have to have a driver with a detachable shaft. The drivers with glued in shafts would not have worked for defining head rotation on mis-hits if you couldn't define the balance point. We were set up to do that but virtually no one had a detachable head. BTW, statements like the "geometric center is essentially useless" are essentially idiotic. We have tested several detachable heads and the variance from geometric center is always quite small, like a quarter-inch, typically towards the heel. Clubmakers aren't building clubs with the COG way off of center. Also, geometric center is needed to determine the contribution of bulge and roll to face angle and dynamic loft, respectively, on off-center hits. So marking geometric center and measuring the distance from there of the point of impact is essential. Anyhow, tracking the face angle with ProAnalyst easily shows face deflection on an off-center hit, so we know when one occurs without even looking at the point of impact. Jeff I apologize, I should have been more clear. Marking the geometric center is essentailly useless if you are trying to determine if the ball was struck on the exact sweet spot. If your contention is that closure rate has an influence on deflection, and you're also saying that deflection itself tells us whether the ball was struck off center, well......do you see the problem? Wouldn't marking the cg allow you to separate the variables?
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Post by tomdavis76 on Dec 10, 2012 19:03:56 GMT -5
We were set up to do that but virtually no one had a detachable head. BTW, statements like the "geometric center is essentially useless" are essentially idiotic. We have tested several detachable heads and the variance from geometric center is always quite small, like a quarter-inch, typically towards the heel. Clubmakers aren't building clubs with the COG way off of center. Also, geometric center is needed to determine the contribution of bulge and roll to face angle and dynamic loft, respectively, on off-center hits. So marking geometric center and measuring the distance from there of the point of impact is essential. Anyhow, tracking the face angle with ProAnalyst easily shows face deflection on an off-center hit, so we know when one occurs without even looking at the point of impact. Jeff I apologize, I should have been more clear. Marking the geometric center is essentailly useless if you are trying to determine if the ball was struck on the exact sweet spot. If your contention is that closure rate has an influence on deflection, and you're also saying that deflection itself tells us whether the ball was struck off center, well......do you see the problem? Wouldn't marking the cg allow you to separate the variables?Of course, marking the CG would have been preferable; I was shocked that virtually no one had a detachable head. We spent a lot of time preparing to balance and mark heads. As the team discussed it the other night at dinner, the ideal setup would be two synchronized Phantoms, a Trackman or a Flightscope (for ballflight data) and a bunch of interchangeable shafts and heads from the major OEMs, all with the CG marked, and mix and match the shafts and heads to find a combo the player liked. Then test off of that. Also, force plates, if only to keep players from digging holes in the turf from standing in the same place since we maintain a constant teeing position. Maybe if we get some OEM club manufacturer sponsorship...
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