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Post by greenmonster on Aug 8, 2014 19:17:53 GMT -5
...Also I would like to see more detailed information as to what is wrong with the math.... Did you read my posting with the quotes about needing 3 dynamic parameters? Here is what I posted Any serious discussion of the matching of clubs requires an understanding of the mechanical properties of a club described by its three dynamic parameters. These dynamic parameters determine how the club swings in the hands of the golfer........One of these dynamic parameters is the total mass M of the club. Another is the first moment, S, about the wrist-cock axis, which it taken here to be 5 in. from the grip end of the club. The third dynamic parameter is the second moment, of the moment of inertia, I, about the same axis.................. Thus for all clubs of a set to feel the same in identical swings, they must have all three dynamic parameters respectively the same. Frans yes I read it and thanks for capturing and posting again. I think my definition of details and yours differ a bit and that is where the disconnect is. The details to me would be to show the detailed math of what you have above and the MOI machine to compare side by side so we can see the differences. Is it your opinion since the MOI machine was not built using this math that the machine does not work? I don't disagree with what Jorgensen writes, but is this his theory or has it been proven? Basically asking if a set of clubs has been built to prove the math.
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Post by fransatfrance on Aug 9, 2014 4:36:17 GMT -5
Did you read my posting with the quotes about needing 3 dynamic parameters? Here is what I posted Frans yes I read it and thanks for capturing and posting again. I think my definition of details and yours differ a bit and that is where the disconnect is. The details to me would be to show the detailed math of what you have above and the MOI machine to compare side by side so we can see the differences. Is it your opinion since the MOI machine was not built using this math that the machine does not work? I don't disagree with what Jorgensen writes, but is this his theory or has it been proven? Basically asking if a set of clubs has been built to prove the math. I can only (maybe wrongly) assume that you did not read the book, otherwise you would know that the full math and explanation is available in the Technical Appendix (Section 1 and 2) You would then also know that indeed set of clubs were build by Jorgensen and that in fact several clubfitters are building clubs in line with his work. Somehow you also miss the point that, even though the MOI machine itself it's doing the correct measurement, that using MOI is only one of the three needed dynamical parameters to swing clubs with the same feel. So using math where "Feel ~ MOI" where it really should be "Feel ~ M + S + I" (where I = MOI) is what I call "using incorrect math"
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Post by greenmonster on Aug 9, 2014 8:23:01 GMT -5
Frans I have not read the book but intend to now.
I believe I understand your point. Correct me if I am wrong, but what you are saying is the Engineering math behind the MOI machine is incorrect because it has been stated that this creates the same feel swinging all clubs. Is that what your point is?
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Post by fransatfrance on Aug 9, 2014 18:49:19 GMT -5
Correct me if I am wrong, but what you are saying is the Engineering math behind the MOI machine is incorrect because it has been stated that this creates the same feel swinging all clubs. Is that what your point is? No, that is not what I'm saying. The math in the MOI machine is fine for measuring MOI around some arbitrary rotation axis. Just the claim that MOI is sufficient to claim that all clubs with the same MOI will swing\feel the same is non-sense/bad science/pseudo-science. However the claim that MOI matched clubs all swing\feel the same is THE unique selling point according to the MOI supporters. But I have already explained all this one page one and two of this thread in reply to posting from you (page 2) and posting from Richie (page 1) The second claim that the MOI machines rotation axis is the same as the swings rotation axis is the other non-sense/bad science/pseudo-science part of the claim made by MOI supporters.
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Post by greenmonster on Aug 9, 2014 20:15:05 GMT -5
Correct me if I am wrong, but what you are saying is the Engineering math behind the MOI machine is incorrect because it has been stated that this creates the same feel swinging all clubs. Is that what your point is? No, that is not what I'm saying. The math in the MOI machine is fine for measuring MOI around some arbitrary rotation axis. Just the claim that MOI is sufficient to claim that all clubs with the same MOI will swing\feel the same is non-sense/bad science/pseudo-science. However the claim that MOI matched clubs all swing\feel the same is THE unique selling point according to the MOI supporters. But I have already explained all this one page one and two of this thread in reply to posting from you (page 2) and posting from Richie (page 1) The second claim that the MOI machines rotation axis is the same as the swings rotation axis is the other non-sense/bad science/pseudo-science part of the claim made by MOI supporters. Ok so the machine math is not the issue. The statement by MOI supporters is incorrect in your opinion. By the way, that was what I thought your point was. I don't sell MOI on the basis that it is the same feel in every club or that it is the same as the swings rotational axis. The way I apply MOI in fitting and club building is far superior to SW builds. This has been my experience in the practical application of both processes.
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Post by fransatfrance on Aug 10, 2014 4:19:01 GMT -5
The statement by MOI supporters is incorrect in your opinion. That is not an opinion but plain simple physics... I don't sell MOI on the basis that it is the same feel in every club or that it is the same as the swings rotational axis. The way I apply MOI in fitting and club building is far superior to SW builds. Yes, I know by now after x times the same posting with no substance that you apply MOI because you believe(!) it is far superior to SW builds. You have posted nothing to explain that superiority then some observations related to impact dispersion. You would have had the same observation when changing the playing length of the club or switching to a shaft with a different balance point or using a different shaft weight. You claim that same swing\feel is not your reason for using it. I therefor assume that you disagree with the statement that MOI is needed to match clubs to the same swing\feel. So I will not ask you that swing axis question again. But I will ask you this: 1) Explain what you did to determine that MOI was the correct fitting parameter to be changed in order to improve impact dispersion excluding the other possible fitting parameters. 2) Explain how improving that impact dispersion as the primary objective improved swing consistency. And how you determined that. 3) Explain why certain clubs must have a different MOI then others in the set in order to be playable.
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Post by greenmonster on Aug 10, 2014 8:06:27 GMT -5
You said earlier that I should post in the fitting area of the forum on fitting info. I have been trying to stay on just the subject.
Come on Frans. Why should I answer all your questions when you have avoided any of mine on SW. If you want to dig deeper into SW & MOI I am willing to discuss it. When you will share some substance to prove SW is better than MOI. Then I will share my view.
Prove to me that SW is the better way to go and why?
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Post by fransatfrance on Aug 11, 2014 4:09:46 GMT -5
You continue to express the inability to read (or understand or remember) what I write. Which part of "MOI worse then SW because it's based on pseudo-science" did you not understand? I explained why MOI is pseudo-science because of the claims made. I explained that part in fine detail. There is noting more to explain so why did I not prove my point?
You also seem to miss the point that because you use MOI without including first moment and mass you are in fact using SW! With the only difference is that you build a sloping SW set and no a flat line SW set. And if you would have read my posting in page 1(page one!) you can see that I explained how you can build a better set without even going into a SW/MOI discussion!
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Post by greenmonster on Aug 11, 2014 8:06:11 GMT -5
You also seem to miss the point that because you use MOI without including first moment and mass you are in fact using SW! With the only difference is that you build a sloping SW set and no a flat line SW set. And if you would have read my posting in page 1(page one!) you can see that I explained how you can build a better set without even going into a SW/MOI discussion! Why so mad Frans. Your post is ok in the first page but it lacks some details in my opinion. You have in no way made your point to me that MOI is worse than SW. The quote above is interesting as you are making some assumptions and to say you already explained everything in that post is incorrect in my opinion. If it was all understood we would not be 6 pages deep into this subject. so do you build flat line SW sets or slope SW sets?
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Post by fransatfrance on Aug 11, 2014 12:59:26 GMT -5
Not mad, very disappointed that I have to remind you that certain answers are already given 6 pages ago in this thread. For non-scratch golfers I build flatline SW within same type of clubs. Each type (wedge, irons, fairway woods, hybrids, driver) are fitted independently. So a full bag fitting is +/-15 hours of work. Unless the golfer himself requests MOI flatline but will do it only after informing him about the pseudo-science background of MOI. For scratch or better I fit as many clubs individuality as needed. So no need to for any SW or MOI interpolation within club-types. The resulting line can have any shape. After the move to a new place that is currently taking place and the purchase of additional heads\shaft & connectors I will fit non-scratch player in three irons so the correct shape of the line can be determined. Because of new knowledge acquired will working on an other project (TOMI putter machine improvement, www.clubfitter.eu/tiki-view_blog_post.php?postId=5) I will have a swing axis measurement system ready before the start of the new golf season next year. I hope that those measurements will help to improve the club matching procedure and allow to gain more insight in the swing behavior caused by fitting parameters. The clubfitters here in Europe I talked to about MOI agree with me that MOI has nothing to offer that is better then SW, they will however still continue to sell MOI flatline sets as that is what the golfing public expects to get, making MOI nothing more then a sales trick\gimmick.
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Post by Richie3Jack on Aug 11, 2014 14:22:22 GMT -5
I talked to about MOI agree with me that MOI has nothing to offer that is better then SW, they will however still continue to sell MOI flatline sets as that is what the golfing public expects to get, making MOI nothing more then a sales trick\gimmick. What percentage of the golfing public expects MOI matching? I don't think it would even hit remotely close to 1%. 3JACK
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Post by fransatfrance on Aug 11, 2014 18:57:46 GMT -5
I talked to about MOI agree with me that MOI has nothing to offer that is better then SW, they will however still continue to sell MOI flatline sets as that is what the golfing public expects to get, making MOI nothing more then a sales trick\gimmick. What percentage of the golfing public expects MOI matching? I don't think it would even hit remotely close to 1%. 3JACK Let me improve the statement by extending the phrase "golfing public" into "golfing public searching for a fitting by an independent clubfitter".
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Post by golfbaka on Aug 12, 2014 3:52:55 GMT -5
By 'MOI flatline' do you mean that all clubs (wedges, irons, fairway woods, hybrids, driver) are built to the same MOI? If so, which club fitters are doing this?
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Post by greenmonster on Aug 12, 2014 3:53:23 GMT -5
I am only asking more questions because I needed a little more clarity. What you think was enough and clear was not enough for me.
Just to clarify in my statement below. This is not an argument or me proving who is right or wrong.
You know Frans everytime you post pseudo-science I laugh. That is a funny word to me.
I agree that each club types should be fitted independently. The way I look at it, you have tool set's and each tool set needs to be calibrated to the individual golfer. What interests me though is in the MOI process you are going to have different MOI numbers for each club type and this is the same with SW. But you seemed to discount the MOI method because the numbers would not be the same in each club type. Yet this is what you do in your SW builds. Just pointing this out and I agree with your method.
You mentioned in one of your previous post's about MOI being a SW slope. I could argue that the from the other side like I have been but when you measure club types that are built using the MOI method on a SW scale you usually have a progressive ascending slope. To me the MOI machine is more accurate and I can build tighter club spec's using it. The other thing is the way I build clubs its more difficult when measuring a slope on the SW scale. This is probably the most interesting part of your post for me. Doesn't a golfers swing axis have subtle changes with each club length? For instance a PW versus a Driver. This would lead me to believe you will be fitting every club one at a time. Definitely would like to hear more on this fitting system.
What I have experienced and my opinion is very few golfers know about MOI fitting and the golfers searching for a fitting by an independent club fitter are in the small minority when it comes to MOI fitting knowledge. Most of the golfers looking for fittings have some knowledge of SW. We could argue this back and forth but MOI is not a popular method in the overall golf club fitting world. But you also have to realize that most of the golfing community thinks that the local Golfsmith guys know what they are doing. Most of them have just enough knowledge to be dangerous.
Frans to call the MOI method a sales trick/gimmick is your opinion. You obviously have a disdain for the MOI method. You have voiced your opinion and I hear you loud and clear. I just don't agree with your opinion on the MOI method.
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Post by greenmonster on Aug 12, 2014 4:24:54 GMT -5
By 'MOI flatline' do you mean that all clubs (wedges, irons, fairway woods, hybrids, driver) are built to the same MOI? If so, which club fitters are doing this? Welcome to the party golfbaka.
I know of know fitters that fit all clubs to the same MOI number. Good question.
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