@cobalt I just started threads in the past week on stringbed frequency vs tension, and now head wt vs bp,... and you're asking why I didn't incorporate kickpoint also... dang this is a tough crowd to please! Reason is I play with pretty stiff rackets like mx80, mx70, precision pro, so at the moment kickpoints don't matter to me...
Well, I wouldn't want anyone thinking you're anything less than perfect in what you do! Besides, you asked....
That's cheating! Your research and theories must allow for all empirical data. All of a sudden, you've just been demoted to mere mortal, in my eyes....
Update Update from the latest visit, with bare wts and bare bp calculated. [TABLE="width: 500"] [TR] [TD][/TD] [TD][/TD] [/TR] [TR] [TD] [TABLE="class: grid, width: 500"] [TR] [TD]Arc FB [/TD] [TD]73.1g [/TD] [TD]32.6g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]301mm [/TD] [/TR] [TR] [TD]Arc 11 [/TD] [TD]86.8g [/TD] [TD]38.1g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]296mm [/TD] [/TR] [TR] [TD]MX70 [/TD] [TD]86.9g [/TD] [TD]38.7g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]301mm [/TD] [/TR] [TR] [TD]MXJJS 4u [/TD] [TD]84.6g [/TD] [TD]37.2g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]297mm [/TD] [/TR] [TR] [TD]BSLYD 4u [/TD] [TD]84.3g [/TD] [TD]36.3g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]291mm [/TD] [/TR] [TR] [TD]BSLYD 3u [/TD] [TD]90.1g [/TD] [TD]40.0g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]300mm [/TD] [/TR] [TR] [TD]TK8000 [/TD] [TD]89.4g [/TD] [TD]39.3g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]297mm [/TD] [/TR] [TR] [TD]NR700FX [/TD] [TD]83.7g [/TD] [TD]36,4g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]293mm [/TD] [/TR] [TR] [TD]NR700RP [/TD] [TD]88.4g [/TD] [TD]38.3g [/TD] [TD][/TD] [TD][/TD] [TD][/TD] [TD]292mm [/TD] [/TR] [/TABLE] [/TD] [TD][/TD] [/TR] [TR] [TD][/TD] [TD][/TD] [/TR] [/TABLE] Interesting notes: - dang that 3u bslyd is a beast! more so than tk8000. i had dry swings with all of the rackets and this one takes the cake in swing wt! could've passed for a training racket! - obviously arc fb felt like a fly swatter on dry swinging...
seriously though, your research is definitely a great contribution and will probably help out people who know what they're looking for, in at least 95% of cases. I would suggest (and pending Kwun's approval) that you should take this a step further and use it as one of the main criteria for racquet selection. Now, to assemble the other main criteria, and insert formulae as required, put it all together in one succinct post and sticky it! Generations of badminton fanatics will forever choose wisely because of visor. (sorry, can't stay too long on the straight-and-narrow! )
^^ Actually thinking about it, my ultimate goal is this: to identify and measure all the aspects of the racket and string system so that any player can choose the right one for his/her particular swing and play style, hand speed and power, etc. Just as for golf equipment customization, I think this is possible and long overdue for badminton.
...and you're the man who can do it! Grunts like me will do all we can to help, but you'll just have to supply the brains yourself, I'm afraid...
Noooo... I can't do this alone. I need others to help too. Calling [MENTION=1]kwun[/MENTION] This is for the sake of knowledge and the benefit of the badminton community at large.
this ARC FB with only 73.1 g, and BP at 301mm...isn't this the ultimate racket for XD? light weight and a monster for killer smash?
Visor, how does knowing head weight benefit players? For example, since in your data your BS 12 and your MX 80 head weights seems to be equal, the BS 12 must be more powerful then? (Due to it being more aerodynamic thus can be swung faster). Am I correct in assuming this?
There's only 0.2g difference, not significant. But even then, we have to talk about specific copies of rackets because there's variations. Not all mx80 or bs12 have those same specs. That's why I emphasizing the importance of bringing a scale and a ruler and measuring or calculating head wt of the rackets at the store when choosing a specific one that you prefer, instead of leaving it to chance.
Hi Visor, (head wt / total wt) = (bp / 675mm) Can you describe head weight - what does this value represent, the weight of what? ... or from where to where? If you string and grip your racket and then cut it with a saw at fulcrum point, remove the piece of handle and then weight the rest - that would be your swing weight. If you come up with a formula for that, you might get Nobel prize for physics.
@meteor Swing wt is a dynamic measurement on an expensive machine costing thousands afaik. There is no cutting of rackets or handles. But for my informally made up head wt, I wanted an easier (and cheaper!) method of measuring or estimating swing wt statically. If you look at the pics on page 1, you'll see how I do it. And when I analyzed the data, I saw the relationship in that equation. So yes, if you cut the racket at the bp and weigh the top half, that will be exactly the same as my measurement of head wt. Isn't math and physics wonderful?
It is wonderful for those who understand it... not me though ) Just to point out that the upper side of the bp weighs exactly half of the overall weight (as much as the other half below) it doesn't depict the head load at all. Also there is a problem with the weighing methodology you use: the handle/grip contributes too to the presumed "static head weight" or if the handle support is placed at fulcrum point, the handle segment below fulcrum counterweighs the reading.
@meteor Dang... I'm gonna have to make a diagram to explain this concept so that it's easier to grasp. @j4ckie IIRC, You're good with physics. Help me out here please. Am I making sense? And how can I make it easier to understand?
@visor Ya, the equation is correct. Simple mechanics, actually....what you do is basically to mount the racket on 2 bearings. Ideally, you do it at the ends and parallel to the ground. Mechanics (and common sense) suggest that the full weight of the racket has to be born by those two bearings, thus if you measure the weight on one, you know the weight on the other (=full weight - measured weight). The BP is now easily calculable: BP = ("visor's head wt" / full weight) * racket length (usually 675mm). Or, if you measured at the bottom instead of the head, BP = ( (full wt - bottom wt) / full wt) * racket length Please note that all "visor's head weight" does is unify weight and BP to form a somewhat more reliable reference. It does not and can not take into account a) the stiffness, which will influence how the racket feels on swinging, with softer shafts making the racket feel heavier as they allow the head to drag behind more and create a bigger moment of inertia, and b) the distribution of the weight, which will influence both how heavy it feels on swinging (with a more extreme distribution feeling heavier by [theoretically] up to 33% with the same wt and BP) and how solid/heavy it feels on contact with the shuttle (with a more extreme distribution allowing a more solid head and thus more solid/heavy impact feel). Hope this helps. PS: reading this thread, I have to add c) the "kickpoint", i.e. the flexing behavior of the shaft. A tapered shaft will behave differently depending on how it is tapered (thick bottom will result in a more rigid feel, less bending and lower torsional rigidity of the head, thin bottom will result in more bending and better torsional rigidity).
