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  1. #52
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    Quote Originally Posted by craigandy View Post
    That's reeeaaly helpful. I am under no illusions that I must be missing something. What? is the question.
    I've already pointed out the logic error that people have been caught out by, trying to convert ALL the momentum/energy of the racket into the shuttle.

    Everyone is also missing the fact that throughout the swing, the player is accelerating the racket so the system of racket + shuttle that people are considering is subject to external forces that invalidate all the maths + conclusions.

  2. #53
    Regular Member visor's Avatar
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    But it doesn't matter what happens throughout the swing, it's exactly at that point of shuttle and racket contact that we're concerned about with either P or KE exchanged and hence their respective conservation equations... and I still prefer KE, as does Yonex apparently.
    Last edited by visor; 05-16-2013 at 06:55 PM.

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    use the equations here for v1 & v2.

    http://en.wikipedia.org/wiki/Elastic_collision

    I'm sure you can fiddle the shuttle and racket masses to make things seem plausible.

  4. #55
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    Quote Originally Posted by visor View Post
    But it doesn't matter what happens throughout the swing, it's at that point of shuttle and racket contact that we're concerned about with either P or KE equations... and I still prefer KE, as does Yonex apparently.
    both are equally valid. But you do need to know what you're doing before you star plugging numbers in to equations.

  5. #56
    Regular Member craigandy's Avatar
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    Quote Originally Posted by amleto View Post
    I've already pointed out the logic error that people have been caught out by, trying to convert ALL the momentum/energy of the racket into the shuttle.

    Everyone is also missing the fact that throughout the swing, the player is accelerating the racket so the system of racket + shuttle that people are considering is subject to external forces that invalidate all the maths + conclusions.
    Still not picking up what your putting down.
    I don't think anybody was trying to convert all momentum, just using what's available to get ball park figures. Friction,repulsion, absorpsion, etc can be subtracted after using either formula and affect it the same? I have not read anybody disagreeing with this or not getting it. What still remains is that the ke formula seems to give a good ball park figure but the momentum one doesn't.
    Last edited by craigandy; 05-16-2013 at 07:11 PM.

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    I'm getting a feeling that we're sidetracked...

    Pronation should help generate more power. However, as some have pointed out, panhandled grip would restrict the amount of rotation one can have.

    For the same reason, but with a completely different effect, panhandled grip would allow full supination to be applied without sending the shuttle outside the court. So even with overhead shots, panhandle works much better with backhand shots.

  7. #58
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    You can see Lin Dan use a slightly more panhandle grip when he clears as you can see his wrist flex at the end of the stroke.
    This is not something I've observed. If you have an example, I'd be interested to see it.


    Quote Originally Posted by Stratlover View Post
    While some people may teach shifting towards panhandle for smashing, I would not recommend it unless you are taking it lower and farther in front than you should be, resulting in more of a powerful drive than a smash.
    That's not the idea. The idea is to take your ideal contact point -- which is only slightly farther in front than a clear -- and adjust your grip just slightly to avoid slicing the shuttle. It is very subtle -- so subtle that it's extremely difficult to tell the difference when watching players, even if you have slow motion video.

    In order to hit with maximum power, you need to have a (roughly) neutral wrist at impact. That's why the contact point for a smash should be brought slightly in front of the contact point for a clear.

    If a smash uses the same contact point as a clear, you have to bend your wrist downwards (i.e. flex) in order to get the racket pointing down. Doing so loses power, and this is one reason that a behind-the-body stick smash is less powerful than a power smash.

    Of course, this lowers your contact point back to what it would have been in the first place, so you don't gain any height advantage in the end. And the difference in height between the contact point of a smash and a clear is minimal anyway: about an inch.

    Whenever the contact point changes, the grip should change (all other things being equal). This applies to every shot. On the forehand side, farther in front = more panhandle, farther behind = more thumb grip. On the backhand side, it's the opposite.

    Large changes in the contact point require large changes in the grip. Small changes in the contact point require small changes in the grip.


    Almost every professional player uses a grip more towards basic while smashing, again, in order to get the downwards angle.
    Certainly the grip is much, much closer to basic than panhandle. I'm not sure how you can tell exactly what grip the professional players are using -- we are talking about a very small difference.


    They prioritize high contact point over the shuttle being very in front of their body.
    Of course -- but the contact point is still not the same as a clear.


    For shifting towards panhandle when clearing, that's not necessary especially for attacking clears, but may help for high defensive ones.
    That's definitely the wrong way around.

    A punch clear is an example of a shot where the wrist can be used deceptively. You can start with a smash (or fast drop) contact point, and then bend back (extend) the wrist to angle the racket more upwards.

    This gives you the option of winding up for a smash, deliberately slowing down your swing so that your opponent thinks you're playing a drop shot, and then finishing with a punch clear.

    This means you're hitting with an extended wrist and a partial panhandle grip. This results in a significant loss of power, but that's okay because you're playing a shot that needs little power.
    Last edited by Gollum; 05-17-2013 at 05:13 AM.

  8. #59
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    Quote Originally Posted by craigandy View Post
    Still not picking up what your putting down.
    I don't think anybody was trying to convert all momentum, just using what's available to get ball park figures. Friction,repulsion, absorpsion, etc can be subtracted after using either formula and affect it the same? I have not read anybody disagreeing with this or not getting it. What still remains is that the ke formula seems to give a good ball park figure but the momentum one doesn't.
    I had a quick scan and couldn't see the KE calculations that give a good result (and that I haven't already pointed out as being wrong). Can you point me towards it? Thanks

    I don't think anybody was trying to convert all momentum,...
    That's what you did in post 35 and why the answer you get is so crazy.
    Last edited by amleto; 05-17-2013 at 08:03 AM.

  9. #60
    Regular Member craigandy's Avatar
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    Quote Originally Posted by amleto View Post
    I had a quick scan and couldn't see the KE calculations that give a good result (and that I haven't already pointed out as being wrong). Can you point me towards it? Thanks

    I don't think anybody was trying to convert all momentum,...
    That's what you did in post 35 and why the answer you get is so crazy.
    I said I used the equation for momentum but in no way did i think the figure would be even vaguely correct. I just know when you used the same figures in both equations momentum came out 360mph and as visor calculated 136mph using the ke equation. Also I posted a link to other ke calculations done. Now I would guess if I did a 50mph swing in real life the shuttle would probably go about 70mph?
    So i can see 360mph is a long way off 70mph but 136mph is not(I know you lose a lot of speed given other factors).
    I think you are getting the wrong end of the stick though. I can only assume I must have the maths way wrong, I am not disagreeing. I was just looking for some more informed answers since it was raised as an argument in this thread.

  10. #61
    Regular Member visor's Avatar
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    @Gollum

    Interesting point you make about the contact point and grip changes. I think we all non beginners do this instinctively without thinking during play. Once you have your correct basic stroke mechanics, you will automatically adjust your grip to control the angle of the racket face relative to contact point, where you are on court, and where you want to hit to.

    Which is more important: proper grip or proper stroke?
    I suppose this is like the chicken and egg question.

    Both are just as important because you can't have one without the other.
    Last edited by visor; 05-17-2013 at 10:54 AM.

  11. #62
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    Quote Originally Posted by craigandy View Post
    I said I used the equation for momentum but in no way did i think the figure would be even vaguely correct.I just know when you used the same figures in both equations momentum came out 360mph and as visor calculated 136mph using the ke equation. Also I posted a link to other ke calculations done. Now I would guess if I did a 50mph swing in real life the shuttle would probably go about 70mph?
    So i can see 360mph is a long way off 70mph but 136mph is not(I know you lose a lot of speed given other factors).
    I think you are getting the wrong end of the stick though. I can only assume I must have the maths way wrong, I am not disagreeing. I was just looking for some more informed answers since it was raised as an argument in this thread.
    I don't know how else to say, all of the calculations done here are not correct because they assume all of the energy/momentum from the racket goes into the shuttle. Some have seen that the answers are ridiculous when using the full racket mass so they think the solution is to pick a number at random (the mass of the racket head), and try again and see what comes out.

    It doesn't matter what numbers are picked, the problem that everyone seems intent on solving is the wrong one!

    I did point those interested in the correct direction by linking to the elastic collisions wiki page. No one cared to plug their numbers into the equations I suggested, though.

  12. #63
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    Quote Originally Posted by visor View Post
    Imo, we should use KE... because even Yonex uses KE, instead of P.
    LOL, And Yonex could be wrong..

  13. #64
    Regular Member visor's Avatar
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    Quote Originally Posted by Cheung View Post
    LOL, And Yonex could be wrong..
    Nah... with their r&d, I doubt that we know any better than them...

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    Someone with some free PhD time could do a finite elements simulation for that situation ;-)
    Paper? (Aerodynamics - p.53 http://tinyurl.com/b28x6em)

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  16. #67
    Regular Member craigandy's Avatar
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    Quote Originally Posted by amleto View Post
    I don't know how else to say
    Say it by showing me the proper calculations with numbers and an explanation along with it or wait untill someone else can. Thanks

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