User Tag List

Page 4 of 14 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 13 14 LastLast
Results 52 to 68 of 234
  1. #52
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    Quote Originally Posted by kwun View Post
    i have to disagree. the head will exand and contract under heat/cold and result in a bigger/smaller oval.
    You're correct.

    Coefficient of linear thermal expansion of pure graphite is 4.4 x 10^-6 in/inF, and for aluminum is 12.3.

    So for 15C change is 27F change. Plug in 27 in for frame circumference.
    Results in 0.0032 in, or 0.081 mm.
    Somehow that is very negligible.

  2. #53
    Administrator kwun's Avatar
    Join Date
    Apr 2002
    Location
    Santa Clara, California, United States
    Posts
    36,155
    Mentioned
    55 Post(s)
    Tagged
    2 Thread(s)

    Default

    Quote Originally Posted by visor View Post
    You're correct.

    Coefficient of linear thermal expansion of pure graphite is 4.4 x 10^-6 in/inF, and for aluminum is 12.3.

    So for 15C change is 27F change. Plug in 27 in for frame circumference.
    Results in 0.0032 in, or 0.081 mm.
    Somehow that is very negligible.
    hehe. so there IS!!

    i agree though, it is negligible.

    but how do we explain your observation then?

  3. #54
    Moderator cobalt's Avatar
    Join Date
    Aug 2010
    Location
    Arrakis
    Posts
    8,905
    Mentioned
    44 Post(s)
    Tagged
    1 Thread(s)

    Default

    Quote Originally Posted by visor View Post
    You're correct.

    Coefficient of linear thermal expansion of pure graphite is 4.4 x 10^-6 in/inF, and for aluminum is 12.3.

    So for 15C change is 27F change. Plug in 27 in for frame circumference.
    Results in 0.0032 in, or 0.081 mm.
    Somehow that is very negligible.
    Have you tried it? Did you measure it with your electron microscope? Did you leave your favourite racquet out on the cold, cold mountain for a day, then slow-roasted it over the barbeque, and measured the difference?

    If everything in the real world could be explained through physics and theorems and stuff, we would all be visor than we are...

  4. #55
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    Lol! Lemme check the coefficient for cobalt and see if I need to subject it to extreme temps...

  5. #56
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    Quote Originally Posted by kwun 2049843
    hehe. so there IS!!

    i agree though, it is negligible.

    but how do we explain your observation then?
    I don't know... I'll check vs850 tonite.

  6. #57
    Administrator kwun's Avatar
    Join Date
    Apr 2002
    Location
    Santa Clara, California, United States
    Posts
    36,155
    Mentioned
    55 Post(s)
    Tagged
    2 Thread(s)

    Default

    2 rackets. NS9000, AT900P

    both strung with NBG98 @ 23.8/26lbs

    0hr:

    NS: 1212.3Hz
    AT: 1193.4Hz

    3 hrs:

    NS: 1188.4Hz
    AT: 1162.1Hz

    17hrs:

    NS: 1177.0Hz
    AT: 1150.4Hz

  7. #58
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    VS850 at 24 lb on SW30 from 9 months ago, rarely played

    1027 Hz at 20C
    1023 Hz at 5C
    1027 Hz at 20C again

    So, there is a trend. Tensions fall off a tad when colder. But this is only like 0.1 lb and the string material hardening with colder temp is probably more significant in causing a harder brittle feel in the cold.

    Still would be interesting to see what happens in Asia going from 20C to 35C. Anyone?

  8. #59
    Regular Member ucantseeme's Avatar
    Join Date
    Feb 2010
    Location
    @home
    Posts
    976
    Mentioned
    14 Post(s)
    Tagged
    0 Thread(s)

    Default

    Quote Originally Posted by ucantseeme View Post
    SW35 with BG80 @29lbs: 1197 Hz, strung @Yonex German Open with EsPro, measurement at 6-8 hours after stringjob.
    Today, at 1123 Hz. String and tension feel comfortable, powerful and are superb IMO.

  9. #60
    Regular Member
    Join Date
    Mar 2011
    Location
    Canada
    Posts
    341
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default

    Looking at a few frequencies provided and comparing, it seems to me like Victor racquets tend to have a lower frequency at the same tension as lets say Yonex. Could have to do with the fact that they don't fill the racquets with foam.

  10. #61
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    Quote Originally Posted by blableblibloblu View Post
    Looking at a few frequencies provided and comparing, it seems to me like Victor racquets tend to have a lower frequency at the same tension as lets say Yonex. Could have to do with the fact that they don't fill the racquets with foam.
    Hmmm... as I understand, the foam is placed inside the T joint, not throughout the whole frame, right? I don't think I've ever seen any foam in the frame in any of the broken rackets post mortem photos.

  11. #62
    Regular Member
    Join Date
    Mar 2011
    Location
    Canada
    Posts
    341
    Mentioned
    4 Post(s)
    Tagged
    0 Thread(s)

    Default

    Quote Originally Posted by visor View Post
    Hmmm... as I understand, the foam is placed inside the T joint, not throughout the whole frame, right? I don't think I've ever seen any foam in the frame in any of the broken rackets post mortem photos.
    http://bbs.badmintoncn.com/thread-196139-1-1.html
    not quite sure exactly where they put it since I haven't looked at the whole thread and haven't translated what he says. Doesn't seem to be in the whole frame though. Could still have an impact on frequency though, I think.

  12. #63
    Regular Member Mark A's Avatar
    Join Date
    Sep 2005
    Location
    St Helens, UK
    Posts
    4,723
    Mentioned
    27 Post(s)
    Tagged
    0 Thread(s)

    Default

    If anybody hasn't got an iPhone - I can't be the only one - there's a free program called PitchPerfect that does exactly the same thing on a PC. All you need is a microphone of some kind.

    Just tested a couple of strings against generated tones, and they sound spot on. Now I've got some kind of objective measure of tension loss, but this means I'm probably going to re-test everything. Thanks, OCD!

  13. #64
    Regular Member Mark A's Avatar
    Join Date
    Sep 2005
    Location
    St Helens, UK
    Posts
    4,723
    Mentioned
    27 Post(s)
    Tagged
    0 Thread(s)

    Default

    Interesting to see how much tension is lost early on... just tested the Adidas Power Tour 66, and it's gone from 1277 Hz to 1228 Hz in 12 hrs before it's even hit a shuttle! 3.8%, IOW.

    Looking forward to seeing the "fresh" frequency of Zymax 62 at 30x31...

  14. #65
    Regular Member msitpro's Avatar
    Join Date
    May 2012
    Location
    Ipswich, Suffolk, United Kingdom
    Posts
    219
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)

    Default

    Quote Originally Posted by Mark A View Post
    Interesting to see how much tension is lost early on... just tested the Adidas Power Tour 66, and it's gone from 1277 Hz to 1228 Hz in 12 hrs before it's even hit a shuttle! 3.8%, IOW.

    Looking forward to seeing the "fresh" frequency of Zymax 62 at 30x31...
    Mark, did you ever get a reading for ZM62 @ 30x31 ?

    Contribution:

    ZM65 @ 26x28 on NR700RP using crank machine tension tested with scales immediately before

    0hrs = 1189 Hz

  15. #66
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    As a reference, my ZM62 @22x23 lbs ECP :
    0hr = 1212 Hz

  16. #67
    Regular Member msitpro's Avatar
    Join Date
    May 2012
    Location
    Ipswich, Suffolk, United Kingdom
    Posts
    219
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)

    Default

    Quote Originally Posted by visor View Post
    As a reference, my ZM62 @22x23 lbs ECP :
    0hr = 1212 Hz
    That frequency looks more like 26 lbs based on other results in this thread?!

  17. #68
    Regular Member visor's Avatar
    Join Date
    Dec 2009
    Location
    Vancouver, BC
    Posts
    10,262
    Mentioned
    139 Post(s)
    Tagged
    1 Thread(s)

    Default

    Quote Originally Posted by msitpro View Post
    That frequency looks more like 26 lbs based on other results in this thread?!
    Yes, and that's the wonder of super thin strings.

Page 4 of 14 FirstFirst 1 2 3 4 5 6 7 8 9 10 11 12 13 14 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •