Back to Forum
Page 1 of 4 1234 LastLast
Results 1 to 20 of 67
  1. UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 16,072 14,578
    UpSideDownCarl's Avatar
    UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 14,578 16,072
    #1

    Dwell Time and Throw Angle: Are These Terms Even Useful

    I just figured that, if there was a thread with this title it would not take very long before BrokenBall came on the thread and start giving people an earful. So, why not. Peter, I want you to do your best job at explaining as much as possible about Dwell Time and Throw Angle, what they are, what they are not.

    Also, feel free to post your video footage of how slow a blade flexes on impact and why impact rebound from a table tennis blade cannot possibly add a trampoline effect to the ball to add speed.

    Have at it.

    The Following User Likes UpSideDownCarl's Post:

    Lazer


  2. Gozo is offline
    says May the Spin be with you!
     
    Advanced TTD Member 134 266
    Gozo's Avatar
    Gozo is offline
    says May the Spin be with you!
     
    Advanced TTD Member 266 134
    #2
    Quote Originally Posted by UpSideDownCarl
    I just figured that, if there was a thread with this title it would not take very long before BrokenBall came on the thread and start giving people an earful. So, why not. Peter, I want you to do your best job at explaining as much as possible about Dwell Time and Throw Angle, what they are, what they are not.

    Also, feel free to post your video footage of how slow a blade flexes on impact and why impact rebound from a table tennis blade cannot possibly add a trampoline effect to the ball to add speed.

    Have at it.

    If I may add, please, pretty please explain in language even a grandmother can understand. Not all of us are engineers / scientist / astro-physicist etc. Thank you.

    The Following User Likes Gozo's Post:

    Attitude


  3. brokenball is offline
    This user has no status.
     
    This user has been banned. 425 948
    B
    brokenball is offline
    This user has no status.
     
    This user has been banned. 948 425

    User Info Menu

    #3
    One of the first TT documents I came across was this one below. I got it off the ITTF website. I haven't been able to find it on the ITTF website for years now but I have many terabytes of stored data.
    Notice the second short paragraph on the first page. It talks about the mysticism of TT and how hard it is to talk about reality. This was very true. It was hard to explain reality to hard headed idiots on mytt.
    I posted a link to this document many times and it was ignored. I would make fun of the people on mytt by asking them to define throw angle. No one could and people couldn't even agree on whether a rubber had high or low throw angle. It was fun trolling them. Yes, I am bad by making fun of the ignorance and pointing it out. On mytt they preferred to burn, ban me , the heretic rather than simply try to understand .
    The document talks about the normal and tangential coefficient of restitution and how it changes with impact speed. The basics of this document are still valid but now the ball is a little bigger and harder than it was before. Supposedly the rubbers are a little faster too but the basics still apply.
    https://deltamotion.com/peter/TableT...-%20Impact.pdf

    TT players tend to make up terms for things they don't understand. Throw angle is one of them. The last year I have seen more people talk about spin to speed but both can be related to the normal and tangential coefficient of restitution. It is best to use the ratio of the tangential coefficient of restitution to the normal coefficient of restitution instead of throw angle. Tests should not include humans as they are not calibrated.
    Read the document. I can explain.

    Dwell time is harder to explain and has many more myths and misconceptions. Going way back there was a forum member on mytt that called himself Anton Chigurh ( from the movie ). His thread was called "obscure question", It was about dwell time. Again, people couldn't define dwell time and that made talking to the hard headed idiots difficult. The problem is that many were trying to call dwell time as what they felt. I was trying to explain it is actual contact time. Because there were two definitions there was a lot of disagreement, hate, and discontent. I would make fun of the "touchy feelly" people. That included Baal at first. Baal did say that by the time the nerve pulses reached the brain the ball was long gone.
    I admit, I had lots of fun trolling the "touchy feely" people. Eventually Baal came around and did that he called his "napkin" calculations. It was crude but it was in the ball park. Baal was the ONLY person that even tried to estimate the true contact time. I had a lot of contempt for all those so called PhDs that did nothing but hide. The problem with Baal's calculation is that it assumed a linear deceleration until the ball stopped and a linear acceleration till the ball left the paddle. This isn't what happens. When the ball first makes contact with the rubber the rubber provides no resistance. Resistance increases as the ball penetrates the rubber. As resistance increases the ball decelerates at faster rates until all the kinetic energy is transformed into potential energy in the compressed rubber, ball and blade. Now comes the tricky part. The sponge, foam rubber has internal resistances or damping. Also, now that the sponge is compressed. The energy must now not only push the ball, it must accelerate the sponge fast enough to stay in contact with the ball. Simulating the impact part is easy. Simulating the rebound is not. It takes some assumptions.

    However, what is interesting is what what the peak force can be on the paddle during impact. Does anyone care to estimate?
    Another myth is accelerating through the ball. If the paddle is still accelerating then it isn't at maximum speed at contact.
    If the paddle is not at maximum speed at contact and accelerating past contact will only make recover time longer.
    Dwell time can be infinite. Normally is is quite short.
    On Anton's "obscure question" is posted a link to a video made by Tacshow123. I may have the spelling wrong. tacshow123 catches the ball on his paddle. In this case the dwell time is infinite. So what conditions are necessary to extend dwell time? I was banned on this forum when trying to show the answer. This forum never get an answer now, unless.

    Here is another questions. Let's assume you brush the ball and the ball deforms or stretches the rubber 0.1mm. If the dwell time is 1 ms then let's assume it takes 0.5 ms for the rubber to be stretched and 0.5 ms to rebound, then the rubber will cause a tangential motion of 0.1mm in 0.5 ms to help spin the ball. So what of the dwell time is shorter by half. Then the rubber will rebound .1mm in 0.25ms which is twice as fast for even more spin. So is longer contact/dwell time better?

    What I have found disturbing over the years is that even those with PhDs hide.

    Eventually, the engineers will find a way to make a robot that can move with the grace and speed of a human. The math and physics already exists to beat the best in the world. The limitation is the mechanics.




















  4. lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 244 703
    L
    lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 703 244
    #4
    well i ain't sure if I can use this kind of language here but i shall give it a try:

    """""Fer ****s sake .... not again !!! """ 不不不

    The Following User Likes lodro's Post:

    UpSideDownCarl


  5. brokenball is offline
    This user has no status.
     
    This user has been banned. 425 948
    B
    brokenball is offline
    This user has no status.
     
    This user has been banned. 948 425

    User Info Menu

    #5
    Quote Originally Posted by lodro
    well i ain't sure if I can use this kind of language here but i shall give it a try:

    """""Fer ****s sake .... not again !!! """ 不不不
    That is what I think when some one mentions throw angle and dwell time.
    Yeah, lets ban the words "throw angle" and "dwell time". Let the topics die.
    At least the myths will not be spread. No one can define them or truly understand them.

    Wouldn't you like to hear about the astronaut and trampoline? Oh well. I am done then.

    The Following User Likes brokenball's Post:

    lodro


  6. UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 16,072 14,578
    UpSideDownCarl's Avatar
    UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 14,578 16,072
    #6
    brokenball;354592
    I admit, I had lots of fun trolling the "touchy feely" people.
    Interesting. Some of the time he does know he is trolling.

    brokenball;354592
    I was banned on this forum when trying to show the answer.
    You have been saying this for years and it is absolutely false. You were banned at a time when a thread where the subject was dwell time and you were pontificating. But the reason you were banned is that a whole bunch of people complained ABOUT YOU and it got to Dan and he read through your posts and saw you calling people "Idiot" and other insults in a majority of those posts. So Dan decided he did not want someone on the forum whose main activity was to insult people. The only content that had anything to do with you getting banned was your fondness for insulting people.

    brokenball;354592
    What I have found disturbing over the years is that even those with PhDs hide.
    What I would ask is: why would any intelligent person want to discuss....debate....converse....argue....with someone who behaves the way you behave? Your behavior is generally lacking.

    Your "facts" are never the problem. Although you often argue that people said something they did not say. Just like you still are trying to insist you got banned for technical information when you got banned for behaving atrociously and insulting people and it had nothing to do with the technical information. The problem is you twist things and present that people said things they didn't and back before you got banned you were quite frequently in the habit of insulting people with names like "idiot".

    But anyone with better sense would not bother discussing technical issues with you because of how you behave.

    So, why am I doing this? I know this is a lost cause but I may as well call things how I see them. When people don't respond to your silliness, it is likely because they realize you have something going on that causes discussion to be a lost cause. You are not someone who discusses things. You set up a scenario where you can only be right and argue and the people who fall into that trap have not understood what you are doing. You are just trying to tell people they are wrong. Is there any other goal? I am not so sure. The facts you present are simple. You do know what you are talking about. The engineering, the physics, you do know what you are talking about. But you do not know how to communicate. And it seems that your goal is more in line with putting other people down rather than anything else.

    Perhaps this is why, in the post above, you spend so much time talking about people you have trolled, insulted and laughed at in the past. Odd to see an adult act in such an immature manner though.

    The Following 2 Users Like UpSideDownCarl's Post:

    JustANoob and wheelbuilder

    Setup 1: Blade by Nate: Vortex Spin Machine, FH Evolution MX-K, BH Evolution FX-P
    Setup 2: OSP Virtuoso Plus, FH Rasanter R 48, BH Rasanter R 48
    Spin is Everything

  7. Attitude is offline
    This user has no status.
     
    Established TTD Member 49 115
    A
    Attitude is offline
    This user has no status.
     
    Established TTD Member 115 49
    #7
    Quote Originally Posted by Gozo

    If I may add, please, pretty please explain in language even a grandmother can understand. Not all of us are engineers / scientist / astro-physicist etc. Thank you.

    Well he certainly failed at that i suppose.
    Maybe Carl is right, and he is unable to propperly communicate.

    Nevertheless i would say that there is no need to think much about dwell time because this value doesnt give you much at all. It just maybe the reason for a certain amount of speed or spin. But if you have a comparisment anyway in terms of speed and spin, why bother with the dwell time.

    The throw angle on the other hand is a completely different story imo.


  8. lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 244 703
    L
    lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 703 244
    #8
    maybe throw angle and even more dwell times are so difficult to explain and "categorize" because they are more a feeling
    rather than something measurable.
    There s one thing throwing a ball against a stiff board and another completely, throwing it against a rubber- a blade- a hand -a grip- a wrist - an elbow---------
    ---------- and of course finally against a brain. (Not in my case, it would be bragging )

  9. Michael Zhuang is offline
    This user has no status.
     
    Advanced TTD Member 37 284
    M
    Michael Zhuang is offline
    This user has no status.
     
    Advanced TTD Member 284 37

    User Info Menu


    Aug 2021
    284
    37
    0
    Read 0 Reviews
    #9
    My shallow understanding is:

    Flexier (usually thinner) blade = more dwell time, slower speed, more spin, more control to execute variety of shots, higher arc or throw angle

    Stiffer (usually thicker) blade = less dwell time, higher speed, less spin, less control to execute shots, straighter arc or throw angle

    Please correct me if my understanding is off.


  10. lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 244 703
    L
    lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 703 244
    #10
    Quote Originally Posted by Michael Zhuang
    My shallow understanding is:

    Flexier (usually thinner) blade = more dwell time, slower speed, more spin, more control to execute variety of shots, higher arc or throw angle

    Stiffer (usually thicker) blade = less dwell time, higher speed, less spin, less control to execute shots, straighter arc or throw angle

    Please correct me if my understanding is off.

    Weeeeeell, what if you mix up a flexie-blade with a hard rubber and a stiff blade with a very soft rubber ?????


  11. brokenball is offline
    This user has no status.
     
    This user has been banned. 425 948
    B
    brokenball is offline
    This user has no status.
     
    This user has been banned. 948 425

    User Info Menu

    #11
    No astronaut and trampoline for you.
    So USDC, ten years from now they will still be talking about dwell time, throw angle, boosting, hard rubbers and heavier paddles. Nothing will be learned.
    I am just going to watch videos.
    I still want to see Andrea, the anti player, block short against a chopper.



  12. Brs is offline
    This user has no status.
     
    Senior TTD Member 711 667
    B
    Brs is offline
    This user has no status.
     
    Senior TTD Member 667 711

    User Info Menu


    Oct 2015
    Christmas Island
    667
    711
    1893
    Read 0 Reviews
    #12
    My even shallower understanding is: > 99% player, < 1% equipment.

    The Following User Likes Brs's Post:

    lodro


  13. DTopSpirit is offline
    This user has no status.
     
    TTD Member 303 73
    D
    DTopSpirit is offline
    This user has no status.
     
    TTD Member 73 303

    User Info Menu


    Aug 2015
    Australia
    73
    303
    792
    Read 0 Reviews
    #13
    Quote Originally Posted by Brs
    My even shallower understanding is: > 99% player, < 1% equipment.

    A quick video from a recent match supporting Brs's theory (edit: video comes up fine in the preview, but not in the actual post, can a mod fix it?) :

    [video=face]https://www.facebook.com/plugins/video.php?href=https://www.facebook.com/watch/?v=267317218652756&ref=sharing[/video]

    Last edited by DTopSpirit; 4 Weeks Ago at 07:00 AM.

  14. Der_Echte is offline
    says Grand Consultant to the Office of the Goon Squad
     
    Master TTD Member 11,140 10,944
    Der_Echte's Avatar
    Der_Echte is offline
    says Grand Consultant to the Office of the Goon Squad
     
    Master TTD Member 10,944 11,140

    User Info Menu

    #14
    Quote Originally Posted by DTopSpirit

    A quick video from a recent match supporting Brs's theory (edit: video comes up fine in the preview, but not in the actual post, can a mod fix it?) :

    [video=face]https://www.facebook.com/plugins/video.php?href=https://www.facebook.com/watch/?v=267317218652756&ref=sharing[/video]

    Yes, I see the vid on my quote. Hope it pops up on the post.

    https://www.facebook.com/plugins/vid...56&ref=sharing

    https://www.facebook.com/plugins/vid...56&ref=sharing
    Last edited by Der_Echte; 4 Weeks Ago at 11:01 AM.
    President, Korea Foreign Table Tennis Club. Hit us up on TTD or Facebook
    http://www.facebook.com/koreaforeignttc

    Janitor at NexyUSA TT Equipment Shop
    http://www.nexyusa.com

    View our Lame Nexy USA corporate FB page
    http://www.facebook.com/nexyusa

  15. langel is offline
    This user has no status.
     
    Master TTD Member 1,060 2,225
    L
    langel is offline
    This user has no status.
     
    Master TTD Member 2,225 1,060
    #15
    Quote Originally Posted by lodro

    Weeeeeell, what if you mix up a flexie-blade with a hard rubber and a stiff blade with a very soft rubber ?????

    Very flexy blade with hard rubbers would be very difficult, or even impossible to control, very sensitive to the incoming spin and with a very wide rebound angle.
    But some blades with some to mid flex may have good synergy with some harder rubbers. Flex is not linear to the force of impact, so it will depend on players style too.
    Stiffer blades with softer rubbers will have better control on passive play, blocks and bang-bang, less sensitive to the incoming spin and with tighter rebound angle.


  16. lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 244 703
    L
    lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 703 244
    #16
    Quote Originally Posted by langel

    Very flexy blade with hard rubbers would be very difficult, or even impossible to control, very sensitive to the incoming spin and with a very wide rebound angle.
    But some blades with some to mid flex may have good synergy with some harder rubbers. Flex is not linear to the force of impact, so it will depend on players style too.
    Stiffer blades with softer rubbers will have better control on passive play, blocks and bang-bang, less sensitive to the incoming spin and with tighter rebound angle.

    very interesting but here is my experience:
    I have a very flexy blade, Sanwey J7, it has some 61 seconds Eagle rubbers 1.5mm H40 no problemos for me to play with at all
    I also have a TPS BlockmanII stiff as a brick blade with double boosted H3 Neo 37 2.15 mm again no problemos for me to play.
    ???????????


  17. UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 16,072 14,578
    UpSideDownCarl's Avatar
    UpSideDownCarl is offline
    says I like to hit Heavy Topspin
     
    Super Moderator 14,578 16,072
    #17
    Quote Originally Posted by DTopSpirit

    A quick video from a recent match supporting Brs's theory (edit: video comes up fine in the preview, but not in the actual post, can a mod fix it?) :

    [video=face]https://www.facebook.com/plugins/video.php?href=https://www.facebook.com/watch/?v=267317218652756&ref=sharing[/video]


    There are a whole bunch of bugs on the site that need an IT person to fix. Now, why they are not being fixed or why they have not been fixed already, that I cannot answer. I tried to post. But, yeah. It did not ocme up.

    Last edited by UpSideDownCarl; 4 Weeks Ago at 12:13 PM.
    Setup 1: Blade by Nate: Vortex Spin Machine, FH Evolution MX-K, BH Evolution FX-P
    Setup 2: OSP Virtuoso Plus, FH Rasanter R 48, BH Rasanter R 48
    Spin is Everything

  18. zeio is offline
    says 敹怒皞霈頧
     
    This user has been banned. 8,038 5,826
    Z
    zeio is offline
    says 敹怒皞霈頧
     
    This user has been banned. 5,826 8,038

    User Info Menu


    Jan 2018
    PNG
    5,826
    8,038
    21309
    Read 0 Reviews
    #18
    Praise Kuba for that. He warned that the forum didn't escape HTML tags after the update and guess what? The admins reacted by escaping everything other than the VIDEO tag, probably out of laziness. That breaks everything. IMG tag that points to anything off-site is not parsed at all, so no images unless you upload them to TTD. We're very safe now but we're worse off.

    https://www.tabletennisdaily.com/for...l=1#post343307

  19. langel is offline
    This user has no status.
     
    Master TTD Member 1,060 2,225
    L
    langel is offline
    This user has no status.
     
    Master TTD Member 2,225 1,060
    #19
    Quote Originally Posted by lodro

    very interesting but here is my experience:
    I have a very flexy blade, Sanwey J7, it has some 61 seconds Eagle rubbers 1.5mm H40 no problemos for me to play with at all
    I also have a TPS BlockmanII stiff as a brick blade with double boosted H3 Neo 37 2.15 mm again no problemos for me to play.
    ???????????

    So what exactly is your statement?
    Give us some more of your feelings with these combos - how do they perform in active and passive play, etc.

    "No problem" is neither a definition nor an explanation.

    I have many blades of different stiffness, with rubbers of different hardness too, and I have no problems playing with them, but they really perform very differently and I know when and why to choose a particular combo. This statement is nor for this thread only, I've said in many threads what I choose, where and why.

    So please clarify what is your personal feelings and how and why you would oppose my statements.

    My statements are absolutely right and correct and even BB would not deny.

    Of course every statement, though true, may be expanded to higher level of abstraction. But usually I desist apart from unnecessary sophistications.


  20. lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 244 703
    L
    lodro is offline
    says TT-CLOWN, old git
     
    Senior TTD Member 703 244
    #20
    Quote Originally Posted by langel

    Very flexy blade with hard rubbers would be very difficult, or even impossible to control,

    One has to adapt to every set-up.
    If I can adapt to a setup that you describe as difficult or even impossible to control then most people should be able to do it.
    Feelings are an individual thing.
    My very first time playing ping pong all we had was a 1mm layer of cork on either side of the blade, i am sure that this would feel quite different to play with now

    Last edited by lodro; 4 Weeks Ago at 07:23 PM.

Page 1 of 4 1234 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Create a new Topic:
Title is required.