Alex Table Tennis - MyTableTennis.NET Homepage
  New Posts New Posts RSS Feed - paddle mass and speed
  FAQ FAQ  Forum Search   Events   Register Register  Login Login
tabletennis11.com

paddle mass and speed

 Post Reply Post Reply Page  123 4>
Author
Speedplay View Drop Down
Premier Member
Premier Member
Avatar

Joined: 07/11/2006
Location: Sweden
Status: Offline
Points: 3405
Post Options Post Options   Thanks (0) Thanks(0)   Quote Speedplay Quote  Post ReplyReply Direct Link To This Post Topic: paddle mass and speed
    Posted: 01/20/2011 at 8:44am
Have to disagree with you here nicefrog. I've got 3 Dawei Wavestone blades, 2 of them weighing in at ~95gm while the third is about 10gm lighter and the difference in speed between them is actually quite big. I'm feeling fairly confident that the difference is more then 1% between them. Off course it can be argued that even the 85gm blade is fast enough, which it is, but this wasn't the point.
The holy grail
Back to Top
Sponsored Links


Back to Top
nicefrog View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 06/12/2008
Status: Offline
Points: 2398
Post Options Post Options   Thanks (0) Thanks(0)   Quote nicefrog Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 10:25pm
Well if the arm speed and all other things are equal there is some increase in speed with weight but I also am I'm sure it's so small on the same blade with the same composition it's irrelevant and I'm also sure that you can more than compensate with extra speed from a lighter blade :) (depending a bit on the build and speed of the player). In the end we are arguing about 1% in speed either way. Brand of balls or humidity/temp in the air or what you had for dinner probably count for more :)

Back to Top
Speedplay View Drop Down
Premier Member
Premier Member
Avatar

Joined: 07/11/2006
Location: Sweden
Status: Offline
Points: 3405
Post Options Post Options   Thanks (0) Thanks(0)   Quote Speedplay Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 5:09pm
ROFL!

Can't belive this still goes on.

Can't resist to post here.

Pnactwey, I don't think any one have ever claimed that weight is the only factor for speed. What I have read, and agree with, is that if you have 2 paddles of the same model, the heavier one is faster. So, will you please stop bringing up heavy slow blades and compare them to fast light blades? This isn't relevant to the topic, as we all know that the material used is the most important thing, but when this is the same, the material with the higher density (=higher weight) is faster.

So, why don't every one go out and look for a 300gm paddle? The obvious answer should be, why don't every one play with a carbon blade? Why don't everyone go for the Off++ blades? Perhaps because we don't want that much speed? Some people prefer slower blades, while other prefer faster blades, but I do think we all have a limit to how fast we want our blades to be.

Kind of funny, cause I remember when you (still talking about pnachtwey) claimed that there where no relation between speed and weight, but now I read that you admit that there is a relation and that the heavier blade is slightly faster then the lighter blade... Nice to see you are starting to understand, now if we could only get you to understand that this slight increase in speed can be felt/noticed by the user of the blade, we could actually agree.
The holy grail
Back to Top
tompy View Drop Down
Super Member
Super Member


Joined: 06/12/2010
Location: Netherlands
Status: Offline
Points: 222
Post Options Post Options   Thanks (0) Thanks(0)   Quote tompy Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 8:19am
Speed is relative the speed of the incoming ball should be taken into account also or it's for a popped up servereturn only ?

Suppose countering a somewhat higher fast loop with a smash. It,s not just adding energy then but also using the energy (being able to) the ball allready has. Elasticity and deformation of the ball comes in then also. For a fast smash you can use that elasticity as well as elasticity of the rubber and wood. But also with a too short impact the deformation stops to work elastic. Hitting harder doesn,t ad anything then because with the short dwell the forces become too strong for a tiny piece of celluloid.

The energy the opponent experiences coming back is a sum of his own energy plus something added and has a spin plus speed factor. With a blade that doesn,t accept the ball in for a longer moment the elasticity of the other parts (rubber, ball) can,t be made effective. The ballcontact can be too short, too much deformation the celluloid behaves less elastic aso. These somewhat old school fysics formula,s (including these laws of preservation of momentum and impuls seperate) typical neglect elastic behaviour and for tabletennis you can,t do that an have a realistic idea.

Also to be taken into account is that for energy for a tabletennisball a smash is never the most powerfull stroke and less the further from the table. Simply because the energyloss during the trajektory to the opponent is much bigger for speedfactor then for spin. Spin can carry further due to the construktion of the ball.

Different setups the spin / speed ratio is different for the most powerfull stroke. A def blade the optimal ratio (aimed to be experienced by the opponent) will be more towards spin and with enough speed and heigth to reach the net. There is an optimal ratio and an optimal curve (comes from it) also. There the cool starts to loose a lot because with tangential strokes the rubber needs more dwell to perform optimal as the topsheet rubber behaves more elastic it takes some time and the blade must allow that. The blade is a tool and the rubber also and the player has to make them work together to get that magical shot (the bang impact ?). 
It,s also what someone is used to play with. Changing from a 70 gr to a 90 gr blade is huge. To compare you would need to play with it for a few months and adapt technicque and timing to get the best out if it.
I prefer and play with blades near 90 gr. Longer time so my technicque and timing developed to get the best out of these blades. I also played a few years with a tsp balsa 6,5 mm core with glasfibre. Pretty fast blade. In the medium range of impact similar then clipper but for powerlooping further away not even close. For lower impact and/or  more flat strokes it was faster.

The "bandwith" was much more limited and the spin/speedratio for the optimal stroke more towards speed and less spin. It also made my strokes too short and my technicque got worse because a fullstroke was not rewarded. I could put energy in with hgiher contactspeed but not able to bring it out during the then shorter period of ballcontact.

Heavier powerfull rubber also has longer dwell and I couldn,t use these on that blade. It performed best with softer light quick rubber. But the setup as a whole then performed at lower level.

I felt the strength of the tsp was more in the quickness playing short range especially for bh. Being able to use a short stroke and placementdeception the supprise factor was bigger then with a clipper. But two stepsback being ableto use a somewhat longer stroke the clipper becomes faster for me. Offcourse if the weight is only deadweight not taking part of the action or with a too low frecquency the weight is only added weight. Like most of the rubber is dead weight not elastic part of the energytransfer except for the small area where the ball is hit. For a blade that funktions mostly by surface spring and little flex this works more or less the same. Materials near the neckzone are highly effective/funktional for every stroke.

And there lies a significant weakness for tabletennisblades also. The optimal build a blade would have to be made thinner towards the tip, similar to a fishing road. Then the materials could be used more optimal and certainly also the carbon. Then I can imagine making a lighter blade more powerfull. But unfortunately this is not allowed for ittf rules.
But with the thick balsa blades because the energy/elasticity comes from surface spring mostly a relatively high part of the materials is not funktional and the neckzone is not funktional...too thick for powerlooping and a powerloop is the most powerfull stroke for the opponent to deal with.

On short range the lightweight blade could have advantage though. Then the lack of time for a more full swing (and using hiprotations, knees aso for accelleration) plays a bigger role and then the arguments for a lighter blade will weigh in more. But for playing more close to table I would still prefer a normal weight blade and then search for somewhat lighter rubber.





Edited by tompy - 01/19/2011 at 12:05pm
Back to Top
nicefrog View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 06/12/2008
Status: Offline
Points: 2398
Post Options Post Options   Thanks (0) Thanks(0)   Quote nicefrog Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 2:02am
Well for me, switching rubbers while everything else remains the same you can change the height of the ball over the net by several centimetres, maybe even 10 in extreme cases. I wouldn't be brave enough to say to lowest throwing rubber would be the least spiny because in my experience that's not been the case. I still don't go for the heavy blade being faster theory, a Joola Kool at 75 grams is still going to be a crap load faster than a 100 gram TBS even swung at the same speed, and you will be able to swing the kool faster :) so you do need to take into account what the blade is made from

Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 1:43am
Originally posted by pnachtwey pnachtwey wrote:

Originally posted by yogi_bear yogi_bear wrote:

why separate the material and mass when both are components of a racket?
Yes, but just because the mass of the paddle is greater doesn't mean it is faster.  It is the material that makes a huge difference.

You have made it clear you don't believe the mass of the paddle increases speed.  If you did then you would have gone along with the 300gm paddle idea.

no you are the only one with the idea of using 300 gm paddles since we people in the forums except you are realistic and we believe too heavy of a racket will cost us our swings! you are unrealistic about its mass is part of the reason it increases speed. whether minimal or optimal it increases speed. 
[quote]
as what i have been saying in the past posts prove it in real experiments not just theories.. you always fail to put into account the practical applications!
What about the slow and heavy defensive paddles? Explain that!  You have to know that increasing the mass alone does not result in more speed.  If you thought otherwise you would have a 300 gm paddle.
you seem to have no idea about defensive paddles do you? our number player in our country is a defensive player and a chopper. his blade is not slow. a fried of mine who uses joo see yuk blade (it is considered a defensive blade for a chopper). it is not a slow blade and it is heavier than normal bladeS!

stop making up stories about 300gm blades! people will not use it nor us here! if you consider yourself a true logical person why disregard other factors and just use the ones you think are for just backing up your claims? why not use all of them? that's what makes your claims unrealistic
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/19/2011 at 1:32am
as


Edited by pnachtwey - 03/20/2012 at 4:32am
Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 11:59pm
why separate the material and mass when both are components of a racket? as what i have been saying in the past posts prove it in real experiments not just theories.. you always fail to put into account the practical applications! would you like me to remind you about your posts on "throw angle is bull"? 
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 11:40pm



Edited by pnachtwey - 03/20/2012 at 4:32am
Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 9:42pm
my 105 gm DHS 08 is faster than my 92 gram ebenholz both with neo skyline 3 on them, 
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 8:10pm
as

Edited by pnachtwey - 03/20/2012 at 4:33am
Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 7:57pm
"Good question, but there are still those that think that heavier paddles result in more speed so why not buy a 300gm paddle if they really think it is true?  What I am trying to debunk is all the posts that say heavier paddles have more power.  By that I think they mean a higher speed after impact for the ball.
The mass alone doesn't make that much difference to the speed.  

It is obvious that you haven't read or understand the posts and the point I have been trying to make and just want to criticise."

says who? who are the ones who think that using a 300gm blade will make their game faster? you are making up stories again to support your claims! it is also obvious that you don't have the logic to support and clarify your statements.. Nobody is stupid enough to think they would get 300gm paddles, you are the only one thinking about that not us! 
 
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 1:05pm
as


Edited by pnachtwey - 03/20/2012 at 4:32am
Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 8:12am
Originally posted by pnachtwey pnachtwey wrote:

Originally posted by Anton Chigurh Anton Chigurh wrote:


The empirical consensus is already in, and it is that heavier blades are usually faster.
What about the heavier and slower defensive paddles?
Why not use 200 gm blades and 300 gm paddles for more speed  if you really think mass is the deciding factor.   I don't see anyone buying 200 gm blades yet.


why would someone be that stupid to buy a 200 gm blade and play with it? this is far from reality since most blades with rubbers on both sides weigh from 160-175 grams. 
heavier and slower defensive blades have different wood constructions? why not compare blades on the same speed rating or compare 2 blades with 2 different weights like a clipper wood classic which is 84 grams and 92 grams for example. with the same rubbers on both sides and test it on a radar speed? 
tsk tsk tsk SID
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
tompy View Drop Down
Super Member
Super Member


Joined: 06/12/2010
Location: Netherlands
Status: Offline
Points: 222
Post Options Post Options   Thanks (0) Thanks(0)   Quote tompy Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 2:38am
Originally posted by pnachtwey pnachtwey wrote:

Tompy, the conservation of momentum is a fundamental law of nature or physics.

That,s also what I was told. But I happen not to agree with this idea. To me the sum of momentum and impuls has to be constant but not on themself. How they relate seperately and together to energy then (also assumed to be preserved) I don,t know how of if that could be put in formula,s but still I disagree with this idea of preservation of momentum and impuls as seperate in the sense of qualitywise for my understanding.

If I keep a bat with grippy rubber still not doing anything and touch a spinny ball with hardly any impuls the ball jumps off with a significantly higher speed and a decrease in spin. To me that,s a clear example where spin (momentum) converts into impuls. If fysics tells me this is impossible because both are supposed to be preserved then I don,t take the fysics too serious on that.

Examples in tabletennis where impuls converts in momentum are also plenty to think of. Like a block on a smash only keeping the blade and catch the ball in the rubber. a ball with no spin can jump of with spin. decrease in impuls (for the blade and the ball together before and after offcourse) and increase in momentum.

On a billarttable it maybe shows even better how a spinning ball can accelerate from the side of the billart. If there impuls and momentum are preserved seperately then I have to imagine that the billart moves and rotates afterwarts. That,s too much for my imagination. I see the total of impuls and momentum preserved in such cases maybe but not both seperate.










 




 
[/QUOTE]
Back to Top
infinite_loop View Drop Down
Super Member
Super Member


Joined: 12/21/2007
Location: United States
Status: Offline
Points: 154
Post Options Post Options   Thanks (0) Thanks(0)   Quote infinite_loop Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 2:25am

The root cause of the "controversy" is pretty simple: mismatch in expectations of which variables are kept fixed in the experiment.  

Generally, when players talk about of effect of varying mass, they implicitly assume that the thing that is kept fixed is the type/construction of the blade. 

Players talk about difference in speed between a 88g TBS vs a 95g TBS vs a 102g TBS. The heavier blades tend to be made of denser wood and have higher COR. 

Or, blades of the same family with similar construction. e.g. a 80g OC vs a 95g Clipper. Heavier blades tend to be thicker and/or use denser wood and have higher COR.

If you are more of a physicist, keeping COR fixed is a natural thing to do in this experiment. If you are more of a player than a physicist -- most forum members are -- keeping something like COR fixed is unnatural. If the fixed part of the experiment is conveyed properly in a way everyone really understands what it is, there is unlikely to be much disagreement. 

e.g. a 78g Yinhe T2 vs a 95g Clipper. Players of course know that a lighter blade can be as fast or faster in that case.

In fact, if we eliminate the mismatch in expectations, I am pretty sure we will arrive at this conclusion: what players informally describe as blade speed is COR.

Anyway, this thread reminds me of a joke.

What is the difference between an engineer and a theoritical physicist? 
An engineer believes his equations approximate the real world. 
A theoretical physicist believes the real world approximates his equations.



Edited by infinite_loop - 01/18/2011 at 2:34am
Back to Top
Anton Chigurh View Drop Down
Premier Member
Premier Member
Avatar

Joined: 09/15/2009
Status: Offline
Points: 3962
Post Options Post Options   Thanks (0) Thanks(0)   Quote Anton Chigurh Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 2:03am
Originally posted by pnachtwey pnachtwey wrote:

Originally posted by Anton Chigurh Anton Chigurh wrote:


The empirical consensus is already in, and it is that heavier blades are usually faster.
What about the heavier and slower defensive paddles?
Why not use 200 gm blades and 300 gm paddles for more speed  if you really think mass is the deciding factor.   I don't see anyone buying 200 gm blades yet.



I've never used a DEF blade so I cannot speak from firsthand experience. However, I've been told by more than one defensive player the DEF blades are not "slow", by any means.

Regarding your comment on the enormous weight of 200g and 300g, I think you're being disingenuous... and I think you know it. Wink

Obviously, whatever benefit is gained from a heavier blade, there will eventually be a point of diminishing returns with regards to maneuverability, etc.

But don't get too defensive. I did leave room in my comment for the possibility that your evaluation is correct. But if I had to make a guess today then I'd say I don't think it is, simply because of my own experience and the input of many, many, many others whose experience exceeds my own.


Neo H3 40D| Offensive S | Tenergy 80
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/18/2011 at 1:50am
as


Edited by pnachtwey - 03/20/2012 at 4:33am
Back to Top
Anton Chigurh View Drop Down
Premier Member
Premier Member
Avatar

Joined: 09/15/2009
Status: Offline
Points: 3962
Post Options Post Options   Thanks (0) Thanks(0)   Quote Anton Chigurh Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 9:52pm
Originally posted by hulkpens hulkpens wrote:

The professions/education of this forum's members is showing thru this thread.

When you guys are done, let me know what the consensus is.


The empirical consensus is already in, and it is that heavier blades are usually faster. For example, I've experienced firsthand how two blades of the exact same model, only differing in weight (by about 7 grams), are noticeably different in speed. However, it is pnachtwey's claim via his equations that are causing the controversy.

It is quite possible that pnachtwey's claims are correct, as not all things in the "real world" match up with our intuitions. But I'm skeptical, especially because assumptions must often be made when crunching the numbers and those assumptions can sometimes miss crucial data. This conversation has gone far beyond my abilities to comprehend so I'm sticking with my intuitions. Zeio's claim that the COR actually does take into account the paddle mass, just at a lower level of abstraction, made sense to me... but that was many posts ago and I've already forgot why it did. LOL

It doesn't really matter to me in practical terms because I'm going to use whatever is comfortable. But theoretically I wouldn't mind knowing the "right" answer to this query just because I'm compulsive like that. Wink


Neo H3 40D| Offensive S | Tenergy 80
Back to Top
hulkpens View Drop Down
Beginner
Beginner


Joined: 09/22/2010
Status: Offline
Points: 98
Post Options Post Options   Thanks (0) Thanks(0)   Quote hulkpens Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 9:39pm
The professions/education of this forum's members is showing thru this thread.

When you guys are done, let me know what the consensus is.
Back to Top
figgie View Drop Down
Gold Member
Gold Member


Joined: 01/28/2005
Location: United States
Status: Offline
Points: 1026
Post Options Post Options   Thanks (0) Thanks(0)   Quote figgie Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 9:26pm
mass and speed or mass and velocity? What about acceleration? Kinetic Energy? Moment of Inertia? elastic or inellastic collision? Entropy of the system? How much wood would a wood chuck chuck if a wood chuck could chuck wood?

Edited by figgie - 01/17/2011 at 9:27pm
Speed glue, booster, tuner free since 2006!!!
Back to Top
Best99 View Drop Down
Super Member
Super Member
Avatar

Joined: 01/08/2010
Status: Offline
Points: 399
Post Options Post Options   Thanks (0) Thanks(0)   Quote Best99 Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 9:22pm
Wait wait wait...

We should also take into account other blade's characteristics, such as stiffness and hardness.

Appart from that, let's think it this way.

Let's consider 2 blades, A and B, which are made from the same material, have the same shape, the same size but that have different weights (which is physically speaking impossible).

If A is heavier than B, its density will be higher, so A is denser than B.

A denser material will have less COR, because the molecules are closer to each other.

It doesn't matter the material, its characteristics, its density, etc, if two paddles are the same shape and size but one is heavier than the other, the heavier WILL be faster.
Blade: Timo Boll ALC 92 g.
Forehand: Tenergy 05 2.1 mm. (black)
Backhand: Tenergy 05 2.1 mm. (red).
Perfect loops
Back to Top
yogi_bear View Drop Down
Forum Moderator
Forum Moderator
Avatar

Joined: 11/25/2004
Location: Philippines
Status: Offline
Points: 7219
Post Options Post Options   Thanks (0) Thanks(0)   Quote yogi_bear Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 8:41pm
SIDomized thread
Independent online TT Product reviewer of XIOM, STIGA, JOOLA, SANWEI, GEWO, AIR, ITC, APEX, YASAKA and ABROS

ITTF Level 1 Coaching Course Conductor, ITTF Level 1 Coach
Back to Top
sweetstrike View Drop Down
Silver Member
Silver Member
Avatar

Joined: 11/30/2010
Location: California
Status: Offline
Points: 689
Post Options Post Options   Thanks (0) Thanks(0)   Quote sweetstrike Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 8:28pm
Quote If you change that to bigger head I will agree but the resulting speed still changes little.  If the dimensions of the paddle don't change and the heavier blade simply has more moisture then what is gained?   In most woods the coefficient of restitution goes down as the moisture content goes above 8%. Adding mass alone is not the answer.


If blade properties like thickness, stiffness and moisture content are kept the same, the only way to test a heavier blade is to use a larger sized blade. And the larger blade face will yield higher ball speeds across the face than a smaller blade face.

Quote Now that I look at it closer, I have problems with FIG6.  The reduced mass between the arm and the paddle is supposed to be mr=(ma*mp)/(ma+mp)  where ma is the arm mass and mp is the paddle mass. The resulting reduced mass should never be higher than the lightest mass.


Mr has to be greater for the blade+arm system than for the blade alone. Say your arm weighs 9 lbs and the blade is 1 lb. When you make contact with the ball, the reduced mass (essentially the weight of the hit) will not be less than 1 lb.

Quote In the speed after impact forumula use mass a as the ball and mass b as the reduce mass.  Sure the speed goes up with a higher reduced mass but it goes up very little as shown in FIG13.


I agree with you the effect does not appear to be substantial and that rubber/sponge choice has a much greater effect on the overall speed than varying the mass of the blade.


Edited by sweetstrike - 04/04/2013 at 8:52pm
Viscaria FL
FH: Tenergy 05 2.1
BH: Sword Scylla OX
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 2:30pm
as

Edited by pnachtwey - 03/20/2012 at 4:31am
Back to Top
tompy View Drop Down
Super Member
Super Member


Joined: 06/12/2010
Location: Netherlands
Status: Offline
Points: 222
Post Options Post Options   Thanks (0) Thanks(0)   Quote tompy Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 7:22am
All these figures and formula,s go from the idea of a speed on impact not acceleration during impact. (That,s timing and technicque also). Speed on impact means before it. The technical ability decides whether someone can release energy in the arm during the short moment of impact. The blade is a tool to make that possible and it needs weight for that (much more then the rubber) otherwise it,s resistance to energytranfer is too high due to a balsa core for instance.

The light head will also loose speed from if the player would not put momentum on the blade (like clamping it) even if you hit it in the sweetspot. Clamping a racket with the hand it becomes difficult to tranfer the energy from arm out to the ball during impact.
I believe the ideas of preservation of impact and momentum are highly primitive. In my experience with tabletennis impuls can transform to momentum. If you would look at both then there could be some preservation but apart from each other they are not preserved the impuls before collision can be lower if the momentum (or impuls of momentum how do you call it ?) had increased.

I experience this for instance with how a ball with spin accellerates from a rubber and jumps of. To me that,s a plain case of increased impuls (and decrease of momentum). It,s a decrease ofmomentum anyway because the momentum of the blade doesn,t change and the ball does. The sum is lower then. This comes out as an increase of impuls.

I think that,s the weak thing with all these formula,s. They are far too simple even if they may seem complex.




Edited by tompy - 01/17/2011 at 7:29am
Back to Top
sweetstrike View Drop Down
Silver Member
Silver Member
Avatar

Joined: 11/30/2010
Location: California
Status: Offline
Points: 689
Post Options Post Options   Thanks (0) Thanks(0)   Quote sweetstrike Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 5:17am

There's a really scientific discussion going on here and it's very educational. I think this figure posted by Zeio is the most important concerning the argument that a lighter blade is better.

This plot of the reduced mass across the face shows that the Mr decreases as you make contact away from the sweetspot. I wish they had made multiple plots for blades of different mass as I'm pretty sure the Mr plots will be slightly higher for a heavier blade at the sweetspot, but the curve will be flatter meaning there will be a lower reduction of Mr for off center shots.
 
This means that a heavier blade is more forgiving with a larger sweetspot. This is probably why many players prefer a heavier blade. Although it requires more force to accelerate, the end result is a more consistent shot.
Back to Top
tompy View Drop Down
Super Member
Super Member


Joined: 06/12/2010
Location: Netherlands
Status: Offline
Points: 222
Post Options Post Options   Thanks (0) Thanks(0)   Quote tompy Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 3:18am
I haven,t read this all but nowhere accelleration is mentioned as a way to lengthen the trajektory on ballcontact. Also referred to as "hitting through the ball".
Longer ballcontacttime offcourse means longer trajektory (In cm,s (if someone would want to do that but - at least qualitywise for understanding - time can also be considered trajektory).
If a paddle is accellerated to max speed before ballconstact allready and then only - sorta - follow through, maybe the arguments make sense. But that,s not how you ever manage to get the best loops.

Then it,s impact and almost immmediately the ball is gone with a short trajektory, low energy lots of vibrations. With a whipping accelleration starting shortly before ballcontact and continuing during ballcontact the ball can,t escape from the blade as easy. Contact is longer and with that trajektory and with that ...energytransfer. Hitting through is actually not the best choice of words..."accellerating through" would be better. And from max speed there is nothing to accellerate from anymore.

A case where this is more obvious in daily live would be a shoppingcar that rolls towards someone.

Hit it with maximum speed mostly results in sour hands. Take it in relaxed, accellerate gradually (all tuned and timed to the incoming objekt, taking it in feeling it,s energy) the trajektory can be lengthened and therefor -much - better energytransfer with no vibrations and a more smooth action.





Edited by tompy - 01/17/2011 at 3:28am
Back to Top
pnachtwey View Drop Down
Platinum Member
Platinum Member
Avatar

Joined: 03/09/2010
Location: Vancouver, WA
Status: Offline
Points: 2035
Post Options Post Options   Thanks (0) Thanks(0)   Quote pnachtwey Quote  Post ReplyReply Direct Link To This Post Posted: 01/17/2011 at 2:39am
as


Edited by pnachtwey - 03/20/2012 at 4:30am
Back to Top
zeio View Drop Down
Premier Member
Premier Member


Joined: 03/25/2010
Status: Offline
Points: 10833
Post Options Post Options   Thanks (0) Thanks(0)   Quote zeio Quote  Post ReplyReply Direct Link To This Post Posted: 01/13/2011 at 12:03am
Originally posted by pnachtwey pnachtwey wrote:

What about your FIG13 and your article?  You seem to be searching for fault and can't find it.

What an appalling statement.  You do not seem to ever be aware that the data presented in Fig.13 are collected using reduced mass derived from their respective moments of inertia at different predetermined locations(including center of mass and off-center) across the length of the paddle face, yet you take that part out of context at face value and manipulate your interpretation to the advantage of your twisted conclusion.  The moment of inertia, upon which all subsequent findings in that study are built, has long ago entered the fray ever since I posted the abridged study and first appeared in Table 1.

Originally posted by pnachtwey pnachtwey wrote:

You were the one that brought up rotation.   Read above   6DOF is the logical extension.  I can have have done the math for 6DOF motion platforms that is used in flight simulators.  It wouldn't bother me.
Rotation is beyond the scope of what I wanted to cover but most of us do use a lot of wrist action with our BH strokes.

I seriously doubt your reading comprehension.

In Figure 4, the caption for the impact model reads "Single degree of freedom model of impact between a racket and ball by introducing a reduced mass of a racket-arm system."

And that single DOF is acheived by limiting the motion of the paddle to pitching only(tilting forward and backward), hence the impact and center of mass locations chosen "along the longitudinal centerline on racket face".  Again, Fig.13 bases on that.

Given the findings in that study support the hypothesis that paddle mass and COR are correlated, it is logical for one to approximate the off-center mass to a lighter paddle and center-of-mass to a heavier paddle and estimate the effects.

Originally posted by pnachtwey pnachtwey wrote:

You seem to be troubled by the fact that you can't find a flaw and your document, FIG13, backs up what I have said.  Think about this.  Why is a light Ishlion blade OFF and heaver defender paddles DEF?  The difference is the material the paddle is made of.

Since JRSDallas has commented in an elegant way about this on OOAK, I will save my own trouble and quote below:

Originally posted by JRSDallas JRSDallas wrote:

Originally posted by 82828282 82828282 wrote:

Perhaps the increased weight is just a side effect of what really makes the blade faster. Which may be the denser material that returns more energy to the ball.

That's all pnach had to say, but instead he uses this idea to go on an ego crusade.


pnach did not comprehend that there was a connection between the weight and power. He was arguing that there was only minimal connection and that those claiming they felt a larger influence than was explianed by his math were obviously in error. The error however was that he did not understand the limitations of his math as a representation of the real world. He assumed his math was the truth, when in fact the real world is the truth and he did not understand that his math assumption was leading him to erroneous conclusions about the real world.

In the real world, it is reduced energy losses during collision that results in faster rebound velocity, and these reduced energy losses are achieve by having higher stiffness in the blade. The higher stiffness is achieved by using stiffer materials which when choosing only from the limited materials allowed for TT blades, almost always results in higher mass. Thus making the blade stiffer makes it faster (i.e. higher COR) , but this increased COR requires that the blades mass be higher!..

Now some blades have been specifically constructed to have higher COR at lower mass (Ishlion) than most other blades, and pnach's used the Ishlion's speed to weight to argue that his math was right.....but.....his actual argument was that people who said there was a correlaton with weight were wrong.
Unfortunately he did not understand what he did not understand and in both cases he was wrong.


If you compare two different weight Ishlions, the heavier one will more often than not be stiffer and therefore faster, and that this correlation is true for all blades simply because the increase in stiffness is intimately coupled to the engineering properties of the materials used in blades. pnach did not know that COR was in the end correllated with blade weight for valid physical reasons. COR was for him an abstract constant not connected with blade weight.


Originally posted by pnachtwey pnachtwey wrote:

You should look up internal friction

Look now who is bringing up obscure topic to the thread without any substantial reference.
Viscaria FL - 91g
+ Neo H3 2.15 Blk - 44.5g(55.3g uncut bare)
+ Hexer HD 2.1 Red - 49.3g(68.5g 〃 〃)
= 184.8g
Back to Top
 Post Reply Post Reply Page  123 4>
  Share Topic   

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.01
Copyright ©2001-2018 Web Wiz Ltd.

This page was generated in 4.938 seconds.

Become a Fan on Facebook Follow us on Twitter Web Wiz News
Forum Home | Go to the Forums | Forum Help | Disclaimer

MyTableTennis.NET is the trading name of Alex Table Tennis Ltd.

Copyright ©2003-2024 Alex Table Tennis Ltd. All rights reserved.