OOAK Table Tennis Forum

So when are you going to remove all those comments made by others?

You have a double standard.


What about me? I didn't get any respect so I don't feel the need to reciprocate. See these posts from the other thread.

[quote=silver]
Not an attack on anyone here, but I think a lot of people have been drawn in by some internet kiddie with a basic grasp of statics and dynamics spouting equations and drawing conclusions on the most base model possible.
[/quote]







[quote=hclnnkhg]
Another physics model by no engineer but a high school student
[/quote]

[quote=speedplay]
And no, you have been ignorant to what other members have said, you refuse to even consider that you might be wrong on this.
[/quote]




I see, so this respect thing applies only to me. Well I will leave you all alone if you leave me alone. Why would I want to contribute anything here after the crap I got. I did not start this thread. I wouldn't have posted anything if the comments weren't made about me. I was happy to let you all believe weight=power. This wouldn't have got out of hand if haggisv would have squashed the derogatory comments at the start but you didn't so squiros felt he could 'pile on'. I am not going to stand by while comments like squiros' are made especially when it is clear he has no idea what he is talking about. It is also clear he ignored the 30% of the comments that understood what I am saying.

It is sad that only ttgame made the effort to understand and actually do the math to verify what I said.
I respect the effort that ttgame has made. The other that made critical remarks deserve none.

_________________
I play TT for the health of it.
Samsonov Alpha FH Apollo BH Mark V max 178 gm Testing if tacky rubbers are better for serving.
My Blocker, 729 Bomb, FH Reflectoid 2mm, BH Pogo 0X 150.51 gm $40

No it applies to everyone, but most other people remarks were in response to yours. It seems that instead of accepting that you've made some arrogant and be-littling remarks, you choose to blame others for their remarks.

I personally found your comments quite useful and they made a good contributions, but if you can't make them without be-littling others, I'd rather not see them at all. We're a very friendly mob here pnachtwey, and it is extremely rare that we have incidents like this, so if you can't see that you've at least contributed to the unfriendly way these thread are going, I can't help you.

As speedplay said so well:

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Personally, i seem to hit my forehand faster with a heavier blade, but i hit my backhand faster with a lighter blade...i wonder if a straight trajectory stroke would be different then a a stroke which requires minor deviations from the wrist and thus changing the trajectory slightly through the stroke of the ball? I am talkin about hitting a low push with a powerloop or drive stroke, i am not talking about a flat hit or smash but a stroke that requires a sensible arch in the ball at the same time...usually on top or close to the table...once you are more then 3-4 feet away full strokes might have a different response! next time Pearson is in town i will pose the question to him?

Back on topic, I think pnachtwey stated in the last thread here that mass did have an impact on speed to some degree. All else being equal besides the density of the wood basically means one blade has more mass than the other due to the wood fibre structure. Now as players, most of us can feel the impacts of a faster and slower setup and to some degree we can see it on the ball velocity. However, what we can't say (unless we have a radar setup to measure speed) is what the actual speed of the ball is when struck with equal power with the different weighted setups. I doubt anyone can accurately say by eye a ball travelling at 110kph is faster than one travelling at 108kph. Obviously you can tell if one is at 50kph versus 120kph, but that is not the speed difference we are talking about. Human judgment is affected by all sorts of factors and is inherently inaccurate when it comes to fine measurement. So while our "feeling" and our "logic" and even science tells us there is an impact on speed with greater mass, no-one can say what the actual difference is without a real world model which measures that actual ball speed under controlled conditions. The theoretical models should approximate the results provided the right assumptions and formulas have been used.

No need for any put-downs in the discussion as you put 10 academics in a room from just about any faculty and you'll often get 10 different answers. Just ask 10 economists on what will happen to the world economy for the next 10 years

_________________
I'm always in the dark, but the Dark sheds lights upon everything!! Beauty is only pimple deep! Beauty is in the eye of the pipholder!
S/U 1: Blade: Bty Gergely . FH Black Andro Rasant 2.1 . BH Red Tibhar Grass Dtecs
S/U 2: Blade: Bty Gergely . FH Black Hexer+ 2.1 . BH Red GD Talon
S/U 3: Blade: Bty Gergely . No rubbers...thinking of adding Red Dtecs and Black Rasant
Aussie Table Tennis Shop / Aussie Table Tennis Facebook Page / Equipment Review Index / Read my Reb Report Blog: click here.

The equations and discussion of COR are correct basic physics results but they represent a highly idealized situation that does not represent real world experience of a TT bat and ball collision. As a result, people are arguing over how much greater understanding of blade+ball collision behavior is being gained but no one is armed with the tools to study, understand and then coherently present a more complex model that better represents real behavior.

There has been no discussion of the Effecitve COR (ECOR) which takes into account where on the blade the ball strikes, the energy that the collision couples into the blade vibrations, or the efficiency of the vibration constructively or destructively coupling back into the rebound of the ball (i.e. the ECOR is also varies with impact velocity and the blades effective mass at the point of impact). There are also the complexities of how swing differences distribute kinetic energy into the rotational and translational motion of the blade, axis of rotation (spine, shoulder, wrist, whatever), and how those effect ECOR since when the blade is rotating, the tip is moving faster and thus results in a different ECOR than would be measured if the blade was not rotating but traveling with the same center of mass velocity. The more complete physics model would also have to account for the bi-mechanical power that the player can provide to bring the blade to collision speed as a function of its mass (inertia) and its mass distribution resulting in a moment of inertia (rotational inertia, swing weight).

Still, there are some things that can be taken from bat+ball, and tennis racket collision studies that can help.

You can see from baseball batting versus bat swing weight studies that the heavier, higher swingweight bats do hit the ball farther (greater blade mass and effective mass = greater power), but the gain is fairly shallow and later begins to decline as one gets to weights beyond the power limits of the player. The increasingly lighter mass and/or swingweight bat results in increasingly somewhat less power (but this power loss rapidly accelerates once the velocity limit of player swing speed is reached), and better reaction time to the uncertainties in pitches so that hitting percentage rises. In table tennis, one would see this effect as having better reaction speed to uncertainties in direction and spin to the incoming ball. A light blade will pickhit faster because you can reach reasonable blade velocity and power with the short flick/pick swing but the same blade will not reach the power levels of a heavier higher swingweight blade during long swing away from the table counterlooping rallies. By placing a weight at the tip of a light blade, you will increase its swingweight and power at the tip without substancially increasing the overall weight. Tennis players do this to make their service power (ECOR at the tip) nearly equal to a more center struck ball.

In the end, your body and senses will tell you what blade and rubber combination is giving you more power and the trick is finding the combination that matches your swing-mechanics power envelope and game play style. Its hard to solve for this stuff analytically without resorting to dynamically modeling the collisions and swing mechanics interaction using a variety of tools.

So those previous 'belittling' remarks made by others don't count. I can see that it is one sided here.


I am not going to contribute here anymore. There is no point in it.

[quote=JRSDallas]
There has been no discussion of the Effecitve COR (ECOR) which takes into account where on the blade the ball strikes,
[/quote]
We never got that far. The goes for the other points you brought up. I realize that the simple equations work for a flat hit that should have been all that is necessary to make my point. BTW, you have always had good info.


The ratio of the weights between the base balll and base ball bat is not the same as a TT ball and and paddle. Base ball bats have different lengths they are rotating so it is rotational inertia that is important instead of simply mass. It is the fact that the paddle weighs so much more than the ball in TT that makes the extra mass do little more. I have seen documents on COR and base ball. I will look them up but I will not post the info here.

Why is a light BTY Ishlion fast or OFF and heavy defensive blades slow or DEF+? Don't bother to answer that here because I am not going to reply here.

_________________
I play TT for the health of it.
Samsonov Alpha FH Apollo BH Mark V max 178 gm Testing if tacky rubbers are better for serving.
My Blocker, 729 Bomb, FH Reflectoid 2mm, BH Pogo 0X 150.51 gm $40

I understand what hookshot and speedplay are saying about weight vs power (see my first post) but this topic has gone in other direction.

I dont't know pnachtwey and don't work with him.

I am reading this forum for a long time but only because of this topic felt a need to register and discuss. Because I felt there was misunderstanding and because I don't like to see when many people are discrediting some person' s arguments just because they don't understand it.
For me this is about bigger (than tt) truth - laws of physics. And it's applicable to all sports and stuff that surrounds us.


I don' t get it why you banned pnatchwey. Personally I found other people's comments about him more insulting than his comments. After all, he was the one that was being attacked. He was called "self proclaimed engineer", "using fancy terms", "no engineer", "likes to pretend he is smart", "some internet kiddie". For me it is insulting and he had every right to defend himself.
As I see it: squiros tried to prove that pnachtwey is wrong, but instead he said some stuff that doesn't make sense, and in a rude and unpolite way.
Nobody said a word to squiros and after pnachtwey responded (in defence) in the same manner, everybody was against him.



In fact first few posts are all about formulas and numbers and squiros initiated this topic with theoretical formulas (not real world experiences).

Back to the topic:

JRSDallas's comments about baseball bat show that, with all due respect, he doesn't understand the main issue here. Comparing baseball bats with tt bats is wrong and misleading. As pnachtwey said, weight difference is not that big and then we have some other "fancy formulas".

Now to subtopic:

I have 68 g Galaxy T-11 and it is faster than 86 g Tibhar IV-L.
Then again, 86 g Grubba is slower than 87 g Galaxy K-4.
80 g Yasaka Sweden Classic is slower than T-11 but faster than Grubba.
I don't have two of the same brand so can't say about that.
I like the feeling of heavier bats, but with lighter ones I can play all-out attack game closer to the table due to quicker backhand-forehand transposition and quicker wrist.

I hope I wasn't disrepectful and unpolite.

Not at all, You seem very nice.
My comment came when you used similar arguements. I gave real examples and that is what people here were wanting an explanation for. There never was an explanation for my example of identical bats with different weights having different speeds. I know it is because of the different density and the difference was big.
I have a scientific background and understand most of what was said but it should have become obvious what the anger was about. pnachtwey has a way with words that is aggravating to most people. I will not miss him.

The original topic was power vs weight and everyone agrees that more weight does provide a little more power. How much is up for debate and I'm afraid my opinion carries no weight . All sorts of factors from wood density, momentum were mentioned. In a sense, we are all off topic don't you think? But they are sort of relevant.

So the question I have is what are the factors you think produces more power and how would you rank them? For me, speed of impact is at the top of the list by a mile. Fortunately, this comes from the player so Butterfly can't charge an arm and a leg for it.

I was writing a response to explain how the baseball bat and baseball do in fact represents weight ratios that are found at points within the effective weight range of TT bat and TT ball collisions. Once I wrote it all and listed some points, I realized why people experience the weight correlation with blade speed that they do.

When I pressed submit, my posting was apparently lost due to my having timed out. I'm going to send this warm up first and then submit the explaination.

pnachtwey I'm sorry, but you simply don't seem to 'get it'

dajdosta: pnachtwey rude remarks were not just in this thread, but also in an earlier thread where this all started, and even in a PM to me . I have warned him twice already, but it seems he can only see faults in others, not himself. Warnings are usually done via PMs, but as our actions were questioned publicly, sometimes we respond within the discussion. It's not easy to run or moderate a forum, but keeping discussions friendly and respectful to other is one of our highest priorities and benefits everyone. I'm sure you would agree with that.

Sorry about the disruption guys, I hope we can continue this discussion, as it's a very interesting subject

_________________
OOAK Table Tennis Shop | Re-Impact Blades | Butterfly Table Tennis bats
Setup1: Re-Impact Smart, Viper OX, Victas VS 401 Setup2: Re-Impact Barath, Dtecs OX, TSP Triple Spin Chop 1.0mm Setup3: Re-Impact Dark Knight, Hellfire OX, 999 Turbo
Recent Articles: Butterfly Tenergy Alternatives | Tenergy Rubbers Compared | Re-Impact User Guide

Thanks JRSDallas, that would be great!

_________________
OOAK Table Tennis Shop | Re-Impact Blades | Butterfly Table Tennis bats
Setup1: Re-Impact Smart, Viper OX, Victas VS 401 Setup2: Re-Impact Barath, Dtecs OX, TSP Triple Spin Chop 1.0mm Setup3: Re-Impact Dark Knight, Hellfire OX, 999 Turbo
Recent Articles: Butterfly Tenergy Alternatives | Tenergy Rubbers Compared | Re-Impact User Guide

OK got to type the baseball bat and baseball validity fast. It timed out again last time I tried it.
Issue at hand is that TT bat to TT ball weight ratio is much higher than weight ratio of Baseball bat to baseball, so analog appears to be invalid.

A simple test shows that the effective weight of the TT bat at some points of impact is essentially nearly equal to the weight of the TT ball, i.e. a ratio much lower than the Baseball bat to baseball weight ratio. This then would show that the TT bat and TT ball playing condition contains the Baseball bat and baseball ratio so that the analog would be a valid weight ratio and thus invalidate the objections expressed.

A simple test shows this. Take a bare TT blade and using the heal of your hand and body weight clamp it down against a sturdy heavy table, preferably just above a leg, and with the leg resting on a hard floor (no carpet). Make sure the blade face is parallel to the table so it can vibrate without hitting the surface. Also make sure the blade is not rocking on a high spot on the blade handle.

Now drop a ball from a few feet up onto the blade center line somewhat towards the handle from the center of the blade face. Bounce it a few times and notice the height of the rebound and the high pitch of the rebound. The highest bounce spot is the point of maximum coefficient of restitution (COR) and this is the best spot to use when blocking (i.e. a stationary blade blocking an incoming ball).

Now drop the ball on the center line but as close to the tip as possible without hitting the edge. Now the rebound will be greatly diminished and with some blades and perfect drops, you might see the ball hardly rebound at all. At this point the effective mass of the blade is essentially equal to the ball since the ball's energy nearly entirely transmits into the blade. This is just what happens when first billiard ball squarely hits a stationary billiard ball. The first ball stops and the second ball takes off. This tip area is the best part of the blade to flat hit smash a pop up ball with since it is the most efficient spot to couple blade energy into the ball. Those of you who are flat hit smashers will fondly recall the rare but welt creating power of a perfect smash....if you can't remember now, when it happens again, you'll probably realize that you hit the ball near the tip of the blade.

Time is up. Need to post.

Table tennis loop strokes certainly do have rotation. That's why a 90g bat can feel like it weighs 5kg mid swing. That's why an 80g head heavy bat feels heavier than a 90g handle heavy bat.

I guess this is one of the variables he failed to include.

JRSDallas, if a post takes a while to write, its easier to do it in wordpad or something and then copy it into the forum window just before posting. I have lost a few posts before. Also, depending on your browser, some will just allow you to hit the back button and your post is still there.

_________________
I'm always in the dark, but the Dark sheds lights upon everything!! Beauty is only pimple deep! Beauty is in the eye of the pipholder!
S/U 1: Blade: Bty Gergely . FH Black Andro Rasant 2.1 . BH Red Tibhar Grass Dtecs
S/U 2: Blade: Bty Gergely . FH Black Hexer+ 2.1 . BH Red GD Talon
S/U 3: Blade: Bty Gergely . No rubbers...thinking of adding Red Dtecs and Black Rasant
Aussie Table Tennis Shop / Aussie Table Tennis Facebook Page / Equipment Review Index / Read my Reb Report Blog: click here.