OOAK Table Tennis Forum

there was another topic here where there was an argument about power vs weight.

more weight is more power, obviously. the self proclaimed engineer fails on multiple levels. human beings are not infinite. which means that on light objects, we impart the same velocity, and we can go no faster. this limits the amount of force; the amount of acceleration. what this means is that a heavier bat will hit with the same acceleration as a lighter bat, for all relatively light bats. this means, that if A is constant, the force of the heavier bat will be greater.
force of heavy bat = heavy mass * A
force of light bat = light mass * A
this is obvious to any engineer who didn't fail out of undergrad. a mechanic is not an engineer, btw. at any rate, we're talking about the force generated at impact. which is this:
Force of bat after hit = Force of bat before hit - force given to ball
it is important to note that the heavier bat does not have That much more force, since air resistance is a function - meaning it will increase as things get faster. maybe you want to use 0.5 * m * v ^2. it doesn't matter, since mass will be linearly proportional regardless. v will again be constant at Vmax of a human.

also, this means that for heavier objects, say a 100 lb weight, acceleration will NOT be constant for a human. meaning a bat that weighs 100 lbs will impart a much lower force since most of us will not be able to get any meaningful acceleration, and consequently no force.

coefficient of restitution is irrelevant. it is the same whether you hit it with a heavy or a light bat. the coefficient is a CONSTANT, not a function, meaning it is always the same.

power is irrelevant. power = work/time. here, we assume everyone has infinite stamina, and can go all out on the ball every shot. this formula is UNRELATED to predicting speed. although the classical definition of power is 'how hard you hit it', in physics, all it means is effort/time. the formula "power = force * velocity" is meaningless, since it's not related to how fast the ball will go. however, this IS related to my actual question - do heavier bats make you tired That much faster? so if i usually play 2..3 hours with a 70 gram bat, and switch to a 90 gram bat, will i only play for 1.5..2.3 hours?

Hi Squiros,

I'm surprised you have chosen to bring up this topic again.

Whilst it is correct that a heavy bat swung at the same speed as a lighter one will produce a faster ball the effect is not very great.

I modeled the ball bat impact in excel and found : ( big simplification COR 1, totally elastic collision !)
ball 2.7g
bat 180 g
ball initial speed -7 m/s
bat initial speed 6 m/s
Bat speed after impact v1= 5.616 m/s
Ball speed after impact v2= 18.616 m/s
ball 2.7g
bat 200 g
ball initial speed -7 m/s
bat initial speed 6 m/s
Bat speed after impact v1= 5.654 m/s
Ball speed after impact v2= 18.654 m/s

10 % increase in bat mass only 0.2% increase in ball speed.Bit like if you hit a tt ball with half a brick or a full brick it doesn't come off much faster.

What this does mean is that if your bat is heavy enough that it is limiting how fast you get your bat to at impact then you very likely will not be hitting the ball as fast as if you had a slightly lighter bat. So for a small fella with weaker arm a lighter bat would be the go if your aim is the get as much ball speed as possible.

http://en.wikipedia.org/wiki/Coefficient_of_restitution
Now coefficient of restitution (is a measure of how elastic or inelastic a collision and is dependent on both surface material properties and the geometry of both surfaces)
is another matter and is very much a factor in how fast a ball comes off a bat or any object.
Going back to the brick analogy, image that same half a brick has a sponge glued on the front, this affects the coefficient of restitution vastly and slightly increase the weight and yet the ball will come off a lot slower.
Saying the "coefficient of restitution is irrelevant" is just wrong.
If this were true using different rubbers would make no difference to the ball speed which all players know is not correct.

There is a measure for power during a table tennis shot. Work is done by the player and during contact with the ball energy is transfered to the ball, using a force, over a distance and in a portion of time. When most people think of a table tennis shot as being powerful it is a measure of how much energy has been transfered to the ball and is evident in the energy the ball has, predominantly as kinetic energy both in terms of its velocity and it's rate of spin (rotational kinetic energy).

In saying all this we all have our own personal preferences and weight of bat and the feel/feedback to ones muscles etc is an important consideration.

"do heavier bats make you tired That much faster?" that would very much depend on the physical attributes and playing style of the player.

_________________
SU1 : Blade: Stiga Carbonado 45 FH: DHS H3 max blk| BH: Donic Barracuda max red
SU2 : Blade: Joola Rossi Emotion FH: DHS H3 max blk | BH:Donic Barracuda max red

What a noob. That would apply to the force on the paddle not the force applied by the paddle to the ball.
See this
http://en.wikipedia.org/wiki/Impulse_(physics)
The force depends on the change in momentum of the ball divided by the time, what TT players call
The change in velocity is computed using the COR formula posted by ttgame.


It is obvious you know nothing.
Where did you get that non sense force equation? Find a reference and don't come back till you find it.


The COR is not irrelevant nor constant! Again where did you get this nonsense. ezio on mytt posted a link to a pdf that showed that the COR changes across the face of the paddle. Hence the term sweet spot.


Finally, you get something right.


Wrong again and you broke your right streak of one and you were doing so well.
The power available can be used to calculate the paddle velocity in a given time. The paddle speed does affect the speed after impact.


I don't care how it affects you. I play better, longer with more consistency, with paddles in the 160 -170 gm range.

I think HaggisV should make people back up their statements and do more to stop those that make antagonizing statements especially when they are so clearly wrong. HaggisV claims to be an engineer too and should know better. I wasn't going to bring this issue up again on this forum since there are few here that will not even try to understand the speed after impact and still question my engineering/physics abilities with being engineers themselves or references to back them up, I have to respond and the gloves are off for now on. At least there is one person backing up my statements about COR and how the mass has very little effect on the speed after impact. Those of you that are engineers should look at the formula for speed after impact and verify what I and ttgame are saying and then chose sides.

All of you that want to see the power in your paddle should simply burn them. You might be able to make some steam and power a Sterling engine.

_________________
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

look i'm no engineer but i do know that 2 planes can't bring down 3 buildings!

now my take on this power vs weight thing, the most powerful tennis raquet i have ever played with was actually quite light, around 260 gramms, which is around 80-100g less than what the pro's generally use. it's not just the total weight, it's where the ratio of weight is situated. head heavy will give more power. more area in a tennis raquet more power.

a good example of a light table-tennis bat is the joola kool blade, very light and superfast.

remember a table-tennis ball is particularly light, so using a heavy blade + rubber would result in little increase in ball speed.

a golf ball being alot heavier,i would believe making the clubface too light would reduce the speed of the ball. i did own once a very light carbon headed driver,i could feel an increase in clubhead speed and i could see a decrease in distance of around 5 metres!

and one other thing i dislike about heavy table-tennis bats, impossible to have a good b/h flick with a heavy bat, at least for me anyway.

I am not suggesting any theory here, just try to do the calculations so hopefully we will have some figure to compare. Please correct me if I have done any maths wrong pnachtwey.

Here is a formula that I found from wikipedia http://en.wikipedia.org/wiki/Coefficient_of_restitution



In this 'experiment' only the mass of bat (Mb) will change independently, and the velocity of the ball will change dependently.

Here are constants that I will use for this 'experiment'.

Ma = mass of the ball = 2.7g = 0.0027 kg
Ua = initial velocity of the ball = -10m/s(made up)
Ub = initial velocity of the bat = 5m/s(made up)
COR = Coefficient of restitution = 0.8 (estimated, as COR of table tennis ball and steel block is ~0.9 "The rules say that the ball shall bounce up 24–26 cm when dropped from a height of 30.5 cm on to a standard steel block thereby having a coefficient of restitution of 0.89 to 0.92." http://en.wikipedia.org/wiki/Table_tennis#Ball)

so the whole equation becomes:

Va = [(0.0027)(-10) + (Mb)(5) + (Mb)(0.8 )(15)]/(Mb + 0.0027)
Va = (17Mb - 0.027)/(Mb + 0.0027)

Mb(kg) Va(m/s)
0.16 16.55
0.18 16.6
0.2 16.64
0.22 16.67
0.24 16.7
0.26 16.72
0.28 16.74
0.3 16.76

Is this significant? I'll let you to decide

Welcome to corrections, just don't call me a noob

_________________

Yasaka Ma Lin Extra Offensive Cpen - Yasaka Shining Dragon - Yasaka Razka 9
Galaxy U2 Cpen - Galaxy Sun - Galaxy Moon

I don't care if you're right or wrong pnachtwey, but these are arrogant and be-littling statements, and we don't appreciate these here. People deserve to be treated with respect, even if you think they're wrong. If you can't do this, you're not welcome on this forum. I'm not going to warn you again.

_________________
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

What about the velocity the ball was struck at as hinted above? I think that would be a more significant factor in increasing ball speed especially if the weight difference was "insignificant". No!

So if you hit it with 1000 sheets of paper is it even faster? Not necessarily.

I've bought enough blades to know that there is an optimum weight for a blade, however that may vary depending on the strength of the player.

As we know sometimes manufacturers will make a freakishly light version of a blade and these blades are usually slow and weak feeling. Also sometimes a manufacturer will produce a blade that's heavier than normal and these blades can be unwieldy and sluggish, maybe because they're too heavy to handle.

But sometimes we get a blade that's just right and I doubt I'd hit a heavier one any faster.

_________________



The MNNB Blog has had some pretty amazing stuff lately. Just click this text to check it out. | My OOAK Interview
Table Tennis Video Links: itTV | laola1.tv | ttbl | fftt | Challenger Series | mnnb-tv

My whole set-up costs less than a sheet of Butterfly Dignics

Actual case;

Same blades, brand, thickness, rubber, etc. Both 1 ply blades. Both visually looked the same.

#1) 102g, Speed, OFF+.

#2) 72g, Speed, ALL+ or OFF-.

Huge difference in speed and feel.

Only difference, density of wood.

Here's the thing. I have the same rubbers on the Matsushita Pro Special (around 95gm) and the Stiga Offensive NCT (around 85gm) more or less. The Mat blade is heavier than the Stiga one even without accounting for the extra weight in rubbers (oversized). However, the Stiga is easily heaps faster.

No. It's less than 1% faster (as shown by ttgame and hclnnkhg), which is irrelevant and nonperceptible by human. So, when everything else is the same, the heavier blade is the same speed as lighter blade. It 's because of much smaller mass of the ball comparing to the mass of the bat (http://hyperphysics.phy-astr.gsu.edu/hbase/colsta.html - Elastic Collision, Massive Projectile)



That's correct. But it is in contrariety to your previous statement: "When everything else is the same, the heavier blade is faster."



In fact, 2 blades with the same plies, same material, but different weight should play the same.
Probably none of us has tried 2 blades with the same plies, same material, but different weight because if you have 2 blades of same brand, thickness, rubber, both 1 ply blades, visually the same and one is 102 g and another is 72 g (like hookshot has) then the difference is in the blade material and COR of the blades is not the same. If they are same thickness, head and handle size then heavier blade must have more dense wood, greater COR and therefore these are not comparable.
72 g blade should have proportionally smaller head and handle and then it would play the same.



It's not Pnachtew's formulas, its physics of collision.


My conclusion is that we have to distinct what we are talking about.

a) If the question is whether the EQUAL SIZED heavier specimen of same blade model is faster, then the answer is - yes, because it has different inner structure (denser, harder wood), greater COR, more rebound, all fits in formula

b) If the question is whether the BIGGER SIZED heavier specimen of same blade model is faster, then the answer is - no, because significant weight difference (10%) doesn't efect resulting ball speed (less than 1% increase in speed is irrelevant)

Cause of all this misunderstanding is because we have 2 different standpoints. pnachtwey represents standpoint b) and he is right. Some others represent standpoint a) (because it's most common case in real table tennis world) and they are right too.

Nobody is wrong, we are talking about 2 different things here.

To avoid such misunderstandings people should be more precise.

Hello dajdosta,
Yes, you are right. You are the first to distinguish between the two sets of conditions.

The reason for the controversy I think, is most people are thinking like my example. My example is very precise. It is real. My friend and many others saw the difference in speed of blades and yes, the difference is caused by the less dense material. Since most blades are about the same size, why would anybody think that the question involves a bigger blade if it is heavier? They are thinking the same size blade and heavier. (real world)

Different material, (less dense material) is the same as comparing two different blades, say a five ply and a seven ply from an engineering standpoint.

Are we discussing this based on the theory that two piece of the same type of wood,with different densities, are identical constructed? But they ARE different! confused

_________________

Yasaka Ma Lin Extra Offensive Cpen - Yasaka Shining Dragon - Yasaka Razka 9
Galaxy U2 Cpen - Galaxy Sun - Galaxy Moon

I think most people understand what speedplay and I are saying about the same blades (brand, model,etc) that have different weights but are the same size. If this continues, I would suspect dajdosta (Post #1) and pnachtwey are one and the same or they work togather. They argue a fine line for the sake of arguement.

OK I get it now, and I understand that it is very difficult to be polite when arguing



But it is faster, and even if we can't FEEL it, it will make a difference as you will hit the ball at a different angle, or you will miss it by few millimetres.

_________________

Yasaka Ma Lin Extra Offensive Cpen - Yasaka Shining Dragon - Yasaka Razka 9
Galaxy U2 Cpen - Galaxy Sun - Galaxy Moon