Spin and speed comparison of rubber/ply [video]

[palguay]

I plan to create videos examining various rubbers' spin and speed effects. Here are the initial videos in this series. Once we get the basics right, we can go to different clubs and try different combinations. Starting with Dignics 09c and Nittaku Fastarc G1 on a Petr Korbel ply

Let me know if you want me to look into something particular or what data to collect, which might be a helpful reference for others in the future.

Introduction

Speed Comparison Dignics o9c vs Nittaku Fastarc G1

 

[jk1980]

I am very interested in this kind of experiment

 

[palguay]

I am very interested in this kind of experiment

Same here . Hopefully we can understand this better as we do a few more video's and this might be a useful parameter for people to track and work on improving their speed, spin

 

[Tony's Table Tennis]

Good work.
I always wanted to make some videos, but I just don't have the skills and time to fit it in. So well done!

Some advise:
1) get a microphone
2) position your bat at an angle (can use different angles and have more data to use)
2.1) with number 2, can also place them for underspin balls

Why I suggest angles - since this will be more realistic to actual game play. At such angles are how the pips structure + sponge are designed by the makers.

keep up the good work

 

[TensorBackhand]

So your test is saying 09c is faster than G1? I was pretty sure G1 wouldve been faster.

Can you do a test of dignics 05 vs hammond Z2?

 

[brokenball]

This is very good. It takes a lot of time to do testing. I know.
I suggest you don't try to please the US crowd with measuring units like rpm and mph. Treat this as a physics lab and use units like meters per second and revolutions per second. Things happen quickly in table tennis so seconds is a more appropriate time base than hours. Even radians per second would be good for speed since calculations like that for the Magnus effect use spin in radians per second. I think the MKS system will be more intuitive to the TT players.

With the setup you have, it will be difficult to get accurate measurements but it will be possible to compare rubbers.

Watch this YouTube channel. Many of the videos are about 10 years old.

https://www.youtube.com/@PathfinderPro1

Also note, he used a camera that could record 1000 FPS. I have a camera that can record 38000 FPS ( notice the frames frequency has a time base of seconds, not hours ). The problem will be lighting which limits effective FPS to about 2000 FPS. 5000 FPS would be nice but then lighting must be very intense.

I can see you can compare trajectories which is very good. Don't rely on the data for just one ball. The robots are consistent relative to people but they aren't that consistent.

It would be great to have data at 1 millisecond intervals. Speed and spin. I use to count the number of frames for the ball to travel the width of one ball and the number of frames it takes the ball rotate one revolution. This was many years ago. I hope there is software to make this go faster.

A limitation of many cheap robots , like my Newgy 2050, is that the spin is proportional to the speed. That hurts the ability to test different spin to speed ratios.

I will be watching.

 

[latej]

Let me know if you want me to look into something particular or what data to collect, which might be a helpful reference for others in the future.

Great job, a lot of work.

Why does the trajectory of the balls (red, blue) differ consistently already before the contact with the bat? I'd expect them to be "statistically" the same. And then we would see the difference in rubbers, after the bat contact.

But if the "red" balls already hit the table more close to the bat with 09c, than the "blue" balls for the G1 - it alone makes a difference in the trajectory after the bat contact.

 

[lodro]

But if the "red" balls already hit the table more close to the bat with 09c, than the "blue" balls for the G1 - it alone makes a difference in the trajectory after the bat contact.

Absolutely.
The "incoming angle" will naturally influence the "outgoing angle".
The fact that the balls hit the table at a different place also indicates a different speed.

 

[igorponger]

As per usual we learned sponge trampoline effect by the standard Schob impact test. So now, Tenergy proved below to the best in terms of rebound energy. The rubber of topmost is..... Schhhh. For commercial reason we are bound to abstain from giving true numbers, sorry.

 

[palguay]

Good work.
I always wanted to make some videos, but I just don't have the skills and time to fit it in. So well done!

Some advise:
1) get a microphone
2) position your bat at an angle (can use different angles and have more data to use)
2.1) with number 2, can also place them for underspin balls

Why I suggest angles - since this will be more realistic to actual game play. At such angles are how the pips structure + sponge are designed by the makers.

keep up the good work

Thanks for the suggestions, will try out these in later video's

 

[palguay]

This is very good. It takes a lot of time to do testing. I know.
I suggest you don't try to please the US crowd with measuring units like rpm and mph. Treat this as a physics lab and use units like meters per second and revolutions per second. Things happen quickly in table tennis so seconds is a more appropriate time base than hours. Even radians per second would be good for speed since calculations like that for the Magnus effect use spin in radians per second. I think the MKS system will be more intuitive to the TT players.

With the setup you have, it will be difficult to get accurate measurements but it will be possible to compare rubbers.

Watch this YouTube channel. Many of the videos are about 10 years old.

https://www.youtube.com/@PathfinderPro1

Also note, he used a camera that could record 1000 FPS. I have a camera that can record 38000 FPS ( notice the frames frequency has a time base of seconds, not hours ). The problem will be lighting which limits effective FPS to about 2000 FPS. 5000 FPS would be nice but then lighting must be very intense.

I can see you can compare trajectories which is very good. Don't rely on the data for just one ball. The robots are consistent relative to people but they aren't that consistent.

It would be great to have data at 1 millisecond intervals. Speed and spin. I use to count the number of frames for the ball to travel the width of one ball and the number of frames it takes the ball rotate one revolution. This was many years ago. I hope there is software to make this go faster.

A limitation of many cheap robots , like my Newgy 2050, is that the spin is proportional to the speed. That hurts the ability to test different spin to speed ratios.

I will be watching.

Thanks for the suggestions. Camera is a limiting factor as I don't have a good one to slow it down. I am looking around to see if I can get access to a good camera for higher fps. As you rightly mentioned lighting is also a big factor and in future we are planning to add a bit more when we get access to a better camera.

Yes there are good options for software these days, I will add video's for those later so that others should be able to replicate .

 

[palguay]

Great job, a lot of work.

Why does the trajectory of the balls (red, blue) differ consistently already before the contact with the bat? I'd expect them to be "statistically" the same. And then we would see the difference in rubbers, after the bat contact.

But if the "red" balls already hit the table more close to the bat with 09c, than the "blue" balls for the G1 - it alone makes a difference in the trajectory after the bat contact.

At this point I am trying to figure out camera, software and other things. Once we have the basics we should be able to collect better data to be able to answer some of these questions

 

[brokenball]

Bad news. I looked up Pathfinderpro's YouTube Channel since I hadn't viewed it in years. Two years ago Pathfinderpro made two videos asking if people were interested in how rubber hardness affects the ball and also how rubber thickness affects the ball. He didn't get much response. So he didn't make the videos. Apparently, no one really cares. People would rather believe in their myths than know the truth. Very

Camera is a limiting factor as I don't have a good one to slow it down.

Tieffenbacher didn't have a fast camera either so he left the lens open and used a strobe. Now you need a fast strobe.

Also, when testing rubbers, don't test them on a paddle. The paddle does affect the rebound. Get a hard wood cutting board to mount the rubbers on. The cutting board should be heavy and hard enough so it absorbs little if any energy. This way you are testing only the rubber, not the rubber and the blade.

 

[igorponger]

Butterfly Tamasu Rubber Matrix.
Those clever Japanese have already done whole work for us. Graphic presentation is the very best way for optimal selection from many rubbers, 30 and more. I love the Matrix layout so much.

https://butterflyonline.com/Templates/RubberSpecifications.pdf

 

[brokenball]

Butterfly Tamasu Rubber Matrix.
Those clever Japanese have already done whole work for us. Graphic presentation is the very best way for optimal selection from many rubbers, 30 and more. I love the Matrix layout so much.

https://butterflyonline.com/Templates/RubberSpecifications.pdf

Do you really believe the chart? What do the scales mean? Are they COR marked 0 to 100 instead of 0 to 1? If the scales are not COR then they are bogus. I can't believe the CORs would be that high.

 

[palguay]

Bad news. I looked up Pathfinderpro's YouTube Channel since I hadn't viewed it in years. Two years ago Pathfinderpro made two videos asking if people were interested in how rubber hardness affects the ball and also how rubber thickness affects the ball. He didn't get much response. So he didn't make the videos. Apparently, no one really cares. People would rather believe in their myths than know the truth. Very


Tieffenbacher didn't have a fast camera either so he left the lens open and used a strobe. Now you need a fast strobe.

Also, when testing rubbers, don't test them on a paddle. The paddle does affect the rebound. Get a hard wood cutting board to mount the rubbers on. The cutting board should be heavy and hard enough so it absorbs little if any energy. This way you are testing only the rubber, not the rubber and the blade.

Thanks, I will look into the strobe as far as the wood is concerned , it is easier to borrow other peoples equipment for now as I do not have the budget to get rubbers specifically for this.

 

[palguay]

Butterfly Tamasu Rubber Matrix.
Those clever Japanese have already done whole work for us. Graphic presentation is the very best way for optimal selection from many rubbers, 30 and more. I love the Matrix layout so much.

https://butterflyonline.com/Templates/RubberSpecifications.pdf

It does not give us any numbers in relative to other rubbers, also there is going to be bias. The way science works is that there has to be details given for others to replicate

 

[mightymouse]

Butterfly Tamasu Rubber Matrix.
Those clever Japanese have already done whole work for us. Graphic presentation is the very best way for optimal selection from many rubbers, 30 and more. I love the Matrix layout so much.

https://butterflyonline.com/Templates/RubberSpecifications.pdf

Given all the limitations mentioned above (for the Butterfly Tamasu Rubber Matrix), I see a pattern here as harder sponge yields more spin.

For example: Sriver FX vs. EL vs. ordinary Sriver.

Or Tenergy 05 FX vs. Tenergy 05.

I always think that with softer sponge you will have more dwell time, thus creates more spin. I guess it is the other way around.

 

[brokenball]

Given all the limitations mentioned above (for the Butterfly Tamasu Rubber Matrix), I see a pattern here as harder sponge yields more spin.

Wrong. Why would harder rubber generate more spin? Do you know why rubbers generate spin at all? Why not make the rubber very hard? Then harder again! Frictionless anti top sheets are almost brittle. Anti rubbers don't generate much if any spin.

I always think that with softer sponge you will have more dwell time,

Yes, so?

thus creates more spin.

What if the dwell time is infinite! Does spin increase? Put a ball on your paddle. As long as the ball is on your paddle the dwell time can be infinite in theory. Can you generate much spin with the ball on your paddle?

I guess it is the other way around.

Stop guessing and start thinking about what is really happening during contact! You are confusing the AI!

 

[merlin el mago]

You guys confused the dwell time with more spin because it's more easy to generate the spin with soft sponge.