How rubber properties affect throw

[hclnnkhg]

First of all, let's start with my understanding about 'throw'. In my mind, the 'throw' is the angle that the ball will leave the racket surface when you loop (or other stroke). The ball will leave a high throw rubber in tangential direction (in direction of brushing), whereas the ball will leave a low throw rubber almost perpendicularly with respect to the racket surface.

Now, how does the following properties affect the throw angle of a rubber?

1. Sponge thickness
2. Sponge hardness
3. Topsheet hardness
4. Topsheet grippiness/tackiness
5. Pimple structure - short and wide, long and thin etc.

 

[latej]

Obviously grip/tack helps, e.g. if you try a premade bat, you see no grip, can't take/drag the ball, we'd say low throw. That is somewhat obvious, let's leave it at that.

Now the racquet contains the blade, which is relatively hard, and the rubber, which is relatively soft. Let's say you hit FH topspin, the ball goes nicely deep into the rubber/sponge, and that increases the throw angle (imagine like there is more of the rubber around the ball to drag the ball), but if it goes too deep, a bigger portion of its momentum hits the hard blade, and that in turn decreases the throw angle. And the rest is just finding the balance for you...

So, on slow shots, the softer sponge allows the ball to go more in and the throw is higher, but on faster shots that same soft sponge will more quickly allow the ball to hit through to the blade, and thus will make the lower throw. So on FH where you generally hit harder you may want harder sponge, otherwise the softer sponge may feel like wasting energy.

If there is very little sponge, the ball will get more quickly to the blade, and the same logic applies.

If you have similarly hard rubbers, like e.g. Rakza X and Z, the tackiness of RZ helps to grab it, and it has higher throw.

About the pimples, I'd say the same logic due to softness/hardness as above applies. My own experience with H8-80 which has longer pimples vs H3 in the same hardness - it feels like H8-80 is more spin sensitive, it is a bit hard to describe. It forces me to go more into the ball, when blocking, to not make a mistake, so by accident it improves me, but I'll switch anyway when the season ends Cheers.

 

[brokenball]

You forgot stroke which is most important
I you just want to know about the properties of the rubber then read this:

https://deltamotion.com/peter/TT/199408014%20-%20%20Tiefenbacher%20-%20Impact.pdf

This document needs to be stickied until something better comes along.
no one measures angles and the angles are dependent on the stroke too
What you really want to know is the ratio of the tangential to normal COR which is dependent on the equipment and not the player.

 

[dingyibvs]

First of all, let's start with my understanding about 'throw'. In my mind, the 'throw' is the angle that the ball will leave the racket surface when you loop (or other stroke). The ball will leave a high throw rubber in tangential direction (in direction of brushing), whereas the ball will leave a low throw rubber almost perpendicularly with respect to the racket surface.

Now, how does the following properties affect the throw angle of a rubber?

1. Sponge thickness
2. Sponge hardness
3. Topsheet hardness
4. Topsheet grippiness/tackiness
5. Pimple structure - short and wide, long and thin etc.

Like others have said, it can depend on the stroke.

Grippy topsheet will give you a higher throw on brush loop as that's the only part of the rubber that's engaged.

Thicker sponge will give you higher throw on power loops. This one is easy to test as the same rubbers often exist in different thickness sponges.

Other stuff are more difficult to say, but it seems like as far as pimple geometry is concerned the thin pimples spaced wider apart results in lower throw based on the Tenergy and Dignics series.

 

[lodro]

Like others have said, it can depend on the stroke.

Grippy topsheet will give you a higher throw on brush loop as that's the only part of the rubber that's engaged.

Thicker sponge will give you higher throw on power loops. This one is easy to test as the same rubbers often exist in different thickness sponges.

Other stuff are more difficult to say, but it seems like as far as pimple geometry is concerned the thin pimples spaced wider apart results in lower throw based on the Tenergy and Dignics series.

and of course while all that is true the throw angle still also is heavily influenced by the speed,rotation etc of the incoming ball, how strong the hand is gripping the blade and of course the angles will change completely when the rubbers are fixed on to a new , different blade.
But of course you knew all that already 😁

 

[brokenball]

Like others have said, it can depend on the stroke.

Yes! I think you understand but too many think throw is a property of the rubber/paddle alone.

Grippy topsheet will give you a higher throw on brush loop as that's the only part of the rubber that's engaged.

Not quite. Obviously the rubber must grip the ball but most regular inverted rubbers are pretty good at that.
What helps with top spin is the ball stretches the rubber across the surface. Eventually the rubber will try to snap back to the normal position. This gives extra tangential motion to that of the stroke resulting in more spin.
The key is that the rubber stretches and then snaps back.

Thicker sponge will give you higher throw on power loops. This one is easy to test as the same rubbers often exist in different thickness sponges.

All things being equal, yes. Thicker rubbers allow the top sheet to stretch across the face of the paddle.
Likewise, a top sheet that is attached directly to the paddle would only be able to stretch has much as the pips will allow.

Other stuff are more difficult to say, but it seems like as far as pimple geometry is concerned the thin pimples spaced wider apart results in lower throw based on the Tenergy and Dignics series.

Yes, that is why it boils down to the normal and tangential COR as stated in the Tiffenbacher document.

I hope you understand.

 

[brokenball]

and of course while all that is true the throw angle still also is heavily influenced by the speed,rotation etc of the incoming ball, how strong the hand is gripping the blade and of course the angles will change completely when the rubbers are fixed on to a new , different blade.
But of course you knew all that already 😁

Yes, the angle is affected by thee incoming ball and that is the problem. There are too many variables that depend on other things than just the rubber/paddle.

If you just measure the normal and tangential COR of the rubber/paddle, then you have measurements where rubbers can be compared directly with out the influence of stroke and incoming speed. The goal is to reduce variables so an apples to apples comparison can be made.

 

[lodro]

just measure the normal and tangential COR of the rubber/paddle

Many tests have been made , shown and explained but none of them
has managed to define ''NORMAL" to my satisfaction

 

[brokenball]

Didn't anybody take geometry in high school?
"normal" is a 3D version of perpendicular.
The Z axis is normal to the plane defined by the X and Y axis.
The X axis is normal the plane defined by the Y and Z axis
Normal in the geometric sense.

Normal (geometry) - Wikipedia

en.wikipedia.org

Normal Vector -- from Wolfram MathWorld

The normal vector, often simply called the "normal," to a surface is a vector which is perpendicular to the surface at a given point. When normals are considered on closed surfaces, the inward-pointing normal (pointing towards the interior of the surface) and outward-pointing normal are usually...

mathworld.wolfram.com

Equation of a Plane - Point and a Normal - Maple Help

 

[lodro]

WARNING WARNING DANGER DANGER

If you want to keep your sanity do not, I repeat DO NOT click on
the above link re Wikipedia normal geometry

 

[lodro]

Didn't anybody take geometry in high school?
"normal" is a 3D version of perpendicular.
The Z axis is normal to the plane defined by the X and Y axis.
The X axis is normal the plane defined by the Y and Z axis
Normal in the geometric sense.

Normal (geometry) - Wikipedia

en.wikipedia.org

Normal Vector -- from Wolfram MathWorld

The normal vector, often simply called the "normal," to a surface is a vector which is perpendicular to the surface at a given point. When normals are considered on closed surfaces, the inward-pointing normal (pointing towards the interior of the surface) and outward-pointing normal are usually...

mathworld.wolfram.com

Equation of a Plane - Point and a Normal - Maple Help

yes buddy, we had all this stuff 60 years ago.
Some stay with it - some move on.
There are many other fields people can move into.
I give you an example from the book I am just reading now :


Hedonic preference refers to a stimulus property that is innately reinforcing or, speaking more colloquially, naturally rewarding.
Psychologists often use the terms primary positive reinforcer............

I hope I have not bored you