Dwell Time and Throw Angle: Are These Terms Even Useful

[langel]

One has to adapt to every set-up.
If I can adapt to a setup that you describe as difficult or even impossible to control then most people should be able to do it.
Feelings are an individual thing.
My very first time playing ping pong all we had was a 1mm layer of cork on either side of the blade, i am sure that this would feel quite different to play with now 😁

That's not the answer to the questions.
It's just a statement anyone can do.

Please describe the differences, style orientation, speed margins, spin capabilities, over the table, close-mid-longer distance, preferred depth of return, arc height, touch-hit-drive preferences, at what height you prefer to take the ball with those different set ups, and at what speed, spin and distance circumstances - under the table level, table level, net level, open window, ascending, descending, etc.
Can you say something in regard of the thread topic, for any of your different set ups?

 

[lodro]

Langel,
this thread was just a tease, it virtually stopped with post #5 and #6
you might be the only one still expecting a proper definition and best of luck to you

post #5

Originally Posted by lodrowell i ain't sure if I can use this kind of language here but i shall give it a try:
"""""Fer ****s sake .... not again !!! """ 🤣🤣🤣


post #6
brokenball replied:That is what I think when some one mentions throw angle and dwell time.
Yeah, lets ban the words "throw angle" and "dwell time". Let the topics die.
At least the myths will not be spread. No one can define them or truly understand them.

Wouldn't you like to hear about the astronaut and trampoline? Oh well. I am done

 

[brokenball]

Dwell time and throw angle are not feelings. Dwell time, contact time, is real. The "touchy feelly" time is a feeling.
Throw angle is a term that people can't define in a consistent way and is subject to different opinions depending on the player. Not very useful.
People are adaptable. They can adjust to different paddles.

It is pop corn time.

You have been saying this for years and it is absolutely false.

What was absolutely false? Accusations out of context p!$$ me off. Show us! You can't. You destroyed the evidence.
Dwell time is about acceleration and force. I####s like grandpa, a forum member, can't get it right then grandma won't either. Sorry Gozo.
What was I supposed to call someone that insisted acceleration doesn't cause force?
BTW, grandpa probably changed his name after realizing he screwed up big time.

You were banned at a time when a thread where the subject was dwell time and you were pontificating.

pontificating? Isn't that what you asked me to do above?

If I may add, please, pretty please explain in language even a grandmother can understand. Not all of us are engineers / scientist / astro-physicist etc. Thank you.

This isn't possible. However, I did expect at least ONE person to understand if they're any true engineers or physicists around.

I have a YouTube channel about control theory. Most people bail after 3 minutes because they don't understand the math. That is evident from Goolge analytics. That isn't my problem. That is their problem. The ones that understand like my videos as I bring new insights that they aren't in the books. I made the videos for the rare few that want to and can understand.

I bet this forum is still talking about dwell time and throw angle years from now. Nothing is learned.

 

[langel]

AAaaaHhhhRrrrr!

Got It!

Ok, I'm going to tramp with Trump 'bout the Musk's Roadster rusted rollers.

And, as I often use to say:

 

[langel]

Never question Bruce, ....boys

 

[UpSideDownCarl]

pontificating? Isn't that what you asked me to do above?

Absolutely. I did. But most of what you did was talk about people you have bad opinions of and how you made them look bad….or something.

But, if you are actually willing to do the work, ignore all the stuff that other people say and just talk about what “Dwell Time” (contact time of the ball on the blade face) IS and how it is different from the Vibrations from the blade (what you feel in your hand) that will last much longer than the actual contact time. And how the contact time is so short that the rebound of the blade could not cause the ball to go faster because of how much slower the flex is than the contact time: I think it would be great to have you lay those things out.

Also, if you explained what you think the possible range of meanings that people seem to lump together as “Throw Angle” and what things they may refer to as separate issues, I think it would be worth it.

And, the thing you presented about how a shorter dwell time with a quicker sponge/rubber rebound could actually create more spin rather than less, I think that is really good information.

I just think it is unfortunate that you get bogged down in trying to make other people look bad (which seems to make people resent you) when, if you just presented information and let go of trying to put others down, people would see you have a lot to offer.

But when you go at all the people you feel you need to avenge yourself against instead of simply presenting good information, in the end, it causes people to not want to interact with you.

When you do simply present the good information that you have because of what your actual expertise is, the information is invariably excellent.

So, feel free to provide the information only you can. But please stop the personal attacks, especially ones about people from other TT forums.

 

[langel]

Dwell time and throw angle are not feelings. Dwell time, contact time, is real. The "touchy feelly" time is a feeling.
Throw angle is a term that people can't define in a consistent way and is subject to different opinions depending on the player. Not very useful.
People are adaptable. They can adjust to different paddles.

It is pop corn time.


What was absolutely false? Accusations out of context p!$$ me off. Show us! You can't. You destroyed the evidence.
Dwell time is about acceleration and force. I####s like grandpa, a forum member, can't get it right then grandma won't either. Sorry Gozo.
What was I supposed to call someone that insisted acceleration doesn't cause force?
BTW, grandpa probably changed his name after realizing he screwed up big time.


pontificating? Isn't that what you asked me to do above?


This isn't possible. However, I did expect at least ONE person to understand if they're any true engineers or physicists around.

I have a YouTube channel about control theory. Most people bail after 3 minutes because they don't understand the math. That is evident from Goolge analytics. That isn't my problem. That is their problem. The ones that understand like my videos as I bring new insights that they aren't in the books. I made the videos for the rare few that want to and can understand.

I bet this forum is still talking about dwell time and throw angle years from now. Nothing is learned.

My upper postings were addressed to Lodro, you have posted before me.

About your statements - generally I would agree, but with a little bit of opaque.

Dwell time is an objective feature and Throw angle is objective too.
Dwell can be controlled by the player and Throw angle can be controlled by the player.

But in reality the Throw angle is a much better expressed natural feature of the rubber, dependant to the ball rebound angle it can provide in different spin/speed situations. That's why most players usually ask what would be better for arc, loop, lifting, chopping, pushing, blocking, brushing, smashing, etc. Controlling the throw angle is a must.

Dwell is objective too, but it's on a higher level of abstract for the majority. It's always there, but controlling it on purpose is a challenge, needing at least a bit more experience than controlling the throw angle.

 

[Gozo Aruna]

My unscientific understanding of throw angle & dwell time.

1) Throw angle: Suppose a certain ball flight path or trajectory is desired and remain constant. A low throw angle rubber requires a more open up bat angle to create that flight path vis-a-vis a high throw angle rubber where the bat angle must remain more closed compared to a lower throw angle rubber to maintain that similar flight path.

Now, on to the application part which is more tricky. If my definition above is correct, then to me, a low throw angle rubber is suitable for player who loves to create slow spinny topspin or should a fast low loop is desired, then a more powerful FH topspin is required compared to a high throw angle rubber.

On contrary, a high throw rubber, if you open your bat more, then the ball will arc very high and may land away from the table. That is why you need to close the angle of the bat more. It would appear that a high throw angle rubber may have a greater margin of error and more forgiving.

So then what is the benefit of low throw angle then? I suppose if you have the right technique to hit very powerfully a topspin, the ball will lunge forward a great speed and the bounce of the table is low, almost skidding / skimming on the table surface, making it that much more difficult to return by your opponent. It is a double-edged sword. You have to weigh the risk to reward factor for using a low throw angle rubber.

2) Dwell time is the time it takes for the ball to come in contact with the rubber surface and leaves the rubber surface.

On dwell time, a longer dwell time, by my logic means that the ball eat more into the rubber giving higher opportunity to create higher rotation. However, we see that in real life that is not the case as many pro players can generate immense ball rotation using hard rubber with low dwell time. This, I leave it to the expert to explain the discrepancy.

Thank you for your time.

 

[Manto76]

Hi Brokenball,

Hope you had a nice weekend.

I wonder if the problem here (ie. in this conversation) is not so much a scientific one as it is linguistic. What do I mean by that?

Well, it seems to me (apologies in advance if I've misunderstood you) that you make the assumption that when folks like me talk about 'dwell time' or 'throw angle' (or similar) that we mean to do so in such a way as to describe something with scientific precision - hence your requests for somebody to provide a descriptive formula.

But scientific language is not the only way to communicate. In fact, it's not the way people communicate in normal conversation most of the time. An equally valid way of communicating is in phenomenological language; which is language that describes phenomena (ie. things/experiences) as they appear/seem to those observing/experiencing them. For example, when I say that the sun rose at 6:15am this morning, I am not claiming that that the sun in fact 'rose' at all. From a scientific perspective that would be a false assertion as the sun does no such thing. What I am claiming in the statement 'the sun rose at 6:15am' is that, from my perspective as an observer on earth, it appeared to me that sun rose at 6:15am.

Likewise when I say that, for example, Blade X gives a higher throw angle than Blade Y, I'm describing my experience with those two blades. That fact that I describe the comparative experiences in that language, rather than in the language of scientific formulae, doesn't make my description any less helpful to others trying to get a sense of whether Blade X or Y might be better suited to them.

Of course, the downside of this is that different observers might report different (or even contradictory) results. But this, then, is a reflection of the relative expertise of the reporters of those experiences. It is not a fault inherent to phenomenological language. In fact we expect differences to be reported, and we gain confidence in the matter by aggregating the reports of multiple people. This is why sites like RevSpin are actually really helpful; they report the aggregated experiences of multiple people on things like 'throw angle', 'gears', 'control' etc. Of course no one is claiming that a table tennis rubber actually has 'gears' (in the mechanical sense of the word). Nevertheless we all know what someone means when they say that Rubber A has more 'gears' than Rubber B - and we're happy to hear their observation (or the aggregate observations of many people) even without a formula to describe (scientifically) how the 'gearbox' of a table tennis rubber (or blade) works.

In summary, multiple users reporting their experiences on the same phenomena is really helpful - and quite fun - even in the absence of descriptive formulae. On that point, I think we all know what we mean by 'dwell time' and 'throw angle' and 'whip effect', but here are my attempts at descriptions of those phenomena:

• Dwell time is the sensation of the ball remaining on the rubber/blade.
• Throw angle is the tendency of a rubber/blade to launch the ball at a higher/lower angle from its face.
• Whip effect is the sensation that a blade flexes slightly and recovers to a neutral position very quickly at the point of impact with the ball in the process of a powerful swing.

I find the aggregated reports of other people on these phenomena helpful and, more often than not, if I try the blade/rubber myself, my own experience seems consistent with that of the majority. I hope my own contributions to the aggregate feedback on the blades/rubbers I try will likewise be helpful to others - hence I'll keep using those descriptions!

Hope that helps; if not, feel free to ignore me!
Manto

 

[Corey]

Most players don't have enough tt level to truly understand what these terms mean at all. Might as well spend more time on improving the techniques than discussing something so vague 🤣

 

[lodro]

maybe the problem has arisen from the fact that there are always 2 components involved .
The first one is the one which , given the correct sophisticated machinery IS MEASURABLE
The second one will apply the very moment a racket is taken from a solid rest and put into the hand of a human - this is the "TOUCHY FEELY PART".

Can everybody live with this ?😁

of course, frankly my dear.................................

 

[brokenball]

There seems to be missing threads.
The problem with understanding dwell time is one needs to understand how acceleration and force work.
If you stand on a trampoline you will cause it to sink a bit until the force it generates is equal to the force due to your mass and acceleration due to gravity.
As long as the force generated by the trampoline upwards is equal to the force generated by the mass and gravitational acceleration are equal, there is no acceleration or motion.
Effectively your dwell time can be infinite.

There are two forces. A force generated by the springs of the trampoline ( rubber ) and the force of the person ( ball ) x acceleration due to gravity.
This is Newton's equal but opposite forces law, the 3rd one.

Now assume you are an astronaut in space and you have a trampoline for exercise. Assume the space ship is accelerating at 9.8 m/s^2 which is the same as 1 g. If the astronaut stands on the trampoline, it will sag the same amount as it did on earth. There is where my original thread got derailed. A person that called himself grandpa, claimed that acceleration doesn't cause force. However in the astronauts case the force that the trampoline applies to the astronaut is equal to the force that is due to his mass time the acceleration of the space ship. Since the two forces are equal there is no acceleration relative to the trampoline or spaceship. Therefore the dwell time is effectively infinite.

Ideally, the best way to create artificial gravity in space is to accelerate the spaceship at a constant 9.8 m/s^2. However, this is not practical yet because we don't have spaceships that can accelerate at 9.8m/s^2 for very long. Eventually, the spaceship will run out of fuel and the space ship will stop accelerating.
Now the trampoline is still depressed and pushing on the astronaut but the force of the astronaut on the trampoline is now 0 because his mass times acceleration is 0. Now there is a net force and the trampoline will accelerate the astronaut to the ceiling or overhead. The dwell time ends.
Likewise, you can;t accelerate the paddle very long so the force generated by the compress rubber, deformed ball and blade will exceed the force the ball exerts on the rubber so the ball will accelerate away from the paddle and dwell time ends.

This time I got a little further because there is no idiot saying acceleration doesn't cause force. Anyone that has sat in a plane during take of on in a fast car knows acceleration forces them back into their seats.

There is more but this is enough for now.

Hopefully, Gozo's grandmother understands but I doubt it.

The real question is how fast must the paddle accelerate to keep the ball on the paddle to extend dwell time? Remember, two forces must be equal.

BTW, the movies like to show people in space stations or space ships walking around in spinning rings. This will work sort of. What they don't show you in the movies is that water flowing out a faucet will not fall straight down. A dropped ball will not fall straight down. Throw a ball up and it won't go straight up or come straight down. This would make playing TT interesting on a rotating space station. If the table is aligned, parallel, with the axis of rotation, the ball trajectories will curve. Think about this. What if the table is aligned with the angular velocity of the spinning space station?

Think!

 

[lodro]

please take in to consideration that this is written by a brain-damaged person !

When they show on TV people in space, they are always floating around in the cabin.
Looks like they are weightless. So, if the weightless people stand on a trampoline would they
really still bend it ?
There is no up and down in space of course.

 

[UpSideDownCarl]

please take in to consideration that this is written by a brain-damaged person !

When they show on TV people in space, they are always floating around in the cabin.
Looks like they are weightless. So, if the weightless people stand on a trampoline would they
really still bend it ?
There is no up and down in space of course.

Lodro:

1) If I am asking him not to insult others, why do you think it is okay to insult him?

2) What you say about weightlessness in space shows you did not pay attention or understand what BrokenBall was describing.

 

[lodro]

Lodro:

1) If I am asking him not to insult others, why do you think it is okay to insult him?

2) What you say about weightlessness in space shows you did not pay attention or understand what BrokenBall was describing.

???????????????????????where is the insult ??????????????????????
It is myself I describe as brain damaged not Brokenball
and yes, it is absolutely possible that i did not understand what he is describing .
As a matter of fact I have no idea why he even takes us out into space to play ping pong

 

[UpSideDownCarl]

???????????????????????where is the insult ??????????????????????
It is myself I describe as brain damaged not Brokenball
and yes, it is absolutely possible that i did not understand what he is describing .
As a matter of fact I have no idea why he even takes us out into space to play ping pong

Okay. Sorry. I thought you were referring to BB.

He describes the acceleration needed by a ship in space to create a force equal to the force of gravity on earth.

I thought the description of forces acting on the person and the trampoline in outer space was a good way of getting people to visualize how different forces could be acting on the trampoline or blade face.

 

[brokenball]

Lodro:

1) If I am asking him not to insult others, why do you think it is okay to insult him?

2) What you say about weightlessness in space shows you did not pay attention or understand what BrokenBall was describing.

USDC, I know Lodro was not insulting me. He was insulting the brain-damaged film makers that don't know how reality works. The film makers do have a hard job. The TV series expanse does a pretty good job of making things realistic.

Lodro does bring up a good point. The brain-damaged film makers get away with it because most viewers don't know the difference. Gozo's grandma wouldn't know the difference. Most people haven't even thought about it. It is all eye candy.

There is a scene in Babylon 5 where Kosh saves Sheridan when the train or shuttle blows up. You don't see the back ground rotating.

Back On Topic.

It seems we agree that two forces need to be equal to extend dwell time. What is the force a rubber exerts on a ball during impact?
This must be match by the acceleration of the paddle times the mass of the ball. Since the ball weighs little, the acceleration must be very high to match the force the rubber exerts on the ball. We need to know the force the rubber exerts on the ball. We know the mass of the ball so it is possible to calculate the the required acceleration.

"Do you want to know more" Starship Troopers.

 

[lodro]

Do you want to know more" Starship Troopers.


Neee, I am good. Let me know though when you are back from space 😁
In the meantime, back here on earth, dwell or no dwell, when the incoming balls pop off my racket too long, I will turn it a bit downwards and
when all incoming shots seem to go into the net I turn the racket a bit upwards .
Being brain damaged, I have to keep it simple 😁

or with the words of the late great Franky Zappa : " I know when i am licked .............all over" 😃

 

[BryanY]

Slightly different question here. When the outer ply of the blade compresses due to ball impact. Does the outer ply kick the ball out when it decompresses? Or has the ball already left the bat once the outer ply finishes compressing?

(I’m not talking about the the core of the blade flexing, I’m talking about the outer ply compressing and decompressing.)

 

[zeio]

The floor is all yours, literal engineer. I'm all ears.