@Pnachtwey
If youthinks that he is looping the robot ball, clearly there is someting mistaken about looping. Once again it's only because the contact point is ultra high that the ball is going over the net (I could get this beckspin ball past the net even without moving my racket, yup with a static racket, it would be ez, same are some adjustments anyone here will be able to falt hit the ball, you just have to adjust the racket angle).
It really looks like flat hits on underspin ball, the ball is going down right after the ball contact. With the same technique it will be impossible to loop this ball with a contact point under the net.
Pnachtwey you should try the same thing but just waiting for the ball to be under the net and try to loop it back by giving it an arc, with this level of underspin (150+rev/s) just to understand what we are saying here first. Then for improvement, a good thing will be to do exactly the same exercice as we see on the second video with his play mate..........but doing it seriously, meaning huge backspin on the serve, if possible huge backspin + short serve (for more advanced players, requires far more touch than huge backspin + long serve) and then a 3rd ball FH topspin.
Here I don't see the point, the serve is long without spin, the return hardly has any backspin and then a FH topsin that is not even meant to be a winner.......there much better usage of precious training time to be done !!!!
The serves have to be REAL serves, meaning that you concentrate on it to get maxium backspin (long serve if you cannot achieve short serve with huge backspin), this way you also benefit of this training to get also better serves. The training partner takes the ball right after the bounce to input huge backspin (the more backspin you put into your serve, the more backspin yopur partner will be able to input also, while keeping the ball low) into a low a long ball into your FH and then you execute an opening FH loop or killing 3rd ball attack. Repeat it hundreds of time.
This will be truly productive.
And, one more thing, there is no meaning executing 3rd ball attack drills if you don't have, at least, a huge backspin long serve, really, there is no meaning in it.
Table tennis is a constructive sport, its not like I can begin to train someone to do killing 3rd ball attacks if this guy doesn't have the serve skills to benefit from this traing. You won't be able to do 3rd ball FH attacks if your serves are so bad that it is easy to attack your serve.
Most of time, the coach instruction, during those type of exercices, is to attack right away if the serve is long for example....
Also, 9mm balsa core, please don't tell me there is also carbon in it, like a Joola Kool or Yinhe T11, what you are lacking the more right now is touch, not even speaking about technique or anything else, it is to FEEL the ball, to feel when you are giving spin (or not), to feel when your contact is good (or not), to FEEL. This is far more important at your level than the astronomical power of a 9mm balsa core. Get a 5 ply 6mm tick allwood with a lot of flex and if possible a ton of feedbacks (vibrations, sound), something like Stiga Offensive Classic.
Pnachtwey, you are right about the fact that when you topspin a backspin ball, the ball will always rotate (in the referential of the floor), but Carl is not an engineer and what he describes can be wrong if taken litteraly but it is so true when taken from a lambda tt player with a very good feeling.
Carl is describing his feeling, he has the feeling that when he executes a very good stroke, he can "grab" the ball. As I explained, here is just the feeling of being able to deform the rubber, maximizing dwell time and spin, the feeling you get when you have good arm/wirst accelaration. He wanted to explain that there is much more than your simple way to see physics in table tennis and he's done it based on his feeling (and I'm sure he has a pretty good one, because is table tennis "intuition" based on his feeling actually matches very often the physics, even if it's not 100% accurate, but dude......Carl is not a physics nerd and an engineer like I am, or you are, he tries to describe his FEEL with mere words, thats all).
Certainly the same feeling Schlager gets on all his serves, the amazing spin is not created by raw bat speed, it is creating by a combination of very big but very short acceleration (not long enough to reach very high bat speed, as I said I think anyone here can reach higher bat speed on a pendelum serve than Schlager on most of his serves, but nobody here will come close to his level of spin). This way, Schlager is able to maximize dwell time and to deform his rubber far more than anyone of use.
This feeling, to deform the rubber much more than a usual stroke would, even on serves, has been described many time with his own words by Carl.........for example Der_Echte will call it by the famous expression "Bang Impact", a compination of "Hand pressure mastery" and huge acceleration. Werner Schlager, the Elite, is able to get this "bang impacts" even on serves.
But I trully think you lack feeling, with more feeling you will understand far better what Carl is saying, feel is the alpha of table tennis, the omega is the touch and I think it is very very difficult to get a good technique without good touch and feeling.
To me, it looks like you are wanting to overcome your lack of feeling and touch by the usage of low grade physics, and judging from the video it doesn't look like this is a good trade for your improvement, for example you think that you are doing topspins against the robot backspin, it's not true, there is no spin in your ball, you can't feel it but you can at least SEE it, your balls have no spin, just watch the video.
See this video of Freitas touch and feel :
See what he is doing at 1:15 "the backspin catcher". A guy like Carl will instantly understand what Freitas is doing and the level of touch behind it, based on his own feeling. And you won't understand this based on low grade physics applicated to table tennis, because like many scientist would do and has you said, you will consider the dwell time as few milliseconds and thuus........somehow a constant parameter. You even wanted to "expose" the "myth" of long/shord dwell time....etc....but man, a guy like Carl will instantly understand what Freitas is doing the "backspin catcher", indeed he is minimizing dwell time as much as possible, so much that the ball is keeping its backspin after multiple contacts with the rubber, try to guess what will happen with a longer dwell time, try to do it yourself and try to FEEL the ball, the dwell time...etc..., there is now way to understand it with low grade physics once again, even introducing a friction coeficient....etc...won't help you here.
Now I understand why you wanted to "expose" the "long/short dwell time myth" on your famous topic, I trully think that you lack touch and FEEL, and into your hand there is no short or long dwell time blade/rubbers/whatever and you trully believe(d ?) it was a myth. But it's not a myth, you just can't feel it.