The choice of balls was not possible ,since i head to use the spinsight balls for measurement obviously.
Unfortunately the test had to be changed a little from what i planned initially due to the limitations of my setup.
So my Butterfly robot did only ever create 50 rps on top spin (set to +6 spin +9 speed), so this is more likely a heavy topspin serve than a real loop.
What did i test:
- against topspin +50rps topspin with speed of 20 km/h
- block with inverted (blade angle nearly vertical, perhaps closed by 5 to 10°)
- block with pips out (blade angle nearly vertical perhaps opened by 5 to 10°). Here i had to take the ball earlier for it to even pass the net
- against backspin -43rps backspin with speed of 15 km/h
- push/lift only with inverted
- push block (go through the ball) with long pips
- counter block (counter through the ball with open blade) with long pips
- push/chop with inverted and pips out trying to create maximum backspin
The blades of the first 4 inverted rubbers were Nittaku Acoustic, the Blade of the Bomb Talent/Donic Coppa was a Spinlord Ultraspin, the other blade i did not see any name on it.
| Incoming Topspin Ball 50rps/20km/h | Spin after Block (+ is topspin/ - is backspin) | speed in km/h |
|---|
| Block with FastArc C-1 | +16 | 15 |
| Block with Stiga DragonGrip55 | +13 | 14 |
| Block with Glayzer 09C | +18 | 16 |
| Block with Battle 2 Gold Prov | +11 | 13 |
| Block with Donic Coppa | +7 | 13 |
| Block with Rasanter R37 | +11 | 15 |
| Pushblock with Bomb Talent OX | - 36 | 11 |
| Pushblock with Spinlord Dornenglanz OX | - 36 | 12 |
What was really frightening is that the amount of spin coming back from a passive block was so low, considering how much spin was "generated" or coming back to the opponent for the long pips rubbers with basically "no own skill", just holding the racket there.
Now the spin values for returning backspin balls.
For longpips i had to pushblock (push and go through the ball with an open blade) for it to pass the net.
For inverted i would only lift the ball.
Incoming Backspin Ball
-43 rps with 15 km/h | Spin after Action (+ is topspin/ - is backspin) | speed in km/h |
|---|
| Lift the ball with Glayzer 09c | - 20 | 16 |
| Chop the ball with Glayzer 09c | - 57 | 23 |
| Pushblock with Bomb Talent 0X | + 17 | 15 |
| Chop with Bomb Talent 0X | - 22 | 11 |
| Pushblock with Dornenglanz 0X | + 20 | 15 |
| Chop with Dornenglanz 0X | - 18 | 15 |
| Push Counter with Dornenglanz 0X | + 29 | 23 |
Testing a little with the Dornenglanz i wanted to find how to return the ball more aggressively and a push counter (basically countering through the ball with an very open blade face) resulted in quite menacing topspin attacks that were low and relatively fast. Balls that you would probably only be able to generate if you had a very good and spinny backhand or forehand flick.
So all in all a little disappointing that i was not able to get higher incoming topspin rotation on my robot, but i did what i could with this setup.
At the very end i wanted to check how much backspin was possible when serving with 0x longpips and i had real trouble even clearing the net, because i had to chop really heard for it to even reach the net. When i finally did i was able to do -19 (backspin) and 9 km/h with the Dornenglanz and -23 (backspin) and 11 km/h with the Bomb Talent.