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DHS D40+ three star balls, good news
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Author:  d1244 [ 31 Jul 2017, 06:34 ]
Post subject:  Re: DHS D40+ three star balls, good news

I have been training with D40+ for a month now (with about 50 balls). I seem to get used to them, although at the beginning I wasn't that convinced.
Only 2 balls broke in the time (at the end of the month of playing with them) - so in terms of durability they seem quite good.
Not all of them are perfectly round - I think that for a 3-star ball roundness could be better. It is really noticeable during long training rallies - from time to time the ball just flies so strangely. I don't know - maybe it is related to some scratches that are on the balls, that appeared most probable after hitting with edge of the racket.

Undoubtedly, the backspin dies a lot quicker on the ball when compared to other plastic balls (non-ABS ones). On the other hand, by topspin the ball jumps further forward when compared to other plastic balls (non-ABS ones). The other balls tend to bounce high but not forward by topspin. You can easily test it yourself - just throw a ball horizontally against your racket (tilted circa 45 degrees - exactly the same way one usually tests the grip of the rubber) and let it drop on the table. I compared the D40+ with non-ABS Butterfly, Tibhar, Xiom and those other balls jump significantly less forward than D40+. I find it positive.

Author:  Lorre [ 31 Jul 2017, 20:11 ]
Post subject:  Re: DHS D40+ three star balls, good news

d1244 wrote:
Undoubtedly, the backspin dies a lot quicker on the ball when compared to other plastic balls (non-ABS ones). On the other hand, by topspin the ball jumps further forward when compared to other plastic balls (non-ABS ones). The other balls tend to bounce high but not forward by topspin. You can easily test it yourself - just throw a ball horizontally against your racket (tilted circa 45 degrees - exactly the same way one usually tests the grip of the rubber) and let it drop on the table. I compared the D40+ with non-ABS Butterfly, Tibhar, Xiom and those other balls jump significantly less forward than D40+. I find it positive.


Yes, I also found this to be the case. But is the jumping due to more spin or less? It must be less because backspin dies a lot quicker.

Author:  iskandar taib [ 02 Aug 2017, 12:57 ]
Post subject:  Re: DHS D40+ three star balls, good news

If the jump is forwards, then an increase in the jump means an increase in topspin. This whole thing about decay of backspin is interesting.. what would cause it, and why the differences between balls? The only thing I can think of would be surface texture, given that mass and diameter are the same across the three types.

Iskandar

Author:  d1244 [ 02 Aug 2017, 18:30 ]
Post subject:  Re: DHS D40+ three star balls, good news

DHS D40+ is made from the new material and the ball is much harder than other ones. Moreover, D40+ is much noticeably heavier. I would guess it is a matter of weight and surface texture combined making it jump further forward by topspin.

Author:  iskandar taib [ 02 Aug 2017, 21:03 ]
Post subject:  Re: DHS D40+ three star balls, good news

I don't see how surface hardness would affect spin decay. Production of spin, perhaps, but not decay of spin. And I don't see how it could be "much noticeably heavier", there are limits and tolerances for weight.

Is the ball noticeably smoother or rougher than the others? The way it bounces on the table might actually have to do with ball-table interaction rather than actual spin. Hardness might affect this.

Iskandar

Author:  d1244 [ 03 Aug 2017, 23:09 ]
Post subject:  Re: DHS D40+ three star balls, good news

The tolerance for the weight is 2.67 - 2.77 g and as Baal checked they weigh 2.76 g, and I can easily notice that when switching to other balls (these other feel lighter).
I mentioned surface texture in relation to the further jumping by topspin. Now I wonder, whether it is still reasonable - backspin dies quicker and topspin jumps further forward. That's why I wrote that I only guessed. Nevertheless the above still holds - only the reason is unknown.
By the way, I just looked at various balls and it is hard for me to tell the difference in textures (maybe apart from Butterfly G40+, which is clearly smoother).

Author:  iskandar taib [ 08 Aug 2017, 00:18 ]
Post subject:  Re: DHS D40+ three star balls, good news

Come to think of it.. how can you tell the backspin is dying quicker??

Iskandar

Author:  Lorre [ 08 Aug 2017, 07:35 ]
Post subject:  Re: DHS D40+ three star balls, good news

iskandar taib wrote:
Come to think of it.. how can you tell the backspin is dying quicker??

Iskandar


Because the sparring partner, doing the same drill as with the ball you're comparing the D40+ with, has an easier time to loop. This is done by doing the drill on the same night, one with the D40+, the other with the ball you're comparing that ball to.

Author:  Baal [ 08 Aug 2017, 09:06 ]
Post subject:  Re: DHS D40+ three star balls, good news

d1244 wrote:
DHS D40+ is made from the new material and the ball is much harder than other ones. Moreover, D40+ is much noticeably heavier. I would guess it is a matter of weight and surface texture combined making it jump further forward by topspin.


Actually, at the moment only the Nittaku Premium are lighter, and tney are also ABS. Latest D40 anyway, are around 2.73. I don't think survace textures are very diffefent except for G40, as was me tioned.

Author:  iskandar taib [ 08 Aug 2017, 18:35 ]
Post subject:  Re: DHS D40+ three star balls, good news

Lorre wrote:
iskandar taib wrote:
Come to think of it.. how can you tell the backspin is dying quicker??

Iskandar


Because the sparring partner, doing the same drill as with the ball you're comparing the D40+ with, has an easier time to loop. This is done by doing the drill on the same night, one with the D40+, the other with the ball you're comparing that ball to.


That might not be the spin dying off, though, it might be 1) not being able to generate as much backspin to begin with, or 2) the ball not interacting as much with the rubber. I think someone needs to bring in the marked balls and the high speed cameras before we can tell exactly what's going on. However, the effect is another matter - that can be obvious.

Iskandar

Author:  Lorre [ 08 Aug 2017, 23:15 ]
Post subject:  Re: DHS D40+ three star balls, good news

iskandar taib wrote:
That might not be the spin dying off, though, it might be 1) not being able to generate as much backspin to begin with, or 2) the ball not interacting as much with the rubber. I think someone needs to bring in the marked balls and the high speed cameras before we can tell exactly what's going on. However, the effect is another matter - that can be obvious.

Iskandar


True, but I had the impression that my opponent could deliver more and more spin by attacking - contradicting (1) & (2) - while the backspin I could return was capped. So I don't attribute it to (1) or (2), but spin lost in ball flight to and from my LP rubber.

Author:  iskandar taib [ 09 Aug 2017, 03:00 ]
Post subject:  Re: DHS D40+ three star balls, good news

Yeah, we need the high speed cameras... :lol: This is weird.. backspin behaves one way, topspin the opposite.

Iskandar

Author:  Baal [ 09 Aug 2017, 12:38 ]
Post subject:  Re: DHS D40+ three star balls, good news

iskandar taib wrote:
Yeah, we need the high speed cameras... :lol: This is weird.. backspin behaves one way, topspin the opposite.

Iskandar


Yes. And a robot to deliver balls consistently.

Author:  Lorre [ 09 Aug 2017, 19:32 ]
Post subject:  Re: DHS D40+ three star balls, good news

Iskandar, Baal, NextLevel and probably some others...

Well, make it happen. Deliver us scientific results! ;) It can't be that hard to set something up. We'd be glad with RPM in a controlled environment.

Author:  kaesees [ 09 Aug 2017, 22:28 ]
Post subject:  Re: DHS D40+ three star balls, good news

I think PathfinderPro used to do these sort of investigative videos somewhat frequently. Maybe he/his club still have the setup?

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