spin potential of natural gut ?

[Smasher08]

Also, I think we need to find some more Simon pics. His strings look perfectly straight in that picture just pushed backwards.

Zoom in on it. Look to the top of the ball, then go one main below that. It's definitely deflected, you can see the shallow parabola shape. Simon uses a dense pattern stringbed so you don't get deflections as extreme as in an open one, perhaps due to the fact that the ball's energy is borne across a greater number of strings.

And if you're still skeptical, go back to the Federer pic and zoom in on it too. Look to the top of the ball, and then skip one main below it. Same deflection, albeit much more pronounced. And unlike Simon's mains, Fed's got at least two deflecting.

 

[Chyeaah]

Has to be before, otherwise there wouldn't be any spin imparted.

This can be argued.

No.1 It would change with different strings.
No.2 If the ball left before the string snapped back there will still be spin.

 

[Chyeaah]

I suggest get some Nadal point of contact pictures it will be evident on his if this hypothesis is true.

Currently this is the only one that I can find but it isn't very clear but the strings do not seem to be moving. The ball is full deformed.

Does Federer string his crosses very different from mains? As if you have tighter crosses than mains then the mains might move easier. and vice versa.

 

[Smasher08]

No.2 If the ball left before the string snapped back there will still be spin.

Not top spin. The ball would, presumably, retain the same directional spin it had pre-contact, albeit slowed down.

 

[Smasher08]

I suggest get some Nadal point of contact pictures it will be evident on his if this hypothesis is true.

Voila Tsonga, playing (I believe) full-bed poly.

 

[Smasher08]

This can be argued.

No.1 It would change with different strings.
No.2 If the ball left before the string snapped back there will still be spin.

1. It *does* change with different strings . . . in that strings which deflect more and snap back more generate more spin.

2. The balls that these pros are hitting are rotating 30-40x per second. That wouldn't be possible unless the snap back occurred while the ball was still in contact with the stringbed.

Second of all, remember tht the stringbed deflects and snaps back longitudinally as well. If the snap back was as slow as you're suggesting, the dwell time would be much, much, much longer than you know it to be.

 

[Smasher08]

I suggest get some Nadal point of contact pictures it will be evident on his if this hypothesis is true.

Does Federer string his crosses very different from mains? As if you have tighter crosses than mains then the mains might move easier. and vice versa.

Unfortunately pros using black strings only make the job tougher:

Federer strings his crosses lower than his mains, 2 or 3 lbs I believe.

Looser crosses than the mains will facilitate mains movement, presumably much more than the opposite. My guess would be that looser crosses offer less resistance to mains deflection.

 

[Deschain]

Below is a good article/video regarding spin, the video shows the snap back of a synthetic gut string vs the same string coated in a lubricant (WD40 I believe).

http://www.wired.com/wiredscience/2...ven-better-than-you-think-a-story-about-spin/

 

[Smasher08]

Thanks for sharing, Deschain. Welcome to TT.

 

[ChicagoJack]

Don't know why Smasher08 is taking so much heat for supplying information on an issue that is old news. The fact that (slippery) string snaps back into place, and imparts additional spin on the ball on exiting the string bed was validated with extensive lab testing several years ago. There is video all over the place including multiple links here at the TW university. It was a very big discovery. Before this time, (following very controlled testing done at the University of Sheffeild) .. the dudes in the white lab coats were saying that string makes NO difference at all, with regards to spin production. None, zero, nada. The entire racquet physics community (excepting our very own travelerAJM) has had to completely reverse its position and re-write all the books. Slippery string does impart more spin.

It's old news.

-Jack

Quote : "Does lateral string movement during impact contribute to spin? Several experiments on Tennis Warehouse University (TWU) have investigated this question (Spin and String Material, Spin and String Movement, and Spin and String Pattern, Spin and Sliding Friction, and Spin and Static Friction). The assumption of these experiments was that if lateral string movement and snap-back (torquing and spinning the ball) do enhance spin, then anything that facilitates lateral movement will also tend to increase spin. The results of these experiments added support to the lateral snap-back theory. But all but one of these experiments was performed at low impact speeds. The experiment detailed here was performed at impacts around 52 mph. Impacts were filmed to observe ball-string interaction, snap-back in action (hopefully), and/or events that suggest correlations between string movement and spin."
-- TW University

Links Below:

http://twu.tennis-warehouse.com/learning_center/stringmovement.php
http://twu.tennis-warehouse.com/learning_center/stringmovementPart2.php
http://twu.tennis-warehouse.com/learning_center/spinandstiffness.php


Quote: " Copoly strings help generate so much spin that today’s players—dubbed the “new-string generation” by Federer— can hit once-inconceivable drives, angled winners, and passing shots. But despite the widespread belief of players that copoly strings have changed the game, scientists until recently could find no evidence that a string’s material, thickness, tension, or texture made a real difference in spin generation.

Enter the Japanese engineer Yoshihiko Kawazoe. In 2004, he decided to test a string lubricant that its inventor, Kenji Okimoto, thought would “revive” old, worn strings. Kawazoe realized that, despite much research, scientists had only a shadowy idea of what happens during the 4 or 5 milli­seconds when the ball is on the strings, simply because they couldn’t see it. But with an ultra-high-speed, 10,000-frame-per-second camera, Kawazoe solved the mystery of strings and spin.

In capturing 40 to 50 frames of each ball-string impact, he saw that lubricated strings slid with the ball and snapped back as it left. As they snapped back into line, they transferred more energy to the ball in the tangential (parallel to the racket face) direction and gave it more spin—which was easily calculated from the super-slow-motion rotation of the ball as it left the strings. In technical studies published in 2006 and 2007, International Tennis Federation researchers reported that the same movement that Kawazoe observed with lubricated strings occurs with copoly as well.

Copoly strings—slippery and stiff—generate more spin not because of more friction, but because of less. “The old argument was that the better the grip between the strings and the ball, the more spin you would get. But that’s not true,” said Rod Cross, an Australian physicist and co-author of Technical Tennis.

Last April, Cross and his co-author, Crawford Lindsey, published their study showing that copoly strings generate 20 percent more spin than nylon strings, and 11 percent more than natural gut. Such differences help explain how a contemporary powerhouse like Rafael Nadal can hit with twice as much spin as Andre Agassi did.

Looking back, Lindsey and Kawazoe told me they are befuddled by how long people took to realize that polyester strings generated extra spin through sideways sliding and snapback. They should have known this, because 30 years ago, a radical innovation—“spaghetti strings”—used the same mechanism to generate more spin than even the best copolys.

“In spaghetti strings, the [horizontal and vertical] strings weren’t woven,” said Cross. “And because they weren’t woven, there was lots of freedom of movement within the string plane, and that produced almost a factor-of-two increase in the amount of spin. And that’s why the ITF banned them.”

-- The Atlantic Magazine,
The New Physics of Tennis,
Unlocking the mysteries of Rafael Nadal’s killer topspin,
By JOSHUA M. SPECKMAN
http://www.theatlantic.com/magazine/archive/2011/01/the-new-physics-of-tennis/8339/

 

[ultradr]

wow, let's ban polyester.

thanks everybody. i finally understand why poly generates more spin.

spagetti >> poly > natural gut > nylon

 

[Say Chi Sin Lo]

Don't know why Smasher08 is taking so much heat for supplying information on an issue that is old news. The fact that (slippery) string snaps back into place, and imparts additional spin on the ball on exiting the string bed was validated with extensive lab testing several years ago. There is video all over the place including multiple links here at the TW university. It was a very big discovery. Before this time, (following very controlled testing done at the University of Sheffeild) .. the dudes in the white lab coats were saying that string makes NO difference at all, with regards to spin production. None, zero, nada. The entire racquet physics community (excepting our very own travelerAJM) has had to completely reverse its position and re-write all the books. Slippery string does impart more spin.

It's old news.

-Jack

It's TT, idiots argue just for the sake of arguing. When the argument fails or in doubt, turn up the heat.

 

[Chyeaah]

It's TT, idiots argue just for the sake of arguing. When the argument fails or in doubt, turn up the heat.

No. I'm arguing that the majority of the spin is not by the snapback of the strings.

My belief if that the string grabbing onto the ball + the racquet headspeed gives the majority of the spin, then the snapback comes in to add extra.

 

[ChicagoJack]

It's TT, idiots argue just for the sake of arguing. When the argument fails or in doubt, turn up the heat.

I don't think anybody here is an idiot. I have requested string advice from Mike, Ramon, U&C, and Smasher, and though there seems to be varying levels of agreement none of those fine folks have done me wrong. I just think everybody (myself included) filters, and compares information through what it is they already know.

I think I understand what some very experienced string folks here are pointing to. It's difficult to figure out how a gummy, sticky, string like Head Rip Control, a string that clearly needs constant realignment in between points, (even needs constant realignment strung at 62 lbs, in a 95 sq in frame) can be so spin friendly. I played a full bed of RC for like 3-4 years straight. I kept demoing on the side with various poly setups and was seeing very little dif in spin production. I don't care how many links I posted on the whole slippery string snap back thing, that particular string is just inexplicably spinny. Sometimes you just know what you know, no matter what anybody says, and even when it flies in the face of all the lab data and theories.

Peace my brothers and sisters.

-Jack

 

[Fugazi]

This past week I tried a controlled experiment with:

- gut/poly

- full poly

- full gut

in the BLX Pro Staff 6.1 95.

I also compared the results to:

- full gut in a BLX Surge

- full multi in a Pro Open

- full multi in a EXO Tour Team 100

- Gut/Poly in the Speed 300

- fully poly in the Speed 300.

Some of the frames just happened to have these strings already in them and I was "lucky" enough to have broken strings in two of the frames.

RANK OF ACCESS TO SPIN
1. Gut/Poly Hybrid (brain dead easy)
2. Full Poly (Black Widow/Focus Hex hybrid...easy but gut/poly was a lot easier)
3. Full Multi (pretty good)
4. Full Gut (distant 4th place, you really need to nail it.)

In all cases I had the easiest time generating extreme spin with the gut/poly hybrids. They even out performed the full poly SBs. This is consistent with my experience over the last 18 months experimenting with different stringbeds.

In one case I used the TWU friction data to come up with what should be one of the best performing full poly stringbeds: Black Widow 16 mains and Focus Hex crosses. Black Widow has one of the highest ball friction values tested by TWU and both BW and Focus Hex have very low string friction values (Hex has one of the lowest). In theory the super high ball friction of the BW should have grabbed the ball hard and the low friction between the mains and crosses should have caused the strings to slide easily.

Well, the mains and crosses do slide easily with BW/Hex. The spin was better than full multi and full gut. But this full poly setup still trailed far behind gut / poly.

The worst performer was full gut. I really had to concentrate to generate high top spin. Full-multi (NXT 17) was pretty good. Not as good as full poly or gut/poly but still much better than full gut.

The best performing stringbed I've tried with respect to spin generation is Wilson Natural 16 with CoFocus crosses. Wilson Natural with Focus Hex crosses also generates insane amounts of spin but with a little more control, especially in larger heads with more open patterns. The CoFocus crosses work better in denser SBs imo.

Interesting. Can anyone evaluate where a poly/gut (or poly/multi or poly/syn gut) would stand in that list?

 

[Fugazi]

Polys aren't of uniform smoothness. CoF is somewhat of an anomaly in that it's one of if not THE smoothest non-textured copoly out there. I suspect it has something to do with both its surface finishing and its elasticity.

Try another MSV string with the same chemical composition (i.e. Heptatwist or Focus Hex) for a better comparison.

I think your use of the word "rough" is a bit of a misnomer here. Texturing may make a string feel rough to the touch, but that's due to the density of touch receptors in our fingers. On a microscopic level, the surface of these polys is still relatively smooth. It's the synguts and certain multis that are comparatively rough.

Who knows, maybe Federer uses Luxilon rough in the crosses precisely because this gives him just the right amount of spin; too much spin would probably take away some of the penetration in his shots.

 

[Fugazi]

Is it me or a rough poly/smooth poly hybrid setup will create more spin than any other poly combination? (smooth/smooth, smooth/rough, rough/rough). The logic is this: rough poly mains will grip the ball well (better than smooth poly), and yet slide and snap back relatively easily on the smooth crosses. I guess it's also possible that a smooth/smooth combination could be superior (less grip on the ball per se with the mains, but maximum sliding-and-snapping-back effect). Anyone?

 

[Fugazi]

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