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Ever hear of this?

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Re: Ever hear of this?

Postby Bender » Tue Jul 17, 2012 2:50 pm

Oops, yeah, center serving.
Anyway I'm just sayin' that despite Beck's "challenge" you CAN get a faster arrow with a skinny string. The gain is small but definitely there, measurable, and larger than margin of error. And given the right guy shooting it, it MAY even be a shootable difference. However, obviously in order to make it so you need to be free to construct the string in such a fashion that you can shed significant mass. Beck's constraints made that impossible. (personally I couldn't shoot the difference as the skinniness "hung" my release. Couldn't get off the string clean. So I'm not pushin skinny strings, just that the speed gain is real should one wish to pursue it.)

The tests I did were on a specific bow. (I can't possibly test all bows due to time and resources and $. Like you mentioned there's no money in it to get a sponsor) I shed the mass by basically building an endless loop the same as I build all my endless. However I made the end loop serving short as possible, the center serving short as possible, dropped 4 strands, from 10 to 6, kept the center serving single wrapped, went to a smaller arrow nock, and used dental floss wrapped ONLY at the nock point to achieve nock fit. And like I said it was a 1.7% gain. Which with this particular bow was just at 2 fps. Not a real game changer.

Here's something to consider, and please remember I'm only screwin' with ya, pushing a semantic argument. You mention comparing apples to apples. Considering that most "standard" strings as supplied by a string maker are single wrapped center servings, when you make a double wrapped string haven't you basically made an "orange"? Isn't the double wrap outside the norm and so as such is the oddball and it negates the comparison rather than supporting the comparison?

I think that actually what it comes down to is that skinny strings are for folks who can make their own strings to fool around with. A commercial builder such as yourself would probably be making a mistake to start promoting and selling skinny strings. Sure performance is important to you, but there has to be a trade in that the professional also needs to make a nearly bullet proof product. Its like durability really IS an aspect of performance.
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Re: Ever hear of this?

Postby LBR » Tue Jul 17, 2012 3:10 pm

Beck's constraints made that impossible.


That's what I'm trying to get the details on--so far, no luck. I can't come up with anything I couldn't negate one way or another--if I can figure it out, surely others could--especially those that claim to get such great results from tiny strings.

However I made the end loop serving short as possible, the center serving short as possible, dropped 4 strands, from 10 to 6, kept the center serving single wrapped, went to a smaller arrow nock, and used dental floss wrapped ONLY at the nock point to achieve nock fit. And like I said it was a 1.7% gain. Which with this particular bow was just at 2 fps. Not a real game changer.


And that is typical. Not only did you drop strands, you shortened the center serving (the main difference IMO) plus used a smaller center serving...and only got a tiny increase. That goes along with everything I know, and the results from people I know and trust. You aren't claiming 10-15 fps, or a change that would require major re-tuning, heavier spined arrow shafts, etc. etc. etc.

Makes sense to me you would lose a a tad in draw weight with a string that has some give to it versus one that doesn't and that alone would make a slight difference in performance.


Hank, you have tinkered with Dynaflight '97 haven't you? Do you honestly think 14 strands has any amount of elasticity, especially under less than 70# of tension? How about over an inch of stretch under less than 70# of draw? It would take over an inch to vary 4# in draw weight. What do you think that would equate to with dacron?
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Re: Ever hear of this?

Postby LBR » Tue Jul 17, 2012 3:17 pm

Considering that most "standard" strings as supplied by a string maker are single wrapped center servings, when you make a double wrapped string haven't you basically made an "orange"? Isn't the double wrap outside the norm and so as such is the oddball and it negates the comparison rather than supporting the comparison?


I don't think so. I've made some fairly "skinny" strings by request, and like I noted...when you have to double-serve, you wind up using a small diameter serving so the end result really isn't much bigger than a single wrap of a larger size. That would be the biggest difference, but not a game changer.

A commercial builder such as yourself would probably be making a mistake to start promoting and selling skinny strings. Sure performance is important to you, but there has to be a trade in that the professional also needs to make a nearly bullet proof product. Its like durability really IS an aspect of performance.


Well, yes and no. Durability is a big concern of mine, and a big negative to me with the low strand count strings. However, I would offer them (with warning) if I thought there was any real benefit to them. 2 fps???? My release varies by more than that, as does dang near everyone else's.

All the smoke and mirrors crap is a big peeve with me. The top-secret super-duper double-tight twist; the goofy names people come up with for strings; the outrageous claims...what happened to selling a product on it's actual merits?

Like I said, guess I'm a lousy businessman--I can't handle all the bs.
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Re: Ever hear of this?

Postby Bender » Tue Jul 17, 2012 6:53 pm

Bowstring Tension IV.JPG
Bowstring Tension IV.JPG (24.07 KiB) Viewed 2117 times


OK after figuring out to convert a file to jpg then the site will accept it, the above is a graph of string tension during draw and then release. The black line is string tension during draw, the green line is string tension after release.

It seems weird but as counter intuitive as it is here is the best I can explain it. We tend to forget that when dealing with force vectors, vectors have directionality, and their magnitude is affected by angles. At brace the force is a straight line, trying to rip the string in half. But as we draw, direction and angle change, and some of that force is transferred back to the limb tip, tending to try and rip the bow in half. Energy is neither created nor destroyed, we just move it around.
So given this unique phenomena, it becomes ever more apparent that Barbee's test IS flawed. The only way to stretch a string more is to apply MORE tension. Yet tension actually falls off. He is attempting to measure something outside the level of forces we're dealing with in a bow, and trying to do it with equipment that just can't handle the task
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Re: Ever hear of this?

Postby Hank » Tue Jul 17, 2012 7:36 pm

I think Rick used to shoot really heavy bows, which might slant things as well.

Who in the hell uses a 14 strand D 97 rope?
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Re: Ever hear of this?

Postby LBR » Tue Jul 17, 2012 9:13 pm

Thanks Bender--I'm starting to get my head wrapped around it.

Hank, the 14 strand is what he tested with. It's a stock BW string--I imagine to keep from having to pad the loops.

14 strands of Dynaflight '97 isn't that big--maybe the size of 10 strands of 450+. It is overbuilt for most bows, but when I shot it on my 66# longbow I averaged 187 fps. That's shooting with a glove, silencers on the string, arrows that weighed 9.5 gpp, and a pretty lousy release. I've dropped to 12 strands now. :mrgreen:

I don't think a heavy bow would cause a difference, because the most difference I've seen and heard of using a lighter string is with lighter draw weights. He heavier you go, the less it seems to have any affect--and as Bender noted, it didn't have much to begin with.

Just doing the math in my head, if Rick's test was accurate, then if he switched to a dacron string he should loose 20 or more pounds of draw weight, since dacron is so much more elastic than Dynaflight. We're getting into vapor's 10# worth of performance per inch of draw territory with that-makes as much sense (none).
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