Trad Gang
Main Boards => PowWow => Topic started by: Doug Campbell on March 04, 2006, 02:59:00 PM
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I've already taken it down to my office so can't tell ya the author but it was very informitive. Answers many questions that have been argued for some time. Great read :thumbsup:
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Yep, that was a great article. really dispelled some myths, didn't it? Anyone who hasn'r read it needs to. Lots of great info.
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When it gets here I will be sure to read it.Waiting!!!!!!!!!!!!
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Not sure that I believe the results or trust the author and his testing methods. For one thing, it seems intuitive that "creep" would be the original stretch of a new string and "stretch" would be the stretch each shot.
Also, the author's dismissal of 5 fps being significant bugs me.
Sounded like he used mechanical release but not a shooting machine. Unless he used at least a clicker or other draw check, it would be very hard to duplicate draw length.
Would have also like to see a broader range of bow types and arrow weights.
In general, it did not stike me as valid scietific method. Still, some food for thought.
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Hmm... definately food for thought. Maybe now that this "study" has been done some "scientific" person will come along and try to improve on it. I'd sure like to see it.
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I've got to check this article out ...
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A real eye opener. Generally the fast flight materials yield a 5fps faster arrow, and string weight didn't seem to affect speed. Hope others will replicate the study. There's lots of confusion in this area and this is an excellent first step.
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I haven't read it yet, but I will go out on a limb and say that if string weight didn't effect the results, someone wasn't doing their testing correctly.
You cannot change moving mass without affecting speed.
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Jeff,
Exactly! How can a bow with a fixed amount of stored energy shoot two strings of unequal weight with the same speed. That goes for the number of strands causing the weight change as well as adding silencers, brush buttons, etc.?
My testing has not been anywhere near "scientific", but these are not the results I've found at all.
Joe
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Hope I can find it--looked today, but it wasn't on the rack--how long has this issue been out?
One thing I've noticed is there are no absolutes, string weight can affect speed (how much will vary), and unless the author used a shooting machine and a LOT of different bow styles and weights, his results are very questionable.
Chad
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LBR,
This article is in the latest issue. I just got it a few days ago.
I am not a scientist, but I just didn't buy all his "scientific" results. Admittedly, I read it in a hurry and probably should go over it again, but I just don't believe that there is no significant advantage of the fast flight strings to dacron.
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Hmmm, I thought I was the only one questioning the results...
Lets give the guy innocent until proven guilty, he did say he shot 500 times! But...
I just can't beleive the results, knowing how much I can change tune/bare shaft with silencers and string material at home. Just sliding a silencer up the string can change a shaft from stiff to weak.
Some of these chrographs are not to accurate you know, and how did he control draw length.
Does a string material manufacturer have data to coincide? Someone has too? Why only 452, why not try 8125 or TS1?
a 100+ grain difference in string weight did not change FPS? 6 strands no faster than 12 strands?
What about the loss of speed from B50 slaping your wrist? When a fast string won't touch it.
Fast strings gain more like 10-12 FPS right?
Somethings not right
Can someone back this up.
We need a string manufacturer to weight in on this
Tedd
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I haven't read it either so don't know what they said or how the testing was done. I will say we've done a LOT of testing in this area and any differences seen are 99% mass related and the other 1% is drag due to string diameter. How much string mass effects arrow velocity depends on where that mass is located. 10 grains in the serving area is the same as adding 10 grains to the arrow, 10 grains in the loops is like adding about 3 grains to the arrow.
If a person used under built Dacron and over built modern strings, yes the results could be minimal. If compared strength to strength, IE: the same pounds breaking strength between strings, the results would be MUCH greater then 5 fps.
Energy is divided up between limb mass, string mass, and arrow mass. Increase the mass of any one and less energy goes to the other two and vice versa.
5 fps at the same gr/lb??? That's only the same as short drawing or over drawing more then 1". Anyone that's been shooting more then a week can "see" how significant that is when we do it in the field. It'll be interesting to see who the author is, bet there's an underlying agenda some where. There was an article written many years ago called "Anatomy of a string", they came to similar 5-6fps conclusion but "spun" it as being insignificant looking at fps as a %. Looking at fps is like looking at RPM in an engine, it doesn't relate to horsepower in itself. This one was written by a bowyer who didn't like folks using non-stretch strings on his bows for failure reasons....O.L.
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Amen O.L. What the heck would we do without you!?
I'll read it again tonight, maybe I'm missing something?
Tedd
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Shaun, I was really confused over his stretch/creep thing too. Did he have that backwards? I was probably half sleep when I read it.
Tedd
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Maybe his Chrono is like mine and he just doesn't know it yet. My Chrono is a pc of crap. I gives false readings all the time.
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Let me throw a thought out here, since we are talking about strings and performance.
After thinking through the mechanics of an arrow coming out of the bow, I have come to the conclusion that the "stretch" aspect of string material is a red herring. Unless the string is stretching DURING THE DRAW and not recovering it's original shape until after the arrow is gone, stretch cannot possibly affect the performance of an arrow.
Think about it. When is string stretch most likely to occur? When the bow slams home to brace height, right? Folks, THE ARROW IS ALREADY GONE before that stretch ever occurs. Such stretch can't have any effect on how much energy the arrow left the bow with. You might get more handshock, but the arrow couldn't care less.
I am with O.L. The difference between string material is strictly weight versus strength. Stetch or lack of it don't mean a thing.
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Or...if a string stretches when slaming home at brace height is that a waste of energy that could have gone into the arrow?
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Jeff,
I'm not sure, but I believe the arrow nock will stay in contact with the string until the strings stops all forward movement.
Joe
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Joe, I have to agree with ya....
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I'm just glad I'm not the only one who hasn't received my TBM.
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Joe/ Guru
Yes it would be in contact with the nock when during full forward travel...but after brace height the string is just along for the ride. the bow can't be "pushing" on a flexible string.
Right??
Tedd
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Joe,
If that were the case, I doubt we would ever get an arrow off the string cleanly. One of the big culprits in bad tuning is nocks that are too tight. They hold on to the string too long and cause all kinds of havoc.
The arrow should leave the string as soon as it's own velocity exceeds that of the string.
Tedd,
Can't be. That energy already had the opportunity to transfer to the arrow. Whether the string stretches as a result of energy left or not is irrelevant.
Put another way, whether you stretch the string or pound the nocks with that energy, it still ain"t going into the arrow.
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Dacron does stretch during the draw, at least more than Fast Flight. Why? Because if I make a Dacron string and a Fast Flight string for a bow, the Dacron string will have a lower draw weight by a couple of pounds (same brace height, same bow). I also noticed the same when making a linen string. I believe (I haven't done any controlled testing) that it's the energy wasted in the Dacron string stretching that makes it slower than Fast Flight.
Jason
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Should be easy enough to prove or disprove, Jason.
Build two strings that weigh exactly the same, one of dacron and one of fast flight. I'm betting they shoot within one FPS of each other.
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Jeff, We've done just that and you are correct. Easy thing to do. One of the things that "bite" folks doing testing of any kind, is keeping all the variables constant except the one you are trying to test. When someone says "that can't matter that much", they are in trouble right there. Bet cha dollars to donuts the testers in this test did not take into account nock fit on the string. At 60+# bows at 28", we've seen 4-5 fps between a tight nock and same arrow with the nock loosened up. I've seen 10 fps on bows in the 40# range due to tight nocks. You'd think the FF would looser but not if the string maker used a thicker serving like many do. Would be interesting to find out. Seen a thick quill snagging a rug rest lose 4-5 fps, so many little details that can cause misleading conclusions....O.L.
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when i began to first test the speed of my trad bows back in 2000 i had a martin dreamcatcher with the stock dacron string. it was funny, i could run it with a clicker and as the serving wore down to a proper nock fit the bow just kept getting faster. almost 5 fps over a couple week period. since that time, i've been a stickler for nock fit being correct. that habu i've got had the most dreadful nock fit on that cable of a string to the point the nocks would pull off my arrows. finally broke down and ordered the same string that came on the cx from rod. gained over 10 fps right there. wasnt' just the string material, as the nock fit was a major gain just due to the proper serving.
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Anyone else read this thing? Bear in mind I'm just a simple country boy but I went back and reread this thing. Other than not using a shooting machine or some way to insure exact draw length he seemed to do a pretty thourough test.
OL, you guys published any of your findings?
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Wow! I do a search for "brush buttons"... and I get this!
Fascinating stuff!
ttt