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Author Topic: fast flight on vintage bows  (Read 2067 times)

Offline artifaker1

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Re: fast flight on vintage bows
« Reply #20 on: November 04, 2009, 03:15:00 PM »
Actually, after further thought, with a moderately skinny string, we are probably even under 10% breaking strength.
10 strand 8125, 100lbs per strand, around 1000lbs, with a 60lb bow is less that 10 percent.
We might want to design a skinny string that would be closer to 20 or 30% to introduce some stretch. Just like Bjorn is using.
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Offline artifaker1

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Re: fast flight on vintage bows
« Reply #21 on: November 05, 2009, 12:55:00 AM »
Well I found more some data on Dacron and some other fibers. For the amount of stretch that is. A single strand of Dacron has about 43lb breaking strength by one source. The stretch rates are at 30% of breaking strength.

Nylon             14%
spectra xls 800   1.25%
wire rope 7x19    1.25%
spectra xls 900    .95%
braided dacron    5%
dacron stayset x  3.25%
sk-75              .96%

These values are for rope but are the right fibers basically. The other thing to consider about dacron is we use it a lot closer to the breaking point than sk75. So the stretch rate will even be higher. I.E. rubber bands compared to sk75 at about 5% of the breaking point, if that.
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Offline Hud

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Re: fast flight on vintage bows
« Reply #22 on: November 05, 2009, 03:05:00 AM »
I have had several bowyers tell me that FF and newer should not be used on their older bows.  That is why they switched to multiple tip overlays, or wedges depending on the design and type of bows. They also say it should not be use with horn tip overlays, either.

However, some are bound to try it, just to see if they can, and then say they did. Then, there is the man that hires himself as his own bowyer and finds out later that he has a fool for a client.

Has anyone seen or tested a single strand of B-50, D97, FF etc, by taking a 5 ft. long strand and hang a 12.9 lb weight (43# x .30) on an "S" hook. Record the exact length of your string, and check later to see if there was any stretch?

If you try it, remove the weight and see if the string recovers? You might get a better idea how the different materials are going to perform. if your getting some stretch, then compare it to the older B-50.
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Offline hunterken

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Re: fast flight on vintage bows
« Reply #23 on: December 21, 2009, 10:17:00 PM »
I've shot a Bear hunter takedown recurve with fast flight for 10 years, my brother probably longer with absolutely no issues.

Offline avcase

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Re: fast flight on vintage bows
« Reply #24 on: December 27, 2009, 03:21:00 PM »
I've been using a very thin 6-strand TS+ string with padded loops on a very old Groves bow for quite awhile now (1000's of shots)with no problem.  There is a very noticeable performance gain with no down side that I am aware of.  I use a double nock point made up of polyester sewing thread saturated with glue for a perfect nock fit.  I haven't had issues using the modern super string materials with all-wood laminated bows, wood self bows, or English style long bows with horn tips.  The modern string material delivers more energy to the arrow so less is left in the limbs after the arrow leaves.  I can see where a high strand count fast-flite type string may be harder on a bow during a dry-fire.  I agree with the posts above that recommend to not using more strands than is necessary to help solve that issue.

I don't know what to say about experiences with delaminations.  The old linen strings were similar or even less elastic than the new fast-flite strings and it worked fine on bows for thousands of years.  My opinion is that some bow designers became complacent and lost a lot of knowledge about strings and bow design when B50 came out along with mass produced glass bows.

A note of caution about strings.  I have tested several different string materials in the last couple of years and have found that the breaking strength of many commercial bow strings is about half what is often published.  My TS+ has a breaking strength of about 50-60 lb.  My B50 tested 20-25 lb.
-Alan

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Re: fast flight on vintage bows
« Reply #25 on: December 27, 2009, 04:24:00 PM »
Interesting,please keep posting more infos when they will be available.
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Offline Hud

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Re: fast flight on vintage bows
« Reply #26 on: December 27, 2009, 06:22:00 PM »
Alan, did you determine how much stretch you obtained in your testing?
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Offline avcase

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Re: fast flight on vintage bows
« Reply #27 on: December 27, 2009, 09:37:00 PM »
Hud,
I measured the stiffness of the bow string materials(% stretch per lb load) but I did not measure string creep (gradual permanent stretching of the string when under load).  I used these measurements in a program I put together for designing and simulating stick bows performance.  I can dig this up.

The way I tested the string breaking strength was to hang a barrel from a 6' length of string and I filled the barrel with water until the string broke.  Then I weighed the barrel + water afterward.  I found that my spring scale and digital scale were not reliable enough and the shock of the string breaking would result in a much higher reading compared to what I got with the bucket+water+weigh method.  Pretty primitive, but it worked well.  Stiffness was measured with a very long length of string (like 30') and measuring the stretch Vs. load, kind of like measuring a force-draw curve on a bow.
-Alan

Offline artifaker1

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Re: fast flight on vintage bows
« Reply #28 on: December 27, 2009, 09:50:00 PM »
I just started using a 6 strand 8125 padded to 20 strands on a Bear Grayling takedown with no. 3- 39lb limbs and rose future wood overlays. I have shot it quite a bit and kept a very close eye on the string nocs to see if it starts to cut them. So far so good. The bow "shoots better" is an understatement. The limbs stabilized at an 8" brace height, where before I had to take it up to 9+ to get them to stop throbbing on an A riser. It is shooting the same arrow as a 36lb Black widow or very nearly. It shot a much lighter spine arrow before.
But I have second thoughts about going down to six strands, I think that ten strands might be alright. And it keeps other people shooting around you from freaking out, . More later.
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Offline Hud

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Re: fast flight on vintage bows
« Reply #29 on: December 28, 2009, 03:22:00 PM »
Alan,
I wondered about the spring scale, but you have answered that question. The dead weight method sounds reliable. I am not surprised the mfgr ratings are higher.  

In an old interview and published article,Fred Bear said he preferred a heavier string. He thought it was quieter, and offered a margin of safety, in case a strand was cut. I believe he used 18-20 strands on his 65# Kodiak and TD's. I confident it was B-50 and then maybe D97 (pre 1988).

I have no problem with light strings, but tend to favor heavier strand.  When I was shooting, a fair amount of 3D, I saw a few bow break, but it was not known whether it was a bow or string problem.

When I was in high school, I had a string (B50) cut thru the tip overlays on an Bear Kodiak, causing the backing to separate from the laminations with the string peeling thru about 6-9 inches when at full draw. Bear used paper overlays for the tips on that bow and at the time I was buying strings for the dealer. Barry
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Offline artifaker1

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Re: fast flight on vintage bows
« Reply #30 on: December 28, 2009, 09:00:00 PM »
Ya, Barry it is good to here from you again.
I wouldn't use B-50 for a skinny string. I have argued that the performance is better with the heavier string with Dacron and I'm going to say that it is due to the moderate stretch rate of Dacron.
With 8125(SK-75 92% SK-65 8%) you have a completely different animal. Or with 452X being part Kevlar or Aremid. These materials are so much stronger, with virtually no stretch. My 6 strand 8125 is 720lb. That is the same as a 14 strand B-50.
I could tow my truck with an 18 strand D-97, no wonder they tore up tips on older bows.
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Offline Hud

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Re: fast flight on vintage bows
« Reply #31 on: December 28, 2009, 10:37:00 PM »
Larry,

My experience with a Bear Kodiak in 1957 to 59 was with a factory or dealer string. Probably B50, maybe B43. I doubt it was 18 strand, because the bow was around 55#. Even at 14-16 strands, it would be heavy by todays standards, or what your using, but it was standard back then. The bow was new, and not 50 yrs old. I personally, feel the shock is less than it would be from a lighter string because the limbs would recover faster with a lighter string, producing the extra speed your looking for. Consequently, I would not be tempted to use a lighter B50, or newer non-stretch string on my 1950 Vintage bows anytime soon. I would give it a try on a newer style bow under the right conditions. To me the extra speed, is not worth the risk.

As Allen found out, the strings material he tested, broke at about 1/2 the published rates. That is pretty significant in my estimation. It would be interesting to see what the 8125 would hold up to under the same test.

Obviously, your experience has been good with the Bear TD with Futurewood tip overlays. I think you'd agree, they are stronger than the early models with paper overlays. Futurewood was an impregnated wood that was much stronger after the process.I am interested in learning more as it relates to Vintage bows including yours. Thanks for info.
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Offline artifaker1

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Re: fast flight on vintage bows
« Reply #32 on: December 29, 2009, 09:32:00 PM »
Ya Barry, I would prefer that the tips were one of the micarta sets. If the future wood tips hold up then you know there is no problem, cause the others are micarta anyway, on the takedowns. A thin layer of micarta is all some bowyers use on there fast flight limbs.
As to the testing, well it is highly probable that he might not be testing the fibers right. And it may be intentional.
If BCY can come up with the engineering for the fibers I just see no reason why they would manipulate test readings. Or why they would not have a true test of the fiber. The rope manufactures' demand accurate testing on all fibers including SK-75. This info is needed in the act of rigging. So BCY is not the only people testing SK-75. It's strength is not unknown. The latest that I seen on 8125 is 120lb.
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Offline Hud

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Re: fast flight on vintage bows
« Reply #33 on: December 30, 2009, 12:42:00 PM »
Hey Larry,
Your probably right about BCY, but B50 and D97, Fastflight and Brownell TS, might be different. I believe that is what Allen tested and the B50 is what I had used. I haven't tried the BCY. I believe your right with the micarta overlays. Good luck
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Offline AALLFAB

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Re: fast flight on vintage bows
« Reply #34 on: January 07, 2010, 06:29:00 PM »
I have had a Bear with the string shear through the tip into the limb and a Wing where it sheared off the whole tip like a knife. Jim

Offline artifaker1

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Re: fast flight on vintage bows
« Reply #35 on: January 08, 2010, 09:24:00 AM »
aallfab, no one is denying that one can mess up a bow with FF strings. You probably ought to read a couple of these threads all the way thru. There are people using FF carefully on older bows.
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Re: fast flight on vintage bows
« Reply #36 on: January 08, 2010, 12:37:00 PM »
Larry keep to update us with your review,we appreciate it.Felix
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Offline artifaker1

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Re: fast flight on vintage bows
« Reply #37 on: January 11, 2010, 07:07:00 PM »
Right now the latest update is this one is on the back burner right now. I took the string off the limbs mentioned above, to rethink the situation. The 8125 loops padded to twenty strands are still quite a bit smaller than the 16 strand dacron loops that came off these limbs. I need to find a way to pad the loops  much larger, and I wouldn't mind finding a less expensive bow or limbs to find out intentionally what they won't take first. I still feel the performance and shoot-ability of the bows with 8125 on them is worth it, as long as they don't break that is.
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Offline Ssamac

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Re: fast flight on vintage bows
« Reply #38 on: January 22, 2010, 09:42:00 PM »
The 12 strand string on older bows makes quite a difference on older bows. I found that quite by accident when I bought an old bow with a 12 strand string and was pleasantly surprised.

Give it a try before you put the FF string. Just doesn't pay to damage a nice old bow for very little gain. And yes, they are harder to quiet down.

sam

Offline NYRON

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Re: fast flight on vintage bows
« Reply #39 on: October 09, 2012, 08:29:00 PM »
Hi All:

I'm bringing this to the top to see if there has been any change in experiences or thinking. I've been shooting vintage and custom bows for nearly 20 years.

Until recently, I've always shot B50 on my older bows, but then came my '66 Kodiak. I was having trouble tuning the bow and it just wasn't shooting as well as I thought it should. On a whim I switched the string from B50 to Fast Flight. Wow! What a remarkable difference.

I don't mean speed. It's far more quiet, much more stable after the shot (e.g. less limb vibration), far more consistent in accuracy, and more tolerant of arrow spine. The differences is night and day.

All that said, I have no desire to cleave the tips from my terrific old bows.

So, what's the latest? Are low-stretch strings and old bows still considered incompatible?
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