Primitive Archer
Main Discussion Area => Bows => Topic started by: Hawkdancer on February 17, 2018, 11:16:36 am
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Is there any real advantage to using "Fast Flight" or B55 over B-50, or "Dynaflight 97? I currently use B50. I am assuming that "creep" and "stretch, are the same term. I have a very old fg longbow, an Osage selfbow, a Bear Kodiak Magnum, and a pair of old "ShimBows", haven't worn out a string, as I haven't been shooting that much. Almost always use a stringer to brace. Thanks for your opinions.
Hawkdancer
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Yes. Very many real advantages.
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Got extremely frustrated with B50, Switched to FF, and won't even consider Usin B50 again. FF is cheaper too for the amount of strings you can make from a roll.
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Creep is permanent, stretch is temporary I believe.
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Fast Flight is much faster than B50(i have material in both). Fiberglass trad guys claim that without a hard material tip overlay the non stretch material can crack the tip of the limb. On my primitive bows as well as every glass trad bow ive owned ive never once had this issue. Knock on wood(no pun intended). Have yall had any negative experience regarding this?
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I use nothing but low stretch materials and have for years. Hard to beat in every aspect from durability to cost.
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B-50 is made of polyester no? I once read that polyester has a stiffness (MOE) of around 8 GPa wheras Dynema (which fast flight is made of) has a MOE above a 100 GPa. Now B-50 may be a higher grade polyester than the polyester they may have tested that gave that number i read about, but it illustrates the stark contrast between the two. Even a flax/linen string which is all natural should be stiffer than polyester.
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I read somewhere (one of the bowyer' bibles?) the switching from B50 (polyester) to a fast flight (UHMW polyethylene) material is roughly equivalent to adding 5 pounds of draw weight, in terms of effect on cast. That is, for example, a 45 pound bow with fast flight will shoot an arrow with equal cast as a 50 pound bow using B50. Based on my anecdotal experience with the two, I believe it.
I think the real advantage is that the high stiffness and strength of fast flight material allows you to make a string of fewer strands, which is therefore lighter weight than a B50 string and therefore less of the bow's energy is lost to accelerating the string, leaving more to go into the arrow.
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Maybe this is helpful:
http://primitive-bows.com/about-strings/
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I read somewhere (one of the bowyer' bibles?) the switching from B50 (polyester) to a fast flight (UHMW polyethylene) material is roughly equivalent to adding 5 pounds of draw weight, in terms of effect on cast. That is, for example, a 45 pound bow with fast flight will shoot an arrow with equal cast as a 50 pound bow using B50. Based on my anecdotal experience with the two, I believe it.
I think the real advantage is that the high stiffness and strength of fast flight material allows you to make a string of fewer strands, which is therefore lighter weight than a B50 string and therefore less of the bow's energy is lost to accelerating the string, leaving more to go into the arrow.
Stiffness and tensile strength aren't the same thing. Theoretically you could have a stiff string that broke fairly easy, or a stretchy string that could handle a lot of weight. The higher the tensile strength the less material you need thus reducing weight. The higher the stiffness, the less the string stretches when shooting. Linen string is an example of a material that is stiff but has a lower tensile strength comparatively, especially when dry
Dyneema in fast flight, on the other hand, happens to be both stiff and very strong. Most people with fast flight overbuild their string significantly only for the sake of having a string thick enough to nock well. B-50 has good tensile strength and is probably why it's used so frequently. They tend to be overbuilt as well, when a thinner and lighter string would technically work if it wasn't for nocking purposes. I think the improvement from switching to fast flight is not in weight but stretch.
I made strings from polyester thread, which is technically the same material as B-50, since davron is a brand name for polyester (PET). However, when i videod me firing my wimpy 30 lb bow i saw the string stretched so much that the limbs practically returned to their embraced profile. And despite a 6" brace it just barely missed smacking my wrist. You can try it yourself if you have a new smart phone, to see how much it stretches. I'm not entirely sure how it works but essentially it boils down energy that could have gone to arrow speed is rather lostt in the follow through of the limbs and string stretching
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I've been building wood bows for 30+ years now and have always been satisfied with B-50, B-55, mostly B-50. I've had people try to convince me otherwise but as far as I'm concerned B-50 is good enough for me and my bows.
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I've been building wood bows for 30+ years now and have always been satisfied with B-50, B-55, mostly B-50. I've had people try to convince me otherwise but as far as I'm concerned B-50 is good enough for me and my bows.
Never said it wasn't good enough. It makes fine string material, as will sinew which also stretches quite a bit. But the question was if there was a difference.
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Yes, there is quite a difference.
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Fast Flight is much faster than B50(i have material in both). Fiberglass trad guys claim that without a hard material tip overlay the non stretch material can crack the tip of the limb. Have yall had any negative experience regarding this?
I ripped the entire tip off a 1992 or so 65lb Martin Hunter (made pre-FF era) when I had an arrow nock split, causing a dryfire. The string split the top limb lengthwise into three sections, from the deepest part of the string nocks down about 3" down into the fiberglass,. Basically it ripped about a 1/2" splint out of the middle of the limb, leaving splints on each side.
Most bowyer upgraded their limb tips short after with linen micarta, carbon, and phenolic overlays to shoot FF, but I would be careful using it on older "classic" bows from the 60's, 70's, and 80's.
However, on wooden bows, I have never had a problem. I think most designs just don't store the energy something like a high draw weight FG deflex/ huge recurve does, so I use bot low stretch veg fibers and FF on my selfbows, too. If I make overlays, I use multiple thin layers and very strong glue, so the grain of each sits at a slight bias (sort of like plywood, I guess?) I also learned not to make overlays from wood that is super soft or splits easily. BLOCUST is very strong, but will split clean and easy, as will black walnut.. So will some exotics like purple heart. Mulberry heartwood or pear won't so much.
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Big difference. I only use fastflight or D97. I would like to learn to work with linen at some point but have no interest in using b50.
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All my bows draw 50# or less, my draw is 26 1/2 and I try for fistmele of 6", so I don't think I would be straining any of them with a faster string material. Is it a safe assumption that blending materials such as B50 and FF, is a reasonable experiment or is it a waste of time and materials?
Hawkdancer
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All my bows draw 50# or less, my draw is 26 1/2 and I try for fistmele of 6", so I don't think I would be straining any of them with a faster string material. Is it a safe assumption that blending materials such as B50 and FF, is a reasonable experiment or is it a waste of time and materials?
Hawkdancer
I made a string recently that was made of polyester thread and dyneema fishing line. I made it as a flemish twist, with roughly half of it being one and the other half being the other. What happened interested me. It ended up creeping about as much as polyester alone, so I had to readjust my knot as the length changed. However, once it finished creeping, it didin't stretch much anyomore, not nearly as much as if it had been just polyester. After the creep I believe it had a stiffness closer to pure dyneema. What i'm guessing happenend was that the creep was the polyester stretching and thining, as the spiraling of the flemish flatened out as straight as possible. So after that initial creep, the polyester stretched as far as it could before the dyneema was forced to work, but once that happened i think the dyneema took over the load entirely (so it was important that there was enough dyneema to handle the entire tensile load alone). I don't think mixing the two is as simple as 1 + 3. Because they stretch at different rates and have different tensile strengths. i think instead of getting 4 from combining them you get something like 1 then 3.
I don't think i'll mix different string material again unless I needed to get rid of one and use it to get the string thick enough. I personally found the creep annoying and would prefer to avoid that by going straight dyneema. But it does work if you want to do it that way just make sure you have enough strength for it, which most strings of common thicknesses will suffice by plenty.
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I've always used 14 strands of B-50, but I think I'll try FF or D97. How many strands should I use of these materials for up to 75#?
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I use 8 strands up to 50'ish and 10 strands up to 65ish. For a 75# bow Id lean towards 12 strands. You can actually drop all those down two strands if you care to, I like a little wiggle room.
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What serving material works best with FF or B55? Also, is it necessary to pad the nocking area and tip loops/tail area, and how much? Currently make just endless loop strings.
Hawkdancer
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I like the good stuff, I think its called diamondback. I also like using .025" or bigger. Otherwise it requires a lot of build up to get an arrow to snap on.
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I am with Pearl on the string. I was on the B50 side for along time until Rick Barby convinced me to try ff . Got rid of all my b50 and never looked back. Arvin
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I have an old Bear Green Fox" (56"/45#) all-glass bow from the ~1960's that has a fast-flight string... is that why it has so much hand shock? It's otherwise a pleasant little bow to carry and shoot on super rainy days.
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Odds are your brace height needs tweaking. Bump it up a 1/4" at a time and I bet you find a sweet spot sooner than later.
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OK, I'll give that a try.
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Where do people get their Fast Flight or D97?
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Where do people get their Fast Flight or D97?
I get mine from the vendors at the Tennessee Classic.
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3Rivers carries and ships fairly quickly. Ordered some We'd and it shipped Wed. Don't get to the Classic and we don't have one out here - yet!
Hawkdancer
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I have not had that much success in properly pre-stretching B50 (maybe I have not added enough weight to do it right). I have quit using B50 and switched solely to FF because it was hard for me to make flemish twist strings from B50 due to the subsequent stretching of the string. I much prefer FF, it simply stretches very little and in order to protect the self bows I use 8-14 strands of FF (depending on the draw weight of the bow).
I double up the strands for the flemish twists so the FF string does not cut into the self nocks. I am using HHB and I don't have to reinforce the self nocks using FF and I have never had a bow failure due to using FF.
I do believe that my bows are definitely snappier with FF verses B50
This is just my experience.
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I like the low stretch materials fine, but I have come to realize that the craftsmanship - the string maker's ability - means as much as the choice of materials. I am a work in progress. My strings are much better than they used to be, but I have to admit on my dedicated hunting bows, I don't trust my own ability and generally buy a string from someone who makes a good one. Dang, I hate to admit that! A really well made B-50 string, with just the right amount of strands and twists, properly stretched out and not over built, shoots really good. With that said, my main hunting bow right now has fast flight on it.
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Thanks for all the info! I will be trying to make a FF string for the Osage "Transdextramation." It needs a shorter string, And the hickory that is in the tillering stage.(more scraping to do) Which crisis is the highest priority!? " "transdex" pulls 43# and the target for the hickory is about 45#.
Hawkdancer