Excalibur Excel Crossbow String or flemish string?
#11
Spike
Join Date: Mar 2008
Location:
Posts: 43

ORIGINAL: smokepolehall
if you want 30 in and endless loop you go 15 full wraps, 15 on each side, 2 sides 30 stands. its the End loops,that will only have 15 strands that will be weaker
if you want 30 in and endless loop you go 15 full wraps, 15 on each side, 2 sides 30 stands. its the End loops,that will only have 15 strands that will be weaker
The loop of an endless loop string is EXACTLY as strong as the string itself. True, it has half the strands, but the tention on the string is equaly devided between the two "glands" of the loop. So half the strands carry half the load. (It's also truefor the very tip of the loop)
This is basic mechanical engineering (and I had my share...)
Indeed, the flemish has stronger loops than the endless, but having a loop twice as strong as the string, has no value.
It may have some value if there isserious stress consentration in the loop, like around sharp cornets. But I suspect that's not the case thanks to the cushioning provided by the serving, and the elasticity of the string (in dacron).
It does puzzle me why is the concensus that flemish is faster (not that I know otherwise). Flemish is much more twisted than endless, so it's bound to have more mass per inch. It has more surface, and a non-smooth one (ie, less airodynamic).
So how can a heavier string with more drag be faster?
#12
Nontypical Buck
Join Date: Feb 2006
Location: arkansas
Posts: 3,147

It does puzzle me why is the concensus that flemish is faster (not that I know otherwise). Flemish is much more twisted than endless, so it's bound to have more mass per inch. It has more surface, and a non-smooth one (ie, less airodynamic).
The reason FFF is faster than endless loop is the string matl doesn't stretch as much on the shot cycle, not due to the loop type.
It wasn't until the last year or so the custom string makers like "Boo" and a few others offered them for the public. Now, you can get virtually any thing from them and it's kinda blurred the basic differences in strings from what was once only simple mass produced choices from the factories in the past.
I take it you may be an engineer? Haven't you guys proved bumble bee's and helicopters can't actually fly?



#13
Giant Nontypical
Join Date: Feb 2003
Posts: 9,175

I'm sure from an engineering standpoint, the loops in endless strings are just as strong as the body of the string. But I question your contention that "having a loop twice as strong as the string has no value." Two reasons: 1) I've had many endless loop strings break, nearly ALWAYS in one loop or the other and only very rarely in the body. 2) Not one single flemish string has ever broken on one of my bows.
Now, it might be possible the reason for that is you can readily see when the loop is damaged with a flemish string while any damage to an endless loop is hidden under the serving. That's a visual indicator to tell you it's time to change the string. Or, when several strands are damaged in the loop, an endless string could be weakened enough to break while the extra strands in a flemish loop give you built in redundant safeguards to keep it from breaking.
Either way, there is a real, tangible value to flemish strings' stronger loops.
Now, it might be possible the reason for that is you can readily see when the loop is damaged with a flemish string while any damage to an endless loop is hidden under the serving. That's a visual indicator to tell you it's time to change the string. Or, when several strands are damaged in the loop, an endless string could be weakened enough to break while the extra strands in a flemish loop give you built in redundant safeguards to keep it from breaking.
Either way, there is a real, tangible value to flemish strings' stronger loops.
#14

At the loop there is twice the tensile strength because there is twice the thread count. There is twice the cushioning as well. But the main thing is that there is twice the number of string material to wear/abrade against each other which really is the biggest problem which is of course accelerated by everyone's lack of maintenance. Flemish strings, by virtue of their construction(twist) decelerate the string in a more gentle manner by acting as a shock absorber. The ripping and rubbing of the strands against each other is not nearly as violent.