460 0 #1 April 4, 2006 What is break cord made of? Does anyone know what the elongation or stretch percentage is? thanks, ChrisLooks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174 Share this post Link to post Share on other sites
cornishe 0 #2 April 4, 2006 QuoteWhat is break cord made of? Cotton. Quote Does anyone know what the elongation or stretch percentage is? dunno. -amAbbie Mashaal Skydive Idaho Snake River Skydiving TandemBASE Share this post Link to post Share on other sites
JaapSuter 0 #3 April 4, 2006 Don't have a percentage for you, but we experimented with break cord in a tensile tester and noticed it barely stretches and then just snaps suddenly. So whatever the percentage is, it's not going to be very high. Not sure if that's useful, but there you have it anyway... Share this post Link to post Share on other sites
980 0 #4 April 4, 2006 Shouldn’t we be asking you that question? As the physics professor surely you have colleagues and/or acquaintances with access to a materials testing lab and it would be a 15 minute job to run 20 or so samples through a tensile strength tester. I have no data to offer, but I do support the qualitative answer of: ‘not very much at all’ based on some uninstrumented testing I have done. I hope somebody actually tests this and posts the answer, I’m curious now. Share this post Link to post Share on other sites
460 0 #5 April 4, 2006 yes, I could repeat reinventing the wheel but their should be well measured spec's already.Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174 Share this post Link to post Share on other sites
980 0 #6 April 4, 2006 May I ask why you are interested in this information? I’m pretty sure that for a standard BASE static line breakcord loop set-up with a surgeon’s knot, you will see the loop length increase in size more due to the knot tightening up than due to the elongation of the cotton tape. And by standard I guess I mean breakcord loop 1 to 3 inches in length between tie-off and link. Share this post Link to post Share on other sites
460 0 #7 April 4, 2006 Because breakcords can be easily misused with potentially fatal results. I'm trying to come up with a recommended break cord strength versus length of fall before loading occurs. For example, if you take 10 feet of break cord and drop 10 pounds on the end of it, it will break. The 80lbs force to break is related to elongation and is a static force specification. The specs for using a break cord for providing a virtual PCA require the jumper to consider the length of the cord and where it's attached. I saw a photo recently of what appears to be a misuse.Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174 Share this post Link to post Share on other sites
TomAiello 26 #8 April 4, 2006 QuoteBecause breakcords can be easily misused with potentially fatal results. I'm trying to come up with a recommended break cord strength versus length of fall before loading occurs. For example, if you take 10 feet of break cord and drop 10 pounds on the end of it, it will break. The 80lbs force to break is related to elongation and is a static force specification. The specs for using a break cord for providing a virtual PCA require the jumper to consider the length of the cord and where it's attached. I saw a photo recently of what appears to be a misuse. You should ask the Apex folks what they learned when doing test drops for the SuperBowl demo.-- Tom Aiello Tom@SnakeRiverBASE.com SnakeRiverBASE.com Share this post Link to post Share on other sites
JaapSuter 0 #9 April 4, 2006 QuoteI saw a photo recently of what appears to be a misuse. Can you elaborate on this? I've heard of people extending their static-lines by as much as twenty feet without problem. I can see how a longer delay will increase the snatch force and increase chances of a premature break though. Is that what you're getting at? Share this post Link to post Share on other sites
monkey1031 0 #10 April 4, 2006 Every jumper I've ever talked to about breakcord recommends a surgeons knot... I'm curious as to why no one is using a water knot? Seems like a better choice, and it's the one I used, and continue to recommend. Criticism welcome.. -smd7 Share this post Link to post Share on other sites
460 0 #11 April 4, 2006 http://www.scoutingresources.org.uk/downloads/knots_waterknot.pdf They suggest using a water knot for flat lines since I suppose they don't slip compared to round lines. How are you using a water knot since you are not joining to equally sized lines?Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174 Share this post Link to post Share on other sites
TomAiello 26 #12 April 4, 2006 QuoteHow are you using a water knot since you are not joining to equally sized lines? The water knot is used to join the break cord to itself.-- Tom Aiello Tom@SnakeRiverBASE.com SnakeRiverBASE.com Share this post Link to post Share on other sites
vid666 0 #13 April 4, 2006 because that's not the easiest knot to tie when it's dark ? Because what most people already do, works well, and complicating the system = asking for trouble. Keep It Simple Stupid Share this post Link to post Share on other sites
monkey1031 0 #14 April 4, 2006 I used the water knot and tie it as a loop (just like 1" tubular for climbing), I make (made) two loops, one smaller than the other, both loops through the bridle & pilot chute and those are clipped with a locking crab to a supertape sling to whatever object we were jumping from. that dosn't make a bit of sense... I'll try to get a pic. -smd7 Share this post Link to post Share on other sites
460 0 #15 April 4, 2006 Ah, gotcha!Looks like a death sandwich without the bread - Steve Deadman Morrell, BASE 174 Share this post Link to post Share on other sites
980 0 #16 April 4, 2006 surgeon's knot is what is traditionally tought the only reason I can think of why, is the security of the knot and the low reduction in strength due to the knot water knot looks good too I've done an overhand knot in some. I even girth hitched the loops of breakcord directly to hole in a metal plate on the object and that worked too. If anyone is exceedingly curious about some static line testing, I will be in the Twin from 21-29 April and one of the things I am going to do is play around with some static line techniques. Let me know if there is any test jumps I could do that would be of interest you. FWIW I have been using two different sized loops of breakcord on all my static line jumps from Oct 05 and have not noticed any ill effects. The extra loop does give me that warm and fuzzy feeling when exiting, though. Share this post Link to post Share on other sites
edge01 1 #17 April 4, 2006 Check the poynters manual it may have more info. Share this post Link to post Share on other sites nicknitro71 0 #18 April 4, 2006 Chirs, It's around 7.5%.Memento Audere Semper 903 Share this post Link to post Share on other sites Faber 0 #19 April 5, 2006 QuoteLet me know if there is any test jumps I could do that would be of interest you. i would like to know the headding preformance on a SL jump were you do an arial.. like a front flip or standing floater way and do a reverse salto/gainer but jumping backwards Let me know how it goes and please get some video PS make sure to clear the bridel Stay safe Stefan Faber Share this post Link to post Share on other sites 980 0 #20 April 5, 2006 dude I was totally going to do that anyway! Just ask anyone who has seen the ‘Ho-Bag’. I will happily send experienced jumpers the footage, along with an essay on why it’s bad idea. I won’t be the first person to have done static line aerials, though… Share this post Link to post Share on other sites Faber 0 #21 April 5, 2006 QuoteI will happily send experienced jumpers the footage, along with an essay on why it’s bad idea. damnit hope you will ship to me aswell anyway you´ll get pm in a sec or two Stay safe Stefan Faber Share this post Link to post Share on other sites 980 0 #22 May 9, 2006 hey hey I didn't get around to doing any straight static line aerials, but two new versions of the Ho-bag and I think they qualify. one even used some breakcord... see it here cya Share this post Link to post Share on other sites Faber 0 #23 May 9, 2006 Ha Ha nice one,if posible i would like to buy a copy as the vid is done Stay safe Stefan Faber Share this post Link to post Share on other sites 0 Go To Topic Listing
nicknitro71 0 #18 April 4, 2006 Chirs, It's around 7.5%.Memento Audere Semper 903 Share this post Link to post Share on other sites
Faber 0 #19 April 5, 2006 QuoteLet me know if there is any test jumps I could do that would be of interest you. i would like to know the headding preformance on a SL jump were you do an arial.. like a front flip or standing floater way and do a reverse salto/gainer but jumping backwards Let me know how it goes and please get some video PS make sure to clear the bridel Stay safe Stefan Faber Share this post Link to post Share on other sites
980 0 #20 April 5, 2006 dude I was totally going to do that anyway! Just ask anyone who has seen the ‘Ho-Bag’. I will happily send experienced jumpers the footage, along with an essay on why it’s bad idea. I won’t be the first person to have done static line aerials, though… Share this post Link to post Share on other sites Faber 0 #21 April 5, 2006 QuoteI will happily send experienced jumpers the footage, along with an essay on why it’s bad idea. damnit hope you will ship to me aswell anyway you´ll get pm in a sec or two Stay safe Stefan Faber Share this post Link to post Share on other sites 980 0 #22 May 9, 2006 hey hey I didn't get around to doing any straight static line aerials, but two new versions of the Ho-bag and I think they qualify. one even used some breakcord... see it here cya Share this post Link to post Share on other sites Faber 0 #23 May 9, 2006 Ha Ha nice one,if posible i would like to buy a copy as the vid is done Stay safe Stefan Faber Share this post Link to post Share on other sites 0
Faber 0 #21 April 5, 2006 QuoteI will happily send experienced jumpers the footage, along with an essay on why it’s bad idea. damnit hope you will ship to me aswell anyway you´ll get pm in a sec or two Stay safe Stefan Faber Share this post Link to post Share on other sites
980 0 #22 May 9, 2006 hey hey I didn't get around to doing any straight static line aerials, but two new versions of the Ho-bag and I think they qualify. one even used some breakcord... see it here cya Share this post Link to post Share on other sites
Faber 0 #23 May 9, 2006 Ha Ha nice one,if posible i would like to buy a copy as the vid is done Stay safe Stefan Faber Share this post Link to post Share on other sites
