monkeybot 0 #1 December 16, 2002 Ok, This is not a flame but my personal experience. I got about a 1000 jumps. I weight 190 at the door. I have about 600 jumps on stilletos. I currently own 2 stilettos 120's plus the comp cobalt. I had an opportunity to get a used Comp Cobalt 95 (150 jumps) so I did, I want it something fast to swoop that I could land without hooking it everytime. The previous owner told me that the openings were brisky. I am a tough guy so I said to myself it means pack it better. I have a 24" cazer pilot chute, I dump in track, hop'n'pops, 12 + rolls on the tail, shove the nose all the way in. I don't know what else. Every single opening is brisky to say the least. Every weekend my neck is so sore that I think my head is going to roll out of my body on every opening. I am sore today. I was the week before and the week before that one. And the worst is if I tried to look at my opening...God save me... whiplash. I have tried to video my openings and all I got is me filming my feet. I have done everything Atair's site says to do, relax, dump in track don't grab the risers, etc... I have now 20 jumps on the canopy and it flies. I mean IT FLIES. it is fast, dive nice, good riser input. I have landed straight in, double fronts and last weekend I started to carve it to get used to (Way different than my stiletto) but I can't pass on the openings and I am ready to dump the sucker. Oh well, maybe the regular Cobalt is what everybody praises. This 95 is not. My Sabre 170 was sweet compared to this one on openings. -------------------------------- I have no friends under 2K Quote Share this post Link to post Share on other sites
PhreeZone 20 #2 December 16, 2002 Call Dan at Atair and talk to him about the canopy. I personally never pushed or did anything with the nose of my Cobalt. Left it hang and it opened much better then when I tried messing with it.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
diveout 0 #3 December 16, 2002 You could have a rigger modify the slider (like sew a pocket on it) I know of at least two people who've had this done with good success. Quote Share this post Link to post Share on other sites
AggieDave 6 #4 December 16, 2002 QuoteYou could have a rigger modify the slider (like sew a pocket on it) That's what I call a band-aid fix. You're not addressing the real problem, you're just sort of covering it up. He really should contact Dan Preston about it. If anything Dan always says if someone has a canopy that does that, he fixes them for the customer.--"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites
Spy38W 0 #5 December 16, 2002 QuoteCall Dan at Atair and talk to him about the canopy. I personally never pushed or did anything with the nose of my Cobalt. Left it hang and it opened much better then when I tried messing with it. I agree on both points. I found that leaving the nose hanging without stuffing it into the packjob gave me the best openings on the Cobalt. -- Hook high, flare on time Quote Share this post Link to post Share on other sites
cobaltdan 0 #6 December 16, 2002 "You could have a rigger modify the slider" i hate this common fudge suggestion. it only comes into play if the canopy manufacturer will not stand behind their product or if someone lacks the common sense to contact the manufacturer in the first place. if you have a problem with a canopy, do not take it upon yourself to try and fix it. please contact the manufacturer. used canopies rarely have the stated # of jumps on them. it is probably out of trim, simply contact us and we will be glad to sort you out. sincerely, dan atair aerodynamics www.extremefly.com 718-923-1709 phDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
bwilling 0 #7 December 16, 2002 Quote"You could have a rigger modify the slider" i hate this common fudge suggestion. QuoteThat's what I call a band-aid fix. You're not addressing the real problem, you're just sort of covering it up. Why is this fix any worse than the suggestion of a smaller pilot chute, or a larger slider, to tame hard openings? If I call PD and tell them my Sabre opens hard, and they provide a bigger slider (or someone calls Atair about a Cobalt, and they suggest a smaller pilot chute), and it corrects the openings, is that a bad thing?!? "If all you ever do is all you ever did, then all you'll ever get is all you ever got." Quote Share this post Link to post Share on other sites
Jimbo 0 #8 December 16, 2002 QuoteWhy is this fix any worse than the suggestion of a smaller pilot chute, or a larger slider, to tame hard openings? If I call PD and tell them my Sabre opens hard, and they provide a bigger slider (or someone calls Atair about a Cobalt, and they suggest a smaller pilot chute), and it corrects the openings, is that a bad thing?!? Kind of what I was thinking, fixed is fixed. - Jim"Like" - The modern day comma Good bye, my friends. You are missed. Quote Share this post Link to post Share on other sites
AggieDave 6 #9 December 17, 2002 I was hinting at something there...that if you're having to jump through hoops to get good openings, then there's probably a problem somewhere, and you should talk to the manufacture. When I bought my Heatwave, I ordered a larger slider for it (from PISA). People I've talked to who didn't do that, still have great openings, but mine are seriously sweet with the larger slider. In this instance, not a fix, just a mod to suit my taste. I point that out, since I'm sure someone would have brought that up in this thread at some point or another and have tried to call me a hypocrit.--"When I die, may I be surrounded by scattered chrome and burning gasoline." Quote Share this post Link to post Share on other sites
Zlew 0 #10 December 17, 2002 I don't think you should have to do any "crazy" ((and no a big slider from the manufac isn't a crazy mod)mods to a canopy to make it open well. I sugest buying another canopy before you have someone put pockets on your slider. I'm with Dave.... you shouldn't have to do that sort of stuff. I had a friend who had a "test" Viper that had velcro, yes, velcro to shut the nose for softer openings. If you feel like you have to try shit like that to make a canopy work for you.........I say FUGH DAT! It's true...the video of the Viper openning so hard that it knocked his shoes off....or the one where his helmet came off (caught it upside down) are pretty bad.... but I'd use the thing for a car cover or to start a fire with before I had the Manufac. send me one with velcro on the nose! Jaime, I hope it is just out of trim. and uh....I'll jump it a little later.... hop n pop maybe.........hehe Z Quote Share this post Link to post Share on other sites
bwilling 0 #11 December 17, 2002 Velcro on the nose, huh? I'm not just arguing for the sake of arguing... I have a Sabre that sombody else (the previous owner) put a pocketed slider on it, and I don't know whether it was knee-jerk reaction to a hard opening, or what, but it was on there when I purchased the canopy, and I know of at least two experienced canopy pilots that post here that have recommended that to people (does that make them crazy?). But if you read my thread in Gear and Rigging, you'd know that I'm not happy with the openings on my Sabre, I think the thing snivels way too long, and suspect that it's related to the pocketed slider. I also wonder if the pocketed slider is really even necessary, or if a big standard slider would be fine (and I will likely find out). Hell, any canopy can open hard, with line dump and premature slider drop (before the canopy actually inflates and forces it down the lines) being the two biggest culprits. PD's stance (I talked to Scott Miller at PD before I bought the canopy), is that the Sabre is very "unforgiving" of the kinds of packing "sloppines" that cause hard openings in general, thus their reputation for hard openings. I do agree that you have to draw the line somewhere, I just don't think that adding a lip to the slider is inherently any crazier than requiring a certain size pilot chute, or a larger slider... But velcro on the nose, now that's crazy! "If all you ever do is all you ever did, then all you'll ever get is all you ever got." Quote Share this post Link to post Share on other sites
cheneyneel 0 #12 December 17, 2002 QuoteQuote That's what I call a band-aid fix. You're not addressing the real problem, you're just sort of covering it up. Guys modifying a slider is not (not) addressing the issue. Ask any experienced BASE jumper and he or she will tell you that the slider dictates EVERYTHING on openeing.. A bigger slider or a pocket slider could work very well and if it does than it WORKS. Who knows if the one on there is too small in the first place.. But if it still wacks you and you cant send it back because of the holidays put a pocket slider or a bigger one on it and stop dumping in a track. If it is out of trim you are just making it worse with the hard openings..... Quote Share this post Link to post Share on other sites Hooknswoop 19 #13 December 17, 2002 QuoteHell, any canopy can open hard, with line dump I have seen lots and lots of videos of deploying canopies. Some of them were very hard openings. I have never seen video of line dump or talked to someone that has. I posted a while back asking if anyone had video of line dump. I think I got two responses neither could actually put their hands on the video. Edited, found my original post http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=271898;search_string=line%20dump;#271898 One reply of a tandem line dump. Heavy lines, wide bag, packers, one heck of a PC (collasped drogue) "Line Dump What is it? Line dump is when the pilot chute pulls hard enough on the bad and/or the line stows that hold the bag closed are loose and or small enough that the canopy is yanked out of the bag before the lines are taut. The canopy begins to inflate and then the lines go taunt, resulting in an extremely hard opening. The opening could result in injury and/or equipment damage (broken lines, torn fabric, etc) For this to happen, the line stows that hold the deployment bag shut must be released before the line tension would release them normally. If the other, non-locking stows released early, the only difference should be a faster, not harder opening. How loose would the locking stows have to be? That depends. Size of the deployment bag, distance between the locking stows, weight of the bag, amount of force the pilot chute delivers at your opening speed are all factors. Taking some measurements on an old Sun Path Javelin J3 main deployment bag, I found that the bag is 13 inches wide. This is how far apart the line stows are. The locking stows are 5 inches apart. If you make 2 inch line stows, you have 8 inches of line on the outside of 2 bands with 13 inches on line between the bands. So there is 5 inches more line between the band. Since there is more line between the stows of the stows, the line between the stows is heavier and if you accelerated the bag enough, the lines would be pulled out of the stows, creating line dump. The line stow bands would have to be loose or the bag accelerated at a pretty high rate to achieve this. The heavier the line and the farther apart the stows, the bigger the problem. Why not make line stows that put an equal amount of line outside the stow as inside? The larger the stow, the larger the chance that one stow could find its way inside another stow, creating a bag-lock. Also, larger line stows tend to turn the bag. As a line is pulled out of the stow, the bag is tilted at an angle and is exposed to the relative wind and it is easy for the bag to spin. The same thing happens with very tight stows, the bag spends more time tilted at an angle, possibly being spun by the wind. Now look at the old style J3 bag again. The locking stows are 5 inches apart. If you make 2 inch stows, there is 8 inches of line outside the stows and 5 inches between the stows. The line outside the stows is heavier and high acceleration of the deployment bag does not tend to create line dump. Acceleration tends to hold the stows in place until line tension pulls them out. Only if the locking stows were to break allowing the canopy to come out of the bag could the canopy open hard. Looking at a Sun Path Javelin J3 reserve free-bag, the locking stows are only 4 inches apart. With 2 inch locking stows, there is 4 inches of line outboard of each stow and 4 inches of line between stows. There an even amount of weight inboard and outboard of the stows. So even loose stows shouldn't result in line dump and a hard opening. Looking at reserve packing instructions, I found the Dolphin manual says 2-3 inch locking stows, the Mirage manual says 2 inches for micro-line and up to 3 inches foe Dacron line, and the Reflex manual says 1 ½ inch locking stows." I believe canopies inflate in 3 "stages" Stage 1- once he canopy is out of the bag, it will "snivel" until the nose catches a bit of air and it begins to pressurize, making the bottom skin slightly larger than the slider. Stage 2- The bottom skin begins to inflate, out-pacing the pressurization of the canopy. The slider slides down the lines Stage 3- Canopy pressurization. I think hard openings are caused by; high speed deployments, Stage 1 initial pressurization being too much/too fast, exposing too much of the bottom skin around the slider, creating a faster stage 2 bottom skin inflation, pressurization catching up to bottom skin inflation which forces the slider down the lines too quickly and causes stage 2 and 3 to happen simultaneously, or not keeping the slider all the way up against the stops. A canopy that has a pocketed slider that takes too long to open can be very easily fixed by making the pocket smaller or removing it. If it is a large pocket I would recommend making it smaller (sewing across it and trimming the excess), if it a small pocket, remove it. Hook Quote Share this post Link to post Share on other sites freeflyguy 0 #14 December 17, 2002 Whoa! I tend to not agree with some of your swoop methods, but that is a good analysis of canopy deployment. ---------------------------- bzzzz Quote Share this post Link to post Share on other sites Unutsch 0 #15 December 17, 2002 Quote Call Dan at Atair and talk to him about the canopy. I personally never pushed or did anything with the nose of my Cobalt. Left it hang and it opened much better then when I tried messing with it. that's what i do with my Ace 100 (also Atair, sold as Viper in the states), and now i get allmost every time nice openings, some are real FAST, but not neckbracking... that's what i learned from this forum, i also asked some experienced jumpers here in Slovenia about that, and since no one had anything bad to report, i went on with it, and lived happily ever after! Check out the site of the Fallen Angels FreeflY Organisation: http://www.padliangeli.org Quote Share this post Link to post Share on other sites roq 0 #16 December 17, 2002 With certainty you have a trim or packing problem in the canopy. When have correct trim and packing the cobalt is the best openning canopy of the World! I have more than 700 jumps with atair Cobalt and Impulse 75, 85 and 120 and never had any hard openning. Normal the CC and H-mod cobalt has still more soft opennings than original cobalt Don't modifies slider or other in your canopy. Ask Dan Preston from Atair about your problem. If you have interest in my packing see attach. roq Quote Share this post Link to post Share on other sites bwilling 0 #17 December 17, 2002 Very nice analysis of opening sequence Hook! I started jumping back in 1978, and jumped thru about 1983 or so, and don't remember hard openings being such a hot topic back then... oh, canopies varied in deployment speed, sure, but I don't recall people having openings so hard it hurt them (other than my now ex-wife, who used to get some horrific inner thigh bruises from the Starlite she jumped!). But lots has changed since then... canopy fabric and line materials are different, freefall speeds are way up (even for belly flying!), and I wonder if those changes aren't at least in part responsible for the tendency towards hard openings? It's interesting to note that I have a copy of SDU's Basic Body Flight Video, and if you watched the openings that are part of the video (it's old, I think they're all Sabres they're jumping, as PD was a sponsor), the openings range from one that is sweet as candy, to one that looked like it had to hurt! A very night and day difference between the two, but I don't have the experience to really analyze why they vary so much (and not sure if you could slow the video down enough anyway)... QuoteA canopy that has a pocketed slider that takes too long to open can be very easily fixed by making the pocket smaller or removing it. If it is a large pocket I would recommend making it smaller (sewing across it and trimming the excess), if it a small pocket, remove it. Thanks, I'll try having my rigger shrink that lip down in size (it's prolly at least 2 - 2.5 inches right now), and see what that does to my openings). I know everybody thinks the old Sabres are boats, but it's all relative... loaded 1.2ish, it's the smallest , highest performance canopy that I've ever jumped! And other than the too long snive on openingl, I like the thing... "If all you ever do is all you ever did, then all you'll ever get is all you ever got." Quote Share this post Link to post Share on other sites freeflyz 0 #18 December 17, 2002 two words ICARUS CROSSFIRE!!!!!!!!!!! Quote Share this post Link to post Share on other sites cobaltdan 0 #19 December 17, 2002 hook, something to consider that most people do not realize is that the first shock you feel when deploying a canopy is at line stretch before your canopy is out of the bag. this shock is caused by the pilot chute, not the canopy. if this defination is acceptable as line dump i have quite alot of proof as to it happening both video and datalogged jumps. as the opening sequence is a series of fast shocks a jumper is usually incorect when recounting what happened in the analysis of a jump. i.e. 10 different pilots, 10 jumps, same single canopy, and you will get 10+ different accounts of how it opened. probably none of which match the recorded datalogged sensor data. the most dramatic recorded instance of the above was 29g's at line stretch and then 6.4g peak once the canopy came out of the bag. improperly sized pilots especially at higer speeds can definately rock you harder than you canopy. sincerely, dan<><> www.extremefly.com sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites Hooknswoop 19 #20 December 17, 2002 Quotesomething to consider that most people do not realize is that the first shock you feel when deploying a canopy is at line stretch before your canopy is out of the bag. this shock is caused by the pilot chute, not the canopy. if this defination is acceptable as line dump i have quite alot of proof as to it happening both video and datalogged jumps. I think the common defination of line dump, is the PC pulling hard/fast enough that the locking stows come un-done before the canopy comes out of the bag. This allows tha canopy to begin inflating before the lines are taut. I think line dump is extremely rare and is blamed for hard openings when it isn't the culprit. Quotethe most dramatic recorded instance of the above was 29g's at line stretch and then 6.4g peak once the canopy came out of the bag. So, you are saying a bag lock can produce 29 G's? Hook Quote Share this post Link to post Share on other sites cobaltdan 0 #21 December 17, 2002 i am saying that i have video and sensor data logged showing a 29g's at line stretch with canopy completely in the bag. the peak width is 4 miliseconds. then a completely new peak of 6.4 g's when the canopy exits the bag and catches air (6.4 stage 1, droping to 3.5g's stage 2, width 5 seconds). sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites Hooknswoop 19 #22 December 17, 2002 PC size?, Deployment speed? Suspended weight? I find a PC and bag producing 29 G's amazing. I'm guessing this wasn't a live person being subjected to those forces. Hook Quote Share this post Link to post Share on other sites cobaltdan 0 #23 December 17, 2002 it was a military tandem drop... as i said the most pronounced example. sincerely, danDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites diablopilot 2 #24 December 18, 2002 Quoteit was a military tandem drop... as i said the most pronounced example. So on a drouge? Did it collapse? 4 miliseconds? What was it 1/2 a second after peak? Interesting data. Interpretation is the key. -jp----------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites cobaltdan 0 #25 December 18, 2002 http://www.extremefly.com/aerospace/press/index.html# click on "slow motion with video". it is a little hard to see the data trace in compressed form... force from line stretch droped almost back to base line before increasing again for opening shock.sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites Prev 1 2 Next Page 1 of 2 Join the conversation You can post now and register later. If you have an account, sign in now to post with your account. Note: Your post will require moderator approval before it will be visible. Reply to this topic... × Pasted as rich text. Paste as plain text instead Only 75 emoji are allowed. × Your link has been automatically embedded. Display as a link instead × Your previous content has been restored. Clear editor × You cannot paste images directly. 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Hooknswoop 19 #13 December 17, 2002 QuoteHell, any canopy can open hard, with line dump I have seen lots and lots of videos of deploying canopies. Some of them were very hard openings. I have never seen video of line dump or talked to someone that has. I posted a while back asking if anyone had video of line dump. I think I got two responses neither could actually put their hands on the video. Edited, found my original post http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=271898;search_string=line%20dump;#271898 One reply of a tandem line dump. Heavy lines, wide bag, packers, one heck of a PC (collasped drogue) "Line Dump What is it? Line dump is when the pilot chute pulls hard enough on the bad and/or the line stows that hold the bag closed are loose and or small enough that the canopy is yanked out of the bag before the lines are taut. The canopy begins to inflate and then the lines go taunt, resulting in an extremely hard opening. The opening could result in injury and/or equipment damage (broken lines, torn fabric, etc) For this to happen, the line stows that hold the deployment bag shut must be released before the line tension would release them normally. If the other, non-locking stows released early, the only difference should be a faster, not harder opening. How loose would the locking stows have to be? That depends. Size of the deployment bag, distance between the locking stows, weight of the bag, amount of force the pilot chute delivers at your opening speed are all factors. Taking some measurements on an old Sun Path Javelin J3 main deployment bag, I found that the bag is 13 inches wide. This is how far apart the line stows are. The locking stows are 5 inches apart. If you make 2 inch line stows, you have 8 inches of line on the outside of 2 bands with 13 inches on line between the bands. So there is 5 inches more line between the band. Since there is more line between the stows of the stows, the line between the stows is heavier and if you accelerated the bag enough, the lines would be pulled out of the stows, creating line dump. The line stow bands would have to be loose or the bag accelerated at a pretty high rate to achieve this. The heavier the line and the farther apart the stows, the bigger the problem. Why not make line stows that put an equal amount of line outside the stow as inside? The larger the stow, the larger the chance that one stow could find its way inside another stow, creating a bag-lock. Also, larger line stows tend to turn the bag. As a line is pulled out of the stow, the bag is tilted at an angle and is exposed to the relative wind and it is easy for the bag to spin. The same thing happens with very tight stows, the bag spends more time tilted at an angle, possibly being spun by the wind. Now look at the old style J3 bag again. The locking stows are 5 inches apart. If you make 2 inch stows, there is 8 inches of line outside the stows and 5 inches between the stows. The line outside the stows is heavier and high acceleration of the deployment bag does not tend to create line dump. Acceleration tends to hold the stows in place until line tension pulls them out. Only if the locking stows were to break allowing the canopy to come out of the bag could the canopy open hard. Looking at a Sun Path Javelin J3 reserve free-bag, the locking stows are only 4 inches apart. With 2 inch locking stows, there is 4 inches of line outboard of each stow and 4 inches of line between stows. There an even amount of weight inboard and outboard of the stows. So even loose stows shouldn't result in line dump and a hard opening. Looking at reserve packing instructions, I found the Dolphin manual says 2-3 inch locking stows, the Mirage manual says 2 inches for micro-line and up to 3 inches foe Dacron line, and the Reflex manual says 1 ½ inch locking stows." I believe canopies inflate in 3 "stages" Stage 1- once he canopy is out of the bag, it will "snivel" until the nose catches a bit of air and it begins to pressurize, making the bottom skin slightly larger than the slider. Stage 2- The bottom skin begins to inflate, out-pacing the pressurization of the canopy. The slider slides down the lines Stage 3- Canopy pressurization. I think hard openings are caused by; high speed deployments, Stage 1 initial pressurization being too much/too fast, exposing too much of the bottom skin around the slider, creating a faster stage 2 bottom skin inflation, pressurization catching up to bottom skin inflation which forces the slider down the lines too quickly and causes stage 2 and 3 to happen simultaneously, or not keeping the slider all the way up against the stops. A canopy that has a pocketed slider that takes too long to open can be very easily fixed by making the pocket smaller or removing it. If it is a large pocket I would recommend making it smaller (sewing across it and trimming the excess), if it a small pocket, remove it. Hook Quote Share this post Link to post Share on other sites
freeflyguy 0 #14 December 17, 2002 Whoa! I tend to not agree with some of your swoop methods, but that is a good analysis of canopy deployment. ---------------------------- bzzzz Quote Share this post Link to post Share on other sites
Unutsch 0 #15 December 17, 2002 Quote Call Dan at Atair and talk to him about the canopy. I personally never pushed or did anything with the nose of my Cobalt. Left it hang and it opened much better then when I tried messing with it. that's what i do with my Ace 100 (also Atair, sold as Viper in the states), and now i get allmost every time nice openings, some are real FAST, but not neckbracking... that's what i learned from this forum, i also asked some experienced jumpers here in Slovenia about that, and since no one had anything bad to report, i went on with it, and lived happily ever after! Check out the site of the Fallen Angels FreeflY Organisation: http://www.padliangeli.org Quote Share this post Link to post Share on other sites
roq 0 #16 December 17, 2002 With certainty you have a trim or packing problem in the canopy. When have correct trim and packing the cobalt is the best openning canopy of the World! I have more than 700 jumps with atair Cobalt and Impulse 75, 85 and 120 and never had any hard openning. Normal the CC and H-mod cobalt has still more soft opennings than original cobalt Don't modifies slider or other in your canopy. Ask Dan Preston from Atair about your problem. If you have interest in my packing see attach. roq Quote Share this post Link to post Share on other sites
bwilling 0 #17 December 17, 2002 Very nice analysis of opening sequence Hook! I started jumping back in 1978, and jumped thru about 1983 or so, and don't remember hard openings being such a hot topic back then... oh, canopies varied in deployment speed, sure, but I don't recall people having openings so hard it hurt them (other than my now ex-wife, who used to get some horrific inner thigh bruises from the Starlite she jumped!). But lots has changed since then... canopy fabric and line materials are different, freefall speeds are way up (even for belly flying!), and I wonder if those changes aren't at least in part responsible for the tendency towards hard openings? It's interesting to note that I have a copy of SDU's Basic Body Flight Video, and if you watched the openings that are part of the video (it's old, I think they're all Sabres they're jumping, as PD was a sponsor), the openings range from one that is sweet as candy, to one that looked like it had to hurt! A very night and day difference between the two, but I don't have the experience to really analyze why they vary so much (and not sure if you could slow the video down enough anyway)... QuoteA canopy that has a pocketed slider that takes too long to open can be very easily fixed by making the pocket smaller or removing it. If it is a large pocket I would recommend making it smaller (sewing across it and trimming the excess), if it a small pocket, remove it. Thanks, I'll try having my rigger shrink that lip down in size (it's prolly at least 2 - 2.5 inches right now), and see what that does to my openings). I know everybody thinks the old Sabres are boats, but it's all relative... loaded 1.2ish, it's the smallest , highest performance canopy that I've ever jumped! And other than the too long snive on openingl, I like the thing... "If all you ever do is all you ever did, then all you'll ever get is all you ever got." Quote Share this post Link to post Share on other sites
freeflyz 0 #18 December 17, 2002 two words ICARUS CROSSFIRE!!!!!!!!!!! Quote Share this post Link to post Share on other sites
cobaltdan 0 #19 December 17, 2002 hook, something to consider that most people do not realize is that the first shock you feel when deploying a canopy is at line stretch before your canopy is out of the bag. this shock is caused by the pilot chute, not the canopy. if this defination is acceptable as line dump i have quite alot of proof as to it happening both video and datalogged jumps. as the opening sequence is a series of fast shocks a jumper is usually incorect when recounting what happened in the analysis of a jump. i.e. 10 different pilots, 10 jumps, same single canopy, and you will get 10+ different accounts of how it opened. probably none of which match the recorded datalogged sensor data. the most dramatic recorded instance of the above was 29g's at line stretch and then 6.4g peak once the canopy came out of the bag. improperly sized pilots especially at higer speeds can definately rock you harder than you canopy. sincerely, dan<><> www.extremefly.com sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
Hooknswoop 19 #20 December 17, 2002 Quotesomething to consider that most people do not realize is that the first shock you feel when deploying a canopy is at line stretch before your canopy is out of the bag. this shock is caused by the pilot chute, not the canopy. if this defination is acceptable as line dump i have quite alot of proof as to it happening both video and datalogged jumps. I think the common defination of line dump, is the PC pulling hard/fast enough that the locking stows come un-done before the canopy comes out of the bag. This allows tha canopy to begin inflating before the lines are taut. I think line dump is extremely rare and is blamed for hard openings when it isn't the culprit. Quotethe most dramatic recorded instance of the above was 29g's at line stretch and then 6.4g peak once the canopy came out of the bag. So, you are saying a bag lock can produce 29 G's? Hook Quote Share this post Link to post Share on other sites
cobaltdan 0 #21 December 17, 2002 i am saying that i have video and sensor data logged showing a 29g's at line stretch with canopy completely in the bag. the peak width is 4 miliseconds. then a completely new peak of 6.4 g's when the canopy exits the bag and catches air (6.4 stage 1, droping to 3.5g's stage 2, width 5 seconds). sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
Hooknswoop 19 #22 December 17, 2002 PC size?, Deployment speed? Suspended weight? I find a PC and bag producing 29 G's amazing. I'm guessing this wasn't a live person being subjected to those forces. Hook Quote Share this post Link to post Share on other sites
cobaltdan 0 #23 December 17, 2002 it was a military tandem drop... as i said the most pronounced example. sincerely, danDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
diablopilot 2 #24 December 18, 2002 Quoteit was a military tandem drop... as i said the most pronounced example. So on a drouge? Did it collapse? 4 miliseconds? What was it 1/2 a second after peak? Interesting data. Interpretation is the key. -jp----------------------------------------------- You're not as good as you think you are. Seriously. Quote Share this post Link to post Share on other sites
cobaltdan 0 #25 December 18, 2002 http://www.extremefly.com/aerospace/press/index.html# click on "slow motion with video". it is a little hard to see the data trace in compressed form... force from line stretch droped almost back to base line before increasing again for opening shock.sincerely, dan<><>Daniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
