cruzlite 0 #1 March 25, 2004 I heard Mfr's are now recomending f-111 be used in kill line pcs. (Reason; catastrophic failure of zp. ie; a rip will not stop running) Anyone heard this? Quote Share this post Link to post Share on other sites
Tonto 1 #2 March 25, 2004 Yes. F-111 type fabric also has lower snach forces which reduces the likelyhood of line dump. tIt's the year of the Pig. Quote Share this post Link to post Share on other sites
seal_S49 0 #3 March 25, 2004 QuoteI heard Mfr's are now recomending f-111 be used in kill line pcs. (Reason; catastrofic failure of zp. ie; a rip will not stop running) Anyone heard this? What? ZP is not made by coating ripstop F-111 with silicone? Then what are all those mysterious gridlines that you see when holding ZP up to a light source? I thought that mfrs were backing away from ZP PCs because the fabric is slippry enough to cause premature extraction from the pouch by higher freeflying airspeeds. I mfr my own pull-out PCs from ZP because I don't need no stinkin' pouch. If there's a reason that this fabric is inferior, I need to know this because it contradicts many, many safe jumps on ZP PCs. S49 Quote Share this post Link to post Share on other sites
seal_S49 0 #4 March 25, 2004 Quote F-111 type fabric also has lower snach forces which reduces the likelyhood of line dump. If I thought I had "too much snatch force," I'd rather use a smaller PC than give up the durability of ZP. Using adequate bands/tube stoes will control line dump. S49 Quote Share this post Link to post Share on other sites
cruzlite 0 #5 March 25, 2004 In reply to; What? ZP is not made by coating ripstop F-111 with silicone? Then what are all those mysterious gridlines that you see when holding ZP up to a light source? -------------------------------- Quote; "If a tear or other type of failure occurs on an “F-111” type canopy, it is likely to be self-contained and landable. With zero-p fabric, damage tends to be catastrophic and makes the canopy unlandable. Also, burn damage is much harder to detect on zero-p. Frequently burn damage just looks like a crease in the fabric, when in fact the tensile strength in the area has been lowered to only a few pounds." Link to above; http://www.performancedesigns.com/faq.htm#11 Location; Education/FAQ/Why PD builds reserves out of f-111 Quote Share this post Link to post Share on other sites
gus 1 #6 March 25, 2004 I've heard of people recommending F-111 pilot chutes because of their better stability but not for any structural reason. ZP is ripstop too isn't it? GusOutpatientsOnline.com Quote Share this post Link to post Share on other sites
seal_S49 0 #7 March 25, 2004 Quote With zero-p fabric, damage tends to be catastrophic and makes the canopy unlandable. Interesting, and informative reference as to why reserves are F-111 const. Maybe I ought to also get rid of my dangerous ZP main canopy along with the ZP main PC. But wait, If the PC has encountered enough stress to blow out, I gotta think that it's probably already done it's job and I'll replace it when I land, like I did when my first F-111 main PC failed. If ZP is good enough for my main canopy, I trust it for my main PC. But hey, that's just me. Call me a skeptic, but I'm gonna wait until I read the incident reports that show a higher rate of blown-out ZP PCs before concluding that these are inferior. S49 Quote Share this post Link to post Share on other sites
cruzlite 0 #8 March 25, 2004 No, this was not intended as a reference as to why reserves are "are f-111 const". It was an example of catastrophic failure of zp... (In reply to your apparent doubts) It would tend to suport the info. in my post. Quote Share this post Link to post Share on other sites
seal_S49 0 #9 March 25, 2004 QuoteNo, this was not a reference as to why reserves are "are f-111 const". Then why is the blurb in your reference entitled "Why does PD not build reserves from zero-p fabric?" (see PD website) Evidently, PD still thinks ZP is good enough to use in the construction of main canopies, and I agree. S49 Quote Share this post Link to post Share on other sites
kaerock 1 #11 March 25, 2004 I think the catastrophic failure bit is a crock of shit. The main difference between the ZP and F111 fabrics is SoarCoat (or Gelvenar). The fabrics themselves should be as equally reliable as I believe they were manufactured the same. I'd venture to say that the ZP is better as the SoarCoat helps protect the fabric even further from weather, abrasion, UV light, etc. One of the primary reasons I've heard of people using F111 pilotchutes is because ZP will tend to wobble a bit during deployment since it must spill air on the sides. The F111 PCs on the other hand, since they are more permeable will tend to let more air pass through, keeping the PC from wobbling since there is less spilage of air. Wobbling can cause the bag to turn or spin, thereby causing line twists. So let's look at it from this point of view: What happens to a cocked ZP pilotchute at +120MPH? The surface area of pc is rather small compared with the kind of load it is trying to decellerate, if you've got a tight pin or locking stows and the pc is unable to extract these things in a swift movement, it will cause it to hang there a bit and wobble. Wobbling can cause the bag to spin, causing line twists. A stabler PC will still extract the pin or lines from the stows, but giving less chance of an unstable d-bag. One, second-hand opinion. -Rory QuoteI heard Mfr's are now recomending f-111 be used in kill line pcs. (Reason; catastrophic failure of zp. ie; a rip will not stop running) Anyone heard this? You be the king and I'll overthrow your government. --KRS-ONE Quote Share this post Link to post Share on other sites
kaerock 1 #12 March 25, 2004 Line dump? What about stowless D-bags? Don't those line dump on every deployment? I see them gaining in popularity. -Rory QuoteYes. F-111 type fabric also has lower snach forces which reduces the likelyhood of line dump. t You be the king and I'll overthrow your government. --KRS-ONE Quote Share this post Link to post Share on other sites
seal_S49 0 #13 March 25, 2004 QuoteI've heard of people using F111 pilotchutes is because ZP will tend to wobble a bit during deployment I vote for that to be the theory-of-the-week. Stowless D-bags can be next week. I nominate you to make 500 jumps with each type of system & log line twists and opening headings. Thanks for sharing, I hadn't heard about the wobble hazzard. S49 Quote Share this post Link to post Share on other sites
rredman 0 #14 March 25, 2004 I hadn't heard that but I was surprised when I ordered a new pilot chute from Strong for my Quasar II and it arrived and was F-111, when I was expecting zero p. Quote Share this post Link to post Share on other sites
seal_S49 0 #15 March 25, 2004 You know, if anybody really cares, they could always contact the mfr. I've had nothing but good experience doing so. These folks are usually very helpful with technical information. I'm having too much fun with this thread to spoil it now. S49 Quote Share this post Link to post Share on other sites
hookitt 1 #16 March 25, 2004 QuoteI think the catastrophic failure bit is a crock of shit My brothers pilot chute blew out and was replaced 3 times in about 50 jumps. the 4th seems to be fine. That said, I usually put way more jumps on a pilot chute than I should. My current one has over 1000 jumps on it and I'm almost ready to replace it. He packs his pull-out the exact same way I do.My grammar sometimes resembles that of magnetic refrigerator poetry... Ghetto Quote Share this post Link to post Share on other sites
seal_S49 0 #17 March 25, 2004 Are either or both of you using ZP or F-111 PCs and what is the conclusion of this experience? Quote Share this post Link to post Share on other sites
PhreeZone 20 #18 March 25, 2004 Talk to BASE jumpers about wobble on the PC's. They started noticing it on slow motion play backs of their jumps and vented Pilot chutes were the resulting solution.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
seal_S49 0 #19 March 25, 2004 QuoteTalk to BASE jumpers about wobble on the PC's. Don't need to, I'll take your word for it. Have the skydiving equipment mfrs adopted this same rational for solo rig main PCs? S49 Quote Share this post Link to post Share on other sites
rigging65 0 #20 March 25, 2004 QuoteI think the catastrophic failure bit is a crock of shit. You are absolutely incorrect. ZP "shatters" when F111 only "tears". I've seen happen many, many times...but I don't think that has anything to do with why some mfgs. recommend F111 (something I disagree with). Ask youself this: Why would you want the object responsible for getting your canopy out into the air to change over time? F111 wears out and becomes more porous with every jump. How can you expect to get continuity if it's always changing?!? The answer? Buy a new one every couple of hundred jumps...at a cost of about $100. Hmmm...am I missing something here. Do the words "planned obsolescence" mean anything to anyone? If you're worried about line dump (something else I think is pretty much crap - I jump a stowless D-bag), then realize that you don't need at 34" ZP pilot chute! It's more efficient, so it doesn't need to be as big...and it'll be the same every time. With that said, it's not a bad idea to replace your risers and P/C every time you reline your canopy (or at, say, about 600 jumps, if you want to wait). They'll actually go longer than this, but it'd be a shame if you went in because you didn't buy new risers every couple of years. All parts wear out and need to be replaced...but buying something that I know is going to wear out 4 times as fast just doesn't make sense to me! "...and once you had tasted flight, you will walk the earth with your eyes turned skyward. For there you have been, and there you long to return..." Quote Share this post Link to post Share on other sites
kaerock 1 #21 March 25, 2004 Okay, let me rephrase, the fact that it can happen is very real, but I disagree that ZP PCs are more likely to blow out than F111 PCs. ;> -Rory QuoteQuoteI think the catastrophic failure bit is a crock of shit My brothers pilot chute blew out and was replaced 3 times in about 50 jumps. the 4th seems to be fine. That said, I usually put way more jumps on a pilot chute than I should. My current one has over 1000 jumps on it and I'm almost ready to replace it. He packs his pull-out the exact same way I do. You be the king and I'll overthrow your government. --KRS-ONE Quote Share this post Link to post Share on other sites
headoverheels 333 #22 March 25, 2004 I got 900 jumps on my F-111 pilot chute, which was maybe 100 too many. If I had lengthed the kill line, which had shrunk until the pilot chute couldn't quite be fully cocked, maybe it would have worked a bit longer, but it was getting pretty porous. I figured it was time, anyway, to replace it, the d-bag, and the lines. I replaced it with an identical Javelin F-111 pilot chute, since I liked the way it almost never had more than 1-2 twists to be unwound when packing. The replacement one is not quite so good in that regard! Quote Share this post Link to post Share on other sites
mjosparky 4 #23 March 25, 2004 QuoteI vote for that to be the theory-of-the-week. Stowless D-bags can be next week. I nominate you to make 500 jumps with each type of system & log line twists and opening headings. I have made over 500 jumps on a bag with just two locking stows, the rest of the lines are stowed in a pouch much like a reserve bag. I have used both ZP and F-111 type PC's. I have found that this type of bag does not affect line twists or heading. There is no such thing as line dump unless the locking stows are dumped. In that case you have bag strip and not line dump. jmo SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
seal_S49 0 #24 March 25, 2004 QuoteI have found that this type of bag does not affect line twists or heading. Now this sound like useful information! Do you mean that this type of bag doesn't cause line twist or off-heading openings, or that it has no affect (either way) on the probability of these? Thanks, S49 Quote Share this post Link to post Share on other sites
mjosparky 4 #25 March 25, 2004 QuoteQuoteI have found that this type of bag does not affect line twists or heading. Now this sound like useful information! Do you mean that this type of bag doesn't cause line twist or off-heading openings, or that it has no affect (either way) on the probability of these? Thanks, S49 I think this type of bag helps prevent line twists and off heading openings. With stows you get bag whip and the stows release and I feel this whip helps contribute to deployment problems. jmo SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
