skydiverek 63 #26 September 29, 2009 QuoteQuoteI have read lots of threads about more elongation/better for heavy jumpers Nylon – 30 to 35 % Polyester (Dacron) – 15 to 20 % Spectra – 5 to 9 % Technora (HMA) – 4.6 % Vectran – 3.3 to 3.7 % Kevlar – 1.0 % Sparky Are we talking stretch or elongation? "Stretch is the elasticity of a line, and the line returns to original length after deployment forces are reduced. Elongation is the more permanent lengthening over time from loads being imposed on the line." Quote Share this post Link to post Share on other sites
mjosparky 4 #27 September 29, 2009 QuoteAre we talking stretch or elongation? "Stretch is the elasticity of a line, and the line returns to original length after deployment forces are reduced. Elongation is the more permanent lengthening over time from loads being imposed on the line." Elongation is the materials ability to stretch measured in percentage of overall length. The term elasticity describes the ability of a fabric to elongate (or stretch) when tension is applied, and to recover its original shape when the tension is released. Think of a rubber band as having elasticity. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
riggerrob 643 #28 September 29, 2009 QuoteQuoteI have read lots of threads about more elongation/better for heavy jumpers Nylon – 30 to 35 % Polyester (Dacron) – 15 to 20 % Spectra – 5 to 9 % Technora (HMA) – 4.6 % Vectran – 3.3 to 3.7 % Kevlar – 1.0 % Sparky ............................................................................................. Thanks for the numbers Sparky, However, I suspect that part of the reason Dacron helps compensate for sloppy pacing ... er ... takes the jerk out of hard openings is that it is significantly bulkier than other modern lines and creates considerably more friction on slider grommets. Quote Share this post Link to post Share on other sites
mjosparky 4 #29 September 30, 2009 Quote creates considerably more friction on slider grommets. And is usally found on big old canopies jumped by old men. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
skydiverek 63 #30 September 30, 2009 I relined my Spectre 190 with Dacron (used to be lined with Microline) - I can definately feel the difference! The slider descends way slower. Love it! Quote Share this post Link to post Share on other sites
likestojump 3 #31 September 30, 2009 Quote Quote creates considerably more friction on slider grommets. And is usally found on big old canopies jumped by old men. Sparky My Spectre 120 has dacron lines. And I would not call it a big old canopy, nor would I call myself and old man. Quote Share this post Link to post Share on other sites
councilman24 37 #32 September 30, 2009 Someone want a spectre to open SLOWER! What do you pull at? 5000'? I'm old for my age. Terry Urban D-8631 FAA DPRE Quote Share this post Link to post Share on other sites
masterrigger1 2 #33 September 30, 2009 Quote Someone want a spectre to open SLOWER! What do you pull at? 5000'? If I had one, I definitely would have something other than Spectra on it! Just look back at the list of fatalities from the "rogue" hard openings in the last 3-4 years. I think there were two last year just at Perris alone IIRC. Cheers, MELSkyworks Parachute Service, LLC www.Skyworksparachuteservice.com Quote Share this post Link to post Share on other sites
mjosparky 4 #34 September 30, 2009 Quote Quote Quote creates considerably more friction on slider grommets. And is usally found on big old canopies jumped by old men. :P] Sparky My Spectre 120 has dacron lines. And I would not call it a big old canopy, nor would I call myself and old man. See the highlighted word? See the at the end of post? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
likestojump 3 #35 September 30, 2009 I was merely supporting your statement. Quote Share this post Link to post Share on other sites
councilman24 37 #36 September 30, 2009 Not that I can find in the reports. I see one unknown, one that a hard opening started a sequence and maybe one other. Hard to tell if they were duplicate. You'd still have to open at 5000'.Don't see enough data to show that it is more prone than any other. It may be, but I just don't see enough data. I'm old for my age. Terry Urban D-8631 FAA DPRE Quote Share this post Link to post Share on other sites
skydiverek 63 #37 September 30, 2009 Quote Someone want a spectre to open SLOWER! What do you pull at? 5000'? Hehe, I pull at 3200 feet. Takes up to 1000 feet to open ! Quote Share this post Link to post Share on other sites
tuffyjensen 0 #38 October 2, 2009 QuoteAny FAA rigger who holds a "back" type rating can also repack "chair" type PEPs. My understanding is that a back or seat rating can pack a chair, since it is kind of a combination of the 2. At least that is what my DPRE told me.Be Safe and Have Fun, in that order! Tuffy Quote Share this post Link to post Share on other sites
riggerrob 643 #39 October 2, 2009 Ah yes! Tee! Hee! Civilians found a way to blur the distinctions between original military patterns. Back in the good old days (before Velcro) there were distinct differences between back and seat type PEPs. Most back type PEPs require the canopy bulk to be distributed the full length of the container and as thin as possible. Seat type PEPs required the canopy to be folded into a cube, similar to chest type containers. There was even a US Navy container (16" X 16" X 3") that could be inter-changed between seat and chest type harnesses. The primary reason the FAA established a separate category for seat packs was because US Navy seat packs required a bewildering array of hand tacks, break cord, etc. (see Poynter's Volume One) depending upon whether or not you installed a life raft between the container and the pilot's backside. Seat packs also required a lot of hard tacks to hold (extra long) risers to the back pad. The invention of Velcro-closed riser covers eliminated 90 percent of hand-tacking on seat packs. In conclusion, there is little difference between packing methods for chest and seat type PEPs, but big differences - in bulk distribution - with back or chair (aka. long back) type PEPs. And we agree that the FARs are a long way out of date. CAUTION! My next opinion will rile American jingoists. It would make far more sense for the FAA to follow CSPA's example with five different types of containers (2-pin sport, 1-pin sport, Pop-Top, chest and pilot emergency parachute) and two types of canopies (round and square). Quote Share this post Link to post Share on other sites
councilman24 37 #40 October 2, 2009 Doesn't jar me. Just let me get my lap rating first. But, is a Reflex a one pin or a PopTop? What is a Racer? two pin or PopTop. PopTop is a trademarked brand name, for a two pin chest. Don't think the trade marked name was ever applied to the Super Swooper Tandem (SST, Racer for the newbies) But I may be wrong. Even you system isn't perfect!I don't think I'd consider a seat rating okay for the 'chair' type PEP's. But since there is probably no one in the world that has a seat without a back that's not an issue. Counting a chair as a seat to get a seat rating is pretty iffy. I'd have to have OK City tell that was okay. I'm old for my age. Terry Urban D-8631 FAA DPRE Quote Share this post Link to post Share on other sites
