Avion 0 #26 January 24, 2005 By using the two triangles together with the shape of the lower edge of the rib, their orientation could be determined. Quote Share this post Link to post Share on other sites
sundevil777 102 #27 January 24, 2005 I understand you now.People are sick and tired of being told that ordinary and decent people are fed up in this country with being sick and tired. I’m certainly not, and I’m sick and tired of being told that I am Quote Share this post Link to post Share on other sites
Avion 0 #28 January 24, 2005 Thinking this through, it would be a big job to do with pencil and paper. The risers are also going to introduce some complication by linking to the lines some distance from where risers join together. I wonder, if canopy designers use AutoCAD. I just got a copy Quote Share this post Link to post Share on other sites
mjosparky 4 #29 January 24, 2005 Quote *** -------------------------------------------------------------------------------- Quote -------------------------------------------------------------------------------- Dacron stretches out trim after a while, right? 500-800 jumps. -------------------------------------------------------------------------------- No, it doesn't. Quote Oh but yes it does. We have know that for years.The center cell lines stretches further than the rest along with the brake lines. You can check it on any dacron lined canopy that has 400 or 500 jumps on it for positive verification. MEL I have a few Sharpchuters with over a 1000 jumps on them with dacron lines and are still in trim. The F-111 material goes away before the line trim does. I will usually replace the lower controll lines at about 400 to 500 jumps because of wear. I often wonder how many canopy pilots can really tell the difference in speed with different line sets. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
mattjw916 2 #30 January 24, 2005 Quote There are a lot of people out there who use dacron. Look at most tandem canopy's out there. They are lined with Dacron. Look at the crew canopys. They are lined with DAcron. Just because it is older and a lot of the manufacturers are not using it any more, doesn't mean it is a bad product.. Do you even know why manufacturers are using Vectran and HMA now? These materails don't shrink or stretch like dacron or spectra. With high performance wings, line length and trim is very important. The best opening canopy that I have ever seen and have ever jumped is a spectre 170 with dacron lines. ...yes I was aware of your points, but thanks anyway. I wasn't disparaging the use of Dacron so I really don't understand the defensive tone of your post. If you want to jump/pack sport, i.e. general use, canopies with Dacron lines, that's a personal choice, more power to you. I just thought the idea of an airlocked canopy with a Dacron continuous lineset was fairly humorous... the pack volume would be hiddeous to say the least. I personally can't wait for the x-braced version. edit: for clarityNSCR-2376, SCR-15080 Quote Share this post Link to post Share on other sites
Avion 0 #31 January 24, 2005 Quote I just thought the idea of an airlocked canopy with a Dacron continuous lineset was fairly humorous... the pack volume would be hiddeous to say the least. I personally can't wait for the x-braced version. Actually, I have been thinking about that too. How would you imagine the cross bracing behind the airlocks? I was thinking bi-cell cross bracing just behind the the air lock with a lot of cross vents so the lower portion will get presurized quickly enough BTW I think the cascades make sense for dacron. Additionally, if continuous lines were used with dacron it would cut the open shock damping effect 1/2. Quote Share this post Link to post Share on other sites
Hooknswoop 19 #32 January 24, 2005 Quote I just thought the idea of an airlocked canopy with a Dacron continuous lineset was fairly humorous... the pack volume would be hiddeous to say the least. I personally can't wait for the x-braced version. It's called the Sensei from Big Air Sportz. http://www.bigairsportz.com/ Derek Quote Share this post Link to post Share on other sites
Avion 0 #33 January 24, 2005 They only seem to list info about the Samurai and the Lotus on the site now Quote Share this post Link to post Share on other sites
mattjw916 2 #34 January 24, 2005 I am familiar with the Sensei... but I have never heard anyone mention that it was lined with Dacron, if so that would be a departure from the recent trends wouldn't you say? NSCR-2376, SCR-15080 Quote Share this post Link to post Share on other sites
Hooknswoop 19 #35 January 24, 2005 I misunderstood. I thought you were talking about an airlocked crossbraced canopy Derek Quote Share this post Link to post Share on other sites
Hooknswoop 19 #36 January 24, 2005 Quote They only seem to list info about the Samurai and the Lotus on the site now Ya, just the pic on the home page. Derek Quote Share this post Link to post Share on other sites
mattjw916 2 #37 January 24, 2005 lol, got it... NSCR-2376, SCR-15080 Quote Share this post Link to post Share on other sites
mjosparky 4 #38 January 24, 2005 Quote BTW I think the cascades make sense for dacron. Additionally, if continuous lines were used with dacron it would cut the open shock damping effect 1/2. Why does dacron make more sense for casades than othe line? How would continuous lines made of dacron cut the damping effect by 1/2? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
masterrigger1 2 #39 January 24, 2005 *** I have a few Sharpchuters with over a 1000 jumps on them with dacron lines and are still in trim. The F-111 material goes away before the line trim does. I will usually replace the lower controll lines at about 400 to 500 jumps because of wear. Quote If you have 900 lb. Dacron the stretch is less than the 525 or 600lb dacron. The trim specs on a Sharpchuter is (+ -) 3 inches which is a lot different that the sport canopies of today. Also,I have never seen a dacron lined canopy that did not have differental lines(uneven) after 1000 jumps. I will talk to Red at flight Concepts today and see what he normally sees with the Sharpchuters on his end. The point I was/am trying to make is that dacron stretches after time and is not considered a good line medium for close tolerance canopies. MELSkyworks Parachute Service, LLC www.Skyworksparachuteservice.com Quote Share this post Link to post Share on other sites
nicknitro71 0 #40 January 24, 2005 Given a cascaded full-line spec with a little trigonometry it's possible and fairly easy to get the non-cascaded line spec. I've done the paper work for my Viper 105. When it's time for a reline I'll put continuous HMA with dacron lower brake lines like precisions' canopies. IMO it's the best of two worlds: low drag and high durability.Memento Audere Semper 903 Quote Share this post Link to post Share on other sites
mjosparky 4 #41 January 24, 2005 Quote *** I have a few Sharpchuters with over a 1000 jumps on them with dacron lines and are still in trim. The F-111 material goes away before the line trim does. I will usually replace the lower controll lines at about 400 to 500 jumps because of wear. Quote If you have 900 lb. Dacron the stretch is less than the 525 or 600lb dacron. The trim specs on a Sharpchuter is (+ -) 3 inches which is a lot different that the sport canopies of today. Also,I have never seen a dacron lined canopy that did not have differental lines(uneven) after 1000 jumps. I will talk to Red at flight Concepts today and see what he normally sees with the Sharpchuters on his end. The point I was/am trying to make is that dacron stretches after time and is not considered a good line medium for close tolerance canopies. MEL Mine have 525 dacron and they are within + - 1 inch. Tell Red hi for me. I am the one flying the flag in his para-gear add and on the web page. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
Avion 0 #42 January 24, 2005 Quote Why does dacron make more sense for casades than othe line? How would continuous lines made of dacron cut the damping effect by 1/2? Because, if your using dacron, you probably want the shock damping effect, or maybe just thicker lines for CReW. If you want the most shock absorption, then you want the cascades. The damping effect would be cut in half with continuous lines because of the way springs work. If you have 5 (ten pounds per inch) springs connected to a weight moving at a certain velocity, then stop the free end of the springs, the weight will stretch out the springs a certain distance before stopping and then starting back the way it came. If you have 10 (ten pounds per inch) springs, the same weight will stretch the 10 springs only about half as far as the 5 springs. There is also a time factor involved, calculus is needed to fully describe all that goes on, but simply the more springs(actually, the greater the spring constant) the shorter the time period is from when the springs start to stretch till when they stop stretching. The shorter that time period, the more deceleration force the weight feels. The weight will experience more deceleration forces with the 10 springs, and thus more of the opening shock will be transmitted through continuous lines than cascaded ones. Quote Share this post Link to post Share on other sites
mjosparky 4 #43 January 25, 2005 Quote Quote Why does dacron make more sense for casades than othe line? How would continuous lines made of dacron cut the damping effect by 1/2? Because, if your using dacron, you probably want the shock damping effect, or maybe just thicker lines for CReW. If you want the most shock absorption, then you want the cascades. The damping effect would be cut in half with continuous lines because of the way springs work. If you have 5 (ten pounds per inch) springs connected to a weight moving at a certain velocity, then stop the free end of the springs, the weight will stretch out the springs a certain distance before stopping and then starting back the way it came. If you have 10 (ten pounds per inch) springs, the same weight will stretch the 10 springs only about half as far as the 5 springs. There is also a time factor involved, calculus is needed to fully describe all that goes on, but simply the more springs(actually, the greater the spring constant) the shorter the time period is from when the springs start to stretch till when they stop stretching. The shorter that time period, the more deceleration force the weight feels. The weight will experience more deceleration forces with the 10 springs, and thus more of the opening shock will be transmitted through continuous lines than cascaded ones. Wouldn't cascaded lines act a a progressive wound spring with 10 lines on top and 5 lines on the bottom? Might this also serve to increase the duration? SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
Avion 0 #44 January 25, 2005 Quote Wouldn't cascaded lines act a a progressive wound spring with 10 lines on top and 5 lines on the bottom? Might this also serve to increase the duration? Now were getting to nitty gritty, and this is where it gets complicated. Off the bat, I'm clueless as to the effect the short lines above the cascades have upon the overall damping. Additionally, I doubt Dacron has a linear constant like springs do. I described a very generalized analogy. In order to explore a specific line set, I would need to research the elastic characteristics of the particular lines used, and do some heavy duty math. Suffice to say, that is beyond the limits of my motivation at the moment Quote Share this post Link to post Share on other sites
mjosparky 4 #45 January 25, 2005 Quote Quote Wouldn't cascaded lines act a a progressive wound spring with 10 lines on top and 5 lines on the bottom? Might this also serve to increase the duration? Now were getting to nitty gritty, and this is where it gets complicated. Off the bat, I'm clueless as to the effect the short lines above the cascades have upon the overall damping. Additionally, I doubt Dacron has a linear constant like springs do. I described a very generalized analogy. In order to explore a specific line set, I would need to research the elastic characteristics of the particular lines used, and do some heavy duty math. Suffice to say, that is beyond the limits of my motivation at the moment Ah, come on, inquiring minds what to know. In any case thanks for the information on how the line thing works. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
Avion 0 #46 January 25, 2005 Quote Ah, come on, inquiring minds what to know. In any case thanks for the information on how the line thing works. OK, if I set myself to the task one of these days, I'll be sure to get back to you with the results. I would definately want to share the fruit of that labor BTW I got PMed from another thread with a statement to the effect that the shock absorbing effect of Dacron is less than significant. I wonder what that means. Whether that the effect is less than noticable, or that the effect is less than enough to soften a hard opening that would otherwise slam someone uncouncious or worse into a more bearable one. Quote Share this post Link to post Share on other sites
mjosparky 4 #47 January 25, 2005 Quote Quote Ah, come on, inquiring minds what to know. In any case thanks for the information on how the line thing works. OK, if I set myself to the task one of these days, I'll be sure to get back to you with the results. I would definately want to share the fruit of that labor BTW I got PMed from another thread with a statement to the effect that the shock absorbing effect of Dacron is less than significant. I wonder what that means. Whether that the effect is less than noticable, or that the effect is less than enough to soften a hard opening that would otherwise slam someone uncouncious or worse into a more bearable one. The elongation of Dacron is not as great as nylon but way better than spectra. I have been jumping Dacron on my canopies since 1985 and I think there is a large difference between it and spectra or other no stretch line. If you ever build a line set, it is easy to see when you pre-stretch the line before cutting. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
Avion 0 #48 January 26, 2005 I noticed Nylon is only being used for military rigs now. Any idea why? Quote Share this post Link to post Share on other sites
mjosparky 4 #49 January 26, 2005 Quote I noticed Nylon is only being used for military rigs now. Any idea why? It is more forgiving to both the equipment and the load, ie jumper. SparkyMy idea of a fair fight is clubbing baby seals Quote Share this post Link to post Share on other sites
