MontyPyhton 0 #1 March 14, 2003 I have a question to the riggers out there. I've seen that there are connector links on the market in two different sizes. One type has the strenght of 400 lbs, the other type will brake at 620 lbs. In my opinion there is a very small range of redundancy if you have a hard reserve opening, maybe caused by head down cypresfire or high jumper weight. Lets calculate a little bit: A jumper weights 200 lbs (circa 90 KG). His terminal speed is above 150 mph (circa 240 km/h). And now we say, that the reserve deploys in one second (one second after the Freebag is away). The g-forces will reach a avaraged maximum (added with the vertical gravitation) of 7,84 g's - peaks not counted. That means, that the reserve connectors must be hold an averaged load of 1550 lbs. All connectors together hold 1600-2480 lbs. What is: * If the reserve deploys in unstable body position? * The jumper is heavier? * The terminal speed is higher? * The g's **peaks** at 10-15 g's or more? This type of connector links seems to be the weakest point of the system. We have fast opening and strong reserves today. But what we do to avoid those inadvertently cutaways?? Quote Share this post Link to post Share on other sites
skygod7777 0 #2 March 14, 2003 Quote have a question to the riggers out there. I've seen that there are connector links on the market in two different sizes. One type has the strenght of 400 lbs, the other type will brake at 620 lbs. In my opinion there is a very small range of redundancy if you have a hard reserve opening, maybe caused by head down cypresfire or high jumper weight. Lets calculate a little bit: A jumper weights 200 lbs (circa 90 KG). His terminal speed is above 150 mph (circa 240 km/h). And now we say, that the reserve deploys in one second (one second after the Freebag is away). The g-forces will reach a avaraged maximum (added with the vertical gravitation) of 7,84 g's - peaks not counted. That means, that the reserve connectors must be hold an averaged load of 1550 lbs. All connectors together hold 1600-2480 lbs. What is: * If the reserve deploys in unstable body position? * The jumper is heavier? * The terminal speed is higher? * The g's **peaks** at 10-15 g's or more? This type of connector links seems to be the weakest point of the system. We have fast opening and strong reserves today. But what we do to avoid those inadvertently cutaways?? well, i can't answere you question,because i don't know. but obviously they're working just fine, people have cut aways, and unstable reserve deployments all the time. and i guess it could break, but i've never heard of it on a reserve. now on a main, i've seen it a couple times. later Quote Share this post Link to post Share on other sites
ernokaikkonen 0 #3 March 14, 2003 First of all: Parachute systems aren't planned to withstand head-down deployments, but will probably stand more G's than your body will. That being said: Soft links are stronger than #5 french links, so if this really troubles you, have soft links installed in your reserve. I don't think the smaller(and thus weaker) #3.5 links are used on reserves at all, but I'm not really sure about this one. Quote Share this post Link to post Share on other sites
riggerrob 643 #4 March 14, 2003 Performance Designs offers their reserves with Maillon Rapide #$ stainless steel connector links or Slinks. Most other manufacturers sell reserves on Maillon Rapide #5 or #6 links. While the math may sound scary, I have never heard of a properly installed steel link failing. As for deploying unstable, people do it every day and live. As for deploying head-down .... your body will fail before an harness component and secondly, any time you chose to operate outside the published envelope, you are on your own. Quote Share this post Link to post Share on other sites
ERICCONNELLY 0 #5 March 14, 2003 QuoteI've seen that there are connector links on the market in two different sizes. One type has the strenght of 400 lbs, the other type will brake at 620 lbs. Not a rigger but the rated strength of links used is greatly less than the actual breaking strength. A safety factor is built into the strength rating for rigging components. For example, Component Design factor Nylon fibre rope sling 9 Polyester rope sling 9 Polypropylene rope sling 9 Alloy steel chain sling 4 Wire rope sling 5 Metal mesh sling 5 Synthetic web sling 5 Chain fittings 5 Wire rope sling fittings 5 Other fittings as specified by manufacturer Nonrotating wire rope as specified by manufacturer but not less than 5 Conventional wire rope 5 Exceeding the rated loading eats into the safety factor and is not recommended. French links fall under "chain fittings and have a design factor of 5 (a 400 lb rated link is designed for 2000 lbs) Somebody catch me if this does not apply to TSO equipment Quote Share this post Link to post Share on other sites
