erdnarob 1 #51 July 7, 2008 Thanks. Brian Germain's advice should be read by every jumper. Good stuff. As Brian says, it's difficult to get all aspects into one formula. Little discrepencies have to be allowed depending on each case. But I see another factor, the trim angle which is very shalow on a Nitron (13.75 degrees) versus a very steep one on a Katana (18 degrees) and the Samourai (17.35 degrees). Angle calculated according my own method: 1) taking the middle cell lines left or right, 2) measure the distance between A and D attachment points = X, 3) with the same attachment points on tension measure the difference of length between the A and D lines = Y, 4) angle = arcsine (Y/X) which is a good approximation. Any comments on that ?Learn from others mistakes, you will never live long enough to make them all. Quote Share this post Link to post Share on other sites
Chrisky 0 #52 July 7, 2008 Well, your question can not be answered by anyone here in a simple short post. Elliptical wings tend to be much mire agile than square or tapered ones. Thus, they usually have very different turn rates and subsequently very different dive characteristics. An entry-level canopy by general consensus is a docile canopy with a linear turn rate (the turn doesnt "sharpen" given constant input), so entry-level elliptical is an oxymoron. If you want to know more about the effects of a canopies' planform (rectangular, tapered, elliptical etc.) and the characteristics of the different shapes, I can't recommend Brian Germains book "The Parachute and its Pilot" highly enough. It covers both the aerodynamical/physical as well as psychological/physiological aspects of a canopy in flight in easy to understand words. You can order it from the bigairsportz web site. Best money i ever spent on a skydiving book, made me a better and more aware canopy pilot.The mind is like a parachute - it only works once it's open. From the edge you just see more. ... Not every Swooper hooks & not every Hooker swoops ... Quote Share this post Link to post Share on other sites
billvon 2,395 #53 July 8, 2008 >how many jumps should have an aware and proficient jumper at >landing with a rectangular canopy in order to jump a Nitron 190 after a >good briefing (loaded at say 1.2) ? It would depend on the size of canopy they were jumping at the time, their number of jumps, their education and their weight. (1.2 at 100 lbs is nothing like 1.2 at 200 lbs.) Let's take an example. Jumper on a 1.2 Sabre 1 190; jumper weighs 190 lbs. He has 200 jumps and has been jumping the Sabre 1 for a few jumps now. He stands up 3/4 of his landings. He is not ready to downsize or go elliptical. Same jumper on a 1.2 Sabre 1 190. He has 250 jumps and has been jumping the Sabre 1 for the last 50 jumps. He stands up 99% of his landings, and can flat turn, flare turn and land downwind and crosswind. He might be ready to go to the Nitron 190. Same jumper on a 1.2 Sabre 1 190. He has 300 jumps and has been jumping the Sabre 1 for the last 100 jumps. He stands up 80% of his landings, but sometimes a "side gust" knocks him over when he tries to land. He has been told over and over "NEVER TURN LOW!" so he has never tried to flare turn or flat turn below 100 feet. He jumps near the coast and always lands into the reliably-steady west wind. He is not ready to downsize or go elliptical. Quote Share this post Link to post Share on other sites