nicknitro71 0 #1 July 15, 2002 Yesterday I did a hopnpop from 3000. That resulted in a major line twist, from top to bottom! I was able to kick them off without cutting away. Everybody at my drop zone agreed that the problem was the pilot chute. I jump a Hornet 150 loaded 1.1 and the pilot chute is a 24” collapsible zero po. Should I change my pilot chute? If yes what diameter and material? ThanksMemento Audere Semper 903 Quote Share this post Link to post Share on other sites
PhreeZone 20 #2 July 15, 2002 24 inch ZP should be fine for that size canopy. Most people use 26 ZP or 28-30 f111. The smaller the canopy, the smaller PC you need to a point. Too large of a PC and it can cause hard openings, too small and it might not cause enough drag to lift the bag out of the container. Why were they saying that it was your PC and not something like body position or packing?Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
Staso 0 #3 July 15, 2002 QuoteYesterday I did a hopnpop from 3000. That resulted in a major line twist, from top to bottom! I was able to kick them off without cutting away. Everybody at my drop zone agreed that the problem was the pilot chute. I jump a Hornet 150 loaded 1.1 and the pilot chute is a 24” collapsible zero po. Should I change my pilot chute? If yes what diameter and material? Thanks i think improper body position or packing will contribute more to line twist then the size of pc. stan. -- it's not about defying gravity; it's how hard you can abuse it. speed skydiving it is ... Speed Skydiving Forum Quote Share this post Link to post Share on other sites
thrillseek 0 #4 July 15, 2002 I know there are a lot more experienced skydivers on this site, but i have never heard of a pilot chute causing line twists...unless, of course, it was braided in the lines. Sure sounds like bad body position during deployment to me....maybe even your packjob. With your wingloading and canopy size, a 24" zp pilot chute should be just fine. Quote Share this post Link to post Share on other sites
Jimbo 0 #5 July 15, 2002 QuoteShould I change my pilot chute? If yes what diameter and material? Has this happened to you on most of your jumps on this system? If it hasn't then the problem probably isn't your pilot chute. My guess is that you got out low, a little worried about the altitude (or lack of) and dumped before you were completely stable. What in the world makes these people think that the pilot chute caused these problems? - Jim"Like" - The modern day comma Good bye, my friends. You are missed. Quote Share this post Link to post Share on other sites
nicknitro71 0 #6 July 15, 2002 I had a line twist once before. It was just two line twists, not a biggie. I know that time was due to packing. My lines were not straight during packing and I just went ahead and close the bag. Anyhow, on that jump I had something like 10 or more line twists. All the lines were in a spiral from the slider up. It took a lot of kicking and spreading to untwist. They think that a small pilot chute does not have enough force to properly extract the bag at sub-terminal speeds. This is their rationale and the speed was definitely sub-terminal. Yes I was in a worry to open and most likely I did open too soon. My body position though felt pretty stable. The question is if a bigger, let say 30” chute, would have prevented or alleviated the problem. CoolMemento Audere Semper 903 Quote Share this post Link to post Share on other sites
PhreeZone 20 #7 July 15, 2002 Are you saying the twists were above the slider? If the PC did'nt have enough force to extract it you would have felt your self speeding up after you tossed untill it had enough force to open the container and pull the bag out. A 26 inch will generate about 80 pounds of drag from all reports that I've seen. Smaller ones get less and 30 inch plus can generate over 100 pounds of drag. To simulate this put a 80 pound weight on your PC and run away from it at 80mph. The weight should be enough to open the container, pull the bag out, unstow the lines, pull the canopy out of the dbag.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
cobaltdan 0 #8 July 16, 2002 a 24" zerop kill line pilot is perfect for a 150 hornet. set your pilot on the ground and flick it so that it catches air and drifts to the ground. do that several times if it catches air and falls without any obvious defects, i.e. always spilling air to one side. the twists were definately not caused by your pilot. sincerely, dan atairDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
nicknitro71 0 #9 July 16, 2002 This is a reply I got from Ned Luker at PISA which by the way was very prompt: Hi Nick Yes a 24" Zero P Pilot Chute at sub terminal doesn't have much "snatch" so the deployment gets a little mushy and not much pull or control either. We'd say you should go up to a 32" F-111 / 0-3 CFM Pilot Chute for better results for sub terminal deployment or if that size is too large for your spandex B.O.C. pocket , go slightly smaller than 32.. Actually F-111 / 0-3 CFM is a much more solid stable pilot chute than Zero P. The problem is the Zero P doesn't let any airflow through the fabric with the result that they tend to oscillate like crazy as the air escapes much like an old Round Flat circular. F-111 / 0-3 are very stable and in fact have greater drag due to this fact. Funny but you'd have thought that Zero P makes a more efficient pilot chute but it isn't. Stay in touch and let me know how it works out for you. BLUE SKIES NEDMemento Audere Semper 903 Quote Share this post Link to post Share on other sites
PhreeZone 20 #10 July 16, 2002 For Subterminal onlys that large of a PC is fine, but at terminal..... a 32 inch PC is going to slam you. I jump a 30 and need to ditch it for a smaller to get better openings.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
Merrick 0 #11 July 16, 2002 Hmmm.... I jump a Hornet 170 (loaded 1.33:1) with a 24" ZP pilot-chute... haven't had anything but wonderfully on heading openings. I don't think that's the problem, I'm gonna go with the flock here and say that packing or poor body position was probably the culprit. Quote Share this post Link to post Share on other sites
SkydiveMonkey 0 #12 July 17, 2002 I did a HnP last weekend, and I had line twists for the first time in ages on my Hornet 170 @ 1.2. I don't put it down to my pc at all - it was body position.____________________ Say no to subliminal messages Quote Share this post Link to post Share on other sites
cobaltdan 0 #13 July 19, 2002 i have to completely dissagree with pisa here. the statement that z-p pilots are unstable because air can not pass through them and spills over the lip is bs. prove it to yourself attach a z-p pilot to the back of your pickup and go for a drive.... we did.. on sizes from 18" -28" to record bridal force vs. time when letting go of your pilot. anyway, a 32" is too big, the 24 is not. you will not have a problem with the 24 on hop and pops . sincerely, dan atairDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
TomAiello 26 #14 July 20, 2002 QuoteThe statement that z-p pilots are unstable because air can not pass through them and spills over the lip is bs. prove it to yourself attach a z-p pilot to the back of your pickup and go for a drive.... we did.. on sizes from 18" -28" to record bridal force vs. time when letting go of your pilot. Hey Dan, Can you elaborate on your PC oscillation tests? You results are in total contradiction to tests performed by Consolidated Rigging and Basic Research, both of whom now manufacture apex vented pilot chutes, specifically to combat the oscillation which you did not observe. This oscillation is very well documented on BASE deployments, on delays from 0-terminal. I'm curious as to why your tests didn't reveal it. Could it have something to do with PC size? Bridle length? Maybe deployment method? Anyway, if you could give me any information about your tests, I would really appreciate the data. Thanks,-- Tom Aiello Tom@SnakeRiverBASE.com SnakeRiverBASE.com Quote Share this post Link to post Share on other sites
billvon 2,991 #15 July 21, 2002 >Yesterday I did a hopnpop from 3000. That resulted in a major line >twist . . . Uh, you weren't using a bungee collapsible, were you? Quote Share this post Link to post Share on other sites
billvon 2,991 #16 July 21, 2002 >the statement that z-p pilots are unstable because air can not pass > through them and spills over the lip is bs. prove it to yourself attach > a z-p pilot to the back of your pickup and go for a drive.... I did that, but I used a boom to get the PC into clean air. I used a bunch of PC's, from 28" F111 throwouts to reserve PC's to 50" ZP BASE PC's. They all oscillated to some degree, but the larger ZP's were the worst. (Interestingly, the Reflex RPC/catapult didn't oscillate much at all, perhaps due to its higher mass and assymetry.) Quote Share this post Link to post Share on other sites
thrillseek 0 #17 July 21, 2002 After reading the posts on this, i have to say that i think everyone is getting away from the basics... How many of us has ever had a funky opening that we wanted to blame on our gear?? How many times, upon reflection did we realize that it was due to our own pack jobs or bad body positions?? Come on people!!! Are you guys really trying to suggest that a *circular* pilot chute would be the most likely cause for Nick's line twists?? If i were a betting man, i would say that when he went for the hackey, he shifted to his right, causing the twist...if not, he had a built-in line twist with his packing...the only other possible/likely culprit was a leg strap that wasn't even. Now, i am not a skygod, but i do have 225 skydives where everything has gone wrong, and that one is new to me Quote Share this post Link to post Share on other sites
cobaltdan 0 #18 July 21, 2002 tom, they were not pc oscillation tests, they were tests of force vs time when deploying variuos size pilots. as a result oif doing this test we got the chance to watch pilots in flight. all tested pilots zp or f111 tended to slightly orbit but not oscillate unstably. as far as sub terminal base jumps: huge difference to skydiving: first large f111 pilots are less stable than small z-ps from what i have seen, base pilots are f111 and significantly larger than skydiving pilots. next you will never have such a slow speed deployment in skydiving (remember you are jumping from a moving airplane). if you do happen to be in a very slow moving plane, it will only take you several seconds to get up to terminal, and if you do not have several seconds to get to terminal you have no business deploying your main, that is what your reserve is for. side note: for safety sake all of us drill certain reactions into our brains, i.e. not s-s-s-s = ching-ching. but one that many of us do not think about making an automatic reaction is altitude vs handle: i.e. sh^t i'm low: pull.....but which handle did you pull? if you are below your hard deck : pull reserve. sincerely, dan atairDaniel Preston <><> atairaerodynamics.com (sport) atairaerospace.com (military) Quote Share this post Link to post Share on other sites
TomAiello 26 #19 July 22, 2002 Quotebase pilots are f111 Not a flame! Not a flame! I just wanted to point out that BASE PC's are virtually all ZP, in case anyone reading this isn't familiar with that. There are a lot of misconceptions about BASE gear floating around the skydiving world, and I'm trying to do my part to stop them. Thanks for the info, Dan. I'll do some tow tests this week and see what I can observe personally.-- Tom Aiello Tom@SnakeRiverBASE.com SnakeRiverBASE.com Quote Share this post Link to post Share on other sites
nicknitro71 0 #20 July 22, 2002 Ok guys, calm down! After my incident the first thing everybody agreed at my DZ was my PC being too small. Again it was a 24" Zero Po collapsible plugged to a Hornet 150. The exit altitude was 3000 and I must have pulled at 2200-2300, i.e. sub-terminal. My body position felt OK but then again what I know! Anyhow, all the very experienced jumpers agreed that I should have gotten a bigger PC in the order of 28”. Next thing I did was to write an e-mail to PISA, that by the way manufactures canopies and containers for quite a while now. With all the respect I trust more a canopy manufacture than someone with 200 jumps, although I listen and value everyone's opinion. I included the e-mail reply in my previous post. I understand that everybody has a different view point on things but the guys at PISA manufactured both my canopies and they make a living doing so. I don’t understand why you think they might have an interest saying that F-111 is a better fabric than Zero Po for PCs! Are these South African dudes conspiring against Zero Po? Again I went straight to the people who MADE my parachute to seek advice and I wanted to share with you so we can all learn from it. Yes it could have been body position but then again every malfunction is always body position! If I were jumping a radical heavily loaded elliptical canopy most likely I would have had to cut away. CoolMemento Audere Semper 903 Quote Share this post Link to post Share on other sites
PhreeZone 20 #21 July 22, 2002 > I don’t understand why you think they might have an interest saying that F-111 is a better fabric than Zero Po for PCs! They could be easier/cheaper to make... plus they wear out after about 400-500 jumps so you have to replace them unlike the 2000 jumps or soa ZP PC should be good for. My f111 PC has streched over an inch since it was new. Talk to sunpath.. they REFUSE to make a new PC size or even ZP... that have a one size fits all F111 PC. It works well since they can make 50-100 and it does'nt matter unlike ZP where you have to have the size just right for the canopy... every ZP PC is more custom work they have to do.Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
nicknitro71 0 #22 July 22, 2002 I thought PISA was in the business of making canopies and containers not PCs! CoolMemento Audere Semper 903 Quote Share this post Link to post Share on other sites
PhreeZone 20 #23 July 22, 2002 PC's are made as part of the container. Other people make them too.... but they are originally sold as part of the container system. Not every company has went and done testing to figure out the correct PC size and material. Do a search for posts from BillBooth and read everything he's wrote on PC's...Yesterday is history And tomorrow is a mystery Parachutemanuals.com Quote Share this post Link to post Share on other sites
AndyMan 7 #24 July 22, 2002 QuoteWith all the respect I trust more a canopy manufacture than someone with 200 jumps, although I listen and value everyone's opinion. The guy you just followed up to, and I think disagreed with what Pisa said, is the owner (i think) of Atair USA, the guys making one of the hottest canopies on the block, the Cobalt. That just goes means that there's a whole lot of disagreement between the experts, never mind the novices. It's probably fair to say that while it might have contributed to your problem, it surely wasn't the single cause. If it made such a big difference, surely legitimate experts would be able to agree. _Am__ You put the fun in "funnel" - craichead. Quote Share this post Link to post Share on other sites
nicknitro71 0 #25 July 23, 2002 Again I value all opinions but my canopy is not made by Atair. I think the most appropiate person to talk to is who actually made the canopy but then again I could be wrong. Cool Memento Audere Semper 903 Quote Share this post Link to post Share on other sites
