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Everything posted by pchapman
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Agreed. But it is tougher with the fatter people, isn't it? Then the hip junctions [edit: on Sigmas] are supposed to be positioned right at the sides, which makes it harder to lift legs, for the very people who are going to have the least strength to weight ratio to begin with...
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Barrel Roll on Trackoff - Skydive Radio Interview
pchapman replied to kkeenan's topic in Safety and Training
An awkward issue indeed. You may not have much time to track much further, or track at a new angle, or take it much lower... but the options are still better than having pulled instead. There is the argument against rolling that maybe someone caught up with you because you wasted some of your track barrel rolling. That's possible, but usually they shouldn't have been on your radial, making it a dangerous situation. And if they were coming up on you, they probably should have stopped short or pulled higher. (It would be awkward in a barrel roll if you glimpse someone behind and above you, but quite likely you don't have enough time in the roll to confirm their forward speed and whether they were about to dump. There may not be a danger, but what one saw then encourages one to take it lower than desirable before pulling. That is a problem with the roll.) Having a good track and making as much distance as possible is indeed nice. -
Barrel Roll on Trackoff - Skydive Radio Interview
pchapman replied to kkeenan's topic in Safety and Training
What kind of jump was it, the one with the collision? My personal view, after seeing a lot of the previous discussions is this: For normal jumps, whether belly or freefly, there is no need for a barrel roll because the dive and trackoff are designed not to require it. This is for normal jumps where you have to be able to trust that everyone else is following the same game plan, and carrying out their responsibilities properly. But when (for whatever reason) you end up in a shit show and can't trust others with your life, then a barrel roll may help in avoiding a midair, a benefit that may outweigh the loss of tracking distance & altitude. I don't know for sure, but I'd think the barrel roll would typically be done towards the end of the track, so it is not like a small error in heading will make a large difference in final position. One does end up spending a little less time looking in the normal direction (e.g., down & forward in bellyfly), in order to briefly scan a wider arc (e.g., above). If you are willing to pull lower than others, that can even mean that no tracking distance is lost. Where others are starting to pull, there's time for a roll, as long as you don't mind going lower. And that's easy these days, given how high people pull. So: I never barrel roll... except in those few instances where I think the situation is dangerous enough for me to think it safer to do so. -
Lock it up. Already in Incidents, already in Safety & Training.
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I almost did something stupid this weekend
pchapman replied to skydived19006's topic in Tandem Skydiving
When it comes to students who might be a problem, it is easy to rationalize taking them up, despite one's misgivings. "The office gave me this student... I'll just do the best I can." or "Well, they chose to take the risk. If this round & flabby person breaks an ankle on landing, well, that's the chance one takes when one is out of shape in this sport." [Yet the student may not know they are taking an additional risk.] Tough calls to make. -
And when it is really quiet, you hear the rumble of people in freefall. All that stuff I do remember as being really cool to hear when I was just starting in the sport.
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As skydivers we can say that tangles aren't a big problem. But they are a problem. We have cutaways due to tension knots. Tandems with members of the public have tension knot mals. Sometimes more when the lines start to get worn. Wasn't there that swooper (Marianne?) who died with tension knots in her reserve (whether or not a damp reserve contributed)? Or isn't there that video of the woman, who was dating her instructor, who spiralled into a parking lot, smashing her face, with a tension knot on her reserve? (Maybe she could have cleared it.) And you can find references to and youtube videos of BASE jump tension knots, where there is no reserve. Even if we want to make fun of someone outside the sport coming up with wild ideas, tension knots (a.k.a. "cords tangling" for the whuffos) are a malfunction mode that we don't have a solution for. Most of us hardly understand the details, because they are hard to study and the rate is low. So I won't laugh at the issue.
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So it sounds like the height of the flare is starting to get worked out. Low wind days are naturally tougher with more forward speed to deal with. But at a light wing loading one should be able to bleed off almost all speed with a good, full flare. So I'm wondering if the flare isn't being finished off fully, or the flare is slow and the canopy slowly runs out of energy that can be converted into a good flare. But a slow flare tends to leave one with vertical speed, and that may not be your issue. A really light wing loading canopy can normally be slowed right down, because it starts out slow, and has a really low stall speed. So it should be easy to flare to a slow speed. The problem can be is that at a really light loading, there's little energy in the flare to get you swung out forwards to get the canopy in the right place for the (very brief) plane out. So the flare has to be really sharp, hard, low, and precise. (Compared to other modern canopies at higher loading.) That's a reason why downsizing from a super light wing loading can help. Girls get that sometimes -- going down a size from a big student canopy actually gets them better landings. A little more energy in the system allows more swing forward, and more time to adjust and finish the flare as desired. Hard to tell though if that would help you or not. With the 210 you should be able to slow down a lot for landing even in low winds (even if the timing is tricky) which isn't what you reported. So you may need to get others to help you see if a) your flare isn't being finished off properly on low wind days (in which case, stay on the 210 and work on fully completing flares) or b) your flare arm movements are good but the canopy is so sluggish that it is hard to get the timing right (in which case a down size might actually help). Edit: Skybytch is right about the legs. Except for high performance slide landings, legs normally contact the ground only when the canopy is fully flared, slowed down as much as possible, and about to start dropping again. Putting legs down early tends to focus the mind on the legs, leading to forgetting to finish the flare with the arms. As soon as the legs start to move, arms are seen doing things they should not be doing!
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I don't want to take away from your post, but add something else that's on topic. Studies have been going on for a long time: Attached is a photo series of a cat being released in a jet trainer, during a zero G maneuver. Found this in a 1957 aerospace medicine journal. During studies of how the inner ear works, the USAF took cats up in two seat jets. They let the cats go in different positions while floating, to see how it affected the cats righting reflex. A bizzare combination -- kittehs and fighter jocks!
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It isn't uncommon for us skydivers to push things a little but unless you really need to jump, give your body a rest. So unless you got invited to some very special skydiving event, or are terminally ill, take a rest! Everyone varies in fitness level, but think about how tough a landing one can take when one is well, compared to how easy it is to keep tweaking and causing pain in an already weak ankle, muscle, or tendon. Giving your legs more time to heal can dramatically increase their capability. And for god's sake learn how to flare. I know, it's easy to say. There are all sorts of possible things to try: Spend a weekend at the DZ watching people land (especially those at similar wing loadings to you). Find someone who can watch & video your landings. Even take along a student radio and get flare assistance from the ground. Get some help. There has to be some identifiable reason or trend to your bad landings. While falling over or thumping in a little can happen, actually hitting hard enough to not be fully healed by the next weekend is really bad. Are you reaching out for the landing? Is it a matter of tripping on landing? Bad perception of distance & speed? Doing a good multistage flare? (which can sort of still apply even at pretty low wing loadings) Are the landings really that bad that you should be feet together and ready to roll every time, just in case? PLF's can absorb some pretty bad landings.
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Yeah one has to be careful with "minor" mals, and more so with tandems. What you can roll out and walk away from on a solo jump, may not work out well with a passenger. (I did see another instructor land a tension knot last year -- the canopy flew straight with a fair bit of opposite brake but the flare sucked and the older student was injured.) You never know, but it seems like MotherGoose made a good call -- he reported to me using only a little brake to countersteer, so the canopy still had energy and flare left.
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With your toggle lockup, MotherGoose, wasn't there the issue that the toggle was inserted directly into the brake eye, or something like that, increasing the force with which the line clamped down on the toggle? (Jim O. thought that might have happened.) That's instead of the proper way with the white loop on the riser going through the brake line eye, and then the toggle tip through the white loop, to hold everything in place. (Unlike normal rigs, but like some early 80s's rigs or certain BASE packs.) With the brake line directly on the toggle, that would make it easier to pull down to where one could gnaw on it, as one wouldn't have to pull the riser down as well. Either way, the toggle was inserted way too deep. Nice job not having to chop twice in a day! @ Southernman: I saw the canopy, a Sigma II 370. The split was right out at the end, on one of the end cells, 2nd chamber in from the stabilizer. Although the canopy chord is smaller out at the tip, the topskin was split all the way, front to back. Thankfully they didn't make the crossports to that end cell all that big!
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Antonija unpleasant? It seems in this thread he was reasonably polite. After a matter of fact first post, in later posts he also pointed out the good things about Klaus's software and service. So one isn't allowed to criticize something at all now, if the person involved is a standup guy? And there are plenty of people out there in the computer world who don't agree with being forced to upgrade to software versions they don't like. Nothing wrong with pointing out that someone's actions are liked 99% of the time, but neither is it wrong to point out the 1% when someone disagrees.
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And Jumpshack has more numbers to confuse the situation: (value 1 = "our numbers", value 2 = "PIA") FALCON 215 520 564 SABRE 190 -- 509 SABRE 190 W/MICRO LINE 416 -- I'm no expert on these things, but I wouldn't be surprised if the Sabre packs up at least as large as the Falcon. One may squeeze out most of the air to get a book value for volume, but that'll be different than trying to do a regular pack job where a Z-P canopy is going to puff up a lot more than a possibly baffed out old F-111 canopy. Do YOU feel the Falcon barely fits? I have a spare rig that's a Vector II V4 size, for a 390-490 main, smaller than your V4.5. Mine fits a dacron Maverick (200) just fine when it comes to packing -- although the loop is fairly long, thus bulging the lower flap out more, which probably makes the bridle protection a little worse than it would normally be, not freefly friendly in either case. The Maverick is quoted as 468 to 500 in volume. So it isn't an issue of packing, rather whether the rig stays safe for the intended purpose. Have a look at how it is on your rig now. Taking a larger canopy might not be as much of an issue, if one say had a bridle cover flap added. Still, I wonder about the puffiness of a Sabre 190.
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Some of us have been hanging around this web site long enough. (I should get out my old Cobalt 75 for a few jumps again.) To stay on topic: A little info on the Mars Science Laboratory mission's parachute development: an overview in a blog http://amyshirateitel.com/2011/06/14/preparing-planetary-parachute/ a conference paper from a couple years ago http://www.planetaryprobe.eu/IPPW7/proceedings/IPPW7%20Proceedings/Papers/Session6B/p491.pdf and the lecture presentation http://www.planetaryprobe.eu/IPPW7/proceedings/IPPW7%20Proceedings/Presentations/Session6B/pr491.pdf It's a big parachute when seen inflated in a NASA wind tunnel.
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Nice to know it is "just" a liability thing. They aren't claiming that jumpers are breaking federal aviation law, or that jumpers are open to suits under tort law for breaking a signed contract, or that therefore they'll never sell you gear again, or whatever. They're just saying that they the manufacturers can't be responsible for stuff that isn't theirs, that they haven't tested. Well, duh. Obvious to anyone in a normal society; but maybe not in the world of lawyers.
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Interesting to hear how different cultures are perceived in different places, even at the simplest and maybe stereotyped level. Here in Canada I thought the perception of Sikhs might be more towards seeing them as having a culture that harbors some fanatical, violent, religious extremists. Although there have been a few attacks within their community over politics (e.g., a Sikh newspaper editor being killed in western Canada by other Sikhs), the main issue in Canada giving the religion a bad image comes from the 1985 Air India bombing. The 747 took off from Canada and its bombing killed 280 Canadians among the 329 aboard. The investigation never was very conclusive when it came to successful prosecutions, and it dragged on over something like 20 years. So for 20 years Canadians heard about Sikhs killing hundreds of Canadians -- even if it was all the same incident. Killers named Singh, heard over and over. I can't say for sure what others think, but I believe the religion can be seen here in Canada as bringing unwanted tension and extremism "from the old country", even if Sikhs in general will be regarded no differently than any other cultural community.
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Have a Speed reserve, but no links... what to use?
pchapman replied to degeneration's topic in Gear and Rigging
Which can be taken as a roundabout way of saying that soft links are OK to use. a) They list no safety or compatibility issues, thus leaving their use up to a rigger to determine reasonable compatibility (in jurisdictions where that is allowed). It is JUST a legal thing, of worry only to the company, not you. b) They don't recommend, but they don't prohibit. Maybe that's taking advantage of ambiguities in the English language. Opinions will certainly vary, whether this interpretation is acceptable, or total crap! I'll email PD and see if they'll release what force their Slinks were certified to. If C23d canopies have forces listed to assist in determining compatibility, it would make sense for numbers to be available for C23d Slinks. That would assist a rigger in determining compatibility. But it isn't entirely clear what to do with matching the force from one canopy and 4 links. (Mind you, we riggers don't really know much about rapide link strengths either, other than that the breaking load should be somewhere above 5 times the Safe Working Load listed, but without understanding the details of the definitions.) It is also interesting that Speeds apparently ship with #5 stainless, as mentioned earlier, as that's larger than the #4 stainless that are generally considered acceptable on reserves. -
... with lots of bright, neon colors?
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Farmer McNasty – Perris Area Balloon Jump
pchapman replied to RMK's topic in General Skydiving Discussions
Well, what can I say, go take it up on a ballooning website and with the FAA. I had a look at the FAA manual on glider flying, and the section on off-landings doesn't address any legal or land owner issues. So no guidance there. One UK guide for glider pilots noted to be careful about payments to farmers, because of unrealistic inflationary pressures -- sometimes commercial balloonists with a bunch of passengers would pay more, giving the farmer a reasonable little cut of the action for being part of the whole commercial process. (In the pool case, you picked MY pool because we're discussing things on the web... you weren't a skydiver who just picked SOMEONE'S pool on the side of town nearest the DZ that you couldn't get back to. Randomness doesn't excuse everything though -- I wouldn't be much happier if you robbed my home randomly, rather than targeting my home due to a grudge.) As I said, it is all a curious situation. I'm not saying that situations that involve emergency or precautionary landings negate the act of trespass. It is still trespass. But I'm arguing such situations may act as a defense against consequences of trespass. Take a glider pilot to court, and you might have a lot tougher time suing him than if a power pilot just decided to land in your field for the heck of it. (I have no idea what might actually happen in trespass cases, civil or criminal, in different countries.) If a balloon takes off in a certain area, it might have a 95% chance of having to land on private property. When is it OK to launch? Below a 50% chance? 5%? Is the act of launching creating a false emergency? Is an emergency landing one which avoids a bigger emergency? (Better for the balloon pilot to set down now than almost run out of fuel. Or, picking a field intentionally is better than an aviator closing their eyes and creating an emergency where they would crash randomly & unintentionally.) And then does it matter what the chance is for a given individual? Can you launch with a 95% probability of landing on private land, if you expect a flight of 50 to 100 miles, so the chance of landing on one particular farmer Bob's place is infinitesimally small? But what if Bob lives a few miles downwind of an airport where they regularly do balloon jumps --with the balloon trying to land soon afterwards -- now the chance of balloons landing on his land in particular goes way up. That might get closer to the situation that started the thread. At least we skydivers have an expectation of trying to land back at the airport. However, with the number of jumps going on, statistically, fields around the airfield are going to get landed on. Aviation sports haven't clearly sorted the whole situation out. Basically we act as if there are certain limits to property ownership, which of course there are, and in this case, it involves people dropping out of the sky occasionally onto private property. While a lot of ideas have been brought up in this thread, we really haven't been able to advance the argument very far. Recently it has pretty much been, "Aviators sometimes land on private property". "It's wrong to do that!" "But that's what happens, and usually there are no consequences." "It's wrong to do that!" "But that's what happens." "It's wrong to do that". And so forth. -
Farmer McNasty – Perris Area Balloon Jump
pchapman replied to RMK's topic in General Skydiving Discussions
It was a choice, just as a skydiver chooses one field over another, or a glider pilot figures it is time to start looking for a landing site in a given area and not another, and so on. (Would we skydivers gain greater protection under the law by closing our eyes and randomly thumping in somewhere?) I don't know the answers, I'm just pointing out the way things have traditionally been done. (... ironically among a community who are arguably some of the worst offenders when it comes to landing on others' property.) I don't think anyone is saying it isn't trespass, just that one side of the argument would be that there should be no penalty attached -- the landowner can't sue if there are no damages, the landowner can't go out guns blazing, there's no charges laid by the government, etc. If there's a civil case who knows but that's where details and precedent come into play -- with the aviator able to claim that they had to come down somewhere, and couldn't reach an airport. Even if there's no penalty, the trespasser has certain obligations. Just as the landowner has certain obligations -- they generally cannot impound or steal equipment belonging to the aviator. Again, I'm no lawyer so can't clarify all the details for everyone. -
Farmer McNasty – Perris Area Balloon Jump
pchapman replied to RMK's topic in General Skydiving Discussions
Obviously the difference in the pool case is intention. Landings by various unpowered aerial fliers are tolerated on some sort of basis of accidental trespass. The nature of their activity means that there's often a very good chance that a trespass will occur... but with no intention of inflicting that on any one particular property owner. So the trespass is "accidental" when it comes to a particular property -- and so there are no legal consequences normally. The trespasser removes themselves & their equipment from the property and pays for any damage. But the trespass is "deliberate" in the sense that somebody's property is likely to get landed on. It is a curious situation. -
Have a Speed reserve, but no links... what to use?
pchapman replied to degeneration's topic in Gear and Rigging
Interesting. Reference: The use of Soft Links on reserve parachutes in Racer Harness/Container Systems 1/19/2009 http://www.jumpshack.com/default.asp?CategoryID=DOWNLOAD&PageID=Soft_Links_Reserves&SortBy=INDEX -
Have a Speed reserve, but no links... what to use?
pchapman replied to degeneration's topic in Gear and Rigging
The thought was interesting, so I looked it up. The Icarus reserve manual assumes metal links, and the reserve comes with them, but says alternatives are OK as long as certified to TSO C23d to at least the opening force listed for the reserve. ("Average peak force" as noted in AS 8015 rev B or whatever is current) Aerodyne lists C23d certification for their reserve soft links for example. For PD Reserve Slinks I don't see the info online but the paper that comes with the slinks mentions C23d certification. So soft links should be fine. The only quibble would be that either way, I don't see any maximum certified load listed for the either of the above-mentioned reserve soft links. While they are designed to be at least as strong as the typical metal links used, and probably won't be certified to C23d unless that were so, technically if you don't have that number on hand, you couldn't assemble them to any C23d canopy because you wouldn't know for sure that the soft links are certified to higher than the reserve forces. But that's not as much in the realm of day to day rigging as an awkward little issue in the way the whole certification system in the industry works.