pchapman

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Everything posted by pchapman

  1. use a little imagination and try: https://www.vidproxy.com/ (Just relaying the URL; I haven't tried the service yet.)
  2. Sucks that health care is expensive as a war. Cut back by one war in the next decade perhaps? Sounds like someone is doing something about better access to health care... but the problem of lowering cost of health care (per unit of care) in the US hasn't been attacked...
  3. I can't say I've met him [Fournier]. Just that his endless tales of woe seemed so incredible that it might be bad planning and not just bad luck, and so some started to question his honesty too. But I don't have any evidence of the latter. Giving him credit, at least he had hardware and was giving it a go, which is better than all the others who joined the highest jump race in the media but disappeared from view with little accomplished or no funding for their dreams.
  4. It was Michael Fournier who had problems year after year. One can't expect these ventures to go off perfectly but Fournier seemed to attract or create bad luck.
  5. I have no idea what the pro's do, but I lark's head a large Tube Stoe on the end to put my thumb though, so that there's some give in the system. Probably still could get thumb injuries though. (This is for swoop cords inside an old baggy suit, not actually camera wings.)
  6. Bill probably would agree that skydivers would learn that there are ways to practice prior to taking the test. A guide would probably have to be written to accompany the new rules, and canopy control coaches would surely be teaching people how to work up to the flight tests. A similar situation is that you don't try to take a driver's license practical test with zero training. You can try, but it would be stupid. Edit: That's a very good point about accelerated landings being required as a survival skill, not as a swoop skill.
  7. Maybe Michael Fournier came to visit, lost his wallet, and in looking for it, yanked out cables when he tripped over them, falling onto a control panel but breaking his fall by mashing the buttons with his hands, before rolling to the side and knocking Baumgartner headfirst into a well. He hates it when that happens.
  8. I certainly see your points and don't know the answers myself. I bet a lot of differences in opinion lie with all the "exceptions" and whether to grant them or not. A bunch of people want no exceptions, while I want a lot of exceptions, some because it won't significantly impact safety, and some for personal choice. Too many exemptions and there would have to be a session with a psychologist before every jump, and supervision by a coach for every landing, to determine if someone still fulfills the criteria to jump a certain canopy. It is quite possible I suppose that we'd both agree that a jumper of a certain number of jumps and weight should probably be flying nothing smaller than a 170 as his regular canopy. It'll serve him well on starting to learn accelerated landings but is relatively forgiving. But then I'd argue for exceptions. Like borrowing a canopy and playing with it for a few jumps, with little long term exposure to risk. Or doing hop and pops or otherwise not mixing it up in the pattern at a busy boogie. Or having a canopy that's OK as long as he is disciplined and knows it isn't the one to learn to swoop on. Or he's already put in time and money in other aviation activities, how much partial credit do you give for that? So then a 150 might really not be particularly dangerous for some people and some circumstances, while a 135 would be acknowledged as high risk but fine to play with a little bit. Clearly it is a minority opinion, at least among those vocal about it here, that wing loading restrictions should only restrict the most dangerous activity, and not be about forcing "good" behavior.
  9. Compared to the chart, which is mostly about jump numbers, I prefer the systems where one can take courses or demonstrate skills to advance. Then it isn't about being held back while having to do millions of jumps. (I realize you said you just made the numbers up for the sake of argument. It is a wee bit on the strict side at the moment, requiring a minimum of 1700 jumps to do what I was allowed to do at 205. AND many of those jumps have to be on progressively more aggessive wing loadings so forget the tandems etc in one's logbook.) The chart does bring up one good concept to be argued: To what degree are you forced to downsize if you want to downsize more? Certainly, if you are going to jump a certain canopy size, it is very very helpful to already have jumped the next size up of the same style of canopy. But the chart requires jumping within a class a whole bunch before moving to the next class. Even if the number isn't 500 within a class, what are we looking at? 200, 100, 50, 20, 10? I'll admit the old school way of doing things was a bit rapid, maybe 2 or 3 jumps within a class before downsizing again.
  10. To help the OP, this is what the petition is about -- the US Hang gliding and Paragliding Association want to ban jumps from paragliders. I don't know the politics and haven't been an USHPA member in years, but it does smack a little of "not our true sport, we don't want to hear about it." Sort of like the antagonism BASE got from skydiving associations for many years. I'm really vague on this, but just like the USPA, I think you don't HAVE to be a member or follow USHPA's rules.... but it is pretty tough in most places to participate in the sport without it. P.S. - it is one of those damn petitions where the online provider asks for a donation after one adds one's name to the list (with or without comments). I believe one can just stop there and one is added to the petition list.
  11. Any links to a report on that accident available? Some of us don't remember it.
  12. One issue in this thread is lack of understanding of what exactly "method specific" is. As DiverMike said, it seems to apply to students only. My casual reading of the SIM (as a non-USPA jumper) suggests that "method specific" indicates those parts of a student jumper's training that differ depending on whether he is learning by AFF or static line, etc. So the term is to be interpreted in a specific USPA SIM sense, not in a general way.
  13. Oh yeah, in History and Trivia, we love all that old time stuff, to learn what it was like back in the day, hear some crazy stories. Seemingly mundane stories can be interesting too, if they highlight how different the jumping or the equipment was back then. Some people here remember those days, and some came along later and know little about it...
  14. I would also get an Re value in the order of a few million. After all, a reference length of a few feet and 120 odd mph is like for many light aircraft wings in flight, and they're known to be flying in that few million Re number range. I'm assuming that one would use the constructed diameter of a parachute as the reference length for the calculation? No other number is easily applicable. As for Reynolds number effects, I know little about it for parachutes. But Hoerner's classic text on Drag showed a graph for the drag of flat plates. Re numbers had a big effect at very low numbers, but from one thousand to approaching 10 million (the highest tested) there was no real change in drag coefficient. I would think other blunt objects would behave similarly, but I couldn't rule out slightly different effects due to porosity or ribbon slot parachutes etc. Edit: Hey, paratekk, thanks!! I have the earlier version downloaded off the web, the 1978 Irvin manual credited to Ewing, Bixby, & Knacke. That's been mentioned a few times on dz. But the newer Knacke Recovery Systems Design manual, I've never seen that online. Edit #2: So Knacke's newer manual, on page 4-4 says has only a brief section on Reynolds number. It says, "A Reynolds number effect on parachutes working in turbulent, separated flow, has not been established." It also references a graph seen on p 5-29, which again is a short section on Re numbers. The graph doesn't show a lot of useful data (and ignore the line with the big jump in it, because that's for a sphere not a parachute). But basically from 100,000 on up past 1,000,000 (how far?) they say essentially no Re number effect. I haven't searched the rest, but if they only devote about 2 pages out of 511 to it, Re effects aren't going to be too important in most normal conditions.
  15. For a straightforward answer: For a million dollars or two, they could probably buy a different plane that is slightly quieter. That's about the best they can do. And for a given size range of aircraft, there are usually only 2 or 3 realistic options on the market at most, so there isn't much choice. Airplane noise is regulated largely on a federal level, so that you don't get different rules in every different city. The noise at a distance tends to be more a function of propeller tip speeds. To change things you'd have to change the whole engine and prop combination. No turbine aircraft has a muffler, and it probably wouldn't make a lot of difference. If the aircraft is a Twin Otter, then that's already a relatively quiet aircraft...
  16. I think it was Nick dG who joked that if Thornton had bounced in front of Nick's own home... the next morning the cops would have been wondering why there was a naked dead guy on the driveway.
  17. Or look at the side connectors on some tandem rigs. Some places add straps to allow popping the quick ejectors more easily. It can be a simple as a cord tied or finger trapped around the lever, on the thin part just ahead of the big U-shaped grip area. Knot the far end of the cord to provide a grip. I've seen closing loop material used, heavy canopy line, even pullup cords, whatever. Not as much leverage as if one cut a slot or something further out towards the end of the lever, but simpler.
  18. I like your idea of allowing for local waivers, so it isn't one single rule for all, in every circumstance. I'm usually against any limits, just to oppose all sorts of limits that I see as inflexible and ridiculously restrictive. Still, it makes a lot of sense for any skydiving organization these days to create some sort of canopy training system. At least let progression be on the basis of training and skill, not just huge jump numbers. Allowing waivers could be useful for someone wanting to try out a canopy for a few jumps, in good conditions, doing hop and pops only, that sort of thing -- even if it isn't what the jumper should be allowed to use for all their jumps. The system could be abused, but so can any system. Some people say that if a canopy isn't safe for a jumper for all their jumps, they should never jump it -- that there's no such thing as safely "trying something out". No way. I may jump a ParaCommander from time to time, but it would be far more dangerous for me to try to use it on every jump. Same would go for a canopy that's a little more demanding than I should jump all the time. Having training and evaluation systems are a way of avoiding hard rules based only on generic jump numbers and zero training. It's like the old idea that to go wingsuiting, wait for 500 jumps because we cross our fingers and hope most jumpers will have smartened up enough by then. But if they actually get training, 200 jumps is an acceptable minimum. While I would agree that for every license there would be some canopy piloting requirements to fulfill, I'm more wary of doing things "the other way around": The idea of requiring a certain license, before being able to jump a certain canopy. Not sure about that. (Then you get into the arguments of why you need to do two night jumps to get a USPA "D", in order to fly a certain canopy.) My tendency is to prefer a system that is in parallel to the license system, not strictly tied to it, if any wing loading restrictions were in any way restrictive. Otherwise it would be like saying that nobody is allowed to do more than a 2 way head down without their D license. We can agree that whether doing more than a 2 way is appropriate depends entirely on someone's training and skill and background, not arbitrary jump numbers. In the end, I tend not to support a "wingloading BSR", if that's the focus, but I'd support a "canopy training BSR".
  19. I'll jump into this "glass half full or half empty" argument. Wind chill does have an effect. I've had frost nip (a mild frostbite) on my nose after winter freefall jumps from full altitude, when I've never had that sort of damage from other outdoor winter activity. Of course it is for exposed skin -- that's what we are worrying about! You might as well say that there in no vacuum in space because you'll be in a spacesuit -- but you're in a spacesuit in the first place because there's a vacuum in space. Yes, windchill can be over hyped or over interpreted. And the older North American scales, until redesigned by Canadian scientists in about 2001, were poorer, missed some important effects, and predicted colder equivalent temperatures in cold windy conditions than we now calculate. And yes it isn't about the final temperature something will reach. A below freezing wind chill won't cause a bottle of water to freeze if the actual temperature is above freezing. But it will extract heat from exposed skin at about the rate one would get at that low temperature (given certain reasonable assumptions), without the wind. The current tables do show that once there is a lot of wind, adding more wind doesn't change the apparent temperature much. I will agree that getting to -100 is a bit tough, even using "just" Fahrenheit. With the current US / Canadian scale, to get -100F equivalent you need to be at belly fly speeds (say, 120mph) at about -40F (=-40 C). Bumping the speed up to 175 mph only moderately affects things, requiring a -34 F day to give -100 equivalent. Pilfy did admit that his initial calculation was a little on the high side, since he was working off only a simple source for calculation. We'd probably agree that for skydiving it is probably better usually to just quote the actual temperatures at altitude and on the ground, to give an impression of what kind of day it was skydiving.
  20. Worked for me. Short url: http://amzn.com/B00794QI88 (Downloaded the Kindle for PC software first.)
  21. If uneven legs is your problem, I think that might turn you into a human pinwheel...
  22. Hmm, it sounds like we might be getting into a discussion of the types of needle tips that one is supposed to use. On the one hand rigging sources say not to use a 'diamond' as used for leather as it cuts the material; on the other hand in non-rigging sources the 'wedge' is claimed to damage leather less because it pushes material aside -- like they say for round tips for nylon -- yet it has also been said in some places that they have a slight cutting point, it isn't to be used on woven fabric. Are Diamond and Wedge different? And what is good for tough leather or plastic may not be good for thinner nylon? So what's the compromise? I've got some ideas but am looking forward to hearing answers!
  23. Sounds OK to me. Of course it is no guarantee that the viewer won't himself screw up, or be able recognize his own mistakes or avoid them. Those are additional levels of perception and ability. But if one isn't great at landings it can help reinforce ideas in one's mind. If you have the right kind of videos, you get to see those one-arm-down "gusts"; the flares not fully completed; stabbing of toggles; the effect of having the chest strap spread to help get one's C of G above one's feet; sticking one foot out to save a landing instead of PLFing, how it is harder to run out a landing even a little if one is dropping down rather than just putting one's feet down like landing gear; etc. ... all the sorts of things you might have heard about but don't automatically come to mind if you weren't already watching a lot of landings.
  24. Oh yeah, it would indeed be a case of trying to ENFORCE the impossible. But it doesn't seem like they ever tried to even COMMUNICATE the issue. Otherwise we should have heard companies say that loading a PD 126 over 151 lbs or a Raven 150 over 153 lbs was ILLEGAL. We've had canopies like that for two decades and they've said nothing. That's evidence that they don't believe it is ILLEGAL in FAA-land. I'll grant you that some companies suck at communicating in general. I can't even find a Raven manual that hasn't been scanned from paper, and no R-Max manual seems to exist online.