pchapman

To assist the thread in understanding the bungee stuff, see the attached photo for an example of how recent Wings bags have been built to use bungees. (Their thinking is clearly different than that of the many manufacturers that say to use, or imply the use of, double stowed elastics.)

The Safire 3 hard opening thread has ended up having a lot of discussion about line stows. http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=4884594; So I want to ask, what do manufacturers actually say about how to stow lines? Which ones recommend double wrapping? Which actually discourage single wrapping? Are they talking about the locking stows, or the other stows in general? If anyone wants to contribute info, that's great. Sometimes it is hard to find out what a company thinks, as something might not be in their official manual ... but be in a blog post, video, or whatever. I'll start with the limited info I have on hand: -- PD has an old document on hard openings (hrdopn.pdf) dated 2004, that is still on their web site. It doesn't say how to use elastics but gets into the tension issue: One can argue about the tension issue since many manufacturers have also been producing semi-stowless bags, where the tension may be relatively low. That document is also in their "Main User's Manual", which is just a scan of their 1990's printed manual. -- The current PD manual on "Packing Instructions" says this: Their photo shows a Spectra lined canopy, with double wrap stows for regular and locking stows. Note that it doesn't say "double wrap" -- it says it recommends it if using large rubber bands. I haven't reviewed the video lately. -- PD's FAQ section states things a little more emphatically: What do other companies say?

(For no-one in particular:) The standard chest adapter, the PS70101-1, is often looked down on because the only strength usually listed relative to it is 500 lbs. Unlike leg strap hardware which often is stated as 2500 lbs or something. The numbers are important but a little deceptive on their own. Leg hardware is much heavier, but the numbers above apply to different things. Leg hardware, much of it is proof tested to 2500 lbs and has an ultimate strength of 4000 lbs minimum. And even the chest strap hardware actually has an ultimate strength of 4000 lbs minimum, being subject to the same MIL or PIA specs. At the ultimate strength an item can have bent and deformed but not break. It is toast for reuse, but has held together. (A secondary effect of deforming might be to change the loading pattern on attached webbing, so it is still a bad situation, but the hardware hasn't actually broken apart.) I long wondered what the actual strength of the chest strap adapters was, and had only ever heard that 500 lbs proof load, which is something which must be achieved without damage. So I contacted Bourdon Forge, which makes such stuff. I got an email back from their VP of Engineering, Cas Manczuk, and he confirmed that that PS70101-1 adapter has to meet the same 4000 lb minimum ultimate strength as other adapters do under the original MILSPECS. I think this puts a different light on 20+ years of debate that I've seen about how wimpy and non-load bearing chest strap hardware is. This doesn't say anything about the harness design any particular company uses for their chest strap, or how the harness and stitching is loaded in non-normal ways when doing hybrids or Mr. Bills. But it does make me feel a little bit better about chest hardware compared to the numbers usually seen.

Note that starting to untwist the risers doesn't automatically make one's body start rotating to undo the twist. After you twisted the risers/lines to bring the twisted part down onto the risers -- as you stated -- in this case you were able to REACH ABOVE THE TWISTS. Which made it easy to grab spread out lines to quickly get the torque to spin yourself out of the twists. One can also note the directions used in this technique: Similar to what was mentioned in the first post in the whole thread, the twisting action one takes is a rapid twisting the 'twisting MORE' direction, rather than trying to slowly get some momentum going to untwist one's body in the other direction. Two opposite directions! The fast twisting action here didn't turn the jumper, but 'added' to the twists at the bottom, allowing the twists to in effect move down the lines/risers.

As Deyan figured out, sounds like the Mirage design of the 2000's. Pics attached.

Like other people, my 'safest' (other than a reserve) has also been an F-111 style canopy. A Maverick in my case, a 200 ft sq 7 cell. I use or have used it for demos, CRW, intentional cutaways from other canopies, having fun trashing a canopy in the air, plus a couple intentional low pulls. Good for reliable openings that are quick but not hard. The flare isn't great any more, but I can put up with that.

I'm not really well informed on the matter, but that's a curious and deceptive use of the term "worked with". If I were a cop investigating the mafia and I have contacts I talk with or informants who pass me tips, I hope you wouldn't say that I'm "working with the mafia".

Says the guy with the screen name JamesBond, with a fast looking motorcycle as his icon photo????

I don't think the CSPA attempts to have any jurisdiction over other than civilian personnel parachutes. So if I as a Canadian rigger chose to pack an ultralight recovery parachute, BASE rig, paraglider emergency parachute, rocket recovery chute, aircraft spin chute, or anything similar, I don't think the CSPA can say anything about it, whether I do a good job or a deliberately poor job (with or without a manual). The FAA in the US wouldn't try to control riggers actions relating to such non-TSO items either? (Things are likely different for recovery parachutes on certified aircraft, where aircraft related regulations will apply and if it says only the factory can repack the canopy, that's likely the way it has to be. Even leaving aside specialized requirements like pressure packing and rocket motor overhaul.) At least that's all the way it appears to me.

Your wording wasn't quite clear, so to clarify: In that video, no bungee seems to have been used. A freefly bungee isn't really meant to stop someone falling out if they try, or if they deploy in a piked body position. It can help keep leg straps from sliding up towards the knees, which would create a less secure configuration in case of deployment in a sit etc.

I haven't read up too extensively about the so-called Mercury 13 but did know about them from aviation history. My take: The women were a bunch of wanna-be's with no official sanction or anything, not part of any space program -- who did some medical tests and some of whose leaders did some lobbying. Although their age & experience varied, they tended to be quite good pilots who had or would go on to achieve quite a bit, given the limitations imposed on them. If they had been male with the same experience, they wouldn't have gotten into the space program either. Even in the latter Shuttle or in the ISS era the chances of a someone getting into the space program was exceedingly remote, if they were no more than a well motivated individual with some decently good experience & skills flying smaller aircraft. To get in, you would still better have plenty of military jet experience, or be a very competent PhD researcher in some field. And become one of a very small fraction of those who applied, who got through all the selection process. The Mercury capsules could largely be ground controlled - heck, chimps did suborbital or orbital flights in those capsules. Nevertheless, experiments and maneuvering could be done by the Mercury pilots, and they monitored and were a vital backup in case of systems failures. (Indeed, that's a part of the role of airline pilots these days given all the systems automation.) So the most highly qualified aviators were selected, whether or not some other humans could have been trained to do an adequate job in most circumstances. So while it all is a tale of people trying to achieve more, and achieve things in place of institutional and societal barriers that make no sense to us now, sometimes I think too much is made of the Mercury 13, who were not in any way IN any part the Mercury program. The most qualified aviators were test & fighter pilots and they became astronauts, whether or not others had been given a fair shot at working their way up the ranks to that very select group.

My question, although it is a bit thread-derailing: Huh? Never heard of any rule like that before. Where? Anyplace else do that? This isn't from the Ban Parachuting Altogether folks?? What's even 'approved'? By a committee? On the market X years? Purpose-built for skydiving? So nobody used Suunto's over the years?

Yeah, that's something not talked about a lot. And then there's currency in different areas, both for safety and for performance. One might be current for basic emergency procedures, vs. being current in bigger way head down, vs. current in CRW, vs. current in swooping etc. I tend to feel more current in a general sense if I'm jumping a day every 2 weeks. Not that one necessarily forgets a lot, but just having the repetition allows one to do things more automatically without having to think through them. Back when I did only 10 jumps a year, when a good average jumper might do 100 jumps a year, I joked that that gave me license to be 10 times more dangerous per jump and still have the same per year risk.... (Obviously there's risk to oneself vs. risk to other jumpers as well, depending on type of jump.)

If that's TL;DR, here is a key example from the article about babies getting seriously ill after using a homeopathic teething remedy:

What was the definition of that again? A DZ sactioned through a sporting body associated with the FAI, right? That's what I recall. So a CSPA or USPA or BPA or similar DZ around the world would be OK, but not an independent one. A DZ like that might not care whether you have insurance, if one is OK with taking the risk. (The same sort of clause is in the Canadian CSPA $3M Cdn 3rd party liability insurance -- Go to Lodi, and you're not covered.)

I can't give you a solution to your puzzle, but can comment. If there are errors, it is most likely at the start of the whole thing in freefall, rather than at the end at low speed. If your wrist alti says 2750' after opening, and your AAD and Viso claim just around 3000' for the "opening" in their data, that sounds non unreasonable. Every device calculates "opening" a bit differently but it tends to notice the fast slowdown near the end of the opening sequence. (Example of variation: My Protrack detects openings at different altitudes, relative to what I see on my wrist after opening, depending on whether it is in regular mode or in SLO mode that catches wingsuit and hop and pop openings better.) How data is averaged internally matters too. My Protrack data downloaded to the computer didn't seem to match up well with events in the sky, until I realized that the smoothed curve for vertical speed is the average of the last 6 seconds of raw data. The raw data bounces around 10-20mph every quarter second so needs some smoothing. That delayed averaging results in most events starting to really show up 3 seconds after they actually happened, even if they technically start to show up within the first second. So when doing detailed analysis, I send the data to Excel from L&B's Jumptrack software, and change the averaging to using 3 sec previous and 3 sec after. So again we have a way in which altitude gadgets may differ in ways we are not sure about, and may lag in reporting events. How it all works together in your case, I don't know, but there are different sources for errors.

I didn't analyze your numbers in detail, but I'll note that the burble, even behind one's wrist, can affect altimeters. Hand position can make a difference of some hundreds of feet! My example: One time I was doing a terminal solo jump, and like you watched my wrist alti intently to check opening altitudes and distances. Now I had a mechanical alti, but the principle remains the same. I was ready to pull, left wrist low down infront of me, and yanked out the pilot chute at exactly 2500' on the alti. I changed my body position as I did so, with the alti angled more vertically rather than flat to the earth. Suddenly the alti dropped about 500', as best I could tell on the mechanical alti. Hey, where did my altitude go?! AAD companies mention how the burble (behind one's whole body) can have an effect of about 300', although that's not the exact number Vigil and Cypres use. Maybe a wrist is enough to give the same effect. Between that and a second of time at terminal, that does get into the 500' range. So when I was fully under canopy my alti read 1300', despite thinking I had pulled at a reasonable 2500' (when that was above the US/Canadian minimums), with a canopy with a not too long snivel.

But remember there are also those companies which fall apart between the time you order and the time you're supposed to get your stuff. Skysystems comes to mind, with the C6 Air and screwing other customers in general too. I got a good deal on a custom freefly jumpsuit from one company, ordered in winter, but it didn't show up until the end of the season. By the next season, the company was out of business. I got lucky. Or some long time jumpsuit company starts to fade away because the driving force in the company has health issues, not because of problems managing the company in normal circumstances. Or one time a very well respected rigger got some good contract in his other job that took him away from rigging and left customers in the lurch and mostly out of contact for months, wondering where their line sets were. Stuff happens. Certainly, the biggest companies are more resistant to that sort of thing.

I can understand why you want to know what 'the true definition is'. While I haven't been working in aerospace for a while, I'm not sure there is one strict definition. If you are engineering a satellite, maybe you'll be very particular about MASSES and their inertial effects. If you are certifying a light aircraft and doing flight tests, you'll put the aircraft on sensitive electronic scales to get an accurate WEIGHT. But you don't need the kind of detail where you need to account for the buoyancy of the steel & aluminum, nor account for the slight changes in gravity at different points on the oblate spheroidally shaped earth. Sometimes one needs to think through multiple levels of accuracy, at other times there are real life approximations to reality that are sufficient. For other things one can also have a standardized reference value, vs. a temporary current value. A plane may have a stall speed listed officially as 49 kts.... but that's for maximum allowed gross weight, flaps up, slow deceleration at 1g. The actual stall speed while maneuvering will depend on its weight, G's being pulled, level of ice contamination on the wing, etc. So, don't worrry too much about the differences for plain old skydiving. Anyway, back to turbulence. Brian Germain did mention the idea of putting on a little G to increase the wing loading, and that's fair enough. You'll have a little more speed so the change in angle of attack for a given gust will be less, canopy pressurization will be higher with less distortion, and you'll have a higher angle of attack (which is OK given that collapses tend to be from the front of the canopy having too low an angle of attack, rather than too high an angle). That's all a benefit in turbulence. (Unless you actually do have a collapse, in which case you'd rather be under a slow, low wing loading student or accuracy canopy!) But at the same time, one has to be practical, and not overdo the "adding G load" concept, spiralling down through the pattern....

You can interpret wing loading both ways. The wing loading on an airplane or parachute is normally the weight over whatever is chosen as the representative wing area. If the parachute or airplane is pulling 2g in a turn, then it's wing loading is doubled in that maneuver. Aerodynamically the wing does have to work harder to create that lift, and could stall or break or whatever. The changes in forces on it are real. But one still can talk about "what's the wing loading" for the vehicle in general, and that means under standard 1g conditions. (One could do weight or mass, whatever, we're not at the level of accuracy where we care about the buoyancy effect of the air displaced by the volume of the object.)

We have had a couple cases like that in Canada. For example, Julian Fantino was a former chief of police in Toronto (in the 2000s), and continued being a top cop in other jurisdictions. He was vocally against marijuana for decades, and right into 2015 when he opposed the federal Liberal government's plan to legalize it. “I am completely opposed to the legalization of marijuana.” — Julian Fantino’s Twitter account, Oct. 16, 2015 (from the Toronto Star) In the fall of 2017 he became the executive chair of a marijuana company in the Toronto area. Elsewhere in the country in another case, news reported, "Former head of RCMP drug squad now leads national marijuana business". The guy boasted how much he already knew about the business... fair enough. While anyone can change their mind and evolve their views, it seems particularly rich for a person to hold others back, until they suddenly jump to cash in at a high level on the very thing they used to oppose. I wouldn't put these guys in the true reprehensible scumbag category, but it is still a little slimy.

Good point on the point loading of harness rings - obvious in itself but its practical effect was unclear. Most of us don't have specs on that kind of stuff, beyond "it's good for X proof load". Something for me to consider. (I went back and looked at the RW-1-82 bulletin on weak rings, and even there they used webbing folded to 1" wide to do the 2500lb proof loading of the harness ring.) You were wondering about getting bitch slapped by the B-12 if one has rings to attach a belly mount, on a section of webbing. Ok, that's at possible hazard. Yet I do have a rig from the '70s with extensions for the belly mount attachments, giving a similar geometry. I think the idea is to load you more vertically (if the belly mount is used) by pulling from the shoulders, without having the belly mount sitting just under your chin. A photo is attached. It wasn't TSO'd as it is from Canada. If the belly mount is used, the short riser hidden under the mudflap pops the snaps and rotates up from the Capewell attachment point. So I wonder, were there American rigs built like that too? Anyway, that rig suggests that even if Baumchen's method does have its hazards for your face, a similar configuration also existed on some regular belly mount rigs in the '70s. Thanks.

A few of my ideas: Yeah hip rings seem a little low. Attaching a belly mount to chest rings would make it better, but only some rigs have chest rings. The crude way we used to do it is just put separable D rings over the main lift web. If one really needed to use the belly reserve, the rings could slide up and maybe damage something, but it would save your life. That method didn't technically follow Canadian rules for intentional cutaways, which mention ''properly installed' D-rings, but that's the quick way people would set things up for an intentional. (I'm just mentioning my local rules as one example of how regulations may get in the way or offer good advice.) One can also just cut up an old rig and wear the 2nd harness underneath. If attaching a main, attach it to the new harness rings. One could skip having a container for the belly parachute, but DZO's can frown on that. (eg, exit back to wind holding PC and d-bag to belly, or have buddy direct bag you out the door. Best for high tail airplanes in case of error!) Or one can say use the cut off main container as the starting point to build a belly container to hold the main. Or attach a reserve to the otherwise unused reserve risers on that 2nd harness. If using 2 harnesses, one has to watch out for 2 outs, as 2 canopies pulling in different directions on 2 harnesses could cause injury. (Locally it choked one guy into unconsciousness when doing an intentional 2 out, and he downplaned onto the grass runway. Survived OK but broke things.) Canadian rules about intentional cutaways actually do mention that a 'second reserve must be worn on a single harness', although says nothing about a second MAIN canopy. Add-on rings attached by webbing through your harness 3-ring: Another way to get rings onto a regular harness is is to build little riser like things where there's an L bar at one end, then 6" of webbing, then any harness 3-ring. Without explaining fully, the L bar goes around one's harness webbing above your normal harness ring, the webbing goes through the extra space in the slot in the 3-ring, and then the new harness ring hangs a little down below one's regular 3-rings. Now you have chest high rings to snap a belly reserve to. No sewing needed on the harness, although a rigger with a harness machine is needed to build the devices. Also seen this method used to attach a belly mount to test jump a pilot emergency rig (which won't have 3-rings, but may have a metal link in the same shoulder area of the harness). I've also seen main risers with a 3 ring added to them, so the sewing is on main risers and not one's regular harness. That reduces the independence of the 2 mains and has thus has complicating factors about exactly what order things have to happen. Setting up cutaway handles & methods takes a little work too. You can also set up 2 sets of mini risers side by side in your harness rings, if they are full sized ones. Seems weird but Strong had or has it on their Tridem rig built for 2 mains on the back to do an intentional cutaway. Finally there are the actual harness modifications for extra harness rings, or a webbing loop to attach separable rings. Usually done at the factory when the rig is being built I guess. Seen it on a demo jumper's rig for giant flags or on a CRW rig for a tersh. There have been posters on DZ who have set up just about any of these methods, and I've learned from them and built my own stuff too. "Have fun and don't screw up!"

It's almost cheating, to include tailgate Skyvans. That just makes all sorts of silliness possible...

EDIT: This is a reply to brenthutch's "Trump saves the planet" post which was in Bonfire but somehow his original post disappeared when it got moved to Speakers Corner. Leaving me replying ... to nothing. Whatever, I'll just leave my reply up. Anyway, he mentioned a news article from Germany where Trump's America was lauded for CO2 reductions (in some recently calculated couple years?), something which other places like the European Union didn't achieve. I argue that the achievement was despite Trump, not because of Trump. ================== That 23 million metric tonnes [that the US saved] is a 0.5% reduction. [ie, a small relative amount] And the UK with a much smaller population achieved a savings of 15 million, largely through CO2 pricing as I understand it (reading the original Die Welt article) The US had the biggest per country reduction, but not per capita. Can you tell me what Trump did in particular during his tenure to achieve that reduction?? Enlighten me. The Die Welt article suggests that improvements in the US in recent years were largely due to energy sources that reduced CO2 emissions. First, increased natural gas (eg, through fracking) at the expense of coal. Increasing renewable sources have also contributed. For all I know, Trump may have spearheaded some policies reducing CO2 emissions. But given his distrust of global climate change theories, and support of the coal industry, I figure the headline shoudn't be: "Trump saves..." But should be more like: "Despite Trump's efforts, the US improves ... I see that the Die Welt's headline is now being trumpeted at places like CFACT, which wikipedia says is a "nonprofit organization founded in 1985 that advocates for free-market solutions to environmental issues,but has increasingly turned to climate denial".