pchapman

Sounds like they don't want to answer except through lawyers in an actual court case! Good luck.

The data panel photo's resolution is too poor to read well. But it looks like there are multiple discrepancies / errors / typos? There's the 220 maximum (vs. 254 in the manual). I would guess the manual is correct because that's been consistent over the years, as has the web site. (I used archive.org to check the website & manual for April 2008, the date of manufacture for that canopy.) And the kg equivalent says 000? Or can't I read that right? And one of the other suggested weight levels don't match either the current manual or the one from April 2008 - the label I think says 149 lbs for Experts, while the 2008 and current manuals both say 169 lb. And the April 2008 website said 159. Of course, those are just recommendations, and not certification limits -- but still it shows some sloppiness in typing numbers in! Shrug. Give PD a call and ask what's the real value. Wonder if they'll have some original TSO paperwork they would actually share, to prove which value is correct for actual certification, 220 or 254. It would be interesting to see what a newer OP-113 says on its data panel... Lawyers like to get picky about all this kind of stuff, even if it is all in the territory of "a heavily loaded reserve and the jumper chose to use either way".

Spare parts availability for Parachute Systems? Someone said spare parts are available from a "ParaCo" in I guess South Africa. This is an image posted recently on one of the facebook rigging sites:

I can only offer this ancient chart, from 2007, from a Vortex dealer back then. (Ranch Pro Shop in NY) It isn't really helpful that the main canopies listed are only out of date canopies from Parachute Systems like the ZP.exe or Hurricane. Something newer must exist... Vortex container sizing.htm

Thanks IJskonijn for the correction. Vigil in the early days did "recommend" yearly pressure checks on the Vigil II's in early manuals but seems to have removed it from the manuals somewhere along the way (for the II, 2+, and Cuatro) as far as I can see in a quick check this morning. So to correct my previous statements: The Vigil does not require any annual pressure comparisons to an altimeter. (Used to, but not for quite some time) (But yeah it sounds like a good idea to do occasionally since it gives a pressure readout) The M2 does require an annual inspection of the entire unit (which logically would be rigger performed) and annual pressure comparison to an altimeter. Technically that inspection also includes checking that the 'altitude lock release' occurs at the appropriate altitude during climb (e.g., 1475 ft) (i.e., center line between the arrows disappears). Which pretty means having the rig in a climbing airplane with someone watching the M2 control unit. Not sure who is doing that regularly! And by altimeter, they mean something like an aviation altimeter with high accuracy. Good luck for the average skydiver being able to figure out how to actually get a reference hPa reading to compare with what the M2 says. The long version of that: There are hPa to mmHg conversions to do here in North America, plus aviation altimeters show the equivalent ISA pressure at sea level and not the current level at airport elevation. But you could set the alti to 29.92 mmHg and get pressure altitude and use an ISA atmosphere chart or formula off the web to convert to actual pressure. (I have seen web sites with Station Pressure for weather stations but then one better be at that weather station, again unless one is great at using ISA tables.) It all gets kind of messy and even as a private pilot I'd have to puzzle through it. Or am I missing some shortcut? Also, in recent years M2 had changed their lifetime from 15 years (their traditional life), to 15.5 years (probably to match Cypres). Just one more thing I noticed. All good with all that? There's always something that changes in manuals....

Yet lets face it, skipping the maintenance - and increasing total lifetime- is what may be saving Cypres. Otherwise, everyone was buying Vigils or M2's. Cypres' 12.5 years and 2 servicings sucked compared to Vigil's 20 years & 1 servicing, or M2's 15 and 0. Cypres' new 15.5 and 0 is competitive, as have been the prices of all 3 models in recent years. 12.5 and 2 servicings made sense when it was the pioneering electronic AAD and everyone was cautious about AAD's, but the market didn't want that king of careful, cautious, expensive approach once there were decent competitors. (And we also had to get past the era in the 2000's & 2010's when everyone was having recalls & service bulletins, Vigil by far the most of all. The real AAD-war era! Cypres was known for its arrogance in denying problems early on; while Vigil had so many service bulletins, they changed their numbering system so you'd forget how many they previously had.) I know there's stuff in Vigil & M2 manuals about mandatory yearly comparisons to aircraft altimeters to confirm accuracy of at least the pressure sensor.... That very few ever talk about.... But what percentage of jumpers actually do those yearly checks? 1%? 5% (Maybe there are some high end full-service rigging shops that'll do it for you? If those exist, good for them.) I still figure Cypres has the edge on quality of algorithms, and that's what I buy, but most rigs out there nowadays in my area have Vigils. Maybe Cypres' are making a come back, I dunno, but I'd expect them to.

Stirring the pot, eh Jerry? Like many sayings, the one about "the simpler, the better" holds true only in some situations. But you know that too, since you know all the tradeoffs that come with things that are engineered. While all the modern add-ons can make rigging more complex, I'm not sure many jumpers would want to keep things simple and ditch AAD's (complex electronics and cutter design!) or even MARDs (despite all their slightly confusing variety and some valid concerns about certain rare situations). Added safety balanced against reliability and of course money. Super strong Navy Conical? Yeah it'll work, but most of us would these days like the tradeoffs that come with complexity. Like ram-air steering since not all DZs are out in big farm fields any more. Or somewhat reduced weight & bulk would be appreciated -- Doesn't have to be quite as bulletproof (or nylon burn proof...) if a diaper keeps opening sequences less messy. And ram-air reserves have kind of proven themselves (even if the spectre of a bag-lock has never been entirely removed). You sure you'd be OK with a terminal Navy Conical opening? We're not all 20 anymore y'know!

Getting aerodynamic principles just right, and explaining them correctly, is quite tricky. There are plenty of ways to explain something that are "sorta kinda right in some circumstances, for the example being given, but not sufficiently correct to really explain most of the possible situations". And this particular discussion has been messed up by one participant not having really good command of the English language. Not his fault, but makes explanations and interpretations even more confusing & sketchy & vague. I'll certainly disagree with Veis on a lot of his aerodynamics. Although I do agree that the Kutta condition or Kutta-Joukowski don't imply that neighbouring air molecules, one going over and one going under an airfoil, need to meet up again at the trailing edge. That just isn't true. So, billvon, I don't think that is a useful part of how to describe lift. I'll wimp out from wading too far into this, as writing a good textbook explanation of lift is hard. But I'd say: 1. Lift comes from pushing air down. [Circulation in other words, if doing Kutta-Joukowski integration around the whole airfoil stuff] Edit: That's simple Newton's laws stuff, or force diagrams. Pushing air down means you have pushed up on the wing. 2. You can do that with a flat plate, the so-called barn door, at some angle of attack, catching the air. No curved airfoil needed. But, it is a very inefficient way to make lift, as there's a ton of drag for the lift being produced. (At the sizes and speeds we are talking about. Things are different at the sizes & speeds of paper airplanes and insects. [Small Reynolds numbers ]) 3. Airfoils happen to be a shape that can make lift, while still being really low drag. Very efficient, that's why we use them. 4. There is some pressure pushing up on the bottom of airfoils if at enough angle of attack. [This gets complex and depends on exact shape & angle] 4. But most of the lift comes from the top: The way air works is that it speeds up and lowers pressure when moving around a gently curved surface. That's where the Bernoulli stuff come into play. That provides most of the lift of an airfoil. 5. But the air can't turn too sudden of a corner. So at too high an angle of attack, the air starts to separate from the surface of the wing and turns into a swirling chaotic mess of waves and vortexes. The airfoil has stalled. Lift starts to decrease* but drag is massively up, so you no longer have an efficient airfoil and your airplane or parachute is probably going to start dropping suddenly (assuming we are talking about roughly horizontal flight), leading to even higher angle of attack and even lousier flying. *[Edit: Duh somehow I said it was still increasing. Which isn't true for a regular airfoil after the stall. What I should have said is that one can have very low aspect ratio aircraft, or aircraft with strakes, or a wingsuit, or something, where there isn't a simple clean stall. Parts of the wing may not be working efficiently, and there's increasing drag, but lift from say vortexes can keep on rising past say 15 degrees to say 40 degrees angle of attack. The concept of "the stall" isn't as clear cut any more.]

Yeah, I don't know all the in's and out's of Kevlar abrasion resistance, in particular how old Kevlar lines got a poor reputation for degrading so quickly. Was it because of Kevlar on Kevlar between lines? Or a lot of flexing with say coarser weave lines? Or the formulation of Kevlar at the time? Certainly Kevlar doesn't tend to get for example the same 'line burns' that spectra or nylon might, being more resistant to heat and that kind of abrasion. (E.g., in Kevlar reinforcement on some kill line bridles.) Kevlar is better in that way.

To humbly expand a bit on Mark's statement: The wear & abrasion (to itself) issue was the big problem that people talked about. It was all a bit before my time, but Kevlar didn't work out on main canopies, while it was used on a few early ram air reserves, where the frequency of packing was less. (As the OP may know, but I'm just giving a bit of history.) It also was used for a while for high strength reinforcements -- Like reinforcement circumferential bands on lightweight National Phantom round reserves, or being used as reinforcement tapes in ram-air reserves, or being used as the reserve closing loop for the then-popular Racer rigs. I guess it was the first 'extra strength' material out there in use! Kevlar is "an HMA", a high modulus aramid, but must be formulated & woven in a different manner than our current HMA lines which last better. (Although clearly they have their wear issues too, if made really skinny...) So Kevlar had a real wear problem. While for the other things Mark mentions, it was more a case of "being ahead of its time" rather than being inherently deficient -- We didn't all have stainless grommets to resist abrasion, and canopy designs & packing techniques weren't ready either. Just like the early days of Microline / Spectra, where there were more problems with instant openings, broken risers, too small sliders, etc. Thus part of the whole problem was the changes in rigging technique & design needed, for the new material. Here's an example from a 1980 [Edit: corrected. Not '85] CSPA rigger's bulletin, where they quote GQ Security (which produced the Unit ram-air canopy, some of which had Kevlar lines) on some of the pitfalls for riggers to watch for:

Of all the copied media out there, I don't think this is very high on the list for tracking down those sharing it. But it does beg the question: (which might be answered in some other Lone Star thread somewhere) Who is behind Parakit Inc., of Georgetown Texas, who copyrighted the Lone Star manual in 1985? Are they still around? Or are relatives still selling the manual or hanging on to it to sell for millions down the road? I'm guessing not. Reference - link from a friend - it's on the Internet Archive! -- https://archive.org/details/lone-star-parachute-assembly-kit-scanned-manual Sure has some good practical detail on building a canopy, even if an old fashioned one.

Here's what I have, data from about 30 years back when I was new to the sport and a bit obsessed with collecting data and understanding the sport. 1. Two pages from I guess the Italian skydiving magazine in 1992 listing the early tandem fatalities in order. (Apparently there was also one on a European Galaxy rig sometime in that era, that isn't in those stats.) First tandem fatality is shown as the one with one snap not done up, TI spent entire jump trying to hook it up, without deploying anything (even the drogue). 2. An html file from UPT listing tandem fatalities and causes in order (but with no dates). From 2008, back when they listed that on their web site. 3. Scribbled pencil notes of mine from the early 1990s, where I listed a bit of the evolution of tandems (eg the date when Strong & Booth got their FAA exemptions to allow tandems), plus all the early fatalities and dates. I think most of the data on dates comes from an article in Parachutist,July 1989. (Which I can't find at the moment.) That list puts that first tandem fatality -- with the snap not done up -- as Oct 19, 1986. Back in those days people were wondering what the heck was going on with Vector tandems, as in the first dozen fatal accidents, there were 10 on Vectors, and 1 on a Galaxy, before there was 1 was a Strong Dual Hawk. There sure were a lot of different causes of accidents -- Stupid stuff we're not allowed to do with tandems now, main bags that much more easily came out of the container early, plus a lot more casual training and attitudes towards tandems. Which brought in the idea that 'it isn't just another skydive'. It also took a while to come up with the first tandem CYPRES, and eventually the idea of making one mandatory for tandems. (Wish I had the dates for those.) RWS tandem fatality list as of Feb08.htm

I had a look at the manuals to familiarize myself with them. Basically in line with what Jerry is saying, - the earlier Peregrine Glide has a semi-exposed RPC - the newer Peregrine Falkyn had a covered RPC

Here's all mine. (Did you get yourself a 'dactyl?) Paradactyl Manual (slightly expanded version).pdf Paradactyl - shorter Guardian manual [P Chapman scan from M Stevens copy].pdf Paradactyl manual (DactylManual)[M Stevens scan].pdf

A tip -- If you can turn off Javascript and refresh, most WaPo articles can be viewed. (Depending on the browser & operating system, that can be very longwinded to do, or easy to do with some browser extension.)

From BasicOne's posts, I get the idea that the M2 cutters are like this: a) The old ones had the "flat plate plunger" design that shears the loop at both cutter holes. Something not at all known to the public before, I think. Quite a different design. b) Then I guess after Airtec/CYPRES' patent expired on single blade cutters, newer cutters use a single blade like a Cypres. That the kind BasicOne did tests on, using 2019+ M2 cutters, and was concerned with the amount of damage to the cutting edge after firing.

Boy this brings back memories of the AAD wars from a decade or more ago! As far as I recall, this is how I'd put this into context compared to the other AAD companies: Cypres always had the hardest, best cutting cutters. Vigil has the circular cutters (effectively 2 blades), that they tout as being a good concept, but have come under some criticism, even though they generally do the job. (eg, one serious critique in "What's going on with AAD's" by Kirk Smith, 2011) Argus had serious cutter issues. They also used circular cutters. (I got the impression that was due more to a Cypres patent in the early days?) Most issues were actually with their older style cutters, before upgrades in hardness & manufacture, but in any case the tide turned against the company and their AAD's are pretty much irrelevant now. Mars M2.... don't recall hearing of cutter issues before (for actual cutting), but never saw any engineering data on their cutter hardness. (There was one accident relating to their very old MPAAD design, not the M2.) Someone should ask Mars about their M2 cutter hardness. That's just one measure of goodness, but a decent one. I would still have to dig up info on other designs, to see what metal hardness values were found for other companies. .......Hmm, here's something I had on the Argus vs. others: (My interpretations of the Polish report on the fatality there in 2009 that involved the Argus.) So, I wonder what an M2 cutter is like. Great testing by the original poster, BasicOne, thanks, but I'd like to see independent confirmation too! [Edit:] After all, the M2 has been reasonably popular in recent years too, and surely cutting loops successfully, even if not out there in number like Vigils and Cypres'.

Sorry, can't be true. I don't know anything about what may have gone on in the background, but the canopies are very different. Excalibur wasn't tapered -- Adding taper was a huge change in canopy design complexity! Excalibur had different nose inlet shapes. Different standard sizes. The Precision built FX's were of course licenced from Icarus in NZ. Maybe that's what you were thinking of? (I still fly an FX but don't know all the history from back then!)

Space X uses Pioneer drogue parachutes for the return of their Dragon spacecraft. (But Airborne Systems provides their main parachutes.) High speed parachute design is a specialized thing, so even Space X didn't do it in house. Still got my Pioneer Titan canopy, though it has been a decade since I used it at Bridge Day... Will be interesting to see what happens to Strong.

Interesting. How much of an issue is this in practice? I don't know, but I see the EG18X smoke grenade is on the list as no longer exempted. Its baby brother -- with less smoke volume -- is the EG18, isn't mentioned, so that one is still OK without the extra regulations. I have used the EG18X on demos. A pretty decent grenade for that use, at a reasonable price. Some years back they seemed to be the best I would see available. But in recent years there are pricier grenades out there with higher performance. So I don't know what high end, well sponsored teams use. But for smaller demos, the EG18X's were nice to have. So it kind of looks like the higher end, better stuff, is getting more regulation.

Since this 2018 thread was revived: It is interesting to consider the "two ways to double stow" issue that sundevil777 brought up after Westerly's observations. To recap, there's the "wrap around twice like wrapping it with tape" , and there's "make a single stow, stretch the elastic, make a half twist to create a new 2nd loop, and put that over the line bight". One sees the first method, for example, in one PD tips youtube video. I confirmed that both methods are equivalent topologically in the sense that the final result can be changed from one to the other while the elastic is in place on the lines. If you try it, you can look down at the line bight in its double stow, and move one loop of the elastic over a little and be back to the first instead of the 2nd configuration. Like sundevil said, there's technically no actual knot created. But the 'twist 180' method does seem a more secure or little more grabby, as there's more rubber band overlapping other parts of the rubber band. Whether there's any significant effect on line deployment in practice, who knows. So far I'm not worried about which method I use. I also tend to do the twist 180 method. Which one does will depend on what one is used to , but perhaps also likely on how tight the elastics are when trying to wrap the bights. The simple wrapping method works better for me if there's a lot of stretch in the elastic relative to the position of the lines needing to be stowed. As for Westerly's elastic breakage issue: I may not be imagining correctly what Westerly did. I'm not sure if he meant putting in the 180 twist, or even adding another 180 on top of that, which does change things and make it impossible to simply slide the elastics around once in place on the line bight, to change to the other configurations. That might in effect be 'tighter' and put more stress on the elastic when the bight gets yanked out of it.

Lines out of trim. (If they are the kind that go out of trim. Any Spectra in there,as main lines or brake lines?)

Still F-111 if I recall correctly. An invention a little ahead of its time, just waiting for ZP to arrive...

Paragear 1991-1992 catalogue, the first with the Cypres in it: Cybernetic Parachute Release System (Cypres) $1225 (In current dollars, that's $2770) (Compare to Cypres 2 price at Paragear now, over 30 years later: $1199, less than the original dollar price, with a longer life and no mandatory servicing either.) Also in Paragear that year: FXC AAD $695 (A lot less than the Cypres, but its 2 year factory checks added up too, for the diligent DZ's that did them.) RWS Vector II $978 (Cheaper than the Cypres) (In current dollars that's $2210.) (Vector III at Paragear now is $3350, over 50% more despite accounting for inflation, although it certainly does have a few more features than a Vector II. Still just certified as a Wonderhog.) [Edit: Inflation calculated online with 1991 average, to Sept 2023, the most current data, for the US CPI]

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