pchapman

Although to be picky -- like you :-) -- it will depend on the angle of the pull on the thread. If the looseness in the thread combined with the width of the lanyard means the thread is pulling back 180 deg opposite to the lanyard, then 8 lbs works. But if the thread is more taut, with the force diagram more of a "Y", then the end loads on the thread have to rise faster to oppose the pull, and the thread will break at less than 2 times its actual strength. With various real life variables and geometry, who knows what the actual force will be. Haven't tried measuring it. Still just a small number of pounds.

This is about the Vigil video that was put up (not the Cypres that started the thread): Although there could be angle of attack changes, the jumper is still belly to the wind. So I'd prefer to say: As he slowed down quickly (in what wasn't a high end swoop) the burble quickly reduced. Same result. Pop.

Thanks for saying that. As a rigger I've seen a couple examples in recent years where a customer had big problems with Mirage. Nice rig though, and they do want to stay current -- eg, with their innovative MARD solution. Although someone off the original topic, I'm also concerned about Mirage's performance. Skydiving is a small industry so I don't want to be too tough... but still want to hold companies accountable. In 2016 I had a rigging customer with a Mirage rig, who needed spare parts after a cutaway, and was looking to buy a new Mirage too. After the hassles he had, he went to another company. He tried to buy a split main bag like they used to have. Mirage doesn't normally now make them that way, but agreed to make him one. When it arrived, the alignment of grommets and center stow (that goes through a grommet to pull the split together) was all wrong. It was like a junior rigger's error -- looked nice at first but showed a complete lack of understanding of how to build a split bag. Some corporate memory had been lost. He bought a new Mirage main pilot chute through a dealer website. It arrived with the reinforcement sewn along the lines of the mesh, instead of along the 45 degree bias. An email to Mirage bounced; a web form submission got no reply; only after posting on dropzone.com did someone from Mirage get back to me, saying they had been having website problems. They did confirm the pilot chute was built the wrong way and would be willing to replace it if the customer sent it back. In another thread in the last couple years, someone showed pics of main toggles that had a particular easy-open design that he liked. Mirage denied that they were from Mirage, but I pointed out that they were the very same design Mirage showed off proudly in 2002 when they improved their velcroless toggles. Again, corporate memory seems to have been lost. From other posts I've seen on dz in recent years, when I started looking whether anyone else had had problems:

Cool, the fun things one can do with some used gear and a big pull testing machine! As a rigger I have almost no stuff like this saved on my computer except the Wilcox webbing tests published many years back. My thoughts: (After looking thru all the pics, trying to do a reasonable job of analysis, but without very careful comparison. Anyone feel free to do a better job of it.) Doing a bunch of tests on different risers really showed how much variation there is. One could still see trends, like mini risers with 'normal wear and scuffing' breaking at 3300lb and more. While heavier worn ones with actual broken strand fluff near where webbing loops around rings, breaking down to 2500lb. The damage in those cases didn't always look that terrible but decreased strength a fair bit -- Reminds me of what one gets with edge damage on lift or leg webbing. (Of course there's a lot of subjectivity about what minor vs. heavy wear is, when many of us don't have a feel for what actual strength losses occur.) It can still be debated, what the effect is on use in the field, if a riser's strength decreases to 2500 lb compared to an original 3400 lb or so. Risers in the tests didn't always break at the point of most noticeable wear, with no really clear patterns seen at first glance. Still, modern risers (at least as VSE builds 'em) don't break at the grommet hole (only saw that once in the dozen odd tests), but typically in the webbing by the small ring or the big ring or some combination. (I didn't try to analyze the exact sequences carefully.) The type 2A loops, even when somewhat worn a little, weren't breaking, which is nice. That loop, while still rather important, is one that easily gets some wear relative to its small size. As for leg straps and MLW's etc.: Edge cuts are nasty as we've been told. (eg Ty 8 lateral failed at ~1800 lbs vs. 4000 spec) Fuzzing at the edges, while one does see quite a bit in the field at times, can have a big effect. (Some edge fuzzed type 7 leg straps failed at slightly under 50% of their rated strength.) I'm not sure we always like to admit that out in the field. Strong acid kills nylon, as we know. Thanks to VSE for being willing to show off their stuff, all worn and ripped up!

That works? You've tried it? Even with Cypres' "need to fly above 1500' to enable"? Or does a bit of suction first fool it? I used to do the bag trick for FXC's, and a rigger friend set a relatively unsophisticated Vigil II off, when storing a customer rig in a big bag and squeezing air out of it. Oops. (But 2+ models have a minimum alt to climb past, like the Cypres.)

Yeah, the bigger the fan or rotor the more efficient. Any backpack or bike style one may work, but be pretty limited in range and weight. Even super light personal helicopters with the efficiency of a big rotor are pretty limited in their carrying capacity. Now this turbine bike thing seems to come from a company with traditional hydrogen peroxide jetpack experience. On their webpage they show that one of their guys crossed the Royal Gorge with one, with no backup parachute or anything. That's fine for a demo as long as they feel confident about the reliability. (Which could actually be good for a well designed hydrogen peroxide thing with few moving parts) The jet bike video shows the guy staying fairly low over water usually, although an engine failure in this widely separated 2 engine thing would be much worse than in a 1 engine device. Just plain falling is likely a lot safer than the gyrations of losing one of 2 engines. The best one could do is have the electronics switch off both engines if a solid state gyro indicates too great a bank or roll. The next step would be to add in a ballistically deployed canopy, also electronically fired. Not much help at 50' perhaps over hard ground, but could be useful if 300' up. Anyway, cool toy they made, presumably aided by electronics (like solid state MEMS gyros) to make these sorts of things far more stable and controllable than the stuff tried in the 50s and 60s. Maybe those model airplane style turbines (I presume) are pretty reliable, and one wouldn't be putting many hours on them anyway when doing demos. Beyond demos in front of a crowd though, I don't see much use for the turbine jet bike.

I suppose it is a perfectly usable reserve, John. But, I question whether Strong really wants to sell any? On their web site they hardly market it: They don't show a manual (as far as I could find). They don't list the TSO version. They don't list max certified weights, only maximum suspended weight values that correspond to a 1.2 max wing loading -- in other words "Oh, that's like a old 1980's reserve design, not to be loaded up like a modern reserve designed in the last 25 years."

Nobody generally measures these things, or at least there's nobody outside of manufacturers measuring and publishing this stuff. It's not like the paragliding world where one might see a flight test that lists the minimum sink at trim speed at a particular wing loading. I notice you mention some PD products in there. You can go to their web site and see documents comparing flight characteristics of their products, which can help in understanding how their canopies differ (eg in glide angle and descent rate).

Aw man, guess I hadn't been keeping up on current events. It ain't fair, man! I did go right back and review all his great lines in Aliens, many of which are in the IMDB quotes for the movie.

Using the backpad mounted closing loop as a replacement for the top flap is simplistic but workable and clever. Saves building a flap. But that lack of pin protection is a bit sketchy as RiggerLee said. It might be ok in a half full Twin Otter but scarier in a C-182. One would also need to be on good terms with the DZO to not get into trouble! (The more one has the trust of the DZO the sketchier the stuff they'll let you take on their expensive airplanes...) The sharp turn of the cutaway cable when attaching the handle to the chest strap: Easy to improve if you want - If the cutaway housings are tacked at their end, untack them there from the webbing, slide them out of the webbing loop they are in, and tack them higher up. Then one has a few inches one can bend gradually instead of making the cutaway cable do a sudden 90 degree turn. Attached: extract from a selfie some years back, showing that feature along with the big cutaway handle I built.

Well, the video shows what the media (or much of it?) obscured with their statements. While he literally "flew over the airliner", it was not there when he started his approach. The airliner moved forward and under his approach, while he was on fairly short final. So while he still screwed up, it changes any implication that he started an approach staring at an airliner directly under his flight path.

May I ask, how do you get around the Airtec cutter patent? But it has been a while so is it still in force? I haven't tried to read up on the issue but as skydivers we always were used to the Airtec single blade while 'everyone else ended up using a circular cutter'.

For everyone comparing cutters, we clearly need to whip out the M2's flat sided cutter as well. A pic from the web is attached. (From a review of the M2 at skydivenow.co.uk )

Huh, big yellow on black letters saying TAXIWAY, on the taxiway!

FWIW, here's a capture from Google Earth on approach to 20L or the taxiway to the left of it. I haven't tried to set any particular approach angle or anything; just eyeballed it. In this screenshot, the runway markings relative to the taxiway are somewhat clear, although less so if one takes a view from further away. Still, 20L is definitely more prominent than the taxiway to the left of it. (I believe this is taxiway C that he landed on but haven't checked the web more.) People do screw up at times, including getting fixated on stuff. Maybe he was overly focused on staying to the left, left, left. We just don't have much information to go on so far. And I think avoiding the airliner was no big deal considering he was in a light & responsive aircraft. "Hmm, why is the airliner there.... seems an odd hold point... well I'll just land a bit long.... focus on the landing and sort it out later."

But all we ever got was a radioactive Russian satellite crashing on our country! (Ref: Kosmos 954)

Someone must have researched this stuff but what you say seems to be a factor. When someone has to balance near the edge of something, the yawning chasm and lack of normal ground reference points nearby seems to make vertigo more likely. But when we are supported "securely" in a parachute or paragliding harness, there tends not to be such a fear of heights. That seems to work whether the ground is 10,000' away or 300'. It isn't as if tandem or solo students get antsy close to the ground. (Other than really close, when the increased sense of motion can be offputting -- but that's more about speed & feelings of control & potentially crashing into things rather than traditional vertigo.) The point made earlier by others about jumping from a plane for AFF vs. static line may still hold -- the remoteness of any ground references may indeed make the AFF jump less scary. That is a sort of 'fear of falling' thing but I'm not sure it qualifies as classic vertigo though. I would want to test someone who is scared of heights near the edge of a cliff or high building, and restrain them in a securely fixed easy chair or hanging harness. Maybe that would remove the vertigo aspect, the feeling of not being balanced at the edge of something, as there is no need to balance. Some other part of general fear of heights might still exist though, but the overall level of discomfort should go down. Anyway, I kind of think there are different aspects to the fear of heights and it is interesting to figure out where the causes lie.

My dad dealt with all sorts of tube technology, so I'll pass that klystron related 1957 advert on to him! Canada did end up with a lot of radar chains on its soil, largely US funded, to provide advance warning of the Russkies. There was the Pine Tree line, Mid-Canada Line, and DEW line. Although I'm oversimplifying history, each was kind of obsolete by the time it was finished and the next one further north was built at great expense

The performance of pilot chutes has come up from time to time here. I came across this link - Some pilot pilot chute testing in a horizontal tunnel in Oshawa, Ontario by Matt G, Will Kitto, & Martin Tilley, behind a wingsuit. They used standard, toroidal, and midskirt vented designs. The focus is on BASE but it is interesting testing in any case. http://base-book.com/pc-extraction-and-inflation

I think in Poland they have a 20 year rule, so older reserves do become available at a moderate price. (One such seller is a regular poster here.) I'm ok with older reserves in general, but you would want to think about how long you want to keep the gear... after all, in 10 years it'll be 30 years old. Also, whether the Raven 1 is appropriate to you in terms of wing loading, as it is an older design. And if you were getting into higher speed flight (eg, head down), perhaps a canopy with more modern features like spanwise bracing would be more welcome (even if another canopy might actually be certified to the same level -- like TSO-C23c cat B -- and could be argued to be similar). Is it a better deal, for example, to pay more for a 10 year old PD reserve or similar?

Did you save the main container? When I cut up an old rig to use as a cutaway harness, I saved the main container to use on the belly. Had to build a new top flap / cover flap, but saved the back and 3 flaps. The rig had a closing loop anchored at the 'backpad' -- convenient for accommodating different canopy sizes. Gaps between the top and side flaps, where the risers go down into the belly mount, there small velcro tabs were used to close the gaps. Put a couple straps on the back so one could tie the belly mount off to the cutaway harness -- various ways possible there, whether with clips (as long as they can't snag line), velcro, cord, etc. I also added some short channels with just a bit of velcro down the main risers of the cutaway harness, so the risers of the belly canopy could be kept a little more out of the way instead of flapping around. (Although usually I would be deploying right after a very short delay, just hopping out back to wind, so I haven't always used the velcroed channels.) For the cutaway handle, I can leave it in the regular place or put it on chest strap velcro. As you said, to put it in a less cluttered location. I also made it a loop style handle -- just sewed webbing around the yellow cable -- and made it white, different from any other handle. Big and easy to find when you really need it. As for the pilot chute, since most of the main container was saved, but turned around in front of me, now the belly mount has a left sided BOC...

Let's also remember last year's news - so to summarize: Units manufactured Jan 1, 2016 onwards only have recommended (not mandatory) maintenance and Jan 1, 2017 onwards are the same, but now with a 15.5 year life (and 5 year maintenance intervals suggested) So the latest units should be able to compete well at least with the M2. The optics are a lot better now for the Cypres -- not the shortest life now, and no longer mandatory servicing. (Hopefully the battery lasts the full duration, but the M2's is expected to last 15 years. Cypres is $120 more than the M2 but has a longer track record, permanent firing altitude offset, and nowadays has multi-mode capability.)

I have just put a few skydives on BASE canopies, and used to jump a 'Foil 282 for accuracy including in competition. I did a couple jumps on a vented Blackjack 260, and one on my Troll 265 MDV. In my very limited experience, I did find that the BASE canopies, even vented ones, just didn't "shut down" as well as the Foil could, for sinking it in, in light winds. At least I tended to overshoot a foot or so when mentally still being used to the Foil. The vented BASE canopies did glide almost effortlessly between stalls and forward flight however. One could stall, rock back a little, have the canopy stay well inflated, let up a little on the toggles and it would transition almost seamlessly back to flying, without any great pitching or being thrown around. So I even did that at 150' on final. But that's all just initial impressions and someone with more experience might have a different opinion. Certainly the region of sinking it in vs. starting to stall it, needs to be explored, carefully. In any case you can go and play with your canopy.

But what actually happens in real life? UPT says they can't "endorse" any other canopy. But there is the usual rigger discretion in mixing and matching. And we've had Precision posting just last year on dz.com about packing their reserve into a Sigma. It was done right at UPT ... although it was being called the Relative Workshop in the video so is quite ancient. Mixing tandem components, even mains, has been a debated issue in the past. In any case it is probably best to stick with the VR360 reserves...

M.E.L.: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?username=masterrigger1; Pete Swan: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?username=PeteS; But I have to ask, drifting the thread, you still jump the Onyx? How do you find it? I remember when "Atair Dan" was hyping the Onyx as the next greatest thing on dz, over a decade ago. While I have put a bunch of jumps on a Cobalt 75 and enjoy it for what it is, I got to jump an Onyx and didn't like the crazy light front riser pressure; felt pretty dangerous just as a first impression. Despite all the fancy crossbracing, the profile of the canopy in flight didn't look all that smooth on the topskin. The guy who owned the Onyx later burned it in the year end bonfire; he disliked it that much that he didn't even want to sell it off cheap to anyone. Anyway, you have a couple interesting rare canopies.