pchapman

And what's the opinion on silicone slider bumpers that are not tacked down on reserves? I've seen some reserves like that while rigging. Is it a common practice? One time, I opened a rig to find that one silicone slider bumper had slid off the rapide link. I'm not a highly experienced rigger, but I like to have reserve slider bumpers tacked down, even if they are silicone and "should" stay in place on the links. As far as how to tack silicone bumpers, I prefer wrapping the supertack around the whole bumper top to bottom, rather than piercing the bumper and doing a short loop to the side of the bumper. The latter method looks a lot neater & cleaner, but a crack can initiate where the silicone bumper is pierced. I've replaced the occasional bumper on both mains and reserves after they've split partially open. Comments by riggers?

Finally got registered, 5:30ish Eastern Daylight Time. Anyone know where the numbering started this year? Last year, order number 1043 meant registration #43 as far as I could tell. This year I'm 1657.... what does that mean?

Just to expand on the above comment, and not on all the rest of the argument: Most of the building rescue chutes marketed did seem to be based on paraglider reserves. Most were rounds; one was a Rogallo design. There are a couple of the latter certified in the paragliding world. That's an interesting step between having an unsteerable round (most but not all paragliding round reserves are unsteerable rounds), and having a ram air (with its forward speed and steering ability, which may or may not be beneficial to whuffo users). I think one or two of the marketed designs were based on round BASE canopies (as used for water jumps). Paragliding rounds DO normally have apex vents. But since they usually have a pull-down apex for fast inflation and low descent rate, yes, they can be more prone to oscillations than a round skydiving reserve, depending on the design, bridle length, and conditions of use. Paragliding reserves may not undergo certification testing as extensive as for FAA TSO'd reserves, but any commercially successful ones (at least in Europe) do undergo a certification process that involves drop tests for structural integrity at a particular speed, and tests for descent rate. Generally they are designed for very quick opening, given the low altitude and speed environment they are usually used in.

For what it's worth, the content of the bill (which is available online at a gov't web site) is very generic, giving the provincial government the ability to set standards for parachuting equipment and issue permits for freefallers who use parachutes. Completely open ended, with no mention of exactly what they might require. Some trivia from the bill: Freefallers using parachutes would have to carry their permits with them. Freefalls of less than 10m (33 ft), into water at least as deep as the freefall, would be exempt. It all reads like a joke, and has little hope of passing for reasons previously mentioned. It does continue to attract the media's attention in Canada to skydiving, given that there were a couple skydiving inquests earlier this year in Ontario and Alberta. One inquest finding (which has no weight of law) stated that all student operations should cease until new regulations are in place. I've heard of drop zone owners occasionally being asked by whuffos in the past months, "So I guess you guys are shut down?". Although usually any publicity is good publicity, that's taking things too far, and doesn't help DZs here in Ontario which are already suffering from reduced business due to poor weather this spring.

I'll go back to this old thread because I now have data from JumpTrack curves for some of my jumps in SLO mode WITHOUT a wingsuit: The quote above appears accurate, although L & B didn't mention it. For example, in a sample of 10 jumps, in Normal mode, my ProTrack recorded opening speeds usually in the 85-100 mph SAS range (with extremes of 78 to 102). In SLO mode, during a similar number of jumps, the recorded opening speed ranged from 20 to 75 mph SAS. So in SLO mode the computer seems to be much more variable in its choice of what time to call the time of opening. The slower speed at the indicated time of opening does result in a lower indicated opening altitude, but only by 100 to 200 feet. That's based on looking at the JumpTrack graphs. If one selects an arbitrary 90 mph for Opening, then the opening altitude is 100 - 200 ft higher than shown by the ProTrack (with its 20 - 75 mph at opening in my data sample). (FWIW, these were all flatfly RW jumps followed by a track until just before deployment, using a Sabre 135. A snivellier canopy might show a slightly larger difference between SLO and Normal mode openings.)

That's in one of the British "Wally Gubbins" skydiving videos. Late 1980s or thereabouts.

Any comments for the wingsuit newbie on efficient turns, in the sense of not increasing fall rate a lot or not losing a lot of altitude for a given turn angle? The lift available at normal wingsuit flight speeds just doesn't seem to make for high-g turns, and there's a lot of momentum to be redirected when making a big change in one's velocity vector. I'm thinking I might tend to be diving off to the side a bit much while turning. A more agressive, head high flare type turn might get one turned faster with less initial altitude loss, but then leave one with less forwards speed and subsequently more sink. For the very low glide angle flight regime of a wing suit, more gentle turns may be best at not losing as much altitude, by keeping the speed up during the turn and therefore the lift too. But what do I know! Supporting data: On my first few wingsuit flights this past weekend, JumpTrack readouts were giving 55-60 mph SAS in straight gliding flight and peaks of 90 mph SAS during roughly 90 degree turns. [GTi flown by a novice, 150 lbs body weight] (Wingsuit flight #1 on the weekend was also jump #1000 for me. Yee hah.)

When making a transition that is fairly major, one way to make things easier is to pick & choose one's wind conditions. Don't jump in low winds; wait until the winds are moderately strong. It's a simple concept that people must use, but I haven't personally heard it mentioned in all the many discussions about downsizing & wing loading. Perhaps someone is concerned that a newbie will overdo it and jump in very strong, gusting winds? The difference between a no step landing and having to 'run it out' can easily be created by common changes in wind strength. Off the top of my head, wind can easily be the equivalent of a couple sizes difference in canopy. Of course the flight dynamics of a small canopy will still be different. (My first jump on anything other than student canopies of 288 or 249 ft. sq. was a 172 ft sq Firelite. Sure it was scary in the air how fast it responded to small toggle inputs, but the landing was an anticlimactic no-stepper because of the 20 mph wind.)

T Looking at manuals for 1980's rigs with square reserves in them, the canopies were flat packed and weren't molar'ed. There were some interesting pretzel-like methods to get a canopy into a freebag back then. This brings up the issue of having to follow the manufacturer's procedures (according to the FAA in the USA), but at the same time using experience to know when there are better ways to do things, that are already standard in the industry.

For non-tandem rigs, having no top grommet appears to have been a common variation in bag design in the 1980s. Larks head the bridle ontop of the bag, and larks head a short section of bridle between the canopy and bag. The design must have fallen from favour once collapsible pilot chutes emerged, as the kill line designs normally used require the kill line to be connected through the bag to the top of the canopy.

Long post... Whether a dropping feeling is actually noticed depends a great deal on one's mind & body, in addition to the requirement to have some sort of acceleration happening. The nature of the acceleration has been largely discussed already, with some of the bad physics having been cleared up. The "mind & body" may mask the dropping sensation in several ways: - Habituation - Skydivers get used to it and don't notice it any more. No different than wearing glasses and not noticing the pressure on the nose after some time. - Total acceleration - This one I haven't thought fully through but others have suggested it. Whether exiting from a balloon or a fast King Air, the downwards acceleration initially will always be about 1 g (before air resistance builds up, and assuming one isn't in some sort of tracking position to do anything other than a ballistic drop). However, with the strong horizontal deceleration going on, the vertical acceleration may be less noticed by the body. I don't know, however, how much that is because of stronger total acceleration, or because of the masking effect of another strong sensation -- the air blast which is higher than a skydiver might expect when jumping from another slower aircraft. - Masking effect of other external sensations - For example, the stronger than expected air pressure as mentioned above. - Masking effect of the brain - When we have something else to concentrate on, we may not notice sensations we would otherwise notice. For example, when jumping on a very cold day, we might notice the frigid air when the door opens, but have almost no memory of it during the freefall itself where we are strongly focused on the maneuvering and formation work. - Masking effect on internal body sensors - I have no idea of the physiology of all this, to what extent acceleration is sensed through the vestibular system (otoliths in the ear's canals etc) versus through proprioceptors ("nerve endings in the muscles and tendons and other organs that respond to stimuli regarding the position and movement of the body" - eg - stomach-in-the-throat feeling). If there are other strong stimuli, such as tensing the muscles or rotational accelerations, the body may not sense the downwards acceleration as readily. I'll come back to this point. My own experience as examples: - As an AFF student (well, PFF student in Canada) I noticed the falling feeling for a few seconds on the first few jumps but not later on. Largely a matter of habituation. The feeling was noticeable because it was so unusual, no matter how strongly I may have been focused on other aspects of the jump. For other people, the balance between these two factors might be different. - As a novice jumper I could get the falling feeling again by doing an exit in an unusual body position. Doing my first couple exits from a Cessna on my back, I got the falling sensation again. I wonder if "trying to fight the fall" somehow makes it more likely to get the falling feeling. On those first back to earth exits I wouldn't have had great body control on my back, and so there could be some feeling of 'I'm falling and trying to get in control'. An experiment to check this would be to compare novices doing their first jumps back to the wind, with one group trying to maintain their body orientation, versus another group being told to just relax and allow themselved to tumble. Assuming the latter group were already comfortable with regaining stability & getting back to belly to earth, then I think the first group might have more of a falling feeling as they try to tense against something but feel they have little support. They can flail their arms but can't keep themselves from a tumble. - Perhaps the most interesting observation in my whole post: Bridge Day last year was my second Bridge Day. On the first jump, flat and stable, I felt a little bit of dropping sensation. On the next two jumps I did aerials, and didn't remember the falling sensation at all. On the final jump I went off flat and stable but in in a very relaxed, non arched position, looking down at the girders just to take in all the visuals. Wow, that time I felt an intense falling sensation, that lack of support, getting sucked down by gravity. It is so hard to try to separate all the factors and determine which ones have the greatest influence in a particular situation and why. During the aerials jumps, my focus on getting the maneuvers right may have been a factor. Also, proprioceptive information on the falling may have been masked by the other accelerations happening -- the rotational acceleration going into a layout backloop for example. But are the total magnitudes of such accelerations, even at head and feet, very big compared to the initial 1g downwards acceleration? I haven't done the math. Having muscles tensed to hold a particular body position or do a maneuver might mask the body noticing acceleration. So being relaxed may allow the body to better sense the acceleration. That fits with my Bridge Day experience. But this can be opposite to what happens in some situations, where being relaxed actually equates with being comfortable with a situation, and not feeling the falling sensation. For example, a student jumper who feels good about jumping can exit the airplane and stay relaxed, and may not notice the falling sensation as much. The student who is frightened by the drop will tense up, get the sensation, kick their legs, or whatever they might do to 'fight the fall'. Muscle tension and movement doesn't fully mask the body noticing the acceleration, and the mind is primed to notice it in that case. That suggests the mind has a much greater effect than the body in this falling sensation issue.

Wow, I'd like to see that. Who has a copy? See it, not do it. The Lemmings Extremes video shows some of the craziest jumps at Bridge Day over many years, both good and bad ones. The video shows a Mr Bill that was landed from the Bridge, in the river, not on dry land. Since then no Mr Bill landings are allowed; the second person is supposed to jump & deploy. The video was produced by Will Forshay, who died about a year ago in an aircraft accident (non-skydiving). His site, http://www.lemmingsvideo.com/ is still up. I have no idea whether someone is taking care of the site & his videos or not.

Option 3, cutting away the reserve before going to the main, does look tricky to carry out in practice. But I do believe it has been done. I recall a case I read maybe 10-15 years back, in the USPA magazine, where a woman had a premature deployment, ripped up the reserve as she passed the aircraft tail, cut the reserve away with her hookknife, and deployed her main. She had only about 40 jumps, if my recollection is right. Pretty cool thinking and a steady hand for that many jumps...or for any number of jumps.

For the record, I emailed L & B and received this reply: "In the manual on page 46 you can see the specs when the unit is put in SLO mode. This setting does not affect the exit and opening altitude calculations if you leave the unit is this mode. Best regards, Mads Larsen"

I attended a mini-airshow at a big paragliding festival in St Hilaire, France, last autumn. The town, spectator area, and paraglider launch are all on a plateau on the side of a mountain ridge, with a wide valledy 2500 ft below. During the airshow Loic or one of his buddies jumped at a normal altitude, flew his wingsuit until over us spectators, and at about 500 ft above us turned and glided out into the valley, around a corner of a ridge, to deploy somewhere out of sight down below. (He was being conservative with his distance from the crowd, given his skill level, whatever the French air show regs may have been.) When a Twin Otter dropped an RW load over the valley, we could watch the 20 way split up, track away, and then deploy level with the crowd. How odd to be standing on solid ground while looking towards the horizon at jumpers deploying. (Although not skydiving, the aerobatic aircraft acts looked impressive too. A plane could pull up from below the lip of the ridge, do its gyrations, and disappear down below again.) A unique perspective for an airshow.

If one has a ProTrack set in SLO mode to better record wingsuit flights, what is the effect of leaving it in that mode for regular skydives? For example, might it affect exit or deployment altitude records compared to normal? Is there ever any time when SLO mode's "increased sensitivity" to pressure change & altitude causes errors? I'm wondering whether to just leave the ProTrack in the SLO mode all the time, or switch back and forth depending on jump type. No info seen in the archives about this issue.

Even before the new licence versions, the Canadian numbering system had a glitch or two that made the numbers not purely consecutive. I seem to recall that with at least one licence level, there was an administrative error one time (mid 1990s?) so there was a gap in the numbers. So the person with licence 900, say, might actually be the 850th person with that licence.

An example of CRW weight carrying: At the Worlds in Gap, France last year, the Australian CRW team consisted of 3 hulking guys and one skinny guy. The latter wore on his belly what looked like a tersh at first sight, but was actually 40 lbs of weight attached by extra D-rings.

The E licence requirements had some weird stuff in it! Here they are, paraphrased from my early 1990s manual: -- there are some residency requirements -- 500 jumps (when the D required only 200) -- 2 hrs 30 min freefall. -- 5 intentional water landings, one within 15 seconds swimming time of a target buoy -- 5 night freefalls, one at least 30 seconds with landing within 10 metres of target -- land within 1 m on 5 consecutive jumps, and within 1 m on at least 25 jumps total -- compete in the Canadian Nationals in two separate events, or in 2 Nationals in one event -- style set in 11 seconds or less (International Cross) -- have a class B instructor rating -- have a class A rigger rating -- 25 RW 4-way jumps including a) 5 different jumps with 5 or more completed FAI formations b) 1 night RW jump as the agressor c) 5 camera jumps, supplying a photo as proof of ability -- make one 45 second delay using supplementary oxygen [The dodge on that one was that it didn't have to be a high altitude jump, so the oxygen system could be crude and not necessarily be able to keep you alive at extreme altitude!] Privileges? Other than bragging rights for a cool, low licence number for having to do a lot of jumping through hoops, so to speak, all you got was: The FAI sporting licence fee is waived by the CSPA. [At the start of the 90s a sporting licence was needed to just compete at the nationals; now it is only for going to the Worlds or similar competitions.] Peter Chapman CSPA D-1014 (arrived in the mail a couple weeks ago!)

I still do jump a rig with a round reserve about a quarter of the time. It's in my old, 2nd rig. Until 2002 it was my only rig, for my first 500+ jumps. It's great to have a spare old rig! (for busy days, CRW, trashing, Bridge Day, Birdman, whatever) I think skydivers often reach a certain comfort level with the the risks associated with their sport when they are first getting serious in the sport. Every safety innovation that comes into practice later on may be considered nice, but not essential. No Cypres? Round reserve? Some jumpers who started in the 1980s might have no problem borrowing a rig like that for a weekend, while the proportion of jumpers who began in the mid 1990s who would think the same thing, would be a lot lower. Some of the difference is due to different assumptions of risk, and some is just due to different levels of familiarity with how to use the older equipment safely. I have had one ride on that round reserve, going backwards in winds that were 15-18mph on the anemometer. A little scary given a few obstacles about? Sure. But it got me down safe. The Phantom 24 hadn't been used by me or previous owners in the 18 years since it was built ... until I took up CRW. I'm glad to have the square in my newer, smaller rig, but have no problems jumping the round. Local issues affect ones choices too. I'd probably be less happy jumping with a round reserve if I were at a DZ surrounded by housing developments instead of open fields and a few small wooded areas.

I can't give a definitive answer but can add a little bit of related info: Although it is above the "0-3" brand-new value for F-111-style fabric, 5 sounds acceptable. Worn from packing or whatever, but not ragged out. The very limited evidence I have for this: I saw some test results by the Canadian military on a about a dozen used civilian student MAINS like Mantas. These were canopies in current use at a large Cessna drop zone, with ages likely in the 5 to 10 year range. (But with many sets of gear, no one canopy had an excessive number of jumps on it.) The desired limit was no more than 13.0 cubic feet per minute. That's what it showed on the printouts, but it didn't say how "hard" a limit it was, especially given that a canopy with one cell outside the range would not be nearly as poor as one with most of its cells outside the range. Most of the used canopies had porisities across different cells in the range 6-10 cfm, with an average of perhaps 7-9 cfm. The worse canopies would have much wider variation, such as measurements ranging from 6 to 22. Tests were done typically on the upper surface nose of all cells, or also the upper surface tail for the center cell. There were no really clear trends across the span of a canopy, but sometimes one could see higher porisities on the end and center cells. This matches the cells PD says to test when doing reserve pull tests. Interestingly, a saw a couple canopies where exactly the reverse occurred, with lower porosities at the center and ends -- but those were canopies where the center and end cells were a different color. So different colors may wear slightly differently. That's a topic I've never heard much discussed in skydiving, other than for particular bad batches of fabric, or about faster deterioration of some fluorescent colors in UV light. I think in paragliding and BASE jumping there's been some talk about the subject. For the record, the porosity testing used a test area of 38 square cm, and 125 Pascals air pressure, using a "Textest FX 330-III" machine. (I've used the term "porisity" as that's what skydivers say. In the aerodynamic decelerator design world, porosity has a slightly different meaning, and the term permeability is used instead.)

For the Vector II, for example, the manual lists 15.5 or 18.5 ft depending on canopy & rig size. (Actually the Vector III manual states the same, but I can't say either way what is currently the practice.)

What about partial hard housings -- I'm talking about those where there's a metal housing behind the neck, but the sections that stick up from the harness to the riser are soft. What's the opinion on those? Some Rigging Innovations rigs are like that. Is it still current practice? Who had fully soft housings? Javelin, any other rigs?

Another term that could be used for desensitizing is "dissociation". As has been discussed, this situation can lead to the need for greater risks to create the same level of pleasure. It also means people in extreme sports need to rely more and more on their minds to evaluate and control risk. Millions of years of evolution are (partially) out the window, for basic human instincts about the fear of falling can't in themselves keep us safe. Once we humans start adding skills & equipment that allow us to survive in an otherwise dangerous environment, we have to think through a situation to decide whether it should cause us to be fearful, or at least be aware of a risk. This isn't to say basic instincts don't have their place, as they can still signal potentially dangerous situations so that we start to think about the consequences. And people with high skill levels in a particular area no longer have to think as much about what they are doing, for the actions become ingrained and natural. And everyone needs some desensitization to deal with things that become more common in our lives. Hurtling around at 35,000' at 600 mph isn't exactly natural either, but at some point most of us just accept the potential risks and take airliner flights without being worried sick. When I find myself moving around near to the top edge of a cliff, most natural fear is suppressed because of my experiences with that sort of environment. I almost need to stop and think whether there should be anything to be afraid of -- and to what degree and for what reasons. There are so many different ways I might be in danger or relatively safe. Maybe I'm in a climbing harness and fairly safe because I know I've rigged a proper rappel and am hooked in properly. Or I'm in a climbing harness but just came off the top of a route and have to remember that despite the apparent security of a harness, I'm not hooked up to anything, and have to watch my step. Or I'm in a paragliding harness and the glider has inflated correctly above me so I can fly off OK. Or, for BASE jumpers with more experience than me, you would know that you can jump off and live, as long as you can get to the edge with a solid footing. Fear is no longer something that just happens; it takes some conscious thought to figure out whether there is anything to be afraid about.