pchapman

Yup. Single point connection, no chance to at least haul on a riser to sideslip a little. No reserves normally I think. Apparently towards the end of the war they had a different system, but they weren't doing big drops (any drops?) by then. I think books say they didn't learn the more modern roll but were expected to fall forward - which might be something someone on the other side just guessed by looking at how they hang under the canopy. But I have unpublished reminiscences from a former Fallschirmjaeger and he suggests they practiced rolling every which way. If one doesn't have directional control of the canopy, who knows which way you are going to have to roll anyway. Photos suggest the Germans went without a reserve. The British system was also with no reserve. The British canopies at least had a better and more reliable staging method than the US had, deploying the lines first before the canopy inflated from a bag. (As opposed to 'canopy first' where it was inflating before the lines were paid out). I believe the German system was similar to the Brits in that way. That's all mostly from memory of different books so others might have better detail. One local former skydiver in my area, first jumped in '42, courtesy of the German Army. He missed Crete and all that, so ended up being used in ground forces in Italy. It is his reminiscences that I have. I could go through that some more and find some details on German paratrooper training.... From "Fallschirmjager- German Paratroopers from Glory to Defeat 1939-1945", a training photo: (Must be early in those troops training cycle as they aren't kitted up at all.) [inline GermanParatrooperTraining.jpg]

There have been similar threads before but I'll play again: For my regular sport canopies: Jumps 1-40 -------- Manta & similar Jumps 41-590 ------ Titan 265 (WL 0.65) Jumps 591 - 775 --- still the Titan (or a Parafoil) but 35 jumps on a Sabre 135 (WL 1.25) I bought Then after only 90 jumps on anything above 1.2 wing loading: Jumps 775+ -- FX 88 (WL 1.95-2.05) (Tried it out at jump 550 but didn't buy until later) The situation is a little different with borrowed canopies where may downsize a lot faster than for one's regular canopy -- there it was more like going from 200+ sq ft, downsizing through 3 smaller canopies over 12 jumps, and then going to a Jonathan 92 (WL 1.9)for a few jumps from jump #205. In the old days, downsizing meant "do a couple jumps on a canopy and if you feel comfortable with the flare and twitchiness, you can go down another size". It probably helped that I was a pilot & aero engineer. Still, getting into ground hungry crossbraced canopies was a huge step.

It does sound odd but the guy has a point: If one is sending in a Vigil 2+ just for batteries, and not an entire system check, and it has a separable cables, why not just send the box in? No need to feed the cables through slots all over the rig again. (Not sure about going jumping in the meantime with loose cables left in the pack tray, but I suppose the ends could be secured in the AAD pouch.)

First impressions: External cable connector attachment - can change cutters without opening the Vigil. Has a clip that prevents external connectors from pulling out accidentally. (Cypres doesn't, although it generally isn't a problem.) It is unclear to me if the cutter cables have changed?? Presumably they are, as the ends of the cables are visibly different but nothing is really said about it. We've moved to Arabic numbers: It is the "2+" and not the "II+". Doesn't arm until 1000 ft above the ground. Quite different than the Vigil II's behaviour, and more like a Cypres (with its 1500 ft).(Exception: When there's a negative altitude offset, it is 1000 ft above the offset level.) The Vigil II had the warning about having the plane climb out of the + or - 150 ft range from the runway and not linger a long time there, otherwise the Vigil might not sense enough change to register that it had gone airborne. This range has now tightened down to + or - 90 ft. Screen pixels invert to show when it switches to Airborne mode. Helps with the "what the heck is the AAD thinking?" question that affects different AADs. Useful if dealing with movement in a car, different altitude landing and takeoff areas, etc. After one incident some years ago where the Vigil fired in the plane, the manual got the warning about not opening the door "while in the activation zone". That always seemed a copout, admitting their activation logic was shaky. Now the restriction is lessened and is more specific: Don't open the door if under 1640 ft and there are Student mode Vigil's aboard. The jump info (freefall time & speed) displays for 2 min after landing, instead of only being accessible within menus. A negative: Battery change can't be done by a rigger any more. They say not to open the case, don't give instructions, and say it voids the warranty. Have to send the unit in to Vigil service centre. That's a big change from the "don't need to send it in" philosophy. Same battery pack number and expected lifetime and mandatory 10 yr replacement. They still say "No scheduled maintenance required", but that might be considered debatable since it is now "send it in at 10 years for the battery" (unless the battery already was changed). Hmm, presumably they won't put in a new battery at the 20 year point. Wonder what happens if someone sends it in for a battery at 19.75 years? Will batteries be sold anymore once the last Vigil II times out at 20 years? (If rules lawyering, they say 10 years OF USE for the battery, so that time could be considered to start when you receive the unit and turn it on, not a few months before when it left the factory. Whether for the Vigil II or 2+, that introduces uncertainty into mandatory replacement intervals.) The Vigil II+ doesn't need to be sent back to a service center if it gets wet, to the extent it does in a typical swoop pond. Originally the Vigil 2 was good with water, with its filter not needing replacement like the Cypres 2. But a service bulletin backpedalled a whole lot on water resistance (PSB 9), due to some units getting damp inside, requiring the Vigil II to be sent in if the filter got wet. Now on the 2+ you only need to do so if immersed below 1.8m or more than 24 hrs. They did upgrade the certification level from IP67 (0.5m down/30min) to IP68 (1.8m down/24 hrs). The main box remains the same size and weight, despite the cable connector system being modified. A change in philosophy: Instead of saying that it fires (in Pro mode) at 840 ft but up to 1100 ft depending on body position, they quote that it fires when measuring 1100 ft, and then note it may range 840 to 1100 ft actual altitude. They strongly recommend having a fully open canopy 1000 ft above the activation altitude. I'm not sure if they are thus suggesting being fully open by 1840 ft or 2100 ft. That's a little disquieting although perhaps just cover-your-ass language. I always thought you wanted a fully open canopy by that 1100 ft level, so there would be no issue of burble and changing body position. There are still warnings about if one has a LZ at a different altitude than the previous takeoff zone, and then launch from that new level. They always wanted a switch off and on to be sure the new ground reference level is set. (They used to say 100ft, now 90 ft, no big deal.) But I'd think that if one were at the LZ for any length of time, it would self adjust? After all, it is supposed to account for air pressure changes during the day, AND now you do know for sure if it is in ground mode or sees too much pressure change too fast and goes into airborne mode. Is there something I'm missing or are they just being conservative in suggesting rebooting the Vigil? I haven't gone in detail over the altitude adjustment stuff, which is both for adjusting the desired firing altitude, and LZ level differences. As before, a single adjustment routine is used to cover both cases. There was a big thread earlier this year about adjustments, which included some confusion that people had over how the Vigil handles that. I haven't compared the details, but the new section is expanded and looks like it is much more clear on what happens to the +150 ft no-fire zone, when an altitude correction is applied. Read it carefully, as one gets different effects depending on whether one is landing higher, landing lower, or just trying to increase the activation altitude in general. I wouldn't say it is some brilliant rewrite of the manual, and it is now chock full of varying font sizes and still has a million warnings. But they have tried to clarify things. It would be nice to have a summary sheet of changes instead of having this kind of search game. Maybe later they will have one. Nice to see Vigil coming up with new stuff.

Actually the 2nd picture on the page you found is much more useful. Unfortunately it has text so small it is hard to read, and cannot be expanded. (Zooming in your browser helps a little.) --> So I've added a copy of that below. It looks like it is only a math model, so not guaranteed accurate to reality. It is also 2-D, so it doesn't look at wind around the sides of a building. Nor does it get at the turbulence and variation in wind speed bound to occur. The obstacle is 20m high and 60m wide, with zero porosity -- rather like a large hangar perhaps. The vertical and horizontal scales are not the same -- stretch it out about 5 times horizontally to be like an actual photographic cross section. Ignore the yellow bar - that represents a wind turbine the original researchers were looking at, downwind of an obstacle. Unfortunately the actual wind speed is not shown, and surely the effect will vary somewhat with wind speed, even if dealing in percent changes. If a number 95 is shown, that's 95% of the original wind speed, or a 5% velocity deficit as is sometimes said. Lets say for our purposes, a 10% loss of wind speed is "Significant" rather than trivial. Who knows what an appropriate level really is, especially if turbulence and gusting is also included. And 20% loss will be considered "Serious". Winds stay above 90% of the original value only at 40m up, and 80% at 33 m. Thus: Significant changes in wind speed can occur below 2* the obstacle height, and Serious changes below 1.6* the height. Horizontally, winds stay above 90% only from 365m onwards, and above 80% from 257m onwards. Thus: Significant changes in wind speed can occur downwind at up to 18* the obstacle height, and Serious changes downwind at up to 13* the obstacle height. [Edit for typo - numbers were reversed] At 10 times the obstacle height downwind, one can have wind speeds as low as 74% of the original! Again, this is just the result of one math model for which we have no background references - use it as an example but don't take numbers as gospel! Because it is 2-D it may be a little pessimistic compared to any real obstacles that aren't too wide. (Like a single building, but not a forest, although a forest is more permeable.) [inline wind_speeds_behind_obstacle_(zoomed)esru.strath.ac.uk.jpg ]

Which may or may not be relevant to the chest ring question, depending on what rings you are talking about.

Soo, this is actually the dominating reason why trackers stay longer in the air, right? No. Trackers or inclined barn doors or airplane wings all still work due to a combination of lift (defined as the force generated perpendicular to the line of flight) and drag (defined as the force generated parallel to the line of flight). This principle about 'not being able to treat vertical motion while ignoring horizontal motion' is about aerodynamic forces in general. It applies equally well to a round cannonball that is generating no lift at all. If it is zooming forward while dropping a little, with all its speed it is generating a lot of drag, which does indeed slow down its acceleration vertically. (Which if you don't understand the whole picture, is like some kind of magic anti-gravity lift. But it isn't lift since there's no force perpendicular to the line of flight.)

Ok, although I've been snickering at some of the stuff in this thread, I'll give you a serious answer about how it works to help you and others learn this. Let's say a heavy round ball is dropped vertically, vs. dropped from an airplane moving fast horizontally. Drag tends to change with the square of the speed. I'll skip all the real world numbers and we'll just say that something falling with speed 1 has a drag of 1 squared, which =1. Speed 2 gives drag 4, in some system of units. Lets say we compare the drag when both balls are falling speed 3 vertically, but one ball is still moving forwards fast, lets say speed 10. The drag on the ball dropping vertically is 3 squared =9. For the ball moving forward, we can't just say that the vertical speed is 3 so the drag that affects how fast it is accelerating downwards is 3. Instead we have to look at the whole velocity vector. Speed 3 down and 10 forward = 10.44 speed by Pythagoras, at an angle 16.70 degrees below the horizon. Total drag is 10.44 squared = 109. The vertical component of that is 109*sin(16.70 deg) = 109*.287 = 31.28. Voila. The ball falling straight down will accelerate straight down based on a drag of 9, while the ball arcing down with a lot of horizontal velocity, will accelerate downwards (at that particular moment in its trajectory) as befits a drag of over 31. So it will be accelerating downwards a lot slower. There's a huge difference in the drag values, even when one is looking only at the vertical direction, despite both balls moving in the vertical direction the same speed. At slow overall speeds you might be able to make approximate calculations for the vertical speed only, just by looking at the vertical speed of the object, treating the horizontal dimension as independent. After all, we might use a skydiving table that says that after 5 seconds of fall, a jumper will have dropped roughly 366 ft. In reality, that will differ a little depending on the forward speed of the airplane (even for jumpers all on their belly and 'falling straight'). If you want the calculations to be correct, you have to do the trigonometry and not just treat horizontal and vertical movement separately.

Which reminds me of a jumper who can draw a good duck cartoon. I thought in her case it was a 2 way exit, broken arm, and then a broken femur when the one handed landing didn't work out. [Ref.: http://tailotherat.blogspot.ca/2012/09/how-i-broke-my-arm-and-leg-part-i-dont.html ] In any case, trying to figure out how to land one handed, when you just broke something, isn't necessarily easy, especially if you haven't thought it through before.

Sounds like an invitation to tell tales. Where I jump there were a couple Caravan exit injuries 4-5 years back. Both cases were just simple 2 way RW jumps, one person inside, one outside. In one case, a jumper cracked their elbow (needing hardware), in the other case, an arm was broken. Landings had to be done with one hand in both toggles. In both cases, the exit was poorly coordinated, with the person outside just dropping down, and/or the person inside not pushing out. Either it was two newbies together, or one newbie and one experienced jumper. So there are some basics for new jumpers to learn. I nearly broke something on a C-182 tandem exit. I tried to overpower a student who grabbed the strut during climbout, while I should have taken more time to smack his hands and have him let go. While I figured he'd just let go when I pushed out, he clung tight, so I barely got out the door and then fell straight back and down, left lower leg still in the plane. Wrenched my leg as it got yanked around the door corner as we tumbled off the plane. Then there's the general door rash on Caravans and Otters from hitting the back edge of the door - people not diving out enough to the side, or aiming too much for the back corner of the door when following others. I had that once when I was new to the Twin Otter, scraping my ankle badly. (It didn't help that I had metal just under the skin there at the time - metal sandwich of my skin.) A Cessna step is of course a source of danger, especially for people who slip, or newbies not pushing off right and nearly eating the step. Haven't seen an actual injury from that, but there must be some nasty ones out there. There are tales of bad grips on Twin Otter flap tracks, by front floaters without a good outside bar. There was a tale going around maybe 20 years ago from the US, of someone catching their glove there. Someone else on the load saw it still in the flap tracks, grabbed it, gripped it with their teeth during the dive, and when returning the glove to its owner on the ground, found his finger still inside.

Non-relevant. Bullet is moving relative to the air mass. Aerodynamic forces on the bullet have to be calculated as a whole, and can't purely be calculated purely on horizontal and vertical movement separately without reference to the other. The simple way to put it, is that there are significant lift and drag forces on a high speed object (relative to the air mass, not the earth or solar system) which are different from one dropped from a standing start, and thus affect the time-of-fall.

Because zey are better zan uzzer pine seeds! Surely you've heard of thermals. A dandelion seed or pine seed can easily get caught up in them, including ones in storms. A heavier object with a greater descent rate like a glider takes some skill to go far with thermals. A steel ball, well, that's not going to go anywhere except in a tornado. [I have some German heritage so I can make the joke even under the rules of political correctness.]

And what has become of those fine, nimble-fingered folks sewing in Honduras?

(Just hitting reply to whatever post is last) FWIW, Dyneema and Spectra are basically the same chemical composition spun into a high performance fiber of similar (but not necessarily identical) physical characteristics, just from different companies, and both Cypres and Vigil loop material are both listed at 450 lbs strength. We do indeed have the problem that for AAD's, the rules we work with are silly, as we have to do anything the manufacturer says, for whatever reason. We don't even seem to have that allowance for interchanging compatible components that riggers can use for other parts of the gear under FAA rules. If someone wants to have an "out" to the Cypres requirements, the section in the Cypres 2 manual that says "Only use original CYPRES loops / loop material, pull ups, and discs when a CYPRES is installed in the container" is prefaced by a statement in bold saying "The following tips are only brief suggestions." A tip or a suggestion is non-mandatory. Make your own choice.

I think someone needs to ask PD to clarify / dispel rumours, since this is a significant thing when it comes to certification. (My thought was that they didn't get a waiver in the end but I don't know what is true.)

That's an interesting point you make about military surplus equipment, one that most of us haven't had to deal with! Does anyone else have confirmation that that's the only possible legal interpretation of the FAR's? About how "high altitude" parachute systems doen't qualify as an "approved parachute" for civilian US use? I'm not disputing that GGGGIO knows a whole lot about the MT series of rigs, but we know that interpreting FARs is not always straight forward. I can identify at least 3 well established skydiving operations & parachute equipment suppliers that sell MC-4 rigs to civilians and in some cases train US civilians in the US on them. The MC-4 maintenance manual notes that it is appropriate both for HALO and HAHO. Is a parachute probibited from civilian use if it CAN be used for high altitude openings, or only if it is SOLELY for high altitude openings? It seems like the FAR might have been written to exclude equipment not designed for lower altitude, lower speed operations. But how low? Or are various groups and jumpers all operating outside the FARs? (...but nobody really cares and the FAA hasn't been looking out for it?)

People need to understand the basics before moving to the more complex stuff, building knowledge upon knowledge, and many have a very hard time visualizing the 'moving block of air' thing in the first place. Otherwise all one can teach is "um, any sort of shit can happen out there, good luck". Which may be true if you get hit by a lee side rotor or whatever you personally might be getting into, but doesn't help anyone understand how to analyze what might happen. The answer to the original question, "Does wind speed and gusts affect descent rate?" is still: 1. No (Wind at any given speed can't, when only talking about wind speed) 2. Yes (Gusts can, whether horizontal or vertical).

I personally see it as something that is theoretically nice, but because of other factors, something one largely ignores in practice. If I jump a rig with a 282 Parafoil, I don't want a huge ass reserve. If I jump a rig with a ground hungry crossbraced 79, there's nothing that small and fast in reserves. And I'd rather have something bigger than a PD 99 reserve (or even PD Optimum 99). So just jump the main you want, and if you have a choice, the reserve size you want. If by some chance the sizes and performance are not too dissimilar, then that's a bit of luck in the rare case of a two out. In your particular case, if you want a bigger reserve, go for it. While someone might say it is bigger than you really need, the extra area is probably more of a benefit that the liability of less compatible canopies -- especially as one tends to see a lot more reserve rides than two outs. I'm not sure off-hand to what degree the rare two-out studies actually tested much in the way of different size combinations of canopies...

To follow on to what Turboprop said -- And we've also had threads about 'when to give the Take Up Bowling' speech, because it is so hard to tell who will perform well vs. perform adequately vs. perform poorly but not dangerously, vs. actually perform dangerously. It can be an issue of what types of errors one will have -- allowing more slower learners through may also allow more idiots through (to be pejorative about it), who may cause more risk to the DZ. With static line, there was more of a sink or swim situation than tandem or even PFF. In the old days, DZ's accepted more risk. There was always some static line student who would screw up. That was part of the fun on the dz, seeing what the newbies would do. ============ As for some actual student mistakes, any one who has been around for a while can come up with a bunch. Easier to just tell the tales than to work out possible corrective measures for instructors: You'd get the students who would have no clue under canopy and sail off into the distance. Very occasionally you'd get the student who nearly killed themself, by things like a low chop. (Some DZ's had actual fatalities do to this.) I've seen one start to cut away up high and then decide not to, leaving the metal SOS handle dangling and landing with 1 cm of cutaway cable through the locking loop. Or the guy with a two out because some old gear unfortunately had a yellow RSL lanyard and he pulled on that instead of the yellow toggle. At one DZ, there were 5 student chops in a day. After one got spooked, a bunch of others got spooked. There's the chopping because "the slider didn't go up", or "the canopy didn't look right -- the colour wasn't the same as in the video. A nearby DZ had the classic "air toggles", where a girl just put her hands in the air and pulled the left or right hand down, just like they did on the ground while practicing steering. (Maybe they didn't have hanging harnesses, I dunno.) Air toggles for air heads! Another student just kept turning the opposite way to the commands, so the instructor just switched Left and Right and got him down safely. A nearby DZ had a near fatality when a student chopped after having already grabbed the toggles, but forgot to let go of them again, leading to a main-reserve entanglement. (Some instructors might miss the step of telling the student what is obvious to a licenced jumper -- If you don't have a mal right away, then do your control check and find a problem, and despite being told to never let go of your toggles, please do so if doing emergency procedures.) You'd get the low turners, the ones who got all flustered on final approach for some reason and did a panic move. I had a girl crank a 180 down low and downwind it between two parked planes. Or there was the girl who turned the radio off under canopy because she didn't like the way the instructors were aggressively talking to her. Very occasionally one gets the advanced student who loses track of altitude and continues down to AAD firing altitude, a little scary for the DZO! There was the student of mine who started to climb out for his first jump with a leg strap unhooked and dangling. I hauled him back in. Straps had been checked before jump run but he must have fiddled with them. There was the advanced student who remembered to turn on the student gear's Vigil, but only on the way up in the plane. She landed under the reserve. Etc.!

C'mon Brian, please please let us know what's on the video, what neat stuff you've been thinking of, what the topic for discussion in this thread might be! Otherwise the post is just an advert... Thanks.

... and the sooner new mistakes will be introduced into the pack job. Although there is something to be said for having different sets of eyes on something. One also gets into a whole discussion of types of errors and their likelihood, whether they are more random (e.g., inadvertently routing something wrong) vs. ongoing (e.g., an old service bulletin missed initially and nobody later expected it to still apply). Fewer repacks might be better if it means people are willing to pay a little extra for a really good inspection; on the other hand, at least here in Canada, I didn't really see any price change when it went 120 to 180 days.

Yeah in the I+R it is almost more about the Inspection than the Repack. Check for loop wear, clean out dirt, that sort of thing. Heck if you're a rigger and not quite following rules for yourself, just open it up, look around, and close it up again. In Canada we've had 180 days for longer than the US, and it is pretty much a non-issue in that everyone is used to it now and nobody really discusses the issue, at least among the riggers & jumpers I know. Those who just jump in summer only need one repack a year, and those who will jump all season or travel in winter get two.

My favourite post (well, 2 posts) was some years back when a fellow was describing doing RW and wrote about "reaching" for grips. Some relative newbie trashed him for his stupidity, saying you are never, ever supposed to reach for grips, but to fly to them, duh. The newbie was both unaware of the subtleties of RW, and of who who he was trying to correct: A former Arizona Airspeed member with 10,000+ 23,000+ jumps, Alan Metni Kirk Verner Edit: Yes it was Verner as was just posted. (Can't find the posts right now unfortunately.) http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3409993#3409993 The one about slamming the Incidents moderator was funny too. The guy was wondering why the heck this PhreeZone guy had this bizarre fascination with posting about death and accidents...

Huh? Just looked like a regular mal during a tandem. No evidence of line dump on main or reserve, at least not during viewing the facebook video and trying to freeze it in a few spots. Do you have stills of any line dump, as it seems hard to find? The original mal was line twists and spinning on a tandem. Maybe a tension know somewhere? Risers got quite uneven which may not have helped.

It is a valid point to bring up, one that isn't often thought about. Nevertheless, examination of military documents suggests that the situation is not entirely dire. For example, one US Field Manual on military freefall procedures using the MC-4 notes that the military Cypres is set for 1500 ft (in one mode), and during emergency procedures, to make the cutaway decision (on this RSL equipped rig) by 2000 ft. Another military document on the MC-4 system mentioned the reserve deployment altitude being 2000 to 25000 ft. In my brief search, I didn't see anything specifically about the time or height the reserve deployment was certificated to. These sorts of minimum altitudes are not incompatible with modern sport skydiving, if special care is taken. That may include raising one's civilian AAD altitude, as well as having strict limits on breakoff and deployment altitude (that are actually pretty normal for the noobs these days). So while your warning is valuable, I wouldn't go so far as to say it is 'plain dangerous' to use such gear in the sport environment. Thanks.