pchapman

Another bit of media to show, this time it is a clip from an amateur Russian video of packing a D-6 rig. (Not my rig.) Not many will want to bother clicking through, but it shows the way the canopy is literally stuffed in the bag, the top of which is closed with a draw string. Bizarre! It's on my video page: http://pcxstuff.blip.tv/file/3721483

EFS4LIFE indeed didn't pay much attention to those points. I wonder though, to what degree the Germain charts takes into account low wing loading ellipticals. That may be a situation outside of the main design range of the charts. And if one wanted to take what experienced canopy designers say as gospel, then one could pit Brian Germain against John LeBlanc. EFS4LIFE at 1:1 under a Stiletto 190 is only marginally outside the recommended range for a Novice under a Stiletto 190. (Max 181 lbs) And we've already seen how a large proportion of traditional Stiletto jumpers have been outside of PD's recommended range. This makes any transgression of their suggestions seem less of a problem. As for the ability argument, someone could be average in inherent ability but be given superior training, and thus become above average in skill for the number of jumps. Sure I'll jump on the bandwagon and roll my eyes at the typical over aggressive and self-confident newbie. On the other hand, despite my much greater experience, EFS4LIFE still has a bunch of jumps on a Stiletto 190 at 1:1, something I've never done. So despite his lack of experience from which to base his comments, it was interesting to see what he said about the canopy.

Thank you. When you have time it would be interesting to see! (I have a Slovakian manual, but even with the drawings in it and Google Translation, it isn't clear what the issue is.)

Hi Nelyubin: Any hint on what is wrong in photo #2? Remember that it is a little odd looking since it is a belly mount container for a 3rd canopy. and there were no line stow loops on the backpad. Yes, the bottom of the canopy was at the top of the container, not the bottom, so that was reversed. But that is trivial.

Fair enough, but I will say that not everything in the PD wing loading charts is to be taken as gospel. Look at the Stiletto 120 for example, the canopy that seemed to be the most common for any experienced jumper in the mid 1990s. Taking the PD chart, and allowing 25 lbs for gear, we'd expect that the typical experienced jumper, in the Advanced category, would be 119 lbs or below. Or 143 lbs or below for the real Experts. I don't recall the skies being full of 110 lb jumpers on their Stiletto 120s...

I haven't thought everything through, but it seems a bunch of unusual things had to happen all together. (Yeah, that's how accidents can occur...) 1. The seal thread had to go through (not around) the closing loop. That could be accidental, even if unusual. While one should be able to see the routing, I could envision that someone without 20/20 vision might miss something unexpected. 2. Then when the ripcord pulled it had to break the thread 'above' the seal, where it connects to the ripcord, rather than breaking it 'below', where it went around the closing loop. That lower loop needed to be intact to allow the closing loop and seal to stay connected. Fifty fifty chance? Or was the thread somehow poorly wrapped on the ripcord, sliding off? I'm not sure how to interpret the photos: Was the thread 'above' the seal still a continuous loop, or 2 broken pieces? At one point, it almost looks like a knot there, which normally doesn't exist. 3. As the pin is pulled from the closing loop, somehow the seal thread doesn't break as the slack is taken up and the seal slams into and stops in the grommet. I'd think if the seal were very close to the grommet to start with, it would reduce how much the pack could start to open before the seal hit the grommet. Assuming it was proper seal thread, a decent pilot chute should put quite a bit of pressure on the thread - normally a lot more than 2 * 4.75 lbs = 9.5 lbs. It has been a while since I packed an Atom so I can't recall how their pilot chute strength is relative to other rigs. (E.g., on a scale of Javelin to Mirage pilot chute in strength.) Generally, it is unlikely that the thread would hold. But that's the way it seems to have happened. If there were some zig zagging of the closing loop plus seal thread through grommets, that could reduce the pressure needed to hold the rig closed. The zig zagging creates a pulley effect. For example: While using a Cypres Spectra pull-up cord to close a reserve container, if one holds the cord flat against the rig, 90 degrees from the direction of the closing loop, it can be easy to hold the container shut with under 5 lbs of force. I've attached screen captures of bits of the video from YouTube to make it easier to see the situation.

+1 on most of what councilman24 says The topic has come up in the forums before and Mel just got clarification. Maybe we need a new thread to bitch about what many of us consider stupid FAA rules. Given what councilman24 said about the interpretation many experienced riggers had, does the USPA or PIA have any plan in place to try to get the FAA to change its mind on who can pack main parachutes and work on mains?

Sarcastic DZ.com response: You have 900 jumps and haven't seen this yet?! Normal response: Unless I misinterpreted something, that's a very commonly used idea. Except you don't actually need a fancy barb. Almost any sort of webbing lump on the riser (not far above where the risers split) keeps the grommets, pulling at an angle, from rising up. And front risers only is oftenenough. The problem is that even if the slider is kept down, and has kill lines in it, it can still billow up somewhat in place and catch air. E.g., I use the kill lines in my slider to reduce its area; I use the couple small lumps of webbing I sewed on my front risers to keep the slider down, but I still spend the time to twist it a few times so it doesn't catch air, flap around, and catch the back of my head.

FWIW, there is a torrent on TPB ('the Swedish site') of the Racer reserve packing DVD, deinterlaced, compressed to mp4, and saved into individual chapters from the original 40 minute video. It looks like there's just one slow, occasional seed so the ball isn't rolling at the moment so to speak, but it eventually could be. I already have a physical copy of the DVD off a Racer enthusiast. Free access to the video would surely benefit any rigger wishing to pack them -- and Jump Shack too.

Racers are a bit bizarre -- and you'd think a smaller company would try harder to be user friendly. 1. You get a manual that says it only applies to the rig it came with. At least they are clear about that. But how do you find the right version for a particular rig? Their web site only shows the current version. 2. The current manual (2003) says all rigs after 1997 come with a Spectra Quick Loop. But then the manual goes on about Kevlar Quick Loops. 3. There's the bizarre ancient rite like some 1950s military rig, of optionally tacking through the Kevlar loop to prevent fabric from getting in the loops. 4. If the Quick Loop is a TSOd part that can't be built by the average rigger like on almost any other rig, why doesn't the manual make that clear? 5. The manual does not mention the big difference in opinion between Jump Shack and Airtec on reserve loops. Airtec has the sewn, free running loop but says that in the USA due to TSO requirements one must follow the rig manufacturer's instructions -- which would be Jump Shack's adjustable, tacked down loop. 6. To replace the loop you have to tack it to the pilot chute, and then tack the pilot chute cap in multiple places. Other rigs like Teardrops, Reflexes, and even Wings have figured out easier ways to attach a cap to a pilot chute. No wonder a new rigger gets confused.

Here in southern Ontario I find almost riggers write down the pull force. It seems to be tradition, and there was a column for it on the old style paper CSPA data cards. Most pack jobs that I see from the USA though, don't show pull force. I haven't checked the FAA regs but I got the impression the pull force has to be measured to be in limits -- but nothing says it has to be written down for the user. Can someone confirm? There are a lot of variables for pull force, but it can be handy to get an idea of what the pack job is like, whether it is really tight or more moderate, whether it might be worth tightening the loop a little. Some of that of course can be determined by looking at the rig too. I think a little fudging is sometimes indulged in -- I can't imagine that some of those tight rigs really are at 22 lbs max at the time the pin is inserted. Maybe a couple days later.

One more photo - This shows the D-6 canopy in flight from below. It better shows how the canopy is something of a "square shaped round".

LOL, Nick nails it on the head again! But seriously, I also got the impression from the NTSB report that the stall training they did at Colgan was so "mild" that it reinforced the wrong behaviour, whether in the sim or in the air. It sounds like a bit of an industry standard too. The pilots got so used to having to fly out of an incipient stall with minimal altitude loss, or fail the evaluation. Therefore entirely wrong behaviour had been reinforced, when they actually had to deal with a real stall where you couldn't just power out of the problem and pull out immediately. The subject is obviously complex so a short post can't do the topic justice. And on that particular flight there may have been other misperceptions on the part of the pilots -- the whole icing and tailplane stall thing. Here are a couple quotes from the NTSB report showing the issue I'm talking about: From one of the practice stall profiles (my emphasis): From the main text:

Neat idea. I didn't recall it but was curious enough to search. It is mentioned in these threads: http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3471481; and http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3047008 A couple more minor points about my D-6 jumps: 1. There is no TSO requirement in Canada so it was legal to jump. (To use more historical equipment in the USA, I guess you'd need something in skydiving akin to the Experimental Exhibition category for airplanes. That reg allows otherwise uncertified airplanes to be used in the US although only under very specific conditions. To simplify a little, it is good for displaying aircraft at airshows but not for general personal or business use.) 2. I've got something Beatnik hasn't jumped.

On the weekend I made a couple jumps on a Russian paratrooper rig that I acquired, one of the type with a static lined drogue. One freefalls with the drogue, then pulls a ripcord to release it to deploy the main. The D-6 isn't the latest Russian design, but one that was long used, and is still available new. The short version is that everything went well. The long version is everything below. Main: D-6 series 4 Reserve: Z-5 I'm not quite clear on what the system as a whole is called, but since all the parts are integrated to work together I think one can call the whole assembly a D-6 or D-6/Z-5 system. I might be the only kid on the block locally with one of those -- although many many Eastern Bloc military jumpers will have jumped them. It's a fore and aft system, with round canopies that are partially "built square", with reinforcements at right angles like a tic tac toe board, rather that radially from the apex. The main is essentially unvented, so movement is by sideslipping only. The reserve is a belly mount with no pilot chute. The jumps were likely the very first on that rig, because there's absolutely no wear on it. Basically I understand it went into the military system, sat on a shelf unused (since WWIII didn’t break out), and after 12 - 15 years or so the official life-time was over and it got sold off surplus. One cool thing about Russian rigs is how their designs are so different from what we're used to from the US. Something which is a fundamental philosophy in the US, like applying tension when packing a main or reserve round canopy, may not be so in Russia. At the top of the rig there's a drogue in a pouch with a static line hook on it, held to the top of the rig with a bungee until hooked up in the aircraft (I added a temporary extension so I could static line from a C-182). The idea is that the drogue is deployed on exit, the jumper drogue falls for a while, then pulls a ripcord to release the drogue to deploy the main. Alternatively, a KAP-3 or similar AAD can release the drogue. I don't know much about military airborne operations, and I used to think the drogue was about allowing paratroops without freefall training do freefalls. Whether or not there is some truth to that, I now understand that the main idea is different: The D-6 allows jumps from up to 250 mph, such as from jet transports -- with the drogue slowing the jumper down to a tolerable opening speed, without using a particularly heavily built canopy, and allowing a nice deployment configuration (rather than getting the 'whipped from the side' effect of the traditional static line round canopy deployment). Minimum quoted jump height is 500 ft, with a 2 second delay from drogue deployment to release. (I've converted all the Metric numbers to Imperial) One of the photos, taken from the web, shows a bunch of Russian jumpers in short duration drogue-fall behind a jet transport. Another is a tiny photo off the web of a jumper with drogue just deployed out the door of an An-2, to provide more scale for the drogue system. D-6 droguefall is novel, as once one is off the hill, one is pretty much hanging in a slight sitting position from about the nape of one's neck, with the relative wind coming from below. I could spin myself around under the drogue by doing exaggerated mantis style turns with my arms. On one jump I exited at 5000' and drogue fell to 3000' before pulling the ripcord. The opening was about as soft as doing a hop and pop with a round like a Paracommander. One Russian told me the drogue fall speed is quoted at 35 m/s or 78 mph, but that's likely for a heavy weight situation, so I may have been going somewhat slower. The D-6 canopy is 83 m sq, or 890 ft sq, which is equivalent to a flat circular design of 34 ft diameter. Max rated load is 310 lbs, with a descent rate of under 5 m/s or 16.5 fps at 265 lbs -- So for a light weight jumper like me the landing is pretty soft in low wind. For me on opening the canopy did 'jellyfish' somewhat, from the wake recontacting the lightly loaded canopy. Turns are made with a red loop of cord on either side, that runs between front and rear risers, with lines that travel up to the small slits right at the front and rear of the canopy. This is quite a different steering mechanism than on western rounds. Turns are very slow, for me at light weight maybe even slower than the specifications saying about 20 seconds for a 360 turn. I jumped on a day of light winds. While one jump ended up a couple fields from the DZ, on the next it was nice to land within 100 m of the beer line, front and centre. Landings were lightly rolled out. See the photos to help explain things described here. The rig: The harness has sling saddle and various adjustments quite unlike sport rigs. The hooks on the leg and chest straps look rather insubstantial. One leg strap has the hook on the leg strap, while the other has it on the harness end. That seems odd but it removes any confusion over which is the right vs. left one. The belly mount attaches the usual Russian way. Instead of snaps on the reserve risers hooking to D rings, the harness hardware has a sort of wide clevis. A loop of the reserve risers (sometimes with a plastic tube insert) fits into the clevis, and a long pin slides in, and locks with a quarter turn. Spring clips are inserted as safeties to avoid any inadvertent push and turn of the pin. All the Russian webbing has a 'less tight' look to it, making it look more like cheap old cotton camping equipment for someone used to the really tight, flat surfaced weaves of American MILSPEC webbing. There are no 3-rings, Capewells, or similar. There is a release mechanism on one side only, to release one set of risers if being dragged on the ground. Pulling a webbing tab pulls open a cover, that pulls a pin, that allows a couple wraps of thin webbing around metal bars to unwrap. Once that unwraps (sort of like the old Strong Wrap release), the right set of risers come free. From the back, the main container looks a bit like a cotton knapsack. The pack is held closed at the top by a couple of tabs of the drogue release mechanism through rings. Other that that, there's nothing holding the pack closed. The entire back of the pack stays closed simply by the two flaps overlapping each other. Ingenious. The pack has a metal frame in it at the back pad area, which also gives rigidity to the whole drogue release mechanism behind a flap just behind one's shoulders. There is a rotary disc mechanism that allows for drogue release. In the photo, the two straps at the sides lock onto big pins in the mechanism. From there the straps travel through an opening in the pack frame (taking some of the load in drogue fall), and then they attach (out of sight in the photo) to the drogue bridle. The disc mechanism can be turned by ripcord (at the top), or by AAD (at the bottom -- none present in the photo). Apparently if you needed it, your kit bag would hang behind your thighs, and your folding stock AK-47 style assault rifle would be wedged in between you and your belly mount. While guys with Eastern Bloc military experience tell me that that can be a bit of a hazard for hitting your chin on, at least you can theoretically start firing at things while on the way down. Keeps the whuffos out of the landing area. The photo of me coming in for landing shows how extremely long the lines are, more than on a ParaCommander. Another photo shows the canopy in more detail with the combination of square pattern reinforcement tapes plus some diagonal tapes. The drogue photo shows a fairly complex drogue system that seems to work but isn't as clean as say an American tandem drogue. Not something that one would want to hand deploy instead of static lining; too many snag points. (The belly mount reserve next to the drogue in the photo helps give it some scale.) Packing the rig is particularly interesting. I can't be sure this is the official method, but it is what was taught to me by the Latvian / Russian jumper who got me the rig. Some coloured marks on certain lines help identify key lines to start and end with. When packing, the rig is weighted down like when doing a normal ram air pack job, but unlike western rounds, no tension is applied to the apex. The canopy is flaked but because there are no radial tapes, the whole thing is a little messier. The canopy is loosely folded lengthwise in thirds. The 'bag' for the canopy is the length of the backpack. It isn't packed like a bag though, for it slides down over the canopy like a sleeve until one reaches the bottom of the canopy. Most of the canopy is sticking out the top of the bag. One takes a couple feet of the canopy at a time and stuffs it down the length of the bag, bottom to top of canopy. Although one is trying to create layers of folded canopy, one is literally grabbing the canopy and stuffing it into the bag. The top of the bag is then closed with a drawstring that is given a simple knot -- exactly like closing a stuff sack! Four bungees and grommets are used to close the bottom of the bag, with lines going side to side on the outside of the bag in a fairly conventional way. The rest of the long lines stow in foot long light fabric tubes, running up and down the bag. This takes a special forked tool to push the lines in all the way, or else some jury rigging of other techniques. In the photo with the empty d-bag, one can see the bottom of the drogue bridle above the bag. Two white pieces of webbing with the circular lugs are the ones hook into the drogue release disc. With the d-bag inside the container, the webbing goes through grommets in the two container flaps, through the gaps in the metal pack frame, and into the drogue release mechanism. The drogue bridle folds up with the drogue stuffed into a small pouch with break cord holding it closed. The Z-5 reserve is of similar construction to the main, but smaller and with shorter lines. It is rated for a bunch of uses in the military in case of partial mals of the main, but only one use if the jumper has no main out at all. If under a partial mal one hand deploys the reserve in the conventional way, but with a total mal (only drogue out) one just pulls the ripcord. There's no pilot chute, but on top of the reserve there is cap with cupped vents on it, of less permeable fabric. There's no photo here, but it is like the orange cap seen on the drogue. I believe that on the reserve this both catches air (helping pull the apex of the canopy out like with a pilot chute), and forces air into the top of the canopy (to help begin the filling process). Neat. Overall it was an interesting system to jump, but not very practical at the average DZ because of the difficult in spotting for a canopy with near zero forward speed capability. I have seen only bits and pieces about the D-6 on the web. For video of others jumping such rigs in the world, these are a couple acceptable videos I found: AN-2 exits:http://www.youtube.com/watch?v=AzWxq2g0rqA&feature=related Jet transport exits, low resolution, on a D-6 or very similar:http://www.youtube.com/watch?v=xvJ_fehZy_E (I don't have any packing manuals, and without knowing Russian, I can't even do an effective search for them. So I'm interested if anyone can find manuals. )

I finally jumped a PZ-81 this past weekend. Beatnik has covered the canopy well, but I can add a few pics. #1 shows the canopy while being packed. It is side packed, nose on bottom, tail on top, but after stacking, fabric is pulled outwards to make it flaked to both sides instead of all to one side. Four little pockets on the trailing edge must help pull the tail outwards during inflation. There's no rolling or wrapping of the pack job from the state shown in the photo. Just push the sides inward to match the container. #2 shows the canopy starting to go into the pack tray. Lines are stowed in the packing tray and the bottom most part of the canopy plus a couple folds of lines are wrapped with elastics to at least keep the deployment a little bit organized, given that there's no bag. (3 regular elastics, cut in half lengthwise, double wrapped, according to the eastern European guy who helped me out) #3 shows a landing. The one steering line per side just feeds into the suspension line going to the back corner of the canopy, about half way up. This is different from say Paradactyls where there are more normal steering lines cascading to cover parts of the trailing edge. (On landing I did try a flare although it isn't recommended. Even a short flare did seem to increase the rate of descent.) The canopy does fly nicely, with a lot of toggle range and no sign of instability or sudden stall, although I didn't push it to the stalling point. The PZ-81 is quoted at 290 sq ft, compared to a single keel Paradactyl at 240.

The whole point is that the new style pullups are better than type III, which are better than gutted 550. Skydiving companies traditionally have type III binding tape around, which has long been the standard. If one walks into a sewing related store, it is hard to find any tape that is not really wimpy and weak, that will break too easily. A few companies (eg LookMa, UPT, Airtec) have found other sources for strong but soft on the hands pullup cords. It isn't exactly the most exciting innovation in our sport, but I'd say type III tape pullup cords are no longer the state of the art. At least no country has yet made the new designs mandatory.

Yeah, the notion of a "wall" or "barrier" at Mach 1 is a bit of a myth, that comes from the simplistic way that it has been historically described. It was a barrier of sorts, but the words used in English don't help provide real understanding about it. Are there big differences in air foil aerodynamics that make it tough if you haven't designed your plane for transonic flight? Yes. Which resulted in loss of control and crashes. Is there ever more rapidly increasing drag as speed goes up? Yeah, just like normal when going faster and faster. That was a problem for aircraft back when they were underpowered for the needs of transonic flight. And if one is thinking about "the massive forces on the body when trying to go that fast": The dynamic pressure at terminal velocity still has to equal the jumper's weight. Let's say some stratospheric jumper with all their gear weighs 300 lbs. If on a normal skydive that puts them at 150 mph (to pick a number), then at terminal velocity way up high the pressure forces on the body are going to be the same 150 mph basically -- even if the guy is going 700 mph true air speed. (Similarly, that an airliner might have a red line at 280 kts -- yet fly at 600 mph up high -- because the pressure of the less dense air being hit is still less than that 280 kt red line at sea level. (Mach number limits are a separate matter.) So, at a first level of approximation, the jumper isn't going to feel anything much different. Waving his hands in the breeze would still feel like 150 mph. That's a pretty disappointing barrier; the jumper probably wouldn't even know he crossed it until the data were analyzed on the ground. Let's check actual air density up high: At 60000', for just one example, the air density is about one tenth that at the surface. The basic equation for dynamic pressure means to get the same pressure force from movement, you have to be going 3.2 times faster. So if terminal for the jumper down low is 150 mph, it'll be 480 mph at 60,000'. Sounds like if you want to break Mach 1 on your belly, you might expect only to do it much higher up in the jump. Calvin 19 wrote: I'm not sure about that breaking Mach 1 in freefall thing?? I don't recall the exact conclusions from all the Joe Kittinger threads, but I thought there were some data that was just wrong (eg, reports with a typo of 718 mph not 618 or something like that), while the other data (618 mph at whatever altitude) didn't seem to make sense as being above Mach 1 when the numbers were worked out. Close, but nothing to clearly show he had actually done it. Plus I'd want to know more about the accuracy of the speed measurements. But that's just off the top of my head. [edited a bunch for clarity]

I like the idea of having both the original and the convenient streamed Flash video available on a site. With the appropriate browser add-ins, I can download Flash videos from most websites, and if a site were designed to easily allow downloads, that would work even better. I put some of my videos on a video site (blip.tv) where one can watch (and thus download with the right software) either the flash conversion, or the original high quality video. I did like the way skydivingmovies tried to make people provide detailed descriptions in various categories, for every movie uploaded. A good description is in a sense far better than even Flash -- it makes it easy to look through lists and search for certain content, without even having to download Flash videos and see what you got. There was a certain technical quality and intellectual honesty of having detailed descriptions, that made skydivingmovies a real resource.

Precision 365 openings? Terrible from my point of view -- they shake and snap and whip you around on opening. But that is from someone with only maybe 20 jumps on them, who normally jumps Sigmas, which have a relatively smooth opening. Keep that very limited frame of reference in mind.

L/F = Lite Flite??

While internet diagnosis is tricky, and I'm no expert RW coach, I get the impression that maybe your upper legs are angled downwards from the hips, because you can't flex well at the hips. Generally, the more one spreads one's legs, the less one can arch at the hips. So it can help to bring the legs more together to be able to arch better. Except as a beginner one doesn't normally need a really wide spread eagled position to stay stable in the roll axis. How else to counter backsliding? A jumpsuit with big booties could help to drive more with the lower legs. Or even angling the forearms down when in the box position to counter backsliding. (Normally that isn't something that is done because the legs can handle forward movement better.)

Yes, coveralls. Most are new, but some are indeed bought used. And of the orange ones, there's a popular one with D.O.C. (Department of Corrections) on the back.

From an upwind jump run? (In which case every turn is downwind.) So then one then gets into whether the canopy has time to turn past downwind yet stops at that point. (Maybe yes from 3000', maybe no from 500'.). So if one wanted the canopy to fly straight, one would just do a downwind jump run? (One might also have to deal with issues of wind direction changing with altitude, but in many situations it wouldn't be large.) Signed, skeptical but interested.

One DZ: Coveralls optional, depending on temperature, clothing, and students' preference. Another DZ: Coveralls mandatory. (This is Ontario; it might be less workable in places with much longer periods of high temperatures.)