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. )
