markbaur

Oops! These are similes, not metaphors. Simile: a figure of speech comparing two unlike things, usually introduced by like (lips like pedals) or as (as round as bricks). Metaphor: a figure of speech in which a word or phrase literally denoting one kind of of object or idea is used in place of another to suggest a likeness or analogy between them (a door is a jar). My thanks to Noah Webster. Mark Grammar Nazi

Almost forgot this one, and I bet Jerry Bird wishes everyone had: the 1974 Jerry Bird rig. Poynter: "The reserve container is locked with a unique Velcro closure system and may be used with or without a pilot chute." In 1974, Velcro on rigs was all the rage, a valued replacement for snaps and zippers. The Velcro-closed reserve represented the extreme end of Velcro use, and we've been using less and less of the stuff ever since. Mark

There are several possibilities for what you've described. First, you may be seeing one of the natural reactions to anxiety, the fetal position. Other natural reactions are fight-or-flight (which manifests itself as kicking or swimming), and "cat" (looks like someone trying to get down on all fours). Exhortations to "try harder," "arch more," etc., are generally ineffective and may be counterproductive, as they add to anxiety. Often the best solution is to go back to Cat A static line jumps, no PRCP, just work on the relaxed freefall arch. Second, your brother may be trying to get stable face-to-earth, instead of hips-to-wind (which for static line is a more nearly vertical position). This is a conceptual error, based on watching too many skydiving movies, and it occurs in AFF students just as often as static line students. If you stand on the step or hang from the strut, the wind comes from the forward motion of the airplane. In the split second after letting go, the wind continues from the forward motion of the airplane, so the hips should push to the horizon. At the end of the static line, most of the wind still comes from forward throw, so hips should still be pushed more or less to the horizon. Third, the problem may lie in the pull count. "Arch, look, reach, pull" was the most common count for years, and worked okay when the main ripcord was mounted on the main lift web, about where most cut-away handles are located now. With a hip or BOC ripcord, there's nothing to look at, so as others on this thread have pointed out, looking down degrades the arch. A better count is "Arch, reach, pull" or "Arch, reach, feel, pull." (If you want to change, be sure you discuss it with your instructors first -- they may have years of success with "Arch, look, reach, pull" and have better reasons for keeping it than I have for changing it.) In fairness to your brother, the hardest jump in skydiving is the static line PRCT. With just seconds of "freefall" time (the length of the static line, times 2), a student is expected to maintain stability at subterminal while pulling a ripcord within 4 seconds, but trying to pull too quickly results in haphazard grabs at the ripcord, and pulling too slowly makes it difficult for the jumpmaster to tell if the poor arch was caused by the student or by the opening canopy. Mark

Could you describe these four different sets of hand signals, please? Mark

There was a time when the 3-ring release was not standard, but innovative. I don't think I suggested four completely different sets of hand signals. If you can adapt to the (non-standard) 3-finger PRCT signal, you can probably adapt to the fist for pull. Your "learning to drive" analogy breaks down when you consider that we don't need to teach a student to drive a bunch of different cars, just one car, and one not much different from the one the last instructor rode in. Here are some experiments perpetrated on students: -- AFF -- square mains -- radio How would you have kept these experiments separate from training at large? Mark

More interesting gear ideas (from Rodriguez Parachute Systems' Spanish Fly): -- Instead of a steel cable reserve ripcord, use suspension line, with a pull-out style closing pin. Passed the FAA 300-pound pull test, so why not? -- "Web-lok" hardware instead of friction adapters for chest strap and leg straps. The webbing was doubled, and a freely-moving stiffener was sewn inside. To adjust the harness, you'd pull the strap tight, then push the stiffener to the fold in the strap, where it would act as an internal friction adapter. Poynter: "The web-loks were not accepted by the industry." How about this: If you rotate a round parachute (like a horizontal pin-wheel), you can increase the stability -- no oscillations. That would make the jumper dizzy, though, wouldn't it? So add a swivel attachment at the base of the lines, above the jumper's head. Ummmm... Dan Poynter found that there is some residual friction in the best swivel adapter, so the first test jump (into water, wisely), was also the last. Or this: Stewart Systems popularized the loop-style cutaway handle, and I recently saw a rig (not a Sweethog) with a similar loop-style reserve ripcord handle, which combines the best attributes of a conventional metal handle (better grip when you put your thumb through the look) and a soft handle (less likely to snag). Unfortunately, it lack an important feature: slack in the ripcord cable. Stretch the harness, open the reserve. Mark

I don't think you're suggesting that anyone deploy at 350kts. Are you saying that blast handles are less likely than D-handles or Martin-Bakers to be pulled accidentally, by wind, snag, or user? Mark

Greene Star Systems, Xenia, Ohio. Closed its doors in 1979, as a result of loss of business and lawsuits related to the riser separation issue. Mark

Why do you think that is? Mark

Not quite. The mistake was sewing through the comfort pads to attach the risers to the harness. The risers failed because folks picked the stitches to remove the pads -- to save a few ounces of weight -- without checking to see if the stitches were structural. No fix was necessary for the folks who didn't try jumping partially disassembled harnesses. Some jumpers may have added a confluence wrap, but it's hard for me to imagine a deployment scenario where the stitch pattern is subject to catastrophic peel and not sheer. Mark

For the unitiated, the goal was to get line stretch before canopy inflation. The Reuter wrap was a piece of (1"? Type 4/square weave?) tape which wrapped around the lines at the base of a round canopy. One of the suspension lines had a straight closing pin (like the kind used on a pull-out) sewn to it, and the line had to be drawn up to insert the pin in a channel at the end of the tape. The idea was that at line stretch, the pin would pull down out of the channel, release the wrap, and allow inflation to begin. The concept is not much different than with a 2-bight diaper, which uses half the lines to lock the diaper, pulling the bights out at line stretch. The Reuter wrap was not in production very long before Pioneer switched to 2-bight diapers. Another wrapping "deployment sequencer" was the OSI, Opening Shock Inhibiter, used to stage the deployment of a Rogallo-type parachute, the Parawing. The OSI was a strip of fabric about 6" x 60". Packing required wrapping the OSI around one set of colored lines, then including a set of different colored lines in the next turn, and repeating the process until all the lines were wrapped up. When the canopy came out, the lines would theoretically be released in sequence until the parachute was open entirely. Later Rogallo-types (like the Paradactyl) used sliders. Mark

Oops! Hydraulic reefing was just that, a mechanical device (fluid, piston, cylinder, etc.) used to gradually release the lines. Ropes-and rings came in two flavors. The original version was on the top surface of the canopy: rings all around the edge, rope through the rings, runs to the base of the pilot chute. Pack the parachute, all the rings are near each other, makes a really loooong pilot chute bridle. Open the parachute, pilot chute retracts! However, upper-surface ropes-n-rings requires reinforcing to carry the loads through to the suspension lines. Lower-surface ropes-n-rings was similar to upper surface, but the bridle passed through a vertical cotton (so no nylon-to-nylon burns) channel from bottom to top to attach the base of the pilot chute. The idea of using the pilot chute itself (rather than the slider) to provide the drag to stage openings continues in some ParaFoil accuracy canopies, where the pilot chute is attached to an X-shaped slider which retracts the pilot chute as it descends down the lines during opening. Mark

Most round canopies in use today use diapers to hold the skirt of the canopy closed until line stretch, and the Raeper did the equivalent for squares. The 3-stow version was the most popular, but a few folks also used just a piece of webbing with a single grommet. One line stow was enough to keep the strap closed. These systems are used without a bag; the canopy is "free packed" in the container (which looks scary but is no worse than what's going on inside most main bags), allowing the canopy to fill the corners, giving a more pleasing shape and making for an easy close. Most folks quit free-packing when they found they could half-hitch their lines around their main container flaps. The solution to that was stowing the lines on the diaper or bag, so they're lifted away from the container in an orderly fashion. It's possible to stow your lines on a diaper, but it makes a big mass that's hard to pack into the container. Ugly = out-of-fashion, so no diapers any more. Interestingly, the Pioneer X210R had a tail-mounted full diaper. I believe it was the only square reserve TSO'd without a free bag. Mark

Jesus strap: Suppose you pulled your reserve ripcord, but the container didn't open because the closing loop was caught on a grommet? This isn't very likely on the gear we use now, but it was more likely on the gear used in the late 70's. The difference is that then instead of using fabric closing loops, we used military-surplus metal cones (about 1" diameter base, 1" high) with a ripcord hole drilled through parallel to the base. Much more durable, don't have to worry about loop fraying. Unfortunately, the hole could develop a burr, which could catch on a flap grommet, preventing the container from opening. When the reserve was mounted on your belly, this wasn't a big problem, because you could just reach down to manually open the flaps, but with a back-mounted reserve, you can't reach around to do that. The Jesus strap (last-hope rope, etc.) was a piece of suspension line attached to a flap of the reserve container, routed over your shoulder, and attached to the reserve ripcord. When you pulled the ripcord, you also pulled the container open. Unfortunately, if you dropped the ripcord, it would sometimes entangle with the reserve. --------- Gravel plug: When dinosaurs walked the earth, skydivers did a lot of PLFs, and sometimes got dirt and gravel inside the ripcord housing. Gravel plugs were donut-shaped plastic inserts for the end of the ripcord housing, intended to let the ripcord move, but keep dirt out. However, making the housing narrower made it more likely that any dirt that did get in would jam the ripcord. Annoying if it's your main ripcord, and really annoying if it's your reserve. ------ Hydraulic reefing. Tried jumping your parachute with the slider packed at the links? The original squares came without sliders, and there were a number of experiments done to try to get the openings slow enough to be tolerable. The Volplane's hydraulic reefing system was one such idea. It could be adjusted for the speed, so before you packed, you could set it for a slower opening (terminal freefall) or faster (hop-n-pop). However, if you changed your mind after you packed, you could get a really snappy opening (set for hop-n-pop, but taken to terminal), or a very, very long snivel (set for terminal, used for hop-n-pop). Later versions of the Volplane were equipped with sliders. Mark

Pulling down the apex of the canopy is a way to increase the projected (open) diameter, one reason why a 24' Para Commander has the descent rate of a much bigger conventional round. However, you have to add crown lines for the pilot chute attachment, and without other modifications, openings are inconsistent (at best!) and the canopy is quite unstable. With practice, it's possible to consistently stand up a cheapo in light winds, so the lower descent rate isn't necessary. Sounds like a fun experiment, though. On a cheapo, the lines are continuous from link to canopy skirt, inside the radial seam, over the apex, and down through the opposite radial seam to far link. The lines are sewn to the canopy skirt and to the lateral band at the apex, but are free inside the radial seam, allowing the canopy to absorb severe opening forces without damage -- and in their original application as military reserves, deployed canopy first (canopy opens, then you fall to the end of the lines), opening forces could be quite high. Removing the lines from inside the radial seam was a common way to reduce pack volume, while keeping sufficent strength for civilians using canopy sleeves or bags. Since many cheapos were packed in converted military rigs, the reduced canopy pack volume compensated nicely for the volume of sleeves or bags which the military containers were not designed to include. I have not heard of gutting the suspension lines themselves, and I think this would be a laborious task since it would involve replacing all the lines on the canopy. Mark

None of these were really inherently bad ideas the way that Jesus straps and gravel plugs were. They were simply state-of-the-art at a time when the art was in its infancy. Mark

If you attach your pull-out handle to the nose of your free-packed main, you can dispense with the pilot chute altogether. Mark

Actually, I think we disagree. If you teach "thumbs up" as a pull signal, sometimes students will pull when you give "thumbs up" and sometimes students will continue skydiving because you've used a signal which for their entire pre-skydiving experience has meant "you're doing great!" Can you see the parallel argument about using a pointing gesture to mean something radically different than the common meaning? Mark

Not yet. Standardization inhibits innovation. We don't need standardization between DZs, since we discourage students from DZ-hopping, and instructors are savvy enough to adapt to the students' signal set. We need to continue experimenting to see what works: more hand signals (for greater variety of info transmitted), fewer (less complexity), different (looking for better, more intuitive transfer of information). Mark

Perhaps your experience is different than mine. Under stress, most folks revert to previous training. Twenty or thirty years of previous training for the one-finger signal is "look at that!" And if you tell a student that "thumbs up" means "pull" you run a very high risk of them thinking this freefall stuff is swimmingly fine when what you want is an end to the freefall. What we need is a set of signals that builds from known (previous non-skydiving experience) to unknown (what the signal means in freefall). The initial signal set should be small, to reduce the amount of decoding a first jump student needs to do, although additional signals (like "toe taps") might be added on later jumps. Most first jump students would do just fine knowing only three hand signals (hips down, extend legs, pull), plus alti tap. We can fix the arms and wide legs on the next jump if we need to, when the student is more responsive. Related actions should have related signals. We already have that with "extend legs" and "bend knees." We could have that with open palm for "touch ripcord" and fist for "grab ripcord." Mark

At Skydive Twin Cities we're using a fist as a pull signal, figuring, as you guessed, that it's easier to teach that than to break a life-long habit of interpreting pointing as "look over there." In the transition from pointing to fist, we learned to ask our students, "If I wanted you to pull your ripcord, what signal would I give you?" Using a fist means that the standard PRCT signal is not available -- others have already pointed out that the two signals are too similar. We've done without a PRCT signal this season. Some instructors here think we need a PRCT signal, so we might use one next season (open palm, for touch, as an analog to closed fist for grab), but the trade-off is signal clutter -- another signal for an overloaded student to remember. I know some places use three fingers to indicate 3 PRCTs. I think that requires a lot of decoding by a student under stress: 1 finger = pull, 2 fingers = legs out, 3 fingers = PRCT. Plus, what do you do if you want just one more PRCT? Mark

I have a bunch of PC jumps, and I stood up most of them without using toggle or riser flare. Pulling down toggles or risers does reduce the forward speed, allowing a more vertical descent -- a good accuracy technique if you arrive at the target a little high and with extra speed (typical for hard-core accuracy competitors making downwind landings) and are willing to accept a higher descent rate. Mark

When you pull down on the rear risers of a round parachute, you increase the descent rate. When you release the risers, your descent rate returns to what it was before. There may be some miniscule rebound effect like a yo-yo at the end of a string, and if your timing was exquisite you'd be landing while the rebound was up, but you're just as likely to land while the yo-yo is headed back down. What makes landing a round hard is the same thing that makes landing a square hard. Your experience is with accelerating falls; you don't have much experience with constant-speed falls. The folks who have perfected the riser-snapping techniques have just made more constant-speed falls, and if they had done the same number of jumps trying stand-ups without riser flares, they'd have done just fine. Mark

Based on my experience with about 1000 jumps on a PD-210 loaded at about 1.1, if you use toggles to collapse your PD-190 loaded at 1.1, the worst that will happen when you let up quickly is a line twist, and even that is unlikely. (Line twists on highly-loaded canopies are much more likely, and much more serious, though.) The canopy will surge forward when it starts flying again, but you can reduce the surge by letting up slowly. The canopy will not streamer or turn into a "wad of crap." You might be able to pull down far enough that the ends of the tail meet, creating what looks like a line-over or bowtie -- safe, but scares the heck out of people watching. Actually, it's kind of fun to find out exactly where the stall point is so you can fly right on the edge: toggles up a couple inches to fly, toggles down a couple inches to stall. Mark

The manufacturer (that would be you, if you were the one putting the clotheslines on the bedsheet), can alter or make modifications to the main parachute, without needing a master rigger ticket or TSO. Mark