pchapman

Nice way of looking at it!

According to Christian tradition, do you have to ask a Jewish friend to put it up? (or Italian??)

The sometimes argumentative Beatnik did indeed set a record, given that the CSPA divided its "most jumps" record into Round and Square. Thus there is in Canada: H-1B Most jumps done in a 24 hour period - Square Jim Wilson, Aug 19, 2009, Westlock AB, 202 jumps Not close to the world record but still pretty damn good locally. Both curious and impressive is that the Round record is Jean Pierre Blanchet's from 1972 at 232!

How about student operations? They don't always buy new gear and may stay conservative about procedures. Thus did they go to pilot chute reserves and cutting away?

This is something I always wondered about and never got clear answers on. In the older old days, one didn't cutaway in response to a mal but hand deployed the belly mount reserve. Eventually, along came 'high performance' rounds like the ParaCommander, that with their many slots, could spin quickly during a mal, making manual reserve deployment riskier. Was manual reserve deployment considered acceptable or not with ParaCommanders? Was it something that people did initially but later decided was not acceptable, that one must cutaway (e.g with 1 1/2 shots) and use a reserve with a pilot chute? Was there a difference in what students were taught vs. experience jumpers, because we tend to simplify things for students even if this adds certain risks? I was curious because one local school was one of the last holdouts with round canopies for students in fore-and-aft style gear, until I think the year 2000. Their basic students used T-10's I guess, and advanced students used ParaCommanders but weren't taught to cutaway and had no pilot chutes in the reserve. So I wondered how that system would be regarded by others. There was one fatality to a student jumper at the DZ in 1993, who has about 21 jumps and was using a ParaCommander main, and had a main-reserve entanglement. I don't know whether one could blame the jumper's procedures or the equipment. For their time, the DZ trained a massive number of students, so even though the DZ was controversial, a fatality on the system isn't damning. (Edit: I don't know much about any possible student fatalities in prior decades.) When I had 200 jumps in 1995 I did go make a jump with them, the old Parachute School of Toronto before the original owner retired. It was my first round / belly mount /ParaCommander jump. Actually a King Cobra canopy, more or less a PC copy.

I find the choice of acceptable gear depends on the culture of the DZ and the camera flyers at any given time. At some places, you might be looked down on if you do tandem video without "the proper gear" -- some sort of fancy flat top helmet, ring sight, camera wing jacket. At other places, it is considered that one can get decent video without all that. I did video for years with a converted Protec helmet, no ringsight, and no camera jacket, and other than the Protec, it wasn't seen as an oddity locally. The video flyers I see without camera jackets do tend to be the light to medium folks. Without having the great range of a camera suit, one may need to adjust weights worn, or for a slightly heavier camera flyer, have a couple suits of different drag levels available. So the downside is that you don't just walk out all geared up; you do need to check who the tandem instructor is and what the student's weight is. I'm not such a lightweight as you. At 6'1" and 155 lb now, I often fly with a set of $10 used coveralls -- for a bit of drag range and much easier donning than a form fitting suit -- and just load up with typically 6 to 15lbs of weights. One local 120lb girl always uses her form fitting freefly suit, plus weights. So hopefully for you, local culture will allow you to fly without camera wings, and just a tight, slick suit and plenty of weight. Edit: I should note that Dragon2 has made the point that one can use wings as someone light... if one gets used to lots of weight... and probably a little practice to really 'hang on the wings' without having the body flat and draggy.

Well when you aren't jumping you can sit around and read dz.com, searching for the many threads by newbies about dealing with fear! (And a few threads about fitting in at the DZ). As for fear, one can work at figuring out if there's a particular thing that is at the heart of the issue. General fear on jump run but OK once outside? Or is it something specific, that one can deal with? For example: Need a good emergency procedures review? Or a little shaky dealing with the 3-D positioning of the circuit? If you can identify what is bothering you, then you can plan on what to study up on, what to ask instructors about, what to focus on during a jump, and what situations to avoid for the moment to keep things more manageable. Admittedly if you have 14 jumps then there's probably plenty to learn in just about every category. It can be a lot tougher to travel around to other DZ's when you aren't licensed yet, because a DZ wants to take a lot more care about finding out what you do and don't know. Other people will know better about how well some of the big winter-time DZ's handle students who come their way. Feel like an idiot? We were all dumbass students at one point. No matter how capable we were in the rest of our lives, we had a lot to learn about skydiving. And for what skydiving costs, a little fear and excitement gives you your money's worth. Conquering fears is all a part of skydiving.

There's gotta be someone out there in Texas with enough enthusiasm about skydiving or sense of history to want to preserve this material! (And with some space for boxes.) When I started in aviation, getting a huge pile of old Sport Aviation or Sport Aerobatics, years of magazines to read through, from someone leaving the sport or clearing out their basement, that was awesome. Maybe this stuff could be advertised on some DZ's facebook pages or something. (Although Mr Webb, while being generous, probably doesn't want to spend a ton of time trying to flog the stuff....)

I understand your feeling. Still, student instruction programs do tend to focus on keeping you alive for the next 1 hour, although with some view to teaching good habits for the long term. There are a million things still to learn about skydiving and gear at the awkward point which you are set free, off of instruction. While just about every skydiver is expected to have a knife, it has also been argued that it is exceedingly rare to actually need one outside of CRW. And I don't think I've ever seen a rental rig with a knife. So having a knife is somewhere vaguely between 'not essential' and 'really smart to have'.

Now I'm getting confused. Beatnik, aren't you and Rob saying essentially the same thing? Neither of you (nor I) have the exact dates pinned down off hand, but the trend was towards squares, almost everyone was using squares, so the CSPA changed their rules requiring squares for students. (And I guess it wasn't something dictated by the Tech & Safety Committee as so many rule changes are now, but came from a motion from the floor at the AGM. Hotly debated no doubt but it passed.) Thus the old Parachute School of Toronto had to leave the CSPA. They continued on with rounds for students for a few years until Lloyd retired. This is what I understand and matches what you guys said. Is that all not correct? Or are we getting into subtleties about intent? Lloyd did honestly believe rounds were better for students (so I've heard), but also wouldn't have wanted to replace all his gear all at once.

TomN.'s idea is an interesting scenario, and I guess one that has actually happened?! But in this case with the drogue apparently ripping off completely, one doesn't need stray lines during packing to be the explanation for a line dropping down and catching the handle. It can just be explained by the bag bouncing around in the burble on its own, with lines "everywhere". (The thing about the drogue disconnecting completely is something one might miss if one isn't reading the thread carefully. It was mentioned in a somewhat ambiguous manner in the original post. I nearly missed it myself. When he meant the drogue floated away.... aha, he meant it floated away unattached from the whole system off into the sky.... and not just 'floated' as in a slow bag extraction. I think!)

I'm no expert on PC landings so I'll cop out and see what the Gary Lewis ParaCommander Handbook has to say. It gives both the riser and the toggle option. OCR from the handbook: I didn't include the High Wind info, as that gets into more complex 90 degree hook turns!

I started at Grand Bend, ON, and they converted to squares somewhere around 1982. You'd know better, but I guess Bob at Grand Bend and Tom at Gananoque, ON were a couple of the pioneers of putting students on squares, probably having to get special permission from the CSPA to do something so radical? As for my current DZ they went to squares in 1987 when they moved to a new location, and went to ram air reserves somewhere around 2000 when they got some new used student gear. Squares for pilots? Ha ha as you say. They end up with everything from old military rigs to early 80s sport rigs with old rounds, plus a pillow in the main container.

Good for you but it slightly screws over others watching the thread -- the forum guidelines specifically recommend that people share publicly if they're going to share. That being said, there are minor things or things of interest to a particular DZ only that don't need to take up forum space. (Say, the DZ's colour scheme for marking which student rig has the 230's and which has the 260's and 290's.). As for footwear, maybe pick something "in between" what you talked about. Solid boots do provide some ankle protection. After all you aren't wearing skis, and the leg is really flexible at the ankle, so a higher shoe can reduce the chance for tipping it over at that point. And that's what breaks the lateral malleolus, which is I think what you broke at the bottom of the fibula. But solid boots can have treads that grab the turf too easily, making even the slightest slide difficult. And AFF instructors may not want them on a student as a boot to the face is worse than a running shoe to the face. Skate shoes are used by quite a few jumpers, particularly with faster canopies, because of their smooth sole. But I do find they have little cushioning vertically compared to a regular running who, which one might prefer if one isn't always sliding in or running it out perfectly. Sliding can either be used for the whole of a fast landing where a jumper is sure they won't drop down on their spine with excess vertical speed, or as just the start of a landing where they transition to running out the landing. But that's not really for a student; that's for down the road. A student will want to keep feet together for mutual ankle support and be ready to PLF, like everyone says. Sure, after some jumps a student might see they are having a good landing, with near zero vertical speed, and 'step down' with one foot and take a couple steps with little wind. While that is realistic, an instructor can't recommend that, because otherwise some student will stick a foot out when their flare isn't perfect and they haven't gauged vertical and horizontal speed right... and break their ankle. Gotta run. I'm off to test jump some new student gear at Skydive Toronto; probably the last chance this year.

There's no major geometry issue, is there? Haven't thought about it in detail. Certainly there is the misrigging possibility, although it isn't like tandem drogues being hooked up every jump. A sewn double ended loop would be stiffer though. Thanks for adding to the thread Mr B., and for the pointers everyone else.

If it is making fun of people asking something like "my brother is a pilot, can I jump out of his plane?", well, why the heck not? [Ref.: A current thread in the Skydiving forums.] If my brother drives a car, can he give me a ride in it and drop me off downtown? Yeah sure, you expect the answer to be yes. There are a few caveats, sure. Maybe my brother can't do it in his employer's car, or earn money off it on, or can't do it on a learner's permit, or something like that. So it seems entirely reasonable for someone to ask a question like that about jumping out of airplanes. I guess if your brother is a chef of course you can cook in his kitchen with his permission. "His" kitchen as in his own. There's no license to pick up a kitchen knife or turn on a stove. If he's employed in someone else's kitchen, I don't know, maybe with their permission. Can he cook commercially for the public? I don't know the rules on that. Those are different situations.

I can't recall, is there a name for a student system where there are cutaway cables on the cutaway handle as normal, and cutaway cables on the reserve handle too? Where the risers have a double ended loop, each end being pinned in place by a cutaway cable. The idea is to retain the advantages of the SOS in that any handle pull by a dumb student is a correct handle pull for dealing with a mal, while still allowing using the TAS training to pull both handles, reducing later transition training. (Of course a handle pull at too low an altitude is wrong on any system.) Who does or has made such systems? I know Flying High in Canada has done rigs like that on request, but does anyone know some history? Such rigs are fairly rare.

Hang on, aren't we talking about the bag to bridle connection on the Sigma, which is invisible when the rig is already packed? Not much the TI can do about that.

You're right, that would be weird. I think we're getting confused over axes. It's not rolling around the long axis. I'll start again with an example of my own to see if we can get the same mental model, which should make it all clearer: Ok, so there's an ice surface, and a center point where a rope is being swung in circles. The weight at the end of the rope is a metal bar sliding on the ice. Swing the metal bar around in circles, 180 deg/sec. If you could get a drone to hover over the bar as it goes in circles (with impressive piloting skills), without turning the drone's direction, a camera on it looking down would see it rotating 180 deg/sec. That's showing the rotational momentum it has. If the knot at the metal bar fails and the bar goes flying, off it goes in the direction it was going at the moment it was let go. But it still has that rotational momentum, so as it flies off, it is also spinning about the vertical axis. (Axis up and down relative to the ground). And that's the skydiver who chopped from his spinning mal, spinning away.... [inline spinning_bar.jpg] As something of a live demonstration, I have a video on youtube,showing me intentionally cutting away one side of a square 190 F-111 canopy. (Poor video quality though.) Even that big old canopy gave me 360 deg/sec rotation. Quite a ride, and I certainly had plenty of that rotation still, when I pulled the other cutaway cable. I probably spun a couple times around (around the vertical axis relative to the earth), somewhere aong the way also flipping myself belly to earth before deploying an F-111 main. Guess I slowed the turn enough, as I didn't get line twists on deployment. Video with a measly 51 views so far: "One-sided intentional cutaway" https://www.youtube.com/watch?v=75t0pMauATo

I was trying to avoid any dz post today but can't help it. I've been fighting that line of thinking for years in threads on mals. In itself, it is true. But there's more. It is true that of you are going in a circle (approximating a downwards spiral) at 180 degrees a second, yes you fly off in a straight line. However, people forget that superimposed on that is a body rotation of 180 degrees a second that is also happening. You fling off on a straight line, tangential to the circle... but still spinning around your center of mass...(at the same speed you were spinning around your center of mass before you chopped.) This may be soon be slowed by drag, or conscious or subconscious action on the part of the jumper, but does exist. That doesn't change the idea that MARD deployments should have fewer twists in general, due to the speed of deployment. I just try to fight those who over-sell whatever skydiving technology they favour. Get an RSL or get a MARD, they say, BECAUSE "RSL's don't cause line twists because you are flung out straight from a spiral!" or "MARDs work so fast you never get line twists!" B.S.! RSL deployments can cause twists. MARD deployments can cause twists, but likely at a much reduced rate. I'm not attacking the technology. The vast majority of the time, reserve line twists are not an issue. Only very occasionally they can be serious enough to cause problems especially if low. (It has killed or injured people so shouldn't be forgotten. But reserve line twists are not considered much of a hazard overall.) Normally though, if a MARD (or even RSL) gives you twists... well at least you've got a few hundred or quite a few hundred extra feet of altitude to deal with it! A net benefit. (I say this as a jumper who pulls cutaway and deploys reserve on their own, and don't mind trying to get a bit stable in between, altitude permitting, but am happy to jump MARD rigs too.) Gowler gets at the issue that twists happen for different reasons. It could be that the jumper is spinning at the point of cutaway (and the jumper and deploying canopy don't spin the same amount by the time the canopy inflates), it could be that the bag gets dragged out unevenly from the container and gets kicked into rotation, and of course once you have 1/2 a twist and some momentum, such as from loading a riser unevenly on opening due to body position... then you can keep spinning up. I'll use Gilead's video from post #2 as an example. I'm not going frame by frame so this is really just approximate. He's spinning on his back. From the flash of cables to being upright, he continued to spin very roughly 1 turn. When he first sees the reserve, it has I think one full twist in it. Who knows exactly how much the bag rotated along with him as it came out, but somewhere about a full turn of difference happened. Who knows, maybe the was out of the bag so fast that the bag only rotated a quarter turn and then the deploying canopy would be draggy enough that it would stop rotating quickly. But he still has momentum, so keeps spinning up. Something like 4 full twists that he has to wiggle his way out of. So even given that the MARD was dragging the reserve out while he was spinning on his back, it doesn't look like the MARD really gave him twists. It was largely just a function of having some rotational energy left when he was past that critical 1/2 twist rotation. It's a good example of how a "MARD gave him twists" (considering the whole reserve deployment procedure) while at the same time the "MARD didn't give him twists" (the Skyhook must have extracted the bag pretty cleanly). So a MARD may be more likely to avoid giving a jumper twists (how often?), but it is useful to have a thread where it is pointed out that MARD's don't magically cause them to never happen.

And you are using your prerogative to determine incompatibility between certain components, at least as far as what you'd choose to pack. Since I haven't tried to pack that odd Strong + National combination with rather different bulk distributions I can't say how practical it is to make it work well.... (Interesting about the Preserves in National packs -- I now see the latest manual lists all 3 Aerostar sizes plus the Preserve I, depending on model. The web site still just shows what must be the 3 Aerostar sizes.)

Ok of course no problem. I hadn't been clear on what you were objecting to. I was just using 750 and 1000 as simple approximations, rather than arguing numbers in between. Clearly the pressure behind on object in freefall will be lower. And higher on front, eg highest at the stagnation point. For an AAD inside a skydiver's rig, with the skydiver on his back, I'm not sure just what the pressure will be -- due to the large size and volume of the pack, the pressure increase at the sensor might be a fair bit less than at the stagnation point itself. In any case we don't know exactly what sort of pressure changes exist at the AAD sensor in different body positions.

That's an interesting line of inquiry you've dug up. The way I've always heard it was that patents somehow locked up the single cutter for Cypres, which is why others are stuck with circular cutters. Anyone hear different? Seemed odd to me that a straight line (like the cutting edge of a flint tool as used by proto-humans on the plains of Africa) could be patented for cutting something, but patents have their own complexities and exist in their own world...

He said the pressure is 300 ft "higher" in quotes, implying higher in altitude, not numerical magnitude. "Confusing?"

Do you trust your reserve to open? Heck, someone is always wanting to inspect it every 180 days (or maybe some other number where you live). Must be something dangerous with it?? You may argue engineering quality if you want, but I think the 4 year Cypres cutter requirement is clearly based on their inspection philosophy rather than engineering issues. Cypres cutters have clearly been the most trouble free. (Although one can, say, crack the hard plastic where the wires lead in to Cypres 2 cutters) Also, the design philosophy of their one blade cutter seems superior when explained, compared to the two blade (circular blade) that others have had to go with due to the patents Airtec uses.