pchapman

As a general comment (even if the original poster knows this well):

As far as I know 8015 is the property of the SAE and is available from them only by purchasing it. But I sure like to be able to know the standards by which my equipment may be certified.

Also useful for those interested in certification, is to check out PIA's proposed TS-135 available from their web site.

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In order for there to be bag strip, you would need one of two scenarios to happen: line dump, with the unstowed line having enough mass to pull one of the locking stows free, or the safety stow must break.
[...]
SO unless one of the bites gets pulled out, or the safety stow breaks, you're not going to strip the bag off the canopy.

There might be one more failure mode too, where the canopy starts to dump out one of the lower corners of the freebag, before the safety stow releases or all lines are paid out.

This would result from freebag that is fairly open in the corners, and an old or weak safety stow stretching a lot, and maybe some sort of asymmetry in the deployment process.

I believe this is something Jump Shack recently claimed in one of the threads about damaged reserves, but I don't recall exactly where. The point was that the safety stow didn't have to break for the canopy to get dumped.

I don't know how likely this really is, but the idea should be part of the whole argument.

Since reserve snags are a popular item in this thread at the moment, I'll add a minor story:

A girl at the DZ, with maybe a hundred jumps or so, was jumping her first rig, a well used one with a round reserve.

It wasn't quite the old days, more like 1991, so there still were plenty of used rigs with round reserves around.

The actual reserve system, however, was from the old days -- a diaper-less round with the lines stowed in the pack tray.

One day she mal'd, chopped, and went to the reserve. BAM!, a hard opening and a big holes in the canopy that weren't vents. One line broke and two panels were torn between reinforcing bands. She wasn't a big person and took the hard landing without real injury.

What had happened? In the pack tray was one grommet with a flange bent up 90 degrees. Those old rigs weren't heavily reinforced around the 2-pin reserve closing loop, so the flexing tray allowed the edge of a grommet to stick up a bit, in the path of all those lines stowed in the pack tray on a no-diaper reserve. One line had snagged the grommet, resulting in the out of sequence deployment and luckily 'only' a broken line and a couple panels.

Another time the same girl blew open the center top skin of her main from nose to tail. I was looking down at her after her opening and wondered for a moment what the wavy fabric was, but just went back to flying my own canopy. The canopy stayed inflated. (This was an F-111 7-cell, with maybe 150 lbs total on a 220 or so canopy.) After landing, she complained about the hard landing and crummy flare, and went to pack. She's yanking on the packing tabs one by one while flat packing, 1...2...3...and then #4 pulls way out from the rest of the canopy, attached to torn fabric. Only then did she realize she had had a mal.

So in her few years in the sport before retiring to start a family, Sylvie had managed to blow up both a main and a reserve canopy.

(While I do like the real old days stuff from the 60's and 70's in this thread, I hope there's some tolerance for newer stuff here, without getting finicky with dates! There is a "Scary Stories from Today" thread, but I haven't seen anything in between.)

The only recent North American use I've seen of the "POD" term was for a special deployment bag for a BASE system. I presume it was called a POD rather than deployment bag mainly because it was longer, about one third the length of a canopy being packed. It also happened to have a #8 grommet on top to allow the bag to slide up to the pilot chute, and used a reserve d-bag style pouch for stowing the lines.

I believe the company is currently just calling it a sleeve instead.

This is just a minor example of how an old term was reused for a type of deployment bag that in some ways resembled the original POD.

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Chest straps are not designed to be loaded by being pulled outwards or downwards

However, it may help jumpers that the main lift webs and chest strap aren't rigid beams, but are flexible and can in some cases move in order to better accommodate unusual loads.

E.g., yanking the chest strap outwards in a 'V' shape doesn't just try to peel the strap away from the MLWs. The MLWs will twist, so that the forces along the chest strap feed (as perhaps intended) nearly straight along the plane of the MLWs. And if one has chest rings there's even more flexibility to allow good load paths.

(Actually, isn't the load of someone pulling outward a little like the force of a jumper's torso pushing out on the chest strap while being pulled upright on opening, if the MLWs over the shoulder aren't taking all the load? So the pulling isn't entirely unlike something the rig might be designed for. Pulling downward along the direction of the MLW, however, is something I don't expect the chest strap to be designed for.)

I wonder what rig designers actually have chest strap load information, rather than just designing by precedent, using designs at least as strong as what everyone else has done in the past! The issue of what types of loads chest straps are actually designed to handle, is unclear to me.

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So what IS the general rule of thumb for choosing a reserve size in comparasion to the size of the Main Parachute that you'll be using?

Some thoughts that focus more on the real world than the ideal world:

-- You'll get an idea of common size ranges (relative to the main canopies) in the Classifieds anyway, if you are looking at buying used.

-- Let's face it, very often the reserve size people buy is "the smallest they dare".

Someone might figure that they can handle a PD143 without any real problem, and then buy a 126 (the next size down) because they really want something small on their back, and that way they should be able to handle it well enough. After all, for main canopies, if you're really comfortable with a given size, then trying out one size smaller, if one is being careful, is normally considered OK. (Although for reserves there's the added complication that they don't fly like most mains.)

On the other hand, the person who thinks they'll be comfortable on a 143 may decide they'll go one step the other way, up to a 160, for that extra margin in case of a bad landing area, unconscious AAD save, injury, etc., and that the bit of additional bulk shouldn't be a problem.

It all depends on one's personal philosophy.

-- From the idea mentioned above, of hoping to 'be able to handle one size smaller', one can make this rule of thumb:

The reserve should be no more than one size smaller than the main, for novice to intermediate jumpers.

I think that may be reasonably true, but open to attack because it is so short!

-- Time is a factor. A novice may plan to keep a rig for a few years, and after the first season or two downsize the main. They don't want too big and bulky a rig. So they buy a rig with a relatively small reserve that they think they'll feel comfortable with next season... despite being a little uncomfortable with it this season. It's a calculated risk that some accept.

Reserve sizing ends up being part of the whole issue of long range planning of downsizing progression and how long to keep a particular rig or main canopy.

-- Despite all the differences in personal preferences, what is a decent wing loading?
A couple experienced people mentioned a 1:1 wing loading. That sounds quite reasonable and fits well with what manufacturers say.

PD's recommended maximums:
Most of the time it is
0.85 for Novice
1.0 for Intermediate
1.15 for Advanced
1.4 for Expert
[Based on their weight vs. canopy chart. These numbers hold for most sizes but don't apply in some cases for very large or small canopies.]

Aerodyne for their Smart recommends:
1.0 for Novice & Intermediate
1.4 for Advanced (but that seems to correspond to PD's Expert category, as Aerodyne doesn't have an Expert category.)

Precision's R-Max: Couldn't find any info on their web site.

There are no specific definitions of categories like Novice or Intermediate, however.

(I won't get into issues concerning high wing loadings with older designs of reserves, or the desirability of lighter wing loadings for very light jumpers.)

-- One answer in this thread suggested that mains should be sized to be compatible with the reserve in case of a two-out. For safety's sake, that seems true on its own. But in practice I don't see people paying attention to that factor. Or at least, other factors dominate the decision.

(It can be argued that for very small main canopies, a bigger reserve is better, for the much more likely case of a plain reserve ride, compared to the rare but dangerous 2-out situation.)

A lot more could be written on the reserve size subject to provide a real guide to novice jumpers.

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The way I understand it in Canada our rigger ratings are administered by CSPA and so there is no government body regulating riggers here.

I can't find anything to dispute that. The only thing I've ever found in the Canadian Air Regs is for demo jumps over built up areas etc. Then the reserve has to have been packed by a "certificated parachute rigger". Other than for that, a bogus reserve pack job etc. is just an internal CSPA matter.

(I hope everyone still feels free to discuss the 'bogus pack job' issue as it would apply in their own country, whether that's the USA, Canada, or anywhere.)

There have been good posts about the "dealing with danger" aspect -- such as what all is covered in skydiving training, and how one is trying to act in an informed, responsible and safe manner.

Another aspect is to address the "why would one want to jump out of airplanes?" issue. It can be a photogenic sport so for me it helped to show videos to friends & relatives. One could pick something well shot and edited, showing beautiful skies, people having fun in the air, nothing too extreme or filled with skydivers acting like maniacs. After seeing videos, I've had little old ladies say they now understand why I skydive.

Two weeks ago Friday I packed some tandem reserves for the DZ. Saturday morning an instructor does his tandem recurrency jump, first of the season, with an licensed jumper on front who had never done a tandem.

The instructor has a problem with stuck toggles and goes to the reserve. Good practice indeed for the instructor & excitement for the passenger!

Sunday evening after Easter dinner with relatives I swing by the DZ & pack the reserve up again...

I don't repack the main canopy.

Why? It seems to be one reasonable way to do things, it is the way I learned it, and is the way it 'usually seems to be done around here'.

The main risers are disconnected to make the reserve packing easier, to flex the risers briefly at the rings, and to clean the cables. After the reserve is done, the risers that were carefully laid aside are reconnected and the customer told to do a repack since it is considered his responsibility to confirm that the reconnection is correct. Often I close the main container with one or two flaps as a temporary measure to make the rig easy for the customer to carry off, yet still remind the customer that a repack is needed.

(Some jumpers may choose to un-bag the pack job, do a line check while the canopy is still rolled, and re-bag the canopy, 'saving' part of the pack job. But that's an advanced technique done at the jumper's discretion.)

I was in contact with the rigger. He said it was the first time he assembled those type links and had a tough time getting clear info on how to do it. Only later did he see a clear picture and by then had forgotten how he'd done it.

Since the Aerodyne manuals have shown a clear drawing for at least the last 2 years, he probably wasn't working off a manual. He may have had vague or misinterpreted verbal instructions.

I seem to recall that Aerodyne ships gear with almost no paperwork, just a CD of manuals. This can make it a little awkward to quickly get gear assembled for someone unfamiliar with it.

The lesson is a simple one about reading the effing manual if one isn't absolutely sure about something potentially critical.

Attached is a photo of how the link was found, once rotated out of the riser. It's still a bit hard to see what's happening... but of course that's the issue when inspecting.

The other attachment is the drawing from the manual for that Aerodyne soft link design.

I came across reserve soft links that weren't assembled according to the instructions. They were of the 'ring' type, like Aerodyne, Precision, and PdF use. (Not the PD tabbed Slink type.)

The links had the end of the line simply lark's headed around the ring. The line did not first pass through the loop at the other end of the line and then pass over the ring. It looks 'fairly' safe and secure but the load path isn't as the manufacturer intended, and the line larks headed on the smooth ring does not tend to stay cinched as tight as normal.

I just want to double check that there aren't any alternative soft link assembly methods I haven't read about. Sometimes in rigging there are 'accepted' or 'approved' techniques not mentioned in the manual -- but I haven't seen that this is the case here!

I changed the links back to the factory method, and it will be discussed with the rigger, who is experienced and current. Other details will not be divulged.

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"The Swoop Streamer - Learning canopy manuvers with a visual reference at safe altitudes."

Gary & Brian will obviously realize that there could be problems in getting more than just a small amount of skills transfer from the 'training', to real swoops over ground.

A streamer just doesn't have the same visual picture & cues as the ground has. The streamer might help more when one is working to learn swooping a particular object (like an entry gate). On the other hand, the streamer drifts with the wind, so it isn't useful in training to plan one's approach for different wind conditions.

It concerns me that the descent rate of the streamer would tend to train a jumper to "aim low". A jumper just aiming straight for the top of the streamer may pass above it because it is moving down away from the aim point. Lead vs. lag pursuit curves come to mind. Not leading the streamer enough may also result in intercepts that succeed (and are successful in the jumper's mind), but only because the jumper maintained a high rate of descent without a full flare.

Aiming low and maintaining a high descent rate are not good behaviours to transfer to the real ground swoop.

All this reminds me of the experience some people will have in catching freebags under canopy. I've only done the airplane & toilet roll thing.

In any case it sounds like fun and may provide some extra canopy skills. I look forward to reports too.

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The section right above your quote says: "TSA Security Screeners must visibly ensure that the cylinder is completely empty and that there are no prohibited items inside."

I got the impression that the life jacket exception is an exemption from the requirements of the whole paragraph. Otherwise it's not much of an exception. There would be little point in being allowed to take along emptied non-refillable cartridges (if they are indeed non-refillable).

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I guess it is all about who you talk to and when you talk to them.

Agreed! Check ahead.

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Are you aware that you can't carry C02 cartridges on commercial flights? Checked or carry on.
http://www.tsa.gov/public/display?theme=177

There appears to be an exemption for life jacket cartridges:

"NOTE: There is a compressed gas cylinder exception for both carry-on and checked baggage that allows 2 compressed gas cylinders fitted into a self-inflating life-jacket and 2 spare cartridges with the approval of the aircraft operator."

It's on the TSA page
http://www.tsa.gov/public/interapp/editorial/editorial_1188.xml

but unfortunately NOT in the pdf list found on the page previously posted.

A similar exemption exists here in Canada.

1 reserve ride in ~1500 jumps at #608

It was a CRW wrap so when the whuffos and students ask about canopies failing, the simple answer is still that I've never had a canopy malfunction on opening.

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Fuck you Newton, and curse your silly "rules"!!!

No personal attacks allowed in the forums. (On dead people too?)

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There seems to be a 'potential barrier' between the regular flat track and VKB track: if you assume the characteristic VKB body position from the beginning, you will not achieve enough speed for it to work. You have to go superterminal first by diving head down, then when you're past the 'barrier', transition into track.

In this discussion, does 'body position' refer only to the body shape, rather than both body shape, and body angle relative to the horizon?

Our jumping terminology may not be consistent on such things. If body angle were being included, then of course it is normal to start more head down and then angle less head down. If body angle were not, then the issue is more interesting.

(If I'm not being clear, an example is that if someone found that 20 degrees angle of attack were ideal at every speed, and a 1:1 glide ratio were the best achievable, then the jumper would start 70 degrees head down and eventually transition to 25 degrees head down as forward speed picked up.)

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The lines with slider stops have the stop at the bottom of the stablizer just like every other canopy.

Thanks, I failed to really consider how most of the end cell line attachments are covered by the stabilizers, on most canopies with flares.

Only SOME end cell flares aren't covered and protected.

E.g, No stabilizers at all in photo 1 of a current Flight Concepts reserve. And no stabilizer protection for the A-line flares of a Glide Path canopy in photo 2. The colors make it apparent how the end cell flares are still there but covered by the stabs for the B,C, & D lines.

To add a little bit to all the time & altitude stuff, particularly what 980 and billvon wrote about, I timed some of the openings in two RWS Skyhook videos, just using a stopwatch, not frame by frame analysis.

Time from cutaway to fully inflated canopy:
3 sec typically, from a straight flying canopy

As we know, that's not the same as having a canopy flying stable. In one case on video, the canopy had a big swing on opening so it was 2 more seconds until the canopy was flying close to normally. (The RWS video with the slider down "100 ft" cutaways shows another example of the big difference between just 'open' and 'close to flying properly'.)

From a spinning canopy, time to full inflation:
2 sec typically in the best cases
2.5 & 3 sec seen in cases where the reserve snivelled for a moment

Time to extract the canopy from the freebag:
1 sec on the videos from flying straight
1/2 sec by billbooth's frame analysis, cutting away from a spinning canopy

To go from cutaway to canopy extraction one needs maybe 8.5 ft for lines (PD-126 A-lines), at least a foot for the risers, a foot for the bag, maybe a couple feet for the stretched out canopy if you want to include that, and 7 ft for the bridle (Billbooth once posted 7 ft to bag to skyhook, plus 5 more to PC). Total 17.5 to 19.5 ft.

In 1 second (ignoring minimal air resistance) one accelerates downwards 16 feet. If one starts with initial downwards speed, one has to add that on, e.g., 31 ft total vertical distance if starting at 15 fps down. (I'll leave aside just what the main canopy is doing, as one needs enough vector distance [Vector distance?
In videos a cutaway may start at the camera flyer's level, and end up with an open reserve not far below, but of course that's relative to the camera flyer who is also descending.


So for a slow speed cutaway, the Skyhook does about as well as could be expected from the simple physics. There's significant vertical distance just to get the canopy extracted, maybe 17, 20, even 30 feet, which is going to take a full second or more. But the reach, peel & pull beforehand, and the canopy inflation afterwards, are going to take more time and distance than the part that's under billbooth's control!

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I'm wondering which manufacturers / containers still use MA1's?

I repacked a modern GQ pilot's rig last year. It wasn't just a plain old round but one with a lot of interesting features clearly derived from their military experience, and a rating of 280 lbs at 200 Knots. Despite all that, it used a lowly MA-1.

It seems that MA-1s have a lousy launch, lousy snag resistance, but if an MA-1 finally does find some clean air to catch, I guess it'll catch it very efficiently in any attitude.

That's a bit of thread drift, but it is interesting to what degree reserve PC weight, and how it is balanced, affects the time for parachute deployment. A low altitude BASE jumper wouldn't be thrilled to tie a one pound lead weight to their PC's cap! Yet skydivers don't start right at zero airspeed, and plenty of different designs get TSO'd. (TSO requirements as I recall are sloppy in that there's no maximum speed specified for the low speed case?)

In general, canopies using flares are less common than those with direct line attachment. But both are considered acceptable in skydiving. I'd like to dig a little further into the issue to learn more, because there are some features that seem like they might make canopies with flares slightly less reliable.

I've long wondered about canopies with flares, well before the hot issue at the moment about a structural failure on a reserve, apparently of a design using flares. (http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=2177335;)

Some possible issues:

-- SLIDER STOPS ON FLARES MAY BE MORE LIKELY TO ENTANGLE WITH LINES:
As I wrote in that other thread, is a slider stop which is a lump at the pointed end of a flare more likely to entangle with lines, than a stop that is embedded within a stabilizer on a direct line attachment canopy?

On the latter, the stabilizer and associated fabric tapes are still flexible so it isn't impossible for a line to wrap, but it seems to be a better design in that particular regard.

-- FLARES SEEM TO BE LIKE PACKING WITH THE SLIDER PARTIALLY DOWN: Flares (and their slider stops at the end cells) keep the slider quite a few inches away from the canopy in the pack job. This would seem to make it harder for the slider to control the initial stages of opening, and harder to tune the design for good, consistent opening characteristics, although obviously plenty of canopies do work OK with flares. It might be OK for big F-111 but get tougher for small zero-P canopies. (I just looked at a fuzzy photo of the Flight Concepts high performance canopy, the Rage. I can't tell whether it has flares, but if so, they must be tiny ones!)

It certainly isn't the same as a sloppy pack job with a slider a few inches off the stops, for the design with flares still keeps the slider in a consistent position on the four line groups, promoting a symmetrical opening.

-- FLARES COMPLICATE RESERVE PACK JOBS slightly, at least in relative terms for those who are more used to direct line attachment canopies. The flares effectively extend the length of the canopy, sometimes making it harder to get the S-folds to neatly shorten the canopy to go into the freebag. Also, after the S folds, the grommets don't end up near the base of the pack job, but are pushed up into the pack job by whatever length there is in the flares. (Glide Path and Flight Concepts manuals that I recall seeing, show pulling the canopy tail down to the bottom of the flares when cocooning the pack job, before S-folding it.) Both because the grommets are buried in the pack job, and because they may be at the fold point of the first S-fold, it becomes harder to control the slider's position. (Of course, riggers have to control the pack job, whether or not they consider a particular pack job easy.)

-- FLARES COMPLICATE MAIN PRO-PACK PACK JOBS: This is a minor point. The added length of the flare just makes it harder, for a given size canopy, to reach down inside the canopy and flake it.

-- FLARES MAY INTERFERE WITH SLIDER MOVEMENT: I've seen some main canopies where the slider stops are arranged so that when the slider is tight up against the canopy, parts of some of the flares do or can go through the slider grommets. To what degree does this increased bulk going through the grommets increase the chance a mal with the slider stuck up on the flare with some sort of tension knot?

I recall a Manta canopy mal with the slider hung up, that was blamed on a packer who admitted being frustrated and jamming the slider up against the canopy very hard, apparently getting some of the flares into the grommets.

While it may be comforting to have as little bulk as possible going through slider grommets, Paraflite did have reserves (with direct line attachment) that used slider grommets much smaller than the regular #8. So big grommets aren't considered the only way to do things.

I don't have any big bias against flares, but am more comfortable with direct line attachment canopies. I realize that canopies with flares do seem to allow a more gradual transfer of loads from lines to canopy, with less point loading to deal with. Despite any structural advantages there, using large flares does still result in significant increased bulk.

Maybe jumpers with more 1980's experience, when canopies with flares were more common on main canopies, might be able to comment on whether flares were seen as a complicating factor or not.

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He is the funnest subject in french skydiving. A bit like Lutz in the US.

Over in Europe you know more about him and must have some reason to make fun of him.

But when all the recent high altitude attempts got going, there were about 4 or 5 people going for it. I don't really know the situation, but the only ones I hear really doing anything are Fournier and Stearns. And even Stearns gave up the attempt for a while.

Fournier actually travelled to his launch site a number of times in preparation to go. He had various problems like a torn balloon, or a vital ground crew member with a heart attack. Unless it was a big scam, it seemed as if Fournier was truly trying to get ready to launch, and not just taking a holiday in Saskatchewan, Canada for some reason.

So maybe he's an odd fellow, or isn't current in regular skydiving, but on the surface he has significant credibility in the high altitude race relative to his competitors.

I really don't know the details so I am curious why he's such a joke!

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Out of curiosity:
Do pilot rigs contain ram airs or rounds?

(etc)

Pilot rigs have just one chute. The plane is their "main", the rig on their back is the "reserve".
99%+ of the time it is a round canopy. There's no required training. There are usually a couple pages in the manual about how to use the chute - how to deploy, how to steer, how to land. For most pilots, it's a matter of getting out of the airplane, getting clear, pulling the ripcord, and worrying about everything else when that time comes! For any knowledge beyond that, it is up to the pilot to educate himself. Some pilots will ask a few more questions when buying the chute or when talking to their rigger.

PS - One save I know of is by a rigger named Julian who started jumping in the Toronto area but later was at Chicagoland or thereabouts. He got one or two saves a few years ago from the pilots of a Christen Eagle aerobatic aircraft who had to bail for some reason.