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Chris3D

Canopy performance vs. malfunction rate/severity

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So I've read in several places that lower performance canopies (lower wing loadings) are less likely to experience malfunctions, and when they do occur, they're less violent. Can anyone elaborate on if, and if so, why this is true?

I could see, for example, how a faster flying canopy (resulting from a higher wing loading) would be more prone to winding up the lines in a line twist, spinning the jumper out horizontally. Yea, I've probably been watching too many YouTube videos :P, but that seems like it'd be pretty damn scary.

What I'm having a harder time understanding is why a higher performance or higher loaded canopy would be more prone to malfunctions in the first place. Is it a case where the initial malfunction causing conditions are the same, and a lower performance canopy will simply tolerate them better and/or resolve them naturally (a few line twists, to continue the example), where a high performance canopy will wind them up causing a more serious malfunction?

In other words, is it not as much that they malfunction more, but given the initial conditions of a malfunction, a higher performance canopy is more likely to amplify those conditions into a full blown cut-away requiring malfunction?

Sorry if this is a common knowledge question, I'm just trying to wrap my head around the physics of precisely how different gear choices will effect the likelihood or severity of malfunctions.

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Higher performance canopies are not more likely to malfunction (for the most part), but they are more likely to turn a 'problem' into a 'malfunction', with the difference being that a 'problem' can be fixed and a 'malfunciton' will require a cutaway.

Line twists are a good example, where you could just kick out line twists on a slower canopy, but a faster one might resist or start to spin making it tough.

There is some thought about the aspect ratio making a line over more or less likely. A lower aspect ratio being a more 'square' canopy might have less of a tendency to line over due to the shape and the difficulty of a line getting all the over the nose. A higher aspect ratio, or more rectangular canopy, with a thinner chord (the measurement from the nose to the tail) might make it easier for a line to get over the nose.

It's all moot, however, because good packing, maintenance, and use will prevent most malfunctions.

For a new jumper, simply stick with canopies and WL appropriate for your experience, and you'll be fine. By the time you jump something with an ability to 'spin up' on opening, you should have the experience to handle the canopy and not allow it to spin up. Proper body position, and how you load the harness during the opening can effect this, and that's why you wait until you have the 'feel' of openings to jump those types of canopies.

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...In other words, is it not as much that they malfunction more, but given the initial conditions of a malfunction, a higher performance canopy is more likely to amplify those conditions into a full blown cut-away requiring malfunction?

Sorry if this is a common knowledge question, I'm just trying to wrap my head around the physics of precisely how different gear choices will effect the likelihood or severity of malfunctions.



That is exactly it. For example, line twists on student canopies are commonplace. I had them on every static line jump. They don't cause much more than a slow turn. On my 190 Triathlon, they happened rarely, but when they did, they usually caused a turn, but not a terribly rapid one. On my (current canopy) Sabre2 170 the few times they have happened, the turn is faster, but not violently so. A friend has a Diablo 170 at about 1.4:1 and he has had a cutaway due to line twists (and another he took way too low fighting out of them). Another friend has a Jedei 136 at about 1.7:1 and if he gets any twists during opening, he has to get out of them before the canopy fully inflates or he has to chop it.

Brake fires are similar. Student canopies, no big deal, just a medium slow turn. My Tri, moderate rear riser input would stop the (fairly rapid) turns, My Sabre2, I just had the first one and I couldn't stop it with the rears and had to pop the brakes, and it was a pretty wild ride. My friend with the Diablo had a cutaway due to spinning line twists that turned out to be a brake fire (we found it when we untwisted the canopy).

It's one of the reasons smaller, faster canopies require experience to fly safely. "Being careful" and "Mad Skilz" may let a jumper handle one when stuff goes right, but when the defecation hits the rotary oscillator, being careful won't be enough.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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how about you do a jump to start with!?



Perhapse I did the wrong type of jump, because the answers to my question never magically appeared in my head! :P

And thanks Dave and Joe, that confirms what I had thought. The reason I ask is that my wife has expressed interest in learning to skydive. On the one hand, I would love for her and I to be able to enjoy the sport together, but on the other, it scares the hell out of me because she tends to freeze up in stressful situations. The more we can eliminate the likelihood and/or severity of all-out malfunctions through gear choices, the more I'd/we'd be comfortable making the decision to start jumping.

I've watched videos where a canopy will spin a dozen or more twists in the lines within the space of about 3 seconds, flinging the jumper out to the side under high G's, and I honestly don't know if she'd be able to function in that type of situation. If that's far less likely to happen on low-performance canopies, it would reduce (some of) my concern.

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If that's far less likely to happen on low-performance canopies, it would reduce (some of) my concern.



"Low performance" in this case means both a lower wing-loading, and a lower aspect ratio. Read up on "aspect ratio". Wide skinny tapered wings are more likely to go crazy than more blocky rectangular wings.

And don't think that "low performance" canopies are any kind of guarantee against scary malfunctions. They aren't. Malfunctions can happen to any canopy at any time. And if you jump long enough, it WILL happen sooner or later. So you should have the mental mindset to be able to handle that. If you don't, you shouldn't get involved in this sport.

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So, you've asked this question in two different ways (so far) on two different posts. It's not that it's a bad question, per se, it's just that to some extent, you're putting the cart before the horse. From what I can tell, you've made a single tandem jump and are considering getting into the sport. You're doing your homework, which is good - to a point. But it also seems that you're starting to believe that you have the knowledge & judgement to make recommendations to your wife based on what you've learned through this research. No offense intended, but you really don't.

What I'd recommend instead is to take advantage of the whole cadre of professional instructors at your local DZ who have years of experience and training under their belts, who will be more than happy to help assess your (and your wife's) readiness for solo skydiving, based on an ongoing assessment of your understanding of the ground training, and your performance in the air. Instructional programs are carefully designed to introduce information on a gradual basis to prevent information overload, and to allow for continued expansion of the knowledge base and the situations that a skydiver is trained to deal with. As much as possible, the first few jumps will be more "controlled" (as much as any solo skydive can be "controlled") and as a student demonstrates understanding and proficiency, he will be allowed to progress and will take on an increasing number of responsibilities for himself.

(This is not to say that a student making his first solo skydive isn't taking on an immense amount of personal responsibility immediately. He is).

What I'm saying is this - stop watching videos, stop trying to learn to skydive on the internet. Stop trying to decide if your wife is ready to jump or capable of jumping. If you're ready to get started, get started. If she's ready to get started, sign up together. If either or both of you is not "getting it" your instructor(s) should put on the brakes and keep working with you until you get it. If you're not performing well in the earlier jumps with a more controlled environment, they'll keep working with you in that more controlled environment till they believe you've demonstrated the aptitude to move forward.

And, those same instructors will continue to teach and advise you as you progress through your student jumps, and as you start to make decisions about gear purchases (that is, if you and/or your wife decide you want to do that). They'll make those recommendations based on their experience and expertise. And they'll help you to develop the expertise and judgment to make good decisions and assessments for yourself.

Ultimately, yes, there are a lot of variables that you can control in this sport that can make it safer. However, it is still an inherently risky sport and you'll both have to come to your own understanding of that and whether that risk/reward is something you're willing to accept. Or not. And it's okay either way.
"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

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But it also seems that you're starting to believe that you have the knowledge & judgement to make recommendations to your wife based on what you've learned through this research. No offense intended, but you really don't.



I'm absolutely not doing this. I'm simply trying to understand the risks involved so we can make an informed decision on whether or not this is something we can justify doing (we have a son, so that naturally complicates any decision to take on an inherently risky activity).

I know we can start training at any time, and the instructors would be the best people to evaluate our abilities and recommend appropriate gear. I'm confidant we'd both complete training without much trouble, but from my perspective, that is getting the cart before the horse, because we haven't even made the decision to start yet. Understanding how different types of gear effect the chances or severity of malfunctions plays into that decision - if those high-g inducing, spinning malfunctions were just as likely to occur on low-performance gear, then I'd honestly probably pass on taking up the sport all together. So that's something I'm interested to find out before we spend a rather large amount of money on 2 sets of training and 2 sets of gear.

We've met and talked with several people locally who skydive and who also have children. The difference is that they had learned before starting families, so they got through the more risky novice stages while having comparatively less responsibilities. Since that's not the case with us, it's going to take very careful consideration before we're comfortable taking that first step towards actually pursuing the sport. I would love to just stop reading about it and sign up, we're just not at that point quite yet.

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However, it is still an inherently risky sport and you'll both have to come to your own understanding of that and whether that risk/reward is something you're willing to accept. Or not.



And that's exactly what we're trying to do.

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Chris, dont even consider buying gear yet - do the training - and if either of you decide you really love and want to do the sport, then start to look at gear. ALl the DZ's I have visited or read about provide good quality student gear. The kit should be in good condition (in UK a log book for each rig is kept and each jump logged), and the instructors really are the best to advise you on what to use in your early days. FWIW, oth my son and I are newbies, totally addicted to the sport (my son wants to go the AFF instructor route!), but we wont contemplate buying kit until we have between 50 and 75 jumps - as progression and downsizing each time incurs additional costs. Stop worrying and go experience the rush - then decide on whether you want to progress this!

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...The difference is that they had learned before starting families, so they got through the more risky novice stages while having comparatively less responsibilities...



Nope.

Check the stats.

While injury (particularly stuff like ankles and legs from bad landings) may be higher for students, many if not most deaths happen to experienced jumpers.
It's the old adage about the most dangerous time for a pilot being around 100 hours. Enough experience to think you know what your doing, not enough to realize how little you actually know.

And you don't have to spend a "rather large amount of money" right away.

Go to the DZ, hang out and watch. Ask questions. All for free.
Explain the situation and ask if you can sit through the First Jump Course. Some places will allow you to sit through some or all of the classroom part with the understanding that if you decide to continue and jump that you will pay full price.

And if the DZ won't let you do that, the FJC isn't all that much, even for the both of you.
"There are NO situations which do not call for a French Maid outfit." Lucky McSwervy

"~ya don't GET old by being weak & stupid!" - Airtwardo

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I'm simply trying to understand the risks involved so we can make an informed decision on whether or not this is something we can justify doing (we have a son, so that naturally complicates any decision to take on an inherently risky activity).



Here's a summing up of the risks - you can do everything right and still die. You can control many of the variables and skydive "conservatively", but you cannot remove all the risks.

If you're okay with that - if you've got things handled so that your son will still have a good childhood should you die tomorrow - go skydive. If you aren't, don't skydive.



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Understanding how different types of gear effect the chances or severity of malfunctions plays into that decision - if those high-g inducing, spinning malfunctions were just as likely to occur on low-performance gear, then I'd honestly probably pass on taking up the sport all together



Packing errors can cause malfunctions. Your body position on deployment can cause malfunctions. The position of the stars in relation to the planet can cause a malfunction (okay, maybe not, but that's as good an explanation as any for some of them). Malfunctions happen to even the most anal safety nazis, and it's possible that some of them could put even someone on a lightly loaded, "entry level" canopy into a fast spin.

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Certainly, conservative gear can improve your odds of survival.

Unquestionably, good training, developing good skills, and prudent judgement can dramatically improve your odds of survival.

However, sometimes that isn't enough.  A fair number of deaths in the last few years have been folks who were doing everything right... and were killed by the errors of other jumpers.  Canopy collisions can occur in a manner that the lower party never has a chance to see and avoid the diving turn coming from above and behind.

This entire thread reminds me of a jumper who thought that he was too smart to die skydiving.  He made a serious error under canopy (NOT swooping) and broke his femur.  After healing, he returned to jumping for a brief while.  During that time he told me that his crash was good for him. "It taught me that I could die in this sport."  The worry of his family, the doom and gloom in the wavier, the exhortations of his instructors.... none of that had an effect on his acknowledgement of risk.... until he crashed.  This jumper stopped jumping and sold his gear shortly after his return from his injury.

We can REDUCE risk in this sport... but we cannot eliminate it!
The choices we make have consequences, for us & for others!

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However, it is still an inherently risky sport and you'll both have to come to your own understanding of that and whether that risk/reward is something you're willing to accept. Or not.



And that's exactly what we're trying to do.



Good. But I hope you're picking up from other posts in this thread that there are a lot of ways you can die in this sport other than from malfunctions. In fact, if you look at the recent statistics (modern gear) you'll note that very few of them are due to malfunctions; a well-chosen and well-maintained system is highly reliable when used properly. (Heck, when you think about it, they're actually pretty reliable when used improperly, e.g., out-of-sequence emergency procedures, performing EPs lower than they should, etc.).

How are people dying/getting injured? Spend some time on the fatality database here and look for the themes*.

They're dying by turning low to the ground or into an obstacle. That can be on a lightly-loaded, conservative canopy, or on a highly-loaded, high-performance canopies.

They're dying through canopy collisions. That's one of those that may be your fault ... and it may not be. Either way, you could be dead.

They're dying in jump plane accidents. That's one of those where you only have so much control - if you know that a dropzone follows industry standard maintenance procedures, and that the pilots are properly trained and experienced, what happens after that is largely beyond your control (of course, jumper stupidity can contribute to or worsen an incident, but for the most part, jump plane crashes aren't due to anything a jumper or jumpers did).

They're dying because they don't pull or don't pull in time. Those are becoming increasingly rare as AAD use becomes more common, but they do still happen. Some of these are medically related, but some are jumper error. In most cases we really don't know.

There's other categories that have a few here and a few there (freefall collisions, medical issues, suicide, drowning, etc.) but those are less common.




*It's not a complete database; that probably doesn't exist anywhere, but it's pretty darn good and will give you enough information to assess. The other thing to do is to try to get a hold of old Parachutist issues that include the annual incident analysis (I believe it's usually in the April issue).
"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

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Thanks for the replies everyone, and sorry again if I'm being overly anal with all my questions. I'm not risk averse by any means, but I do tend to be very pragmatic and methodical about it. I'm just trying to gather as much information as possible so if/when I do start, I'm more able to ask the right questions and reduce the "don't know what I don't know" situation. I still don't know a hell of a lot, but at least I can begin at some level of knowledge beyond absolute zero.

wolfriverjoe, point taken about those most likely to be seriously injured. I've actually seen exactly this in scuba diving, where someone with 30 to 40 dives starts disregarding all the accepted save diving practices as not applying to them because now they're "experienced". I have upwards of 400 dives (which in itself isn't terribly high), and still follow them pretty religiously because I think drowning would be one of the more unpleasant ways to die :S

And I hadn't considered the possibility of reevaluating our comfort with the risk after training. I had been approaching it more as "I know I'm going to love it, so I need to be comfortable with all the risks before starting and be ready to purchase gear". Whether or not we love it, we can still decide it's just not for us after training. On the other hand, if we continue, we can always pay for additional instructor/coached jumps when we're on our own gear.

My focus on gear up to this point is because it's the one aspect that I can at least learn something about on my own. I think the more information I have at the point I'm sitting down with an instructor to discuss appropriate gear, the better the chances are that the recommendation will fit our ultimate desires in the sport.

Anyway, thanks again everyone.

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And I hadn't considered the possibility of reevaluating our comfort with the risk after training. I had been approaching it more as "I know I'm going to love it, so I need to be comfortable with all the risks before starting and be ready to purchase gear". Whether or not we love it, we can still decide it's just not for us after training. On the other hand, if we continue, we can always pay for additional instructor/coached jumps when we're on our own gear.



I've been in the sport for nearly 8 years (so, a lot longer than most people, but still a "tourist" by long-time skydiver standards), and I reevaluate it all the time. I don't think I'm unique. So far, reward has won out over risk, but someday it might not. That might be because some circumstance changes in my life and I'm no longer willing to take on the additional risk. It might be because I have an injury / health issue (I include aging in that) and my risk becomes greater because of that. It might be because of changes in the sport itself that would cause the "you could do everything right and still die" risk level to increase beyond an acceptable level. It could be because I just wake up one day and say "I'm done."
"There is only one basic human right, the right to do as you damn well please. And with it comes the only basic human duty, the duty to take the consequences." -P.J. O'Rourke

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