Vent holes in ZP canopies?

[JerryBaumchen 1,466]

Hi Bill,

Heck, the ParaCommander was considered 'crazy' by some folks.

Someone else posted, not too long ago ( DSE, I 'think' ), that it is OK to experiment but really, really think it through.

Back in late '66 I designed, tested & jumped ( what I believe to be ) the world's first AAD for a piggyback reserve container. I was a not-so-young engineering student, worked with a machinist who did a lot of the hands-on work & knew a guy who had a good background in electronics.

I bench tested and then tested it in the air ( with a 3rd canopy obviously ). It was big & bulky but I wanted to see what I could do. It worked. It might not have worked and ended up in the trashbin, that is life.

C'est la vie ( my French is a little rusty ).

Without people who can think and do, we would still be jumping 1.1's with mods cut on kitchen tables.

I wish him well and hope to hear how things go; if he does go for it.

Just my old $0.02,

JerryBaumchen

PS) As for the coffee can, you were not the only one. So many folks screwed those holes up that Para-Flite put out a 'notice' to cut on the inside of the can/template; some folks wandered a little away from the can/template on occasion.

[JohnRich 4]

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Add: "(4) It's safe." Actually, that should be #1.

It is #1. Safety is a component of performance. If it opens consistently well, flies well in turbulence, responds well to control input, lands softly, etc., we'd say it performs well. OTOH, if it isn't safe to fly, we'd say that's not very good performance.

Some people would consider "performance" to be things like the glide ratio, the swoop speed, the flare efficiency, etc. Safety is a given, that comes before all else.

[JohnRich 4]

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As for the coffee can, you were not the only one. So many folks screwed those holes up that Para-Flite put out a 'notice' to cut on the inside of the can/template; some folks wandered a little away from the can/template on occasion.

Was it actually "cutting", like with scissors or a hot knife? I was under the impression that you heated up the coffee can on a stove, then picked it up with thick gloves, and pressed it onto the fabric to melt the hole in the ribs, so the edge would be effectively hot-knifed, and there wouldn't be any fraying.

[wmw999 2,587]

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you heated up the coffee can on a stove

I never did it that way. I drew around the coffee can with a water-soluble marker and used the hot knife. The problem with the "heat up the whole coffee can" scenario would be the potential of burning something you didn't intend to deep inside a cell because you touched it to the wrong thing. Also, a coffee can might not retain heat long enough to work.

But my poor then-boyfriend, listening to me say "shit, shit" the whole time I was cross-porting his new Cruiselite . No problems, I just cussed a lot

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[JerryBaumchen 1,466]

Hi John,

I've 'heard' of the 'heat up the can' method but do not know anyone who actually did it.

When you consider the mass ( or lack thereof ) of an empty coffee can you can quickly conclude that it would not retain the heat very long; as per Wendy.

But, why not give it a try and let us know what happens.

JerryBaumchen

[billeisele 130]

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As for the coffee can, you were not the only one. So many folks screwed those holes up that Para-Flite put out a 'notice' to cut on the inside of the can/template; some folks wandered a little away from the can/template on occasion.

Was it actually "cutting", like with scissors or a hot knife? I was under the impression that you heated up the coffee can on a stove, then picked it up with thick gloves, and pressed it onto the fabric to melt the hole in the ribs, so the edge would be effectively hot-knifed, and there wouldn't be any fraying.

for a bunch of reasons that would not work, the can just happened to be the right size hole, we used a hot knife, the trick was to make the cut clean so that there would not be any big blobs of melted nylon - they would be sharp and damage other parts of the canopy

Give one city to the thugs so they can all live together. I vote for Chicago where they have strict gun laws.

[JohnRich 4]

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you heated up the coffee can on a stove

I never did it that way. I drew around the coffee can with a water-soluble marker and used the hot knife. The problem with the "heat up the whole coffee can" scenario would be the potential of burning something you didn't intend to deep inside a cell because you touched it to the wrong thing.

Well, you did have to carefully isolate the location to be melted, stretching it out over a solid surface, and keeping surrounding material away from it. Set-up was everything. You didn't want to go fishing around inside a long tube with a red-hot can.

[JerryBaumchen 1,466]

Hi John,

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You didn't want to go fishing around inside a long tube with a red-hot can.

You keep saying stuff like that and you're going to take all the fun out of 'Give me another beer & let's getter done.'

JerryBaumchen

[airtwardo 7]

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I've 'heard' of the 'heat up the can' method but do not know anyone who actually did it.

When you consider the mass ( or lack thereof ) of an empty coffee can you can quickly conclude that it would not retain the heat very long; as per Wendy.

But, why not give it a try and let us know what happens.

JerryBaumchen

Hi Jerry~

Guess I should have written an 'operation sheet'.

A yardstick with an opened up clothes hanger duct taped to it, a coffee can, leather gloves, propane torch and a phonebook...


Oh yeah, and beer!

~ If you choke a Smurf, what color does it turn? ~

[captain_stan 0]

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Some people would consider "performance" to be things like the glide ratio, the swoop speed, the flare efficiency, etc. Safety is a given, that comes before all else.

"Some people" are liable to say anything. I'm not sure what point you're trying to make here. Are you saying that a canopy's performance is not a measure of how safe it will be to use? Or that a canopy's safety cannot be measured in terms of performance?

[JohnRich 4]

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Some people would consider "performance" to be things like the glide ratio, the swoop speed, the flare efficiency, etc. Safety is a given, that comes before all else.

"Some people" are liable to say anything. I'm not sure what point you're trying to make here. Are you saying that a canopy's performance is not a measure of how safe it will be to use? Or that a canopy's safety cannot be measured in terms of performance?

I'm saying that safety is one thing, and performance is another.

A round parachute can be "high performance" (using your definition) in terms of safety, but it's very low performance (using my definition) in terms of glide ratio, swoop speed and flare efficiency. Both can be considered as safe as possible, but they are world's apart in terms of aerodynamic maneuverability and capability.

The fact that your definition of "performance" would categorize round and ram-air parachutes the same, simply because they're both safe to use, indicates that there is something amiss with your definition.

If you go around saying that round reserves are "high performance", people are going to scratch their heads and look at you like you're nuts.

Thus, I would separate the terms "safety" and "performance" into two different categories.

[JohnRich 4]

And here's another comment on your definitions, from the thread "Top 3 Reasons for a malfunction".

In message #13 you say;

"I certainly expect to have a main-canopy malfunction anytime, but believe that when it happens, it will be a result of human failure."

Then in message #17 you say;

"In all of my 1400 jumps on square canopies, I have not yet experienced a malfunction."

And finally, in message #35 you say;

"in my 600+ jumps since I've gone to elliptical mains, I've chopped 2 spinners"

So you see, on the one hand you claim you've never had a malfunction, and then admit that you've had two cut-aways due to a spinning canopy. That's got people scratching their heads, because your definitions are far different from those in common usage. A canopy that spins out of control so violently that it can't be cleared, and has to be cut-away, is a malfunction, period. To what you attribute the cause of that malfunction is another thing, but it is still, regardless of the cause, a malfunction.

To claim that every malfunction is rooted in human error, and therefore really can't be called a malfunction, is a unique theory to which I don't think anyone else subscribes. Even if it were true as you claim that every problem is due to human error, it's still a "malfunction", and we shouldn't be afraid to call it that. Avoiding the use of that word will only confuse people as to the truth.

And in your response to this, I'm sure you're going to tell me that elliptical canopies aren't square canopies, and therefore your comments were truthful. But if that's your explanation for the contradictory statements, then once again your definitions are askew.

If you want to be that picky, "square" canopies aren't really square - they're rectangular. So I could play this game and say, despite my nine reserve rides, that "I've never had a malfunction on a square canopy!" But that would be misleading, and would make me sound like Bill Clinton, playing around with words to fool people. I'm not Bill Clinton.

[captain_stan 0]

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And here's another comment on your definitions, from the thread "Top 3 Reasons for a malfunction".

Dude, pick a thread and try to stay with it.

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I'm not Bill Clinton.

Congratulations. He may be just as happy that he's not you.

[captain_stan 0]

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I'm saying that safety is one thing, and performance is another.

The FAA and canopy manufacturers disagree with you. TSO requirements refer to AS8015 (A or B), which are entitled "Minimum Performance Standards for Parachute Assemblies and Components, Personnel." If you read these documents, you'll find a set of requirements for how a parachute must perform in a variety of tests that are all related directly to safety. Drop testing is probably the most significant among these. If a canopy's "performance" does not measure up to the requirements of these "performance" tests -- if it blows up when deployed at the specified speed with the specified suspended weight, or if it has an excessive descent rate -- it will not receive TSO approval because it does not meet these "performance standards." I hope we'd all agree that the safety of such a canopy would be highly questionable. Although main canopies are not required to meet these TSO "performance standards," you can bet the the manufacturer of a main canopy has their own set of performance standards that must be met to assure that their product is safe enough to be released to the public. When we buy that product, we not only expect it to perform the task of bringing us to the ground safely, but also to have good performance in glide, flare, etc.

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A round parachute can be "high performance" (using your definition)

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If you go around saying that round reserves are "high performance"

Those are your words, not mine. I haven't used the term "high performance" in this thread, but I'm glad you mentioned the round reserve. It might not be a "high performance" canopy, but it has performed well enough to meet the FAAs "performance standards" and receive TSO approval.

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The fact that your definition of "performance" would categorize round and ram-air parachutes the same, indicates that there is something amiss with your definition.

And yet the FAA measures round and square canopies by the same set of "performance standards" [their words] for TSO approval. If either of these canopy types perform well enough to pass these tests, they are deemed safe enough for us to use.

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Thus, I would separate the terms "safety" and "performance" into two different categories.

And thus you would be at odds with most of the industrialized, English-speaking world. If a parachute must perform any task, it is to lower us safely to the ground. If it fails in the performance of that task, I'm saying it isn't safe to use, and it certainly wouldn't meet the FAA's or the manufacturer's performance standards.

[dorbie 0]

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Zippers my friend, zippers...

My Paragliding wing has VELCRO on the wing tips so you can open them up, but the main reason is to remove accumulated debris because they are inflated by cross ports only.

There is a Paragliding wing where the center 3(ish) cells can be zippered together to convert from a tandem to a solo wing.

[captain_stan 0]

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on the one hand you claim you've never had a malfunction

Your words again John, not mine. I've made a total of some 1400 jumps on square (OK rectangular or non-elliptical) canopies, and none of these has resulted in a malfunction, my point being the reliabiltiy of this design. Since my profile shows 2000 jumps (actually 2063 after yesterday's activity), I had expected that most readers could do the math and realize those 1400 jumps don't constitute the entirety of my experience. YOU EVEN COMMENTED ON THE 2000 JUMPS SHOWN IN MY PROFILE, SO HOW COULD YOU NOT KNOW THAT?! The last 600+ jumps that I've made (and 2 malfunctions) after changing to eliptical canopies, have led me to conclude that elliptical canopies are less forgiving by design.

I appologize to the readers for responding to an off-topic post like yours, and I think you'd serve them better by taking this subject back to it's appropriate thread.

[dorbie 0]

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Someone else posted, not too long ago ( DSE, I 'think' ), that it is OK to experiment but really, really think it through.

Some people shouldn't experiment.

[JerryBaumchen 1,466]

Hi Jim,

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A yardstick with an opened up clothes hanger duct taped to it, a coffee can, leather gloves, propane torch and a phonebook...


Oh yeah, and beer!

Glad to see Rube Goldberg is still alive & kicking.

Hi dorbie,

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Some people shouldn't experiment.

Absolutely! Some should not even be jumping but that is a whole different story.

JerryBaumchen

[JohnRich 4]

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If a parachute must perform any task, it is to lower us safely to the ground. If it fails in the performance of that task, I'm saying it isn't safe to use, and it certainly wouldn't meet the FAA's or the manufacturer's performance standards.

That's why I'm saying that this type of "performance" is a given, that we accept as a baseline, because it's required by the FAA. However, this is a design and testing performance standard.

When jumpers talk about the "performance" of their parachutes in the field, they're not talking about design and testing standards. They're talking about flying speed, glide ratio, flare, and other factors.

So if you're going to be this picky about the definition of performance, you should specify to which ones you're referring. Because calling all parachutes the same just because they passed the same certification process, is like calling a Volkswagen Beetle the same as a Corvette, because they both meet government standards for automobiles. But clearly, a Corvette outperforms a Beetle in acceleration, top speed, handling, and other factors. And also clearly, you're confusing people by talking about different standards, which suggest that all things are equal, when they're not.

[captain_stan 0]

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clearly, you're confusing people

Clearly, you are indeed confused, John. I'm just not convinced that this is my fault.

[JohnRich 4]

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I'm just not convinced that this is my fault.

How about this one. You started out making a statement that you have 1,600 square jumps without a malfunction. Now to just about everybody in the sport, a "square jump" is any jump on a ram-air canopy, regardless of type or design.

But if we noticed your profile data that said you had 2,000 jumps total, that means that there are 400 jumps unaccounted for. Were they round jumps back in the old days before you started jumping squares? That would be the only explanation that most people would think of, given the above assumption about square jumps.

But wait, your profile also says you've been jumping 16 years, which would mean you started in about 1993. And round parachutes were already phased out by then. So what were those other 400 jumps made with?

And then later you qualified your initial statement said that you had two cut-aways on elliptical canopies. So clearly, you must think elliptical canopies don't count as square canopies. And I think that kind of classification is way out of the mainstream of thinking.

So now at least some of those missing 400 jumps are ellipticals, but we don't know how many.

And once you start down that path of slicing and dicing different types of ram-air canopies into different categories, we have questions like these:

- What about semi-elliptical canopies - are they "square" or "elliptical"?
- What about trapezoidal parachutes like the Aqutron?
- Are cross-braced canopies yet another category?

That will confuse people. And you did it.

Just stick to the general understanding that all ram-air parachutes are called "square", and we won't get confused. The terms are synonymous!

[captain_stan 0]

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we have questions [my emphasis added]

Actually John, this far into your lengthy rhetoric, I think it's just you alone, I'm tired of trying to educate you, and I think most of the readers don't want to hear it anyway.

[fasted3 0]

Yes, please stop.
I couldn't find a phone book, and ended up using a dictionary. The coffee can burned some pages when I was cutting holes in my canopy so it would pack better. Now I am unable to follow this discussion and I can't tell who's winning.
Please no flames. I know that I am an idiot for messing up my dictionary, as it is mandatory equipment for DZcom - required for word games and hair splitting in almost every thread. I will get a new one as soon as possible.

But what do I know?

[JerryBaumchen 1,466]

Hi Cap'n,

+1 ( with emphasis )

JerryBaumchen

[Beatnik 2]

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But if we noticed your profile data that said you had 2,000 jumps total, that means that there are 400 jumps unaccounted for. Were they round jumps back in the old days before you started jumping squares? That would be the only explanation that most people would think of, given the above assumption about square jumps.

But wait, your profile also says you've been jumping 16 years, which would mean you started in about 1993. And round parachutes were already phased out by then. So what were those other 400 jumps made with?

Just an example here, I have over 400 round and triangle jumps and they were all made in this decade. Just because they are phased out for most people doesn't mean some don't still jump them for whatever reason. Just throwing that out there and not trying to side track the thread just generate some other modes of thought.