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Quagmirian

My little project

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Quagmirian

Thanks for the kind words everyone. I'd still like to do a few more jumps on this prototype. Speaking of the next canopy however, does anybody know where a sensible place for the bridle attachment is? I put mine between the B and C lines, and there were concerns that this is too far forward. Thoughts?



I think the main concern is only the ribs and cross ports inside. As soon as it begins inflation the canopy itself should take up the drag and become unloaded at that point. I have found the cross port idea that John Sherman answered in my other post about to be "interesting". It would be a point to look and see how much rib deformation there is.

-Michael

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Is anybody on here intimately familiar with fabric strength testing? The reason I ask, is that I bought a roll of sub strength fabric which doesn't meet the European PN1 spec of 400N/50mm, but apparently does meet MIL-C-44378 (46lbs/inch). A quick conversion shows that the American test is higher, so what's the difference?

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25 years ago, every rigger understood the finer points of tensile-testing canopy fabric and had the proper tools to do the job correctly.
That was back during the acid mesh era. For a while, Performance Designs also insisted on tensile-testing their reserves.
Thankfully those days are behind us now, but you should still be able to find a grumpy, old, grey-bearded, Master Rigger who has a set of tensile-testing clamps. Hint, they look like Vise-Grips, with fancy square jaws and rubber padding. The best way to learn how to tensile-test fabric is with that grumpy, old, grey-bearded, Master Rigger looking over your shoulder.
All the other learning methods are more expensive!
Hah!
Hah!

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Their's actually a lot more to QC on fabric then that one tensile test. For example I was once talking to Chafen about his testing. Another test he felt strongly about was tear strength. He would take a long strip of fabric several inches wide and start a cut up the middle. He would then put the two halves in clamps in a machine that pulled them apart at a set rate tearing the fabric down the strip, measuring the force along the way. He argued that he wasn't as interested in how strong the fabric was but in how weak it was. That the failure point told him more about it then an idealized tensile test under ideal conditions. This plays into how tight the weave is, how slippery/lubricated the coating was, how stable the fabric is. Example, If a fabric is heavily calendered then it's almost fused together. The fibers can not shift relative to each other. It's almost like plastic. It can have a very low tear strength even though the tensile strength can still be fairly high.

The thing to do is call up one of the mills and see if they will explane the standards to you. They can probable send you a link to them but it may take some explanation. In the mean time I'm guessing that it would probable be good enough for a prototype. Keep in mind how long some canopies have been in service and that the lines and fabric all deteriorate from wear and tear, UV, sweat, etc. over time. I don't think you've got 1000 jumps on any of your prototypes yet so this fabric is probable a good deal for you.

I was talking to the Performance Textiles guy at PIA. I had not realized that they had been bought out by Brand and Oppenheimer and are now one of their divisions. Contact...

Wendy Staley
Customer Service Manager
wendy@brandandoppenheimer.com
336 275 5800

I spoke to a guy but I wound up with this card. I'm sure they can point you the right way but be ready for a long lecture or a lot of reading if you really want to understand the specs.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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If the canopy is reinforced correctly you can get away some pretty weak fabric. At Para-Flite we had our own testing standards that made weak fabric showup easier. We sometimes used weak fabric for proto-types that we knew would not get too many jumps on them.

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accumack

We sometimes used weak fabric for proto-types that we knew would not get too many jumps on them.

Heh heh, now there's an answer I was subtly hoping for.

I haven't stopped thinking about what I'm going to do next, in fact I've started work on the next canopy. I'm in no rush however, since I still need to get used to my first clutch motor machine and all its differences. I also want to do lots more jumps on my lovely grey canopy.

[inline machine_small.jpg]

I've already made a slider for the next canopy, using my single needle.

[inline slider_small.jpg]

This thread is dragging on a bit now, and I'm supposed to be writing a few articles about all this. Is there anybody who would want to read more as I continue? Maybe a blog or something? That way I can stay in contact, and put this thread to rest.

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Please keep this THREAD going.
The most important parts are sharing your "lessons learned" with junior sewers and riggers.
You are struggling with "work arounds" that grumpy, old, grey-bearded Master Riggers learned decades ago. Please share your "work arounds" with every one.

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RiggerLee

...from what little I see you don't seem to have a good grasp of the back ground nessasary to do it.



Funny, I have a friend that designed and built his own canopy when he had 40 jumps with no education in aeronautics of any kind. He borrowed my PD Excalibur, took measurements all over it, and proceeded to build an improved version call The Stealth. 27-cell design.

Early testing was done by tethering it to the back of a pickup truck and opening characteristics were tweaked through a series of hop n pops test jumps. After that he took it to terminal and continued jumping it for several hundred skydives.
Chuck Akers
D-10855
Houston, TX

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Quote

This thread is dragging on a bit now, and I'm supposed to be writing a few articles about all this. Is there anybody who would want to read more as I continue? Maybe a blog or something? That way I can stay in contact, and put this thread to rest.



No reason it has to be an either/or type situation. you could always do a proper blog and update this thread with a brief summary and a link to the relevant post.

Having this thread as a canonical resource would also have value, though I could also see the point of view that "my little project" has been finished and you're on to "my other little project"

Either way I'd follow along to wherever you post new info as it has been a great read

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One thing to consider is which format will be around longer. I went back to a car forum last year to check on some ideas for my 2004 subaru, and a lot of the older posts had links that were broken.

Websites reformat occasionally, or they just sometimes shutdown. This place has been here for a long time, so keeping pictures and posts directly on the site is a good way to ensure they will be around for a while. (unless you get too many posts. so don't start a rumor that db cooper built his own parachute).
It's flare not flair, brakes not breaks, bridle not bridal, "could NOT care less" not "could care less".

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Well shit. What follows is a rant.

I'm not allowed to jump my canopy, nor is anybody, for at least the next two months. I'm sure a lot of people reading this thread will be just a pissed off to hear this as I am.

The whole thing started because we went to the riggers meeting to ask permission to jump the canopy I had built. But the way we had asked it meant that my CCI wasn't sure whether we still needed a cutaway rig or not. Fast forward to about a month ago and I had already jumped my canopy in California. We went to the Safety and Training Committee to get final confirmation that I would be alright using it as my main. What followed when the subject was brought up was some of the finest grade-A bureaucratic bullshit I have heard in my life. I do know a lot of the people who voted, and skydiving is a small world, so I won't talk too much shit or name any names. They may even see this thread. I will list some of my favourite reasons that were given:

-Mains have to be TSO'd
-Manufacturers must be insured (UPT anyone?)
-The BPA is not insured for home built mains
-I am not qualified to be doing 'test jumping', even after having someone else do the first jumps
-The canopy may suddenly collapse
-I don't know what I'm doing
-I have no quality control to show

The worst part about this is that many people wished me luck and said they did not want to stifle my project, but then went on to vote against.

We will obviously have to come up with a new plan of attack. I may also regret posting this while angry.

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Hi Quag,

Quote

I'm not allowed to jump my canopy



Is this the BPA imposing this?

Re: Mains have to be TSO'd

Do they require this for factory-built mains?

Re: Manufacturers must be insured (UPT anyone?)

I know of not one here in the USA that is. That is why more than one company has used 'The Not Insured * * *' in their official company name.

Re: The BPA is not insured for home built mains

Do they have insurance for factory-built mains?

Re: I am not qualified to be doing 'test jumping', even after having someone else do the first jumps

Are the 'qualified' attributes listed somewhere? That I would like to see.

Re: The canopy may suddenly collapse

And Chicken Little told us that the sky was falling.

Re: I don't know what I'm doing

The proof of the pudding is in the eating. I think that is an old British saying. Well, you did build it; and it did work.

Re: I have no quality control to show

Anyone who thinks this is the 'save all' has not worked in the quality control business.

STRANGE, VERY STRANGE. A true Kafka-esque comedy.

But, I wish you the best of luck.

Jerry Baumchen

PS) One of the books in my bookcase is a biography of Joseph Stalin. In it, it says that Great Britain was the 2nd-most regulated country in the world at the end of World War II. Looks like little has changed.

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Yup, classic Nanny State. BPA is the worst for this kind of nonsense. But you should have know the outcome of going to a committee with it. It's all about their power, nothing else matters, nothing else ever will.

You should have just kept it on the qt.
Always remember the brave children who died defending your right to bear arms. Freedom is not free.

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Well, shit is right. You said for the next two months, I'm guessing that's when the next meeting that you might make an appeal at is scheduled. Did any one point out to them that that pretty much consttutes your entire season their in England. I'm just guessing at that. All I remember of my trip their is low clouds, rain, and sleeping on the side walk in front of the train station waiting for the next boat headed for Norway. But their is a solution. Road trip. Come hang out for the summer in the US and fuck those guys. Get a job packing. Live cheep on the hanger floor. Eat Rommen off a camp stove. And spend the next two months making 100 test jumps on your canopy. While your at it start documenting your testing.

Do you have the recetes from your project? Call up your suppliers and ask them for a copy and paper work from the lots on those materials. It's easier to do up front. But they keep it forever so it's their even if you didn't request it before. Start your materials tracking files. Should have done that before. It's just a file cabinet where you keep the paper they send you and a tag or stamp on the roll. It's not that hard if it's a natural part of the receiving process when UPS delivers to you.

Buy one or two of those data recorders that I sent you the link to. Their not that pricey and It gives good "pretty" graphs and things to populate your records with. Passes the "Weigh Test". Paper work must out weigh the airframe before it can be certified. Not that hard since a canopy only weighs about 8 lb. Nice thick report. Hell bring it here. The people over at temple will love having you their for the summer.

Look at Jerry's post. He nailed it. Send them a written formal request asking for a formal answer to each of those questions. Ask them for a written reference citing the specific regulation on each of those points.

It's England so I don't know these answers.

Do mains have to be TSO'd? That's a US term and their is no US TSO for mains. Ask to see the TSO that was provided for Performance Design canopies. Ask for a copy of the regulations and process to obtain this TSO. Ask for it in writing.

Insured? If that's the case then obviously proof of this must have been provided to them by every manufacturer including PD. May I see that please? In writing please. And send me a copy because we would all like to know what company will right a rider on parachute equipment.

BPA is not insured for home built mains. I would take exception to that. The home built part. Go file a DBA, Doing Business As, That's what we would call it here. And hang a hand painted shingle on your door. Wayper Enterprises. And add a guy giving a big raspberry to your logo. It is now your factory. You are a business. As to the other half of that statement. By extension that means that they are required to carry insurance on every manufacturer licensed to be sold in Britten. I their for require them to show proof of insurance for every canopy sold in Britten, in writing please. Notarized copies will do nicely.

You are not qualified to do test jumping. This may be the case. Please produce a copy of the written regulations covering this. You may have to hire a test jumper for your development program. I'll bet I qualify. And since you are the manufacturer you decide how long phase 1 of your testing program should last and when it is successfully completed, ie. it will be successfully completed by the end of your summer trip to Texas. Once your past phase one and no longer require a cutaway rig then the regulation on who can do an intentional cutaway are moot. PD has hundreds of test jumper of all levels so that they can get feed back from jumpers all across the sport.

Canopies may suddenly collapse. True. Every one. Let's see how many cases of canopy collapse we can name starting with PD. I can think of dozens in all kinds of conditions. Hand them a file an inch thick and ask them if they are going to ground all of these canopies. And please note that their are no cases of your canopies collapsing.

You don't know what you are doing. Prepare a presentation on your design including all of your spread sheets, QC program, patterns, trims, reams of raw data dumps from the data recorders on your jumps over the summer on your road trip. If you really squeeze it down you can probable keep it under two hours. That's about the bladder limit on most people. Exactly how many of them have designed, built, tested, and jumped their own canopy. Please ask for a show of hands at the next meeting. Submit that these individuals are the only ones competent to vote on this issue. I would have no fear of the out come of that vote following your presentation.

QC. Already covered that. Not to rub it in but I told you that you needed to keep more complete records of your designs, changes, trims, every test flight or jump, materials tracking etc. Now you're stuck kind of playing catch up. If you generate this paper along the way it's not that hard. And that data is invaluable. It's a reference for all future work. If your not keeping records then it's not testing. It's just jerking off. PD has a written report for every test jump ever made with model, version, trim, slider, break setting, altitude, delay, airspeed, what was done, and a detailed report from the jumper on every part of the jump. If you ever make it by PD ask to see the files on say the velocity. This would be easier if you had a big three ring binder full of the record of this canopy. The book of the "Gray Thing".

So for most of this my point is Bureaucracy works both ways. If they want to play those games. Learn to play and beat then to death with it. Would you like to see the paper work for a launch approval through the FAA, White Sands Missile Range, and NORAD? It does out weigh the air frame. And the air frame is over 1000 lb. dry.

So take the summer off, be a drop zone bum, jump the shit out of your canopy, clean up your paperwork, and come back at the end of the summer and drop a nuclear bomb of reports in their lap.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Heh, I knew I would get you all on my side.:)
Paper trail is where I will put my hands up. I will start collecting all the receipts and invoices and write down all the batch and material numbers somewhere.

As far as I'm concerned, testing finished before I first jumped the canopy. I've only got 100 jumps, I'm not a test jumper. I'm just evaluating the canopy now, looking for wear patterns and such.

Next meeting we will probably be submitting a test plan for the canopy. Here's a list of all the manoeuvres we've done on the canopy, in order. If anybody wants to suggest some more, it'll be good filler for the test plan.

3 second delay
Rear riser turn with brakes set
Rear riser stall with brakes set
Brakes released to full flight -note surge
Full brakes
Wraps as necessary to full toggle stall
Stall recovery -note surge
Double front risers
Single front riser turn
Rear riser turn in full flight
Rear riser stall in full flight
Spastic rear riser input
Toggle turns
Flat toggle turns
Toggle flare for landing

Rear riser stall with sudden recovery
1 full voluntary line twist with rear riser input
Rear riser flare for landing

5 second delay
Rear riser 'helicopter' spins
Accelerated landing

8 second delay
Deep brake approach

10 second delay

15 second delay

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(Edit: What I'm saying is admittedly similar in tone to what Baumchen and Lee have said but reinforces the point:)

Are there any British canopy manufacturers?? I mean, are all sorts of other people in the UK pumping out quality canopies, or are you the only one to build one in the last 5 years?

If being snarky with the BPA, instead of coming up with reams of data for them, challenge them first, to come up with all the lists: What are their test pilot qualifications? What are their canopy quality control checkoffs? What list of maneuvers or testing must be accomplished to 'qualify' a main canopy?

So while the BPA has a bunch of rules on all sorts of stuff, do they actually have standards in this case or just a vague feeling of unease?

If they can't just go print off Form #XB258-1 or whatever with the required information, they don't have shit to say about canopy testing.

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Quagmirian

The whole thing started because we went to the riggers meeting to ask permission to jump the canopy I had built.


A wise guy once told me that begging for forgiveness works better than asking for permission! That worked fine for me for the last 15 or so years. Something to think about for the next time!

At the last PIA symposium a friend told me that BPA actually stands for " Ban Parachuting Altogether" B|
"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

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pchapman


(Edit: What I'm saying is admittedly similar in tone to what Baumchen and Lee have said but reinforces the point:)

Are there any British canopy manufacturers?? I mean, are all sorts of other people in the UK pumping out quality canopies, or are you the only one to build one in the last 5 years?

There are no British canopy manufacturers, and now we possibly know why.

Quote

If being snarky with the BPA, instead of coming up with reams of data for them, challenge them first, to come up with all the lists: What are their test pilot qualifications? What are their canopy quality control checkoffs? What list of maneuvers or testing must be accomplished to 'qualify' a main canopy?

So while the BPA has a bunch of rules on all sorts of stuff, do they actually have standards in this case or just a vague feeling of unease?

If they can't just go print off Form #XB258-1 or whatever with the required information, they don't have shit to say about canopy testing.

This is the problem. The BPA does not exist to police equipment manufacturing. And yet the seem to think that. They have no guidelines, no standards, no nothing. All they have is this:

Ops manual

1.2. Parachutes may only be used if they are manufactured for Sport Parachutists or
Military Parachutists, by recognised parachute equipment manufacturers or riggers
with the necessary qualifications.

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Maybe you know this, but that now reminds me about Dick Gays and his amazing Slots and Parashapes canopies in England in the 80s:

He mentions in http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=3776189#3776189 that
Quote

At the time the British Parachute Association required all parachutists to wear two parachutes made by "an approved manufacturer”. As I was not an approved manufacturer, not a rigger but just a Do It Yourself bloke, for quite some time I had to use whatever I was testing as a third canopy in a cut away rig.


(Also see another post of his a little earlier in that thread.)

I don't know if the rules were different then, or he stretched the definition of "parachute", but he got away with jumping and landing experimental parachutes that way. As you'll see in his photos, he made the cover of BPA's magazine. Anyway, you can ask the BPA how they handled his case.

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