New Canopy - Sub-terminal or Terminal First Use?

[brettski74 0]

  Quote

You should be a test jumper with that kind of thinking. Having less variables in a equation is always a better option IMHO. The opening/inflation of a parachute is a very violent process in reality. The forces will be higher there than any other time. After that the stress on the parachute components is pretty low and very unlikely that something would happen. Sure it is possible but very unlikely. The materials used in the construction can be pretty resilient and usually can survive many low stress openings and flights prior to breaking/failing, whereas the same cannot be said for high stress situations. This is just my experience talking and the few hundred test jumps I have done.

Don't get me wrong - I'm aware of some of your achievements with vintage gear and I respect your opinion, but I believe you have misinterpreted my post. Take a look at the last line of my post again. I'm saying *I* don't know. There are only 3 riggers who have posted in this thread. They don't all agree. There is also lack of consensus among skydivers of varying experience levels. With no clear consensus and no experimental data for me to review, I don't know what the correct answer is, but I also don't believe it's as simple as big shock == incident, small shock == all clear. Components *have* failed on final approach and landing, so while most malfunctions do occur during or near deployment, it's not the only possibility and the recoverability of a malfunction at 400' vs 4000' makes it a more complicated risk equation.

I don't know, so I'll take the recommendation of the people who designed the canopy and the manufacturing processes that built it, because I'm fairly sure that they will have at least done some testing and may have a better experimental basis for their position.

[billvon 3,072]

>I have heard a couple of differing opinions on how to treat a brand
>new canopy on first jump.

Jump it however you plan to use it.

The only time I've not wanted to take a canopy to terminal on its "first" jump is when I've made intentional modifications (different line trims, slider changes etc) and didn't want to risk a very hard opening.

[billvon 3,072]

>The only problem is that when force is applied, like on opening shock, it
>can slip right out from under the stitching.

I've noticed the opposite. We had a Velocity that was missing stitching on a fingertrap; it deployed and flew with no problem but fell apart during packing. I've also seen incidents where a jumper forgets to knot or sew the toggles, and the fingertrap holds until he lands, then falls out. (You can test this for yourself with a few pieces of Spectra and a fingertrap tool.)

The risk there is that it slips _almost_ all the way out after it's unloaded, and then has insufficient inserted length remaining to stand up to the next opening.

[Beatnik 2]

Fair enough. I may have misinterpreted your post and I apologize for that. I know many know me for a lot of my vintage gear jumps but I have done a lot of modern test jumps as well. Unfortunately I can't talk about those as freely as I would like. One of the things you have to be aware of with riggers and their opinions is that there are many that really don't know a lot more than packing reserves. Some get it in there head that because they have a rigger rating that they know everything about parachutes.

I won't give any other advise that want you mentioned last about taking the recommendation of that manufacturer. But I would say to fully inspect the canopy before making a jump on it. I have had to send brand new equipment back because things were missed in the quality control checks. May personal opinion is to fully inspect and then do a high hop 'n' pop. Then that gives you plenty of opportunity to check out the canopy. Thats what I do when I get hired by a company to test something and so far no one has complained or suggested that I take anything to terminal on the first jump.

[fcajump 164]

As one of the riggers who has learned that I don't know everything, but want to...

I personally agree with Beatnik in that a full inspection first goes along way.

But I still do a sub-terminal the first time on a new canopy for several reasons:
- high pull to learn the canopy
- less likely to get slammed (or be slammed less) by an ill-behaved/trimmed/cut/sewn canopy
- IF there is something wrong with the canopy that can fail while sub-terminal, I'd rather find that on a sub-terminal jump.

I take several jumps to get the feel of a new (to me) canopy with increasing delays and speeds.

Side note - even two canopies of the same make/model can open/fly different (especially if older).

As to the idea of using sub-terminal jumps to "set" the canopy... I've heard of it and the explanation I got was that by putting higher loads on it through a series of jumps, the fibers would set more gradually. Whereas taking it from completely loose to a full terminal opening might damage the fibers (longer motion all at once = more heat = more fiber damage).

It was not indicated that this would fail the canopy, just shorten the life of the canopy/lines...

How true, dunno. Still true with modern materials? Dunno. That was back when line replacement was because one broke ("trim" that's what you did to the end of a line that was too long) Now most canopies are relined before anything breaks.

So... sub-terminal to "set"... maybe not so much. But there are other reasons to start sub-terminal.

Just the $.02 of a 20 year student on this stuff... JW

Always remember that some clouds are harder than others...