Cypres Activation Altitudes/speeds

[diverdriver 5]

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That's my impression; proof one way or another may have to wait until Hook or I can get our hands on a timed-out student cypres.

Yah, I'm sure we are wanting to see what you come up with. Unfortunate that more specific info has not been provided by Airtec. Maybe that will change now.

Chris

[Hooknswoop 19]

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That's my impression; proof one way or another may have to wait until Hook or I can get our hands on a timed-out student cypres.

I will be able to get a time-out student Cypres very soon, within 3 months or less.

Hook

[guesswhere 0]

please, for us newbies (really just me, but i want to include others to limit my own embar_ass_ment), define "timed-out student cypres"
is that after 12 years, or after one fires, or ...?

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[billvon 2,991]

> Unfortunate that more specific info has not been provided by Airtec.

I just talked to Cliff S, and he confirmed that a student cypres _does_ have two different activation altitudes. If you are below 78mph and above 29mph, the student cypres fires at a higher pressure altitude than it does in freefall.

[nacmacfeegle 0]

"define "timed-out student cypres"
is that after 12 years, or after one fires, or ...? "

I'm assuming Hook and the lads are talking about a Cypres that has outlived its design life, eg one which is older than 12 yrs and 3 months. Beyond this time period (time starts from date of first installation I believe, and runs regardless of use, etc). The cypres will still function (it just won't be guaranteed, or sufficiently reliable, it won't turn into a pumpkin or something else), its just that no rigger worth his/her salt will pack a reserve with an out of date cypres, so they are basically worthless, until we can find a use for them....

I gather Hook wants to try and fire one under severe canopy flight conditions, Billvon wants to cut one up and play with it (read torture it) in his dungeon, I want to attach one to some water weight bags and a tube.

I'm looking forward to seeing the results.

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He who receives an idea from me, receives instruction himself without lessening mine; as he who lights his taper at mine, receives light without darkening me. Thomas Jefferson

[diverdriver 5]

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> Unfortunate that more specific info has not been provided by Airtec.

I just talked to Cliff S, and he confirmed that a student cypres _does_ have two different activation altitudes. If you are below 78mph and above 29mph, the student cypres fires at a higher pressure altitude than it does in freefall.

Hmmmmmm.......then it seems you could say the same about the Expert Cypres. We all know it will fire at 1,000 feet if you snivel through that altitude after pulling low. Oh well, I think we are arguing nerd semantics at this point. The bottom line is that Cypreses are very reliable yet do have some limitations just like any other man made device. I just plan my dive to pull above "Cypres Country".

Chris

[USPA 0]

No, the expert doesn't. It has 1, 750 ft belly to earth, aprox 1000ft uncompensated.

The student has 2. (does leave my curiousity, what the real uncompensated altitude is on the second activation altitude.

The trouble with skydiving; If you stink at it and continue to jump, you'll die. If you're good at it and continue to jump, you'll see a lot of friends die...

[sducoach 0]

Bill & Chris (a.k.a. Diverdriver) Thank you for confirming my point.

The fact is that we depend upon the manufacturer to determine "burble" "low pressure" "body position" adjustments in their calculations. To speculate on their figures will create another "illusion" such as a 1300' activation in a stand up.

Fact is that if you are in a stand up at 1300' you had better hope it activates.

If in fact you deploy at 5000' and cut away, no pull to 1000' or have the same scenario you presented makes zero difference on a student cypres. It should activate at 1000' as the exception to the normal setting. But the programmed altitude is 750' with what ever adjustments for pressure altitude that is calculated. Thanks boys.

Blues,

J.E.

James 4:8

[billvon 2,991]

>If in fact you deploy at 5000' and cut away, no pull to 1000' or have
> the same scenario you presented makes zero difference on a
> student cypres. It should activate at 1000' as the exception to the
> normal setting. But the programmed altitude is 750' with what ever
> adjustments for pressure altitude that is calculated. Thanks boys.

That is correct. The one case you have to worry about is deploying low, such that you are below 78mph and above 29mph at the 'low speed' deployment altitude, which is higher than the normal deployment altitude. This effectively means you have to pull higher with a student cypres to avoid a misfire.

[skydiverek 63]

billvon

>I have always wondered - why? What's the reason for not activating below 130'?

It may be better, from a liability point of view, for the cypres to appear to be off after a fatality rather than have the cypres fire too low to save the jumper's life. Bryan Burke has claimed that, in that situation, the cypres will switch off rather than remain on; I have not verified that yet (and can't until I have a timed-out cypres to experiment on.)

1. This is one 'gossip' that I heard.

2. Second one is that Cypres disarms itself after sensing an opening, and if you cutaway after that, then it needs some time to 're-arm' itself, even though you already are at its activation altitude and speed.

3. Third one is that in case where Cypres does not fire when it should fire (lets say: freefall all the way to the ground), then it will switch itself off on impact (detecting sudden slow down from 120 mph to 0 mph in a fraction of second). The reason for the switch off would be that then one could blame the jumper on not turning the AAD on prior to the fatal jump (Cypres does not store any date and time, so it is not possibbe to conclude the last time Cypres was switched on).

Is any of these gossips/rumours (1 or 2 or 3) true?

[ChrisD 0]

Clownburner

If that's correct, the user manual is unclear, which is exactly where the source of the 'misperception' is.

Thanks for noticing this!
The user manuals are unclear,...on a number of points. IMO yo would think they could take the time to actually write better descriptions of all of their functions and their methodology in their respective manuals.

C

I mean actually write stuff down in the manuals, as compared with some sort of nebulous information that is second hand and subject to wide interpretation.

But what do I know, "I only have one tandem jump."