Raven ZP reserves

[askir 0]

Hey I am trying to pack a reserve with zero P top skin and I know there has to be a better way, does anyone have tips, suggestions, experience?

LIFE IS LIKE A CIGARETTE, YOU CAN SIT THERE AND WATCH IT BURN AWAY OR YOU CAN SMOKE THAT BITCH TO THE FILTER

[MrHixxx 0]

I asked the folks at Performance Designs some time back about ZP reserves. I think you will find their following reply interesting...

-Hixxx



Why don't we use ZP fabric in our reserves?

First, the tear strengths listed in the specs are very misleading, for
two reasons. The tear strength is measured at a specific tearing speed,
measured as a certain distance per unit of time. When you tear things
relatively slowly, the tear strengths are quite high. However, when you
increase the speed of the tearing motion, the actual forces required to
keep the tearing motion progressing actually go down. The tear spec is
measured at a standard 12 inches per minute, a rate at which the ZP
fabric looks superior to the standard fabric. However, this tear speed is
not very realistic compared to the way a canopy would really tear.

Because of this, we have created our own testing machinery that can
measure tear strengths at up to 150" per SECOND. When you measure the tear
strength at a high tearing speed more like what would happen in
reality, the tear strengths go way down, to the 3 to 7 pound range. The
standard fabric actually has a higher tear strength at these speeds than the
ZP fabric torn at the same speed.

So to cut it short, the tear strength of the ZP fabric is lower than
that for the F-111 style fabric when the tear speeds are up where things
would be in an actual failure mode.

When a ZP canopy fails, it is typically pretty catastrophic, with tears
going every which way in unusual patterns. On F-111 type canopies, the
damage is typically more localized.

Other reasons to not use the fabric? The benefit of ZP fabric is
partially the fact that is stays low porosity. If that is an issue on your
reserve, you are using it way too much. Another benefit is the presumed
aerodynamic advantage. In reality, the aerodynamic performance is due
to other aerodynamic issues such as better airfoils, aspect ratios,
trim, etc. These items aren't suitable for reserve designs, due to opening
issues. When you use good reserve aerodynamics, but throw the ZP fabric
in there, you don't really get an improvement in landing performance.
An example of this can be seen by comparing the ZP lightning crew canopy
to a ZP Spectre. The two canopies are designed to do separate things.
The Lightning lands well for a CRW canopy, but is relatively tricky to
land compared to the Spectre, even though both canopies have ZP fabric.

.

[precision 0]

Quote

tear strength [of ZP] at a high tearing speed ...go way down, to the 3 to 7 pound range

The standard for tear strength in 0-3 fabric is even less at only 5 lbs.
http://www.perftex.com/exatachute_specs.htm


The standard for tear strength in ZP fabric is 15 lbs.
http://www.perftex.com/soarcoat_specs.htm

The experts in the fabric industry have been tearing parachute fabric for more than 50 years. Nobody is pretending that parachutes ever tear slowly. All parachutes tear fast, once a tear is initiated.

It is the Tensile Strength (47 lbs) that discourages tears from initiating. The Tensile Strength is exactly the same for both ZP and 0-3.

If you want to get correct answers about parachute fabric, ask a fabric expert, not a canopy manufacturer.

[MrHixxx 0]

If you want to get correct answers about parachute fabric, ask a fabric expert, not a canopy manufacturer.

Quote

But you are a canopy manufacturer???
My understanding is that was the admitted limitation of Performance Textiles testing and that is why they developed their own equipment to better assimilate a canopy failure. They don't have anything to profit from slamming a your and their material vendor. Seems like valuable info to me. Just like new reserves with Spectra tape and continuous line attachment points that go all the way up the ribs. That is a valuable innovation. I want your reserve product to save my ass more than perform. I have a Xaos for performance.

It is the Tensile Strength (47 lbs.) that discourages tears from initiating. The Tensile Strength is exactly the same for both ZP and 0-3.
***
Once damage occurs though, don't you have a better chance of it being less catastrophic with 0-3? That being the case I would think it is a no-brainer since the reserve is a life preserver more than swoop machine... As a customer, if there is even the slightest difference in the resiliency of the fabrics, I want the tuffer stuff. Aren't the new R-max reserves all 0-3 cfm fabric?

respectfully, Jon

[askir 0]

OK may be I wasn't clear: I am a new rigger and I have come accross a couple ov Raven MZ, which have ZP top skin, I am looking for advise on tecchnique for packing these things as they pose a bit of challenge
Thanks

LIFE IS LIKE A CIGARETTE, YOU CAN SIT THERE AND WATCH IT BURN AWAY OR YOU CAN SMOKE THAT BITCH TO THE FILTER

[riggerrob 643]

When packing ZP reserves, use all your clamps, molar straps and a healthy dose of patience.

Try the clamping techniques explained in Rigging Innovations Talon 2 packing manual.

www.rigginginnovations/etc.

Packing ZP reserves requires an extra 20 minutes, but fortunately most of that extra time is spent sitting on the canopy waiting for air to squeeze out.

[cssriggers 0]

We like to get them all ready to bag, then go nuts weighting them down. Then we go off and work on something else before coming back to bag and close.

By this I mean get it all flaked out down on the floor, narrowing folds (more narrow than a usual reserve helps,) clamp the folds well, then put weights over the entire canopy. When I first started packing MZs I would weight them overnight .. then they would be quite docile going into the bag. In any case, be slow and careful and keep control of the canopy.

It also helps to have good climate control in your loft. Packing an MZ in a cool, dry environment could be challenging. I imagine they're no fun if you're sweating either.

If you normally don't use a molar strap, I wouldn't start using one with an MZ ... but that's just my opinion. Good luck!

Alpha Mike Foxtrot,
JHL