Reserves

[SkydiveMonkey 0]

Why are most (if not all) reserves made of F-111. Surely zp would be better (esp. at higher loadings that seem so common now)?
I'm not crazy - I'm a Skydiver

[billvon 2,400]

Raven dash MZ's have a topskin of ZP. However:
1. they're harder to pack, and do you really want to make life that much more difficult for your rigger?
2. new F111 is close to ZP performance. If you really need that extra few percent performance to get a decent landing, you probably need a larger reserve.
The only people I can see who might really benefit from MZ's are CRW jumpers who cut away often and need their reserves to last 50-100 jumps. ZP will last longer than F111, and give you acceptable landings for longer compared to F111.
-bill von

[polarbear 1]

F-111 is supposed to be 0-3 cfm porosity, which is "almost" like zp. The problem is the fabric opens up after a few jumps, which increases porosity. ZP doesn't do this. However, as reserves are usually not used often, the porosity issue doesn't show up much. Most reserves have a lifespan-PD reserves are good for 25 jumps or 40 repacks, then they must be porosity tested at the factory. Tempo reserves (I think) are good for only 5 jumps. I don't know about Precision reserves.
ZP is harder to pack...I have met some riggers who will not pack a zp reserve.
A jumper at my DZ looked into getting a Raven MZ, but was told that it would not fly/flare any better...the only benefit is that it lasts longer. Personally, I stick with F-111 reserves strictly for the easier packing.

[kwmontreal 0]

Bill,
Are the MZ's that much harder to pack? I just purchased one to go into a new Mirage M3 (medium fit according to Mirage). I just want to be prepaired for my riggers comments.
Jump Safe
KW

[polarbear 1]

Its basically exactly the same as the difference between packing an F-111 main vs. a ZP main. The biggest difference, as I see it, is that when packing a reserve, you are much more careful to make sure things stay in place (especially the lines). The slippery ZP might lend itself to having things slip out of place during packing, as well as the usuall difficulties of getting the air out of the canopy and getting the canopy into the bag.

[skydiverek 55]

When a canopy fabric is torn, it tends to go all the way (from nose to tail) with ZP fabric. With F-111 fabric, that is much less likely (it is gonna stop). I think it is important, taking into consideration that it is your LAST canopy.
Also, ZP pack larger comparing to F111, and that may make you downsize just to make it fit into your reserve container. Again, not a good idea, in my opinion. And, as mentioned, ZP is more difficult to pack.
Bart

[riggerrob 558]

Yes,
The slippery fabric makes Raven MZ reserves more difficult to pack.
Forget about pro-packing them over your shoulder.
If you use all the straps and clamps called for in the Talon 2 manual, you can pack a Raven MZ neatly. It will take longer because you will have to clamp it and lay weights on top of it and step back for a few minutes several times during the pack job.
Take your time if you want to pack a Raven MZ neatly.
As for the notion that ZP fabric tears worse than F-111, I rarely see huge tears in ZP fabric.

[polarbear 1]

I have heard people say in the past that zp will continue to tear under a lower force than F-111. Both fabrics are ripstop, but the coating process on the zp fabric "traps" the fibers in place, so when a tear starts, the fibers can't redistribute themselves as easily to resist the tear. In F-111, the fibers can move a little to resist the tear more.
I have seen several zp canopies with small holes in them that have not propagated or gotten larger with use. I don't usually consider the lower tear strength as a serious detractor of zp material.

[billvon 2,400]

>Its basically exactly the same as the difference between packing an F-111 main vs. a ZP main.
I would liken it more to the difference between packing a PD170 and a Silhouette of similar size. The MZ's, like the Silhouette, are only partially ZP, and not as difficult to pack as a full-ZP canopy like the Sabre.
-bill von

[weid14 0]

I believe the specs on Soar-Coat have the Zpo material with a slighly higher tear strength.... going from memory on that one though.

[polarbear 1]

Now that you mention it, I think you're right. I was just remembering what I read in the Parachute Manual about ZP-coating contributing to lower tear strength.
I do seem to recall seeing that the specs on Soar-Coat dictate a higher tear strength. I suppose there are other factors than just the coating.
billvon is right; the MZ reserves are only zp-topskin.

[councilman24 36]

ZP fabric also tends to take a "set" when packed. Some 0-3 cfm fabrics also do this, but it's random. I don't much like 0-3 cfm reserves that take a set and I wouldn't like a partial ZP that does the same thing. You can see this opening your main after our 5 month winter up here in the north. Will they open, sure. Will they open more slowly, especially at subterminal, maybe. I've got a Raven II that comes out like a brick and has to be pulled apart. Nobodies asked me to pack a partial ZP reserve yet. Don't know what I'll charge.
The reason PD reserves have a 40 pack job life is that just handling the 0-3 cfm fabric increases the permiability. I think it was the Belgium military that presented some data on this at either the 97 or 99 symposium. Off subject, they also did studies on what surface was the most damaging to parachute fabric. Worst was rough surfaced concreate, second worst was a poly tarp that we all use at boogies. The micro fibers tend to stick up and act like a wire brush. One of the best surfaces (least destructive) was smooth finish concreate that you might see in an industrial setting.

[precision 0]

The ZP fabric that we use at Precision Aerodynamics is made from Dupont Solar Max yarn and sold under the trade name Soar Coat by Performance Textiles.
All of our fabric is screened through our in house technical lab wherein we confirm testing for a number of fabric properties, including Tear Strength.
While the specification for minimum Tear Strength of ZP fabric is only three times stronger than 0-3 fabric, in reality the lab reports are always significantly greater than that minimum.
Unsubstantiated rumor and wild speculation are abundant in this area; our extensive experience (including overspeed/overweight testing to destruction) fails to support the popular rumor that ZP fabric "tends to go all the way (from nose to tail)" That is simply not true.
For detailed fabric specifications, refer to:
ExactaChute 0-3 fabric------- http://www.perftex.com/exatachute_specs.htm
SoarCoat ZP fabric----------- http://www.perftex.com/soarcoat_specs.htm