Why Cypress over others?

[fred 0]

No, not another thread about whether or not a cypress is a good idea. That debate's got whiskers.

The question I have is: Why is the Cypress AAD the most popular?

It seems to dominate the experienced jumpers scene, and is almost synonymous with AAD. But the student rigs at my DZ have FXC's. Just trying to figure out if it's a 'follow the flock' thing or if a cypress is a far superior product?

So, what are the differences between the various AAD's? What made you choose yours? Why do most people seem to choose Cypress?

[PhreeZone 15]

Cypres is a microprocessor controled unit that has proven its usefullness over time. The FXC 12000's were known for having a 1000 foot window in which it would fire. Its all mechanical so there was no way of knowing if it was broke without chamber testing it as I was told. The FXC 12000's just were not designed to be used as a reserve AAD with the altitudes most experinced people pull at. To give your self the window you set it for about 1500-2000 feet, now it can fire above that too. If its set for 2000 you better be pulling at 3500-4000 with a snively canopy to give the widest possible margin of error. They got a really bad rep years ago for causing AAD fires on people that were pulling at 2000-2500 feet. The Cypres changed this by making the window of fire much less (~50 feet) and allowing the altitude to be set at 750 feet.

The Astra is a similiar unit to a Cypres but its also made by FXC, I don't know much about it other then its mounted out side the container so you can turn it off under canopy if you want to. The Cypres is inside the container and once the rigs on you don't know who has one and who does'nt so those that feel they are'nt cool unless they jump without an AAD can still wear one and no one needs to know.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[billvon 2,442]

>so those that feel they are'nt cool unless they jump without an AAD
>can still wear one and no one needs to know.

Uh, historically that wasn't the reason. There was a time when AAD's were so unreliable that some people refused to jump with someone who had an AAD - they didn't want to funnel an exit and suddenly have a reserve in their face. The ability to hide the Cypres control unit was partly to overcome this.

[Kirils 1]

I prefer an Astra over the Cypres. Flying a high performance canopy with a Cypres puts you at risk. With the Astra I can turn the thing off once under canopy.

"Slow down! You are too young
to be moving that fast!"

Old Man Crawfish

[PhreeZone 15]

Has there ever been a documented misfire due to a HP canopy in a dive?

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[Hooknswoop 19]

Quote

I prefer an Astra over the Cypres. Flying a high performance canopy with a Cypres puts you at risk.

There is a chance of firing a Cypres at wingloadings of 3.0 or greater. I couldn't get a definitive answer out of SSK. Below that I wouldn't worry.

Hook

[packman 0]

Quote

Has there ever been a documented misfire due to a HP canopy in a dive?

what Kirils is trying to say is that with an astra is that you can turn it off after you are safely under your canopy and by doing that it totaly eliminates the worry of a misfire under a HP canopy.

"Trust your Rigger with your Life , but not your Beer or your Wife !"

[riggerrob 561]

The earlier, mechanical AADs (i.e. FXC 12000) were big, bulky and not terribly precise.
I really wish that "what's his name" would read the FXC manual before quoting inaccuracies on the internet.
If you set your FXC 12000 to fire at 1000', then you should be "saddled out" by 2500'.
The main reason that many schools still use FXC 12000s is that they are proven, older technology that works in the student environment.
Most also freely admit that they would buy Student Cypri if they could afford them, right after they pay for the engine overhaul, the hangar rental and replacing that ratty Manta in student rig #3, etc.

I am convinced that the majority of FXC "mis-fires" occurred below 2000', but users blaimed them on equipment.
As to his comment that FXC 12000s are unreliable unless chamber tested .. the last time I read the FXC manual, it said that a rigger could not legally repack a reserve containing an FXC unless he chamber tested it before every repack and sent it on a pilgrimage to its birthplace every two years.
No piece of skydiving gear is reliable if you ignore the maintenance schedule.
In contrast, Cypri contain more trustworthy electronic gizmos. In 1994, shortly after Cypri became fashionable in Southern California, three licensed jumpers arrived at my loft with scared Cypri. They all sheepishly admitted that they had been in freefall below 1000'!
There are two reasons why FXC's Astra AAD is not as popular. First, the Astra debuted a few years after Cypri were firmly established. Secondly, when Francis Xavier Chevrier brought Astra prototypes to Rigging Innovations, we told him that his Astra was better than Cypri on all but two counts. First, the control head was too big to stuff into most Cypres-ready containers. Secondly, we thought that having to shut off the Astra after every jump was more than the average skydiver could remember. If you forget to turn it off after every jump, you have to replace batteries every couple of weeks, a nuisance at best.

[PhreeZone 15]

Rob, I was told that if the device would break between repacks there ws no way of telling if it was broke, was the persone that told me this wrong? I'm not fimiliar with the inner working to know how accurate this is. I know on Cypres its got the self check on start up, does the 12000 have something similar?

I've assisted in a few chamber tests of the 12000's and they seemed to be pretty accurate to me. Within 100 feet, usually lower the device would pull the pin and need reset.

Also the reason I was using those numbers in my earlier post is thats what I was told in my FJC a few years ago.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[PhreeZone 15]

Kinda a followup question....

On the 12000's I don't know where to look to see what each level of mod did to the unit. Any one got a web resourse to point me to? I don't have a manual away from the DZ so supplements don't help much .

Part 2: On an Astra does it take anything more then a Senior Rigger ticket to mount it? Since it is outside the container is it a Mod or is it an assembly?

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[packman 0]

Quote

Part 2: On an Astra does it take anything more then a Senior Rigger ticket to mount it? Since it is outside the container is it a Mod or is it an assembly?

it would be an assembly , unless you have to do any modifications to the harness to attach it . I have never had to deal with an astra yet and dont really know anyone that even has one, most are cypres , a few fxc 12000(mainly on student gear,and a couple on exp. jumpers.)

"Trust your Rigger with your Life , but not your Beer or your Wife !"

[riggerrob 561]

Phreezone,
Yes it is possible to break an FXC between repacks and not know it.
Because the FXC 12000 is a purely mechanical device (i.e. no electronic gizmos) it is difficult to detect damage without removal and a chamber test.
The two most probable ways of damaging an FXC 12000 are dunking it in water or dropping it on concrete. However, FXCs have a long history of surviving abuse by students.
Keep in mind that it is possible to damage any piece of skydiving gear between repacks. That is why we have scheduled repacks and other inspection schedules. These scheduled inspections are educated guesses at when damage will occur.
I don't want to side track this string, just remind you that repack schedules have very little to do with opening time. Repack schedules are mainly about detecting damage before it gets bad enough to kill you.

As for the various revisions to FXC 12000s ... back in the mid 1990s, FXC came out with Revision "J". "J" incorporated a series of minor updates and changed the factory pilgrimage schedule to every 2 years. All FXC 12000s should have been updated to Revision J many years ago.
The only other revision I have seen since then is Revision "M" ,as in "M" for main. Revision M looks like J except for an additional rubber bumper on the power cable. The rubber bumper limits damage to the housing after you scare a main AAD a few hundred times. Hint, main AADs are usually set to fire much higher (i.e. 2500 feet). I have seen an FXC 12000 Revision M pull a reserve ripcord when it was supposed to.

On the question of whether an FAA Senior Rigger is allowed to assemble an Astra into a rig, it is the same standard as installing a Cypres. It depends upon whether there is any sewing involved. If the rig leaves the factory "Cypres/Astra-ready" and it is a simple slide-in installation with maybe a little hand tacking, then a Senior Rigger can do it
If there is any machine sewing involved, then the FAA considers it an "alteration" to a reserve container and you have to call in a Master Rigger.

Rob Warner
FAA Master Rigger, with SSK certification to do Cypres retrofits to old containers and the dude who did the first few Astra retrofits to Talons.

[alan 1]

FYI about the FXC

First some history:
The original FXC was developed by HI-TEK Corporation, and then further developed and produced by FXC Corporation, both out of California. Parachutes de France later produced the FXC 12000 on license from FXC Corp. The American model was found to have some weaknesses that caused it to fire when it was not supposed to. This was, among other things, caused by leaks in an air hose inside the unit. PdF has developed the unit further and improved the quality of that air hose's attachment points. In 1994 the FXC Corporation recommended that all FXC 12000s should be
updated to J-standard aka J-mod. This modification included more air filters for a "safer" and steadier inflow of air. Units that have gone through this modification have three gold colored filters on the control unit that allow air to flow into it. Only units that have been updated to J-standard have these filters.

Some data for the FXC:
Accuracy: 0-1800ft: -100ft / +300ft
1800-3500ft: -200ft / +400ft
Note: The accuracy is no longer acceptable at DZs that are at an elevation such that the firing altitude is above 3500ft. The manufacturer can calibrate the units to be appropriate for these altitudes, but
non-calibrated units will not be.

Firing parameters: None at speeds below 40ft/sec
Possible at speeds above 40ft/sec
Effective at speeds above 65ft/sec

Altitude setting/re-cocking:
The manufacturer recommends that the main canopy is deployed at least 1500ft above the set firing altitude for the unit. The jumper should be
under a fully opened canopy at least 1000ft above the set firing altitude. This is done to allow the pressure within the two internal chambers to equalize with the outside pressure before reaching the set firing altitude. If the chambers don't have time to equalize before the set firing altitude the right chamber will have a higher pressure than
the left one as an air hose inside opens.
When this occurs a membrane will either move enough to cause the unit to fire, or just enough for the locking pins to move slightly, which can cause a misfire on later jumps. The same can to a certain degree happen if the jumper engages in "sharp"
turns while under canopy. The FXC must be re-cocked if there is a suspicion of a "near-fire". It is
not enough to just recalibrate it. To re-cock the unit it must be removed from the rig! The unit should be in JUMP mode while doing this. To re-cock the unit you need to place a round screwdriver, or a designated "loop" through the eye at the end of the release cable. Stand on the screwdriver, or the "loop" and pull the main unit straight up. Do not
pull on the cablehousing or the airhose. Pull it steadily until it stops and hold it there for a few seconds. Do not pull too hard, or after the cable has been pulled to its outer position, as this can cause damage to the triangle spring, which controls the release mechanism. Release gently until it stops.

Calibrating the unit:
Always make sure the unit is set in the JUMP position before calibarting it. On earlier models it was necessary to take up any slack that was present
inside the control unit when setting the altitude. This was done by first setting it to 4 (4000ft) and then go back down to 1 (1000ft). This should not be necessary on models with the J-mod (FXC says it's not necessary), but there's no harm in doing it.
Make sure that the needle is directly above the 1-line. There's a small gap between the needle and the dial-face, so one could be fooled a little by the shadow effect that is created. After the unit has been calibrated for the day it is not necessary to do
anything with it unless the air pressure has changed "significantly" (i.e. the needle has moved noticeable from the original position) or the unit has been turned off. The unit should always be in the JUMP position. This even includes when shipping the unit. It should only be set in the OFF position for short periods of time, which include going back down with the plane, landing in water, landing in deep snow, or before the trunk of a car is slammed shut
with the unit inside it. The reason for this is that a membrane/seal that closes the valve for the
air hose can be deformed because it remains closely pressed against the valve opening. This deformation can influence the firing altitude, as the
membrane/seal does not close the valve sufficiently during regular use. In other words, turning the unit OFF and leaving it that way for a long
period of time can increase the chances of the unit misfiring.

Finally, the unit should stay at least 15 minutes in the outside temperature before calibrating it, to make sure that all its components have reached the same temperature. Failing to do this could lead to a
wrong setting, as changes in temperature could cause movements within the materials.

These are basic things to do to prevent misfires. Chances are the people who are worried about FXCs have heard horror stories, or urban legends about earlier models of the FXC, or about FXCs that have not been calibrated correctly, or been maintained
properly. There are a lot of small things that people don't know about, which can all cause the unit to fire prematurely.

alan

[BlindBrick 0]

Quote

Cypres is a microprocessor controled unit that has proven its usefullness over time. The FXC 12000's were known for having a 1000 foot window in which it would fire

Me and my buddy split the rigging duties for student gear at our dropzone. We exclusively the J mod FXC's 12000's. We are required by FXC(and by extension, law) to chamber test the units every repack cycle. Everyone of our units fires with the /300/ foot tolerance that FXC finds acceptable. In truth, all but one of our units fires within /100/ feet of the set altitude. The one unit that fires within 300 feet is one we use as a teaching aid for our first-time jump students. 13 /years/ out of date and with damage to the face and casing of the control unit, the thing still operates within factory specs.

As a student AAD, the FXC 12000 is a very good choice. They are cheap, reliable, and it is a lot cheaper to return one to service after it fires. With a Cypress or an Astra, you have to replace the cutter at ~$150 US. With a 12000, you simply get a hook and recock it, cost: nada.

The only real drawback to an FXC 12000 for an expereienced jumper is the stigma attached to having an AAD that is that old, bulky, and mechanical. There has been some talk about two-out situations caused by FXC's. But this isn't really an issue with the mod J's. With their narrower operating range, you can set the activation point on a mod J down to a 1000 ft. and get performance similar to an Astra without having to worry about batteries or cutters.

As for the Cypres vs. the Astra, it's a close call. I have heard that FXC came up with a mod that conserves the battery by shutting the unit down after a set time in case you forget to turn it off. If that's true, I'd personally go with the Astra as it's the more rugged design and with a $60 test kit from FXC, your rigger can perform checks that keep you from having to send your AAD back to the factory for those expensive "4 year" checks.

-Blind

"If you end up in an alligator's jaws, naked, you probably did something to deserve it."

[billvon 2,442]

>As for the Cypres vs. the Astra, it's a close call.

The Cypres contains software that reduces the chance of a misfire; the Astra does not. Early Astras misfired pretty often. To fix the problem, rather than add sanity checking, FXC upped the speed threshold. Based on that I'd choose a Cypres over an FXC.