Basejumper.com - archive

 

Hey, I wouldn't want to judge the condition of gear through the internet but I have a Mojo 280 that has probably 200 jumps on it now, DOM 2000 with the original lineset. There is a lot of experience within skydiving when it comes to judging the condition of gear, might be an idea to ask a couple of reputable riggers their opinion. Bear in mind this canopy is your only chance once you step off...
Good luck!

 

Cool. I've heard anything between 250-400 jumps is a reasonable estimate for canopy life in terms of jumps, although some have lasted much longer with good care, indoor packing, nights jumps etc (~500+ jumps) Haven't heard of BASE canopies being retired due to age alone without a significant number of jumps, but that's just me.

I guess my main concern had to do with violent openings and whether or not the stiching between cells gets brittle after age, especially if the canopy has been water landed before. I've never heard of these type of tears but I guess I'm just paranoid and trying to get information from a bunch of different sources before I trust such a good deal. Thanks for replying so fast.

Climbing rope or gear is more apt to exhibit "single point" or "catastrophic" failure rather than an accumulation of smaller failures from wear and tear. Keep an eye on your canopy's general condition and flying characteristics. If you start getting lots of random stress tears and line breakage or it starts to drop you in like a sack of potatoes it's time to consider retirement.

Just like a fabric covered aircraft there is no hard and fast criteria for when to retire the covering. It's about general condition. Like replacing trigger wires on a cam you can reline a good canopy to extend it's life substantially. Knowing whether it has been abused may or may not be evident in a rope or cam but is not too hard to tell with a canopy by it's performance and whether it starts to fall apart prematurely.

jon

You can always send it to someone who has one of those fancy machines that tell you how many jumps are on it.

Also, if it surges forward really fast on opening I would think about getting another one.

something fishy about a canopy that needed to be relined after 25 (or 50 depending on how I understand you) jumps.

otherwise - 8 year old canopy won't be degraded by age - rather by how it was stored, jumped and treated.

I have a 2001 BlackJack that I have never thought twice about jumping - both terminal and low SLs - as well as a recent jump on a 1996 MOJO with a few patches and water/tree landings.

IF in doubt - get it checked out by a knowledgeable rigger.

 
It's good you're asking some of these questions. There are some things you can check. I'll try to give you the cliff notes but under stand that this is a subject of debate and you're going to have to dig a little deeper then depending on just one sorce or looking up one post to find the inscribed word of god. I don't know you or your back ground so please for give me if i sound a little pattranising. Baseically this is rigger shit. As you become more expereanced as a base jumper you will become a rigger if not in name then in practice. As he said you can also draw exampals and presidents from the FAR's on fabric aircraft and balloons on UV dammage and life span. Climbers see wear issues from flexial damage, stress, and wear from comtamination, and UV. I've been doing a lot of sailing recently. You haven't seen uv till you've worked with sails and bimmanies.

Start by reading the new Parachute Riggers Handbook. Do a seach on the riggers forum on dropzone. You can down load it from the FAA. It's one of the best modern collections of information. Bad news is that it's one guys oppenion. You can also get copy of the parachute manual one and two. They're actually really good but they are dated.

If you do a search on the riggers forum you'll find that this is a subject of debate with people villently defending their positions. The life span issue is a huge debate right now with a lot of legal undercurret. you'll also find threads on uv dammage to diffrent fabrics, and diffrent colors. get a rigger to teach you how to do a pull test on fabric and do a number of them on diffrent parts of the canopy. Read about PD's perosity test. I'm not sure what they charge. It's normally done on their reserves so they have a vested interest but they might help you out just from cureosity. Thread is something often over looked and it can be the failure point with uv. The best pollester thread on the market is less then half the life of sunbrella.

If I recall the FAA has test standards for both fabric aircract and Balloons. Talk to a good A+P but I think it involves dropping a steel ball from a certin hight. They do interesting things with aluminum bases coatings an paints. One of the big problems they face is these coatings drying out. This is a probblem with all plastics and is one of the ways they detererate over time. I seem to recall that there are some treatments that basically revitalize and soften it again but I think it's mostly for the coating not the fabic it self. I don't know how much it actually helps the base fiber. The Balloon standard are very simular to our own, that's where we stole it. They are playing with new fabrics and coating all the time with beter uv resistence. Paragliders are also on the cutting edge of this issue.

Most of the dammage that climbers see is from abrasion but they also get a lot of contamination. Dust and dirt get into the fibers and cut and grind. It's worse then jumping at Eloy. Flexial dammage is harder to judge. There are some interesting scales and industry standards on diffrent fibers as to their wear over time. It's judged with specter on one end and kevlar on the other. Every thing else pretty much falls in between. Lookup some of the standards used in the climbing industry. You'll find it interesting reading see if you can find some of the studies done over the years on failure modes.

I've been doing a lot of sailing recently. Oh boy new things to learn about! I can now finger trap double braided line! It's a whole new world of new fabrics and new threads. Some of the forces are amazing. The UV they deal with is way beyond our worst night mares. Even polester thread wont take it. There are some new fibers that are amazing but they are a bitch to sew with. I'd love to see a better braid in them.

So basically there are some places to go and start learning. Lot's of cool things out there.

Lee

 

I'm sorry. I have to give you shit about that. That shit might cut it at the drop zone but not here. What he needs to do is to BECOME a knowlageabe rigger. It might be ok for a little student to abdicate the right to make decisions about his life and safety at the dz but that doesn't cut it on the cliff edge.

Bad, bad attitude to spread. Sorry guy but you were sounding like a little dropzone.com bitch there.

Lee

Just thought of adding some visuals I came across about 'old' and 'surge' :-)
(He also attributed the brake settings to the surge I think.)

Old Mojo, jumper many times over 7 years....the author said :-)

The video : http://www.johnnyutah.com/...s/toggletraining.mov

edit: making clicky

I agree with you 100%

but one does not become competent overnight - and there's no better way to learn than from people who already know. Unless of course you want to re-invent the wheel.

my advice was for the particular situation - an answer the OP can have today/tomorrow as opposed to after months of learning the trade.

???

Please explain?

Its my understanding that when an old canopy that has lots of jumps has lost its 'coating/chemical' that it pressurizes much quicker and therefore begins to fly a lot quicker. True you can adjust your brakes, but how many times can you adjust your brakes before it starts to stall on opening.

My point I guess was if its a canopy that has no history available, and does not perform the way it should, he ought to think about a new(er) one.

While Im typing this Im thinking I could be recalling some skydiving information. If Im wrong Im wrong.

0-3cfm (f111) does not have a coating which most base canopies are entirely made of. Zp does have a coating, but even if it wore off it would gain more porosity and take longer to open.

If the coating wore off, how would it take lo....

Oh I see, nevermind, Im backwards.

Here's a general description.

F-111 is calendered. Meaning it's run through heated rollers to smash the fabric flat. When it's new, less air gets through. As the material is handled, the flattened out threads become more round and allow more air through.

ZP coating is practically ZP throughout the life of the material. Even when it feels worn out after 3000 jumps, not much air can get through it.