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#1
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Parachute 20 year limit
I have a security chute that is older than twenty years of
experience. Are you guys finding that the repackers are refusing to recertify past twenty years? Seems the manufacturers have put out service bulletins recomending twenty year service limits. I am interested in getting this chute repacked if possible. Please let me know of anyone that might inspect this chute. Preferably near Atlanta, GA. |
#2
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Parachute 20 year limit
On Dec 3, 8:34*am, wrote:
I have a security chute that is older than twenty years of experience. *Are you guys finding that the repackers are refusing to recertify past twenty years? *Seems the manufacturers have put out service bulletins recomending twenty year service limits. *I am interested in getting this chute repacked if possible. *Please let me know of anyone that might inspect this chute. *Preferably near Atlanta, GA. The thing is, while it is not an FAA mandate, (the 20yr thing...) the individual packer who certifies it as airworthy has their butt almost as much on the line as yours is while wearing it, and studies have shown that 20 yrs of normal use/exposure is approaching the safe working life limits of the materials. I've heard of 20 yr old containers that look perfect, with perfect looking canopies that you can easily jab a finger through. IMO parachutes are just jot a good arena to skimp in... -Paul |
#3
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Parachute 20 year limit
sisu1a wrote:
The thing is, while it is not an FAA mandate, (the 20yr thing...) the individual packer who certifies it as airworthy has their butt almost as much on the line as yours is while wearing it, and studies have shown that 20 yrs of normal use/exposure is approaching the safe working life limits of the materials. That's not what Strong parachute says, or my rigger, so I'd like to see these studies for myself. Do you have a link to them? Mostly, I'm puzzled by the idea that an emergency parachute has a "working life limit" because it doesn't work: it just sits there. I would think it's only a matter of how long the materials last, and nylon and metal will last indefinitely in a cool, dry place. -- Eric Greenwell - Washington State, USA * Change "netto" to "net" to email me directly * Updated! "Transponders in Sailplanes" http://tinyurl.com/y739x4 * New Jan '08 - sections on Mode S, TPAS, ADS-B, Flarm, more * "A Guide to Self-launching Sailplane Operation" at www.motorglider.org |
#4
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Parachute 20 year limit
sisu1a wrote:
studies have shown that 20 yrs of normal use/exposure is approaching the safe working life limits of the materials. That's not what Strong parachute says, or my rigger, so I'd like to see these studies for myself. Do you have a link to them? Eric Greenwell - Washington State, USA I do not, I was passing along hearsay from a trusted source, and after searching the best I could find was this article on the subject form 1958, http://tinyurl.com/6b5bca (.pdf file...) which admittedly does not really support my point much being as old as it is. After talking with a prominent rigger today while I was picking up my National, I asked him about it to find the answer so I could provide such data. He could not point me to any sources either, although he of course agrees with the 20 yr thing. His suggestion was to ask some higher ups at Parachute Industry Association, which I have done, and I will share anything I turn up from that avenue. Also, here is a link to the PIA rigger's newsgroup, where I'm sure you could get more useful info there if you are motivated enough on the subject to post/search the http://www.websitetoolbox.com/mb/rig...ool/mb/riggers Mostly, I'm puzzled by the idea that an emergency parachute has a "working life limit" because it doesn't work: it just sits there. I would think it's only a matter of how long the materials last, and nylon and metal will last indefinitely in a cool, dry place. Poor choice of wording on my part I suppose. I didn't mean time spent 'working' when I posted that, but rather the length of time it is still fit to work if it needs to. According to the same rigger, the older nylons (like what would have been used in the 1958 study linked above...) actually held up longer than the newer materials, but was lower performing in actual use. Much like today's high performance optics, today's high performance parachute materials have special coatings that affect the physical properties and such, but on chutes they supposedly degrade and rub off over time, even under the best of conditions. 20 yrs is even thought to be optimistic to some for this reason... -Paul |
#5
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Parachute 20 year limit
What is this about round vs ram/square? I thought it was generally
accepted that ram/square give more control and lower descent rates, but are less suitable for glider emergency chutes because they work reliably only if you are the right way up etc. when you pull them. Whereas it used to be said that round ones may give no or less control and a higher descent rate (for a given area), and you may get broken ankles, but they are better life savers because they deploy more quickly and reliably when used by untrained glider pilots in emergency when you may deploy them in far from the best attitude. True, false, or what? Chris N. |
#6
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Parachute 20 year limit
False. I believe squares are (slightly)more reliable. Only problem with
squares is that an untrained jumper can hurt/kill themselves landing one. Square parachutes accelerate when turning(think glider without pitch control) hence turning low to the ground and impacting while the parachute is descending is the issue. I believe there are two companies selling square pilot rigs: Paraphenalia and Rigging Innovations. Rigging Innovations has two versions one is a standard square reserve for experienced jumpers or folks willing to get training and the other has a detuned square that still gets better descent rates than rounds. I don't work for either company but being an exskydiver I use(well wear) a square parachute. They are more expensive by probably $700-$1,200. take good care of them and they should last more than 20 years... At 12:20 05 December 2008, wrote: What is this about round vs ram/square? I thought it was generally accepted that ram/square give more control and lower descent rates, but are less suitable for glider emergency chutes because they work reliably only if you are the right way up etc. when you pull them. Whereas it used to be said that round ones may give no or less control and a higher descent rate (for a given area), and you may get broken ankles, but they are better life savers because they deploy more quickly and reliably when used by untrained glider pilots in emergency when you may deploy them in far from the best attitude. True, false, or what? Chris N. |
#7
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Parachute 20 year limit
On Fri, 05 Dec 2008 04:20:16 -0800, cnich15000 wrote:
What is this about round vs ram/square? I thought it was generally accepted that ram/square give more control and lower descent rates, but are less suitable for glider emergency chutes because they work reliably only if you are the right way up etc. when you pull them. My chute, which was put together by John Rix (Southern Parachutes) is now old enough that he's repacking it on a year-by-year basis. He's willing to replace the canopy when the time comes if he can find one, but says round canopies are becoming very hard to find. So, I asked him about replacements. He suggested the Rigging Innovations Aviator model. It has a square, 7 bay canopy that can't be stalled, and so needs no more training than a round parachute. They're not cheap ($US 2300 on the web site, compared with £1250 for a Strong from AFE). -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#8
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Parachute 20 year limit
true....almost any parachute manufacturer will tell you the same...Round
parachutes are tested in order to pass TSO standards and have to be able to successfully deploy when: packed wrong, deploy even when pilot is in any position, when the parachute is soaked, dirty, even damaged and more...Square sport parachutes must also be "flown" and even student squares which are tamed down so they cannot fully stall or high speed take some training and knowledge as well as an astute pilot who is fully aware of what is happening, not always the case when the pilot is bailing out of a mid air or disabled aircraft...knowing full well that many glider pilots may not have even read the operators manuals for their emergency parachutes and have little of no knowledge of how to use one if the occasion shows itself makes for a far better choice of a round emergency parachute than a square for 90%+ of the potential users... yes....you might hit the ground with a bit of an aaaarrrrrgggghhh with an emergency parachute..but you'll have enough adrenalin pumping you won't even feel it....if you happen to land wrong as you may well ...you could even bust an ankle though you probably won't unless osteoporosis has already set in...but you'll likely live to write the story and fly another day... tim Please visit the Wings & Wheels website at www.wingsandwheels.com wrote in message ... What is this about round vs ram/square? I thought it was generally accepted that ram/square give more control and lower descent rates, but are less suitable for glider emergency chutes because they work reliably only if you are the right way up etc. when you pull them. Whereas it used to be said that round ones may give no or less control and a higher descent rate (for a given area), and you may get broken ankles, but they are better life savers because they deploy more quickly and reliably when used by untrained glider pilots in emergency when you may deploy them in far from the best attitude. True, false, or what? Chris N. |
#9
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Parachute 20 year limit
Cris and all
Some stories on chutes. I'm retired AAF/USAF and punched from a jet over Greenland in a snow storm in the middle of winter and walked. I'm a member of the Catapiller Club (It's still in existance so anyone who bails out can join and get the pin). Military chutes at that time were 24 foot round. Prior to and during WWII they had two diameters. 28 foot if you weighed over 190lbs and 24 foot for us skinny guys. Idea was to reduce landing accidents cause by descent rate. History showed that the landing injuries didn't go up very far with heavy pilots using the 24 foot so system was changed and only 24 foot became standard. It was cheaper to only have one style and the 24 foot fit better in the small fighter cockpits. After the War and due to the possibility of high speed bail out, they started enclosing the canopy in a 'bag'. When the chute was deployed the canopy stayed in the bag until the shroud lines had fully extended at which time the pilot chute pulled the bag off the canopy and it deployed. This reduced the whip lash problems with canopy deploying and the pilot falling away from canopy until the shroud lines were full out (snap, crackle and pop). There were two shroud lines on right and left rear that were flagged in red. These shrouds could be cut after canopy was deployed and the canopy then distorted and had some forward motion. By pulling on the right or left shrouds you could turn the canopy and this gave you some rudimentary steering ability. Prior to landing you rotated the canopy so that you would touch down facing forward downwind. Upon touch down you executed a parachute landing roll like the Para Troopers use. You then dumped the canopy to prevent dragging in the wind. My advice is to use the MOST RELIABLE chute under ALL conditions (round) and get some rudimentary training in its use. Merry Xmas and good and safe flying. (No chutes please ) Big John ************************************************** ****************************** On Fri, 5 Dec 2008 04:20:16 -0800 (PST), wrote: What is this about round vs ram/square? I thought it was generally accepted that ram/square give more control and lower descent rates, but are less suitable for glider emergency chutes because they work reliably only if you are the right way up etc. when you pull them. Whereas it used to be said that round ones may give no or less control and a higher descent rate (for a given area), and you may get broken ankles, but they are better life savers because they deploy more quickly and reliably when used by untrained glider pilots in emergency when you may deploy them in far from the best attitude. True, false, or what? Chris N. |
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