Re: suspension
Posted: 2013/07/17 23:05:36 UTC
http://www.hanggliding.org/viewtopic.php?t=29526
Carabiner
- The bottom end is no way safe for sailplanes.
- It's no way in hell safe for hang gliders.
- We violate the crap out of the bottom end all the time and crash a lot of gliders as a consequence.
- You can get killed just as dead by a weak link blow as you can by a carabiner failure and the likelihood is a lot higher.
- We just killed somebody five and a half months ago because he was near or below the bottom end.
- So how come nobody seems very interested in this range?
- It's stupid.
- Not that it can't happen but nobody's ever been killed because of a hang glider carabiner failure.
- A lot of people have been seriously fucked up and killed or drowned because they couldn't free themselves from gliders when they needed to.
- It's enough of a bitch to free yourself from a glider with just one carabiner.
If you wanna fix stuff there's plenty you can do instead of fixing something that ain't broke by making the system more dangerous.
Carabiner
There is no problem. The carabiner bottoms out at fairly light loading. If you want repeated flexing use it for climbing.Dontsink - 2013/07/16 21:30:01 UTC
Spain
In flying sports it seems the problem are not the shock loads (much less than in climbing) but the repeated flexing within the limits of gate play.
We have a legal / FAA defined range for weak links.Dan Harding - 2013/07/17 16:36:02 UTC
ANSI/ASSE Z359.1-1992 (R1999)
Safety Requirements for Personal Fall Arrest Systems, Subsystems and Components- (Historical Document)
Establishes requirements for the performance, design, marking, qualification, instruction, training, inspection, use, maintenance, and removal from service of connectors, full body harnesses, lanyards, energy absorbers, anchorage connectors, fall arresters, vertical lifelines, and self-retracting lanyards comprising personal fall arrest systems for users within the capacity range of 130 to 310 pounds (59 to 140 kg).
I would not use anything that does not meet or exceed this rating.
- The bottom end is no way safe for sailplanes.
- It's no way in hell safe for hang gliders.
- We violate the crap out of the bottom end all the time and crash a lot of gliders as a consequence.
- You can get killed just as dead by a weak link blow as you can by a carabiner failure and the likelihood is a lot higher.
- We just killed somebody five and a half months ago because he was near or below the bottom end.
- So how come nobody seems very interested in this range?
Yeah.AndRand - 2013/07/17 17:21:54 UTC
Poland
Are there any cons of using double biners - one spare, i.e. bigger to hang loose in case of failure of main?
- It's stupid.
- Not that it can't happen but nobody's ever been killed because of a hang glider carabiner failure.
- A lot of people have been seriously fucked up and killed or drowned because they couldn't free themselves from gliders when they needed to.
- It's enough of a bitch to free yourself from a glider with just one carabiner.
Wouldn't help - and you're mashing one carabiner up against another.Excessive wear would be an issue?
If you wanna fix stuff there's plenty you can do instead of fixing something that ain't broke by making the system more dangerous.
Goddam right.Dontsink - 2013/07/17 20:30:49 UTC
Not defending aluminum biners but first failure was at 7300 lbs, which is about 25 G's...
Do not think my glider, harness, or body can take that anyway.
Jason Boehm - 2013/07/17 20:35:28 UTC
http://www.geir.com/mythbuster.html
Myth:Source:Carabiners are susceptible to hair-line fractures if they are dropped. These fractures cannot be seen by the naked eye, but can drastically weaken a carabiner. So NEVER DROP YOUR CARABINER. If you do, it is best to discard it immediately and replace it with a new one.
http://www.cbcnsw.org.au/docs/AbseilGuidelines.pdf
Reality:
This is not true of modern carabiners.
First, the "grain" of the aluminum runs parallel to the stock, not perpendicular, so undetectable hairline fractures spontaneously causing carabiner failure just isn't true. Steve Nagode, a quality assurance engineer with REI, conducted an experiment in which carabiners were dropped six times from a distance of 10 meters onto a concrete floor. The breaking strength of the carabiners was then determined with a 50-kN load cell. The results: no reduction in strength was observed when comparing the dropped carabiners with carabiners that had not been dropped.
Black Diamond's website says this:It's best to inspect dropped gear for dings and significant trauma. If only light scratching is visible and gate action is still good, there is a good chance it is fit for usage.