speed link

[jimrooney]

Ah, I see some of the problem here....
Lack of objection is not agreement. A misconception you seem to make often, thus many of my objections.

Notice my lack of objections here. This does not mean that I agree with you. Tomato tomato on this one.

I even ask for clarity and get bile in response.

I don't have a whole lot of peers with respect to some of my little niche issues.

Oh, I'm not so sure about that. (on many levels)
There are extremely competent people lurking on the Oz Forum. They poke their heads up when technical issues arrise.

You just use the excuse (as expected) of there being arrogant loudmouths there to avoid critisism when it's much easier to sit here in your little pond and rant and rave. (reminds me of someone I know)

I do "go global"... far more than yourself.
My positions differ greatly from yours, but I do subject myself to peer review. I put up with those arrogant loudmouths wile seeking the wisdom of the quiet experts.

It's not my head that's in the sand.

[Tad Eareckson]

(Oops. That "I'll" was supposed to be an "I'm".)

No, Brian, I'm saying that in that scenario go ahead and use the carabiner - especially if it's cranking enough to make things dangerous. These aren't the circumstances in which we're gonna have hook-in problems.

However, making the speed link connection on the ramp would only cost about twelve additional seconds anyway.

I can't see any point to climbing into the harness on the ramp. There's an easier way to ensure that you're connected than that. I wouldn't even want to crew for that procedure unless the winds were reasonable and the line was extremely short.

No, foot launch towing isn't a big issue around here - but we know how terrible the consequences of being a little too human in that environment can be and that that was not just an isolated freak incident, rare though it might be.

I just started talking to Peter Birren on the issue. I'm thinking that a well proportioned Hewett bridle system may just about eliminate the possibility of anything like this happening but we know for sure that the next time we get a similar report the sequence of events will not have included a glider getting loaded onto a dolly.

[Flying Lobster]

...

My friend Bill has lost both his legs from forgetting to hook in.

The guy who attempted the foot-launch tow? Very sorry to hear that, major bummer.

marc

[Tad Eareckson]

\
/
In all likelihood, maybe ten years from now, after the recent incident has faded from everyone's memory and procedures like running launch checklists are so familiar they've become a part of the background, someone will become distracted and fail to hook-in once again.
/
\

So here we are, four days shy of the Aluminum Anniversary of the catastrophe which prompted Mark's ten year estimate which - any way you want to measure things - proved way optimistic. We kept doing things the same and got even worse results. Big surprise.

Having perused a few other recent threads I note that several individuals appear to be irritated at all my ranting, raving, griping, blogging to this "captive" (read totally voluntary) audience (which is alternately way too big and way too small) and would rather have available only happy stories about people boating around on the ridge all afternoon.

(Clever comment, Chris. Did you come up with that one all by yourself or did you rip it off from Yogi Berra?)

Well, actually, I'd rather read nothing but happy fluff myself but every now and then I see a post about some weekend outing or big flying adventure gone sour when one of the guys ended up a foot and half shorter and I feel that you've got to have a lot more of the former to justify the latter.

A few years ago I griped and bothered people that we needed redundant weak links and Steve announced that he had developed a dead man switch release. Those technologies were ignored and one of the local crowd consequently required medical attention to the tune of - I'm guessing - some very noticeable fraction of a million bucks. (Now everyone's flying with redundant weak links and there are three of us who are completely assured of being able to end tows anytime we want.)

I'm also guessing that everything I've ever posted to this forum costs some fraction of a nickel's (or penny's) worth of storage.

Let's also weigh that figure against the following entirely fanciful and highly unlikely scenario...

(harp music)

Eighteenth Annual McConnellsburg Hang Gliding Festival

2010/09/19

Day 2 - Sunday morning

At 07:30 one of the few participants who didn't overdo it last night notices that it's coming straight in at seven. His glider is still set up 'cause the catabatic flow interrupted his plans for a sunset sled.

Unfortunately, it's about time to settle up with the statistics we've agreed upon and glider and pilot depart the north ramp along separate paths. Both leave Tuscarora Summit in bags - the former to fly again (after a few battens are straightened) piloted by the latter's best friend to honor his memory.

This one - from 2005/10/05 - is Brian's:

\
/
We need to be more vigilant, more insistent....and yet within 10 years this will happen again. We can and should blame the HG culture as a whole...
/
\

The family, however, and its lawyers decide just to blame CHGA and the volunteer fly-in director (let's say - what - about ten million dollars?).

And there ain't no Nineteenth Annual McConnellsburg Hang Gliding Festival 'cause now there's a MacChateau where the ramps used to be and a NO TRESPASSING sign at the gate.


But nuthin' like that could possibly happen, right?

2005/10/13

Deanna Priday

\
/
...

I know that the hang gliding community is taking this to heart and some good will come out of Bill's death:

* change the design of whatever you have to to make it APPARENT...you are not hooked in. I think the Priday Straps or something would be wonderful...
...
*write articles on how to make it safer
*Implement what ever you have to so that : NOT ONE MORE PERSON dies because he/she wasn't hooked in.

...
/
\

The problem with the Priday Straps - as they were envisioned earlier in that thread - is that even if the suspension is colored garishly enough to cause midairs in vulture kettles it's still totally invisible to the pilot at show time. Coulda helped with respect to the crew but did anybody beyond Shawn get around to implementation?

Otherwise...

Yeah, I changed the design - it's still behind me so it ain't exactly apparent, but I'm a whole helluva lot more likely to be aware of its status.

To the annoyance of several individuals who, I don't believe, have ever themselves had anything new to contribute to glider safety technology, I have publicized the modification and attained a consensus that it will work.

And the design has been implemented - unfortunately so far and to my knowledge - only on one of the gliders which stays in an environment where the main issue is irrelevant.

\
/
If you use a CHGPA resource, then you should have the common decency of paying your dues.
/
\

How much of a resource this forum represents depends upon what's on it. I think we can all agree that it would have been in no one's best interest to rescind Greg DeWolf's right to post. If you silence Bacil folk are gonna have a lot harder time planning their ridge excursions two weeks in advance. There are a few individuals who bring a lot more to this resource than they take away from it.

\
/
We need pilots to support the club not just with dues money, but with ideas and time and effort.
/
\

So maybe (Matthew) you oughta be doing the arithmetic this way... I've given y'all tens of thousands of dollars worth of volunteer statistical and accident analysis, innovation, engineering work, documentation, and presentation which anyone is free to adapt or ignore and there haven't been a whole lotta people clicking support into my PayPal account or donating materials, components, or instrumentation. So it could be that the imbalance isn't actually tipping the way or to the degree it's being perceived.

There are a couple of ways the integrity of my work can be verified...

What I'm recommending is that this community start shifting to bolt-on connections in potentially dangerous and appropriate environments (most of them). If it does so I think we can make it to 2018/01/10 with no relevant unpleasantness.

Or we can just wait until after the hypothetical Pulpit Fly-In 18. I'm sure the plaintiff's attorneys, after running a few google searches, will hire a well qualified aeronautical engineer to appear as an expert witness and discuss - in sworn testimony - his professional opinion concerning what we could have been doing and why we weren't.

[Tad Eareckson]

OK, no one hopes more than I do that this post can serve as a wrap-up of this topic.

Half past last month I rekindled a topic on the skysailingtowing forum by reporting the 2007/10/18 catastrophe.

Prior to that discussion I assumed that that had been a freak accident. Now, with six accounts of unhooked tow pilots holding onto and climbing with the glider, it appears that this is actually the default mode. (I know of one incident in which the pilot immediately let go and hit the release.)

I had previously thought that windy slope/cliff launches might not represent too much of a problem. You don't need much/any ground speed to attain sufficient airspeed so when the glider starts floating up too high without lifting you just kiss it goodbye and, if necessary, hit the brakes.

Naw - we're instinctively gonna hold on for the extra second that will make things too late. Count on it. We might be able to train ourselves to react appropriately but I think we're better off using equipment and procedures which eliminate or reduce the possibility of putting to the acid test the effectiveness of that conditioning.

A survivor of an unhooked tow launch very similar to Bill Floyd's (right down to the left turn and 25 foot fall) paid with (only) a broken wrist, is a strong advocate of dolly launching (in Portuguese and English), and concurs with my recommendation of the speed link - both with respect to structural suitability and effectiveness in reducing hook-in failures.

For towing, dollies (or platforms) are (again) bulletproof. I've so far not heard a great reason for not using them.

However, a Hewett (2:1) bridle is probably an acceptable alternative. The (any) lanyard should have minimal slop and be routed over the basetube and anchored at the shoulder, but I've got one report of even a wrist attached line doing the trick. I'm guessing it's impossible to get off the ground if you're not hooked in.

I think the Aussie method has put a real big dent in the statistics - it may be that no fanatical practitioner has ever eaten grass, dust, or rock. But it's not practical and/or safe in all environments and, while being my technique of choice where comfortable, I don't see it as being necessary.

Hang checks are not hook-in checks. The only way to fulfill the USHGA requirement which got you all of your ratings to date was to have performed a hook-in check JUST PRIOR to every launch.

For a platform or dolly launch the hook-in check is automatic. For a foot launch almost everyone can lift the glider or allow it to float up in the breeze to the point of feeling a tug. Anyone else can lower or lean his body to achieve the same confirmation.

I KNOW OF NO INCIDENTS INVOLVING A PILOT WHO HAS MADE THE REQUIREMENT HIS ROUTINE.

Anyone who ever moves a foot forward without first tensioning his suspension - be it Whitwell, the Pulpit, Taylors', Jockeys Ridge, or scooter tow - should be zapped with a cattle prod as soon as safely possible and forced to buy beer for all present.

Bolt-on harness suspensions encourage the Aussie procedure and will otherwise decrease the probability of launching unhooked because the pilot is much more likely to be aware of the status of his system at any given time. The connection is not appropriate for all launching and landing environments but is quite practical for the bulk of the former in which hook-in failure would be catastrophic.

While the numbers for these systems are still low, I KNOW OF NO INCIDENTS INVOLVING A BOLT-ON SYSTEM.

If the pilot arrives at launch without being in the control frame of his glider he's probably safe. In such a case there will be at least two people to whom it will be blindingly obvious that he is not connected and rectifying that situation will automatically be on the front burner.

I KNOW OF NO INCIDENTS INVOLVING A GLIDER MOVED INTO POSITION BY ANOTHER INDIVIDUAL.

So the next time we see a glider shoot back up minus its pilot, who will the owner have been?

The usual suspect.

He'll be using a pod harness with a single suspension element with a six ton locking steel carabiner on the end of it.

He'll do his full hang check - as usual - in the staging area just behind the ramp with John (Doe) holding his nose. This operation won't tell him anything 'cause his clearance won't have changed since the last time and there's nothing he can screw up anyway but - hey, this is the way we do things.

He'll remember that he meant to replace the batteries in his GPS receiver with the freshly recharged ones back at the car. He'll not be thinking, "Damn, now I need to get the screwdriver bit out and go through that drill two more times."

Back at the glider he then switches the receiver on for a check before he hooks back in. While he's waiting for a satellite lock with his foot on the basetube the ramp is hit by a thermal blast that the wire crew of the glider currently in position will not soon forget. A "Holy SHIT!" or two is elicited but everything stays under control on and behind the ramp and fifteen seconds later the launch is effected smoothly in light air.

Our subject then carries his glider up onto the ramp subconsciously remembering that he's done his hang check with John holding his nose. (All on crew are waiting for their pulses to return to normal while watching the previous glider scratching up and thinking about the last couple of setup steps awaiting their own rigs.)

Thirty seconds later and three steps down the ramp he will remember that he didn't reconnect. Two more steps and the crew becomes aware of the oversight.

For one reason or another he won't make that mistake again. And then we can have the usual two hundred page discussion... (And I'll just post a link to back here.)

Along the lines of the Mike Meier "Safety Thing" article which Bacil referenced (oops - Marshall, not Crestline)... If we have enough of a foot launch pilot population to feed the statistics we'll always have hook-in failures. Let's say we've been doing things right and/or lucking out 99.99 percent of the time and that, over a decade, locally, leaves us Bob, Marc, and Bill. If we improve our performance by a factor of ten we only mangle or kill someone once every fifty years. I'm pretty confident that a shift towards the above recommendations will take care of that magnitude and more.

[Matthew]

Hi Tad,

CHGPA is planning on several safety initiatives this year-- some of which costing the club some money. So if you wish to support safety, then try paying your club dues.

Speaking of which, BIG THANKS to all the pilots who have paid their dues-- 63 so far. That's one quarter of the people on the CHGPA forum.

Twenty-five percent. HOORAY!!!

Besides Tad, a few notable exceptions include HG pilots with initials DT (delinquent for 2007 as well) and CM. So please pay your dues. Or you will be getting a visit from Matthew. You don't want a visit from Matthew. I'm known for sarcasm, irony and very bad puns... very, very bad puns!

For details on paying your dues, see -- http://www.chgpa.org/ClubInfo/chgpa.memb_info.html

Matthew

[Batman]

I just got back from the holiday vacation and put my check in the mail. Proverbial "Check is in the mail" story, but Dave will be receiving it any day, thus clearing my name from all Matthew-isms.

CM

[Tad Eareckson]

Back again, sorry.

Finally got around to assembling enough nuts, bolts, washers, and two by fours to slap together a high capacity load tester and get some qualification for the stuff which will be keeping me attached to my glider when the sun starts getting a lot higher than it does now.

I'm using the Wills Wing hardware which has been used on all of their kingpost suspension gliders from back at least as far my HPAT through their current models. My homemade version incorporates light (thousand pound) flat nylon webbing tabs engaging the tangs and a length of 2700 pound one inch tubular polyester webbing as the main element (thought it was nylon at the time of the fabrication but what the hell), extended to make up the three inch difference between the carabiner and speed link. The two flavors of webbing are hand stitched together using nylon floss.

My hydraulic cylinder based weak link tester gets me up to 776 pounds and I used it to find out how much tension is yielded by applying an inch pound to a lubricated 5/16-18 inch long coupling nut with a torque wrench - came up with with an average of 16.7 pounds.

I assembled everything - bushing, spacer, bolt, nut, tangs, webbing, speed link - in a long narrow frame, donned the safety glasses, shooed away the parrot, and cranked up to 150 inch (12.5 foot) pounds - at which point I became worried about stripping the nut and rod threads. Even dumbing down my average to fifteen pounds that's one and an eighth tons - 2250 pounds - nine Gs for my 250 pound hook in weight (which happens to be right at the top of the recommended hook-in weight range).

At that loading the suspension elongates about 60 millimeters from its at rest 610 millimeter lower tang eye to speed link figure and takes on the hardness and edge characteristics of a samurai sword. I didn't hear anything when I plucked it but all the bats in the attic came out of hibernation.

After backing off and going over everything with a magnifying glass there was zero evidence of damage, distortion, deformation, stress.

Wills Wing doesn't seem to include this anymore but check this out from an old manual:

-

The positive limit load of the Raven is 3 G's.

The negative limit load of the Raven is 1.5 G's.

NOTE: Limit loads are defined as the maximum loads to be expected in normal flight operation. THEY DO NOT represent the ultimate loads which the glider is capable of withstanding without failure. The Raven has been tested to more than six G's positive without any permanent deformation of the glider's structure. The Raven has been tested under negative load to the limits prescribed in the HGMA standards, and has been found to exceed the prescribed load limits by a significant margin.

-

Today's gliders are a lot cleaner and fly a lot flatter and faster but I'm guessing they don't handle positive loading any better (and suspect the topless birds are significantly less robust in negative mode).

So gliders are expected to stay well within three Gs (and I don't remember ever having pushed that envelope) but can handle more than six. The suspension I put together - using much lighter webbing than stock - wasn't even breaking a sweat at nine or ten. And this is the component which we absolutely must back up?

The reason we have backup suspension is because we - irrationally - insisted on it. Conversely the reason we don't have flip down hook-in warning flags at our noses - about the same cost, less drag - is 'cause we didn't give a rat's ass. Which has / should have saved more lives?

[Flying Lobster]

check this out Tad

http://www.uptimal.com/Paragliders_%26_ ... es.html#24

marc

[Tad Eareckson]

I tried, but the link seems to be screwy. I'm guessing you're talking about some sort of paraglider harness connector but I keep dead ending at powered paragliders. Any other way you can direct me to the hardware I'm presuming?

Anyway, as long as I'm here and speaking of hardware...

I've long been bothered by the degree of overkill and weight of steel carabiners and have a supporting voice at APCO Aviation. They document that if you properly design and forge the aluminum such that the manufacturing process doesn't weaken it and the tolerances are close enough to preclude a lot of flexing and fatiguing you're gonna stay in good shape.

Unfortunately their carabiners aren't shaped very well for use with hang gliding suspension but the Omega Pacific Oval:

http://www.omegapac.com/opo6.html

and the Black Diamond OvalWire:

http://www.bdel.com/gear/ovalwire.php

don't look like a bad options. The shape is gonna be kinder to one inch webbing than anything else I've been able to find in the carabiner sphere and the ratings - 22 and 23 kN respectively - are pretty respectable for that sort of design. I don't think a locking mechanism has ever been of the slightest use to any of us.

I don't yet have my hands on either but just played around with a pristine 18 kN - 6 open - Black Diamond Oval.

The clearance between the pin and notch in which it is engaged is almost precisely 2 millimeters. This is a lot more slop (which allows more flexing) than would seem to be ideal for us but I guess the idea is that a climber might want to be able to open and close the gate with the carabiner partially loaded.

At 303 pounds the pin starts making contact as the gate is opened and closed, 326 pounds locks the gate closed, and 481 pounds firmly seats the pin. Expressed as percentages of its ratings that's 07.5, 08.1, and 11.9 major and 22.5, 24.2, and 35.7 open.

Black Diamond advertises that they test load all their carabiners to half their ratings before they ship. That's probably a good compromise between ensuring that the hardware will do what it's supposed to and weakening it through stress.

Seattle Manufacturing Corporation has a pretty good page:

http://www.smcgear.net/caresheet.asp?id=1

about taking care of and keeping an eye on aluminum carabiners. To briefly summarize...

Pins vulnerable.

Moisture bad.

Salty moisture (environmental, hands) very very bad.

Keep clean, dry, and warm and spray with WD-40 once in a while.

Don't keep absentmindedly snapping the gate as we all find ourselves doing whenever we have a carabiner in a hand for about two seconds or more.

So in the unlikely event I ever find myself back in a speed link unfriendly and/or inconvenient environment I'm gonna commit yet another act of hang glider heresy and revert to what we were all using before (and what PG folk are using now (be it in pairs) anyway, right?). I'll be very kind to it, check it with a magnifying glass every now and then, and test load it to eight Gs every February when I repack my parachute.

Something to consider if you're still not happy using anything less than a fifty G steel carabiner to connect yourself to a seven G glider... When you're cruising at thirty-five thousand feet in a 737 going three quarters the speed of sound and slam into turbulence halfway between here and the MSP hub you're only good for four Gs.

Babbling on...

I put together a loaner suspension assembly which can be used on any Wills Wing kingpost suspension glider. It's infinitely adjustable and probably a good bit cleaner than the ladder jobs. On each side light flat webbing engages the tang and extends to just below spreader level. In a loop at the bottom end is secured an RF2182 Ronstan Sailmaker's Thimble.

The thimbles protect the webbing from a doubled length of five thousand pound low stretch quarter inch line. Adjustment is effected using a multiple coil Becket (Sheet) Bend. Four one inch lengths of 32-24/64 inch vinyl tubing hold the line in the thimble channels and keep things from getting sloppy when not under tension.

So if you wanna play musical gliders and you're not happy with extensions and/or wraps...

And, as long as the flying weather ain't that great...

I recently did a quick little search to get a feel for how many people are breaking their easily inspected ten thousand pound suspensions and dropping into their backup loops versus those breaking their sub one thousand pound flying wires and dropping onto the ground (i.e., if we really need to back something up...).

Didn't come up with much in the latter category but there was a fatality in Australia in 2001 and a very serious and flying career ending fall in Washington in 1996.

The latter accident involved a Super Sport 143. The integrity of the wires was known to have been questionable by the pilot and her glider associates. Nowhere in the dissection discussions of three individuals is there a specific reference to the most important element of the preflight which has been included in every Wills Wing manual from at least nine years prior through to the present - Step on the wire and push up on the leading edge 50-75 pounds.

[RedBaron]

I don't think a locking mechanism has ever been of the slightest use to any of us.

I know. What's up with that? Coastal flyers are even advised against locking their 'biners.

I'm gonna commit yet another act of hang glider heresy

LOL

Something to consider if you're still not happy using anything less than a fifty G steel carabiner to connect yourself to a seven G glider

LMAO

Off to REI tomorrow for a 7G aluminum biner that can't be locked, enough of this hocus pocus. In the meantime, I saw that for the Matrix harness you can get as an option a riser that goes straight to the dingle dangle. So I figure the harness webbing ends at the bolt that normally connects the hang loop to the dingle dangle. Would that be the type of connection you are promoting, Tad? This solution looks a lot cleaner than the standard suspension-carabiner-hang loop connection, thus my sudden interest. Also, the KAVU guy on the front cover and page 5 of the January issue of the USHPA magazine seems to be connected to his T2 via this method. Please note that a backup connection seems to be lacking, he's totally en vogue.

[XCanytime]

Prone to metal fatigue and cracking. Use of an aluminum carabiner is highly discouraged by those in the know. Bacil

[Flying Lobster]

Prone to metal fatigue and cracking. Use of an aluminum carabiner is highly discouraged by those in the know. Bacil

Exactly right. In addition, load bearing properties are highly variable depending upon shape of biner and load area (ovals are not as strong as D's or modified D's)--and unintentional gate release can happen rather easily on non-locking biners. Their use should be banned from any flight park or mountain site unless doubled up--I mean BACKED up.

And it's off to the races...

Bolt-on harnesses are really quite simple--the Matrix Race (and Tenax too, I believe) has an integral back-up sewn into the main riser which independently loops around the keel and is separate from the strap which attaches to the rocker with the bolt. The principal drawback to this arrangement is that it makes the harness difficult to use with other gliders since the riser length is generally made to fit a particular race ship. It does virtually eliminate the possibility of launching unhooked--but I was working the Flytec meet one year and I caught a world-class comp pilot preparing to tow who had not finished putting the nut on the end of the bolt through the rocker arm and it still supported his weight while hanging in it--it was an extra-skinny riser without an over-the-keel back-up, as I recall.

marc

[Tad Eareckson]

OK, I'm going to retreat a little bit on aluminum carabiners 'cause something didn't sink in until after I posted.

With my 250 pound hook-in weight on the carabiner I tested I don't bottom out until 1.92 Gs (which normally requires a coordinated turn near the limitations of the placard) - which, of course, means that from zero to that figure the thing is flexing to range over the two millimeter gap.

However, it appears that all climbing carabiners are similarly designed and I don't believe that all those manufacturers use idiots as engineers. I think that what they're doing is better distributing the load between the stronger spine and weaker gate and paying for the difference with flex. With the 18 kN Black Diamond Oval the spine is always taking more - up to 481 pounds - of the load. At the rating limit the spine and gate are feeling tensions of 2264 and 1783 pounds respectively.

So we're dealing with some aluminum that flexes under load. Well, the glider itself is aluminum that flexes under load. The carabiner and the kite are both designed to keep the people attached to them from falling thousands of feet and the former is built to withstand better than twice the shock of the latter's capacity.

Yeah, Ds tend to have stronger ratings than ovals. But they have a more adverse effect on the webbing. The load distribution is worse and the wear factor is greater. And we're not concerned with the ratings - they're all overkill. What we're concerned with is durability.

I believe in the first decade and a half or so aluminum carabiners were used pretty much exclusively and none of them ever failed in flight. Eventually we had one fail in the shop and over the carpet at about one G so we can count that as a fatality for argument's sake.

I don't know but I'll betcha a six pack that words like California, beach, salt, moisture, neglect figured into the history of that piece of hardware. And some of that stuff can turn your leading edges into garbage from the inside out as well.

So what other critical items that we're still using today failed during that period?

I'm not advocating a switch back to aluminum - the steel is totally bulletproof. I'm just saying that with a bit of care it can be done and that'll be my choice - especially since I can now verify the integrity whenever I want. Also, if Wills Wing or somebody did for hang gliding carabiners what APCO did for those for paragliding we could shave a good chunk of weight off of our systems without the cost of any sleep.

Janni,

I'm in favor of any suspension system and/or elements that make it harder to screw up and easier for one to be aware of his status without sacrificing any performance or much convenience. Fortunately most of the best looking solutions are win-win(-win).


Marc,

With respect to the nonlocking issue... This ain't climbing. No carabiner (going out on a limb) has ever opened after being snapped to the glider suspension. What's the nightmare scenario?

And like Janni said, if you're near water... And we sure didn't want lockers jamming with sand while flying in higher winds at Jockeys Ridge.

And why is it less acceptable to fly at a flight park or mountain site with a certain piece of equipment than anywhere else? If you can get a hundred and fifty feet over anything more substantial than a down pillow reprocessing center (and that includes water) you're gonna have a bad day if you lose your glider. And I'd just as soon miss the experience of going off the high board into loose sand for that matter.

Definitions quibble... Doubled up is not backed up. A backup is a standby system not subjected to stress until the main fails.

Disappointing to hear about the bolt-on incident. Yeah, you can't screw up with a carabiner used in conjunction with a dolly or platform. As long as there's a way to miss something and kill oneself we humans will find it.

My best shot for the moment -

Although, as JD pointed out, it is theoretically possible to similarly botch the job with the speed link, I don't think it will happen. Once the gate assembly is snapped on - right side up - you're gonna live. Three seconds, no tools.

Leave the suspension - from the spreader lever to the harness - as a semipermanent part of the glider. Stow it inside the double surface when the glider is tied down. Connect to the suspension using a speed link at (or in) the back of the harness. Back up - if necessary - and anchor the parachute there too (I'm guessing a lot of bridles are getting terminated in that vicinity nowadays anyway).

If you anticipate playing musical gliders have a couple of different length suspensions on standby.

[Tad Eareckson]

Omega Pacific makes a carabiner they label as a Tactical Doval Wiregate which gets advertised as "designed to open under body weight load". I couldn't find that claim applied to any other models but that capability may be in large part what's behind a lot of pin to notch slop.

I just subjected a dozen different flavors of aluminum carabiner to a 220 pound load and found the gates of all to be operable - ten freely and two with a bit of resistance.

So maybe we've got a feature we don't need or want built in that permits flexing and fatiguing. Or maybe we do want it 'cause, in the course of a normal flight, that slop usually means that the most vulnerable features of the carabiner are never even loaded - we might as well be flying with the gate missing (as long as we don't go negative) - and fatiguing really isn't an issue.

Along that line... Just about all of these aluminum carabiners have gate open ratings of 7 kN or better. That means that even minus the gate they're likely to survive Gs to around the point at which the glider crumples.

From Wills Wing's TB940802 - 1994/08/17 - another example of the sort of thing that actually fails when the Gs go up (and, presumedly, the preflight is truncated) versus the stuff we worry about and ban from flight parks and mountain sites...

-

Recently an HP AT pilot failed a bottom side wire during an aerobatic pull up. The glider was 18 months old, and had 300 hours on it. There was no visible damage to the cable.

-

[jimrooney]

I believe in the first decade and a half or so aluminum carabiners were used pretty much exclusively and none of them ever failed in flight.

Yeah, cuz he discovered it in his hang check...
http://www.hpac.ca/pub/?pid=157
(took about 2 seconds to find on google btw... ignorance is truly bliss I guess)

Talk about pushing an agenda.
No one's ever discovered that their steel caribiner (of any strength) is broken on launch. The same can not be said of aluminum.

There is absolutely no advantage to an aluminum biner. None. (except that it gives YOU something to argue about).

Go troll somewhere else.
you're boring

[Tad Eareckson]

And if you had bothered to read the material upon which you're commenting you could have saved yourself the two seconds (but what's new...).

Thanks for the link but there's nothing in there that hasn't been discussed already. And, although I have a lot of respect for the authors, there are a couple of points with which I take issue.

max pounds:

T2 154
0285 - recommended hook-in weight
0855 - 3 Gs - loading - anticipated
1995 - 7 Gs - loading - cheat

Black Diamond OvalWire aluminum carabiner
5170 - 275 pound climber - 19 Gs

So...

Are all these climbers and the manufacturers who supply their aluminum carabiners all total freakin' morons? (Feel free to chime in here, Marc.) If they can care for and preflight their critical safety equipment and survive with it so can we. And they're capable of delivering shock loads far in excess of anything that's possible for us.

In zillions of hours of flying with aluminum carabiners we have precisely ONE documented technical fatality involving an aluminum carabiner. And had anybody actually preflighted - i.e., given more than a cursory glance to - this carabiner at any time in the course of its ten year (?) service life. I really doubt that one moment it looked just fine and the next it was on the floor in pieces.

I found four references to side wire failures - presumedly all 3/32 inch - 920 pound minimum breaking strength. Results -

2 - unknown
1 - partially fatal
1 - totally fatal

So are we beefing up to eighth inch to bring us to 1760? Hell no. We're dumbing down to two millimeter - 496. Why? To make the glider go faster. Not that there's anything wrong with that. But let's get a grip on the validity of our priorities.

So to summarize, rephrase, and round off...

If one probably abused aluminum carabiner fails (on the ground) in the entire history of hang gliding we scrap all of its kind for something two and a half times as strong and five times as heavy. But if gawd knows how many side wires pop in flight we don't go to something twice as strong. If anything we cut the strength in half.

Quoting from the article...

-

We do not know of any failures of high quality alloy steel Carabiners, but we suggest that you replace even a steel carabiner after 3 to 5 years of regular service.

-

Oh yeah? My steel carabiner is normally operating at well under four percent of it's rating. What percentage of its rating is my port inboard leading edge section normally taking? How much does it flex and fatigue? How come you're not recommending that I replace it every three to five years?

Poll time - Is there anyone within earshot who actually adheres to that recommendation? And (Part B), if, so can I have your discards?

Naw, there's no huge advantage to using a five thousand pound aluminum - versus twelve thousand pound steel - carabiner. But it knocks close to half a pound of junk off our systems and the glider manufacturers go to great lengths and expense to trim such figures from their birds. And after consulting with some climbing geeks at HTO and EMS I'm not seeing any more reason to pack the heavy stuff.

I'm sure you find this stuff boring. When one has memorized everything worth knowing many years ago everything's boring. So how 'bout doing us both a favor and not click on it.

[jimrooney]

I love the ASSumption that I didn't read your drivel. Next will be the one that I didn't understand your drivel. No, what I'm saying is that it IS drivel.

To summarize and round off...
;)
1) You want to use aluminum caribiners because steel ones are rated far higher than even the glider.
2) You also push the meaningless weight argument.

1) It's not about breaking strength.
You fail to accept this and keep pushing strength.
It's about durability.

2) Weight in the center of the glider doesn't matter (weight at the tips does). You're using this argument as a red herring.

ONE documented technical fatality involving an aluminum carabiner.
(which you know of... other accidents which you do not mention and other non-accidents caught by preflight)

We do not know of any failures of high quality alloy steel Carabiners
(and none found defective in preflight and no accidents)

And now some apples and oranges...
Race gliders.
Pa-leese!
Comp guys are fanatics.
They get rid of the caribiner all together (bolt on harnesses).
To comp pilots, the DRAG of any caribiner is considered.
Clue for you... comp pilots fly under a very different set of risk/reward criteria than a "normal" pilot.
Don't be spewing "hey... but comp guys..." crap.
Totally different set of rules there.

"don't click on it"
This is not a moderated group.
Unmoderated groups are "moderated" by public opinion. (which doesn't work, but it's what we've got)
When someone starts up with the crazy stuff, someone else tells him he's crazy. You often prop up lack of objection as agreement (I seem to recall pointing that out on occassion)... so I'm helping you understand... this IS an objection and you ARE crazy.
I'm not going to refrain from dissenting simply to make your life easier.

This ain't yer blog
Jim

[dbodner]

Not sure why I'm wading in, but I'm drinking a beer. So here it goes...

If I'm emotionally uncomfortable with relying on a single carabiner, do you think it's reasonable to rely on two aluminum carabiners, a primary and a backup? I guess Tad should have no problem, so what do the non-Tad-ers think? Accepting Jim's argument that it's a durability--as opposed to strength--issue, I'd have to be one unlucky (or clueless) SOB to have two 'biner failures during one flight.

Also, I'm trying to picture in my mind the incident in which a non-locking carabiner causes a problem.

Dave (still flying with a single, locking, steel carabiner)

[RedBaron]

Tad, besides all structural considerations, how come you find one FTHI fatality unacceptable and that from a broken aluminum 'biner few enough to promote these now?
BTW, I like how you succeed at pushing buttons. I think it's awesome you found something you're really good at.

[Flying Lobster]

There have been many known failures of aluminum carabiners in the history of climbing--the issue isn't the ultimate shear or tensile strength but what happens to the biner when banged around and the near impossibility of detecting internal fracturing. beyond this, the load bearing ability drops significantly when there is a torquing or side loading not directly along the main axis.

There are also known instances of climbers becoming detached from unlocking biners easily. this can happen with a simple line over the gate forming a loop which inadvertently opens it. Can this happen in hang gliding? Most of the time--most likely not (like those odds?). Is it possible to have a loop of material rest against the gate forcing it to open inadvertently? Just look at a pilot standing on launch with the harness riser and hang strap loose--obviously yes.

The real mystery to me is why this obsessing over reducing 1/100000 point of drag off a nearly 20 year old glider.

marc

[hefalump]

The real mystery to me is why this obsessing over reducing 1/100000 point of drag off a nearly 20 year old glider.

marc

Exactly!!

I remeber my early days of Aerotowing at Highland. I had my Quest Air tow relaease all straped down to the down tubes and keel nice and clean. Sunny performed my hang check and when he tested the relaese by pull it to simulate the tow forces and directions it spontaneously relaesed.

I had it straped too tight.

I explained I was trying to minimize drag.

Sunny looked at me ... paused ... then said ...

"I can appreciate what your trying to do with the drag ... but your flying a Falcon"

For me, it put the whole thing in perspective.

JD

[Tad Eareckson]

Jim,

Yes, thank you very much, I have always been aware that the issue is durability. Please go back and read what I said in Paragraph 5 of my 2008/01/21 drivel. (So yeah, either you didn't read it or you didn't understand it.)

Weight ALWAYS matters in any aircraft, no matter where you put it. Sometimes you want more of it to go faster forward at the expense of going faster down but it's a whole lot easier to add than subtract.

And... Can you actually cite a single example of me "prop(ping) up lack of objection as agreement"? When I say there is agreement on an issue I either put quotation marks around it or am prepared to do so.

I did mention all one of the accidents and other non-accidents caught by preflight I know about. If you or anybody else has additional references I'd love to hear about them.

Dave,

Don't use two aluminum carabiners - use one steel. The latter cannot possibly fail and the drag induced by the former is gonna hurt you a lot more than you're gonna make up for with the weight saving.

And, like I said earlier, two carabiners don't constitute a primary and a backup (unless they're of different lengths). What you get is a doubled primary/only.

Janni,

Go back and read Paragraph 9 of my 2008/01/21. I am most assuredly not promoting aluminum carabiners.

It's quite possible/probable that we would be killing more people if we changed metal. But - I would predict that we'd kill fewer of them than of those who will continue die due to failures of the stock 3/32 inch side wires we've always used. And I'm toying with the idea that the reasons would be the same - abuse and/or failure to preflight.

I don't trust my side wires. But the cool thing about that pair of components is that I can and do certify them BEFORE every flight - just like my owner's manual says. (Well, at least before I put the glider on the cart for the first time of the day anyway.) I also test them before the glider gets detensioned and goes back in the bag so I'm less likely to have an unpleasant surprise at the beginning of a good flying day next weekend.

I can't easily enough test load a carabiner in the setup area to make it worth the hassle but can use the torque wrench at home without much trouble every once in a while to load it up to more than the glider will take.


My (auto locking) steel carabiner offends me. It's just so out of proportion to everything else on the glider. I'm fine with the steel but there's just way too much of it.

After reading your post I went scouting around to see if I could find something iron based and more appropriate. The best I could do was Seattle Manufacturing Corporation's (http://www.smcgear.net) Stainless Steel Lite Locking Carabiner. Get's us down to 3.75 tons and knocks off a quarter of the weight of what I've been using.

As has been discussed, we do need carabiners to supplement our speed links in certain circumstances. I'd pounce on a three thousand pound nonlocking oval steel carabiner in a heartbeat - but in all of my searching I'm still 0 for 3 as far as any of those wish list parameters is concerned.

Crazy ol' APCO Aviation developed safe certified aluminum carabiners for paragliders. They're hot forged, expensive, and, unfortunately, not shaped for one inch webbing to one inch webbing.

So I'm just trying to learn as much as I can about the stock stuff that is available to us. And I'm drifting towards the conclusion that if it's not safe for us it's even less safe for climbers. Did you notice that ALL of the aluminum carabiner vulnerabilities cited in both the article by Rob Kells and Steve Pearson and in Marc's last post resulted from threats encountered in the climbing environment which ranged from possible to almost unavoidable - yet in hang gliding ran the gamut from totally preventable to nonexistent?

Marc,

Again - This ain't climbing. There is no freakin' way to torque or side load a carabiner on a hang glider. There is absolutely no excuse for configuring it such that in can be subjected to minor axis loading. There is no more reason and less opportunity to smack it into a rock than there is to bash your Flytec 6030.

Take a look at this:

http://www.bdel.com/pdf/S07/MM6027_A_QuickDraw_PPE.pdf

Black Diamond Dos and Don'ts

Hang gliders are doing Figure 13. That's on the Do list. If one is criminally negligent one can end up looking like 9. The only other incursion - slight - we can make into the Dark Side is 6. And that forbidden vector is limited by weak link strength and thus negligible with respect to the ratings.

There is also - as at least Janni and Dave seem to be figuring out - no freakin' way for a nonlocking carabiner to open once it has snapped closed around your glider's suspension. No, it is not obvious that there's a way for the gate to open while somebody's standing at the edge of a cliff with slack suspension. It never has been, never will be, and absolutely can't be done. Which Figure on the Don't List does it correspond to?

Try this experiment. Clip two loops of one inch webbing into a nonlocking carabiner. Grasp the loops three inches from the carabiner and try to effect a separation. Now try it again while pretending that your life depends on it. No freakin' way.

So what good is a locking mechanism doing? Zero. So what harm is it doing?

Let's go back to square one...

Brian, Luis Barradas (from the skysailingtowing forum), and yours truly agree that in a foot launch environment we can reduce the frequency of hook-in failures by moving to bolt-on suspension. (And at least two thirds of those people - including a survivor of a foot launched, hang on, tow hook-in failure - agree that the speed link is a good piece piece of hardware to use for the implementation).

It is also obvious and supported by evidence that in a platform or dolly launch environment carabiner suspension is bulletproof and bolt-on is more dangerous.

We agree that in some foot launch environments and/or conditions that the connection and dis- facility and speed afforded by the carabiner trumps the bolt-on reliability issue.

An autolocking mechanism cuts into the carabiner's ease and speed margin a little and a screw gate butchers it.

Lessee if I remember this right...

1987/12/12. A bunch of gliders were in the air when a gust front hit. One glider got blown back and ended up in trees. Danny landed in the sustained blast but couldn't disconnect 'cause a launch assistant had firmly tightened the screw gate while the suspension was fully loaded (thus making it impossible to loosen without the suspension being fully reloaded).

Now, can anyone cite a circumstance - real or hypothetical - in which a locking mechanism helped or could have? Right.

So all a locking mechanism does is cut into all but one of the launch and landing environmental safety advantages offered by a carabiner.

And again, Marc, this isn't about me trying to tweak my old glider to the point at which I can kick T2 ass. This is about getting people to think about what we're doing and why. Most people are still flying with weak links half as heavy as they should be and carabiners (when they remember to engage them) six times as heavy as they need to be.

JD,

Cable actuated release anchored at the carabiner, right? My least favorite way of doing things.

But... Nuthin' wrong with trying to clean up any glider. If you had adapted for your Falcon the system I have on my glider you'd have picked up a good chunk of speed and glide and had a safer, more reliable release that always stays in proper and tight adjustment.

Wanna talk about cleaning up a Falcon? Get in touch with Joe and see how much home brew he'll swap you for an Ultra Falcon and a time machine set for the afternoon of 2007/04/29.

Marc (again),

Kudos, by the way, to you and anyone who's got enough shit together to make something fly better. Also, it was so enormously refreshing to finally hear a hang glider jockey use the term "test pilot" appropriately.

While I've got you on the phone... I was really disappointed to hear your report of a Flytec competitor botching his bolt-on connection. Sounds doable, of course, but I'd like to really make sure that the ducks are all lined up.

I'm thinking that the only way you could have caught that malfunction would have been to have unzipped the double surface as the pilot was staging to launch. Now that I think about it - that would be the way to go with respect to launch crew checks. Is that, in fact, the standard procedure for those competition bolt-on harnesses at the flight parks and, thus, how you made the catch?

[mikel]

Enjoy this link !!!!

Should sum it up...

http://www.harrymartincartoons.com/hgpg.htm

Check out : "fear is not boring"


Have a nice day, Mike

[Flying Lobster]

Flytec meet '04. Ground crew was required to verify proper hook-in and bridle arrangement in staging line. Not an easy thing to do when getting 170 pilots airborn in an hour and a half. Particular pilot in question--who was likely Austrian but I can't say for sure--had his undersurface partially opened so that's how I made the catch.

But if it makes you feel any better, you can pretend that I'm making it up--just like you can pretend I'm making up the known instances of ropes unclipping from biners as climbers went whipping by or carabiners failing that I have personally witnessed or know of in 3 decades of climbing and Alpinism around the world.

Signing off on another arguement to nowhere,
marc