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Sabrekakkonen

Attaching "banana type" reserve on sport skydiving container

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Is it possible to attach front-mounted round reserve to ordinary skydiving container? Hip rings would be good attaching points.


This combination would allow forexample intentional cutaway. Anything is possible, and we advance only because some people are "out of the box" thinkers.

Consider whether the harness could accept the load. Probably, but harnesses are not tested in this configuration.

Also consider whether you want to land on your head.

Please get video.

-Mark

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A few of my ideas:

Yeah hip rings seem a little low. Attaching a belly mount to chest rings would make it better, but only some rigs have chest rings.

The crude way we used to do it is just put separable D rings over the main lift web. If one really needed to use the belly reserve, the rings could slide up and maybe damage something, but it would save your life. That method didn't technically follow Canadian rules for intentional cutaways, which mention ''properly installed' D-rings, but that's the quick way people would set things up for an intentional. (I'm just mentioning my local rules as one example of how regulations may get in the way or offer good advice.)

One can also just cut up an old rig and wear the 2nd harness underneath.

If attaching a main, attach it to the new harness rings. One could skip having a container for the belly parachute, but DZO's can frown on that. (eg, exit back to wind holding PC and d-bag to belly, or have buddy direct bag you out the door. Best for high tail airplanes in case of error!) Or one can say use the cut off main container as the starting point to build a belly container to hold the main.

Or attach a reserve to the otherwise unused reserve risers on that 2nd harness.

If using 2 harnesses, one has to watch out for 2 outs, as 2 canopies pulling in different directions on 2 harnesses could cause injury. (Locally it choked one guy into unconsciousness when doing an intentional 2 out, and he downplaned onto the grass runway. Survived OK but broke things.) Canadian rules about intentional cutaways actually do mention that a 'second reserve must be worn on a single harness', although says nothing about a second MAIN canopy.

Add-on rings attached by webbing through your harness 3-ring: Another way to get rings onto a regular harness is is to build little riser like things where there's an L bar at one end, then 6" of webbing, then any harness 3-ring. Without explaining fully, the L bar goes around one's harness webbing above your normal harness ring, the webbing goes through the extra space in the slot in the 3-ring, and then the new harness ring hangs a little down below one's regular 3-rings. Now you have chest high rings to snap a belly reserve to. No sewing needed on the harness, although a rigger with a harness machine is needed to build the devices. Also seen this method used to attach a belly mount to test jump a pilot emergency rig (which won't have 3-rings, but may have a metal link in the same shoulder area of the harness).

I've also seen main risers with a 3 ring added to them, so the sewing is on main risers and not one's regular harness. That reduces the independence of the 2 mains and has thus has complicating factors about exactly what order things have to happen. Setting up cutaway handles & methods takes a little work too.

You can also set up 2 sets of mini risers side by side in your harness rings, if they are full sized ones. Seems weird but Strong had or has it on their Tridem rig built for 2 mains on the back to do an intentional cutaway.

Finally there are the actual harness modifications for extra harness rings, or a webbing loop to attach separable rings. Usually done at the factory when the rig is being built I guess. Seen it on a demo jumper's rig for giant flags or on a CRW rig for a tersh.

There have been posters on DZ who have set up just about any of these methods, and I've learned from them and built my own stuff too.

"Have fun and don't screw up!" :P

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There are many ways that this has been done. Legally it's much simpler to add an attachment point for a main or test canopy. You would like to put the cutaway canopy in the chest mount or at least the secondary main. It's harder to make the argument that that attachment point is for a reserve. It hasn't been TSO drop tested. At the very least you would have to do paperwork on it through the FSDO. Been there done that. But if it's just for a cutaway canopy then it's just a toy you're playing with in the air and as long as it doesn't compromise the TSO'd system... fair game? In any case you can generally get away with it.

Ways to do this have been discussed before. Some better then others. The example shown strikes me as a good way to get bitch slapped by that B-12 and it does not lend it self to being cut away so not well suited as a main. Could put 3 rings on it but it could still whack you. If you're making a test canopy cut away, better to put a separable three ring on there below that ring so that it would be less prone to whipping around.

What he's showing you there was probable used in TSOing that pilot rig. Probable never regularly deployed. If he did have to use it he would probable be hand deploying it past a may west or torn up canopy from an inversion as the "main" was not designed to be cutaway. It's a suitable solution for that purpose. If you ever really needed to use it in anger, like a total on the "main", a broken orbital in your eye socket would be to least of your worries. But do you want to risk loseing an eye or getting a concussion on every opening? No offence to his attachment point but you can do better. Also just as a note. RW-8's not the best ring to attach a snap to. It's not designed for that concentrated load from the thin snap. I've broken them that way. They beak at about 1/3 the normal point of failure. And yes I've built kevlar risers heavy enough to beak rings. If you look at snap rings you'll see they are much thicker or pointed to load at a small radius to match the snap. And use the heavier snaps designed for reserves. They're rated for higher loads. It's assumed that one may come lose. And cross connectors. If you're going to build risers for a belly mount reserve don't forget them and build it in a non pealing way that could survive an opening on one snap.

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Good point on the point loading of harness rings - obvious in itself but its practical effect was unclear. Most of us don't have specs on that kind of stuff, beyond "it's good for X proof load". Something for me to consider.

(I went back and looked at the RW-1-82 bulletin on weak rings, and even there they used webbing folded to 1" wide to do the 2500lb proof loading of the harness ring.)

You were wondering about getting bitch slapped by the B-12 if one has rings to attach a belly mount, on a section of webbing. Ok, that's at possible hazard.

Yet I do have a rig from the '70s with extensions for the belly mount attachments, giving a similar geometry. I think the idea is to load you more vertically (if the belly mount is used) by pulling from the shoulders, without having the belly mount sitting just under your chin. A photo is attached. It wasn't TSO'd as it is from Canada. If the belly mount is used, the short riser hidden under the mudflap pops the snaps and rotates up from the Capewell attachment point.

So I wonder, were there American rigs built like that too?

Anyway, that rig suggests that even if Baumchen's method does have its hazards for your face, a similar configuration also existed on some regular belly mount rigs in the '70s.

Thanks.

CIMG4955 Niagara rig (med).jpg

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Hi Lee

Quote

Legally it's much simpler . . .



Maybe for you & other riggers. I own AeroSports USA & hold numberous TSO's. Therefore, I can do just about anything I want while developing equipment. There is no FAA limit; unless I make a lot of jumps on something.

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The example shown strikes me as a good way to get bitch slapped by that B-12



That very configuration has been jumped, in an emergency ( at terminal ), with no injury to the jumper. IMO test jumping, by it's very definition, has risk. That's why they get the big bucks. ;)

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RW-8's . . . I've broken them that way.



Tell me more about this. At the '93 Symposium, ForgeCraft did a seminar on making hardware. They showed some photos of how they proof tested various hardware pieces. For almost everything, they had a specific test jig(s) that would spread the load forces all across the hardware; rather than a point load as a snap does to a d-ring.

I would really like the details on any hardware that you have broken under the loads that it is rated for.

And I really do appreciate your input on this type of stuff.

Jerry Baumchen

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In regards to the testing. Most of the interesting points were actually side affects of our efforts to find ways to test other things. For example we were looking at using "super slinks" in some aplications. Big mongo sized kevlar slinks made from basically light kevlar rope. Found a number of issues. One being that slinks become less reliable as the diameter of the material they are made from increases. As the line or cord increases in diameter there is a rolling force trying to flip the ring through the knot. It tries to unlock it self. At the loads we were playing with it's an issue. Some of the hard ware problems showed up as Phil was trying to test the super slink. We built a 20,000 lb test stand with load cells and a hydrolic cylinder. The high speed video of the stretching and failure of the joints was very interesting. Phil was pulling all these weird things. I was building test samples for him. He was using any thing he could rig up to pull them. Like for example using RW-9 rings to try to break the supper slinks. On paper they were stronger then the slink but with the load concentrated on that little half inch space in the center of the ring he plucked a .5 inch bight out of the middle of the ring. And the RW-9 is actually a pretty beefy ring. Heavier gauge then the RW-10 that you see on most tandems. We started pulling some of the hard ware and risers that we were building and found that the rings needed to be loaded across a wider area to reach their tinsel strength. We were also looking at the strength of our big kevlar 4 ring risers and found failure points at the second ring where we would just bend and wrap the second ring around the first. It was difficult but we could sew kevlar risers that would not break but the limiting factor was the ring hardware. We wound up going with a different design. It was sort of like an old strong wrap with the end being held by a three ring. Finally in the end we just designed a strap cutter. Think big cypres cutter that cuts 15,000 lb kevlar webbing. It's field re loadable with smokeless powder and electronic igniters. That made all the problems go away.

As to the results of the hard ware testing. Most of the failures that we generated were in trying to miss use it in some other way. As such I didn't really keep notes on it. We did find a bad ring that had some kind of fracture in it. They were left over RW-9s that we got from paragear. Might have even been seconds? They had been made by forge craft probable at the very end. I showed them to the guys from Borden Forge at the symposium. They said that the tooling was worn out when it was made. They had no problem diagnosing the fracture. They are the new maker of that ring and had had to make all new tooling for the contract. They were not surprised at all by some of the other failures like the rings with the half inch bites out of them. They were never intended to be loaded in that way and were not surprised at the numbers I quoted to them for the failure points. I don't remember them off the top of my head but 1/3 sticks in my memory. It was in interesting lessen in testing and the use and miss use of hard ware in ways that it was not designed for. Loaded properly Every thing did well, with the notable exception of that defective ring. Being miss used all bets are off. So when I see people for example a base rig manufacture using RW-8s for harness attachment points for base tandem rings I start jumping up and down pulling my hair out and screaming, "NO, NO, NO!"

Lee
Lee
lee@velocitysportswear.com
www.velocitysportswear.com

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Hi Lee,

Quote

On paper they were stronger then the slink but with the load concentrated on that little half inch space in the center of the ring he plucked a .5 inch bight out of the middle of the ring.



Do you know at what load this occurred?

I did a quick search of my hardware drawings and found one for the large 3-ring harness ring. It is a DJ #445 and the drawing does not have a load rating on it. I find this somewhat odd as all of my MS hardware drawings include load ratings.

I did find that ParaGear says the RW-8 is rated at 2,500 lbs. http://www.paragear.com/skydiving/10000174/H3800B/

And then on the RW-10 ring they do not list a rating. http://www.paragear.com/skydiving/10000174/H3820B/

Always interesting stuff to find when we go looking.

Jerry Baumchen

PS) Also a quick search of all my load testing reports, I find that I have never tested a 3-ring ring of any size.

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