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JerryBaumchen

For the riggers who know little about rounds

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Good correction, brain wasn't in gear - hard to have a tertiary without a secondary first!

The part I'm interested in is how it gets connected to the rig. I can see the hardware there with the snaps but how did that get attached to a PEP harness that probably wasn't designed for another parahute on the front... or was it?

-Michael

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Hi Michael,

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how did that get attached to a PEP harness that probably wasn't designed for another parahute on the front



It was not designed for an additional parachute.

I used a L-bar link on each side. Just run one leg of the L-bar link under the MLW & risers, the other leg over the MLW & risers, then I attached the length of Type 8 with the D-ring passing through the solid link; see that attached photo. You can do the same thing with a sport rig, just run the Type 8 through the slot in the large harness ring.

Jerry Baumchen

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Looking at that a couple of things come to mind. The first is that with the ring and snap floating like that they are at the perfect length to whip up and bitch slap the shit out of you on opening.

The second bigger issue is the ring. I don't think a RW8 is the right choice. First chest reserve rings like that are generally rated for 5000 lbs. The RW8 is only rated for 2500. But I think the bigger problem is how it's tested. It's designed to be loaded by a riser spreading the load over a wider area. It puts the load in almost a length wise pull down the side bars. By loading it with a snap all the load is concentrated in a very small area trying to pull out and elongate the very center of the ring. I'm not nit picking and this does not lead to just a miner elongation or distortion of the ring. The failure can be catastrophic. We've broken rings in pull test. My boss was testing some things to destruction and got "smart" and decided to use a strap with an RW ring on it to pull some thing, it was a heavy slink. But it loaded the ring sharply at one point in the middle of the ring like a snap. It plucked a peace right out of the middle of the ring. Sorry not really set up to take a picture. The interesting thing is it failed at about 1/3 the rated weight. And this was a heavy ring. An RW9 which is beefy. It's like a military ring. It's not just a question of the ring being under strength in the event of one snap coming lose. It's an issue of it possible failing as low as 1000 lb which is not cool. And if it fails like in the test it wont just bend it will snap. So their's a reason why the old chest mount rings were so beefy. Not only was it designed to survive as a single point but it loads fundamentally differently. Maybe you should rethink that strap.

Lee
Lee
[email protected]
www.velocitysportswear.com

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Hi Lee,

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the ring and snap floating like that they are at the perfect length to whip up and bitch slap the shit out of you on opening.



A number of years ago ( due to a mistake ) that setup was deployed at terminal. Nothing undue happened to the jumper. The container stayed in place ( as it should ) and the risers were mostly above his head.

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First chest reserve rings like that are generally rated for 5000 lbs. The RW8 is only rated for 2500.



The load req'ment is 5,000 lbs total; see TSO C23(b) / NAS 804. Most hardware will test out to nearly 2 times its rated load. I once recieved a letter from Pioneer that said an L-bar connector link was good for 10,000 lbs; they are rated at 3,000 lbs. And, have you ever seen the rings on a MiniSystem or a StyleMaster? They are simply a 'liteweight v-ring.'

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But I think the bigger problem is how it's tested. It's designed to be loaded by a riser spreading the load over a wider area.



I know of no TSO test that loads that harness ring. I have used 5,000 lb D-rings in the past. Then I saw a photo of a modern, current mfr's test jump ( chest pack as the 'reserve' ) and they were using this same ring in the same configuration. I studied it said, 'Sounds good to me.' I have tested these same rings in a similar configuration in tensile test machines. The webbing failed, not the hardware; webbing failure was at about 5,500 lbs/Type 8 as sewn in the photo.

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The failure can be catastrophic.



If it does, it was built incorrectly. Parachute hardware is designed to elongate before destruction. It is called ductility in the steel industry.

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It plucked a peace right out of the middle of the ring.



IMO that was an improperly produced ring. It should have deformed substantially first.

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The interesting thing is it failed at about 1/3 the rated weight.



See my previous reply.

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It's an issue of it possible failing as low as 1000 lb which is not cool. And if it fails like in the test it wont just bend it will snap.



See my previous reply.

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So their's a reason why the old chest mount rings were so beefy.



See my reply as to the rings used on the MiniSystem & the StyleMaster rigs.

I am a mfr; I hold multiple TSO's. I can test however I want. It is all part of R & D.

However, I do appreciate your comments and your concern. It does get me to thinking and it makes for a good discussion. And people do learn things.

Thanks,

Jerry Baumchen

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Clever Jerry!

While the US Army currently uses 5,000 pound snaps and D-rings to attach chest-mounted reserves, plenty of old sport rigs only used 2,500 pound hardware. All the chest-rigs that I packed for Mr. Butler had (2500 or 3000 pound) V-rings sewn to the harness.

Currently, the most popular lash-up for intentional cutaways starts with screwing RW-5 rings (3000 pound) to the main lift web. It has been a good 30 years since RW-1 rings have bent during live jumps.

If a canopy opened hard enough to bend RW-8 rings, I would not want to be awake for the opening!

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Hi Jerry, I guess you and some other riggers and skydivers could have fun to have a look at those pictures included. They are all related to round parachutes. You can see my French Paraboots, myself when student, Michael about to jump a Niagara Cloud, a round with line over, the Niagara Cloud I was packing, myself and the US Pap.
Learn from others mistakes, you will never live long enough to make them all.

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