Gear component load limits on rigs

[cvfd1399 0]

I know rope rescue, and the saying with us is that the system is only as strong as the weakest link. Ie rope rated at 5000 lbs harness rated at 4000lbs, rigging plate 10,000 but 1 d-ring rated at 2000 lbs brings the whole system down to a max loading of 2000 lbs. With that being said I am looking for a site that has all the gear compontents listed out with their load limit. Ie type webbing-3000lb, d-ring 1000lbs mini risers 300 lbs regular risers 500lbs. Just for personal knowledge on what is the weakest link on our gear so I can pay attention to them, and identify the danger points.
Paragear has a good listing of this under the riggers supply part of their site, anyone else got a better source.

[PhreeZone 15]

Depends on your container manufactor. Some use different webbing and hardware.

Almost always the chest strap hardware is going to be the weak link. I think its only rated to 500 lbs.

Big thing to keep in mind is that like rope rescuses its easy to shock load the system. A hard opening might put a load of 3-4+ G's on the system for split second.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[propilot 0]

Intuitivly, I would think your best chance at finding ratings on certain components would be to contact

A-The manufacterer of the rig
B-The supplier

Also, its important to realize that different manufctrs. might get their components from different suppliers, so you would need to research a specific rig/component.

[NightJumper 0]

Quote

Almost always the chest strap hardware is going to be the weak link. I think its only rated to 500 lbs.

Boy, I'm glad I'm not jumping that gear.You also should know that the chest strap only takes 8-15% of the load.

[ryoder 1,384]

Quote

Depends on your container manufactor. Some use different webbing and hardware.

Almost always the chest strap hardware is going to be the weak link. I think its only rated to 500 lbs.

Big thing to keep in mind is that like rope rescuses its easy to shock load the system. A hard opening might put a load of 3-4+ G's on the system for split second.

The chest strap is not a load-bearing component, so it's strength is irrelevant.

At the PIA riggers convention some years back, there was a discussion about component strength, and Booth brought up the principle of the "fusible link". The point is that you don't necessarily want every component as strong as possible. You may want a particular item to predictably fail before another. e.g.:

- You may want your main risers to fail before your harness, else a destructively hard opening could make your reserve useless

- You may want your main risers to fail before they transmit a fatal opening shock to your harness, else a really hard opening could kill you. If they fail on such an opening, you can still use your reserve.

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[nitrochute 2]

chest strap only takes 8- 15 % of the load under ideal conditions. but head down is another story. bout 10 years back a well known mfr. was doing some drop tests of their new rig. dummy opened head down,and the chest strap failed allowing the dummy to fly right out of the harness.

[cvfd1399 0]

I know all gear uses different components. I am looking for all items listed ie
b12 snap=
webbing type 1=
webbing type 2=
tacking thread=
binding tape=
friction adapter type? =
ECT........

[PhreeZone 15]

How much is the chest strap hardware rated to then?

In this post Mick Cottle the designer of the Reflex states its only mil spec for 500 lbs:

http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=929949#929949

Quote

The true "weak spot" on the chest strap is the hardware. the MS 70101-1 quick fit adapter (for 1 3/4" webbing) is only rated at 500 lbs, which is still more than you need.

In this post Sparky says the same thing http://www.dropzone.com/cgi-bin/forum/gforum.cgi?post=1192522#1192522


Chad, you might also look into what each stitch pattern is rated for. In the archives of here a few rig manufactors are stating that the stitch pattern could fail before some webbing types do.


This is not directed at you Mike, but I've noticed lately that there are an increasing number of people that are super fast to point out an error, but they never offer up an actual answer to the questions.

Yesterday is history
And tomorrow is a mystery

Parachutemanuals.com

[skybill 18]

Hi 1399,
Ya' gotta' look at the big picture. The geometry of the whole rig is designed to take "X" shock load at "X" MPH with "X" lbs. in the saddle. If you want to get into the values of parts, get a Poynters manual and start reading. FYI the Lbs. rating on webbing, tapes, etc. is done by pulling the test sample apart in a test machine where the jaws are pulling the sample at a "constant" rate of 3 inches per minute!! Lots of fun, a piece of T/VII sounds like a .45 pistol going off when it finally breaks!!! Also, the "given" value is the minimum strength rating. Another piece of engineering fun is calculating joint efficiency. Look at the bottom of your canopy and figure out the "joint efficiency" of where one suspension line attaches?? Where's the weak link there? In the attach loop? In the loop of the susp. line? At the insertion of the loop of the susp. line? At the "end" of the inserted piece of the susp. line? Try the "end" of the inserted piece of the susp. line!! Notice the taper of the inner piece, the longer the better! A blunt cut is bad stuff. Run your fingers down the insertion on your lines down to the taper. If it is smooth like the inside piece is cut at a shallow angle (45 deg. or less) it's ok. More, (blunt) bad news. Onward and upward, get your Poynters Manual and start reading!!!!

SCR-2034, SCS-680

III%,
Deli-out

[cvfd1399 0]

Thanks guys I really like this part of the sport. I also know that when a piece of rope is bent around a object(as on a friction anchor) we require that the object has to be 3+ times the diameter of the rope. B/C the rope looses it's strength if it is bent at a more severe angle. I suspect this has to be true for the suspension lines as they go on the rapide links. I am not certian of the measurements, but the links seem near the same size as the lineset ends. Is that kind of thing part of what goes into "calculating joint efficiency"?

[skybill 18]

Hi again 1399,
You're getting there. Like I said, get a Poynters Manual, it's the where you will find just about everything you want to know about how parachutes are built but didn't know where to look or who to ask book. Have fun.

SCR-2034, SCS-680

III%,
Deli-out

[riggermick 6]

Quote

Hi 1399,
Ya' gotta' look at the big picture. The geometry of the whole rig is designed to take "X" shock load at "X" MPH with "X" lbs. in the saddle. If you want to get into the values of parts, get a Poynters manual and start reading. FYI the Lbs. rating on webbing, tapes, etc. is done by pulling the test sample apart in a test machine where the jaws are pulling the sample at a "constant" rate of 3 inches per minute!! Lots of fun, a piece of T/VII sounds like a .45 pistol going off when it finally breaks!!! Also, the "given" value is the minimum strength rating. Another piece of engineering fun is calculating joint efficiency. Look at the bottom of your canopy and figure out the "joint efficiency" of where one suspension line attaches?? Where's the weak link there? In the attach loop? In the loop of the susp. line? At the insertion of the loop of the susp. line? At the "end" of the inserted piece of the susp. line? Try the "end" of the inserted piece of the susp. line!! Notice the taper of the inner piece, the longer the better! A blunt cut is bad stuff. Run your fingers down the insertion on your lines down to the taper. If it is smooth like the inside piece is cut at a shallow angle (45 deg. or less) it's ok. More, (blunt) bad news. Onward and upward, get your Poynters Manual and start reading!!!!

Bill (fuckin) Delli,
I thought you were dead!!!!!! It's been a long time no see or hear. How the heck are you ???????? drop me a line
@ [email protected] I'd love to catch up. Best wishes . Mick Cottle.

[BlindBrick 0]

Ok, got a related question for you all. If we know that the chest strap friction adapter is rated at 500 lbs, what would be a good replacement for those of us that like to lay base on hybrids? I know the adapter should hold, but I've had a few decent yanks on my cheststrap, and could easily imagine a larger jumper, like myself, putting 500 lbs of stress on the strap.

Also, as just a sr. rigger,I'm not familiar with the legalese of such a mod. Would you need to do a TSO re-cert or is there an equivalent of the STC for rigs?

-Blind

"If you end up in an alligator's jaws, naked, you probably did something to deserve it."

[cvfd1399 0]

I agree, we have hardware and webbing that can hold more than that. Even though It might not take that kind of a load during a normal skydive, If I made a rig I would plan for anything skydivers would try. Unless like posters stated above that it is designed to be weaker for safety ie risers, but I am can't figure out a situation where you would want a chest strap to fail.

[neandertal 0]

I still jumping with my Racer.
Type XIII (MIL-SPEC) is a factory standart.

No Drogue, no JUMP!!

[markbaur 0]

Quote

I'm still jumping with my Racer.
Type XIII (MIL-SPEC) is a factory standard.

Racers use Type 8 for rear reserve risers, chest strap, diagonals, and laterals.

Where Racers use Type 13 instead of Type 7 or doubled Type 8, they do so for better compatibility with leg strap friction adapters, not for strength.

Mark

[NightJumper 0]

Quote

Where Racers use Type 13 instead of Type 7 or doubled Type 8, they do so for better compatibility with leg strap friction adapters, not for strength.

Yes, it is for strength also.

Mike Forsythe
Jump Shack

[markbaur 0]

Type 7 is rated at 5500 pounds and has been in successful use in the sport market for years. Choosing Type 13 because it is rated at 6500 pounds sounds like marketing, not engineering.

I just packed a competing rig, on which all the reserve risers were Type 7. Why does Jump Shack use weaker Type 8 for rear reserve risers in this critical application?

Mark

[NightJumper 0]

Quote

Choosing Type 13 because it is rated at 6500 pounds sounds like marketing, not engineering.

Nope, BOTH engineering and marketing. You already pointed out the other engineering advantage in your previous post.

Quote

I just packed a competing rig, on which all the reserve risers were Type 7. Why does Jump Shack use weaker Type 8 for rear reserve risers in this critical application?

Because in thirty years it has never failed and is part of the TSO I would think, but I will find out tomorrow.

Now my question to you is why does your "competing" rig use the "weaker" type 7 or 8 on the harness that is used every time you use the container, or is this not an “critical application”?

[riggerrob 558]

Quote

Type 7 is rated at 5500 pounds and has been in successful use in the sport market for years. Choosing Type 13 because it is rated at 6500 pounds sounds like marketing, not engineering.

I just packed a competing rig, on which all the reserve risers were Type 7. Why does Jump Shack use weaker Type 8 for rear reserve risers in this critical application?

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>.

That competing rig probably had chest and/or hip rings. In that case, it is simpler to make the main lift web and reserve risers out of a single piece of webbing. Try picturing an extra-long set of reserve risers that wrap around the hip ring.

In another case, Racer uses Type 8 rear reserve risers because they are strong enough and using thinner Type 8 makes it easier to sew the confluence just below the 3-rings. The shoulder joint is the thickest part of the harness, with MLW, diagonal back strap, two reserve risers and 3-Ring loop all sewn together, 5 layers of webbing.

Single layer Type 8 is strong enough for reserve risers and doubled Type 8 is more than strong enough for MLWs, it is just not very durable. Most MLWs have a layer of Type 7 or 13 - on the front - for abrasion resistance.

• Quote

[markbaur 0]

Quote

Now my question to you is why does your "competing" rig use the "weaker" type 7 or 8?

Because Type 7 or Type 8 (in some parts, doubled Type 8) is strong enough, and because friction adapter tests show Type 13 is not significantly better than Type 7 in resisting slippage.

Mark

[mjosparky 3]

Quote

I just packed a competing rig, on which all the reserve risers were Type 7. Why does Jump Shack use weaker Type 8 for rear reserve risers in this critical application?

Using Type 8 for the rear riser and Type 7 for the front riser is a carry over from a time when there were no riser covers. When packed the front riser covered the rear riser, thus protecting it from the effects of UV. Because it, the front riser, was exposed to UV it was made of the stronger webbing to help offset the damage.
At least that is the way it was told to me, many years ago, when I asked.
Sparky

My idea of a fair fight is clubbing baby seals

[NightJumper 0]

Quote

and because friction adapter tests show Type 13 is not significantly better than Type 7 in resisting slippage.

I disagree, type 13 is superior in slip resistance. This is a proven fact. Type 13 was designed for the friction adapters. And for not more than a couple of dollars a harness what not use a stronger less slipping webbing? Also, why do the same manufactures that don't use type 13 on their sport containers use type 13 on the military versions?

[masterrig 1]

Hello, NightJumper!

I have a question for you. Weren't the friction adapters in common use on harness' today, originally used on very early cotton webbing for harness' and that Type 13 webbing is woven in a similar pattern?

Chuck

[NightJumper 0]

Quote

Weren't the friction adapters in common use on harness' today, originally used on very early cotton webbing for harness' and that Type 13 webbing is woven in a similar pattern?

Yeap, you are correct. I was in a hurry, it should be that type 13 was made for the adapters, thanks.

Stay safe,
Mike