Sticky Javelin Freebag?

[JerryBaumchen 1,047]

1 hour ago, riggerrob said:

Again, you are thinking way too hard.

When urethane peels off of para-pack or Cordura, it just flakes off then falls off. Almost zero chance of it affecting the canopy fabric.

Most batches of para-pack and Cordura have urethane coating as water-proofing for the their primary roll: luggage.

The parachute industry is below 1 percent of the "rag trade" so only order small batches of fabric woven to a handful of PIA specs. (e.g. F-111 or Zero-P for canopy fabric.

Hi Rob,

Here is a fabric that I have used in the past:  Uncoated Oxford Fabric | Solarmax Fabric | Seattle Fabrics

It is an uncoated 200d fabric that IMO would make a very nice free bag.

Jerry Baumchen

PS)  I would expect that with some time searching the internet, it could be found for much less if buying in large quantities.

 

 

 

[dudeman17 268]

5 hours ago, riggerrob said:

... you are thinking way too hard.

Are you kidding me? In an environment like this I would far rather consider any possible scenario and have the questions answered before something takes me by surprise in the air. Could this melting sticky stuff infuse the material? What long term effect might that have? Someone mentioned an instance where it took 30lbs of force to pull the bag off. In a live deployment, could that cause a tear?

Yeah, I'd really rather know stuff like that beforehand.

[riggerrob 558]

Canopy fabric is supposed to withstand more than a 40 pound pull before it tears. See the tensile tests required on 1980s vintage round canopies suspected of suffering from acid mesh. Also consider that Performance Designs required all their reserves to be tensile-tested to 30 pounds for a good 30 years.

I only saw 5 reserves fail 40 pound tensile tests during the entire period that I rigged (almost 40 years). The first reserve looked more like tent fabric than parachute fabric. The second failed reserve was a 1970s-vintage square reserve built by Para-Flite, before they started using F111. Then I pull-tested holes in a pair of military surplus canopies that had a few hundred jumps as mains before they were packed into pilot emergency parachutes. The last torn reserve was made by Performance Designs and passed pull-test in a dozen other corners, so my only explanation was that it had been pull-tested twice in the same area.

Bottom line, if a 30 pound pull will damage your reserve, you are already having a bad day.

[gowlerk 1,904]

27 minutes ago, riggerrob said:

Canopy fabric is supposed to withstand more than a 40 pound pull before it tears.

And that is over a concentrated one inch of material. 

[JerryBaumchen 1,047]

18 hours ago, riggerrob said:

Canopy fabric is supposed to withstand more than a 40 pound pull before it tears. See the tensile tests required on 1980s vintage round canopies suspected of suffering from acid mesh. Also consider that Performance Designs required all their reserves to be tensile-tested to 30 pounds for a good 30 years.

I only saw 5 reserves fail 40 pound tensile tests during the entire period that I rigged (almost 40 years). The first reserve looked more like tent fabric than parachute fabric. The second failed reserve was a 1970s-vintage square reserve built by Para-Flite, before they started using F111. Then I pull-tested holes in a pair of military surplus canopies that had a few hundred jumps as mains before they were packed into pilot emergency parachutes. The last torn reserve was made by Performance Designs and passed pull-test in a dozen other corners, so my only explanation was that it had been pull-tested twice in the same area.

Bottom line, if a 30 pound pull will damage your reserve, you are already having a bad day.

Hi Rob,

To follow on dudeman17's comments; IMO it is not so much the possibility of fabric tearing as it is the potential to truly re-arrange the packing of the canopy as the bag comes off.  This also could be catastrophic.

Jerry Baumchen

[sundevil777 93]

What rigs are still using coated/lined freebag material?  Bulk reduction is reason enough to stop.

Which rigs have the freebag "exposed" by design - the Basik does, others?  They might have a reason to use more substantial material, but without the coating.

The danger is real, it happened to my rig.  It hadn't been used for a few years, the rigger found it when removing the reserve I was going to sell 30 years ago.

Edited March 15, 2022 by sundevil777

[gowlerk 1,904]

1 hour ago, sundevil777 said:

The danger is real, it happened to my rig.  It hadn't been used for a few years,

I would suggest you not jump a rig that has not been used, and I assume not repacked, for a few years. If you do jump such a rig the danger is then real.

[sundevil777 93]

28 minutes ago, gowlerk said:

I would suggest you not jump a rig that has not been used, and I assume not repacked, for a few years. If you do jump such a rig the danger is then real.

Of course.  If it can happen in a few years, perhaps it could continue to happen in the one year repack cycle of many countries.  No need to rely on inspections to prevent this problem.

[riggerrob 558]

On 3/15/2022 at 2:36 PM, sundevil777 said:

What rigs are still using coated/lined freebag material?  Bulk reduction is reason enough to stop.

Which rigs have the freebag "exposed" by design - the Basik does, others?  They might have a reason to use more substantial material, but without the coating.

The danger is real, it happened to my rig.  It hadn't been used for a few years, the rigger found it when removing the reserve I was going to sell 30 years ago.

Basik is the odd-one-out with an exposed free-bag. I have only repacked a single Basik reserve, but it went together almost as easily as a Javelin and I got it closed on my second try.

Pity, because an exposed free-bag is easier to deploy as containers get smaller and narrower in the rush to make your butt look bigger!

Hah!

Hah!

One thing that I found odd about the Basik freebag was that it had Cordura on the exposed portion, but F-111 on the hidden portion (against pack tray). I assume that Basik did that to save an ounce (gram) or two.

Ever since we got to 1990s vintage reserve densities, I have considered F-111 freebags to be silly because they are too easily damaged by ham-fisted riggers. I am amazed that more freebags are not torn by ham-fisted riggers. ??????? Yes, I have sewn patches on a few freebags made of F-111 usually after they landed in thorn bushes.

 

As an aside, circa 1980, many containers were made of only a single layer of para-pack in an effort to make them as light-weight as possible. Those single-layer containers (e.g. early SST Racer) were easy to damage by dragging across asphalt.

If you really worried about sunlight or abrassion damage, you would make the exposed portion of the freebag double or triple layer with Cordura outside and a UV blocking fabric like Dyvatane (sp?) on the inside. Dyvatane is a thick, felt-like fabric used by movie crews when they want to film "night" scenes during daytime. They cover windows with Dyvatane to block daylight. A dozen other fabrics (e.g. acrylic) can also block UV light. 

[JerryBaumchen 1,047]

13 minutes ago, riggerrob said:

Basik is the odd-one-out with an exposed free-bag. I have only repacked a single Basik reserve, but it went together almost as easily as a Javelin and I got it closed on my second try.

Pity, because an exposed free-bag is easier to deploy as containers get smaller and narrower in the rush to make your butt look bigger!

Hah!

Hah!

One thing that I found odd about the Basik freebag was that it had Cordura on the exposed portion, but F-111 on the hidden portion (against pack tray). I assume that Basik did that to save an ounce (gram) or two.

Ever since we got to 1990s vintage reserve densities, I have considered F-111 freebags to be silly because they are too easily damaged by ham-fisted riggers. I am amazed that more freebags are not torn by ham-fisted riggers. ??????? Yes, I have sewn patches on a few freebags made of F-111 usually after they landed in thorn bushes.

 

As an aside, circa 1980, many containers were made of only a single layer of para-pack in an effort to make them as light-weight as possible. Those single-layer containers (e.g. early SST Racer) were easy to damage by dragging across asphalt.

If you really worried about sunlight or abrassion damage, you would make the exposed portion of the freebag double or triple layer with Cordura outside and a UV blocking fabric like Dyvatane (sp?) on the inside. Dyvatane is a thick, felt-like fabric used by movie crews when they want to film "night" scenes during daytime. They cover windows with Dyvatane to block daylight. A dozen other fabrics (e.g. acrylic) can also block UV light. 

Hi Rob,

To the best of my rememberance, The Altitude Shop, with their Top Secret, was the first rig to use Cordura material.  It was 1000d mat'l.

I don't remember the sequence of who came along, using Cordura, after that.

Jerry Baumchen