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henkvw

SLinks on tandem systems

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TomNoonan

Slinks are not allowed on Sigma tandem systems for main or reserve risers.



Just curious, is there a reason, other than "nyah, nyah, nyah, because we say so?"

From prior discussions on dz, we know the burning issue with Dacron lined mains and thus reserves. Plus the reserves have more lines than usual, creating bulk which would require custom slinks.

What about the main, if Vectran lined?

In the thread Skydiverek linked to, Mike Gruewell suggested the way the slider sat on Sigma mains tended to cause more wear at the slink area than with other mains. Or is UPT just being conservative to ensure there aren't problems with slinks not being replaced?

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Just curious, is there a reason, other than "nyah, nyah, nyah, because we say so?"



Riser damage can occur on either Dacron lined or Vectran lined canopies, or any canopy that you attach to the risers.

The other consideration is that both Slinks and Rapide links are capable of failing. When a Rapide link fails, traditionally the barrel breaks, and the Rapide link bends, but even distorted, can keep the line group relatively in tact while the TI performs EPs. The threads of the barrel screw can even hold the lines to the Rapide link, keeping the entire line group in place while EPs are performed. (Basically it is a slow speed manageable malfunction).

When a Slink fails, it is a catastrophic failure, in which the entire line group is typically lost, distorting the canopy and creating a higher speed, less stable malfunction, which increases the stress of the EP scenario.
Namaste,
Tom Noonan

www.everest-skydive.com

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piisfish

***is there even a big/long enough slinks to use for tandems??

Yes, the PD Slinks for sports reserves are also for tandem mains.

...................................................................................

PD Reserve SLinks might be big enough for tandem mains, but they do not last long enough.

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Links are normally canopy parts, not container parts. If I just happened to have a Sigma system with a Precision main that came to me used with Slinks what should I replace them with? Especially Slinks that are showing wear. No5 or No6 links? What does Precision ship them with when new?

Thanks
Ken
Always remember the brave children who died defending your right to bear arms. Freedom is not free.

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I will have to look.
The local DZ uses Icarus mains (similar to Precision) and they use #5 or #6 Maillon Rapide links. Then they wrap them with heavy cloth tape to prevent dents to the slider grommets.
#5 was the most popular size for reserves links (both round and square) for many years.
Strong has been using #6 Maillon Rapide forever on tandem mains. If you install #6 links, you could quote the Strong manual.
Maillon Rapides last forever on tandem mains, just keep some vinyl link covers handy because they wear out after 400 jumps on rear risers and 800 jumps on front risers.

When in doubt, install the larger, stronger, #6 Maillon Rapide links.

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TomNoonan


The other consideration is that both Slinks and Rapide links are capable of failing. When a Rapide link fails, traditionally the barrel breaks, and the Rapide link bends, but even distorted, can keep the line group relatively in tact while the TI performs EPs. The threads of the barrel screw can even hold the lines to the Rapide link, keeping the entire line group in place while EPs are performed. (Basically it is a slow speed manageable malfunction).

When a Slink fails, it is a catastrophic failure, in which the entire line group is typically lost, distorting the canopy and creating a higher speed, less stable malfunction, which increases the stress of the EP scenario.



Hi Tom,

Just something to think about. I've seen a rapid link distorted twice( #3,5 ). Both times the line group was held in place by the thread of the link. Both times the jumper was not aware of any of that. Both times the lines fell off the link , just second after the jumper landed and the lines were left without tension. If all of this happens and the jumper is not aware, and for whatever reason that line group is left without enough tension close to the ground ( turbulence ?) this jumper is going to have a very bad day.

I'm a strong believer that whatever breaks on your gear during skydive, should happen on opening when you are still high enough to use your reserve. Not 100 ft above the ground.

Keep in mind, I'm not a TM!
"My belief is that once the doctor whacks you on the butt, all guarantees are off" Jerry Baumchen

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Also most tandem canopies sliders are not collapsed, the flapping of the slider damages the slinks. I worked at a Dz that had slinks on all of their tandem mains, and on a slow day did an inspection and every one of their slinks had serious burns in them, some to more than 50%. We changed every slink that day. I really like the sacrificial line on the sigma canopy, its the one thing I think that every tandem canopy manufacturer would copy.


Ray
Small and fast what every girl dreams of!

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Hi
Tom, the Soft Links problems on tandem systems are known for a long time & few years.
The PD SR-1 slinks where tested few years ago but damage to the risers & slinks was found.
There is not any logic or PRO reason for using soft links in the tandem systems - the Original French # 6 SS Rapide Links are a great items for that point - it works is closed as should.
Some parts that fits into sport systems dos not fit into the tandem systems.

Cheers

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gowlerk

Why not an RDS. Passenger harness could have a pouch to stuff the drogue into.



I think that's only an option on sub-200sqft tandem canopies.
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
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