Hard cutaways; their causes and prevention

[Hooknswoop 19]

Twisted risers. The number one cause of hard cutaways is when the canopy has line twists that include the risers and the excess cutaway cables on the back of the rear risers. The friction that is created can high enough that the jumper is unable to cutaway. The solution is capped, tacked hard housing inserts for the excess cutaway cable on the back of the rear risers.

Lack of 3-ring maintenance. Completing the 3-ring maintenance every 30 days keeps the 3-ring working at it's best. It will take more and more force to release the longer it goes without maintenance.

Dirty cutaway cables. This is important and has a very big impact on cutaway forces. Cleaning the cutaway cables every 30 days with Ace Pure Silicone Lubricant keeps friction between the cables and housings low.

Nicks, bends or cracks in the cutaway cables. Any sort of damage to the cutaway cables, especially at the locking loop or above can dramatically increase cutaway forces. Replace damage cutaway cables with a new handle.

Cutaway cable housings too short. If the cutaway cable housings are too short, they put stress on the locking loop, changing the geometry of he 3-ring and putting more friction on the locking loop. Relative Workshop's web page contains information on how to inspect your housing for length.

Mini rings. Manufacturing tolerances for mini rings are tighter than standard rings. Even correctly manufactured mini rings do not have the mechanical advantage of standard rings, resulting in higher cutaway forces. Have the construction of your 3-rings checked, or check Relative Workshop's web site to check them yourself or use standard risers.

Incorrectly manufactured risers. 3-rings must be manufactured to tight tolerances in order to get the maximum mechanical advantage. Have the construction of your 3-rings checked, or check Relative Workshop's web site to check them yourself.

Twisted cutaway cable housings. If the cutaway cable housings are twisted, so that they are facing away from the riser, the twisting force adds tension to the locking loop, adding to the cutaway force. Have twisted housings fixed.

Soft housings. Soft housings create more friction between the housing and cutaway cables than hard housings. Have your rig converted to hard housings if it has soft housings.

Derek

[rgoper 0]

following these basic rules of "gear maintenance" saved me once. on jump #474 line twists all the way to the risers, the slider was still at the top of the canopy, which was fully inflated, i knew i didn't have the altitude to see if i could kick out, that and i was spinning on my back, i had an easy cut-away (one hand on each handle) i attributate this to the training i recieved. i also utilize hard housings, no RSL.

excellent post!

--Richard--
"We Will Not Be Shaken By Thugs, And Terroist"

[skymick 0]

Great post, I generally clean my cutaway cables using an oil based product. im guessing the oil can cause crap to stick to the cable though if not fully wiped off after cleaning. Can that cause a problem?

[FeFe 0]

link to RW housing article for us lazy people


.

[billbooth 10]

Derek;

That's the best 3-ring problem summary I've ever seen.

Thanks, Bill Booth

[jumper03 0]

Quote

Lack of 3-ring maintenance. Completing the 3-ring maintenance every 30 days keeps the 3-ring working at it's best. It will take more and more force to release the longer it goes without maintenance.

For the still (and always) learning - what exactly is involved in 3-ring maintenance?

(If it's on the pages you posted - apologies. Haven't had time to check them out yet)

Jump

Scars remind us that the past is real

[Hooknswoop 19]

Quote

what exactly is involved in 3-ring maintenance?

Relative Workshop's web page, http://www.relativeworkshop.com/, has their V3 manual which covers 3-ring maintenance. In short, every 30-days, disconnect the 3-ring and 'massage' the webbing to prevent it from taking a set. Clean the cutaway cables with Ace Pure Silicone Lubricant.

Derek

[RippedCord 0]

Quote

Clean the cutaway cables with Ace Pure Silicone Lubricant.

I searched for "Ace Pure Silicone Lubricant" lubricant on the web and got some DZ.com results as well as results for condoms and sex toys. Would WD-40 work just as well, or would it be better to use nothing?

AMDG

[rigging65 0]

WD-40 can breakdown, and also tends to attract dirt a bit more than Silicon lube does. Regardless of what you use, wipe off all the excess...you don't need much on there when you're done!

"...and once you had tasted flight, you will walk the earth with your eyes turned skyward.
For there you have been, and there you long to return..."

[Hooknswoop 19]

Ace Hardware stores sell it. It is in a standard spray can with a clear cap. $5.00-ish. I used to use WD-40 and silicone is much, much better. It leaves a dry slick film behind. I would never use WD-40 again.

Derek

[kallend 2,027]

Quote

WD-40 can breakdown, and also tends to attract dirt a bit more than Silicon lube does. Regardless of what you use, wipe off all the excess...you don't need much on there when you're done!

WD40 gets quite waxy/sticky when it is left for a few months. It's OK on parts that are constantly moving, but not good for parts that sit immobile for long periods of time. Also, it's petroleum based, which is generally not good for synthetic polymers (such as nylon fibers, aramids, etc.).

...

The only sure way to survive a canopy collision is not to have one.

[michaelflying 0]

Thanks for the info.

www.skydivekzn.co.za

[ZigZag 0]

I am still looking to build a tool that can clean the inside of cable housings without a cleaning wad getting stuck inside or damaging the ferrules on the ends. But in the meantime I found that dry silicone lubricant works best. I concur.

[Hooknswoop 19]

I have seen flexable gun-barrel cleaners at sports stores and have considered buying one to see how well they work on housings. Maybe I'll have to get one.

Derek

[nightjumps 1]

Quote

I have seen flexable gun-barrel cleaners at sports stores and have considered buying one to see how well they work on housings. Maybe I'll have to get one.

They work OK, not great. I went back to using the mechanic's air hose to give the housings an air blast.

[cssriggers 0]

To add our $0.02 we've always used silicone on cutaway cables in our loft; usually the Prestone brand (worked fine.)

We bought some "GUNK" brand silicone on sale at a Home Depot once and it was so tacky/sticky we wouldn't use it.

Then on an emergency pre-boogie supply run, we accidentally bought some "Ace" brand silicone. (Why accidentally? Well, we were busy, and it was closer + more expensive ... we're out in the boonies here.) This was a few weeks before "Derek's gear tips" was posted on this site.

It's hard to explain, but if you clean a lot of cutaway cables like we do, you'll quickly find that the "Ace" brand of silicone is cleaner, drier, smoother and less tacky than anything else we've found.

It was kinda cool seeing our findings backed up by the experts.

WD40 is bad because it's so tacky, it attracts a lot of dirt. I've heard that 3-in-1 oil is OK if you wipe the cables really dry.

Edited to add:
Cables treated with Ace silicone seem to remain cleaner at the next repack cycle as well

Alpha Mike Foxtrot,
JHL

[Scrumpot 1]

"DuraLube" makes a 100% silicone spray lubricant that has worked well, with pretty much the same basic attributes (non-dirt attracting DRY, yet "slick" film which does NOT seem to "build up") as I'm seeing be reported with the Ace brand. FWIW.

coitus non circum - Moab Stone

[Hooknswoop 19]

Bill Booth posted about Ace Pure Silicone Lubricant back in Oct, 2002. I got the idea from him. He gets the credit.

Derek