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01-25-2020, 03:31 PM
#181
Re: Bungee Installation
I don't remember where I found this. Good info.
Shock-Cords.pdf
Last edited by DaleLindstrom; 01-25-2020 at 03:33 PM.
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01-25-2020, 04:28 PM
#182
Re: Bungee Installation
I was pretty much aware of that, wasn't complaining about the age just giving it as a reference given that Justin got some that were about four years old and was concerned about it a week or two ago...
Originally Posted by
DaleLindstrom
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01-26-2020, 08:40 AM
#183
Administrator
Re: Bungee Installation
Originally Posted by
DaleLindstrom
Good information, learned some new stuff. Thanks.
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01-26-2020, 11:56 AM
#184
Re: Bungee Installation
Originally Posted by
doc
I was pretty much aware of that, wasn't complaining about the age just giving it as a reference given that Justin got some that were about four years old and was concerned about it a week or two ago...
Yes, good information. But, a 5 year automatic replacement recommendation seems a bit too soon. Of course, replacing if there is wear showing.
I saved a copy of this information for my files. Thanks
"You can only tie the record for flying low."
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01-26-2020, 03:38 PM
#185
Re: Bungee Installation
Originally Posted by
ysifly2
here's the actual mil-spec that is referenced in the Univair document...
Attachment 11761
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01-26-2020, 05:40 PM
#186
Re: Bungee Installation
I think that mil-spec refers to the manufacture of the shock cords. Once manufactured, they can be stored under proper conditions for a considerable period of time.
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01-26-2020, 06:32 PM
#187
Re: Bungee Installation
Originally Posted by
DaleLindstrom
I think that mil-spec refers to the manufacture of the shock cords. Once manufactured, they can be stored under proper conditions for a considerable period of time.
The mil-spec gives the manufacturer 6 month from manufacture to delivery to the end user ( assuming a government contract). If the vendor is advertising shock chords that meet the mil-spec, or if your PO specified they had to meet mil-spec, then anything over 6 months doesn’t meet the contract.
Sent from my iPad using Tapatalk
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01-26-2020, 06:40 PM
#188
Re: Bungee Installation
Originally Posted by
dgapilot
The mil-spec gives the manufacturer 6 month from manufacture to delivery to the end user ( assuming a government contract). If the vendor is advertising shock chords that meet the mil-spec, or if your PO specified they had to meet mil-spec, then anything over 6 months doesn’t meet the contract.
Sent from my iPad using Tapatalk
I read it that the rubber used in the manufacture of the cords could not be more than six months old.
I understood it to be a manufacturing mil-spec.
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01-27-2020, 04:13 PM
#189
Re: Bungee Installation
The date issue is pretty confusing since later in the Univair document above it states:
There is no specified shelf life. SBC sent us correspondence in 2000 stating:
There is no prescribed limit on shelf life. As long as the Superior Rings
are kept in a controlled environment with low relative humidity and out
of UV light, they should keep for periods longer than we could
reasonably record data. An excessively dry condition of storage can
eventually cause dry-rot of the rubber core. Conversely, an excessively
damp condition can cause rot of the cover material. We have had rings
in the field in place on an aircraft last greater than 20 years. It is
therefore reasonable to assume that non-extreme conditions in a
warehouse should yield a shelf life more than sufficient to inventory our
product until resale.
Advisory Circular, AC 43.13-1B, 9-4 (a) states:
a. Old aircraft landing gear that employs a rubber shock (bungee) cord
for shock absorption must be inspected for age, fraying of the braided
sheath, narrowing, (necking) of the cord, and wear at points of contact
with the structure and stretch. If the age of the shock cord is near 5
years or more, it is advisable to replace it with a new cord. A cord that
shows other defects should be replaced, regardless of age.
Kind of makes you wonder why they require the date code woven into the ring if the Mfg date is unimportant -since it doesn't have a shelf life. Even then, at 5 years (installed) it is only then "Advisable" to replace, not required, and that would be based on install date and not the original Mfg date.
Replace when they wear out and/or sag. The color code is useless.
“Seek advice but use your own common sense.”
― Yiddish Proverb
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01-27-2020, 04:40 PM
#190
Re: Bungee Installation
Has anybody used or anyone know if you can use a bungee tool like this for installing bungees on a hydrasorb type shock for a PA-22? https://secure.steenaero.com/Store/s...DF2A6172891E71
I fly because it releases my mind from the tyranny of petty things
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