bungee

[McRay7ac]

How many years does bungee cords need replacing - when do most Taylorcraft owners replace
replace them - Ray

[Hank Jarrett]

Re: bungee

I was told (by a supplier) to change them every 5 years, by my IA when they start to sag (and he is the one signing off the plane) and from the looks of some of the hangar queens at the airport, NEVER.

The supplier just might have a motive other than safety in mind. ;-) My IA should have my best interests at heart and has no profit motive since I change them. I change mine when he says they need changing or when I see any damage to the covers or the plane starts to feel too "soft".

Do NOT go by what the Cub guys do. Theirs are hanging out in the breeze with a fake leather sock over them. Theirs DO NOT last as long. If Chuck is still reading here he talked to the guy who actually MAKES them and I seem to remember he had some advice on this. You still here Chuck?

Hank

[mike lutz]

Re: bungee

Mine are 16 years old and just now starting to get slightly soft. Will change them next year. Also, when I put the airplane in the hangar after use, I always pick up on one side at the strut /wing attach fittings and unload the cords. I think this might help keep them less stressed as they age. Just my thought. My cords are the 9090.

[M Towsley]

Re: bungee

Hank, probably best to contact Chuck on the FB Taylorcraft page. Not sure how often he visits here, anymore.

[Mark Bowden]

Re: bungee

They are replaced "on-condition". Damage/wear to the braid covering, exposure to oil, grease, dirt and especially UV exposure necessitate replacement. If you see necking in the braid, strands below have broken. They also lose strength over time.

I have seen SBC (the only supplier) statements in the past, when properly stored there is no shelf life. Key word is "properly" as heat, too much moisture, too little moisture and UV breaks them down.

Bungee cords are generally cheaper than the aircraft parts damaged by an off runway excursion when they break on landing. Milk use out of them at peril to your wallet and shorts.

When replacing don't forget to check and replace the ax handle rubber bumpers and check that the safety retention cables are good.

Per, AC 43.13-1B, 9-4 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.

The following is a date code of manufacture chart. The date codes repeat every 5 years.
The part number is based on cord diameter in 1/16ths of an inch for 1st two digits. The second set of digits is the diameter of the cord ring shape in a perfect circle in 1/8ths.

Mark