replacing bungees (need advice)

[markc]

hey guys the piet I purchased in the spring (n799jk awesome plane built by my friend jimmy boy ) has had the same bungees on it for 17 years and they are finaley due to be changed they are hand wrapped kinda like a cub strut but the hooks are not 90 degrees from each other ,I am going to measure the OD of cord in the morning but need some advice on the best way to wrestle this baby PLEASE HELP ! mark , air2mcc@yahoo.com

[Clay Hammond]

Use an engine hoist.

http://www.supercub.org/forum/showthrea ... -how-I-did

Everyone has an engine hoist available to them with just a little asking somewhere within a half mile of any hangar. If a little common sense is used, with a healthy respect for stored energy and proper support materials, it is a simple and painless way to do a bungee change without specialty tools and without danger of bodily harm. Simple and proven.

[markc]

Clay thank you for the advice , I guess I should have been precise in the help I needed , I am an I/A and changed many shock cord rings but have never hand wrestled mil-5156d type 1 , 5/8 by hand and was looking for advice on tying the loops and also Ho to pretension 6foot of cord while wrapping around shock strut while also keeping them equal ?
Hope u can advise on this clay ?

[markc]

[Tools]

Hey mark,

Can't be too much different than doing the straight axle bungee. First, wrap a bungee without tension and see how the length compares the tensioned one. Should demonstrate about 10 percent stretch. Just a warm fuzzy sort of thing to know.

Just pull as you go, two pairs of hands. Once done, just zip tie with a couple of zip ties. It will easily hold adequately so you can then wrap how ever you want. While not pretty, two automotive hose clamps will work fine. At least mine have for years and years.

Stainless safety wire and a solid half inch or
More of wrapping should work and look a lot nicer.

Using the old one to measure the new one and confirming you end up with the requisite number of wraps and all will confirm you have the same amount of stretch as the old one.

Mike

[markc]

Thank you mike for ur input it seems the way I will probably do it I was just thinking that they needed to be tensioned more than what I can do by hand , I am overthinking it I'm sure , would dipping the shock cord in Hot water make it more pliable to actually tension it easier ?

[Clay Hammond]

Agree need two sets of hands to make it go easy. We wrap bungees here at the Aerodrome by hand all the time...you just need a helper to assist.

[jklemin]

My Piet, acquired in many pieces, didn't have the bungees. Would someone like to tell me what size the cord should be? It may be in the manual, but the one I ordered has gotten lost in the mail (at least the dog didn't eat it). Approximately how long should I start with? Thanks. John

[markc]

I replaced mine with 1/2 in cord about 13 ft did both sides I can get a measurement off my old one I think it is still at the hangar if you need

[yellowing]

hey Markc....I just replaced my shock cords...used 5/8 cord from aircraft spruce ...used 7.5 feet per side....when i put my first passenger in the front seat the old cords give out..so I put an extra wrap and hope that will work..If that doesnt work I mite have to try a different type of landing gear.....I see piets have different types........yellow wing

[markc]

U are a bad momma jammer if u wrapped that 5/8 cord by hand, I tried with gloves and clamps and even some help and it kicked my a###
So I put the 1/2 " on and I think I got 3 1/2on front and 3 1/2 on back thumbs up to u HEE MAN

[yellowing]

markc....ya had a 250lb. helper with a big vice.......ya the plans call for a 5/8 cord....we managed to get 4 on front and back...hopeing it will do it and not be to stiff........yellow wing