Bungee Cords

[Pearson]

My landing gear are sitting wider than usual after I get out of the plane. So I ordered a set of new cords. $146 from Spencer Aircraft in Olympia, WA.

They have one blue stripe and two red ones. Using info gained from this great site, I THINK I have figured out that they were made in the second quarter of 2008. Can someone back me up on that?

Instead of the usual part number for a BC12D, I asked for the HDX version. I know this has much less give on landing, but I am willing to sacrifice that for longer wear. I don't mind changing bungees every 5-6 years, but I am not getting that long out of the standard ones. If anyone is interested in how they work out, I will be glad to report.

One thing that bugs me is fraying of the outer covering on the cords. I think mine are fraying from the end of the safety cables that stick out just a little from the swage. Has anyone else had this problem? Does wrapping the end of safety cable with some sort of tape do any good? Or does it just rub off after a couple of landings. I think I could get much more life out of my bungees if I could cover these frayed ends of the safety cables. The last time I replaced the cords I put the swage in the vertical so that it would not be compressed between the cord and the bumper or part of the landing gear. But it didn't do much good.

[Robert Lees]

Re: Bungee Cords

Richard, what diameter and radius are they?

[Pearson]

Re: Bungee Cords

If you are asking about the cords, they are the original 9/16" X 10". The safety cables I am not sure about what size they are. The ones on my project plane look like 3/16" and the ones on my other plane, are larger....maybe 1/4".

[Robert Lees]

Re: Bungee Cords

Richard,

I use one 9010HD and one 1110 per side. The photo shows the difference is diameter (if you can tell!).

The stiffer ride improves the "wobble" when taxying across uneven ground (and lessens the tendency to lift a wing in crosswinds). Doesn't flatter untidy landings, though, as you say.

I don't use a stop cable at all....as you say, all they do is wear the bungees before their time.

[Pearson]

Re: Bungee Cords

that is why I am going to use the HDX version of the 9010s. They are almost twice as stiff as regular 9010s. I have never heard of anyone NOT using the safety cables. After having them on for so many years, I don't know if I would feel comfortable knowing that if a cord breaks my gear would collapse.

Is anyone else NOT using the safety cable??

Has anyone else had a problem with the safety cables chaffing the bungee cords?

[Dick Smith]

Re: Bungee Cords

I wrap my safety cables with a good grade of 3M electrical tape...It makes the cables less abrasive where they rub against anything. You can also consider wrapping the frazzled strands of cable that protrude from the end of the Nicopress fitting with some .041 S.S. safetywire, to eliminate some of the cutting action...then wrap it with the slick electrical tape. Dick

[Mark Julicher]

Re: Bungee Cords

The neatest trick I ever saw with safety cables was putting some heavy duty shrink-wrap over the swage. Much heavier stuff than electrical insulation is available. Unfortunately, this must be planned for before the cables are swaged.

[Robert Lees]

Re: Bungee Cords

I have never heard of anyone NOT using the safety cables.

Now you have, Richard. At my field, we have three Taylorcraft so equipped (soon to be five, the next time the other two need bungee replacement) ; all undergo annual inspections that include a thorough checking of the bungee condition.

With the 1110 and 9010 combination, we found the bungee failure rate dropped to zero when we took off the stop cables (but we do replace the bungees when the undercarriage starts to show signs of drooping). Apart from my rebuild project, the last bungees I replaced on one of these three was in 2001, and this particular aeroplane has done about 1500 hours since then).

As a matter of interest, when was the last time you heard of a properly inspected & maintained Taylorcraft having a collapsed undercarriage caused by a failed bungee?

[Hank Jarrett]

Re: Bungee Cords

Been a while but I helped lift a tandem back up so a rope could be tied in place to hold the gear. You guessed it, the cable was routed wrong and didn't hold when the bungee failed. Wrecked both struts on one side and damaged the tip and aileron. Got some nice damage to the gear and nose too. Couldn't see if there was damage to the gear attach. The plane was owned by an A&P and well maintained but the bungee failed anyway. Didn't hear what caused the bungee failure but it sure caught us off guard that the cable wasn't in the right place.
Hank

Don't fly without the cable. Don't taxi either!

[Karl Rigdon]

Re: Bungee Cords

35 years ago my IA told me to select the best of the old cords and install one each side on top the 2 new cords. This has worked great for me. I seem to remember Forest has stopped using the 1010 paired with the stock cord. I think he suspected unequal load sharing. I will welcome coments from Forest on this if I do not have the correct memory on this subject.

[Laz]

Re: Bungee Cords

This is a subject near and dear to my heart. I took my flight check for my flight instructors rating in 1971 at price field , Columbus Ohio. The FAA inspector sat through a two turn spin ( in those days you did have to demonstrate spin recovery) after that all he asked me to do was a full stall landing on a particular spot on the runway. The landing went great, right on the spot, then the right cords left go. The safety cable did its job and the T-craft suffered no damage. After tying up the right gear with rope I received my flight instructor certificate. I restored that airplane in 1970 the shock cords were less than a year old. If there had been no cables I would have been in big trouble, and so would the IA who signed off my work. A violation on my record, no aviation career.

Don’t go with out them. They were put there for a reason.

I plan to cover the safety cable with shrink tubing. That should help.

[Pearson]

Re: Bungee Cords

I thought about the heat shrink tubing on the cables the last time I replaced them. But it is like you say Mark, you have to put it on when you are installing the safety cables. I will try putting some tape around them to see if that will help the cords last longer. Thanks for the input everyone.

[Guest]

Re: Bungee Cords

Get a length of clear vinyl tubing with a 3/16" or 1/4" ID from your local hardware store.

Slit open the side wall for it entire length with a sheetrock knife. Do not cut it in a perfectly straight line. In fact cut it on a spriral like a flute on a drill bit or barber pole, this helps it stay on.

Slide the tube over the already installed snare cable. Put a short piece of tape every 3-4 inchs as precaution of it coming off just in case.

Dave

[Ragwing nut]

Re: Bungee Cords

Saftey cables should not interfere with the chords if placed in the correct position. I put them to the inside and then tie wrap them where they won't rub the chords. I have never had a chord failure due to cables cutting them.

[Guest]

Re: Bungee Cords

I think that Mike is right.

I too have never had a bungee fail due to a snare cable or safety wire that was properly installed. Although I do sill suggest the wrapping method I mentioned above for antichafe of fixed cables, controls and tubes. I have used it many times and I am very happy with it.

However I have had bungees fail because my gas tank was over filled or leaked so much that the gas dripped down the planes bottom and effected them.

Also I had them fail because of improper installed safety wire that cut thru them (my fault)


Dave