Rudder Cables & warning

[N2540V]

Cable Maintenance
Cables are manufactured with grease on each strand. When the cables go around a pulley, the strands move at different rates and slide against each other.

When solvent, Corrosion Inhibiting Compound (CIC) and other materials are on a cable, it wicks the lubricant (grease) out from between the strands and now you have fretting of strand against strand with every cable movement. This is less important on straight-a-ways.

Cables should be maintained with wiping grease on the outside of the cables. Solvents and other contaminents should be avoided.

Stainless Steel vs Carbon Steel.
In a dry environment, the carbon steel cable is more flexable and will last longer than the stainless steel.

To put it in perspective, a big bird is not a small 170. But I have written in the cable manuals for the big birds that contamination of the cable with solvent, CIC’s, paint, etc, the cable is discarded. That really ticks the factory off when they forget to mask the cables before spraying.

Jim

[N1478D]

GEE! I've been spraying Corrosion X at annuals thinking that I was helping. That's valuable information Jim, Thanks. Wonder if when the professionals (or FBO's) perform a corrosive protection process if they protect the cables? Does the wiping grease have a name, brand, etc to look for? What's best to do with the pullys, should we not spray those either?

And Jim(Metal Master) thanks for the outline on cable examination, I have printed that for reference. It's great that you guys have taken the time to share information, THANKS.

[william halford]

Jim , is correct on what he says about cable lubeing, My partner works for a major airline, We clean and service our cables just like you would do a DC-10 our AIRBUS. Every Annual we wipe the cbles down ( clean rag with no cleaner of any sort on it ) ck them , he takes a regular cotton screw bag fills it half full of grease and lightly coats the cable by folding the bag around the cables the graese will seep thru the cotton bag. He told me that Boeing does not recomend lubeing any S/S cables.

It is a long drawn out process but it is well worth it .
My suggestion is one year do the Wing cables, the next year do the Fuselage cables, then rotate back to the wings..

This also will satisfy the FAA ageing aircraft inspection.. bill

[N2540V]

When I said “wiping grease” I meant it not as a product but as the act of taking a rag with grease on it and wiping it to deposit a light coat of grease on the cable. Please note the term “light”. Change your rag often so that any grit you pick up is not ground into the cable or deposited elsewhere.

When you lightly coat the cable, it acts as a barrier to protect the volatile portion of the original grease from evaporating from the cable itself.

It would be really nice to wipe the entire cable as it helps prevent corrosion. But I would put the most effort into cable that bends around the pulley - remember the length of cable from stop to stop.

As to what grease to use, you need a light grease that will easily spread and leave a light coat. I would suggest that you use what you use on the aircraft already.
Jim

[zero.one.victor]

Off-topic, but Jim-- how's that Avid flying? Sure looked like a fun airplane!

Eric

[GAHorn]

Cessna 100 series Service Manual, 1962 and Prior, Section 2, Lubrication, Figure 2-4. "Do not lubricate roller chains or cables except under seacoast conditions. Wipe with clean dry cloth."

(Lubricant will attract dirt/grit and will damage cables.)-gh

[c170b53]

With the hours that are put on small aircraft, its the lack of flying thats damaging the cables (corrosion).

[N2540V]

The probation on grease I have placed in the manuals for stainless steel cables is very explicit. SS cables are softer than carbon steel cables. A SS cable passing through a fairlead with grit causes the grit to abrade the SS cable significantly faster than a carbon steel cable.

In dynamic testing (running cables back and forth on pulleys and fairleads) without adding grit, the SS cables will last longer than carbon steel.

Now, back to cleaning and preserving cables. They cannot be relubricated. Once the lubricant evaporates from between the strands, it is gone forever. You want a preserving film left on the cable to retain the volatiles in the strands. More than that and you will pick up grit.

Eric.
Avid undergoing taxi testing. Chasing down electrical ghosts and noise.
Expect wife to fly her about March. I stopped working on the 170 to help finish the Avid and will resume the 170 as soon as all bugs in the Avid are taken care of.
Thanks - Jim