Vernier cable heads up

I have the standard Van's prop control cable (made by ACS products, Lake Havasu city AZ). I found the following during the annual conditional inspection:




While the cable continues to function like this, the possibility of the cable buckling upon advancement is certainly there. I noticed this same condition on an RV4 several years ago, so it is not a freak failure. The tube is supposed to be captured loosely in the swage, so that it can move through small angles, sort of like a ball joint. It appears its only function is to prevent buckling of the cable during advancement. In any case, it is something to watch for.

I may slide a piece of silicone tubing over this joint as a preventative measure, clamping on both ends for my throttle and mixture controls. This silicone tube would prevent the metal tube shown in the picture from being able to slide apart.

Good catch

Thanks Alex,

As you siad the flex tubing should take over the "ball joint" function. Wonder if it might be worth adding a turn of safety to make sure the tube grips both ends?

Frank

Some cables...

...have a little rubber cup over this joint.... do the ACS ones come "naked"?

It is better for cable life if crud does not enter the cable housing at this point...

az_gila said:

...have a little rubber cup over this joint.... do the ACS ones come "naked"?

It is better for cable life if crud does not enter the cable housing at this point...

Click to expand...

All the ACS cables I have seen have a rubber seal at that location and a seal on the moving portion of the cable.

Yes, they have a little boot at that end, but it doesn't help retain said tube, nor does it serve any sealing purpose at all. It snaps (poorly, btw) over the swage portion, and simply slides on the tube. Not real sure just what purpose the boot serves.

I have not seen any sort of seal on the moving portion of the cable as Scott suggests, and I have three ACS cables.

frankh said:

Thanks Alex,

As you siad the flex tubing should take over the "ball joint" function. Wonder if it might be worth adding a turn of safety to make sure the tube grips both ends?

Frank

Click to expand...

Frank, I was thinking a small tubing clamp would work, or probably just a tie wrap or two on each end.

AlexPeterson said:

I have not seen any sort of seal on the moving portion of the cable as Scott suggests, and I have three ACS cables.

Click to expand...

I have a new (actually about four years old, but un-used) one out in the garage, and it "does" have the rubber boot.........as I just inspected it.

However, I know that some in aircraft will eventually wear, and fall off.

L.Adamson