Overhauling Control Cables
Wed Dec 30, 2009 7:22 am
We're soon to start on the wings of our Fiat. As part of the preparation we're stripping out all the internal gubbins for overhaul alongside the structural work we'll be doing on the wing.
One thing we need to look at is the overhaul of the control cables. Initial inspection indicates they're in great shape. In an ideal world of course they'd be replaced, but they simply aren't available. However, they are heavily over engineered and have had very little use so should be fine. They're caked in grease and dust which needs to be removed prior to a detailed inspection. We're fully aware of the need to avoid dirt from penetrating the core of the cable and would welcome input and comments from anyone who has previous experience of achieving good results overhauling control cables. Any ideas of the best way to clean and then protect the cables would be very welcome.
Thanks,
George
One thing we need to look at is the overhaul of the control cables. Initial inspection indicates they're in great shape. In an ideal world of course they'd be replaced, but they simply aren't available. However, they are heavily over engineered and have had very little use so should be fine. They're caked in grease and dust which needs to be removed prior to a detailed inspection. We're fully aware of the need to avoid dirt from penetrating the core of the cable and would welcome input and comments from anyone who has previous experience of achieving good results overhauling control cables. Any ideas of the best way to clean and then protect the cables would be very welcome.
Thanks,
George
Re: Overhauling Control Cables
Wed Dec 30, 2009 10:23 am
In the olden days 
I used to soak a rag in white spirit and wipe the cables clean. This would have a dual purpose of hopefully snagging any broken strands on the rag rather tearing into your hand, as well as cleaning. I would also note where the cable passes through any pulleys and/or fairleads and bend the cable to see if any strands stick out. Once the cable is nice and clean and pleasing to the eye, we would then soak it in Boeshield, either in a trough we had in the cable shop or a plastic bag if out in the field. The cable assembly would be rolled up and the excess Boeshield allowed to drain before fitting to the areoplane. Boeshield is good stuff, in that it will penetrate into the core of the cable, but dries off externally to a waxy finish to protect the cable.
I used to soak a rag in white spirit and wipe the cables clean. This would have a dual purpose of hopefully snagging any broken strands on the rag rather tearing into your hand, as well as cleaning. I would also note where the cable passes through any pulleys and/or fairleads and bend the cable to see if any strands stick out. Once the cable is nice and clean and pleasing to the eye, we would then soak it in Boeshield, either in a trough we had in the cable shop or a plastic bag if out in the field. The cable assembly would be rolled up and the excess Boeshield allowed to drain before fitting to the areoplane. Boeshield is good stuff, in that it will penetrate into the core of the cable, but dries off externally to a waxy finish to protect the cable.
Re: Overhauling Control Cables
Wed Dec 30, 2009 11:09 am
one additional step is to "untwist" the cable in various spots to check the inner strands and look for corrosion.
Re: Overhauling Control Cables
Wed Dec 30, 2009 11:17 am
chippie51 wrote: In an ideal world of course they'd be replaced, but they simply aren't available.
Can't you just make new ones?
Re: Overhauling Control Cables
Wed Dec 30, 2009 2:54 pm
They're metric cable and end fittings of a type which are proving somewhat difficult to track down replacements for. The cables were changed just before the aeroplane was retired so have little use, so I'd rather not throw them away if they can pass inspection. If they don't pass, it will of course be a different matter.
George
George
Re: Overhauling Control Cables
Thu Dec 31, 2009 1:24 am
Recommended for all control cables. It is what I use!
http://www.aircraftspruce.com/catalog/appages/paralketone.php
http://www.aircraftspruce.com/catalog/appages/paralketone.php
Re: Overhauling Control Cables
Thu Dec 31, 2009 5:33 am
How about a picture of said Fiat?
Re: Overhauling Control Cables
Fri Jan 01, 2010 11:56 am
Metric cables can be had but are pricey. I tried to buy some from an outfit in New Jersey but it seems they did not want my business because I wasn't going to place a large order with them.
I do a lot of work with Blanik gliders. On the L-23 and L-13, we've found that the rudder and elevator cables don't last their advertised life because the manufacturer wants them so tight (about a 1/4" cable at over 100 psi!) and they are made poorly. We looked into replacing them with US cables but the problem was with the end fittings which are metric. The aircraft can be modified to accept US fittings but again you're looking at a substantial cost. Additionally I have to keep these aircraft with a standard airworthiness certificate so any part replacement will have to be on a field approval or PMA.
Blanik charges an arm and a leg for these cables but in the end it might be worth it just to stay with the originals.
I do a lot of work with Blanik gliders. On the L-23 and L-13, we've found that the rudder and elevator cables don't last their advertised life because the manufacturer wants them so tight (about a 1/4" cable at over 100 psi!) and they are made poorly. We looked into replacing them with US cables but the problem was with the end fittings which are metric. The aircraft can be modified to accept US fittings but again you're looking at a substantial cost. Additionally I have to keep these aircraft with a standard airworthiness certificate so any part replacement will have to be on a field approval or PMA.
Blanik charges an arm and a leg for these cables but in the end it might be worth it just to stay with the originals.