I did a destructive test on the Control Cables that Vans sells. The way the cable is designed and captured in the Conduit Body you can not gain access to the inner cable at all without destroying the Conduit Body.
I have emailed the manufacturer directly and will report on what they have to say about lubrication but I suspect that they are permanenltly lubricated for the life of the cable.
Double check your cables where they may be exposed to severe heat, like around the exhaust. The cables are rated for a maximum of 145 deg F. It is very easy to "cook" the cable and this has been known to cause binding.
Also, you can reduce cable friction by avoiding bends where possible. Make the cables as straight as practical.
would firesleeve help these cables from the heat?
I agree with JonJay - I dissected a bad one and couldn't figure out how you'd lube it.
At 840 hours, I am on my second Throttle and Mixture cable, and have the third mixture cable standing by to go in to the game. I did a lot of research after I had the first one go bad, and came to the conclusion that FWF heat is probably the issue, and that I couldn't find a reasonably priced alternative that promised to be much better. However, hope springs eternal, and every once in awhile, I go off on an internet search for better cables....
Paul
Paul,
I am on my second Prop and Mixture cables. They were both Van's quadrant cables with "NOT FOR AIRCRAFT USE" printed on the cable itself. I have replaced them with aircraft cables from Aircraft Spruce. I wonder if the construction of the "aircraft" cables is significantly different. I have extensive heat shielding to protect the cables from the exhaust, and have wrapped several places with fire sleeve. If your internet search turns up the perfect cable for the job, please let me know.
Paul,
I am on my second Prop and Mixture cables. They were both Van's quadrant cables with "NOT FOR AIRCRAFT USE" printed on the cable itself. I have replaced them with aircraft cables from Aircraft Spruce. I wonder if the construction of the "aircraft" cables is significantly different. I have extensive heat shielding to protect the cables from the exhaust, and have wrapped several places with fire sleeve. If your internet search turns up the perfect cable for the job, please let me know.
I could be wrong (or my info outdated) Smoky, but I did some burrowing into the information, and discovered that the ACS cables were basically the same as the Van's cables - same company I think. So based on that, I just got the Van's ones again. I may try the ACS cables next time - I have the change procedure down to about two hours of labor...
I really think this is a general heat issue, and agree with the posts that fire sleeve probably won't help - I know as a long-time fireman that all the insulation in the world isn't going to stop you from reaching ambient temperatures eventually.....
Paul
Have you found the Spruce ones better / longer lived? I am assuming you used the A-920 series of cables? Any problems fitting them i.e. in different parts / fittings?I have replaced them with aircraft cables from Aircraft Spruce
Ron... Have you found the Spruce ones better / longer lived? I am assuming you used the A-920 series of cables? Any problems fitting them i.e. in different parts / fittings?
Andy & Ellie Hill
RV-8 G-HILZ
Andy,
I used the A-1550 cables which are the same as A-920 but with a 7/16 threaded bulhead fitting at each end. Spruce says they are for use in high-temperature areas such as engine compartments. They are not a direct replacement for Van's quadrant cables as the bulkhead fitting is placed further from the end of the cable sheath. I had to re-work my control brackets to make them fit. I can't say that the Spruce cables are better. Van's cables lasted about 500 hours. I only have a few hours on the Spruce cables. Ask me again in about two years!
Our throttle cable does run close to the exhaust, and now (140hrs) needs replacing. I've done some research, probably same as Paul's, so to save anyone else:Andy & Ellie Hill
- The Van's CT Q-60 is almost certainly model number 184-VTT-2-60 from Tuthill (since that model number is on the Van's cable labels)
- The 184 is one of their better specs of this type of control to a stated Temp of 310F. See Push Pull Cable Standard - Product Data sheet...
RV-8 G-HILZ
I've been able to lube these things by disconnecting the engine end, removing the rod end, and slipping a piece of rubber/tygon hose over the end and clamping it to the outer sheath. The hose should have a foot or two of length past the end of the cable, and you fill this with gear oil. Next step is to insert the air blaster nozzle from your air compressor and pump a few PSI into the whole mess as someone works the control back and forth. Eventually, you will get a few drops of oil coming out the cockpit end and you are done.
I stopped by their booth at OSH They have a new throttle cable with a vernier adjustment. I was impressed with their quality. But, at this point they only list cables for the RV-10 and RV-12 in their catalogue. I am thinking about having them make custom cables for my RV-9A. I can find the lengths from Van's catalogue. If more of us request these cables I would think they would get added to their catalogue. The risk for me is that something doesn't fit properly. I need to remove the cowling and take pictures and measurements first.
I also stopped by the McFarlane booth and was impressed by their cable knobs, especially the vernier-type throttle body. Are their cables rated to high heats? Anybody..?
My mixture control has become very stiff until the engine warms up.
I'll be pulling the cowl soon so I can disconnect the cable end from the carb, that way I can see if it's the carb arm that's stiff or the cable. But in the meantime I was wondering if anyone knows whether this kind of thing could be something like a bad o-ring or ?? in the carb?
Because most of the posts here mention sticking in spots etc. but mine is just really stiff throughout the full range, until it warms up then it's fine.
1200 hrs on the cable and carb, btw.
I removed the throttle cable on my RV-8 today. It's equipped with Titan IO-360, Bendix FI and Vetterman exhaust. Almost 700 hours TT.
The throttle quadrant was getting difficult to manipulate/actuate while the engine was cold. Once hot, not so much.
The cable crossed over two exhaust pipes on its way to the firewall. Both exhaust pipes have heat shields clamped to the pipe to shield the throttle cable from radiant heat. The throttle cable also had about 5 inches of fire sleeve over the cable in the area where it crossed the two exhaust pipes.
After removing the cable I discovered the outside green sheathing that covers the throttle cable was melted to the inside of the fire sleeve. It actually took quite a bit of force to remove the fire sleeve from the cable. I had to cut the fire sleeve length wise to get a look. The spot where it melted was directly over the area where one of the exhaust pipes crossed. The melted portion was about 2 - 1/2 inches long. The pipe closest to the FI servo was was where the melting occurred. The area where the second pipe crossed the path of the throttle cable did not exhibit any signs of melting despite the two pipes having almost identical heat shields.
I'm considering wrapping the exhaust only in the areas of where these two pipes intersect the throttle cable.
Also, if I could create a small air gap between the heat shield and the fire sleeve surrounding the throttle cable, I think that might help.
Heat rises. What if the cable was routed underneath the exhaust pipes instead of over the top? Any one ever try this?
I really like the idea of using the McFarland Aviation product.
Any one using these care to comment? Any advise/comments are appreciated.
Any
Hello Charlie,
I only have about 250 hours on the McFarlane cables since I replaced the last Vans set. The Vans lasted about 500 hours each time. I now have 1350 hours on my plane. The McFarlane cables appear to be a high quality product. However, they are 3-4 times the cost of the Vans. Even if I only got 1000 hours out of the McFarlane cables, I would still be happy since they are such a pain to replace. Good luck!
might be converting control runs to use stainless steel Bowden cables. No liners to melt/jam. Bug nuts on engine end. Cable clamps on the quadrant end.
I have no idea how much more force would be required to move the controls, maybe a bit more. A somewhat more complicated build, however.