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Aileron Cable - is this Okay?

Steve Pierce said:
500 hours on stainless aileron cables, they start fraying at the first fairlead on the lift strut out of the fuselage. Had no issues with galvanized.
Click to expand...
Does it matter what material this fairlead is made from? Would it make a difference if it was wood, phenolic, teflon or some other material? Perhaps we should consider changing the materiel that this fairlead is made from?
Stainless cable is susceptible to chafing and wear in places where we may not expect. Places such as that pulley inside the wing where the cable turns 90 degrees going to the aileron. That pulley bracket is made in a manner so the cable rubs on the side of the pulley, not good. The bracket does in many cases need adjustment.
 
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skywagon8a said:
Does it matter what material this fairlead is made from? Would it make a difference if it was wood, phenolic, teflon or some other material? Perhaps we should consider changing the materiel that this fairlead is made from?
Stainless cable is susceptible to chafing and wear in places where we may not expect. Places such as that pulley inside the wing where the cable turns 90 degrees going to the aileron. That pulley bracket is made in a manner so the cable rubs on the side of the pulley, not good. The bracket does in many cases need adjustment.
Click to expand...

It is the original nylon or whatever Piper used. Not an issue on galvanized. Have not seen any issues at the pulleys except the front elevator pulley that turns 180 degrees. Also have found frays on the rudder cables where they exit the fabric. What is interesting is that the issues I have found are on Cub Crafters data plate Cubs with 500-1000 hours. Haven't found issues on factory cables with at least 1500 hours other than the noted stainless aileron cables. Also no issues on my 13,000 hour Super Cub which I think got new cables at rebuild in 1992 but don't remember the hours.
 
I run galvanized cables on my AgCat, 1200 hrs on the current set and look fine. My buddy runs stainless on his and replace them every year/600 hrs with flat spots and fraying already starting. I’m not convinced stainless is the solution to corrosion issues on airplanes, for cables or panels. It just seems too brittle to hold up to the shaking. I prefer galvanized cables and a properly prepped and painted aluminum panel.
 
Can't believe I did not contribute here. I see 6000 hour Cub galvanized cables. Just saw both rudder cables replaced after 600 hours on a Super Cub. stainless. But worse - the restorer put aluminum cable feed-throughs in the fabric. Cut both sides almost in half.

I replaced my personal Cub aileron cables three years ago, after 5000 hours. One strand on each side broke, and was a potential hazard mostly to my fingers when wiping down the struts.

I keep oil on the pulleys and Par-Al-Ketone on the cables (sometimes).
 
My RANS S-7S uses cable for the rudder, and they travel thru nylon guides. I had both start to fray at 1200 hours (stainless) and replaced them with galvy. One thing stainless is preferable for: a hang glider or ultralight, where you are constantly handling the cables when breaking it down, your hands and the sail stays clean. For conventional aircraft use it seems to offer more disadvantages then it's worth?
 
Did you pull the fabric off to change the cables ?




fancypants said:
Your cables look pretty tight. Took me a while to find a halfway decent photo, but this shows the "slop". Feels ok to me, but it is a little strange to see the cables flapping in the wind.

View attachment 19725

I'm in the middle of replacing my cables right now, partly due to excessive slop, but mostly because the balance cable was OLD, and there was obvious wear on all four cables. I found it interesting that the cables I removed measured out almost exactly to the original Piper spec, 173-11/16" for the upper control horn cable (attaches to bottom of stick) and 167-15/16" for the lower control horn cable (balance cable above your head). So, no apparent cable stretch. The slop in the system seems to have been caused by worn pulleys and a bent pulley cage. Some of the slop could have been removed if I bottomed out the turnbuckles, but I'll feel better with new cables. We will see if the new Dakota Cub ball bearing pulleys allow cable tension to be increased without inducing too much drag.

View attachment 19726View attachment 19727
Click to expand...
 
C-FIJK said:
Did you pull the fabric off to change the cables ?
Click to expand...

Why would you need to remove fabric??

Cut, heat shrink new cable to old, pull it in gently.

If you are good you get it all cut to proper length before pulling in the final piece .....

If you are not gentle you break the heat shrink or pull it off cable and your life gets sad fast....


Sent from my iPhone using SuperCub.Org mobile app
 
Gerry,

I did not remove any fabric to replace my aileron cables. As Mike mentions above, it's possible to feed the new uncrimped cable into place without major disassembly.

That said, if I were to do it over again I might just buy the pre-fabricated cables from Univair. Since I was replacing all of the pulleys at the same time, my recollection is that it would not have been much more trouble to snake the finished cables through the wings. That was a while back, so I might be forgetting something.
 
If you are worried about heat shrink failing to keep the old an new cable ends together while pulling through the airframe (especially with the cheap Chinese heat shrink found at your corner auto parts store) you can take some 20 thousandths safety wire and spiral it down each cable across the splice area and then cover both it and the splice with heat shrink. The wire will aid the heat shrink's tensile strength. Or go liberal on the heat shrink length by using a good 6 to 12 inches of it to grip more cable on each side of the temporary splice. There is also some good thick adhesive-lined heat shrink but it might be too stiff to bend well around pulleys. Try to use 3:1 or 4:1 ratio shrink tubing to grip the cables with more pressure.
 
Mike so what you are saying is , cut the cable to length put a eye in one end , feed the other end through the wing and when it comes out have the cable marked so you know where to put the eye on the dead end ?
 
C-FIJK said:
Mike so what you are saying is , cut the cable to length put a eye in one end , feed the other end through the wing and when it comes out have the cable marked so you know where to put the eye on the dead end ?
Click to expand...

No

Cut end off original cable, splice on new cable or a scrap. Pull out old cable. Make a new one using the one you removed for length. Do not crimp 2nd end. Now splice this new one on and pull it back in.


Sent from my iPhone using SuperCub.Org mobile app
 
Hey Gerry
To do the heat shrink splice: Place a clean, cut, end of the new (or sacrificial) cable, butted up against a clean, cut end of the original cable. Slide a piece of heat shrink over this arraingement so that there is about 3 to 4 inches (or a bit more, if you prefer) of heat shrink on each side of the butt ends. I prefer the heat shrink with adhesive on the inner walls for this. Heat the shrink thoroughly to reduce the size and make the glue flow, then let it cool for a couple of minutes. Now GENTLY pull the orhenginal cable out while a helper feeds the new cable in. Be careful when pulling the splice around pulleys and through fairleads. Once the new cable is in place, crimp on the appropriate ends. It's not difficult. Up here, the only time people cut fabric for new cables is when bad things have already happened.

Web
 
mike mcs repair said:
Why would you need to remove fabric??

Cut, heat shrink new cable to old, pull it in gently.

If you are good you get it all cut to proper length before pulling in the final piece .....

If you are not gentle you break the heat shrink or pull it off cable and your life gets sad fast....


Sent from my iPhone using SuperCub.Org mobile app
Click to expand...

Fun fact on the early carbon cubs and sport cubs the balance cable is one piece and goes through the flap torque tube. That’s a fun one to replace. They got smart on the later carbon cubs and had a connection in the left wing a couple ribs out.


Sent from my iPhone using Tapatalk
 
fancypants said:
Gerry,

I did not remove any fabric to replace my aileron cables. As Mike mentions above, it's possible to feed the new uncrimped cable into place without major disassembly.

That said, if I were to do it over again I might just buy the pre-fabricated cables from Univair. Since I was replacing all of the pulleys at the same time, my recollection is that it would not have been much more trouble to snake the finished cables through the wings. That was a while back, so I might be forgetting something.
Click to expand...

If the pulleys are out you can fish a spliced cable through. I was told Univair tests all there cables as well.


Sent from my iPhone using Tapatalk
 
Yep, not really possible to pull test cables if you fabricate in place. I think when I added it all up with the cost of the special piper forks, cable, thimbles, and nicopress sleeves it was pretty close to the cost of the fabricated Univair cables.

If you do decide to make them yourself, be sure to check your crimps with a go/no-go gauge or micrometer. I don't have the measurements handy, but they should be easy to find. Let me know if you need to borrow a crimper, I ended up with a couple surplus ones off of ebay.
 
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