Pushrods: Sullivan "Golden Cables"

This latest winter project called for a micro pull-pull system, but I was seeing to many possible failure points with that stuff, plus my big club mits were having a hard time hanging onto that stuff. Some small turnbuckles would have been needed to get a even pull on both cables,,then you start putting to much pressure on hinge points and bell cranks, overall weight goes up slightly, ect.

Fitted a .047 rod and tube setup, but the runs from where the guide tube ended in the fuelage to where the rod attached to the bellcrank were to long,,to much easy deflection on the length of rod hangin out.

Settled on a .062 rod and tube setup, feeling much better about that at this point. still flexible enough to curl around slight corners and it can be used on all servo control points. Slightly less overall weight than the pull-pull system once it was all piled on the digital scale,, amazingly. I thought it would be a brick control system setup with the rod and tube, but it's not bad.

It might still turn into a brick,,who knows at this point. lol.

To prevent Golden Cable deflection in my Dumas "Lil Swamp Buggy" I installed (with CA) series of small nylon electical wire holders along the route of the cable casing which has cured any problems with cable deflection.

Got the small nylon electrical wire holders at Ace Hardware.

SuperDave wrote:
Thinking of using the smallest Sullivan Golden Cables in my upcoming Guillows Spit' coming under contruction after Santa's sleigh arrives at our house.

Interestingly, that discussion came up this week in RCU: http://www.rcuniverse.com/forum/m_10814143/tm.htm

I use a lot of the .032 cable, particularly where it may need to wind around a bit. One of the real advantages of sheathed rods is that only the endpoints need to be secured tightly. I've used the Sullivan S507 sheathing for throttle linkages on planes in the .40 - .50 size, but substituted .032 music wire in place of the cable. The music wire will work where you have an extended unsupported length and carb throttles should have little if any resistance to movement.

For fairly straight runs in smaller planes, I also use .032 music wire in a sheath for control rods. However, the unsupported ends can be problematic if too long. Carbon fiber to the rescue. I've become quite an admirer of small diameter thin wall carbon fiber tubing. It's very stiff, very light and easy to work with. If I have a straight run, I use CF tube and just terminate the ends.

Most of our sport planes don't fly fast enough to produce much resistance to control deflection and usually are not prone to flutter, so pushrods can be lightweight. In all likelihood, most of the resistance is due simply to poor hinging and control binding.

The attached pic shows a short piece of solid CF rod in use -- it wasn't really needed, but I was just fooling around and trying different things. The wire used was .047, but the elevator was 14" x 2", so I moved up from .032. It also shows one on my favorite pushrod retainers on the control horn: wire insulation.

The CF rod is really easy stuff to work with, used that in the past for my foamies.

Went to a swap meet and found a guy selling out all his stock of CF rod and stick, bought it all, took home the box as well. Couldn't pass it up type of deal.

PV:

Somehow I seem to have an awfully lot of friends that have either died or gotten out of the hobby and I've been given BOXES of modeling stuff for FREE. (In fact all but two of my nineteen Coxes came to me in that manner)

But where to put in all in my 10' X 10' "shop/den"! In time I sort through what I have accumulated keeping what I want and trading off the remainder. As long as I can keep this system going I will.

But I am mindful that someday I may get out of the hobby or die too. My g'sons are the next in line as receipients.

Cool and feel free to do some trades on here!