New Control Cables
Installed 7/11/2012Recently while on my Alaska trip and before, I've noticed my Mixture and Throttle cables becoming a little "clicky". They were a little more stiff than when new, but they had kind of a feeling of hitting small detents...a ratcheting feel, while moving forward and aft. It's hard to describe, but instead of a totally smooth feel, they felt like they would be rubbing over something bumpy as they moved. The interesting thing is that on one of my earliest flights, I had noticed the green outer plastic sleeve melting and drooping a little on the prop governor cable. I wrapped it in aluminum tape to provide a heat reflective shell, and after that, it was never a problem again. But it was the OTHER 2 cables that were the weird feeling ones now. So, I decided that it was time to get some new, smooth cables, before OSH, since I may be flying some formation with people and I wanted everything to be perfect.
A couple other RV-10 builders had a while back located a good source for Cablecraft cables, http://www.push-pull.com/, that also came with a slightly higher temp outer sheath. A great guy named David did my order (530-893-4060). I should add that even if you have the standard green cables, you're probably JUST FINE, as long as you take some extra precautions, and if I knew then what I know now, I'd have probably just kept Van's cables, but installed some 1/2" orange hose firesleeve over them wherever they were near heat, and then wrap that firesleeve in aluminum tape. Doing that, you will likely never have a problem. But for me, it was too late, so I ordered new cables and may as well get the black ones.
My original cables were:
Throttle 45.5"
Mixture 49.5"
Prop 70.5"
2-1/16 to 2-1/8" throw
.340 diameter approx.
When I ordered my new cables, I was really concerned about the amount of throw. I know that 2" is the standard throw, but mine were 2-1/16 to 2-1/8" or so, and I had my quadrant PERFECT, so that the cables moved stop to stop and also were stop to stop on the quandrant end, giving absolutely 100% control over the governor, throttle, and mixture. David let me know that 2" is the ordered throw distance but they always shoot for 2" minimum, so yes, they usually end up just a little over. So I went with them. That's the one thing I wish I had changed now....I wish I had ordered 2.25" throw instead.
The parts I ordered were:
176-VTT-2-45.5
176-VTT-2-70.5
176-VTT-2-49.5
That's type 176 cable, with threaded ends, 2" throw, and the standard length. Despite some other builders having different distance requirements, I find that Van's cable lengths are right on for what I need (I have a quadrant), and any shorter or longer wouldn't be correct. When my cables were delivered, they had almost exactly 2" or 2-1/16" throw, but the mixture was right at 2". This turned out to be just the smallest amount imperfect. I can still get the throttle to go stop to stop, and the same with the prop. The mixture, however, goes to full rich, but on the lean side, I'm short of the stop by maybe the thickness of 2 or 3 sheets of paper. The engine quits fully when leaned well before I hit the stop, but I would prefer to have more throw than 2", so I would recommend that if you do order cables, go for an extra .25" of throw...you may want it.
Additionally, when I ordered the cables, I told them of my intention to heat shield them. They said that indeed, that ratcheting feeling I had was indicative of internal heating and the start of the nylon inside failing a little. No, I wasn't near having some catastrophic event...but they weren't going to get better on their own...and no, you don't lube the cables, so they weren't just dry. Dave told me of some silver wrap that they sell...it's not exactly like our fire sleeve, but is what racers use, he told me. It's a fiberglass tube with silver over it. I ordered 2 sections of 3' each, and installed that on the cables. I think I would have preferred my 1/2" hose sleeve with aluminum tape, as it would have stayed nice and round, but this stuff flattens out nice and I kind of folded over the excess and wrapped it with aluminum tape too. So in the end, my cables are now all heat shielded, replaced, and they are once again super duper smooth! BTW, the cost per cable was under $60, so it isn't a fortune to replace them all....but it is a bit of a pain!
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