Control cable quandry
I worked further on the throttle quadrant control cables, the time hooking up the mixture cable. Again, I wasn’t able to get the full swing out of the mixture arm. No matter how I adjusted things, it just wasn’t working. And then it dawned on me what the problem was. The bulkhead nuts are not located in the same position relative to the end of the cable as the standard Vans cables. In the picture, the top cable is the end of Vans standard push/pull knob cable. The bottom cable is the standard Spruce A-1550.
When I figured that out, I was at first furious and then frustrated. I tried to think of how I can remedy the problem. I could fabricate new brackets for all the cables. But that would be a huge hassle, especially for the prop governor. The Aircraft Spruce catalog doesn’t mention this dimension anywhere. There are some mentions of the “travel” for a control cable, but now how that affects the bulkhead nut placement. I figured more travel was a good thing, but not in this case. It puts the bulkhead nuts further back on the cable. In the end I decided to just order new cables. They’re not cheap at $50 each, but I’d rather get them right as controlling the throttle, mixture, and prop pitch are kinda important. My main concern is that Spruce took 2 months to make them last time. Hopefully I can get that expedited somehow.
I wasn’t feeling much like working on the plane at this point. I looked around for the Pmag manual, but couldn’t find it in the usual piles. I decided to clean up the paperwork. Every little part for the plane comes with it’s own instruction manual. I grabbed a big 3-ring binder, a 3-hole punch, and some plastic Postit tabs and got it all organized by major category. Much better.
I eventually found the Pmag manual in the electrical pile and started figuring out how to wire up the spark plugs. Aircraft engines have two spark plugs for each cylinder. I know each cylinder should be fired by two separate sources, but I wasn’t sure if there was a standard approach to that. I asked the Lycoming Yahoo group.