Firewall Forward

Now that I've made some decisions about my panel (see my Panel intro page), it's time to get busy! It really feels good to have the "homework" mostly done about my panel and electrical system, so I can start in and get to work. So yesterday, I made a trip down to Advanced Flight Systems. I had an appointment, and Rob helped me put some finishing touches on my plans and put together a list of things I'll need. I'm anxious to get started! I can't buy everything all at once, so I'm getting what I can right now. I ended up coming home with a big box of engine sensors, wiring harnesses, probes, and so on. Here's a picture of it all, laid out on my bench in my shop. This is about $1,200 worth of stuff! I might also mention, I'm not counting any of my time on my various trips to Vans or to Advanced. I'm also not counting any of my reading, study, or internet browsing time on my project. Only hours in the shop. At this point in the project, I'm spending many hours "behind the scenes" compared to earlier phases of the build.

The parts you end up with in this kit depend on your engine configuration. For example, I have one slick mag, and fuel injection. That determines the contents of this box. The three big wiring harnesses are impressive. They are custom made by Stein for Advanced. They will plug right into the AF-5600. Having these harnesses in hand will save a novice like me a ton of work. I figure half the wiring is already done for me, before I even start! Also seen above, starting in the upper left corner, some shrink tubing and crimp connectors for the Thermocouple Terminal Kit, the infamous "red cube" fuel flow transducer, then the EGT probes with yellow leads (one for each cylinder's exhaust pipe). Below that are a pair of transducers for fuel pressure and oil pressure. Next is a solid-looking black electrical shunt. Then on the lower left we have an RPM sensor that connects to the non-impulse Mag, then the OAT sensor, another connector for the magnetometer, some long CHT probes, and finally, two bags of stuff that comprise the manifold pressure sensing system. It took me a while to even figure out what all this stuff is. It ought to keep me out of trouble for a while.

Time to get busy! Uhhh... okay... what do I do first? Where are the directions? I downloaded and started reading the Advanced AF-5000 Installation Manual. Wow. This manual is 228 pages long. The first 79 pages are the Pilot's Guide. The Installation Manual starts on page 80. The Engine Sensor Installation manual for Lycoming Engines starts on page 141. (Note that this manual is frequently updated. The page numbers may change accordingly.) It would be nice to just go page by page and follow along. But I quickly learn that it isn't that simple. The first thing discussed, for example, is the installation of the CHT probes. Since I don't have my exhaust system replaced yet with the proper one that fits, I can't do that yet. I'll skip that for now.

Next item is the red RPM sensor that is installed on the Mag. I carefully read all about it so I know which vent cap to unscrew off of the mag, to replace it with the RPM sensor. When I get the cap removed, I'm shocked to see rust inside the mag. I don't know anything about mags at this point (another learning curve I'm facing) but I don't like this one bit. There's no way I'm going to look the other way and install the RPM sensor here. So a new project has just been added to my list. I have to look into this mag situation and get some advice. No RPM sensor installed today. I put the vent cap back on and moved on.

UPDATE - Sept. 27, 2013: I sent an email with this picture to Aircraft Magneto Service, and asked them about this. Apparently, to my great surprise, this is no cause for alarm. Here is their reply to me, quoted verbatim: "The surface rust you are seeing is on the magnetic material of the rotor, and is no cause for alarm. This happens when mags sit for periods of time and or high humidity environments.  You are not required to remove the mag until you reach the 500 hour mark, at that time send both your mags in for a 500 hour inspection as per Champion Aerospace Slick Service Manual F1100, L-1363E, Section 3.0 Maintenance/Section 3.3 500-Hour Inspection Aircraft Magneto Service". Well, that definitely makes me fell better about this situation! However, I'm now seriously considering two P-Mags for my ignition system, so I'm still not installing an RPM sensor in this mag, for now. If I decide to keep this mag and install a P-Mag on the other side (there's nothing there now), I can always add it later. It's a simple task, only taking a few minutes.

Well, so far, this isn't going so well. What else can I get done today, while I have some shop time and this big box of stuff? Next in the manual is the oil temperature sensor. It describes how the oil temperature sensor is mounted to the engine, usually near the oil filter adapter. Guess what... I don't have an oil filter adapter or oil filter yet for my engine. Strike three! Am I out? No, this isn't baseball. I'll keep going.

What's next? Am I going to get anything done today? After skipping past a big section in the manual dedicated to Rotax and then Jabiru engines, the next item I find is the "red cube" fuel flow transducer. I quickly learn that there is more to this than meets the eye, and I'm going to have to do some studying and learning before making any decisions about how and where to mount it.

Keep going... next in the manual is a discussion about the manifold pressure installation. I've been wondering about this one. The transducer manifold that I got from Vans and mounted on the firewall has 3 places for use. Two of them are obvious, and I already hooked up hoses from the engine... the oil pressure and the fuel pressure hoses. Vans says the 3rd one can be cut off if it isn't used, but I've noticed that some use it; some don't. How do I know whether or not I'm going to use it? I don't know at this point. More reading and studying coming up. The Advanced manual says the manifold pressure transducer can be mounted on the firewall or in the cabin area. That's it. That's all it says. So which is it, for me? Again, I don't know. And if I did, I have no idea where to place it. More reading, studying, and work coming up for the manifold pressure.

As you can see, I'm really spinning my wheels. I have apparently jumped into the middle of a set of tasks that I'm just plain not ready for yet. I did find one task, however, that I could complete today. I pulled out the bag with the CHT sensors in it and started looking through the manual. When I learned where these sensors go on each cylinder, I got down on the floor and looked up. There they were! No plugs to remove or anything. They're just ready to go! Here's what you see from down under the engine. To the left of the red exhaust cover plate is the spark plug, and behind the spark plug is the port for the EGT sensor.

Here's a closeup. Clean as a whistle in there!

Here are the CHT probes installed for cylinders #1 and #3. You can see the loose wires dangling freely for now.

And here are the probes for #2 and #4 cylinders:

I did get one more thing accomplished today. I identified and installed the transducers for the fuel pressure and the oil pressure (yes, they ARE different, even though they look the same).

I didn't torque these down. They're just finger tight for now. I figured that when I wire things, I may find it easier to be able to take them off temporarily. You can see the 3rd position on the top of the manifold for the manifold pressure hose, if it turns out to be advantageous for me to use it . We'll see. Stay tuned.

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