This has been one of those weeks where I seemed to flail away, but not accomplish as much as I hoped. My first task of the week was to do the wiring for the Navaid wing leveler. Simple enough, except that I wanted to be able to disconnect it quickly if it does something strange. I‚'ve got a red button on the stick grip which will be the disconnect switch. To further complicate things, that red button will also disconnect the electric pitch and roll trim, just in case they ever have a run away. And to top it all off, the trims are powered from the essential bus, but the Navaid is powered from the main bus, as I am willing to do without it if I ever have an alternator failure and have to shed some power users.

So, my wiring diagram has a two pole disconnect relay, controlled by the disconnect switch on the stick. One pole of the relay controls the trim power, and the other pole controls the Navaid power. However, I had actually purchased this two pole relay. I had expected that it would be easy to find at the local electronics supply place that I frequent. Sure enough, they had a suitable relay, but this relay needed to fit into a socket, and the only sockets they had were designed to be soldered to printed circuit boards.

This set me off on a several hour search through paper and on-line catalogs. I was able to determine that NTE, the relay manufacturer, made several different kinds of sockets, and one of them was sure to be correct, but the descriptions were so cryptic that I couldn‚'t be sure which one I needed. I finally had a bright idea and searched their list of distributors, which highlighted a local distributor that I wasn‚'t aware of. A quick visit to Gervais Electronics proved fruitful, as they had exactly the relay and socket I needed.

If anyone else needs a small, low power two pole relay and socket, you might try the NTE R14-11D10-12 relay, and the NTE R95-111 socket. This photo shows the relay, socket, mounting bracket to hold the socket, and the wire that secures the relay to the socket.

Thursday I fabricated a mount to hold the relay socket, and yesterday I soldered the various wires to the socket, installed the relay and finished wiring the Navaid (except for the input from the GPS). I threw the switches, and everything worked, except the Navaid servo turned the wrong way - i.e. it moved the stick left when I commanded a right turn. This issue is covered in the Navaid manual - depending on the details of any individual installation, the servo direction may need to be reversed by switching some wires inside the servo. Today I pulled the servo cover, got out the soldering iron and swapped two pairs of wires. Now it works properly. I will have to go through a phase of setting system gains, etc, but I‚'ll sort that out once I get flying. I don‚'t plan to have the servo connected to the stick for the first flights, as that means one less failure mode to worry about.

Today I started on the pitch trim wiring. I thought I knew where I wanted to put the rear seat pitch trim switch, but I finally realized today that my originally planned location would put it too far aft, which would make it difficult to use. I studied the cockpit, and saw that the best location was just ahead of the rear seat throttle lever. There was just enough room to get a switch in there, if I could find a single pole switch. I had a double pole switch I was planning on using, but I was only going to be using one of the poles. However it was too wide to fit - I needed a single pole switch that was spring loaded each way from centre. Another big search through web catalogs and I finally found the switch I needed, and a distributor who sells it.

Many months ago I spent hours fighting with the rear seat throttle as I installed it, and I dreaded the day I would ever have to do it again. Well, I couldn't drill the hole for the rear seat trim switch without removing the rear seat throttle, so I had to pull it out today :(. It took about an hour to get it out and back in again, but it actually went much better than the first time I did it.

I also trimmed the coax cable for the transponder antenna, installed the connector and hooked it up.

And to top everything off, our main computer decided to have a hard drive problem when I attempted to download the photos I took. So no pictures tonight (pictures added on 29 Mar 03). The hard drive utility is running now, but it doesn't look good. I think I'll have to reformat the hard drive and restore everything from the backups. Oh joy.