Over the past few work sessions I have ironed out all the little things in my electrical system that remained to be done. The big items were: the OAT sensor (outside air temperature), the ELT (emergency locator transmitter), and my comm radio and transponder antennae.
The OAT sensor had to be wired in to my computerized instrument display. It had been a while since I'd worked on electrical system stuff so I got to gauge the effectiveness of my old notes. I'd give myself a 6/10 it was workable and after some cross referencing and thinking about it I was able to reconstruct how everything had been wired but it was not as easy or clear as I thought they would be when I wrote them. I added a lot of clarification and a couple sketches to help make the next time I go poking around behind the panel a bit easier. The actual wiring job was easy enough I had to solder one side and crimp a fast on onto another wire. Then all I had to do was dive under the panel head first and route the new wires into my existing bundles.
OAT sensor
The ELT is a very important safety instrument. If I have an off feild landing the ELT will help search and rescue find me. I mounted it under the seat so that the antenna cable wouldn't have to be very long. I drilled a penetration in the belly skin and made sure the antenna got good metal to metal electrical contact with the airframe. The antenna needs a good ground connection in order to send a clear and loud signal in the event of disaster. My ELT was installed!
ELT antenna
ELT
The transponder and comm radio antenna wires had to get from behind the panel to the belly skin. The comm was going to get installed under the seat and the transponder on the belly behind the baggage compartment. The cables got routed to the passenger side wall and behind the side panels out of the way. They ducked under the seatpan and the comm went to the antenna while the transponder penetrated a few bulkheads on its way back behind the baggage compartment.
Transponder antenna
Comm antenna
Once all these electrical details were done it was time for a hot test of the electronics. I had done continuity tests to make sure everything was wired correctly. According to the previous tests, everything should have worked and my instruments should be ready for power. Nevertheless I was nervous. I took all my fuses out of the main power bus so that I could power each instrument one at a time. The first one up was my EFIS from GRT. This has all my primary flight instruments like airspeed, GPS, and altitude, and has lots of nice computer gizmos in it. It is also my most expensive instrument so if I tried it it would not be a happy day.
I turned on the battery switch on and waited for the electricity to flow. I didn't have to wait long, you know electrons move at the speed of light and all that. The relay clicked over and the EFIS screen erupted in s flash of light and then it went black again. For about 6 seconds I thought for sure I had killed my EFIS. Then it started booting up.
I went through each instrument, adding back in their fuses to complete the circuit and it everything worked perfectly except for the transponder and its encoder. Its an old analog model so there was not really any feedback when I turned it on. It didn't have any flashing lights or beeps or any way of knowing if it was working. So I'll just have to wait to test that when I can call up ATC and ask them if they see my transponder signal and altitude encoding. So for now I'll assume it either worked fine or it didn't work but I didn't see any smoke or smell any melted electronics so its not a catastrophic failure.
Here's a picture of me with all my instruments running smoothly
The next stuff I work on will be cowling related. I need to instal some southco hardware and do some more trimming and slight fitting.
Thanks to everyone who's supported my project!