Radios mounted
Monday, October 9th, 2006After a long weekend, I have the radios mounted in the panel and most of the wiring for them routed. For mounting the trays, I got all the equipment stacked up exactly where I wanted it (with the radios in the trays) and marked the outside edges for insertion depth and height position. Then I removed each radio, one at a time starting at the top, and marked the holes to drill in the side angle with a pen very carefully. I then removed both side angles and drilled them on the drill press and reinstalled them on the panel. I secured the tray and reinstalled the radio and realigned the rest of the radios and repeated the whole process on the next one down until they were all screwed in. This iterative process took me about four hours. I spent quite a bit of time working out the tray differences between the SL40 and the GNS430. The locking cam that holds the 430 in was severely hitting the SL40 tray below. This clearly had to be resolved. I decided to add some dimpled “feet” to the front bottom of the 430 tray that would match the little dimples in the top of the SL40. This added just the right amount of separation. I also used some washers on the sides of the SL40.
The cutout in the panel that I got from Fabian at Affordable Panels is about 3/16-7/32″ too tall. It sure would have been better to be a little short instead. Oh well, I made it work and am plenty happy with it. I put most of the gap at the bottom with about 1/16″ at the top. Also, I had him pre-punch the rivet holes for the support angles on the sides of the radio stack for 3/4″ angle. If I had it to do over, I would have had those holes punched for 1″ angle. The reason is that if you want to mount the radios further back in the panel, you need the extra depth of the larger angle for the mounting screws (they would be further aft). With the 3/4″ angle, you don’t have the option to recess the radio bezels very much and they stick out of the panel about 5/8+”. This is really nothing new, except to us newbies :).
With the physical mounting done I started looking at the radio wiring. I’m very glad that I had Stark build wiring harnesses for the radios but would have definitely had him do the one for the audio panel as well if I had a little more forethought. As it is, I got all of the radio equipment from Stark and ordered the audio panel (PMA8000B) from Stein. That was kind of stupid in hindsight since Stark could have pre-wired the audio panel with the outputs from the radios. It is really no big deal in the end but is a good example of how the search for a couple of dollars less on equipment can end up not being worth it.
Next up was to set the panel with the trays and wiring harnesses in the fuselage and start working out routing and wiring it all up. This is a big leap in the amount of wiring that is going on behind the subpanel. Actually, the integration of the radio wiring into everything else that I have already done was fun. I think I’m getting close to starting to verify and test a bunch of the wiring. I added all of the audio inputs from the radios to the audio panel connector.
(UPDATE: Later I found that these resistors had already been installed inside the connector shells on the radios by Stark. Very nice. So I cut out my additional resistors.) Lastly, I worked out just how I was going to package the nav annunciator excitation circuits (per the GRT wiring diagram with 10K ohm resistors). I inserted them into a molex micro-fit 3 connector (I have the cool expensive special crimper for these :), then soldered the end to a bit of 22ga wire and potted the assembly with “shoe goo” which is great stuff by the way.
