Panel Supports

The next step to finishing up the panel was to cut the center stack opening for the IFR GPS.  It'll be a minor miracle if all of this is accurate enough to not require some additional surgery down the road, but hopefully it'll be fairly close.  The standard cutout dimensions that Garmin provides must assume that the panel is being cut by machine, because the tolerances are miniscule. Cut just a hair off the mark and the bevel of the face plate won't cover up the cutout.  Because I'm cutting by hand, I modified the dimensions so the rack will set behind the panel face instead of inside the cutout space.  This will allow more wiggle room so the face plate will cover any less than perfect cut lines.  Now that I've experienced panel cutting, I can say for sure that it'll be worth a few bucks to have my next panel cut by CNC.

The audio panel and GPS are deep enough that the subpanel has to have a cutout as well.  I made the cut just a hair larger than the racks will require, then made an aluminum doubler to go behind the subpanel to stiffen the area up a little.

The racks need a way to attach to both the panel and the subpanel.  Because my cutouts were made by hand and not perfect, getting two pieces of angle where they needed to be so the audio panel face is square and flush was easier said than done. 

The audio panel rack has holes for two screws on each side that will attach to the angle on the panel.  There is also a single screw on each side towards the back of the rack. This rack was kind of a nightmare to fit.  I emailed the company to see if I got a bogus rack, but never heard back.  The dimensions are such that there's literally no way to set the rack against the panel and still have the audio panel itself cover up the hole. This seems to be a common theme with panels!  They essentially make the outside rack dimension the exact same dimension as the face plate of the unit.  Why they don't make the unit 1/16" bigger all the way around is beyond me.  I'll probably regret it later, but I made my cuts to ensure all of the cutouts would be hidden.  That meant making a smaller cutout and offsetting the racks behind the panel instead of thru the panel, as normal.  It makes getting everything square a lot more difficult, but worth it in the end.

Like on the panel side, I made a a couple of angle brackets for the subpanel side.  Then, measured 100x to figure out how to create angle brackets that go from the panel to subpanel.  These brackets have to set at a slight angle to capture one of the rack's front screws, then the back screw, then the subpanel bracket, so it took a bit of experimenting to get them right.  The GPS rack is larger and will also need some sort of support, but until I have the actual rack, it's just too hard to fabricate anything ahead of time.  I'll just have to suck it up and deal with the pain down the road when I add the GPS.

I pulled out the center stack to give myself a little more room to work on other panel related stuff.  Next up is finding a home for the com transceiver, fuse block and backup battery for the PFD/MFD.  I was initially going to put the com transceiver on the subpanel, but they've changed models since I first laid everything out.  The newer transceiver is not as deep, but it's taller and wider.  It just doesn't fit very well on the subpanel.  So instead, I'm putting the fuse block on the subpanel.  Here you can see it next to the big subpanel cutout.

Since the transceiver lost its home on the subpanel, I need to make a tray of some sort to mount it and the battery in between the panel and subpanel.  I screwed a couple of pieces of angle to the bottom of the panel/subpanel.  I've got some spare 1/16" sheet that I'll rivet to these to make a tray to hold the transceiver and battery.  The transceiver is just shallow enough that it can set on the tray without interfering with the back side of the MFD.