[CharlieWaffles]

I am working on laying out my control panel. I have sizes for items like the Garmin GTN 750 (6.25" x 6") and for the PS-Engineer PAR 100EX (6.25" x 1.3"). What I am not entirely clear is how is the standard/usual radio mount connected? That is to say, is the panel cut smaller so the mounting rack for these devices slide in from the front and the device that goes inside is slightly smaller than the rack? Or do you cut your hole to the size (as above for instance) and the mounting rack is just aligned BEHIND the hole and the units are the same size as the hole?

I know this is different things like EFISes, but I am specifically wondering about these two devices.

 

[krwalsh]

Add 50-80 thou

We waterjet cut our (non-RV) aluminum panel. For all of the radio stack we cut the width to 6.330. This gives us 40 thou per side, or 80 thou total for clearance. The cages generally do not fit through this on the front, so it all goes in from the back. The units themselves will slide through the gap easily.

 

[704CH]

Just my 2 cents.. I would wait until you have the trays before you cut the panel. Sure do your layout etc, but before cutting I would have trays in hand. I am looking at my GTN 650 tray and the cut out will need to allow the bottom of the tray to slide through the panel, where the sides and top will remain behind the panel. Tolerances are pretty tight by looking at the faceplate to the tray, So I will be measuring and cut specifically to fit the tray..

Thanks

 

[az_gila]

The installation manual for your avionics should give you exact numbers.

As an example, the Garmin 400 series calls for a 6.32 and the King KY96/97 series also calls for a 6.320 dimension. Both are for front installation of the trays.

The numbers do alter if you install the trays behind the panel, but I think it may be easier to arrange it so the trays are flush with the front of your panel. A dry stack of all of your avionics will sort this out, especially if you are mixing brands.

 

[Flying Scotsman]

On the other hand ...

I had my radio stack cutout sized so that the racks were installed from the back, and the radios (GMA340, GNS430W, SL40) slide in from the front. This changes the cutout size, but every installation manual IIRC had a mechanical drawing showing the sizes.

E.g., the GMA340 manual I'm looking at right now shows 3 options:
Stack cutout (rack installed from front) 6.30"
Radio cutout (rack installed from front) 6.30"
Radio cutout (rack installed from back) 6.18"

The racks are all mounted behind the panel, and the radios slide in with just a hairs-breadth of clearance all around them, making a nice, clean-looking installation. The racks are not visible from the cockpit.

One piece of advice...I spent what seemed like a huge amount of time building up the racks and making angles to hold them and all in such a way that the faceplates of all the radios are flush to each other. It was not straightforward because, of course, each one has a faceplate that has a different *depth*. Sigh. You'd think they'd be standardized, "But, NOOOOOOOOO!"

 

[rleffler]

Mark,

Like Gil mentioned, the installation manuals will supply the details. The Garmin manual even tells you the amount of gap the you need to allow for between devices. When you get the trays, you'll find dimples on the trays that force proper spacing.

Like others have said, I would wait until you have trays in hand. Most vendors will sell you trays in advance so you don't have the avionics sitting on the shelf for a long time. At least I know that Aerotronics, Stein, and Stark will.

If you need the Garmin manual, drop me an email.

Bob

 

[az_gila]

Mark,

Like Gil mentioned, the installation manuals will supply the details. The Garmin manual even tells you the amount of gap the you need to allow for between devices. When you get the trays, you'll find dimples on the trays that force proper spacing.

....
Bob

Yes... but don't rely on the dimples for vertical spacing if you are mixing vendors... again, no standards seem to exist....

I would still reccommend a "dry stack" before the trays are finally located, not only for fore/aft radio location but also for vertical spacing...

 

[Rupester]

My experience ...

...was identical to Flying Scotsman's. Even though all my radio stack components are Garmins, the setback req'd to make the faceplates line up all differ slightly. I FULLY agree with those who said to delay your panel cutting until you have the avionics racks in hand. Once you have the racks, the remaining decisions and handwork are straightforward.