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Avionics Placement

Av8torTom

Well Known Member
Hello again,

I'm planning out where to place all my Garmin goodies. I have 2 questions now (I'm sure I'll have a lot more later). First - as I understand it, there are 3 acceptable locations for the GMU-11 compass. Behind the bagage bulkhead on a fabricated shelf, under the tail fairings, or out in the wing. Pros and cons for each? Second - Where is the best place to put the GTX-35R transponder given it's in a tray, and removal room needs to be factored into the location.

Thanks in advance,

Tom
 
I’m in the process of a complete panel replacement/upgrade in my F1. Original panel was gen 1 Dynon and panel mounted radios. New one is latest gen Garmin 3GX with remote radios. The remote radios save a lot of panel space which I used for a 2nd display. At first I thought the remote radios would make things easier as well but that has not been the case. Finding a place to mount everything while maintaining good serviceability has been a bit of a challenge. As of now the com and transponder are going under the floor boards on either side of the front seat. Wiring runs to the displays are longer (antenna runs are very short) but this opens up a lot of space behind the panel.
 
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Serviceability is big

Finding a place to mount everything while maintaining good serviceability has been a bit of a challenge.

Your priorities are wise. I recently did some work on a particularly well-hidden piece of gear behind my panel, and found myself wishing that its installation had been better thought out.

It occurred to me, as I lay inserted in the footwell of the RV, that there are several (related) considerations: (1) you need room to get your hands in to unplug whatever needs to be unplugged, (2) the connections should be the easiest possible type to remove, (3) you need room to get tools on whatever hardware fastens the gadget in place, (4) you need to avoid covering the gadget up with other stuff (other wiring harnesses, etc.) once it's installed, and (5) you need enough slack in wires, etc., to allow for creative wiggling.

I'd love to have lunch with a grizzled mechanic and interrogate them about hints and techniques for working behind panels.
 
I?m in the process of a complete panel replacement/upgrade in my F1. Original panel was gen 1 Dynon and panel mounted radios. New one is latest gen Garmin 3GX with remote radios. The remote radios save a lot of panel space which I used for a 2nd display. At first I thought the remote radios would make things easier as well but that has not been the case. Finding a place to mount everything while maintaining good serviceability has been a bit of a challenge. As of now the com and transponder are going under the floor boards on either side of the front seat. Wiring runs to the displays are longer (antenna runs are very short) but this opens up a lot of space behind the panel.

A coupla thoughts, based on 200+ hours on a dual screen G3X touch installation. (I posted something like this recently, but can't find it. In my configuration, each screen has engine instruments on the outside, then flight instruments, then the "MFD" on the inboard part):
* I almost never use full screen displays. Occasionally, when I'm hand flying with round gauges, I'll go full screen to make the gauges bigger. That's it! As for peripheral roll cues with the full screen PFD, I find those negligible;
* With track up on the "MFD" displays, there's little if any reason to go full screen. I'm not sure that I ever have;
* All this being said, you can get almost as much functionality, single pilot, from a 10" and 7" screen as from two 10" screens. This could mean that you could panel mount some of your radios, and having dedicated knobs is much more usable than bringing up a touch screen. Voice of experience;
* Touch screens do marvelous things for access behind the panel. Four Allen head screws and one connector and you've got all kinds of access;
* Don't know if cooling would be adequate with under-floor mounted avionic or not.

YMMV,

Ed
 
All this being said, you can get almost as much functionality, single pilot, from a 10" and 7" screen as from two 10" screens. This could mean that you could panel mount some of your radios, and having dedicated knobs is much more usable than bringing up a touch screen.
Hi Ed,
Thanks for the words of wisdom. My setup is a 10? centered in the panel and a 7? portrait to the left of the 10?. I added a G5 on the right side as well. The primary reason to go with the remote radios is to save space behind the panel and make things easier to service. I was worried about tuning the radios via the touch screen but I spent hours at Sun N Fun this year playing with this and I?m pretty sure it will work for me. Hopefully I?ll have everything back together within the next couple months.
 
???

Someone must have some photos of how they installed their GTX-35R transponder in a tip-up. Anyone?

Thanks
 
Someone must have some photos of how they installed their GTX-35R transponder in a tip-up. Anyone?

Thanks
I cannot post a pic now but I do have some of an install I did last fall on a tip up 9A. I fabricated a bracket on the underneath side between the firewall and the subpanel on the passenger side. The tray was held on the underneath side by screws that went into nutplates. The brackets were layed out so the back of the instrument pointed toward the firewall. The front of the tray was angled down so that it could screw into nutplates mounted on the underneath side of the sub panel. The instrument could then be slid out toward the cockpit. This setup had the instrument basically hanging from the fabricated bracket and the sub panel in between the sub panel and the firewall. You could not see it nor was it in the way of legs when sitting in the passenger seat. It was easy to reach under the panel and release the instrument from the tray. It just slid toward you and came right out.

I will try to upload a pic when I can.
 
I couldn't figure out where I was going to put a remote mount so I went with the GTX-335. These larger remote mount units can be a challenge for sure.
 
I cannot post a pic now but I do have some of an install I did last fall on a tip up 9A. I fabricated a bracket on the underneath side between the firewall and the subpanel on the passenger side. The tray was held on the underneath side by screws that went into nutplates. The brackets were layed out so the back of the instrument pointed toward the firewall. The front of the tray was angled down so that it could screw into nutplates mounted on the underneath side of the sub panel. The instrument could then be slid out toward the cockpit. This setup had the instrument basically hanging from the fabricated bracket and the sub panel in between the sub panel and the firewall. You could not see it nor was it in the way of legs when sitting in the passenger seat. It was easy to reach under the panel and release the instrument from the tray. It just slid toward you and came right out.

I will try to upload a pic when I can.

Was is also attached to the firewall, or just to the subpanel?
 
I couldn't figure out where I was going to put a remote mount so I went with the GTX-335. These larger remote mount units can be a challenge for sure.

I also opted to go panel mount (GTX345) with the transponder and the GMA245 audio panel as well. Easier to mount and having all those hard-buttons at your fingertips saves a lot of digging around in the G3X. It also argues for one big screen instead of two, leaving open panel space for an iPad 11? pro on a ram mount, adding a level of information redundancy. Money and weight saved by opting out of a second G3X touch was used to upgrade to a GTN750, which, mounted in a stack moved five inches to the left of normal, becomes a pretty effective ?MDF? in its own right. To round things out, a panel-mount 507 autopilot head further reduces the need to dig around in the G3X and provides full AFCS functionallity.

Numerous photos can be found in this recent post: http://www.vansairforce.com/community/showthread.php?t=170564&highlight=Panel+graphics

I did install a remote GTR20 as com2, in much the same manner described by steve above. The GAD27 and Gad29B are stacked on top of it in the bay forward of the sub-panel on the far left, and the whole group can be easily removed as a unit for bench-servicing. I know this may not be of much use to Tom if he has already bought remote equipment, but there is a lot to be said for direct-access, hardware buttons and knobs for reducing pilot workload and keeping the pilot?s eyes outside the cockpit.- Otis
 
Was is also attached to the firewall, or just to the subpanel?
the fabricated bracket is angle aluminum mounted underneath the ribs aproximately halfway between, and running parrallel to, the sub panel and the firewall. Then two pieces of aluminum running parrallel to the ribs. Nut plates were used to hold the tray to the bracket. I will make an effort to post some pics when I can get to a computer.
 
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I have been attempting to post pictures but having difficulty with uploading to flickr. If you wish you can to send me your email maybe it would be faster if I emailed the pics to you. You can send me a PM if you wish with your email and I will send them that way.
 
Ok. I finally got things ironed out with posting these pics. Here are three pics of pretty much the same view. I know it looks a little busy but these are looking down onto everything behind the panel (on the left) to the firewall (on the right). The remote transponder tray is visible underneath and toward the passenger side of the gold colored rib and underneath all the wiring, etc. There are two pieces of angle aluminum running parallel to the sub panel and firewall. One of them is actually attached to the firewall. There are then other pieces of angle running perpendicular to those brackets that the transponder tray is mounted to via nut plates. You might notice there also is a remote mounted com radio mounted to the same brackets. Both the com and the transponder are mounted on the underneath side of these brackets and are hanging below the ribs. The front of the transponder tray is mounted to nut plates underneath the sub panel flange. This puts the transponder mounted tilted down at an angle towards the cockpit. It is easy to reach under and flip the lever to release the transponder from the tray and slide it out.



 
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