[sf3543]

Has anyone installed the garmin AHRS (GSU 73) behind the instrument panel?
Someone said it won't work here but the installation instructions don't have an issue with it. Since garmin is closed for the holidays, I was looking for input from someone with real life data. It is for a G3X system.
Thanks

 

[UnPossible]

In my RV-7A, I've got the GSU73 mounted right behind the panel (see pics below). I've got ~70 hours on the plane now, and it is working great.

Hope this helps,
Jason

 

[Brantel]

Has anyone installed the garmin AHRS (GSU 73) behind the instrument panel?
Someone said it won't work here but the installation instructions don't have an issue with it. Since garmin is closed for the holidays, I was looking for input from someone with real life data. It is for a G3X system.
Thanks

The GSU73 can be installed there but it needs good solid mounting to the airframe. Since the EMS harness connects to it, it is the natural place for it to belong.

Many people have installed them there.

Most likely what they were talking about is the GMU44 magnometer. Behind the panel would be a horrible place to mount that. Out on the wing tip or on the shelf under the horizontal stabilizer are the typical mounting places for it.

 

[Brantel]

In my RV-7A, I've got the GSU73 mounted right behind the panel (see pics below). I've got ~70 hours on the plane now, and it is working great.

Hope this helps,
Jason

Jason,

Please duplicate your mounting brackets and send them to me!

I plan to do very similar to how you have yours mounted.

How did & where you mount the remote xponder if that is what you are using?

 

[sf3543]

Brantel
I agree with you. GMU 44 is in the tail and GSU 73 is solidly mounted similar to Jason's picture.
Thanks for the feedback!

 

[sf3543]

Jason
Thanks for your reply and pics!
Great minds think alike!!!

 

[UnPossible]

How did & where you mount the remote xponder if that is what you are using?

I do have the Garmin remote transponder, and its mounted on some AL angle between the panel supports. I hinged the angle nearest the firewall so that the panel will drop down and I can easily slide out the transponder if it ever needs to come out for service.

Below are a few pics.....

 

[mburch]

Between the panel and firewall is pretty much the ideal place for the GSU 73 in side-by side RVs or the RV-10, due to EIS sensor wiring requirements. (The RV-8 might be able to mount it under the forward baggage floor, assuming space is available).

One comment on the mounting arrangement shown above, if this was my airplane I would feel better if the AHRS unit was solidly mounted without using a hinge, and if its mounting shelf had some longitudinal stiffening angles running underneath. My opinion only.

For what it's worth, the folks who know have told me that in a typical certified installation that uses a related AHRS unit, they usually use a heavy steel bracket that weighs over a pound all by itself. Food for thought.

mcb

 

[UnPossible]

One comment on the mounting arrangement shown above, if this was my airplane I would feel better if the AHRS unit was solidly mounted without using a hinge, and if its mounting shelf had some longitudinal stiffening angles running underneath. My opinion only.


mcb

Sorry if I created any confusion, but the GSU is not on a hinged mount.... it is mounted on a pretty beefy mount that attaches securely to both the panel and the sub-panel (I think there are 3 or 4 screws attaching it to each side).

The remote transponder is mounted on a hinged mount that can drop down when the front screws are removed...... its pretty secure, but I agree, not good enough for a GSU.

Thanks,
Jason

 

[Bill.Peyton]

Ours is mounted between main and sub panel. The tray has angle sides for reinforcement and is attached to the main and subpanel rails with 6-#8 hardware. Washers are used to shim the tray for level with aircraft level. Below is a photo.

 

[BillL]

Building, but here is mine . .

I have been wrestling with this same thing. My 44 is mounted in the rear of the plane. I wanted to mount the 73 where it could be accessible, and the -23 could be removed. A hinge seemed to be clever, but maybe not so solid to take vibration and 6 g's. I concluded that it would be between the F745's on my tip up. The next hurtle was strength and deflection. I took an online calculator and approximated the area moment of inertia and then used a different online calculator for stress and deflection. Each component weighs approx. 3 lbs, and using 6 G's , that totaled 18# on each beam. I assumed worst case with 18# concentrated in the center. The online calculator indicated .0017" deflection.

The angle is 3/4 X 1/16 and the web and top flange are .025. bent and riveted.

The -23 and -44 are mounted for installation and removal from below. #6 for then-23 and #10 for the -73. I will use countersunk screws to align the 73 to ensure proper geometric heading alignment.

Comments for improvement or issues are welcome.

Here are the photos:

Clamped in place:

Ready to install.

Beam view (fuzzy) and nutplates.