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Which bulkhead for GMU-11, in 9, 6, or 7?

thinkn9a

Well Known Member
Wondering what bulkhead(s) have been used and results. ( just forward of tail or just aft of baggage bulkhead)

Also interested in any tips or recommendations for mounting.
 
I put mine just aft of the baggage bulkhead. Just test flew a week ago Monday and it seems calibrated just fine. I used the "new" Van's mounting bracket.
 
GMU-11

From the Garmin G3X and Touch Installation Manual Page B-2
"The typical GMU magnetometer mounting location in RV-7/9 aircraft is in the aft fuselage on the aft deck (F-714) just ahead of the horizontal stabilizer and just aft of the F-709 bulkhead. This location provides a level pitch and roll reference, and acceptable separation from excessive magnetic disturbances in typical RV-7/9 aircraft."

The GMU-11 can be mounted with the connector forward, aft, left or right. I mounted mine with the connector to the left and there is sufficient room on the aft deck for the four mounting screws without the need for an additional bracket. The G3X must be calibrated for the appropriate connector location of the GMU 11
 
I have tested the mounting location for the magnetometer in my RV-9A aircraft on the aft fuselage deck (F-714) just ahead of the horizontal stabilizer and just aft of the F-709 bulkhead with a calibrated electromagnetic radiation tester. - where mine is mounted. The results were effectively zero/negligible readings of possible interference - and certainly not measurable. I tested the position, aft of the baggage bulkhead, which also gave zero/negligible readings of possible interference.
Hence it seems that for a standard setup, either location is suitable.
 
I mounted my GMU11 aft of the baggage bulkhead using Van's bracket. It calibrated just fine. If nothing else, that location resulted in shorter wire runs.
 
Antennas and Servos?

Anyone who has tested the GMU just aft of the bulkhead - do you also have a Garmin GSA 28 pitch servo just aft of the baggage panel and any antennas on top of the aft fuselage?

I would like to mount my GMU11 in the fuselage using the new Vans ADAHRS bracket. I have an RV7 with GSA 28 pitch servo and a GPS antenna on top of the fueslage.

However, Table 15-4 of the Garmin install manual says I need 10 ft seperation between the GMU and any servo motor and 3ft to any device drawing more than 100mA which I think antennas do.

So that means that placing the GMU in the place recommended by Garmin for an RV7 conflicts with Table 15-4.

I wonder if anyone has any real world experience with this set up?
 
Some body once said that the only way to follow all Garmin's recommendations on mounting magnetometers would be to place them several feet outside the frame of the aircraft ...
 
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