06 March 2016

Avionics: Magnetometer bracket fabricated and installed.

The GRT magnetometer must be mounted with a significant distance from objects that can disturb the ambient magnetic field.  GRT recommends placing the magnetometer in the wingtip.  I prefered to keep it in the fuselage as it would make future mounting of the AHRS easier.

The location I chose was in the aft fuselage, just forward of the ELT.  It turns out that the F-01418B-L/R Aft Fuse Longerons have holes drilled in their upper flanges to accommodate wire ties.  I found that I could those holes to mount a tray to support the magnetometer.  I used the two holes on each longeron circled in red.


For the tray and mount, there was no need to purchase additional aluminum.  The cross-members were fabricated from the C-01442B Mid Canopy Fixture, that was used to temporarily affix the canopy frame. The tray was fabricated from some RV-9 capacitive fuel plates I had laying around.  To locate the holes properly to the Aft Fuse Longerons, rather than risk match-drilling into the latter, I simply cut the cross member to length, then rested them on the Aft Fuse Longerons over the holes.  I push grease up into the holes, which then remained on the cross members.  This allowed the holes to be drilled into the cross-members without bringing a drill near the Aft Fuse Longerons.  Below is the top (left) and bottom (right) of the fabricated mount.


The mount with magnetometer as viewed from the turtle deck.  It is attached to the Aft Fuse Longerons with four LP4-3 rivets.  The magnetometer is secured to the tray with nylon screws and nuts with a dab of Loctite.


The mount with magnetometer as viewed from the baggage area.


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