Remote compass installation for D6

glasair

New Member
Joined
Oct 8, 2009
Messages
33
The installation instructions refer to trying to get the pitch alignment to be accurate to within 1 degree between the remote compass and the main unit mounted in the panel. Can we take the front mounting bezel of the D6 unit to be the reference for pitch of that unit. I.e. is the internal stuff aligned to the front bezel?
I would assume that is so, otherwise how would we know what to align the magnetometer. I plan on putting a protractor level across the front of the D6, measuring the angle, and setting the pitch of the remote compass to match as best as I can. I have access to lasers and optical instruments and can do it to much greater accuracy if necessary, but how accurate are the internals of the D6 aligned to the mechanical case of the D6 anyway.
Another question, how accurate does the remote magnetometer have to be aligned in the roll and yaw axes to the D6. Roll would be relatively easy, using the same level in the orthogonal direction across the top of the bezel of the D6 to establish the reference, and then across the top of the case of the remote compass (parallel to the long direction of the aircraft wings) to level the remote compass along its roll axis. The yaw axis could be the most difficult. I could establish the centerline of the aircraft and align to that, but that assumes that the instrument panel is perpendicular to the centerline of the aircraft. Of course, I could also measure the tilt of the instrument panel and take that into consideration.

In summary, I would be good to have knowledge about what remote compass mounting alignment "errors" are calibrated out during the ground and in-flight calibrations and just how much these errors will affect the final accuracy of the compass.
 

dynonsupport

Dynon Technical Support
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Mar 23, 2005
Messages
13,226
Yes, you can use the bezel as a reference. If it's bolted to the panel, you can also use the face of the panel as well. An inexpensive digital level like the ones you can get from Harbor Freight or other discount tool suppliers will work fine for dialing in roll and pitch.

The spec for all axes is within a degree, and the calibration is broadly designed to deal localized interference, not gross misalignment. If you are off on yaw by a degree or two, though there is a "MAGADJ" setup menu item which lets you "spin" all of the numbers around in software. Use that AFTER calibrating if there is some residual error which is constant and always in the same direction.

Most people just align it with some part of the aircraft that is supposed to be straight and that works well enough.
 

glasair

New Member
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Oct 8, 2009
Messages
33
Great reply. Now I understand. Just one more thing. The D6 installation manual talks about the detailed flight alignment if you don't have the external remote compass, but I thought that the external compass is mandatory with the D6.
 

dynonsupport

Dynon Technical Support
Staff member
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Mar 23, 2005
Messages
13,226
The compass isn't mandatory with the D6, but it is included with the price. If you really don't want to install it, you can use the internal compass.
 

glasair

New Member
Joined
Oct 8, 2009
Messages
33
Didn't catch the fact that there was an internal compass in the D6.
I would assume the external one might be more accurate, as it is can be installed in a more benign magnetic environment and the calibration is certainly easier.
 
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