ADAHRS ferris metal rule?

[bret]

Installing the Dynon ADAHRS and they want at least one foot from any ferris metal, but the wire harness for that unit has steel right there on the D 9 connector that plugs into it. So is this rule only apply to steel objects that move? If so, then why all the worry about non ferris fasteners to mount the unit, just curroius.

[luddite42]

Originally Posted by bret

So is this rule only apply to steel objects that move?

Definitely keep it away from ferris wheels.

[newt]

Sage advice.
http://www.smh.com.au/nsw/ferris-whe...129-1o4qu.html

- mark

[Snowflake]

I wondered about that when I installed my remote compass module, too. The shell on the DB9 connectors, and the screws and hardware holding it in place, are all steel of some kind.

It seems to work though. Perhaps the hardware isn't a magnetic grade of steel? I didn't check that.

[airguy]

Were those the Dynon-supplied cables?

I built my own cables, using the plastic backshells from Stein. The DB9 connector itself does have a small steel shell on it. Steel in and of itself is not inherently evil - magnetized steel is what you are worried about. If it's non-magnetized you are mostly OK, though it's admittedly difficult to null out ALL the field in most pieces of steel.

I had a conversation with Dynon when I was installing my ADAHRS about a year ago, they are concerned about constant magnetic fields in the area to some degree (those can be partially calibrated out) but they seemed to be more concerned with variable magnetic fields to a larger degree. Variable fields would be generated by any ferrous metal that is magnetized and moves around in flight, or by electrical currents in close proximity to the ADAHRS. The tail section just forward of the fairing seems to be one of the most magnetically stable environments for an RV, that's where I mounted my Dynon and MGL boxes. Notice the brass screws holding the boxes down - nonmagnetic.

[IMG][/IMG]

[bret]

Originally Posted by airguy

Were those the Dynon-supplied cables?

I built my own cables, using the plastic backshells from Stein. The DB9 connector itself does have a small steel shell on it. Steel in and of itself is not inherently evil - magnetized steel is what you are worried about. If it non-magnetized you are mostly OK, though it's admittedly difficult to null out ALL the field in most pieces of steel.

I had a conversation with Dynon when I was installing my ADAHRS about a year ago, they are concerned about constant magnetic fields in the area to some degree (those can be partially calibrated out) but they seemed to be more concerned with variable magnetic fields to a larger degree. Variable fields would be generated by any ferrous metal that is magnetized and moves around in flight, or by electrical currents in close proximity to the ADAHRS. The tail section just forward of the fairing seems to be one of the most magnetically stable environments for an RV, that's where I mounted my Dynon and MGL boxes.

Yes, Dynon supplied cable for the ADAHRS, one end made up, pins on the other, the base is steel of some kind, and plastic housing.

[Walt]

I can't wait to crawl back there to fix a static leak

Originally Posted by airguy

[IMG][/IMG]

[airguy]

Don't worry, I won't ask ya to!