Compass calibration fails with S/N 13751

[mikelupo]

Seems that one of my ADHARS units is not taking a compass calibration.
The message is: "Calibration failed: S/N 13751"

I checked the network config and that SN is for the main ADHARS 200.
This is installed in an RV-10 in the Dynon tray with the EFIS.
@Dynon is there a remedy for this without sending it in? Today is the maiden voyage after a 4 month install.
I've not even registered it yet...

Thanks
Mike

 

[jakej]

Seems that one of my ADHARS units is not taking a compass calibration.
The message is: "Calibration failed: S/N 13751"

I checked the network config and that SN is for the main ADHARS 200.
This is installed in an RV-10 in the Dynon tray with the EFIS.
@Dynon is there a remedy for this without sending it in? Today is the maiden voyage after a 4 month install.
I've not even registered it yet...

Thanks
Mike

I’d recheck the install manual - you most likely have to install the SV-MAG-236 in addition to the ADAHRS unit to mitigate magnetic influences with the ADAHRS mounted where it is at the moment.

 

[mikelupo]

I’d recheck the install manual - you most likely have to install the SV-MAG-236 in addition to the ADAHRS unit to mitigate magnetic influences with the ADAHRS mounted where it is at the moment.

I have two SV-MAG-236 magnetometers on the shelf. I just can't install them yet as I have strobe packs in the wing tips. Those are on the way out in favor of LEDs. I am going to try the 201 today. I set it as primary and giv'r a swing. Let's see how that goes....

 

[jakej]

Also …. I’m wondering why you didn’t but the prefabricated ADAHRS mount (mounted aft of the baggage bulkhead) from Vans ? I have installed a few of them & easy to do - much easier & better than the old way .

 

[mikelupo]

Hi Jake,
I decided not to because the builder of the airplane put two antennas in close proximity of that area. One on top, and one on the bottom of the fuse. I already had pitot and static at the instrument panel along with a G5 for backup which needs the plumbing too. So rather than have to run pitot both aft and fore, as well as newly installed AOA back, I decided the quickest was to just bring the AOA up front along with the existing pitot.

Since I have replaced the right wing's strobe with LED, I can now install the magnetometer there. Should be somewhat trivial. I can build a mount and place it in the wingtip. I also have network not far away from there for the roll servo is nearby. I have an extra hub already.

 

[mikelupo]

Since my OAT sensors are installed on the fuselage in the NACA vents. I wonder if it will screw them up if I cut the wires and add a length of wires in the middle (two splices in each wire)? I figure if it throws it off, I can edit the offset for it based on the other one which will be attached to the 201. I thought I read somewhere over the last 4 months that the length of wire wasn't important. But I cannot seem to find that text to derive my own answer.
Thoughts?

 

[RV8JD]

The fuselage NACA duct on the RV’s isn’t a great place for the OAT sensor. It may be in sunlight sometimes and exposed to engine heat and cabin heat from the inside of the airplane.

Here is what the Dynon SkyView manual says on wire length and OAT location:

"Sensor Location​

The SV-OAT-340 is an outside air temperature sensor. In order for it work properly, it must be able to measure air temperature accurately. Avoid exposing the sensor to sources of heat that would interfere with outside air temperature readings such as:​

• Direct sunlight
• Engine heat and exhaust
• Aircraft interior (back side of sensor)
• Heated air from the cabin exiting from an open window or cabin air exhaust port
• The installation area should have space for a nut and wires on the back side of the sensor. It is acceptable to extend or reduce the wire length if necessary. Reduce the wire length by cutting out the desired length from the middle of the wires and splicing together the remaining ends.
• If there is a backup ADAHRS in the SkyView system, it is acceptable to install a backup OAT sensor a few inches away from the primary sensor. Consider running primary and backup OAT sensor wiring together. Tape sensor wire pairs together to avoid confusion later."

 

[jakej]

Since my OAT sensors are installed on the fuselage in the NACA vents. I wonder if it will screw them up if I cut the wires and add a length of wires in the middle (two splices in each wire)? I figure if it throws it off, I can edit the offset for it based on the other one which will be attached to the 201. I thought I read somewhere over the last 4 months that the length of wire wasn't important. But I cannot seem to find that text to derive my own answer.
Thoughts?

Mike - OAT install info is as RV8JD says, particularly the info re the NACA vents. Cabin side temps will be different & have an impact.
As for the Comms antenna placement - they do not affect the ADAHRS units ( by the way, Dynon have a simple cheap kit to enable stacking them on top of each other) from my experience.
I know its a bit of work however if it were me I’d mount the dual ADAHRS units on the Vans engineered bracket (so simple to mount with no need to use a level etc - just offer the bracket up to the position at top inside fuselage & pop rivet in place - very easy to do). Tee the pitot line, redirect the AOA & tee into the aft static lines & use a splitter cable together at the ADAHRS unit/s & you’re done. No need to use the SV-MAG-236 units at all & you have a ‘cleaner‘ more tidy space behind the instrument panel.

 

[mikelupo]

I did read that in the manual regarding the placement of the OATs.
The former OATs were previously installed there. If I move them, I will have holes in the NACA vents. I am not adverse to moving the OATs. Maybe I can use those small holes to pipe some cooling in for the avionics. In the winter when I run the heat, I worry that the avionics will suffer. Especially my 430.
I do have the ADAHRS stacking kit. I could move them. The quickest solution for me right now (in regards to compass cal) is to install the remote magnetometer. I will aim to move the ADAHRS to behind the baggage bulkhead though. I would feel a lot better with them there since it will declutter behind the panel. Getting AOA run under the baggage compartment into the aft of the bulkhead might be the more difficult part of the install modification. Penetrating the rear seat F-1005A below the flap torque tube is easy enough, but my concern there is an interim F-1034A channel (vertical between the rear seats and baggage area) that I would need to drill through and insert a snap grommet. I can't readily get to that as it's all riveted together. These are depicted in drawing 33_10. Maybe I'm overthinking that bit.
And before I sign off, thank you all for your insights and wonderful suggestions.

 

[mikelupo]

Installation of the Remote Magnetometer got me past the Compass calibration failing. I built a bracket out of some stock aluminum and attached it using brass hardware. Now when I fly south, the compass indicates south.

 

[gordonwhite96]

Hey Mike, glad it worked out. Where did you end up mounting the remote magnetometer? I'm getting ready to do the same thing soon.

 

[mikelupo]

Hi Gordon.
I mounted it in the right wingtip as far aft as I could so as minimize interference from my FlyLeds “The works” lighting.
I do suggest that you pull another network cable from a hub inside the aircraft and not extend the network cable out to your roll servo by adding a hub in the wing. Is it possible? Yes. I had to as my conduit won’t accommodate another single wire…. but you’ll have to build a network cable F-F to interface from the servo to the hub, then build another network cable to go from the hub in the wing out to the Magnetometer. You’ll have to pull separate Power/Ground for the servo as the servo does not use network power. Also, make sure that the yellow wire (AP disconnect) does not get included in the network cable that interfaces the Magnetometer. Else, the Dynon system will complain that the AP Disconnect switch is stuck.
If I had it to do all over again, I might move the ADAHRS aft of the baggage bulkhead and skip the magnetometer. My issue was getting AOA plumbing back there run underneath the rear seating area and baggage. Not sure where I’d mount the OAT sensors. Maybe aft of the static ports. Others can chime in about that.
alternatively, I think you could also run the magnetometer behind aft of the baggage bulkhead If getting AOA run back there is too much of a pain (as it is for me).

 

[gordonwhite96]

Thanks for the detailed reply. I think I'm going to shoot for mounting behind the rear baggage bulkhead (Vans RV6). I have the extension cable on hand already, hopefully I'll get after it next week.