D10 EDC Accuracy?

[LedSled(Guest)]

Hi Folks,

I'm trying to puzzle my way through a D10 installation on a CH-300. The EDC is properly mounted and isn't near any power wires etc in the tail of the aircraft. It doesn't read accurately, ie it's always out by 10-15 degrees, and not always in the same direction. Our local magvar is 13W, so I thought this was the culprit, but one day it'll read 15 degrees east of the wet compass, and the next day it'll read 10 or 15 degrees west of the wet compass, whilst flying on the same heading. I'm puzzled. Are these things just naturally only a "wet finger in the air" kind of compass, or are they capable of real accuracy in magnetic heading?

My question to the general group is "just how accurate is your D10 compass indication when using an EDC-10?" Note, this is not an "A" model, it's the original D-10.

My question to Dynon Support is "is there a way to make the heading indication NOT slave to magnetic north, ie the equivalent of the good old 'slave/free' modes like on a C-12 compass?" For those of us who might be flying in the "area of compass unreliability" this would be a wonderful thing to have!

Thanks to all for your helpful responses.

 

[meljordan]

I'm sure the folks at Dynon Tech support will also respond to this, but I can tell you that the heading indications in my plane (I have both a D10A and a D100) are the most accurate compasses I have ever had, both are within 2 degrees of true for the entire 360 compass. Have you done the calibration routine in the installation manual? If so and you are still seeing these sort of readings, then something is definitely wrong.

Best Regards,
Mel Jordan
RV-6A Tucson

 

[dynonsupport]

LedSled,

As Mel mentioned, we expect the EDC to be really accurate. It's a true magnetic reading, and in fact reads magnetic fields in all threee axis, so it is accurate even when the airplane is not level. It should be better than just about any compass you have ever seen.

The EDC is not calibrated at the factory though, so you do need to do a calibration on it. The first thing to check is that the EFIS is using the EDC. The best way to do this is put a magnet near the EFIS and see if it swings. If it does, the EFIS isn't using the EDC for some reason. The internal compass is really, really not calibrated from the factory, so it can act totally weird.

If you've calibrated the EDC, and the EFIS is using the EDC, and it's still moving around, this is most likely due to the EDC being too close to a wire or a moving ferrous part, like a bolt on a control rod. On the ground, turn on the EFIS and then move your controls and turn on/off different loads and see if anything changes the heading. We can calibrate out things that are alwasy there, but not changing magnetic fields.

The magnetic variation won't have anything to do with it, and we don't support a way to take it out. We point to magnetic north, just like a wet compass does, and just like the controller will expect you to fly when he give you a heading. There's also no way to un-slave the heading from the magnetic sensor- we really do expect that the EDC will work really well.

There's always a chance something is broken in your EDC or EFIS, so if you continue to have problems after trying a few things, please give us a call or a message here and we'll keep working on it with you.

 

[vlittle]

I mounted my EDC in the aft fuselage of my RV-9A slider. After calibration on the ground using a compass rose, I had significant errors in flight.

I turned out that when calibrating, my canopy was open. The steel frame of the canopy rolled right back over the EDC location and caused magnetic deviation.

I changed my calibration procedure to make sure the canopy was nearly closed, and reached in with a paint stirring stick to push the buttons on the D10A. This improved the calibration.

One of those 'Du-Oh!' moments.

Vern Little 9A