erratic compass and airspeed

[Brudy61]

This is a new install of the Dynon HDX, com radio, ADHAR, Xponder, remote auto pilot panel, knob panel, remote radio panel, dynon net work, EMS, Arinc 429, Garmin GPS175, Dynon heated pitot tube, etc. All the goodies.
The plane is a Sport Cruiser, the existing wire harness, trutrak glass panels, auto pilot servos, etc. was removed.
Compass was calibrated on the ground and in the air.
Stall speed calibration was performed.
Airspeed is erratic at lower speeds, seems to settle out at or before cruise, gets erratic in the pattern, and is reads faster the GPS on a calm day.
Compass swings erratic - the auto pilot is trying to follow compass heading.

May consider moving and or adding second ADHAR.

Help?

 

[lancair360]

Did you do the zero airspeed calibration on the ADAHRS too?

might settle the compass too since it's not just a basic ahrs.

 

[Brudy61]

I did zero the airspeed in the calibration, with the pitot tube covered.
I will recheck that calibration and look into a possible air leak from the pitot tube lines, how ever that wouldn't disrupt the compass.

Let me add their is noise in the head phones when the AP is applied, how ever the compass is erratic regardless of the AP on or off.

 

[lancair360]

Static port coverec for zero airspeed check as well?

Also at lower speeds, airspeed erratic, I wonder if it's an AOA issue or static port placement issue?

Check for leaks, go from there. One thing at a time

 

[Brudy61]

I moved the Remote Magnetometer to an area behind the seats, The compass is holding heading great now.
Need to check the pitot tube and static port tubing for leaks yet, the air speed is still erratic.
Auto Pilot is not happy, when in use head phone have noise until AP disconnect is applied.
Dynon suggested checking if the AP servo wires run with head phone wiring, Removing zip ties and powering up HDX screens and AP then shifting wires around to see if the noise changed, no change in the noise.

 

[lancair360]

Check wire runs yes. Also might need to shield some wires. Check grounds as well on the headphone connections. Bad grounds will ruin everything and can be hard to find.

 

[Brudy61]

Airspeed is reading fast by 7 knots or so.
Anyone have issues with the static port location with regard to airspeed?

 

[Brudy61]

Fixed airspeed.
The cause was the static ports mounting location.
For a test the static lines where removed at he static port located on the exterior of the airplane.
Airspeed is accurate now.