ADAHRS primary and secondary discrepancy when looping

[Plopper]

In most cases when performing a standard looping (approx. 3-3.5G) I get a SkyView warning (just after flying level again) that my ADAHRS modules differ. When I press 'compare' both ADAHRS show the same values (again), so I can safely ignore the warning.

Up to now I have only had this behaviour when performing loops. No problems whatsoever in normal flight or doing other (light) aerobatics such as barrel, aileron or snap rolls or spins/spirals etc. Both (primary and secondary) ADAHRS-es are stacked in the same location (using Dynon's standard stacking plate), inside the airframe, well away from any magnetic interference or moving parts.

I am not really concerned that anything is wrong or defective, but just curious if anyone has experienced the same?

Best regards,

Roel

 

[RVDan]

There are pitch and roll rate limits to the adahrs units. I don’t recall what they are, but have also experienced this during aerobatics. FYI, all non-military adahrs and ahrs units that I know of have rate limits.

 

[Rhino]

Pilot error. You made them loopy. Dan probably has it right. They aren't really designed for aerobatics. Now, if they do that in normal flight.....

 

[RV8JD]

Info from the User's Guide on rate limits:

"Attitude Rate Limit
SkyView’s ADAHRS will operate normally at rotational rates of up to 150 degrees per second in
any axis. If the aircraft’s rotational rate exceeds 150 degrees per second – as can happen in a
well-developed spin or when performing aggressive aerobatic maneuvers – the PFD page will
annunciate “ATTITUDE RECOVERING”. During this time, SkyView’s attitude indication may be
degraded and other instruments should be used to maintain safe flight.

After straight and level flight is restored for a few seconds, the ATTITUDE RECOVERING message
will disappear. Full performance of the attitude indication is restored. This requires no
additional action by the pilot."

Screenshot from my SV Touch during a flight shows the 'ATTITUDE RECOVERING' message on the PFD: