Compass lead/lag

Tom_D

New Member
Joined
Aug 17, 2006
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3
During my flight testing I have noticed my EFIS 100 acts much like a compass (with about 1/2 the lead/lag degrees) when turning to a heading of North or South.  Just like the wisky compass the E and W turns are ok.  I has been my impression the the EFIS should show a "gyro stabilized" turn.  I have re calabrated my EFIS using a local compass rose and the headings seem to be right on or very close.  I have checked and rechecked my inclination dip.  This could be quite concerning when used for instrument or precision turns.  Any Suggestions?
 

dynonsupport

Dynon Technical Support
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Mar 23, 2005
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13,226
The heading on our EFIS-based products is gyro-stabilized, so it's surprising that you're seeing this behavior. If you turn to the North or South and the heading lags, does it eventually stabilize to the correct heading? If so, how long does this take?

Let me know those things and we'll proceed.
 

Tom_D

New Member
Joined
Aug 17, 2006
Messages
3
Yes it lags while turning North and leads while turning South-just like a compass but at about half the amount of degrees. It only takes maybe 8-10 seconds to stabilize on the correct heading. As you know 8 seconds in instrument conditions is long enough to become disorentiated. Thanks for your help on this.
 

dynonsupport

Dynon Technical Support
Staff member
Joined
Mar 23, 2005
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13,226
One thing that can produce some strange effects is calibrating the heading before entering the correct magnetic inclination angle into the EFIS. For the US, this is a number roughly between 50 and 70.
 

Tom_D

New Member
Joined
Aug 17, 2006
Messages
3
As stated I have checked and rechecked my inclination angle at 67* for my airport and then recalabrated on our compass rose. Heading seems to be right on once it is settled down. Do we need to talk?
 
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