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Sport with the leans

Postby slambert » Sun Sep 21, 2014 9:39 pm

I have a few hundred hours on my Sport SX and it's never blinked but while on a short local flight last week it got the leans. ( 20 degrees or so ) I reset the box inflight and it the problem remained. The magnetic heading was not even close to correct. I landed and performed a magnetometer calibration and flew a short flight and it seemed to work correctly.

I updated the EFIS and AHRS to the current release in the last five flight hours. This flight was the first in rough air.

Has anyone else seen this and what should I look for if it returns?
slambert
 
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Re: Sport with the leans

Postby GRT_Jeff » Tue Sep 30, 2014 7:30 am

How did you reset the box? When you hold the outer buttons, only the main display software resets. The AHRS would not be reset that way. To reset the AHRS in a Sport you would have to turn off power to the display.

Make sure the display is showing AHRS software 43 (0.43). If the cause involves short bursts of magnetometer interference, that should only affect older software.

Where is your magnetometer mounted? If it's near any control linkages, make sure you can move the controls around without affecting the Magnetometer Heading on the SET MENU, AHRS Maintenance page.

Were you doing any extra COM transmitting?
GRT_Jeff
 
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Re: Sport with the leans

Postby MidgetMustang » Tue Dec 30, 2014 7:24 am

Hello Jeff,
Hopefully you have resolved your issue already. If not, I have experience with Sport 'leans' that may be useful. My Midget Mustang has very few places that can accommodate the magnetometer's clearance requirements and it has an attitude indication error. Since I'm stuck with a troubled magnetometer location, I've been watching this forum and the old Yahoo forum since 2009 for precious clues on other solutions. One individual solved his problem with a shielding material called mu-metal. The rest have simply moved the magnetometer until it started working. In atleast one case, a good magnetometer location was corrupted which caused a previously stable attitude indication to become bad.
Good Luck,
Brad
MidgetMustang
 
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Re: Sport with the leans

Postby TWRanger » Sun Jan 25, 2015 6:54 pm

We are having the same problem with the EFIS showing a 5-10 degree right bank in level flight. We have a RV-9A with the magnetometer located in the right wingtip. On start-up and when taxiing, the EFIS seems to show correct attitude. After takeoff, we start seeing the lean. We can sometimes correct this attitude issue by initiating a relatively steep (45 degree) 360 degree turn. Sometimes (not always) this will eliminate the leans and the EFIS will show the correct attitude for the rest of the flight. Also, it appears the more turning we do, the more accurate the attitude indicator becomes. Understanding the logic used to determine attitude in the Sport SX EFIS would be very helpful in troubleshooting this issue. We have tried re-calibrating the Magnetometer, but that doesn't seem to make a meaning difference. Any insights would be wonderful!
TWRanger
 
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Re: Sport with the leans

Postby GRT_Jeff » Thu Feb 19, 2015 3:52 am

On the ground, the accelerometers and magnetometer are used to align the attitude and heading. When in flight, it also uses airspeed. Normally the magnetometer is the only heading reference. If there is any long-term error in this data, it will throw off the attitude or heading. Usually the magnetometer is the most significant source of error. If it happens every time, you can use the DEMO RECORD function to start recording the data before takeoff and then switch the DEMO button back to STOP to save the data to a USB flash drive. You can e-mail the file to us to look for any problems in the data.
GRT_Jeff
 
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Re: Sport with the leans

Postby MidgetMustang » Wed Apr 01, 2015 3:17 am

TWRanger wrote:We are having the same problem with the EFIS showing a 5-10 degree right bank in level flight. We have a RV-9A with the magnetometer located in the right wingtip. On start-up and when taxiing, the EFIS seems to show correct attitude. After takeoff, we start seeing the lean. We can sometimes correct this attitude issue by initiating a relatively steep (45 degree) 360 degree turn. Sometimes (not always) this will eliminate the leans and the EFIS will show the correct attitude for the rest of the flight. Also, it appears the more turning we do, the more accurate the attitude indicator becomes. Understanding the logic used to determine attitude in the Sport SX EFIS would be very helpful in troubleshooting this issue. We have tried re-calibrating the Magnetometer, but that doesn't seem to make a meaning difference. Any insights would be wonderful!


Sounds like my issue. I imagine that when we start turning and pulling on the stick the accelerometers provide a lot of information to the algorithm which is then able to create an accurate attitude indication. Straight and level probably relies heavily on the magnetometer, since the accelerometers are just sitting there. In my case the heading indication from the magnetometer is really good, so that's a bit of a mystery to me.

Good luck and please post any wisdom that comes your way.
MidgetMustang
 
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