AOA and elevator position data

swatson999

Well-Known Member
Joined
Oct 6, 2010
Messages
1,689
I see where SavvyAnalysis is now able to display quite a few more parameters, which are interesting to analyze post-flight.  One or two quick questions...

I see AOA and Elev Pos expressed as %.  In cruise, my data shows AOA of 0 and a negative value (-17) for elevator position.  What, exactly, is being measured here?  Percent of full travel?  And is it *elevator* position, or *elevator trim* position?  What does a steady AOA of 0 mean, and is that real, or simply that the AOA sensors are reading off-scale low?

Data is here:

https://www.savvyanalysis.com/flight/1265062/fe4cbdd9-6552-44b4-b725-4f0cd9a33511
 

dynonsupport

Dynon Technical Support
Staff member
Joined
Mar 23, 2005
Messages
13,226
Assuming Savvy isn't manipulating the data from our datalogs, than the definitions for all of our datalog data are in Appendix E of the Install Guide. If they are changing it, then you'd need to ask them.

We store both the actual elevator position and the trim position. So we don't know which one they are showing either. However, looking at your data it's pretty clear that is trim, not actual elevator position. Did you fly full up elevator for the last 4 minutes of flight? ;)

From appendix E:

AoA:
00 to 99, percentage of critical angle of attack.

Trim:
T if the signal is position
[ch61623] If elevator, rudder, and aileron trim, YYYY is percent travel, so 0047 = 47%

Trim is percent travel on each side, so it goes from -100% to +100%, with 0% in the center, based on your calibration. Your trim goes from -18% to +75% over that flight.
 

swatson999

Well-Known Member
Joined
Oct 6, 2010
Messages
1,689
Assuming Savvy isn't manipulating the data from our datalogs, than the definitions for all of our datalog data are in Appendix E of the Install Guide. If they are changing it, then you'd need to ask them.

We store both the actual elevator position and the trim position. So we don't know which one they are showing either. However, looking at your data it's pretty clear that is trim, not actual elevator position. Did you fly full up elevator for the last 4 minutes of flight? ;)

No, just on the ground while taxiing...as I was taught with nosedragger RVs :) ("Stick to the d*ck!")

But yeah, I figured it must have been trim position given how unchanging it is (I'm not *that* smooth of a pilot LOL).

Thanks...I should have looked in the installation manual, of course.
 
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