Autopilot/Auto trim in flight

AlanR

Member
Joined
Jan 25, 2007
Messages
167
Location
UK
My autopilot with autotrim flies my aircraft, Bristell NG5, very well except that I do notice that when the autopilot/auto trim is engaged the aircraft flies 3-4knots slower than when I hand fly and hand trim the aircraft.
I suspect that autotrim is trimming the aircraft just very slightly nose high so a little adjustment somewhere would improve things.
How can I rectify/improve this?...Autotrim configuration in the manual doesn't seem to cover anything appropriate.

Thanks,

Alan.


 
 

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
13,875
Location
Woodinville, WA
One thing to test this - disengage the AP when it's fully trimmed out and not commanding any trim (ie, it's happy). Is it in trim? Know that the auto-trim endeavors to fly the airplane in trim, but that is necessarily a range where the residual force on the servo is "low enough". So one thing you can do if you think it's keeping it slightly out of trim nose high, is to bump the trim yourself a little bit lower. If that yields a low enough force such that it's still within the "low enough" window, you'll end up with your desired behavior. If the autotrim just winds it back out, then that's a little more puzzling. In any case, starting with what the airplane does when you disconnect the autopilot will be helpful. Note that we wouldn't expect it to be absolutely "perfectly" in trim, but it should be very close.
 

AlanR

Member
Joined
Jan 25, 2007
Messages
167
Location
UK
Ok, thanks for that input. That is a good idea.
I will try as you suggest and report back on what I find.

Alan.
 
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