Version 11.1 Trim nose up (or down) too sensitive

[Knd]

I own a light sport and only have a pitch trim (other 2 axies are bendable tabs).

While flying yesterday, when I reached forward to tune the radio, I would get a trim nose up message. When I leaned back the warning would disappear without adjusting the trim.

This happened every time I would reach forward. I knew it was more sensitive than version 10.1, but yesterday was able to see just how much it took to trigger the message.

Is the sensitivity adjustable ?

 

[dynonsupport]

You didn't state which of our systems you have, but yes, there is a SENSITIVITY adjustment in the PITCH axis. I suggest noting what the setting is currently so you can restore it if necessary, then adjusting it very incrementally.

I own a light sport and only have a pitch trim (other 2 axies are bendable tabs).

While flying yesterday, when I reached forward to tune the radio, I would get a trim nose up message.  When I leaned back the warning would disappear without adjusting the trim.

This happened every time I would reach forward. I knew it was more sensitive than version 10.1, but yesterday was able to see just how much it took to trigger the message.

Is the sensitivity adjustable ?

 

[Knd]

Thx. I have dual SV 10". I thought the sensitivity was how it reacted to restore/maintain altitude, not how frequent the trim messages appear.

I'll definitely record the current setting and adjust to see the sensitivity.

Thx.

 

[dynonsupport]

Knd,
Sorry, the sensitivity does adjust how the AP flies the plane and has nothing to do with the trim alerts sensitivity. Someone must have mis-read your post.

There isn't any adjustment for the alerts. The newer software didn't make them more sensitive- it made them more accurate. A lot of small planes are remarkably sensitive to CG. I flew 30 minutes making turns and 1,000 FPM climbs and descents once just by shifting around in my plane. So I'd say it's doing what it is supposed to. If you trim your plane, turn off the AP, and then move around, you might be surprised how much you are changing the trim requirements.

You may have also been just against the edge of the trim announcement, and the weight shift was all it took to trigger it. In that case, a tap of the trim would solve it. You could have also been bumping the controls.

 

[DBRV10]

Dynon Support - who specifically wrote this reply above.

Can you go to see Lawrence Doan, he knows all about this bug with the trim flagging. I have it in rather annoying doses, and if I follow the flag and trim as it wants, it asks for more, then more and eventually you are a long way out of trim.

This is a known problem which he is working on. Perhaps some data files from others might help.

Knd is not alone :-/

 

[dynonsupport]

Knd is reporting that the trim comes on when he leans forward in the plane, and it goes off when he leans back. I'm not sure I see a bug there like you describe David. It sounds like it's properly reporting a trim change in the plane.

 

[vlittle]

The small aircraft that most of us fly are in constant need of trim adjustments, with or without an autopilot. Ideally, you'd engage the AP once the aircraft is fully stabilized and you would only ocassionally be asked for trim adjustments.

However, i'm just not that patient. I usually snap on the AP before speed and trim is stabilized and let my autotrim controller do all the fussy work for me as things stabilize. I know that Dynon is working on an autotrim upgrade, so they will eventually catch up. In the mean time, my M-PWR-2AT is capable of running a 2-axis auto-trim system and is easier to install.

Vern

 

[DBRV10]

I understand the trim change when leaning forward and back, but that might just be part of the puzzle with the new trim sensing.

Leaning forward and back in any plane should not mean a retrim, the A/P should cope with that. Unless it is severely under sized servo or the torque setting is too low.

There is a bug…..whether he is part of it is another matter.

 

[preid]

I think if many were having this issue it might be a bug, but since this is a isolated issue it may be more of a need to make the adjustment.
Knd
I assume you did the AP tuning via the guide? If not do so and see if that changes the alerting, as a start.

 

[Knd]

I understand the trim change when leaning forward and back, but that might just be part of the puzzle with the new trim sensing.

Leaning forward and back in any plane should not mean a retrim, the A/P should cope with that. Unless it is severely under sized servo or the torque setting is too low.

There is a bug…..whether he is part of it is another matter.

I'm with Dave. Let me clarify some. I've had my system since January of 2012 with the same pitch servo. I beleive it was SV version 3.0 then.

I have never had to constantly trim the pitch axis and on a 2-3 hour cross country on AP I may have to trim it once based upon an alert.

2 days ago I would have been bumping the trim more than 10 times during the flight. Fortunately, I figured that my weight shift was causing this. Thus the title of my post.

I'll check the pitch servo to see if there is some installation problem (mount came loose?), but this wasn't my first flight with 11.1 and I noticed it seemed to be giving more alerts, but on my last flight I figured out just how sensitive it is, in my plane at least. I got more alerts with 10.1 than version 9 of SV.

For me, version 9 and below was right on the nose up, nose down trim alerts.

 

[DBRV10]

What the trim flag shows is a content need to retrim when you disconnect the autopilot the plane is in perfect trim.

On many occasions the trim flag keeps flagging and if you follow the instruction you get very out of trim. And that is fun when you disconnect.

Knd,

Make sure you get the flags and capture the data within 30 minutes of it happening, and download the Dynon Diagnostic file to a USB stick. You can do this in flight, as it only holds 30 minutes of data.

Upload it to Dynon via their upload page on the website. Make reference to me and send the file to Lawrence Doan. He will be keen to see it.

 

[Knd]

Update: previous flight all seemed normal. Went out this morning and the trim up and trim down messages were oscillating without any input from me so I downloaded the diagnostics file to a memory stick.

During the download process (which takes some time) my roll servo apparently failed. When I landed I rebooted the system, set the autopilot and the pitch servo engaged but not the roll servo. I checked the network and both servos were "ready".

I'm going to call support.