What is this control for?

[amchale]

Hi all, I noted that a lot of panel-modified Jetprops have this little switch labeled "yaw trim" next to the prop sync control. Does anyone know what this is for? It looks like an electric trim switch but I was under the impression that the Commander only has electric pitch and roll trim, and the yaw trim is accomplished with a wheel on the cockpit overhead panel. Is this an electric trim modification for the rudder?

[donv]

Is that something to do with the G950 system? I've never seen that, but then I've never flown a G950 Commander.

[amchale]

It appears so but I am not sure. I recall having seen it on other non-G950  commanders with new panels but I am not positive.

[Bruce Byerly]

That’s the typical Stec yaw trim. Standard with every 2100.

[amchale]

So the STEC auto trims the rudder? Not just yaw damping?

[donv]

Interesting. The 3100 doesn't have that.

[appleseed]

My experience in the 441, No it doesn't autotrim, it uses the servo to fight the trim tab to zero the yaw. It is annoying, as you change speeds or power the rudder gets out of trim. There is no way to know how out of trim you are without disconnecting the yaw damper. Which always happens with a jolt. Most pilots develop a ded-reckoning way of knowing how many swipes to take as they transition from climb to cruise etc.

It is a super effective yaw damper though.

[donv]

I believe they redesigned the entire yaw damper system for the 3100, which from everything I have heard is a good thing. It is interesting to hear about the 2100.

[seanmcgillivray]

DonV you are correct. The 3100 eliminates this. I currently have the 2100 and the rudder gets out of trim, it provides a nice jolt when you disconnect.

The 3100 upgrade (just got my parts this week) will eliminate this.