Is rudder trim tied to legacy AP?

[warrenehc]

Hello, new owner here.

Is the rudder trim on the panel tied to the KAP 150, or is that ran independently?

Asking because I’m looking to upgrade my autopilot.

[Fritz1]

I have a KFC225, took it out for repair and flew the plane home without it, elevator trim did not work, but rudder trim did, KAP150 most likely the same

[Fly Boomer]

13 hours ago, Fritz1 said:

I have a KFC225, took it out for repair and flew the plane home without it, elevator trim did not work

Do you mean the Manual Electric Trim (on yoke) did not work?

[LANCECASPER]

14 hours ago, warrenehc said:

Hello, new owner here.

Is the rudder trim on the panel tied to the KAP 150, or is that ran independently?

Asking because I’m looking to upgrade my autopilot.

Rudder Trim has no connection to any autopilot on a Mooney.

A Yaw Damper, if installed, would. 

[Fritz1]

Yes, electric joke elevator trim goes through the autopilot and is disabled when autopilot is un-installed, aircraft is legal to fly when correctly placarded

[PilotX]

Assuming you upgrade to the GFC500...rudder trim will fight the YD on the GFC500. Meaning if you turn on the AP in climb and then in cruise you don't disconnect the YD and center the ball again, the YD will (may) eventually disconnect the AP until you fix it, I have gotten to where I shut off the YD and just center the ball using rudder trim. 

[Marc_B]

@warrenehc to answer your question: Bravo rudder trim is independent of the KFC/Autopilot.  If you install the GFC500 with Yaw Damper, you should be able to leave the rudder trim in place.  However GFC500 pitch trim servo replaces your existing King electric pitch trim as that IS part of the autopilot.

 

Long body rudder trim has L brackets (#10 below) attached to the ends of the bell cranks. There’s a spring tensioned wire (#12/13/14 below) that’s attached to the brackets that’s wound around the rudder trim servo wheel (#4 below).  In these installs the Garmin YD on the GFC500 mounts differently and allows retention of the Mooney rudder trim.

However on a few midbody Mooneys (I.e. the Encore) Mooney used the S-Tec rudder trim/yaw damper that can add a YD and rudder trim to the aircraft but still functions independently from the KFC autopilot. Those are also installed in the same location that Garmin GFC500 YD is installed, so must be removed to install GFC500 with YD.

The interesting thing is that looking at a handful of IPCs for other midbodies including my own, and comparing to the Bravo for example…I think that the parts for the long bodies are same part numbers on the K and likely one could easily take a long body rudder trim and add it to the midbodies…if you had approval from Mooney to do so.

Of course you don’t really “need” rudder trim for smaller engine/lower HP Mooneys. Just saying it looks like rudder time appears somewhat universal among Mooneys out side of the S-tec YD/Rudder trim units.

[PilotX]

Mooney Bravo pilots who do a lot of takeoffs.

[dkkim73]

On 1/9/2025 at 8:15 AM, PilotX said:

Mooney Bravo pilots who do a lot of takeoffs.

Ah! A case of "182 leg"... 

I see the yaw damper mentioned in a lot of G1000 materials. With the Acclaim the lateral stability seems very good and I haven't felt its absence, but wondering if some people retrofit them? Might not even be possible given the type certification of the install. 

I'm still trying to figure out best use of rudder trim in my flow. I'm currently trimming only for long segments (eg cruise) and trying to develop the practice of using pedal force for anything shorter than a few minutes, for better awareness of flight dynamics and to prevent inadvertantly landing caddy wompus for no reason.  Eg working out engine out simulated settings yesterday (spurious probably due to cold air), stalls etc

 

[LANCECASPER]

21 hours ago, dkkim73 said:

Ah! A case of "182 leg"... 

I see the yaw damper mentioned in a lot of G1000 materials. With the Acclaim the lateral stability seems very good and I haven't felt its absence, but wondering if some people retrofit them? Might not even be possible given the type certification of the install. 

I'm still trying to figure out best use of rudder trim in my flow. I'm currently trimming only for long segments (eg cruise) and trying to develop the practice of using pedal force for anything shorter than a few minutes, for better awareness of flight dynamics and to prevent inadvertantly landing caddy wompus for no reason.  Eg working out engine out simulated settings yesterday (spurious probably due to cold air), stalls etc

 

I have never felt the need for a yaw damper either, but I also have never sat in the back seat during turbulence. I asked Garmin about it when I attended their class in August. By the the time two days were over they got back to me with the answer that the G1000/GFC700 installation for Mooneys does not have a yaw damper, which I knew, and cannot be added on, which is what I was curious about. That being said, it's still the best autopilot I've ever flown behind. .