What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Yaw, trim tab and auto pilot.

Tbarsic

Member
Hello, everyone long time lurker new to posting.
I just picked up a nearly finished RV 10 empennage kit from a fellow Vans owner. I am checking over the work and diving into the instructions. So far the work is excellent.

I am trying to plan out what mods I was going to accomplish for the empennage. When it comes to rudder trim, yaw dampener and autopilot I am slightly confused. Can all three be utilized? Is the rudder trim really required with an autopilot? I am thinking of just autopilot servos and yaw servo. Do I need to decide on avionics now before I get the autopilot servo and yaw dampener?

I am convinced I will do with an autopilot and yaw dampener but not sure about the trim tab.

Thanks
 
Yaw Damper would be part of your autopilot if you decide to go that way. Plenty of opinions if it is truly necessary or not. This is NOT a replacement for a trim tab (fixed) or a rudder trim system even if some people use it that way sometimes.

Honestly, no absolute need to make decisions on what you want to do at this point in the build. Easy enough (with a little effort) to install a Yaw damper or trim later in the build. Decisions on Dynon or Garmin may impact what you install or if new avionics are released in the future. For rudder trim, there are some examples of electronic trim tabs, bolt-on manual systems (Aerosport), or just a wedge installed on the rudder. All work and are being flow.
 
The yaw damper definitely helps in turbulence .. calms things right down .. quite nice!

I would definitely install all the bracket kits, and then choose later what servos to install.

If you're having a wiring harness built by SteinAir ask them to pre-wire for everything, it won't add much to the cost.

It's a lot easier to do it now than later .. I installed my yaw servo at 150 hours and while certainly doable, If I had a time machine I wouldn't hesitate going back and install the brackets when I had the chance, butterflies be damned :D
 
I appreciate the feedback. I am thinking now that the autopilot will do yaw damper duties, correct?

Is it better or easier for the autopilot to have trimmed aircraft? If that is the case then I will need to install trim tab and servo for yaw then the servo for autopilot and no servo for yaw damping.
 
Yaw Damper != Trim

I am thinking now that the autopilot will do yaw damper duties, correct?

Yep, controlled by the autopilot, the yaw damper does just what it says .. takes the bite out of sudden yaw movements .. the overall effect is a calmer airplane when you're getting kicked around by turbulence .. while it does help trim on long flights with wind pushing you around, it won't do a great job of trimming an out of trim airplane.

Is it better or easier for the autopilot to have trimmed aircraft?

Yep.

I think it's safe to say that it's completely normal to have to adjust with some kind of rudder trim, but you won't know until you're well into your phase 1.
 
Last edited:
I appreciate the feedback. I am thinking now that the autopilot will do yaw damper duties, correct?

Is it better or easier for the autopilot to have trimmed aircraft? If that is the case then I will need to install trim tab and servo for yaw then the servo for autopilot and no servo for yaw damping.

Ok, I think something is getting lost here.
Autopilot can control 1, 2, or 3 axis. Pitch, Roll, and Yaw. Most typically do 2-axis, but if you want to you can also install the Yaw control (Also called a Yaw Damper).

This is all distinct from trim control. While an autopilot can correct for an out of trim condition, it's not the best practice. Yes, you will want to install a rudder (or Yaw) trim.
 
My thoughts are well known on this subject -- rudder trim-yes (number of ways to the skin the cat both fixed and adjustable--I use the Aerosport spring bias system), yaw damper - no.
 
Last edited:
I appreciate the feedback. I am thinking now that the autopilot will do yaw damper duties, correct?

Is it better or easier for the autopilot to have trimmed aircraft? If that is the case then I will need to install trim tab and servo for yaw then the servo for autopilot and no servo for yaw damping.

The next question will be: "Which auto pilot?" For years Tru Trak had the duties with the G900X, but if you go Garmin with the G3X you will get to use the Garmin autopilot, which in my humble opinion is Way better!

-Marc
 
My thoughts are well known on this subject -- rudder trim-yes (I use the Aerosport spring bias system), yaw damper - no.

Auburntsts, how well does the Aerosport spring system integrate with an autopilot? I want to avoid excessive work for the autopilot servo. I don't want the two systems to fight each other.
 
Auburntsts, how well does the Aerosport spring system integrate with an autopilot? I want to avoid excessive work for the autopilot servo. I don't want the two systems to fight each other.

It doesn't integrate as far as I know being a simple mechanical system. I only have a 2-axis autopilot so it's a non-issue for me. I'm blissfully ignorant as to how to integrate it into a 3-axis system.
 
Auburntsts, how well does the Aerosport spring system integrate with an autopilot? I want to avoid excessive work for the autopilot servo. I don't want the two systems to fight each other.

Most autopilots can only supply a limited amount of force. e.g.,if the airplane is way out of trim, especially in pitch, the autopilot may disconnect (as its maximum torque cannot correct a deviation). Virtually all low cost 3 axis autopilots call the third axis a ?yaw damper? because that?s what they do. While they can supply a small, constant offset for an out of trim condition they are limited in how much and how well they do that. Now, my opinion: I have a -10 with a fixed wedge on the rudder, which keeps the ball centered thru all the cruise speeds I routinely use. I have no yaw damper, nor do I contemplate getting one. I?ve never had a back seat passenger turn green or get sick (if I had, I might feel differently). I have a Trio Pro 2 axis autopilot with auto trim in the pitch axis. Works great, either stand-alone, or, usually, controlled by my GRT Hx EFIS. If you intend to shoot approaches with the autopilot the auto-trim is a nice option to have in the -10, where out of trim pitch forces are higher than the two seat RVs.
 
Yaw , yes please

I have been flying my RV-10 for 600+ hrs and have the wedge and Aerosport Rudder Trim,we get along fine.

On a customers recently completed RV-10 (VH-BKK) we installed the full Dynon/Aviydne kit with Yaw Dampner and all I can say is WOW what a difference.

It is pointless asking the front seat pilots and co-pilots if you need a Yaw Dampner , They sit on the centre spar, instead ask the rear passengers ,especially children and non flying public and they will all say YES please.

I have added it to my future Dynon upgrade list.
 
From Dynon Documentation

?An added benefit to rudder control is that it automatically coordinates turns and provides rudder trim. The Yaw Damper subsystem of the autopilot combines these two features.? p.8-7, Skyview Classic Pilot?s User Guide
 
Yaw damper

The RV-10 is pretty much a feet on the floor aircraft except in take off and landing. Landing in a cross wind needs no explanation. Take off needs a big stab of rudder to counter while bringing the power in.

Cruise, I have found a substantial amount of tail wagging (as compared to a 182), helped a little by holding firm on both rudder pedals. I will probably add the yaw control to the autopilot in the future for rear seat passenger comfort.

The auto trim feature of the G3X system works by looping the electric trim power wires thru the respective servos. The servos trim off the torque of the servo by automatically powering the trim tabs. This feature will not work with manual trim systems, only powered.

As an added comment on whatever trim system you decide on, the RV-10 pitch trim at full speed is too touchy for cruise. So speed scheduling is a must in my opinion. If you use a VPX ECB system that feature is available as a step function at a pre-set speed. You can only access the set up in configuration mode with a laptop plugged into the ethernet cord. If you also have the G3X the trim can also run through that system. The G3X settings adjust trim speed over a preset reduction range (rather than a step function) with the access to adjust settings accessible through the PFD configuration page. My opinion is the G3X is better and more accessible.

Good luck on your build.
 
As an added comment on whatever trim system you decide on, the RV-10 pitch trim at full speed is too touchy for cruise. So speed scheduling is a must in my opinion. .

Trio Pro with autotrim also has programable speeds. Can also be used manually with servos disengaged.
 
Back
Top