Originally Posted by ppilotmike
Are you planning to install the spring bias rudder trim system?
Nope I added an integral trim tab while building the rudder, following much of what Brian Steeves did on his (link here
). It runs off a Ray Allen servo inside the rudder, and will be connected to the GSA28 AP servo in very much the same way as the other two axes. I think Garmin's built-in auto trim is brilliant, in that it minimizes the load on the servo by automagically trimming for neutral control pressures (other systems can do this too, but I believe the Garmin is the only one with it built-in).
By all accounts, the spring bias system works great as well, also many people add a piano hinge to the trailing edge of the rudder that is controlled by a servo (easier to retrofit) and that also works great. It all depends on how much time you want to spend, cost-wise I don't think any solution is monumental compared to the many other mods out there.
What got me convinced to add "something" was our local flying RV-10 builder/owner who added rudder trim to his after flying, which made me think it must have been important enough to take it out of commission for a while to make the mod. It seems several people on this forum have also discussed adding rudder trim after the fact as well, so it seemed important enough to spend some time on early on, and if you can integrate it while building the rudder, then why not?
As for the decision to add YD, that's sort of a different mission than the rudder trim. The way I view it, the rudder trim is to make my own life easier, keeping me from having to hold pedal pressure in different flight phases and speeds/configurations/etc; while the YD is to give passengers a more tolerable ride in turbulence by eliminating dutch roll and tail wag, which does seem to occur at least at slower speeds.
Finally, yes the cost of the Garmin YD install kit is extremely high, but with a little creativity you can build your own for a fraction of the cost. I used a reinforced Van's ADAHRS tray (that mounts next to the battery/elevator bellcrank) to mount the servo, and making a "boomerang" actuated by a pushrod from the servo that attaches to the rudder cables via some 18" cables and a home-made cable clamp. I did this by borrowing ideas from both drawings/photos of the Garmin kit, and also some photos of various builders' home-brew YD using TruTrak servos.
Mike Jimenez & Sarah Hammonds
EAA Chapter 33 Prez & Soc Chair
Marion, IA USA
RV-10 In progress! (N165MJ reserved)
-Emp & Wings complete
-Panel wired up, working on Fuse & Finish
-Blog horribly outdated (sorry)
-Too many distractions, we will finish the plane someday!!!