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Yaw Dampener and Aileron Trim

asw20c

Well Known Member
Over 500 hours into the project and I'm only just now realizing I should have been paying more attention to the resources on Van's website. To wit, the avionics update that came out in February of this year. In this notice there are a slew of subkits that Van's offers, or will offer when the kits are available and I have questions that some of you may be able to answer. First, I intend to install all Garmin products including auto pilot. I see among the list that there are yaw dampener and aileron trim kits. Just from the title it sounds like that would be in addition to pitch and roll. Are these kits necessary? It sounds like they are more nice to have rather than need to have if installing a 2-axis autopilot system. In fact the yaw dampener sounds like it would turn this into a 3-axis system. The next question regards the GMU 22 magnetometer install. I've seen several posts on this website where people have complained of interference with the magnetometer due to the nearby high current wiring for a heated pitot. This seems nuts to me that if this is a known problem why the magnetometer mount is not designed for the right wing. Or is it? I have no way to know whether it would fit equally well in the right wing. Can anyone address this too?
I have tried to be as vigilant as I can to make sure I address all of the things that I want to include in my plane while it is still easy to install. The service bulletin for the inboard aileron hinge is a prime example. Easy peasy to install now, but a HUGE pain if trying to install it later in the build or after flying. So far I have found the plans to be excellent, but the one glaring omission (at least from my perspective) is some discussion or notes in the plans that might say something to the effect of 'if you intend to install x capability, now is the time to do it.' For some of you repeat offenders it might be obvious, but to me it isn't. My biggest fear is to realize at some point in the build that to install some capability that I'll have to undo part of the build to have access to where it is to be installed simply because I didn't know when to do it. I can't be the only one with these sorts of questions.
Thanks for any feedback.
 
I've gotten some help in this regard from my EAA Tech Counselor (who is affiliated with Van's) but it would be nice to have some resources as you describe - in my mind a community of RV-14 builders can be very helpful in this regard. I've also done some calls with Stein Air (ordered fuselage wiring harness from them also) which helps with some general guidance - for example after our discussion of my intended panel (G3X, IFR navigator, etc) they terminated the harness which should make the final panel wiring more of a plug and play operation.

One thing that's a bit confusing for me is what comes with the kits versus what I need to buy "extra". I've ordered LED lighting options for empennage and QB wings, but from there I'll have to feel my way along.

I also ordered Vans flap positioning kit, as I will be getting to the flap motor install soon. Regarding aileron trim and yaw damper - still trying to figure out both the "when" and the "if". I've looked at the install for the yaw damper (attaches to rudder cables) and it looks complex enough that I think I'll pass on it: not because I'm spooked by the install, but more concerned about serviceability/reliability.
 
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The Garmin pitch and roll kits you want to buy. Not just for the brackets that fit existing holes in your build but they come with all the hardware to make the pushrods between the servos and the larger control rods. plus you get wire harnesses connectors that plug right into the wing harness (comes in wing kit) and the fuselage harness that comes in the tailcone (empennage kit). If you want aileron trim, buy that kit too and add as you finish up the wing kit. The GMU22 magnetometer goes in the left wing bracket that is part of the wing kit, it is made for the left side and there are holes in the bottom skin of the left wing specifically for this bracket. What you need to buy is the GMU22 mounting kit from Vans that holds your GMU22 and allows it to clip into the left wing bracket. Wire routing planning with the magnetometer in mind during assembly should keep you safe, probably the only problematic item would be a heated pitot so keep those wires as far away as possible.
 
After flying my RV-14 for about 75 hours I'm glad I didn't waste money and effort on aileron trim. I don't think I would have used it once.
Maybe rudder trim would be nice on climb but once I settle down into cruise the plane is very balanced with my feet of the pedals.
I imagine that because of the quality of the 14 kit and plans, most of us will get the same result. There just aren't the variables that other models have to cause balance issues.
 
After 95 hours, I've found the aileron trim very useful. So does the autopilot.

I have a G3x system and as fuel burns off in one tank I can see the autopilot adding trim as needed. When switching tanks every thirty minutes the trim cycles back and force enough to notice.

I've flown it hands off trimmed up and within 30 minutes there is a small but noticeable out of trim condition because of the fuel imbalance. It is small and easy to hand fly but it's nice to null it out with aileron trim. I recommend it.

I didn't go for the yaw damper but for the price of a fully tricked out airplane it's cost is not outrageous. Only one airplane unit!

That said, I already fly >95% of the time in the 14 with my feet on the floor so you don't really need it.
 
After 95 hours, I've found the aileron trim very useful. So does the autopilot.

I have a G3x system and as fuel burns off in one tank I can see the autopilot adding trim as needed. When switching tanks every thirty minutes the trim cycles back and force enough to notice.

I've flown it hands off trimmed up and within 30 minutes there is a small but noticeable out of trim condition because of the fuel imbalance. It is small and easy to hand fly but it's nice to null it out with aileron trim. I recommend it.

I didn't go for the yaw damper but for the price of a fully tricked out airplane it's cost is not outrageous. Only one airplane unit!

That said, I already fly >95% of the time in the 14 with my feet on the floor so you don't really need it.

When do you recommend installing the aileron trim?
 
I concur with Bob Meyers. I have 140 hours and use aileron trim routinely, not just accommodating fuel burn but also solo vs with passenger. I did not do a yaw damper and don?t miss it. Roll trim installs on an inspection panel - I did it after the wing was completed but it would be easier to do certain elements with the bottom skin off.
 
When do you recommend installing the aileron trim?

You need the aileron pushrod at the final neutral location because you need to measure the centerline off the trim servo onto the pushrod them measure and install the brackets and springs. I think the best time is when you are adjusting the pushrod and aileron for neutral. I set my aileron neutral right after riveting on the bottom skin. Set the neutral, mark and remove pushrod for the brackets, rivet and install springs and reinstall.
 
I just found out that there is no manual trim provided so I guess electric trim is the only way available.
Does anyone know how many trim indicator is available on the G3X? I know at least two but I can't remember if that is for flap and trim or two for trim and one for flap.
If only two, then I would need to get an external trim indicator
 
When do you recommend installing the aileron trim?

I would have liked to do it as one of the last steps of wing construction, just after setting the aileron push rods to neutral - as suggested by another poster.

I didn't do it until the plane was near completion with the wings attached and the plane sitting on its gear. That was not fun.

I had not realized how much you have to pull on the springs to set them in place. It would be a lot easier with wings on a bench or in a wing stand.
 
I would have liked to do it as one of the last steps of wing construction, just after setting the aileron push rods to neutral - as suggested by another poster.

I didn't do it until the plane was near completion with the wings attached and the plane sitting on its gear. That was not fun.

I had not realized how much you have to pull on the springs to set them in place. It would be a lot easier with wings on a bench or in a wing stand.

This is very helpful - I have QB wings on the way.
 
I think I'm at about 165 hours on the -14 now. I have Aileron trim and use it quite a bit. Inevitably whichever seat I'm in, which changes from day to day, requires the pilot to trim to the opposite side, and it's made worse if the fuel loading is higher on my side. Yes, if all you do is fly around your locale, and you most often fly alone, you probably won't miss it, but, if you fly long x/c trips, or switch seats, or add/remove chubby co-pilots, you will definitely find you will occasionally use it. In looking at my panel indicator, I often see the trim cranked within 1 bar of either side limit, so I know it's definitely getting used.

I don't have a Yaw Damper but to be honest, don't know what I'm missing. There are times it may be nice to see, but I've never flown an RV with one, so for now, ignorance is bliss.
 
I would have liked to do it as one of the last steps of wing construction, just after setting the aileron push rods to neutral - as suggested by another poster.

Correct me if I am wrong but wouldn't setting the aileron push rod to the neutral position involves attaching the push rod to the stick so the stick is also at the neutral/vertical position? How can that be done with the wings not attached. This is of course unless the basic measurements that Vans gives is used as a guide.
 
Correct me if I am wrong but wouldn't setting the aileron push rod to the neutral position involves attaching the push rod to the stick so the stick is also at the neutral/vertical position? How can that be done with the wings not attached. This is of course unless the basic measurements that Vans gives is used as a guide.

There is a jig that holds the aileron bellcrank at the proper angle for neutral. Adjust the pushrod so the angle is set there and also at the wing root. Now the wing is completed as far as that pushrod being properly adjusted and you can then remove and install the aileron trim setup. The control column stick is a separate adjustment made later.
 
Correct me if I am wrong but wouldn't setting the aileron push rod to the neutral position involves attaching the push rod to the stick so the stick is also at the neutral/vertical position?

What Chris said,

The jig is easy to use and all the wing rigging can be accomplished off the plane. When I attached my wing, I just confirmed the aileron was positioned correctly after attaching the wing, and then did the stick adjustment.

No changes were made to the aileron push rods while on the plane. They worked perfectly as set off the plane.
 
Thank you Bob and Chris for chiming in. I did have a jig for my RV7 to set the aileron neutral position but when you attach it to the stick, there are other [fine] adjustments that need to be done on the pushrod so your stick is also in the correct position.

I am still ways to get there but the more I learn the more prepared I will be.
 
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