RV-12: Aileron Trim

Having just passed 200 hours on the -12 I decided it was time to come up with an aileron trim. I do not have the auto pilot so I needed to be able to trim the plane for passengers, fuel burn, and when I have a big lunch.

Sorry the pictures turned out black and white.



I made this bracket for the Ray Allen servo to get the actuator over the lightening hole for ease of installation to the bely pan of the -12.



I drilled out the 14th & 15th rivet in the rivet line under the pilot's seat and used those holes to re-rivet the bracket to the belly pan. Removing the wing would have made it easier I think, but no one was around to help.



Next I mounted the servo to the floor. In this pic I have not drilled it yet, just showing the location. I ran a bungie cord over to the aileron tube to gently pull it when the trim servo is actuated. After a few test flights it works good. Do not need much trim input so I may use a weaker spring like the Vans aileron trim kit comes with. Certainly does not take much pressure.

I mounted the Ray Allen rocker switch just forward of the flap handle on the seat pan. I may move it to the panel under the elevator trim, but for now it is what it is.

I used a 1 amp breaker for power using the cig lighter. A 4 pin connector was used so that the seat pan can be removed.

YES!!!

Larry, this may be the most useful RV-12 Mod yet! 43WM is trimmed to level with me and about half fuel. Any departure from that means holding constant (very light!) pressure on the stick. Do you have more photos showing ho to servo is connected to the aileron tube (I can't figure out what the second photo is showing) or even some drawings? Something simple and relatively fool proof ( I fall into both categories) is EXACTLY way the -12 needs.

THANKS!

Wayne 120241/142WM

Depending on which way the plane tends to roll goverens which direction the tube needs to be moved. I simply wrapped the bungie to the tube and wire tied it. If you need to pull it the other way then wrap the bungie over the flaperon actuator tube. Crude, but it works good. I need to come up with a pulley to transfer the energy rather than have it slide over the tube.

Hard to explain, but if you look under the seat you can get an idea of what needs to happen. Just a little force on the tube goes a long way. I was amazed at what little force changes the roll. I wanted to just work on the pilots side so that there would be no possibility of interference with the stabilator cables. That would not be good.

picture of installed servo

Larry
Great mod . Could you post a picture or 2 of the servo and hookup.
I would like to install ON MY 12 ALSO. I AM INSTALLING A JABIRU 3300 AND WILL need it to compensate for the increased power. Thanks! Oren

With such light input needed, would not a manual actuator with cable be simpler to install? (I am using such system on the Allegro for pitch trim and it works great although the cable has to travel all the way back to the H Stab). You probably thought about it so I am curious to get your rationale for the electric frim. Not in any way intended at criticism

orenjr said:

Larry
Great mod . Could you post a picture or 2 of the servo and hookup.
I would like to install ON MY 12 ALSO. I AM INSTALLING A JABIRU 3300 AND WILL need it to compensate for the increased power. Thanks! Oren

Click to expand...

Wouldn't you want a rudder trim instead?

Dave

One-way?

Larry,

From what I can see, the servo can only pull, not push? I assume you have it set up so as the right side get lighter (no pax or fuel burned off) you can pull the stick to the right?

Wayne