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Electric Pitch Trim

n38139

Well Known Member
Anybody ever converted manual pitch trim to electric? All of my airplanes have had electric and the new one has manual.
 
If you do, don't forget to re balance the elevators, as that servo has a big impact on counterbalance weight.
Tom.
 
Trim servo stays in fuselage

If you do not want to rebuild your elevator to encompass the trim servo and then be concerned with balance, leave the electric trim servo in the fuselage. I helped do this with a friend. We had a short cable made which attaches to the existing trim tab in the same manner as the existing trim cable and through the same path once the manual trim cable is removed. We mounted the servo under the vertical stabilizer so the cable is just under two feet long.
 
There are a lot of posts on here about doing it. I have been considering it for a couple of years. Here are a couple of links. Some are for other models but they all work the same.

http://www.vansairforce.com/community/showthread.php?t=80198

http://www.vansairforce.com/community/showthread.php?t=75060

I thought I had saved some other links but can't find them now. There are several methods used. Some people mount the servo under the empannage fairing and run a new cable to the trim tab. One guy put the trim cable up under the panel to drive the normal manual trim cable. I think he had to modify the trim cable end. Check the drawings too. The control horn on the trim tab is larger for one application than the other. I don't remember which is larger. I think it was the electric trim setup but I read somewhere that people have done the conversion successfully without changing that control horn too.

I keep thinking about doing it but I have not felt like messing with the wiring. I am capable, just not enthused! Good luck and let us all know what you do and how it goes.
 
I actually put the trim servo in the cockpit in my RV-4 when I owned it and worked out really well. It had the trim lever kind of like a throttle lever except it was a little longer.

My new, old airplane has a long cable that has a vernier type knob on it.
 
I converted manual to electric in my RV7A

Last fall I removed the manual trim in my 7A and installed electric trim. Like "Skysailor" suggests here, I put the trim servo itself under the vertical stabilizer on the self located there. I reused part of the old manual cable instead of ordering a custom cable and so far it's working great.

At the same time as I did this swap out, I installed Tosten military style five button grips, and a trim controller board. I purchased the trim controller from Pat Hatch. A trim controller is required when more than one trim switch (I.e. Both grips) are installed.

I'm really glad I converted both my manual aileron and elevator trim systems to electric and swapped out my grips. Trimming the RV has always been easy but now it's truly a no brainer in that I'm just instinctively trimming off pressures. My greatest preinstallation concern was the electrical wiring changes and Pat Hatch graciously guided me via email throughout the process.

I strongly encourage you to contact Pat Hatch for a trim controller and Kevin at Tosten Mfg. They're both great people to work with.

One change I'm thinking about doing (to give me greater peace of mind) is going ahead and ordering from Aircraft Spruce a two foot custom cable to replace the old manual cable I modified. I'm not totally satisfied with my adaptation there.
 
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