View Full Version : Electric Trim

Jim Miller
01-08-2011, 02:22 PM
After seeing Bill's trim system I abandoned the trim tab idea and built a similar system.
I have finally got it perfected after correcting a interference with the upper elevator
cable and I custom made the jackscrew and Yoke. An other idea gained from this site
was adding a turnbuckle to the elevator balance cable. I kept reducing the length
of the alum standoff's holding the motor and in the end added a cable quide. The 4130
Yoke weighs less than 3 oz more than the alum, cost 10 bucks to make and overall
the system is much lighter than the trim cable system. I will try to post a photo.

Jim Miller

01-08-2011, 03:40 PM
Nice...would love to see more pictures...would like to do this to my exp...

01-08-2011, 04:38 PM
I have a similar system on my cub, it works well.
I am planning on replacing it with the stock system, as I am going to remove the electrical system.

Sent from my HTC Evo using Tapatalk

01-08-2011, 07:11 PM
Looking good Jim

Jim Miller
01-09-2011, 07:39 AM
Nice...would love to see more pictures...would like to do this to my exp...

I will try to post a couple more photo's.


Jim Miller
01-09-2011, 07:45 AM

Here are a couple more photo's. Making the Steel Yoke was a last minute decision. I had ordered a Yoke from Turbine
Cubs. It looked fantastic but they didn't use the standard Piper Jackscrew thread (5/8 6TPI) so I had to send it
back and gave making one a try.


ron cope
02-19-2011, 04:35 PM
Where did you buy the trim motor and about how much. I like the looks of your set up. Thanks .

Jim Miller
02-20-2011, 08:33 AM
I bought it from Mcmaster-Carr #6409K18 $37.42. If you have any need for more info you can give me a call. Initially was planning on using a elevator trim tab with fixed horz and added a couple of thru-tube bushings which turned out to be very handy for this new system. I made the motor to jackscrew coupler on my mill/lathe. The upper
elevator cable was too close so I added a cable quide on one of the motor attach bolts which took this problem out of the picture. I will PM you my phone number.

Jim Miller

02-20-2011, 11:07 AM

Are going to install a trim indicator? If so Electric or manual?

Jim Miller
02-20-2011, 12:24 PM
I ran a extra wire and plan to use it to turn on a light when trim is zeroed out for takeoff. I haven't worked out the
details yet on how to connect a switch to yoke.

02-21-2011, 08:31 PM
I have thought of using a gas tank fuel level sending unit coulpled to a gas level gauge as a trim indicatior. Anyone tried such a setup?

Jim Miller
02-22-2011, 07:01 AM
That's a good idea. Most fuel gauges seem slow to respond, maybe use the sending unit and just a radio shack
panel amp meter. You could use shunt resistors to give the proper meter deflection. On my light-on for take- off trim
I am going to attach a Thin "bumper" on the yoke and a micro switch that will be turned on to pick up a ground
for a panel light. As a move the trim the light will blink-on to show I have just come to the desired position.

02-22-2011, 11:03 AM
This article in Nov. 2010 Sport Aviation is pretty much how I'm doing it.
Flap Position Indicator (http://www.sportaviationonline.org/sportaviation/201011/#pg80)