The name suggests that you can fly your Kitfox by wire, and you can, and do it quite cheaply. What you need is 3 axis trim tabs to control roll, pitch and yaw. This idea is not an autopilot, but that it can be added later, and also quite inexpensively.

What I am suggesting is the use of R/C servos which can control trim tab position precisely. I think most readers do not realize how simple this can be. Starting in the mid 90's I installed servos on all 3 axis of my Model 2. They worked very well and he aircraft could be trimmed hands-off at any speed. I went on to develop my own autopilot, which worked and was successful in that it would maintain GPS altitude and heading. Several iterations were tried over the years, but I was always behind development technologies. Works perfectly in calm air but lagged a little when the going gets rough in turbulence.

So: WHAT DO YOU NEED?

1: You need 3 or 4 servos, dependant on whether you want one on both ailerons or just one. There are hundreds of suitable servos available, source at your local R/C shop or browse listings here. Cost $20.00 - $60.00 for each axis or I have had good luck with even less expensive.

https://hobbyking.com/en_us/turnigy-...asc=1985125349
https://hobbyking.com/en_us/turnigyt...asc=5982608624

2: You need a controller for each Axis. Your local R/C shop should have servo testers which will work or you could try one of these. Approx $20.00 each axis

https://hobbyking.com/en_us/turnigy-...asc=9144583950
https://hobbyking.com/en_us/hobbykin...asc=3606071541

3: You need a 5 - 6 volt power supply for the servos, this will run off your aircraft 12-14 volt aircraft power.
https://hobbyking.com/en_us/turnigy-...asc=7484766100.
Again a $20.00 item and you only need one for all the servos. An alternate option here would be a USB power supply.

The mounting of the servos can be a big challenge especially after the a/c is covered, I can provide photos of several solutions if there is any interest. My model 5 has the servos all built in before covering. You could also start with one Axis trim control and add more if you like what is happening.

Aircraftautomation.com has servo trim tabs, servos and controller available which could be an easy route to follow. After many years of developing my own system I have ordered their autopilot which will be an easy conversion for me. A 5% discount is available at aircraftautomation.com by using code " JIMCORNER10 "