Converting the Rans was distinctly easier than converting the Thruster, mainly because the FAA don't care about ultralights, bless 'em. This means that I get to do whatever I want to it, so I started out by making a list of what I needed the throttle to do:
  • open the throttle
  • close the throttle
  • stay where I leave it
  • allow me to control the plane at the same time
  • not interfere with the brakes

I thought about something like the throttle on the Thruster, but the stick is between my knees, rather than next to me, and my buggered wrist won't turn that far over. I'm lazy, so the easiest plan seems to be a twistgrip just thrown onto the stick.

I spoke to Vince, an Airframe and Powerplant engineer at Freedom Field about my idea of having the twistgrip turn the existing throttle tube, just in case a cable breaks, or somebody else wants to fly my plane. He machined up a couple of parts for me.

The friction on the standard throttle meant that I'd have to use a 2 cable throttle, so one cable pulls the throttle open, and one pulls it closed. Luckily, MotionPro make a dual cable system for 4 stroke dirt bikes, so I used one of those :o)

I then found out that it'd have to run up one side, to avoid the control stick itself... so I moved everything to run it all up the side. Doh.

I snipped the cables to length, and routed them along one side, so they don't interfere with the full and free movement of the stick. Then I put on a hand grip, cut so that the top doesn't rotate (allowing anybody else to not hold the twistgrip). I ran a push-to-talk switch up there for the radio.

I built up a single cable running through the unit, then poured some gas into the thing and started taxying around the airfield.

My instructor, Ray, did a low hop along the runway, then a single circuit. He pronounced it a good flier :o)