RE: tf dc3
Peter,
I did take a quick look at that type of unit. However, I opted to go for a radio that has two throttle curves for airplane use (JR9503). I was tempted to just go and sync the engines on the high and low ends, but kept reading about how it is better to keep them in sync through the entire throttle range. So I looked at a couple of options.
Since I wanted to get a 2.4 radio any way, I picked the more expensive option of a radio which had twin throttle curves. I think the setup will be fine using a tachometer and 5-point throttle curves to keep the engines within a couple hundred RPM. You set it up like old-school helicopter throttle/pitch curves.
Also, the twin sync needs to have a magnet and sensor. You would need to run some type of back plate behind the props to mount the magnet (just like on helicopters with governor magnets on the cooling fan)… I don’t know how that would work on props with no spinners. However, I did not read through all 36 pages of comments on that unit, there may be options for reading the back plate of the engine.