RE: Rabbit problems
I would have to see it... that does not sound normal. I have quite a bit of time on the brand/ECU and the only time there is erratic/erroneous RPM is:
1) ECU battery not plugged in
2) Momentarily when voltage is being applied to the burner and the starter motor has not begun. ("Burner On" phase)
Besides those two scenerios - the RPM readings should be rock solid. Digital servos or not.
The other thing is, I wouldn't second guess the wiring and circuitry of the unit. Rest assured that the people that have designed the motor and the ECU are very experienced as they are directly the pioneers in the hobby of micro turbines. If there needed to be a capacitor in the line - they would've put it there - and YES, they probably have thought of everything. Now, am I saying that these things don't malfunction... NO! Sometimes they do. Again, a video would be helpful and I would do extensive ground runs at all throttle settings before flying that overweight airplane with this questionable condition.