My timer has a differential gain feature that adds feedback gain when the system is loaded, as in a hard corner, so you get a bit of a boost. It cannot back-off on the down hills however, because it does not uses a position sensor of any kind. The only system readily available that can add rpm going up and back-off going down, is the one sold by Igor Burger that uses a 3-axis accelerometer with some fancy software.
The shut down feature is quite unique and triggers if the rpm suddenly goes below a certain percentage. This also depends on how much power the overall system has of course, so I would guess that in Fred's case his system was powerful enough to grind the prop without dropping much rpm. On take-off in long grass I recommend that the model be held back until the motor spins up and kicks into governor mode because it cannot shut down while it's spooling up.
If you have any more questions then just shout.
Keith R