[BrianG]

R/C LVCs are set up to output a series of pulses to emulate neutral/min throttle when they trip. For aircraft, that's 1ms pulses, for cars, that's 1.5ms pulses. I've never looked too deep into LVC circuitry, but it probably has everything on one IC (measuring circuit, firmware, and oscillator), so tapping into it to use a relay may not work.

Just remember that whatever circuit you use to function as an LVC will draw power itself (albeit small). So, you'd have to make sure that when it trips, it cuts power going to the load AND itself.