IMHO balancing with 1/2 tank of fuel is asking for trouble.
i've just read the report and they also say it's tail heavy, and they have an 80 4 stroke and 2700mah pack up front?? so no way the 46fx is going to add enought weight.

theres another report of an elec conversion at e-zone
http://www.ezonemag.com/articles/2003/feb/cub/cub.shtml

they also had CG trouble and had to cut a hole in the fire wall to shove the 16 cells further forward.


a couple of things

mont the engine as far forward as possible
get a good heavy spinner
mount the battery on the fire wall in the engine bay.
add the lead under the engine mount as far forward as possible