I had an early FUt pcm set (8SGA), and with 4.8V rx packs, the response was not
exactly crisp, to say the least. I put a 6v pack in and it was Good!. It turned
out that these early pcm rxs were higher current drain than usual, so 6v was
recommended fix. I now have a 9VAP, and on 4.8v rx the response if fine, so
I am not going to bother with the 6v packs anymore ( I do use 700mah packs tho).As for getting the fail safe to work, one of our members makes a gizmo that goes
between the rx and any servo of your choice, and when the pack gets to 4.4V
(for a 4.8) it puts a 15-20degree waggle in the signal - throttle or rudder is
probably safest here. Obviously he can make it to go off at any voltage desired.