Bill, I believe that the problem was resolved back a couple of years ago. I'm not sure what they did, I seem to recall that they either lowered the threshold voltage or reduced the re-boot time... or maybe both. A properly charged 4.8 volt pack of sufficient capacity should be just fine.

I just happen to like the response of the 6 volt packs so I stick with them, but I could easily use 4.8 volt packs... I'd use at least 1000 mah, though, but only to get the flight time and not for any concern about a re-cycle time for the receiver.

CGr.