Well since Terry is MIA I'll answer the 7.4v stuff. They make a 7.4v ignition. it's stamped on the back use 7.4v only. Terry gave me the go ahead to use a123 batteries on them too. I did have to open the high needle just a tiny bit on the very next flight. Either the ignition is hotter on the a123 cell or atmospheric pressures were way different that day.