On a plane of this weight (F90, 68" Yak)I do not see any extra draw using digital servos(5625's) and a 5oz 6 volt 1800mah battery pack. I can get 7 to 8 flights on a full charge. Yes the digitals will draw a little more under no load, but it is the load that draws significant energy from the battery and there is not a lot of load from a 9-10 pound plane. Put the same radio equipment in a 17 pound plane and it will be a different story.