RE: receiver battery
Thought I would put in My 2 cents worth, I had - "had being the keyword" a nice 40 spitfire, new battery etc.. fully charged , feild checked voltage prior to flight -took off, put retracts up and made a couple of turns, landed. Went up about 2 minutes later and put retracts up, on the third full circle coming out of a dive, it started a slow porpous with full throws up and down, no throttle response, I gave it a little up elevator, nothing- Lawn Dart-
Moral of the story is to check the flimsy wire made retracts when you land, they tend to bend a little and won't retract fully and will drain your battery very quickly.
On the other note :
As the others have stated - check your batteries and ALWAYS pre charge before flying! Cheaper that way but you never know what can happen........