RE: Some Questions
NiCd or NiMH? A NiCd battery looses about 20% of it's charge in a month so a 4.8v receiver pack goes to 3.8v by the end of the month. A NiMH is supposed to discharge faster. - Why don't you just charge it before you fly?
What counts as a flight? - Anytime the wheels leave the ground. [sm=biggrin.gif]
And yes, the elevated tank is a smoking gun for your hydro-locking.