Chris,
Your statement that you flew until your receiver was getting low, about 12 flights, really concerns me. Most radios come with the standard 600 mAh battery pack. As a general rule, 4 or 5 flights at 10 to 15 minutes each will put that receiver pack out of business until it's been recharged. A dead receiver pack will ALWAYS equal a dead airplane.
I teach my students that if they cannot check the voltage of their battery pack with an expanded scale voltmeter, that they should quit flying after a maximum of (4) 10 minute flights. None have ever lost their plane from a dead battery using this limit.
I am only saying this as a suggestion since you have posted in the beginners column. I would much rather see you keep your plane for a very long time than to see you lose it early to a dead battery.
Thanks for the tip. I was checking my receiver battery with a tester that has about 10 LED's(green yellow red). One of the guys in the club was helping me out. I was taking short flights about 5 minutes, I was worried about running out of fuel. I don't know how long the the fuel will last with this engine.
I charge my batteries with a Supernova 250s charger and they usually charge over 700mAh if I don't push them too hard. I guess I got lucky with these batteries that can hold a little more. I also picked up some AA nimh to make a flat pack to fit under the control rods in the tail to balance it better. The battery pack I have now is square and doesn't fit.
Chris