RE: Is it my ignition or engine?
I was just breaking in a new gas engine today on my test stand. I ran the ignition unit off of a 4.8v 2000mah pack for a little over 2 hours and it still had plenty of power left in the pack. So unless you have one of the old style ignition units, you'll be able to fly for quite a while off of a 4.8v 2000mah pack.