I just saw this thread. My father and I built this one back in the late '70's and he still has it. We had a .25 glow on it and was plenty of power. I would leave it as a rudder only. It may seem a litle squirley, but we did learn to fly succesfully on it with the radios of the day. As far as a battery, with the 12x4.5 prop, U R going to need a 3S. If FT states that motor will pull a 3lb bird, then a 3300mah should fit in there without any problem. If U R concerned about the weight, then U could go to a 2200mah. Hmmm... my dad still has his in the attic, Now I'm thinking of pulling it down and doing a convert on it.