I'm pretty new to flying, I have a sig kadet with a glow engine but bought the Crazy max to fly in my front yard ( I have a horse paddock across the road)

I'm having a hard time getting this thing in the air, I have to do a hand lunch because the ground is to rough. My main problem is I climb to about 15 - 20 feet and the plane sem to bank and gather speed. The problem is I can't seem to get it out of the dive and we come in for a very rough landing. I'm back to the drawing board with my epoxy to patch it up gain and try once more. I have zero wind so is this just a classic case of stalling and then things going bad real fast.

The major problem is the is all over in 60 seconds so trim ajustment is the last thing on my mind!!... It feels like the plane is under powered, I was think of getting a 400 speed motor and cutting the fusalage behind the wing and making a foam front section to the plane or does this sound like a bad idea??