asraox,

It sounds to me like the swirling prop wash is pushing your fin to the right, which steers the plane to the left. This problem is most evident when the airspeed is low, and the throttle is wide open. In these conditions, the prop is generating lots of swirl in the prop wash, and the airspeed is so low that the fin does not have a stabilizing effect. I have this same problem with a somewhat over-powered Goldberg Eagle. One thing that would help is to add some fin area below the thrust line. You may not be able to add enough to make a noticeable difference without dragging the tail on take-offs and landings. You can also practice giving lots of left rudder at the beginning of your takeoff run, and gradually easing off as you get some airspeed ( by airspeed, I mean speed relative to the air, even though the plane may still be on the ground ). This is what experienced pilots do without having to think too much about it. Another thing you can do is to gradually ramp up the throttle as you takeoff. This lets the amount of swirl build up at the same time the airspeed is building up, so you don't get such a large steering force from the propwash until you have some airspeed to help keep the plane straight. My favorite copout, which my instructor did not like, is to simply takeoff directly away from the pits, ignoring the runway, at full throttle, so the plane could happily steer to the left for the 15 feet that it takes my Eagle to get airborne. This, of course, is not appropriate if other pilots are expecting you to be taking off in the more conventional pattern. By the time you are in the air, you should be fine, unless you are still over-correcting with the rudder. One other possible help would be a prop with lower pitch.

Good luck,

banktoturn