Nash:
Originally posted by nashtm
But in full power verticals it pulls left some much that I need almost full right rudder. It also only has enough rudder to hold it in a knife edge with left rudder. Is using a mix on the radio a good solution ?
One last test. Full power level flight, chop the throttle. If you have an immediate right yaw, then yes. Crank some right thrust in. Everything else you say points to the need for it.
On a trainer type airplane I don't mind using thrust angles to correct design problems, as they lead to greater upright stablilty. But these same angles detract from an airplane's inverted capability. Keep this in mind.
If you aren't stuck on the plane being scale, you might consider a rebuild of the vertical fin and rudder - keep the same total area but increase the rudder to 60 or 65% of the total area, do the same with the horizontal stab and elevator.
There are two other possibilities. Strat mentioned one - horizontal balance. The other possibility is built in left thrust. Did you build the plane yourself? Are you sure the left and right fuselage sides weren't interchanged?
Do you have a thrust angle gauge? The Robart incidence meter will work. If you don't, find a straight yardstick and drill a hole at the 18" point. Bolt it on the engine and measure the distance to the leading edge at each end. Works very well.
Let us know what you find.
Bill.
PS: Mixes are nice for a lazy pilot, or one trying to get the utmost precision in flight. The very last thing to use in basic trimming. wr.