Gentlemen.....Lots of good..well made points.....so where do we go from here...I agree whole heartedly that my primary reason for flying is pure enjoyment....probably like most folks...so the door is wide open for whatever amount of knowledge one wants to absorb.....I personally want to learn as much about airplanes and aerodynamics as possible...I still am at awe watching a 747 or 777 T/O as I see it everyday.....just like watching one of our models fly......back to CG....A P-40 (Realtively small tail surfaces) flys just as nice as a P-47(relatively big tail surfaces) if time is taken to balance properly "and" ensure surface travels are correct one must assume both are built straight and have proper wing washout, etc......what I'm trying to say its a matter of personal choice how much knowledge one possesses...and if directions are followed and good help is obtained at the flying field not much knowledge of aerodynamics is required....afterall its only a hobby.....either way works..its just a matter of personal choice....Bill....