ORIGINAL: BMatthews
MTK, if I read your post right the idea is to select a CG that makes all the other stuff work better and then size the tail such that the TVC results in a neutral point very near to 25% to achieve near neutral handling in pitch as well as yaw and the other things. Is this assumption right?
BMatthews,
The first part of your question, yes.... choose a CG no greater than 30% MAC, and lower is a little better. I don't go any further fore than 25%MAC, however, on my aerobatic models. A little further fore is tolerated better by trainers.
All of today's pattern models can tolerate CG as far aft as 40% MAC but they won't fly a pure envelope with that far aft a CG.
The second part of the question, no. The neutral point will be aft of the CG and you will need some push on inverted flight, assuming you trim for hands off upright flight.
A lower TVC places more load on the wing as does a fore CG. A lower TVC will reduce pitch stability, allowing smaller elevators and making smaller pitch commands more effective. This will result in a more lively, agile aerobatic model. Lower TVC enhances at least the two bugaboo maneuver categories in aerobatic circles: snaps and spins
Again, great for aerobats but not so great for trainers. Trainers should sport high pitch stability and high TVC.