Let's see, where to start. First, about mesae's comment about me saying that "dihedral has little no [sic] effect on lateral stability." I never said that. Dihedral is the primary factor driving lateral stability. It however, has a very very small effect on longitudinal stability. My point is that aircraft designers have tools to create certain flying qualities. To create changes in lateral stability, dihedral is the primary tool. This does not really affect longitudinal stability however, because the dihedral angle is relatively small. If for some reason you go to extremely large dihedral, or anhedral angles, then the longitudinal stability could be affected. However, doing this would completely screw up the lateral stability. So much so, that it really becomes a moot point (I know it's redundant to call a forum dicussion moot).

Now, in terms of being production oriented. You're somewhat correct. I'm a modeler that also has a masters in aeronautical engineering and engineering experience. Does that mean I know more than someone with model experience? Not necessarily. But, I do know aircraft stability and control. Mesae, I think you need to reread my post about what the original question was, which is to make it possible to perform a flat turn without mixing. There is only one way to do this, and that is to reduce the the derivative c_l_beta to zero. This is what you could call yaw-roll coupling or dihedral effect. It is also known as the lateral stability parameter. If you reduce the dihedral effect to zero, then your goal is to reduce the lateral stabiltiy of the aircraft to zero. PERIOD. END OF DISCUSSION. If you disagree with that statement then you need to consult some more books.

Now, with that said, all I was saying is that one should be careful in attempting this otherwise you could get crappy flying qualities. I agree with you guys that model aircraft can be flown far outside the range of normal aircraft. At the same time, I often hear things from other r/c pilots like "Why do you waste your time with all that theoretical analysis crap. My plane flies just fine". Well the only reason your plane flies fine is because in r/c aircraft, the high power-to-weight ratio and huge control power can make up for really awful design. In other words, when you have excessive power-to-weight, an aircraft with horrible flying qualities doesn't seem to fly that different from one with good flying qualities.

The reason I said dihedral "is very important in full scale aircraft..." is because I was trying to say that having positive lateral stability in r/c aircraft isn't quite as important. With full scale aircraft being able to command sufficient roll control with the rudder is important. But in most r/c aircraft it just doesn't matter (Unless of course your trainer has no ailerons).

Just answer this: Have you ever flown an aircraft with the c.g. well behind the most aft c.g. specified (other than 3D flight)? If so, how did it fly?