On the subject of CG and it's effects :


Most primary RC trainers are designed to self recover from pilot input, though today electronics can provide this function. This meant that when flying level, there is one throttle setting that will bring the aerodynamic forces into balance. It the model flies faster, then it climbs, and when going slower it loses altitude. Over a period of time the model when upset will eventually return to level flight, although it will still have both long and short periods of pitch oscillation. This is also similar to the force set-up of most general aviation aircraft.

Having the GC more forward amplifies this effect, making the model more sensitive to changes in speed. The most common method to compensate is to add down thrust, but not always the best method. As noted by several, decreasing the wing incidence can also reduce the ballooning effect. But moving the CG back and reducing the elevator travel is also effective when combined with other methods.

In this digital world, aerodynamics is one of the last true analog functions you may encounter.