Hi Eric

I am pretty well convinced that the CG causes the majority of the
effect of keeping airplanes form stalling in a steep turn.

The CG will determine the AOA of the stabilizer at 1G and the
stabilizer size will determine the ratio of how the AOA varies with G
loading. A small stabilizer will reach the critical angle of attack
quickly and large one will not. For Example if the CG is at the
Center of lift on the wing then a symetrical stablizer would be flying
at an AOA of zero in level steady flight. Obviously in the AOA of the
Stablizer has to increase (in the down direction) to increase the AOA
of the wing. The size of the stabilzer will determine how much the AOA
increases.

On a side note this is actually one method that is used by test
pilots determine the aft CG limit for aircraft. They incremently move
the CG aft and put the aircraft into a steep turn at low airspeed. As
long as the aircraft exibits positive control pressure through out the
turn the CG limit is adequate. As the control pressures go neutral the
aircraft is at it's aft limit. If the CG goes any further back the
pilot would have to put forward stick into the turn to keep the the
airplane from increasing the AOA to the point that the airplane
stalled. I know this because it is how we determined the AFTCG limit
for the Thunder Mustang.

My HP16T had the opposite problem when I bought it, the CG was so far
forward that I could not fly at less than 60kts in a 60deg bank. The
stabilizer would stall and the nose would pitch down with the stick
all the way back. I would have to roll out of the bank to bring the
nose back up.
After a Weight and Balance and 4lbs in the tail and I can turn at
45kts an a steep bank and the nose has no tendance to drop.

Brian Case
CFIIG/ASEL