Chip and others,
This is my first own design aerobatic model. It fly's basic stuff well but has a violent pitch up when rudder is applied. After having noticed it and searching this forum I found that it is called rudder pitch coupling and it is caused by a uneven pressure distribution at the upper and lower side of the stab.
Looking at some proven designs (Synergy, and your designs etc.) I can see that the stab is not as low placed as mine but in your designs the stab is mostly placed in the lower half of the fuselage, contrary to some other designs where the stab is place more or less above the middle-line of the fuselage.

I would like to know from you in which way you determine the correct position of the stab. Is it calculated for each design or just by trial and error?
Is the optimal position for the stab in a given low-wing configuration the same as in a shoulder-wing configuration or is the position in a shoulder wing ideally higher to be more in line with the wing?
For this model where would be the optimal position?

Thanks for your input,
Hans


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