ORIGINAL: invertmast
Oli,
what if the pivot was located at roughly 22.5% MAC? From my research it seems that this is still within the acceptable range of 17-25% MAC for the pivot location, so i'm assuming that the stab will be slightly more unstable at this position than if it was positioned at 17 or 20% Mac... is my understanding correct on this?
Thomas, in theory the CL does not move when changing the AOA. That is for NACA 00x series profiles. If you make a very accurate NACA 00x stabilator profile with a very good structural rigidity, you'll be fine.
If the CL of you surface stays at 25% MAC at all times, your stabilator will be stable at all times.
You can always "wind tunnel" a half stabilator from your car. But as a matter of precaution I would strongly recommend you to go with the 17% figure.