I built the Brian Taylor Kingfisher. The Kingfisher was also a Chance-Vought built aircraft like the Corsair. In the Brian Taylor plans it showed the off set fin. I also questioned this during my build and I believe Chad Viech commented about the original being off set and that Brian Taylor drew his plans to scale. I built mine without the off set but did use some right thrust on the model. Some mention was made to the effect of the off set fin and engine speed. Rudder trim might have to change to correspond to the speed of the aircraft when using the off-set where the trim would basically stay the same when using the right thrust. Not sure if this is the case, just that the possibilities were discussed.