I couldn't say for sure what would happen if the horizontal stab was removed from one of the PT family of gyros. I am fairly certain they can be quite a bit smaller on both the original 1/2a PT Gyro and the PT25 though. Those were both drawn up using the "that looks about right" method. The PT Profile stab was drawn up in a different manner. For those of you with sharp eyes will notice that each stab/elevator half is exactly the same as the fin/rudder shape but with a cutout for rudder travel. Still very unscientific but it is smaller percentage wise than the 1/2a and PT25 models. Goes back to my earlier statement about keeping it all simple. That's as simple as it gets with a CAD drawing to come up with a 'shape'! Would it fly with no stab? There's only one way to find out... Chop Chop
Mark
www.flyingbalsa.com