I am currently building a Do 28 D Skyservant with a stabilator. I have a question concerning the loads imposed on the controling servo. I've been told that I will need a servo with twice the normal torque due to the load imposed by the relative wind on the stabilator when actuated. In my opinion I do not see a need for a stronger servo. I'm guessing that the load imposed on the leading edge of a deflected stabilator will be offset by the load imposed on the trailing edge. Am I correct?
As a point of information, the pivot and horn are placed at the 50% chord position.

You've got the right idea but the wrong way to implement it. If you leave the hinge and pivot axis at the 50% point you're in for a world of hurt and likely a whole lot of flutter.

The center of aerodynamic torques on a symetrical airfoil or a flat plate actually occurs at around the 25% point when air is flowing over the leading edge up to some fairly high angles. This is why if you try to glide a sheet of balsa it'll immediately flip up or down (depending on the angle of attack you launch it with) and happily rotate itself all the way to the ground. Through a fancy set of sketches this can be shown to be because of the fact that the CG is at the 50% chord point but all the aerodynamic force is at the 25% point. So to truly reduce your servo load to the absolute minimum you need to put your hinge axis at the 25% point. If you find drawings of the Skyservant that are detailed enough you'll find that the full sized axis is at or just a % or two in front of the 25% point for just this reason.

Hopefully it's not too late to move it because if you leave it where it is you WILL need a huge servo to control it. Even then that won't cure the very likely flutter issue you'll have.

It's only too late for a change if the aircraft returns to kit form first.
I am in the process of building a new stabilator with the pivot at 25% chord and actuating it from the forward splicing tube, located at the leading edge.
Before I read your response, I hooked everything up and tried to move the leading edge up and down with my finger. It had some movement and my mind imagined it clattering up and down at flying speed. Not good!
The original plans and article (RCM 1977) did not state any problems with flutter, but I suspect it didn't attain much in flying speed since it was powered by two glow .15's. Mine will be powered by two 2915-5T-8Y Tower Pro brushless motors swinging 3 bladed 9-7 props.
A friend of mine pointed out the construction article of Keith Sparks MD-80 in Flying Models (Nov. 06) and he has the pivot point of the stabilator at about 5% with the swept wing design.
Thanks for your help.

Bob

I wish you a very successful first and many subsequent flights.