Thanks John!

I don't know if there is interest by others, but if you are willing to work with me a little on this I will definitely give it a shot! (I am sure there are other Twin-Air builders watching this thread closely, right? ...right? Where are you guys?)

BTW I caught the Bill's incidence "error" but was afraid to mention it. I had my hands full with the ackerman and dihedral debates!

I was able to sort out your linkage setup from the photos and description and it looks quite simple. And I see you have the control hookup on the rudders in-line with the hinge lines to keep the control surfaces parallel as they are cycled. Some questions-

I assume that you have flown the plane in the pic. Does the control rod positioned just in front of the elevator hinge line disrupt airflow enough to make a noticable difference in the elevator response while in flight?

The plan pics for the 15 that Bill posted appear to put the back edges of the rudders in-line with the elevator hinge. Obviously, this is not the case for the 25 that was built since the rudder hinge line is even with the elevator hinge line (at the rear end of the fuse). Were the rudders simply pushed back?

The pics seem to show that the rudder surfaces extend below the elevator line, and the elevator ends are cut back to allow rudder travel. Is this correct? If so, then the rudders must be positioned at the very outer edge of the stab (not positioned at the line where the stab tips are glued to the forward part of the stab assembly as shown in the 15 plans)

And finally, what impact does the twin-tail have on flight characteristics on the 25 "prototype"?

Assuming that I decide to go for it- I can send you ACAD sketches before I start building anything if you are interested in taking a look...

Walt