In the midst of putting a Javelin together and looking at the push-rod for the elevator(s). It uses a split elevator with the standard wishbone push-rod system we've all seen many times. My question/problem: The whole wishbone (well, that's my term for it) push-rod system sucks, in my opinion. Most of the systems I've seen have the servo axis normal (perpendicular) to the elevator hinge line- as does the Javelin. Due to the angular displacement brought about by the rotation of the servo, the split elevators are- to some degree- not coincident in their travel throughout the full range of deflection.

If the servo were turned 90 degrees so its axis of rotation was parallel with the elevator, this problem would disappear. Granted, the elevator motion/rotation is not linear since the servo wheel/arm, etc, has differing amounts of angular displacement as it's rotated through the limits of its rotation but the push-rod would not be imparting differing amounts of input to each elevator half- thereby eliminating a built in roll component.

Now, all that being said, I'm well aware that plenty of very good planes exist with this system but I've got to wonder about it, all the same. Other than turning the servo on its side or installing one of those nifty bellcranks Central sells (http://www.centralhobbies.com/contro.../Bellcrnk.html), what are my choices? Connect the elevators and use a single push-rod? Two servos?

The question is basically an academic one; as I said, I know there are plenty planes with this set-up. It still gives me a big pain when I see it and wonder if anyone else has pondered this. Sorry for the long winded discussion.