J Johnson, A center mounted tail on a canard has virtually no
lever arm
length and would be huge, if moved back wetted area and CG
problems are a
concern. The wing tip rudders deflect outward only on most designs and
affect drag far from the CG to yaw the aircraft, and a 2 degree
incidence is
believed to turn drag into a small thrust vector when not deflected.

george grimes

George, I think we're in agreement! Having the tail right near
the props is not going to have alot of effect [hence the thought
of extending the tail [empennage] . Control of asymmetric thrust using
drag /tip rudders seem's to be counter intuitive in that during single
engine operations one needs ever ounce of thrust they can get..

I think the better option here [my opinion only] would be to create
some form of a dual props in an axial config, best of both worlds
so to speak.

Fwiw

J. Johnson

You guys are missing a little something. The Rutan rudders move only
out. They do more with drag than they do with side force.
Since the lever arm is so great a little bit of drag goes a long way.
Pardon the pun :)

Sort of like th split ailerons on the Northrop flying wing.

Paul Lamar