This is a quick and dirty start to an X-plane simulation.
I took a O320 LongEZ, same engine, just added coaxial propellors driven
through a transmission by the single engine. Not optimized yet, props
still fixed pitch.
It's really stable in level flight, unlike the original which tends to
fall off left or right (just like my real Long-EZ).
When I pull the nose up to zero airspeed it gets into this inverted deep
stall that is (so far) not recoverable, and loses altitude at only 1000fpm!

It will be very interesting to play with this model.

Perry

I really think a canard would have adequate control authority with the
flight surfaces especially if it had a smaller rotor disk with more energy
in the airflow.

Steve

It might but I sort of like the gimbaled gear box idea and it is cheap
and easy to implement. That will work for sure.

BTW I just had a stunning idea for the counter rotating gear box that is
so good I can hardly believe it. 3D's shortly.