Thank you for your kind words. The airfoil and lift distribution, along with the differential set-up of the elevons eliminate the need for drag rudders. Elevons are all that is required. You can see of a flight video of the 1/2 scale prototype of this wing at: http://www.bellimelgroup.com/videos/figure_8.wmv
You'll notice that it flies very smooth, even in 15 MPH winds and there is very little adverse yaw and dutch roll tendencies.
The two engines, turning in opposite directions help during the take-off roll. During the first portion of the roll when there is not enough air flowing over the wing to make the control surfaces effective, the engine torque is noticeable. The wing wants to turn to one side. In the air, engine torque is not noticeable. However, there are ways to counteract this torque on a single engine, pusher-prop wing. I learned through plenty of take-offs. So, two engines turning in opposite directions are not required. I've attached a picture of a single-engine pusher prop version.
Before building a big wing, I'd encourage any future wing driver to build a smaller version somewhere in the 60" to 80" range and get some stick time on it while they build the bigger one. Pure flying wings are unique and wing pilots need experience with orienting the wing profile in the air. I have over 200 flights on my electric Northrop N9M.
These wings attract ALOT of attention at the flying field. They are unique and no one else has one. When I fly one of my wings alone, someone will always show up because they have seen "something weird in the air" and then they want to talk to me about it. If I take it to the field and there are other pilots there, the wing becomes sort of a "noon-time show" because everyone wants to see the wing fly and then talk about it afterwards. Lots of questions. The wing is the center of attention at any field or fly in.
Thanks again for your questions.