Brenner

Hey Steve,

This is an excellent question. In fact, a lot of pilots have been asking the same thing, and so far there are several ideas and concepts that are emerging:

1/.. Airframe Drag

Airframe drag is not needed as much to control the speed of the aircraft on downlines because the Contra Drive provides more than enough downline braking to do the job. This means that an airframe with less drag will have a wider speed range, and will take less mah out of the battery pack.

2/.. Yaw Stability

Zero degrees of right thrust, and no spiral airflow over the fuselage means that additional features are required to add dampimg in the yaw axis for Contra Driven planes. This can be in the form of larger rudder fin area, sfgs on the stab or wing, or perhaps a longer tail moment.

3/.. Fuselage Side Area

The absence of spiral airflow over the fuselage changes the aerodynamics of the fuselage. This means that the amount of fuselage side area, and the distribution of fuselage side area, may have to be different from current aircraft to optimize rolling performance, and minimize mixing between the rudder and other controls.

It's been interesting to see how different aircraft adapt to the Contra Drive. For instance, my Integral needs additional damping in the yaw axis, which I accomplished with the use of triangular strips on the trailing edge of my rudder, whereas Angus Balfor's Valiant didn't need any changes at all to fly well. Dave Snow's Spark also needed additional yaw damping, but not as much as my Integral, and the Wind S Pro needed just a slight increase in yaw damping.