Jim who? Thanks Squeakalong, I particularly like the Knockabout also. I fly all kinds of airplanes, but I always take the Knockabout along for a bit of pure, no-stress fun at the end of the day.

The changes to the 90/120 Super Sportster to make it a twin turned out to be a bit more complex than the original 40 size. (Or maybe I'm more detail oriented now, 25 years later.) And RCM is no longer around to publish it. Anyway, this one is just for me.

Ken: If both engines accelerated at exactly the same rate during take off, then a tail-dragger twin would react just like a tail-dragger single. In full scale, the pilot can coordinate the engine speeds but model engines almost never accelerate together. The asymmetrical thrust combined with the natural instability of a tail-dragger on the ground makes every model twin tail-dragger takeoff a gamble. Tricycle gear helps to dampen the asymmetrical thrust.

If you build your twin as a tail-dragger, a good gyro is highly recommended

Jim