Dino,


The 1.60 (26 cc) is very powerful, but even with the #3266 tuned pipe, its power will be border-line for a 12 lb. 3-D aircraft.

The 2.15 (35 cc) is powerful enough for this model, even with its own weight difference.

...But the 45 cc engine, with the magnesium crankcase, is significantly more powerful and it is lighter than the 35 cc engine. Low weight contributes to better flight performance, especially in a 3-D plane.

It costs a lot more, however.