Cavalier? Nah. My understanding is that Carl Goldberg products are pretty well designed, and at a design weight of 7.5-8.5 lbs, the final thrust/weight ratio should end up being greater than 1, depending on prop selection. The engine recommendation from the CG website is a .60 two stroke or .90-1.20 four stroke. Admittedly the torque of the 4 strokes is better, but the final power rating of a .60 two stroke or the .90 four stroke are similar. The OS 60 fx is a ball bearing engine, and should have enough power to adequately fly the plane, although it might not be perfect for the extreme 3D maneuvers. The wing loading works out to about 20 oz/sq ft (assuming the 8.5 lbs final weight), which is not a floater, but pretty tame, so the OS 60 fx should be more than capable of generating enough ground speed for an easy takeoff. I've got a plane that weighs in at nearly 7 lbs, with wing loading at 22 oz/sq-ft, with a Thunder Tiger GP 61 (not nearly as much power as the OS 60 fx, and it flies quite nicely.

Consequenty, I don't consider my statement cavalier. Simply it means you don't need to second guess the designer. Would more power be good? Possibly, maybe even probably. But he has the designer recommended engine. Why not try it?

Brad