I also agree with all of you about the trainer (now after my wake-up call). I got ahead of myself with the Cub. I'm glad I got the Cub because I had a great time building it, but I'll just have to wait to fly it. I currently run an OS 40LA in my LT-40 and it seems to do well. How would this compare with the FS70 in the 60 4*? I'm not worried about unlimited vertical (yet). The instructor who flew the Cub said if anything it was a little overpowered with the .70 engine. The Cub is a .40, but I may put floats on it at a later date, so I wanted the bigger engine.

p.s. I looked on Tower Hobbies at the .60 4*, and they gave the engine range for a 4 stroke as .65 - .90.