Just an update to my last post about 10 weeks ago. The switch I made to the OS 70 Surpass II has worked well for me. I had to add a little tail weight since the Surpass II is heavier than the FL 70, but it was worth it. I have been having a ball with the Excelleron 50 and OS 70 Surpass II. The engine is purring now and has unlimited vertical as long as I keep her straight up with the rudder and elevator, as anticipated. She is just so stable, flies fast when needed, and slows down for perfect landings. Speed envelope is very wide. Been able to learn rolling circles (roll to the right for a left circle). I love this plane! The only fault has been the stars are peeling off after so many flights! Jon