Shubova, thanks for the information, yes the OS 120 flys very scale, my friend and I want to try to do some formation flying, and I need something with more power, I have the Saito 1.50 that I was going to use in a biplane I am building, but that one won't be ready for a while, that is why I was thinking of the 1.50, all I need to do is pick up a pitts muffler. Do you have any photos of your installation posted on the thread? Thanks again !