I'm running a OS .46FX with a Mac tuned pipe. I only have a few flights on it so I have not had a chance to really know the plane but I do like it. With full rudder it just holds on to knife edge. I have heard from several people it need's 1/2 to 1 inch surface added to the rudder to get a good knife edge out of it. But beside that I really like it so far.